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.

Click for large image
Click for larger image
Click for larger image

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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July Stand By 2020 Hurricane Summary

1 08 2020

Dale C. S. Destin|

July stand by turned out to be a historic month. This July tied with July 2005 for the greatest number of Atlantic named storms – five, for the month, on record dating back to 1851. It was also the first time since 1996 Antigua and Barbuda experienced sustained storm-force winds.

Tropical cyclone tracks through July 30 courtesy the Weather Channel

The month produced five named storms: Edouard, Fay, Gonzalo, Hanna and Isaias. Hanna and Isaias went on to become Category 1 hurricanes. This is over 450% the usual number of storms for July or 4.5 times the average. Further, the two hurricanes represent 400% the average amount.

We are just one-third the way through the 2020 hurricane season; however, we have seen more storms than what was observed in 80 full seasons. Further, the nine named storms, for the year thus far, are more than or equal to the total storms for 92 individual seasons – more than half of all previous 169 seasons, on record. An average season produces 12 named storms, 6 hurricanes and 3 major hurricanes.

Nine storms down, 8 to 19 more are forecast; the list is likely to be exhausted.

All the storms in July were the earliest in their positions, on record. Thus, Edouard, Fay, Gonzalo, Hanna and Isaias were the earliest 5th, 6th, 7th, 8th and 9th named storms, on record, respectively. In other words, there has never been this many storms, this early, in the hurricane season. On average, the season through July 31, produces ONLY two named storms, a hurricane every other year and a major hurricane every 5 years.

The 2020 season, thus far, has nearly 5 times the average number of storm, nearly four times the average number of hurricanes and over twice the average amount of ACE.

Gonzalo – 21 to 25 July, is one of two storms that impacted the Caribbean. The other storm was Isaias, which formed July 30, went on to become a hurricane and continues at present across the Bahamas and threatening the East Coast of the United States. Gonzalo caused minimal impacts to the southern Caribbean. Meanwhile the impacts from Isaias are ongoing and are expected to be extensive.

Isaias caused sustained storm-force winds across Antigua and Barbuda while it was still Potential Tropical Cyclone (PTC) Nine. In Antigua, peak winds of 69 km/h (43 mph) were recorded at the V.C. Bird international Airport, on July 29, at 07:09 UTC (3:09 am local time). Peak gusts of 82 km/h (51 mph) was recorded at the Sir Vivian Richards Stadium.

Over in Barbuda, PTC caused peak winds 63 km/h (39 mph), which were observed at the Hannah Thomas Hospital, July 29, at 09:54 UTC (5:54 am local time). It also produced peak gusts of 74 km/h (46 mph). The last time Antigua and Barbuda had sustained storm-force winds was 24 years ago from Hurricane Bertha.

PTC Nine also produced 25 to 75 mm (1 to 3 in) of rain, in 36 hours, resulting in minor flooding.

Potential Tropical Cyclone Nine moving across the Caribbean Jul 29, 2020. Antigua and Barbuda circled in yellow

Fay – 9 to 11 July, was the most deadly and destructive of the July storms. It killed six persons and caused US$400 million in damage across Southeastern and Northeastern United States and Eastern Canada.

Hanna – 23 to 27 July, was the second most deadly and destructive. It killed 5 persons and caused over US$395 million in damage. It impacted Hispaniola, Cuba, the Gulf Coast of the United States and Mexico.

Edouard – 4 to 6 July, was the weakest and least impacting of the storms. It affected Bermuda and the British Isles.

While writing this blog, Tropical Depression Ten formed near the coast of Africa. It is forecast to become a storm but not expected to impact any landmass.

Recall that July averages one named storm per year, a hurricane every other year and a major hurricane every 6 to 7 years. Compared to the numbers above for this year, this July was momentous, almost unprecedented.  

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Updated Hurricane Season Forecast – July Stand By 2020

13 07 2020

Dale C. S. Destin|

My “July stand by” 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 hyperactive – well above normal.

My forecast calls for 23 named storms (up 2), including Arthur, Bertha, Cristobal and Dolly, with 9 becoming hurricanes (unchanged) and 5 becoming major hurricanes (unchanged). The accumulated cyclone energy (ACE) index is forecast to be 200 (down 2). Further, there is a 70% confidence of

  • 17 to 28 named storms;
  • 6 to 13 becoming hurricanes;
  • 3 to 7 becoming major hurricanes and
  • 122 to 283 ACE.

If the forecast materialises, the ACE would be top 10 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 10 of all times.

To date, the season has produced an ACE of 7.8, twice the usual amount for January through July 13. A normal season produces 106 ACE. Also, there have been six named storms to date, five time the average of 1.2. 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:

  1. the continuation of a warmer than usual tropical North Atlantic (TNA) and
  2. a developing La Niña.

