2021 Atlantic Hurricane Season Early Forecast

12 04 2021

Dale C. S. Destin |

We could have a repeat of the record breaking 2020 Atlantic Hurricane Season this year. My early forecast for the 2021 Season is out, and it calls for above normal activity being likely. It predicts the most likely number of named storms (tropical storms and hurricanes) to be 21; however, there is a 70 percent or high confidence of the number ranging between 17 to 30. Recall that we had an unprecedented 30 named storms last year.

My forecast also calls for an accumulated cyclone energy (ACE) index of 184 with a high confidence of the range being 109 to 275. The ACE for the 2020 Season was 185; just one more than is forecast for this year. Also predicted are nine hurricanes with a 70 percent confidence of  the total being 6 to 14 and 5 major hurricanes with high likelihood of a range of 2 to 7.

If this forecast pans out, this season would be the third most active since 2005, in terms of ACE, and the 11th most active in the series dating back to 1851. It would also be ranked third for the highest number of named storms and tied for 11th and 17th for the most major hurricanes and hurricanes respectively.  

According to other forecasts surveyed, the average is for an ACE of 151, 18 named storms, 9 hurricanes and 4 major hurricanes, an above normal season. This is generally consistent with my forecast but with a notable 22 percent less activity (ACE). Notwithstanding, I am very confident in the forecast; last year, my forecast consistently called for more storms than virtually all else and was the only one that indicated that the 2005 record could be broken and that we could get 30 or more named storms. However, regardless of the forecast, you should always prepare the same each season, as it only takes one hurricane to ruin your year and or life.

Accumulated Cyclone Energy (ACE) based on 6 forecasting entities.

Recall that the ACE is the universally accepted metric used to classify the overall activity of a hurricane season. It takes not only the number of named storms into consideration but also their intensities and duration. For example, the 2020 season had a record 30 named storms, eclipsing the record of 28 set in 2005; despite this, the ACE of 185, ranked it as the 10th most active season, eight spots behind 2005, which had an ACE of 250 and nine spots behind 1933–the record most active season with an ACE of 259. With respect to some other notable records, 2005 still holds the record for the most hurricanes with 15, and remains tied with 1961 for the highest number of major hurricanes–7.

The main reasons for the above normal forecasts are the likely above normal sea surface temperatures across the tropical North Atlantic and a cold-neutral El Niño Southern Oscillation (ENSO) during August to October–the peak of the hurricane season.

A typical season, based on the standard climate period 1981-2010, has 12 named storms, 6 hurricanes and 3 major hurricanes. Major hurricanes have sustained wind speeds of at least 178 km/h or 111 miles per hour (e.g., Category 3 or higher), according to the Saffir Simpson Hurricane Wind Scale. The last Atlantic hurricane season–2020, will be most remembered for the record 30 named storms with Major Hurricanes Laura, Delta, Eta and Iota. Collectively, they accounted for over 300 of the over 400 deaths from tropical cyclones and caused over US$32 billion of the US$51 billion in damage. The season also produced 13 hurricanes and 6 became major hurricanes.

Satellite images for all 30 named storms from the 2020 Atlantic Hurricane Season. Credit WMO

This forecast will be updated monthly around the 10th of each month until August. The first update will be issued around May 10.

The Atlantic hurricane season officially begins on June 1 and concludes on November 30; nevertheless, in the last five years, there have been preseason tropical cyclones–be prepared!

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Drought is Back

14 03 2021

Dale C. S. Destin |

Drought is back for Antigua. A slight meteorological drought is present as of the end of February. It is most likely to get worse over the next three months, as below normal rainfall is forecast by most models.

The rainfall for winter – December to February (DJF) 2020-2021, was 149.1 mm (5.87 in). This total is deemed below normal and beneath the drought threshold. Usually, DJF yields 225.8 mm (8.89 in) of rainfall, on average; hence, there is over a 75 mm (over 3 in) deficit or a 34 percent shortfall.

Rainfall for Antigua for the period December 2020 to February 2021. Picture in the background is Potworks Dam as of March 3, 2021 courtesy Karen Corbin of the Humane Society.
Rainfall for DJF is well below the slight or worse drought threshold, nearly at moderate drought. Rainfall for this period for Antigua shows no significant trend (black dashed line). Excess rainfall tends to be more extreme than drought rainfall.

The month that is mainly responsible for the scarcity in precipitation is January, which got only 41 percent of the normal amount of 67.3 mm (2.65 in). The rainfall for February was also lower than usual, accounting for 73 percent of the normal amount of 50.0 mm (1.97 in). The rainfall for December was near normal.

The two-month rainfall for January-February (JF) of 63.8 mm (2.51 in) is the lowest since 2001. Thus, the very dry start to the year continues. With this JF ranking the eighth driest on record, only seven other years have had a drier start on record dating back to 1928.

It normally takes a few months for the effects of a meteorological drought to descend to a hydrological drought and cause potable water issues. However, the effects are already manifesting themselves in the lowering of water in catchments. Yesterday, the APUA Business Unit Water Manager – Ian Lewis, said on Observer Radio News that the country has about three to four months of surface water remaining, at current extraction rate.  

We were last in a drought April to October last year. This was a severe drought that was more than meteorological; it resulted in surface catchments transforming into mud patches and then to grass lands. It is unclear, at this stage, whether there will be a repeat of similar rainfall absence this year.

The dry conditions last year, resulted in water rationing and almost a 100 percent reliance on desalinated water. Ian Lewis has already indicated that the absence of notable rainfall over the coming months would usher in return of the water conservation schedule better known as water rationing.

Antigua is not alone in experiencing notable rainfall deficits in the wake of winter. Much of the Caribbean is suffering a similar fate, from a drier than usual dry season, thus far. Short and long-term droughts are evolving across a number of islands and there is the potential of several others joining this drought-list.

Rainfall anomaly (departure form average) in mm for the Caribbean, based on CMORPH data

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Very Dry Start to 2021

16 02 2021

Dale C. S. Destin |

Antiguans have just witnessed the driest start to the year in over a generation. January 2021 was the driest January since 1977 for Antigua, with an island average of 27.4 mm (1.08 in).

Usually January yields 67.3 mm (2.65 in) of rain; however, this time, the total was down by 59%. This puts the rainfall for the month in the well below normal category – the bottom 10 percentile of the most recent climate period – 1991 to 2020.

Such low rainfall is rare for January. How rare? Once in every 27 years, on average, which translates to a 3.7 percent chance of such a low total annually. Usually, there is over a 96 percent chance of the month producing more rainfall.

From a historical standpoint, this is the third driest January on record dating back to 1928. Only January 1977 and 1931 have been drier. January 1931 is the driest on record with 16.3 mm (0.64 in) and January 2006 is the wettest with 2017.7 mm (8.57 in).

Despite the trickle of rainfall for January 2021, the rainfall for the month is usually the most reliable of all months with the lowest variability index of 0.83 or moderate, for the climate period 1991-2020. All other months have a variability index of 1 to 2.37 or moderate to extreme. The variability is obtained by dividing the difference in rainfall of the 90th percentile and the 10th percentile by the median.

Notwithstanding the drier than normal January 2021, the rainfall for January remains without any significant (statistical) trend. The mean rainfall over the past seven climates has not changed significantly, ranging between 65.8 to 79.5 mm (2.59 to 3.13 in), over the period 1928 to 2020.

As we look forward, the rainfall for February is lagging average by about 38 percent, and even if the averaged is reached, there is the high likelihood for rainfall to drop to drought levels by the end of February. About another 35 mm (1.38 in) of rain is needed to stave off drought. This or more rainfall for February 17-28 has only occurred 10 times in the last 55 years – 18 percent of the time.

January is unlikely to be this dry again under the next 27 years. By then, we will be at the middle of the 21st Century – millennials would have reach senior citizen age.

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The Great 1843 Mother of All Caribbean Earthquakes

8 02 2021

Dale C. S. Destin |

At 10:37 am, February 8, 1843 – 178 years ago today, the mother of all Caribbean earthquakes struck the region. This is believed to be strongest of all Caribbean earthquakes, ever reported. Dubbed the “The great 1843 earthquake” by Beauducel and Feuillet of the Institut de Physique du Globe de Paris, it killed more than 1500 people and perhaps up to 6000, most in Guadeloupe, and caused catastrophic damage.  

Earthquake event of 8 February 1843, where black star, southeast of Antigua, indicates epicenter from Feuillard [1985]. Thick dashed lines, with roman numerals between, indicate approximate isoseists – equal earthquake intensity. Dashed areas show the approximate size of the ruptured zones estimated by using the Wells and Coppersmith [1994] relation between rupture length and magnitude. See Natalie Feuillet et al

The powerful earthquake, with an estimated magnitude of 8.5, struck the Caribbean, with epicentre between Antigua and Guadeloupe. Different sources have it centre in slightly different places, which is not unusual; however, all have it within 50 miles of the above-mentioned islands.

The monster quake is credited with the total destruction of the Guadeloupe city of  Pointe-à-Pitre. What the shaking did not demolish directly, fire sparked by it consumed the rest. Eyewitness accounts and newspaper reports painted a very dismal picture of the aftermath of this earth-shattering quake, which caused damage throughout most of the Eastern Caribbean. Here is an account of damage to Antigua, according to an 1843 report by Captain of the ship – Royal Mail Steam Packet Dee, as cited by José Grases G. 1990 and obtained from the The University of the West Indies Seismic Research Centre (UWI-SRC) website:

This island has suffered most severely, the whole of the churches and mills throughout the island being a heap of ruins. The organ in the Church of St. John’s totally destroyed; the Dockyard at  English Harbour is sunk considerably, many parts being under water, the whole of the  stone houses in a complete ruinous state, the walls partly or wholly down; the water tanks containing nearly 11,000 tons of water burst with an  awful crash; the earthquake lasted about 4 minutes. Mr. Hart, Clerk in charge of the Dockyard, English Harbour, states that 3 clocks in the  neighbourhood  stopped  at  10h:  40M:  a.m. Precise accounts had not  been received from the  interior. It is ascertained 40 lives had been lost – fears were entertained it was short of the actual loss. The Governor’s House (Dow’s  Hill) is partially destroyed with nearly all its furniture; the  Ridge Barracks much damaged; the Custom House, Court House, and Wesleyan Meeting House destroyed.”

No photo description available.
Damage from the 1974 Antigua earthquake. The 1843 earthquake was 10 times stronger. Photos by UWI-SRC

This earthquake, which ranks among the top 20 strongest ever in the world, was said to have been felt as far away as New York, USA. It was probably a megathrust earthquake – the most powerful kinds. It was up to 10 times stronger than the infamous 1974 Antigua earthquake and up to 32 times stronger than the 2010 Haiti earthquake.

It must be noted that there are conflicting estimates of the magnitude of this catastrophic event with, at least, one expert indicating that the magnitude was as low as 7.5 to 8. I am more persuaded  by the 8.5 magnitude estimate, since this appears to be the most recent finding – Natalie Feuillet et al., and also supported by, at least, two other experts. In some literature it is listed at magnitude 8.3. At any rate, it was not your garden variety earthquake by any stretch of the imagination.

According to the UWI-SRC, earthquakes are a daily reality across the Caribbean, especially the northeast Caribbean where hundreds occur annually, although most are not felt.

Over the years, the UWI-SRC has expressed concerned over the potential for an 1843 or 1974 caliber earthquake impacting the northeast Caribbean. Although earthquakes, especially large ones, are virtually unpredictable, the public should be prepared, as moderate to significant sized earthquakes may impact the region at any time. Individual, community and national measures should always be in place to mitigate the impacts of earthquakes.

For more on seismic activity in the Eastern Caribbean visit: UWI-SRC. Also please continue to follow me for all things weather and climate via TwitterFacebook and Instagram. Share this blog, if you found it useful.





High Surf Events This Week

27 01 2021

Dale C. S. Destin|

Much higher than usual surfs are expected to pound the shorelines of much of the Eastern Caribbean. One episode is getting underway and will last for 24 to 36 hours. A second episode will occur over the weekend. These surfs are expected to cause the threat level to rise to high for life, livelihood, property and infrastructure of those using or living on the affected coastlines and there is the potential for extensive impacts.

Past Surf Event - James Beach
Fort James Beach, Antigua, During a Past High Surf Event

Based on the expected swells, which will transition to surfs when they reach near shore, surfs over 3 metres (10 feet) are projected to take place at times. Advisories and warnings are expected for a number of islands.

The first hazardous surf event is likely to subside by Friday for most areas but rise again over the weekend. The second episode of dangerous surfs will start across the Bahamas on Friday and reach the Eastern Caribbean by Saturday.

It is the surf season, when powerful winter storms come off North America, often packing the equivalent of tropical cyclone winds, sometimes reaching winds equal to hurricane strength. These systems frequently track across the “pond” from the United states to Europe, all the while pushing large swells toward the Caribbean and elsewhere, resulting in hazardous conditions along mainly north and east-facing coastlines of the islands.

5-day plot - Swell Height at 41044
High Swells Heading for the Eastern Caribbean to Become High Surfs or Breaking Waves Near Shorelines

The coming high surf events will be due to a series of winter storms. The one that will cause the surf episode over the weekend will be a storm, whose pressure drop by 24 millibar or more in 24-hours. Such winter storm systems are called bomb-cyclones.

There is no strong wind concern for any of the islands. The concern is for mainly Atlantic coastlines for especially the Northeast Caribbean – from Puerto Rico to the northern Windward Islands.

Potential impacts include but not limited to:

  • loss of life;
  • injuries to beachgoers;
  • salt-water intrusion and disruptions to potable water from desalination
  • disruptions to marine recreation and businesses;
  • beach erosion and
  • sea water splashing onto low lying coastal roads.

All should be very wary about bathing in the impacted areas. Personally, although I can swim, I do not plan to go to the beach during the times the surfs are expected to be higher than usual. Going rock fishing is not advisable.

The concern is not only for high surfs, but also rip currents. Rip currents are powerful channels of water flowing quickly away from shore, which occur most often at low spots or breaks in the sandbar and near structures such as groins, jetties and piers. High surf events make for very conducive conditions for rip currents.

If caught in a rip current, relax and float. Don’t swim against the current. If able, swim in a direction following the shoreline. If unable to escape, face the shore and call or wave for help.

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Extreme Winds and Seas to Usher in the New Year

28 12 2020

Dale C. S. Destin |

Extreme wind and marine events are forecast for this week across the northeast Caribbean, including Antigua and Barbuda. The howling wind event will take place Thursday – NEW YEAR’S EVE, through Saturday – January 2, whereas the life-threatening marine event will take place New Year’s Eve night through Sunday – January 3. Warnings and advisories for strong winds, rough seas and high surfs will be required for most islands.

Northeast Caribbean: Estimated max 3-second gusts; max sustained 10-minute winds; average of the top 10% of significant wave heights and average of top 10% of swells

The angry winds and seas could cause notable socio-economic impacts to the islands. Similar actions by nature, earlier this year, caused ships to turn away from Antigua and Barbuda and cancelled ferry services. There were also reports of LIAT aborting landings in some islands; banana trees being downed in some countries and power outage in some areas.

The kick-off of these unwelcome but not unusual events is expected on Thursday. The pressure gradient will rapidly and significantly steepen, which will become evident by the closeness of the isobars – lines of equal pressure, on our weather maps. The closer the isobars, the steeper the pressure gradient, the stronger the winds and vice versa.

Gale-force gusts, the equivalent to tropical storm-force gusts, are likely – gusts exceeding 78 km/h (over 48 mph). Otherwise, the winds will frequently be above 40 km/h (over 25 mph). The maximum sustained 10-minute wind speeds will likely reach around 50 km/h (31 mph), whereas the maximum sustained 1-minute winds will reach around 56 km/h (35 mph). The strongest winds are forecast for New Year’s Day, especially across open waters, windward coastal areas and elevated places. The prevailing wind direction will be northeast.

Visualization of wind gusts (shaded) wind direction (short solid lines) and isobars (long solid lines with numbers – pressure in millibars) – December 31 2020 to January 4 2021

As the winds go, so go the seas. The tumultuous winds will cause the seas to rise and become extremely threatening – very rough in open waters on Thursday through Sunday. Significant wave heights could peak at or above 4 metres (over 13 feet), locally exceeding 5 metres (near 17 feet). The highest seas are also expected on New Year’s Day. These seas will be non-navigational for small craft and even some non-small-craft operators.

Significant wave heights according to the ECMWF WAM Model – December 31 2020 to January 5 2021

High swells and surfs (breaking waves) are also forecast for Sunday. Swells in excess of 2.5 metres (over 8 feet) and surfs in excess of 3 metres (over 10 feet) are likely. These breaking waves will make for very dangerous conditions for beachgoers and others using the coastlines.