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 July and into the peak of the season – 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 – 32% 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.

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Drought Deepens…Relief Uncertain

9 07 2020

Dale Destin|

The paltry rainfall for the last three months for Antigua, has caused the meteorological drought to plunge from moderate to severe levels. The rainfall for April-June (AMJ) amounted to only 82.6 mm (3.25 in). This is the sixth driest AMJ on record, dating back to 1928. Further, the rainfall for AMJ represents only meagre 32 percent of the normal total of 274.6 mm (10.81 in). 

Potworks Dam in the background, going on three months, without a drop of its billion-gallon-water capacity. (“Normal” corrected for units Jul 14, 2020)

Other droughts have also tumbled with the meteotological drought, which is considered the mother of them all. These others are at moderate or worse intensity.

The rainfall for June was below normal for the third month in a row. The rainfall of 45.7 mm (1.80 in) was only 66 percent of the normal total for the month of 69.3 mm (2.73 in).

Although drier than normal, it was wetter than the last two Junes combined and more than the last two months combined. This is an indication of just how dry those months were.

Recall that we had very happy first-quarter rainfall. The first three months of the year was wetter than normal. However, since then, things have gone south. Rainfall for the year, thus far, for the dry season – Jan to June, stands at below normal.

The dry season rainfall of 320 mm (12.6 in) amounts to just 74 percent of the normal total of 434.3 mm (17.1 in). It is the driest three-month period since June-August 2018.

The woefully low rainfall since March looks to be mainly due to higher than normal pressure at the lower levels of the atmosphere. This unusual arrangement of pressure resulted in, more often than usual, sinking air, which inhibited warm rising air needed for cloud formation and rainfall.  A record amount of Saharan Dust during June would have also played a huge role in stifling rainfall.

Low level pessure anomaly across the Caribbean Basin and parts of the North Atlantic – April 1 to June 30, 2020. Higher that usual low level pressure inhibits the water cycle and hence, rainfall.
High-level Omega anomaly across the Caribbean Basin and parts of the North Atlantic – April 1 to June 30, 2020. Positive values indicate sinking motion, which is bad for rainfall.

Relief from the drought weather is becoming uncertain. The forecast for July-September (JAS) is for a 45 percent chance of above normal rainfall. This means that rainfall required to bring us out of drought is unlikely.

Looking beyond JAS, my latest forecast calls for less than 40 percent chance of above normal rainfall for the rest of the year, the wet season – July to December. This means that near or below normal rainfall is more likely than drought busting rainfall.  

Considering the whole year, 2020 will most likely be drier than usual. My latest projection is for a 50 percent chance of below normal rainfall, 30 percent chance of the usual rainfall and 20 percent chance of the year getting more than usual rainfall.

How dry it is projected to be? At this time, Antigua’s most likely rainfall for 2020 is 1026 mm (40.4 mm) with a 70 percent confidence that it will fall in the range of 760 to 1349 mm (30 to 53 in). Normally, the island gets 1207 mm (47.5 in).

Projected rainfall for Antigua in inches. There is a 20% chance of it being above normal (A 20%), 30% chance of it being near normal (N 30%) and 50% chance of it being below normal (B 50%). Background pic courtesy Karen Corbin of the Humane Society.

The parched weather was not restricted to Antigua and Barbuda. Much of the rest of the region have been suffering the same fate. There are a few exceptions, most notably is Cuba.

May was a record dry month for Anguilla and St. Thomas. Parts of the Dominican Republic and Belize saw record low rainfall for April. Severe or worse droughts are being experienced in many islands, including Aruba, Barbados, Martinique and St. Lucia.

Rainfall anomaly across the Caribbean Basin – January 7 to July 4, 2020 based on CPC CMORPH

Large scale atmospheric and ocean conditions continue to trend in the direction that would usually cause relief across the Caribbean Basin, including Antigua and Barbuda. However, models continue to not be very enthusiastic about forecasting significant rainfall for much of the region.

The favourable conditions for rainfall for our area are: warmer than usual tropical North Atlantic and cooling of the central to eastern equatorial Pacific i.e. a developing La Nina. Once these two things happen together, we invariably get good rainfall. However, what we can’t predict beyond a week, could negate the positive conditions – Saharan Dust, the x-factor. If it does not let up, it will suppress rainfall and wipe out any optimism in the forecasts for drought-stopping rain.

From all that have been examined, the drought is unlikely to end for the foreseeable future and if it were to, it would only be temporary. This is not to say that we won’t see more rainfall in the second half of the year than the first. We will; however, it is unlikely to end the drought.

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The Hurricane Season in July Stand By

5 07 2020

Dale C. S. Destin|

Unlike June, we have been impacted by tropical cyclones – tropical depressions, tropical storms or hurricanes, in July. Hence, as the 1898 poem by R. Inwards said “stand by” for news of storms that may be coming our way. Notwithstanding, July is still a relatively slow month for tropical cyclone activity.