The events will make for a high threat to the life and livelihood and property and infrastructure of mariners and users of the nearshore areas. There is also the potential for extensive impacts including the following:

  • Loss of life
  • Injuries
  • Damage or loss of boats and fishing equipment
  • Saltwater intrusion and disruptions to potable water from desalination
  • Coastal flooding from sea water splashing onto low lying coastal roads
  • Sea search and rescue disruptions
  • Cancellations to transportation (especially by sea)
  • Scarcity of sea food
  • Disruption or cancellation to sporting and recreation events (especially marine activities)
  • Businesses and economic losses

To be safe, mariners should stay in or near port and beachgoers should stay out of the waters for affected coastlines. Also, residents should secure light and loose objects, which can be blown away, and caution should be taken when driving. The anticipated blustery winds could make some outdoor activities uncomfortable, if not outright dangerous. These winds can also create dangerous fallen or blowing objects.

The turbulent winds will unsettle the atmosphere, resulting in brief heavy showers. However, rainfall accumulations will only be of minimal concern, at most.

These events will affect virtually the entire Caribbean Basin, at different times. They will start across the Bahamas and the Western Caribbean on Tuesday and reach the northeast Caribbean on Thursday. Then, they will spread across the southern Caribbean by Friday – New Year’s Day. The extreme events will come to an end by Sunday, January 3, 2021, although seas will likely still be hazardous for some areas, beyond Sunday.

At times, it may feel like there is a tropical storm in the area, but I can ashore you that there is none. The hurricane season remains over.

Check and monitor your local forecasts, from your national weather service, for details specific to your location. This is a relatively broad scale view; hence, the numbers WILL change either way.

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Post-Hurricane Season – December

19 12 2020

Dale C. S. Destin|

Named tropical cyclones (tropical storms or hurricanes) during December are virtually unheard of for Antigua and Barbuda. However, in 2007, Tropical Storm Olga came close and affected us. Its centre passed around 39 and 78 miles north of Barbuda and Antigua respectively – at least brushing our islands. Its impact was minimal.

Tropical Storm Olga – December 11, 2007. Credit Wikipedia.

Olga went on to become the most destructive and deadly tropical cyclone originating in December. The storm went on to made landfall on Puerto Rico and Hispaniola with peak sustained winds of 95 km/h (60 mph). It killed at least 40 people and caused US$45 million in damage across the Greater Antilles.

In the history of Atlantic named tropical cyclones, which dates back to 1851, only 16 have had their origin in December, according to NOAA. Of the 16, 5 (31 percent) were hurricanes.

All 16 tropical storms and hurricanes originating in December – 1851 to 2019

Of the 16 total December tropical storms and hurricanes, four impacted the Caribbean i.e. passing within 120 miles of the region. The last to do so was Olga. Based on the climate period 1981-2010, the chance of a storm impacting Antigua is about 3 percent, while the chance of the Caribbean being impacted is about 9.5 percent.

The strongest tropical cyclone owing its origin to December is Alice of 1954 – a Category 1 hurricane. Alice formed in late December and crossed over to January 1955 and impacted Antigua and the rest of the Leeward Islands with Category 1 winds. It eventually reached peak sustained winds of 150 km/h (90 mph) about 100-130 miles northeast of Barbuda. Alice is known to be the only post-season hurricane (forming in December, January or February) to impact the Caribbean.

The last Atlantic storm to have its origin in December is an unnamed subtropical storm of 2013. It formed over the northern eastern Atlantic, near the Azores. It had peak sustained winds of 85 km/h (50 mph). Lost of life and damage caused by it were nil.

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November 2020 Hurricane Summary

9 12 2020

Dale C. S. Destin|

The hurricane season saved the worst for last. November, the last month of the official season, produced the strongest Atlantic hurricane for the year – Category 5 Hurricane Iota, with peak winds of 260 km/h (160 mph).

Category 5 Hurricane Iota making landfall on Nicaragua – 17 Nov 2020

Iota devastated Central America, particularly Honduras and Nicaragua, killing 61 and causing at least US$564 million in damage. However, long before Iota was Iota, her precursor – Tropical Disturbance AL98, was quite destructive to Antigua. It dumped over 373 mm (over 14 in) of rain in 24-hours across parts of mainly western Antigua. This Lenny-type-rainfall caused massive flooding, resulting in inevitable damage in the hundreds of millions of dollars.

Iota not only became the only Category 5 hurricane for the season, but also the first Category 5 hurricane to have its origin in November. The 1932 Cuba hurricane, also known as the Hurricane of Santa Cruz del Sur or the 1932 Camagüey hurricane, became a Category 5 hurricane in November but has its origin in October, unlike Iota.

Iota’s late rise to Category 5 status also keeps the undesirable record streak of seasons going, with at least one such maximum category hurricane. The streak is at five seasons, dating back to 2016.

Tropical Storm Theta was the other named tropical cyclone to have its origin in November. It had peak winds of 110 km/h (70 mph) and minimal impact to the Canary Islands and Madeira.

Eta had its origin in October but developed into a Category 4 hurricane in November and impacted Nicaragua, less than two weeks ahead of Iota. This November tied with November 2005, 2001, 1961 and 1931 for the most storms named in the month.

With the formation of Iota, we were nine deep into the Greek Alphabet – the back up list for naming storms. Notwithstanding, Antigua and Barbuda and the rest of the Eastern Caribbean remained hurricane-free right through the season and was happy to see the back of November.

The hurricane season officially ended November 30, with a record 30 named storms, 13 hurricanes and 6 major hurricanes. Only 2005 is close with 28 named storms, a record that most never thought would ever be broken.  

Recall that an average season produces 12 named storms, 6 hurricanes and 3 major hurricanes, Thus, this season produced 250 percent of the average number of named storms, 217 percent of the average number of hurricane and 200 percent of the average number of major hurricanes.

Please continue to follow me for more on the hurricane season and all things weather and climate via TwitterFacebook and Instagram. Also, share this blog, if you found it useful.





Record-breaking 2020 Atlantic Hurricane Season Ends

1 12 2020

Dale C. S. Destin|

Five tropical cyclones present in the Atlantic – September 14, 2020

The busiest Atlantic hurricane season ever ended last night. The season produced a record-breaking 30 named storms. It also produced 13 hurricanes, the second highest on record dating back to 1851. Further, there were six major hurricanes, Category 3 and over, which tied for the second highest on record. The record season took over 400 lives and caused over US$41 billion in damage.

Only once before a season exceeded 20 named storms – 2005 with 28 named storms, which is the record eclipsed by 2020. However, 2020 remains second to 2005 with respect to the number of hurricanes – 15, and the number of major hurricanes – 7. Six other seasons have a similar total of major hurricanes as 2020 – 2017, 2004, 1950 1996, 1933 and 1926. An average hurricane season has 12 named storms, 6 hurricanes and 3 major hurricanes.

Ranking of the 2020 hurricane season based on number of named storms, hurricanes, major hurricanes and ACE, compared to the records

Although the most eye-catching statistic for a given season is the number of storms, this is not the metric used to determine its overall activity. The Accumulated Cyclone Energy (ACE) index is the internationally accepted metric used to categorise the activity of a season. The ACE takes into consideration not only the number of named cyclones but also their strength and duration. Hence, based on the ACE, 2020 is the 13th most active hurricane season on record, with an ACE index of 180. The most active hurricane season on record remains 1933, with an ACE of 259, 44% more than 2020.

Based on NOAA’s classification, the 2020 season was extremely active or hyperactive. However, NOAA’s classification of season has its challenges, allowing for one season to simultaneously have two classifications. A better approach is to classify seasons strictly by the ACE index. This approach would make the 2020 season and above normal season but NOT well above normal or hyperactive, according to 268Weather’s classification. It fell short by seven ACE needed to take it to 187 – 268Weather’s current threshold for a hyperactive season.

268Weather’s seasonal hurricane forecasts accurately predicted a very high likelihood of an above-normal or active season. 268Weather is proud to be among the few to have gotten the forecast right from very early – April. 268Weather was the only entity to forecast over 28 names storms, up to 32 were predicted and 30 formed.

Animated satellite imagery of the named storms that occurred during the 2020 Atlantic Hurricane Season – May 13 through November 18. Credit: NOAA Satellites

It was a relentless hurricane season. It kept forecasters on their toes continuously. There was an average of 4-5 tropical storms per month since June with one forming about every week. Thankfully, we were not significantly impacted by any of the season’s two-and-half dozen named storms, over a dozen hurricanes and half dozen major hurricanes. Also, the Eastern Caribbean virtually got away “scot free” from significant impacts.

The 2020 season got off to an early start with Arthur on 16 May and Bertha 27 May. From May to July, there was a record nine storms. This is more storms than 80 of the previous 169 seasons, including 2014, 1997 and every season from 1991 to 1994. By September 18, the 21-name Atlantic list was exhausted when Tropical Storm Wilfred formed. Thus, the season “went Greek” i.e. the backup Greek List was turned to for names for the remainder of the season. To date, we are 9 names deep into the list with Iota being the last and the most powerful Atlantic hurricane for the year.

The Atlantic has done a 5-peat – produced five active/above normal seasons in a row. This is the longest such streak, on record. Further, it’s the most active hurricane season since 2017 and the second most active since 2005. Eighteen of the last 26 hurricane seasons, dating back to 1995, were above normal.

The reason for the large percentage of active hurricane seasons since 1995 is due to the positive or warm phase of the Atlantic Multidecadal Oscillation (AMO). Positive phases of the AMO are strongly linked to active eras of Atlantic hurricane seasons, which historically last for about 20 to 40 years.

Like other active years, this year’s activity is owed to an interrelated set of oceanic and atmospheric conditions linked to the warm AMO, such as warmer-than-usual North Atlantic sea surface temperatures (SSTs) and cooler-than-normal middle to eastern equatorial Pacific SSTs i.e. La Nina. These conditions which are also associated with weak wind shear caused the record-breaking, extremely active hurricane season.

Other notable records set by the 2020 season include the following:

  • Twenty-seven tropical storms broke the record for the earliest formation by number
  • A record 10 tropical cyclones rapidly intensified, tying 1995
  • This season is the record sixth consecutive year with pre-season named tropical cyclones
  • A record 10 tropical cyclones were named in September with 9 having their origin in the month, the most for any month
  • Iota became the only Category 5 hurricane to have its origin in November and the latest on record

For more details on the 2020 Atlantic hurricane season, our monthly summaries: May, June, July, August, September, October and November (coming soon).

This season has officially ended, but it is possible, although not probable, for additional storms to develop. Stay vigilant and make sure your family is prepared for all hazards, especially those related to weather and climate. The 2021 hurricane season will officially begin June 1 and 268Weather will issue monthly forecasts starting early April.





Drought-Busting, Lenny-Type Rainfall Impacted Antigua

10 11 2020

Dale C. S. Destin|

A newly formed tropical disturbance caused drought-busting, Lenny-type rainfall across parts of Antigua. The system dumped over 373 mm (over 14 inches) across parts of the country, over the last 24 hours.

Of course, with this extreme rainfall, there was massive flooding in some areas. The impact is unfolding with images of almost submerged and abandoned vehicles, flooded businesses and homes and damaged roads.

This image has an empty alt attribute; its file name is image-10.png
Last Night: Flooding at Woods, St. John’s, Antigua
Today: Same area as above (Woods, St. John’s, Antigua) but after the runoff.

This rainfall event was quite extreme, if not in amount, certainly with respect to intensity. In 24 hours, two-and-a-half times the month’s total rainfall fell, yes 250% November’s average in less than 24 hours, in some places. The islands average rainfall for November is 149.4 mm (5.88 inches).

The maximum 6-hour rainfall was higher than the average for most months. We measured up to 156 mm (6.14 inches) in six-hours. This is more rainfall than we would have had from most tropical cyclones that have impacted the island. The max six-hour rainfall on record at the Airport is 175.2 mm (6.90 inches); the max for November for the same location is 158.7 mm (6.25 inches).

In an hour yesterday, we measured peak rainfall total of 97 mm (3.82 inches), at the University of the West Indies – Five Islands Campus. At the Airport, the record of 56.4 mm (2.22 inches) was broken by the 77.9 mm (3.07 inches) measured between 4 and 5 pm, yesterday.

Drilling down even deeper, there were occasions when the ten-minute rainfall total reached close to 25 mm (1 inch). This is almost unimaginable to think that in a space of 10 minutes, some areas would have had nearly an inch of rainfall.

Putting the rainfall total into further perspective, the one-day-total, for some areas, for this event is higher than the one-day-total from Lenny recorded at the Airport. Lenny’s maximum one-day total was 241 mm (9.49 inches), at the Airport, as compared to over 320 mm (over 12.6 inches) from this event, at Five islands.

More rain is in the forecast with another 100 to 200 mm (4 to 8 inches) possible in the next 72 hours. This means more moderate to major flooding is likely.

Potential impacts include:

  • loss of life and injuries;
  • widespread financial losses;
  • disruption to transportation;
  • soil erosion;
  • disruption of schools;
  • damage to dams, embankment, irrigation and drainage facilities;
  • decrease in storage capacity of reservoir due to high sediment rate;
  • contamination of potable water;
  • crop and animal losses;
  • environmental degradation;
  • disruption to communication and
  • damage to infrastructure. 

Stay alert and prepared. If or when a flash flood warning is issued, it means that, at least, moderate or worse flooding is imminent or occurring in the warned area. Thus, residents in these areas should move to higher ground immediately.

Do not drive your vehicle into areas where the water covers the roadway, as the underlying road may have washed away, magnifying the potential for harm. A flash flood watch means to prepare for the possibility of warning conditions.

Flooding across portions of Bolans, Antigua

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The Hurricane Season in November

9 11 2020

Dale C. S. Destin|

November hurricanes are almost unheard of for Antigua and Barbuda. I say almost because we have an exception – Hurricane Lenny of 1999. In 169 years of record dating back to 1851, Lenny is our (Antigua and Barbuda and the rest of the Eastern Caribbean) only November hurricane.

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Lenny south of the US Virgin Islands. Credit Wikipedia
The Track of Hurricane Lenny – November 13-23, 1999

Prior to Lenny, we in the Eastern Caribbean, have not had a November named storm (tropical storm or hurricane) since 1896 – over 100 years before Lenny. November named storms amount to eight for the Eastern Caribbean, four of which affect Antigua, with Lenny being the only hurricane on record.

Lenny impacted Puerto Rico, the Virgin Islands, the Leeward Islands, the Windward Islands and even as far away as Colombia. It killed at least 17 people and caused over US$785 million in damage, a lot due to flooding.

The Atlantic Basin, including the Caribbean, averages one November named storm per year, one hurricane every other year and a major hurricane – Category 3 or higher intensity, every 10 years; this is based on the current climatological period of 1981-2010.

To date, no Category 5 hurricane has had its origin in November, based on the record. There was an unnamed Category 5 hurricane in 1932 that formed in October but reach Category 5 status in November; however, storms are credited to the month in which they were formed or originate in.

The probability of Antigua and Barbuda being impacted by a storm or hurricane, in November, is around 3 percent, based on the 1981-2010 base period. This translates to, at least, a storm or hurricane every 33 years, on average. With Lenny being our last hurricane, we are not due another hurricane in November until around the year 2032. The same is true for a major hurricane, in November.

The probability of a storm or hurricane impacting the Eastern Caribbean, in November, is around 6 percent or one every 16-17 years. This increases to around 12 percent or one every 8-9 years for the Central Caribbean and 28 percent or every 3-4 years for the Western Caribbean.

November Hurricane Climatology
The zones of origin and tracks of named tropical cyclones (tropical storms and hurricanes) in November.

The last November hurricane for the Caribbean was Otto of 2016. It formed across the southwest Caribbean Sea and impacted Nicaragua and Costa Rica, then crossed over into the Pacific Ocean. It killed 23 people and caused damage amounting to over US$192 million. It is the last Atlantic tropical cyclone to crossover to the Pacific and only the 14th to have done so.

Infrared satellite loop of Hurricane Otto making landfall as a Category 3 hurricane in Nicaragua on November 24. Credit Wikipedia.

From 1851 to 2019, November has produced a total of 92 named storms of which 56 were hurricanes and 6 were major hurricanes. For the climate period 1981-2010, there have been 20 named storms, 14 hurricane and 3 major hurricanes.

 November 1-10 Tropical Cyclone Genesis Climatology
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 November 11-20 Tropical Cyclone Genesis Climatology
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 November 21-30 Tropical Cyclone Genesis Climatology
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It must always be noted that there are likely named tropical cyclones (tropical storms and hurricanes) that were missed prior to the satellite era – before the mid-1960s.

November 2005, 1961 and 1931 holds the record for the most named storms for the month – three. Further, 2001, 1994 and 1980 holds the record for the month for hurricanes – two. Meanwhile, no November on record has had more than one major hurricane in a year and only six have had a major hurricane – 2016, 2008, 1999, 1985, 1934 and 1912.

What will this November bring? Given that each month of this hurricane season has produced, 1.5 to 2.5 times its average number of named storms and that up to 32 named storms are forecast to the year, with 28 gone, this November could end up producing up to two storms, with one becoming a hurricane.