The last hurricane to impact Antigua and Barbuda, in July, was Hurricane Bertha of 1996. Bertha hit while we were still recovering from one of our busiest hurricane seasons in modern times – 1995, the year of Hurricanes Luis (Category 4) and Marilyn and Tropical Storm Iris.  

139 named storms for July with Hurricane Bertha of 1996 highlighted

The centre of Bertha passed just south of Barbuda, likely causing the island to experience all its 137 km/h (85 mph) winds it was packing, at the time. Passing north of Antigua, the system caused peak sustained winds of only 63 km/h (39 mph). Damage to Antigua was minimal but unclear for Barbuda. Regardless of the damage, the psychological trauma would have been extreme for many, coming 10 months after the horror of Luis.

Bertha also caused damage across the rest of the Leeward Islands, the Virgin Islands, Puerto Rico, the East Coast of the United States and Canada. The system also caused a total of 12 fatalities and at least US$330 million in damage.

Category 3 Hurricane Bertha – July 9, 1996

The probability of us (Antigua and Barbuda) being impacted by a named strom – a tropical storm or hurricane, in July is around 3 percent for all seasons and around 5 percent during the active period being experienced by the Atlantic since 1995. This means that we are impacted by a named storm every 33 years, on average.

The probability of us being impacted by a hurricane is the same as indicated above for named storms. In our history, there have been six named storms of which one was a hurricane – Bertha.

July is also a relatively slow month for tropical cyclone activity, across the Eastern Caribbean. The region has seen 22 named storms, 6 of which were hurricanes and 1 major hurricane – Category 3 Hurricane Emily of 2005, the strongest to pass through the islands in July.

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

Emily is also the last hurricane to impact the Caribbean in July. It passed just north of Tobago, then the centre passed over the southern tip of Grenada. It then travelled west-northwest across the Caribbean Sea, brushing Jamaica as a Category 5 hurricane before slamming into the Yucatan as a Category 4 hurricane.

Satellite image of Category 5 Hurricane Emily south of Jamaica – 16 July, 2005
The track of Category 5 Hurricane Emily – July, 2005

It left death and or damage and destruction in its wake stretching from Trinidad to Texas. One person was killed in Grenada and Honduras, five in Jamaica, Haiti and Mexico, amounting to a total of 17 fatalities. Total damage from Emily was over US$1 billion, with the Caribbean accounting for over US$200 million.

The probability of a hurricane impacting the Eastern Caribbean annually, in July, is 6%. This means that the region gets a hurricane every 16 years, on average. With the last hurricane occurring in 2005, we are one year short of being due one, in July. The probability for a hurricane in July, across the central and western Caribbean is a little higher – 10%.

The zones of origin and tracks of storms in July during the hurricane season

Overall, July averages one named storm per year, a hurricane every other year and a major hurricane every 6 to 7 years. The last named storm and hurricane was Barry of 2019; the last major hurricane was Bertha of 2008 and the last Category 5 hurricane was Emily of 2005.

Based on record since 1851, July has produced 139 named storms of which 66 became hurricanes and 12 became major hurricanes. We note that there are likely storms that were missed prior to the Satellite era – prior to the mid-1960s. For the current standard climate period – 1981 to 2010, there have been 33 named storms, with 16 becoming hurricanes and 5 becoming major hurricanes.

July has had a maximum of 5 named storms in a given year – 2005. On two occasions, there have been 3 hurricanes – 1966 and 1916. Further, on two occasions there were two major hurricanes – 2005 and 1926.

The strongest hurricane on record – Hurricane Allen of 1980, formed on July 31. It slammed Barbados on August 3, with Category 3 winds and Martinique, St. Lucia and St. Vincent, with Category 4 winds. It then reached Category 5 in the Eastern Caribbean Sea before pummelling parts of the Dominica Republic, Haiti, Jamaica and Cuba, on August 6. Allen then reach maximum strength of 306 km/h (190 mph) near the western tip of Cuba, on August 7. Earlier on that day, it severely impacted parts of the Cayman Islands.

Category 5 Hurricane Allen of 1980 – the strongest Atlantic hurricane on record

It goes without saying that Allen left a long trail of death and or damage and destruction from Barbados to Texas. Some damage was catastrophic, for example, St Lucia had 6 fatalities and over US$230 million in damage. Deaths from Allen totalled 269 and damage over US$1.5 billion.

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

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June Too Soon 2020 Hurricane Summary

1 07 2020

Dale C. S. Destin|

June too soon is over, one month down and five more to go for the Atlantic hurricane season. This June had two named storms – Tropical Storms Cristobal and Dolly, the most since 2017. Only four seasons have seen more named storms in June – 1968, 1936, 1909 and 1886.