It is not over yet, but the end is nigh – November 30. Usually, November is a low stress month for hurricanes; however, this is 2020 – stay prepared!

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October Not Over 2020 Hurricane Summary

2 11 2020

Dale C. S. Destin|

The hurricane season was certainly not over in October. There was a record-tying number of major hurricanes – two, Delta and Epsilon; this represents over 665 percent of average (normal). The number of named storms – five, was 250 percent of average. Further, the number of hurricanes – four, was over 360 percent of average.

October Not Over 2020 Summary. Note, although Eta became a storm in November it is credited to October to which it owes its origin, according to the international standard

October 2020 is only the fifth October on record with two major hurricanes. The last time there were two major hurricanes in October was 2005. The month averages a major hurricane once every three to four years. Previous years with two major hurricanes are 2005, 2001, 1950 and 1894.

It was a very active October. The metric that speaks more completely to the activity of a month or a hurricane season is called the accumulated cyclone energy (ACE) index. Normally, the month produces an ACE index of 14.5 – that was more than doubled for this October – 39.2. Compared with the activity for September, although it was a record-setting month regarding named storms, the ACE index of 63 was only 1.23 the average – 51.4. Hence, October was more active relative to itself than September was.

Using the ACE index metric, this October was more active that 28 previous full hurricane seasons of 169, including the 2013 season, which had 14 named storms but an ACE of 36. Also, the two major hurricanes during the month were more than or equal to 125 full seasons. We would have also seen more or the same number of hurricanes than 71 full seasons, including 2015.

Every named storm in October was earlier than those with the same names that formed during October of the 2005 hurricane season, which is the only other season with more than 20 named storms, on record. The records were broken by as many as 41 days. This may be an omen for this season setting a record for the highest number of named storms.

Thankfully, none of these storms threatened Antigua and Barbuda and the rest of the Eastern Caribbean. The most we got were moderate to large swells from Epsilon along with minimal showers from a few very weak feeder bands. The rest of the Caribbean Islands fared well also with none experiencing storm or hurricane conditions. Delta was a relatively close call for Jamaica, the Cayman Islands and Cuba.

We are through the season, except for one more month, officially – November. Thus far, there have been 28 named storms – the most through October and tied with 2005 for the most on record, for a season. The 2005 record is now expected to be broken. There have also been 11 hurricanes of which 4 were major hurricanes – Category 3 or over.

2020 Atlantic hurricane season summary map.png

Recall that an average season produces 12 named storms, 6 hurricanes and 3 major hurricanes. Thus, this season has produced, thus far, 233 percent of average number of named storms, 183 percent of average number of hurricanes and 133 percent average number of major hurricanes.

Notwithstanding the record number of named storms, the season is very far from being a record active one. Recall that the activity of a season is based on the ACE index. The ACE index, thus far for 2020, is 143.9; this is only 136 percent of the average – 105.5.

This season is not even ranked in the top 20 with respect to ACE. It is currently at 27th and is unlikely to reach the top 10. The ACE index for a season is also a measure of the potential destructiveness of the collective named storms. This means that although 2020 has produced a record number of storms, there are several seasons that were potentially more destructive, including the 2017 season with and ACE index of 223.

Top 20 Most Active Atlantic Hurricane Season. TS – Tropical Storms; HU – Hurricanes; MH – Major Hurricanes. Credit Wikipedia.

The most active season on record, using the ACE index metric, remains 1933, with an index of 259, produced by “just” 20 named storms. This is nine more ACE than the 2005 season, which had eight (40 percent) more named storms.  

Delta – 5 to 11 October, became the record-tying fourth named storm of 2020 to strike Louisiana, as well as the record-breaking 10th named storm to strike the United States. It was a very destructive Category 4 hurricane with 1-minute peak sustained winds of 230 km/h (145 mph). It caused, at least, US$2 billion in damage and killed 6 people. It also affected Jamaica, the Cayman Islands, The Yucatán Peninsula, the Gulf Coast, Southeastern and Northeastern United States.  

Hurricane Delta, Across the Western Caribbean Sea – Oct 6, 2020

Epsilon – 19 to 26 October, impacted Bermuda minimally, passing about 190 to its east. It had peak sustained winds of 185 km/h (115 mph), making it a Category 3 hurricane. Exact damage to date is unknown but it generated moderate to large swells across most Atlantic coastlines of the Caribbean, the Bahamas, the United States and Canada.

Hurricane Epsilon, Passing Northeast of Bermuda, Oct 23, 2020

Zeta – 24 to 30 October, became the record-tying sixth hurricane to make landfall on the United states in one year. It was also the record fifth named storm to make landfall on Louisiana in one year. Zeta had peak 1-minute sustained winds of 175 km/h (110 mph) and caused eight fatalities and over US$13.7 million in damage across Jamaica alone. It also impacted the Cayman Islands, Central America, the Yucatán Peninsula and the Mid-Atlantic United States.  

Hurricane Zeta Across the Western Caribbean Sea – Oct 26, 2020

Eta – 31 October to present, became the record-tying 28th named storm for the year, placing 2020 level with 2005 for highest number of named storms. Eta is currently a Category 1 hurricane with the potential to reach Category 3 intensity. It is an extreme threat to Nicaragua and Honduras with the potential to cause Catastrophic damage.

Hurricane Eta Across the Western Caribbean Seas – Nov 2, 2020

The month also produced Tropical Storm Gamma – 2 to 6 October. Gamma made landfall on the Yucatán Peninsula with peak 1-minute sustained winds of 110 km/h (70 mph), killing 7 with the damage amount presently unknown.  

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The Hurricane Season in October Not Over

9 10 2020

Dale C. S. Destin|

According to the old mariner’s poem, which attempts to describe the hurricane season, it says October all over, suggesting that the Hurricane season ends by the time October comes around. However, this may be a rhyme of convenience or perhaps the author and the publisher of the famous poem are from a place that never saw tropical cyclones in October, as the hurricane season in no way, shape or form ends in October. October – not over!

Already the month has produced two named storms – Gamma and Delta, with Delta currently a Category 3 hurricane over the Gulf of Mexico, threatening the Gulf Coast States of the US.

Major Hurricane Delta – October 9, 2020

Tropical storms, including hurricanes, are no strangers to the Caribbean in October. Here in Antigua and Barbuda, we have been affected by at least 16 named storms since 1851 – 5 were hurricanes, 2 of which were major hurricanes. Our last hurricane was Gonzalo of 2014, which rapidly intensified just east of us and caught many persons off guard. Damage to Antigua and Barbuda amounted to about US$40 million.

Gonzalo also impacted the rest of the Leeward Islands, Puerto Rico, Bermuda, Newfoundland, the United Kingdom and Europe. In the end the fatalities amounted to six and damage was over US$317 million.

Hurricane Gonzalo over the Leeward Islands – Oct 13, 2014

The Atlantic Basin, including the Caribbean, in October, averages around two named storms, including one hurricane and a major hurricane – Category 3 or higher, every three to four years, based on the current climatological period of 1981-2010. These numbers have already been tied, with well over half of the month remaining.

Category 5 hurricanes are relatively rare for October but not unheard of. On average, the month sees a Category 5 hurricane every 10 to 11 years. The last Category 5 October hurricane was Michael of 2018.

Category 5 Hurricane Michael – Oct 10, 2018

The probability of Antigua and Barbuda being impacted by a storm or hurricane, in October, is around 10 percent, based on the 1981-2010 base period. This means that we are affected by a storm or hurricane, in October, every 10 years. The probability of, at least, one hurricane impacting us is the same. With our last October hurricane being Omar of 2014, statistically, we are not due for an October hurricane until 2024. The probability of a major hurricane is 3 percent – one every 33 years, on average.

Since 1851, the Eastern Caribbean has been impacted by around 28 named storms of which 13 were hurricanes and one major hurricane, according to coast.noaa.gov/hurricanes. Over the base period of 1981-2010, there have been around 8 named storms, 4 of which were hurricanes and 1 was a major hurricane. This translates to the Eastern Caribbean having a 23 percent chance of a named storm, 12 percent chance of a hurricane and 3 percent chance of a major hurricane in October. This means that a named storm impacts the Eastern Caribbean, in October, every 4-5 years, a hurricane every 8-9 years and a major hurricane every 33 years, on average.

The probability of a storm or hurricane (named storm or named tropical cyclone) across the western Caribbean, in October, is around 45 percent. Surprisingly, this is greater than the probability – 37 percent, for a named storm, in September, for the same area. Meanwhile, for the central Caribbean for October, this probability is around 26 percent.

October Hurricane Climatology
The zones of origin and tracks of named tropical cyclones (tropical storms and hurricanes) in October during the hurricane season

The last October hurricane to impact the Caribbean was Michael of 2018 – it impacted Cuba as a Category 2 hurricane and then when on to become a Category 5 hurricane just before making landfall on Florida Panhandle. Michael also impacted Central America, causing deaths across Honduras, Nicaragua and El Salvador. All toll, it caused 43 fatalities and over US$25 billion in damage.

From 1851 to 2019, October has produced a total of 348 named storms of which 207 hurricanes and 46 major hurricanes. For the climate period 1981-2010, there have been 61 named storms with 33 being hurricanes and 9 being major hurricanes.

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It must be noted that there are likely named tropical cyclones (tropical storms and hurricanes) that were missed prior to the satellite era – before the mid-1960s.

October 1950 holds the record for the most named storms for the month – eight. Meanwhile, October 1870 is the record holder for the most hurricanes for the month – six. Further, October has frice produced a maximum of two major hurricanes – 2005, 2001, 1950 and 1894.

What will this October-not-over bring? Thus far, it has already tied the average numbers for the month. Given that each month of the hurricane season has produced, at least, 1.5 times its average number of named storms and that up to 32 named storms are forecast for the year, with 25 gone, this October could end up producing another five storms of which all could become hurricanes and four reaching Category 3 or higher intensity.  

Now you can see why it should be called October not over, as opposed to October all over. Only about 20 times in 169 years there has been no storms in October and only twice for this millennium, thus far.

Please continue to follow me for more on the hurricane season and all things weather and climate via TwitterFacebook and Instagram. Also, share this blog, if you found it useful. Stay prepared!





September Remember 2020 Hurricane Summary

4 10 2020

Dale C. S. Destin|

It was a wild, record-setting September to remember. There was a record nine named storms that formed in the month, breaking the previous record of eight which occurred 2010, 2002 and 1949. Of the nine named storms, four became hurricanes, and one reached major hurricane status – Category 4 Teddy. Juxtapose that with the normal for the month of four named storms, two to three hurricanes and one major hurricane.

This September was so wild, that we exhausted the primary list of names designated to the season, with two more months to go. Thus, the backup list is now in use only for the second time on record. So, the season has gone Greek i.e. storms are now being given names based on the Greek Alphabet. The only other time the season went Greek was 2005 and it did so over a month later than this season – October 22, when Beta of that season formed.

The exhausted primary list of names for named storms for 2020
The backup list for storms when there are more than 21 named storms/tropical cyclones

The frantic month has produced as much as or more named storms than 92 full seasons on record dating back to 1851. This is easily and remarkably more than half – 54 percent, of the 169 seasons on record. This includes 2014, 2009 and 1997, which had nine or less named storms.

Every named storm in September was the earliest storm to develop in the Atlantic for their respective letter or number, on record. The records were broken by as many as 34 days.

Interestingly, none of these storms threatened Antigua and Barbuda and the rest of the Eastern Caribbean. The most we got were large swells from Teddy along with some decent downpours from a few of its feeder bands.

Feeder bands from Teddy impacting the northeast Caribbean to include Antigua and Barbuda – Sep 20, 2020
Feeder band from Teddy across Barbuda, Antigua, Guadeloupe and Dominica – Sep 19, 2020

We are through two-thirds of the season, with two more months to go, officially, and we have already seen 23 named stormsthe most through September and the second most on record, for a season. Only 2005 saw more named storms – 28, and this record is in jeopardy, given the trend and my forecast. There have also been eight hurricanes of which two were major hurricanes – Category 3 or over.

Recall that an average season produces 12 named storms, 6 hurricanes and 3 major hurricanes. Thus, this season has produced, thus far, 191 percent of average number of named storms and 133 percent of average number of hurricanes. Thankfully, you may say, major hurricanes are lagging behind.

A season through September normally produces 9 named storms, 5 hurricanes and 2 major hurricanes. Thus, this season through September has produced 256 percent of average number of named storms, 160 percent of average number of hurricanes and 100 percent of average number of major hurricanes.

 

2020 tropical cyclone (tropical depression, tropical storm and hurricane) tracks through September 2020

 Teddy – 12 to 27 September, became the second major hurricane for the season, with peak winds of 220 km/h (140 mph). It impacted Bermuda with minimal storm-force winds and slammed into eastern Canada with Category 1 winds, but as an extra-tropical cyclone. It also impacted the northern Caribbean and the East Coast of the United States with high swells and surfs. The system was responsible for three fatalities.

Teddy southeast of Bermuda – Sep 20, 2020

Sally – 11 to 18 September, became the first hurricane to make landfall on Alabama since Ivan of 2004. It was a very destructive Category 2 cyclone with peak sustained winds of 165 km/h (105 mph). It caused, at least, US$8 billion in damage and killed 8 people. It also affected the Bahamas and Cuba.  

Sally impacting much of the Gulf Coast of the United States – Sep 15, 2020

Paulette – 7 to 16, 22 to 30 September, became the first hurricane to make landfall on Bermuda since “our” Gonzalo of 2014. It had peak sustained winds of 165 km/h (105 mph). Damage to date is unknown but it killed one person. It also impacted the Cape Verde Islands, the East Coast of the United States, Azores and Madeira with mainly swells and surfs. Note that the system died on 22 September and was resurrected September before dying for good 30 September.

Paulette heading for Bermuda – Sep 13, 2020

Nana – 1 to 4 September, made landfall on Belize as a Category 1 hurricane – 120 km/h (75 mph) before moving on to Guatemala but only caused minor damage. Damage is estimated to be, at least, US$10.2 million and there were no deaths.

Nana impacting Belize and other nearby Central American countries – Sep 3, 2020

There were five other named storms that did not reach hurricane status – Rene, Vicky, Wilfred, Alpha and Beta. Beta was the strongest of them with peak sustained winds of 95 km/h (60 mph). Collectively, damage from them were minor; however, they killed three people.

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The Hurricane Season in September Remember

16 09 2020

Dale C.S. Destin|

September is usually the busiest month of the hurricane season and this September is expected to be no less – it’s on a record pace. Already, the first half of September has produced six named stormsNana, Paulette, Rene, Sally, Teddy and Vicky, two shy of the record. Nana, Paulette, Sally and Teddy also became hurricanes.

September 14, 2020

We in Antigua and Barbuda and the rest of the Caribbean have been impacted most in September by tropical cyclones (TCs). Hence, September remember to standby, it is the heart of the hurricane season.

The Atlantic Basin, including the Caribbean, in September, averages around four named storms, including two to three hurricanes and one to two major hurricanes – Category 3 intensity or higher, based on the current climatological standard normal period, 1981-2010. These numbers have already been exceeded, with half of the month remaining.

The month sees a Category 5 hurricane every 5 years, on average; the last one was Lorenzo of 2019.

The last hurricane to impact Antigua and more so Barbuda, in September, was Super Category 5 Hurricane Irma of 2017, which virtually levelled Barbuda; killing one and causing US$160 million in damage and loss.

Super Category 5 Hurricane Irma passing through the Leeward Islands – September 5-6, 2017

Irma also caused catastrophic damage to much of the northern Caribbean from Barbuda to Cuba. Similar devastation also occurred across Florida. All toll, there were 134 fatalities and over US$77 billion in damage.

Irma is the strongest hurricane on record to impact the Eastern Caribbean. Irma also tied with Hurricanes Rita of 2005 and Mitch of 1998 for the sixth strongest hurricane on record for the Atlantic, with respect to sustained winds.

The probability of Antigua and Barbuda being impacted by a storm or hurricane, in September, is around 26 percent, based on the 1981-2010 base period. This means we are affected by a storm or hurricane, in September, every three to four years.

September Hurricane Climatology
The zones of origin and tracks of storms in September during the hurricane season

The probability of us being impacted by at least one hurricane, in September, is 15 percent. This translates to a September hurricane passing within 120 miles of Antigua and Barbuda every six to seven years. Based on the return period, you may be tempted to say that we are not due for a hurricane in September until 2023 or 2024; however, the law of statistics and return period are not that exact.

Antigua and Barbuda have been affected by 24 tropical storms and 26 hurricanes, in September, 15 were major hurricanes – Category 3 and over, based on the 169 year record. Of course, our most powerful September hurricane was Irma; however, our most destructive September hurricane was Category 4 Hurricane Luis of 1995.

Since 1851, the Eastern Caribbean has been impacted by 97 named storms; 46 were hurricanes and 17 were major hurricanes. Over the base period, 1981-2010, there have been 17 named storms, 8 of which were hurricanes and 3 were major hurricanes. This translates to the Eastern Caribbean having a 43 percent chance of a named storm, 23 percent chance of a hurricane and 9.5 percent chance of a major hurricane in September. In other words, there is a storm in September in the Eastern Caribbean every 2-3 years, a hurricane every 4-5 years and a major hurricane every 10-11 years.

The probability of a storm or hurricane (named storm) across the western Caribbean, in September, is around 37 percent. For the central Caribbean, this probability is around 28 percent.

The last hurricane to impact the Caribbean in September was Category 5 Hurricane Maria of 2017. Maria virtually levelled Dominica and Puerto Rico. Other islands in the northeast Caribbean suffered damage of varying degrees.  It directly impacted Dominica by passing over that island. Puerto Rico suffered a similar fate but after Maria had weakened to a Category 4 hurricane. All toll, Maria killed over 3000 people and caused over US$91 billions in damage.

Maria’s eye passing over Dominica 2200 UTC Sep 18 to 1200 UTC Sep 19 2017

Maria is believed to be the deadliest hurricane in Dominica since the 1834 Padre Ruíz hurricane and the deadliest for Puerto Rico since the 1899 San Ciriaco hurricane.

September has produced around 593 named storms of which 406 were hurricanes, 138 were major hurricanes and 15 were Category 5 hurricanes, dating bad to 8151, not including this year. For the climate period 1981 to 2010, there have been 122 named storms of which 75 were hurricanes and 39 major hurricanes.

It should be noted that there are likely storms that were missed prior to the satellite era – before the mid-1960s.

September has trice had a maximum of eight named storms2010, 2002 and 1949. On four occasions, there were 5 hurricanes – 2005, 2000, 1961 and 1955. Further, on one occasion there were four major hurricanes – 1961.

What will this year bring? Thus far, September has produced six named storms and four hurricanes. It is likely that the record for September of eight named storms and five hurricanes being equalled or broken. Whatever it brings, let’s be prepared! Be hurricane strong!

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August Look Out You Must 2020 Hurricane Summary

4 09 2020

Dale C.S. Destin|

Given the current record season, thus far, August look out you must turned out to be surprisingly but happily just above average, in terms of named storms. The month produced five named storms, two of which reached hurricane status and one reached major hurricane intensity. Tropical Storm Laura caused us a little scare during it formative stage, but its impact was nothing more than that of a tropical wave.

There were five named storms for the month: Josephine, Kyle, Laura, Marco and Omar. Laura and Marco became hurricanes – Category 4 and 1 respectively.

We are just halfway through the 2020 hurricane season; notwithstanding, we have seen more storms than were observed in 140 full seasons, on record dating back to 1851. Only 25 of the previous 169 seasons have seen more than 14 named storms – the total through August 31, 2020. An average season produces 12 named storms, 6 hurricanes and 3 major hurricanes.

Like most of the previous storm for the year, those in August were also the earliest in their positions, on record. Thus, Josephine, Kyle, Laura, Marco and Omar were the earliest 10th 11th 12th, 13th and 14th named storms, on record, respectively. This means that there has never been this many storms, this early, in a year. On average, the season through August 31, produces ONLY 5 named storms, two hurricanes and one major hurricane.

2020 tropical cyclone tracks through August 2020

Laura – 20 to 29 August, is the tropical cyclone of the year, thus far. Laura is said to have gained tropical storm status just about 161 km (100 miles) east of Antigua. This categorisation resulted in unavoidable tropical storm warnings being issued for Antigua and Barbuda, the rest of the Leeward Islands, the Virgin Islands and areas further west. However, the system passed through the area with no sustained strong winds – nothing over 41 km/h (25 mph). This did not sit well with many resident and was expressed by way of very harsh criticism of the Met Service. However, criticism would have been worse if the 25 to 75 mm (1-3 in) of rain forecast did not fall.

A very disorganised Laura on the afternoon of August 21, 2020 – questionable if she were a storm, at this time

Laura eventually became very organised, after passing the Leeward Islands. It became a strong tropical storm and cause death and or damage to the Virgin Islands, Puerto Rico, Hispaniola, Jamaica, Cayman Islands and Cuba. The system became a very powerful Category 4, Major hurricane, in the Gulf of Mexico, before ploughing into Texas and Louisiana with 241 km/h (150 mph) winds, causing death and catastrophic damage. In total, Laura killed 51 people and caused damage over US$8 billion and counting.

Laura making landfall on Louisiana as a Category 4 hurricane with winds of 150 mph

Marco – 20 to 25 August, became the fourth hurricane for the year with peak winds of 121 km/h (75 mph). As a tropical storm, it impacted western Cuba with mainly heavy rainfall and, at least, storm-force gusts. Marco became a hurricane in the central Gulf of Mexico but then rapidly weakened to a tropical depression and then dissipated offshore Louisiana. Marco also proved difficult to forecast. The eventual track and intensity were very different for what was forecast.

Josephine – 11 to 16 August, came close to Antigua and Barbuda but did not cause any adverse weather. Peak winds reached 72 km/h (45 mph) before it died north of Puerto Rico.

Kyle – 14 to 16 August, turned out the be perhaps the tamest tropical cyclone for the year. It was short-lived – it formed offshore of the Carolinas, moved east and died within 48 hours of formation. Peak winds were 80 km/h (50 mph)

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Third Wettest July on Record but Droughts Continue

26 08 2020

Dale C.S. Destin|

July was a very wet month for Antigua. It was the wettest month for the year, thus far, by “miles”, the wettest month since May 2019 and the wettest July since 2011 with 177.3 mm (6.98 in) of rainfall. On record, it is the third wettest July dating back to 1928. Notwithstanding the well above normal rainfall, there has been a mixed effect on the droughts started back in April.

Droughts have eased or ended but the drought that matters most – the hydrological drought, continues. A hydrological drought speaks to shortfall on surface or subsurface water supply. In our case, surface catchments, such as Potworks Dam, remain dry or low with ground water levels also remaining low, although improved. Evidence of the continuing hydrological drought can be seen in the continuation of water rationing by Antigua Public Utilities Authority (APUA).

Potworks Dam, our billion gallon water catchment still dry – 24 July, 2020. Picture courtesy Karen Corbin of the Humane Society.

The agricultural and ecological droughts would have, at least, eased significantly or ended, with the bountiful rainfall in July. Meanwhile, the meteorological and socioeconomic droughts have eased to, at least, slight levels.

Normally, we get 100.3 mm (3.95 in) of rain in July. The total of 177.3 mm represents a surplus of 77.0 mm (3.03 in) or 77%. In other words, the rainfall for this July was 177% of normal or average. Only two other times this mark was exceeded, for the month – 2011 and 1963 with 216.7 mm and 224.8 mm (8.53 and 8.85 in) respectively.

The change in our rainfall fortune is linked to warmer than normal sea surface temperatures across the tropical North Atlantic and the transitioning of the Pacific to La Nina conditions.

The very wet July has also brought the rainfall total for the year to near normal. It is unclear what the last four plus months of the year will bring. Models surveyed indicate equal chance of below, near and above normal rainfall for August-December and for 2020.

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Busy Week Ahead for the Caribbean

16 08 2020

Dale C. S. Destin |

Looks like the Caribbean is set for another busy week. There is the potential for two tropical cyclones – tropical depressions, tropical storms or hurricanes, impacting the area.

Tropical Disturbances AL97 (near the Caribbean) and AL96 (near Africa)

It is the start of a new week but the continuation of a record-breaking hurricane season, which could add two more storms to its tally, in days. There are two new disturbances between Africa and the Caribbean, taking aim at the islands.

Satellite picture animation showing the locations of the distrubances

It is uncertain as to whether these disturbances will become tropical cyclones, where they will go and what hazards, they will bring to the area. However, at this time of the year, most disturbances do develop into tropical cyclones, as conditions are generally conducive, like they are currently, bar the dry and dusty Saharan air.

Today, we saw the end of Tropical Storm Josephine, which threatened the area but eventually passed a safe distance north of all the islands.

Tropical Storm Josephine passing by on Saturday afternoon, 15 August, 2020

With Josephine gone, all attention is now on Disturbances AL96 and AL97. They both have a 50 percent chance of formation. And they both have tracks that take them through the Caribbean.

The second of the two systems, AL96, appears to be more of a future threat to the Caribbean, particularly the Leeward Islands. AL97 is perhaps moving too rapidly for much development to take place before reaching the Eastern Caribbean tomorrow; however, it is forecast to slow down in the Caribbean Sea where it will encounter favourable conditions for formation Wednesday.

Most available models have AL97 becoming a tropical storm in 48 hours – Tuesday night/Wednesday
Most available models have AL97 going through the southern Caribbean, at most, as a Tropical Depression

The gold standard of models – the ECMWF IFS or European model is very sweet on AL96. It gives it a relatively high chance of becoming a tropical storm and track towards our “neck of the woods” – the Leeward Islands this upcoming weekend. This week could end similarly to the one just gone – with us under a Tropical Cyclone Alert or worse.

Already for the season, there have been 11 named storms, the most to have ever occurred this early in the year, with the more active half of the hurricane season just getting started. With half of the season to go, only 48 out a total of 169 seasons, dating back to 1851, has seen more storms.

Be prepared! Based on the forecast, the season is likely to produce, at least, nine more named storms, five more hurricanes and three major hurricanes. It is likely to be a very long season.

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Updated Hurricane Season Forecast – August Look Out You Must, 2020

12 08 2020

Dale C. S. Destin |

My “August look out you must” updated forecast for the 2020 Atlantic Hurricane Season is out, and it continues to call for an above normal season, which is likely to be very active/hyperactive – well above normal.

My forecast calls for 26 named storms (up 3), including ArthurBerthaCristobal, Dolly, Edouard, Fay, Gonzalo, Hanna and Isaias, with 10 becoming hurricanes (up 1) and 4 becoming major hurricanes (down 1). The accumulated cyclone energy (ACE) index is forecast to be 218 (up 18). Further, there is a 70% confidence of

  • 20 to 32 named storms;
  • 7 to 15 becoming hurricanes;
  • 3 to 7 becoming major hurricanes and
  • 141 to 305 ACE.

If the forecast materializes, the ACE would be top 8 of all times. And if we use the ACE as an indicator of destructive potential, as some do, it means that the season’s destructive potential would also be top 8 of all times.

To date, the season has produced an ACE of 23.1, more than twice the usual amount for January through July. A normal season produces 106 ACE. Also, there have been nine named storms to date, two of which became hurricanes – over five time the average number of hurricanes of 1.9 and four times the usual number of hurricanes of 0.2. So, it has been a record busy season. Never before in history have we seen this many Atlantic tropical storms this early in the year.

If the forecast materializes, the ACE would be top 8 of all times. And if we use the ACE as an indicator of destructive potential, as some do, it means that the season’s destructive potential would also be top 8 of all times.

To date, the season has produced an ACE of 23.1, more than twice the usual amount for January through July. A normal season produces 106 ACE. Also, there have been nine named storms to date, two of which became hurricanes – over five time the average number of hurricanes of 1.9 and four times the usual number of hurricanes of 0.2. So, it has been a record busy season. Never before in history have we seen this many Atlantic tropical storms this early in the year.

The main reasons for the above normal forecast are the continuation of a much warmer than usual tropical North Atlantic (TNA) and a developing La Niña.

Tropical North Atlantic (TNA) Index – Reds for warmer than usual and blues for the opposite.
Pacific Ocean Niño3.4 – Reds for warmer than usual and blues for the opposite

The greater the likelihood of these two things happening at the same time – August to October, the greater the chances for an above normal season.

There is one thing that may mitigate these developing near perfect conditions for tropical cyclone formation – more than usual Saharan Dust, streaming across the area. If this were to continue, the forecast numbers would be lower. Unfortunately, we have no skill in forecasting the dust beyond a week; hence, we do not know if the dust will continue beyond August and deep into the peak of the months – August to October.

Compared to my forecast, most other forecasts continue to call for an above normal season. However, compared with most other forecasts, my forecast is calling for a much more active season – 34% more, on average.

Accumulated Cyclone Energy (ACE) based on 15 forecasting entities, including 268Weather.

Clearly, we have no control over the numbers for the season. But notwithstanding the forecast, you should always prepare the same each season, as it only takes one hurricane to ruin your year and or life.

This is my last forecast for this hurricane season. My first forecast for the 2021 season will be available around April 10. All the best for the rest of this 2020 season.

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The Hurricane Season in August Look Out You Must

8 08 2020

Dale C. S. Destin |

August is the second most busy month of the hurricane season, behind September. We in Antigua and Barbuda and the rest of the Caribbean have been impacted by tropical cyclones (TCs) – tropical depressions and named storms (tropical storms or hurricanes), many times in August. Hence, “look out you must” act to become hurricane strong.

Storms and hurricanes for August – 1851 to 2019. The 1899 Ciriaco Hurricane highlighted

The Atlantic Basin, including the Caribbean, averages in August: 3 to 4 named storms, including 2 hurricanes and 1 major hurricane – Category 3 intensity or more, based on the current climatological standard normal period, 1981-2010. The month sees a Category 5 hurricane every 7-8 years; the last one was Dorian of last year. Note that we credit TCs to the month in which they were formed.

Super Category 5 Hurricane Dorian in the northern Bahamas – Sep 1, 2019

The last hurricane to impact Antigua and Barbuda, in August, was Hurricane Earl of 2010. The centre of the hurricane passed within 40 km (25 mi) and 89 km (55 mi) north of Barbuda and Antigua respectively. At the time of impacting the islands, Earl was a Category 2 hurricane with maximum sustained winds of 169 km/h (105 mph). 

Category 2 Hurricane Earl with eye just northwest of Anguilla – August 30, 2010

Barbuda likely got close to the maximum impact from Earl. At the V. C. Bird International Airport in Antigua, maximum winds measured were 82 km/h (51 mph) gusting to 105 km/h (65 mph). The damage to both islands amounted to around US$13 million, and there was one fatality.

Earl also caused damage to the rest of the Leeward Islands, the Virgin Islands, Puerto Rico, the East Coast of the United States and Canada. The system caused a total of 8 fatalities and around US$45 million in damage.

The probability of Antigua and Barbuda being impacted by a storm or hurricane, in August, is around 18 percent, based on the current base period of 1981-2010. The probability increases to 38 percent for the active period being experienced by the Atlantic since 1995. This means that we have been impacted by a storm or hurricane every 2 to 3 years since the mid-1990s.

August Hurricane Climatology
The zones of origin and tracks of storms in August during the hurricane season

The probability of us being impacted by a hurricane, in August, is around 6 percent based on 1981-2010 data and around 11 percent for the current active period. This means that we are affected by a hurricane, in August, every nine years.

Antigua and Barbuda have been affected by 22 tropical storms and 18 hurricanes, in august, dating back to 1851. Our most powerful August hurricane was a Category 4 system nicknamed the San Ciriaco Hurricane of 1899. This is the longest-lived Atlantic hurricane on record – 28 days.

Since 1851, the Eastern Caribbean (EC) has been affected by 99 named storms; 37 were hurricanes and 10 were major hurricanes.

Storms to have pass through the Eastern Caribbean in August – 1851 to 2019

The last hurricane to impact the Caribbean in August was Dorian of 2019. It passed through the Windward Islands as a tropical storm, then turned north-northwest and brushed Antigua and most of the Leeward Islands. Dorian became a hurricane over the Virgin Islands. After leaving the Caribbean, it intensified into the second strongest Atlantic hurricane, tied with the Labour Day Hurricane of 1935 and (Wild) Gilbert of 1988, then literally flattened the northern Bahamas, over a three day period, in which it moved at a “snail’s pace”. It left in its wake 84 fatalities, 245 missing and US$4.6 billion. Dorian became the strongest hurricane, on record, to form in August.

Hurricane Dorian with centre near St. Croix, US Virgin Islands – August 30, 2019

The probability of at least a storm or hurricane impacting the EC annually, in August, is 41 percent; the probability of a hurricane is 15 percent and the probability of a major hurricane is 6 percent. It means that the EC is impacted by a storm or hurricane, in August, every 2-3 years; a hurricane every 6-7 years and a major hurricane every 16-17 years.

The probability of a storm or hurricane across the western Caribbean is around 33 percent. For the central Caribbean, this probability is around 26 percent.

August has produced 392 named storms of which 247 were hurricanes, 120 were major hurricanes and 14 were Category 5 hurricanes, based on NOAA. We note that there are likely storms that were missed prior to the Satellite era – prior to the mid-1960s. For climate period – 1981 to 2010, there have been 101 named storms of which 51 were hurricanes and 26 major hurricanes.

August has trice had a maximum of 8 named storms in a given year – 2012, 2011 and 2004. On two occasions, there were 3 hurricanes – 1966 and 1916. Further, on four occasions there were three major hurricanes – 1969, 1933, 1893 and 1886.

Like July, above normal tropical cyclone activity in August normally signals a busy hurricane season. What will this August bring? We can’t be sure, but the forecast is for an above normal to hyperactive season. Whatever it brings, let’s be prepared! Be hurricane strong!

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