2020 Tropical Cyclone Tracks Through June 30

Tropical Storm Cristobal became the third named storm for the year – June 1 to 10. It also became the earliest third named storm on record – previous was Tropical Storm Collin of 2016.

Clouds from Tropical Storm Cristobal covering much of Mexico and Central America

Interestingly, Cristobal formed from the remnants of Tropical Storm Amanda. Amanda was the first named storm of the East Pacific hurricane season. It formed on May 30, just south of Guatemala and west El Salvador and moved onshore that area May 31, then rapidly dissipated the same day. That was the end of Amanda but the start of Cristobal.

Together, Tropical Storms Amanda and Cristobal, left a trail of destruction and death caused mainly by torrential rainfall, amounting to up to 1016 mm (40 in), in some areas. The trail runs from Central America to Canada, passing through eastern Mexico, central United States and Canada.

Dolly – June 22 to 24, was a “sheep of a storm”. It formed over the Atlantic, hundreds of miles east of New York and travelled parallel to the east coasts of the United States and Canada, never making landfall.

Upon formation, Dolly became the third earliest fourth named storm in a year, on record. Only Tropical Storm Debby of 2012 and Tropical Storm Danielle of 2016, were earlier. Dolly also became the farthest north forming Atlantic tropical storm, on record, before July 1.

Four down, 13 to 22 more are forecast

Recall that there is a storm in June every other year; one hurricane every 8 years and a major hurricane every 50 years, on average. The month has now gone six years without a hurricane and 54 years without a major hurricane. A good “drought” to have, right?

Recall also the we (Antigua and Barbuda) has never had a storm in June, so the happy streak continues. This is also true for most islands of the Caribbean east of Cuba.

The season is certainly off to a busy record tying start. Thus far, there have been four named storms – Tropical Storms Arthur, Bertha, Cristobal and Dolly. This year ties with 2012 and 1954 for the most named storms by July 1.

Although it was an active June, it may have been more active, if not for record levels of Saharan Dust traversing the tropical North Atlantic, the Caribbean and especially the Western Caribbean and the Gulf of Mexico, the main development regions during June. It was certainly a dust event for the ages.  

Saharan Dust as seen by Goes 16 Satellite at mid day June 23, 2020

So, it’s 30 days down and 152 more to go for the 2020 Atlantic hurricane season. Attention now turns to July stand by. Be prepared, be hurricane strong!

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Saharan Dust to Reduce Air Quality to Unhealthy Levels

20 06 2020

Dale C. S. Destin|

A fresh surge of Saharan Dust is set to reduce the air quality across much of the Caribbean to unhealthy levels on Sunday. The Dust brings with it the potential for wide-reaching health implications from itchy eyes and runny nose to even death.

The presence of particulate matters 2.5 and 10, in the Saharan Dust surge, makes it potentially deadly for sensitive groups people. This includes persons with respiratory or heart disease, the elderly and children.

The unhealthy air quality levels increase the likelihood of respiratory symptoms in sensitive individuals, aggravation of heart or lung disease and premature mortality in persons with cardiopulmonary disease and the elderly.

People who are especially sensitive to the Dust should restrict outdoor activity. Also, keep windows and doors closed, as much as possible, and wear a face mask, rated to filter out PM 2.5, when going outside. Already, we are wearing masks to mitigate COVID-19, these masks are also helpful in mitigating against the health impacts of the Dust.

The caution is for mostly sensitive people. However, there is the potential for the air quality to be worse than forecast and impact everyone in the general population, resulting in increased respiratory illnesses.

The health concerns from the dust is not limited to the impacts of particulate matters. This Saharan Dust is also said to contain bacterial and fungal spores, which can also sicken persons.

Of perhaps even graver concern to health professionals is the chemical content of the Dust. It has been tested positive for such pesticides as polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs) and metals, which are known to very harmful to human health.

Research has also shown that the Dust is also harmful to the health of other creatures. It is harmful to coral reefs by way of the pathogens it contains. The dust is also credited for algae blooms or “red time”, resulting in fish kills and the death of other marine life.

The Saharan Dust is ever-present across the Caribbean but not at constant levels. It gets to us via the prevailing easterly winds, which places the Caribbean downwind from the Sahara Desert. The Dust generally peaks in June and is lowest in December.

Sahara Desert - the Source of the Dust
Sahara Desert – the Source of the Dust

This episode of the Saharan Dust will peak on Sunday at unhealthy levels. However, at present, it is moderate and will return to moderate levels on Monday and continue this way through much of the upcoming week.

Air quality index, as measured at various sites across the Eastern Caribbean Sat afternoon, 20 June 2020
Air quality index, as measured at various sites across the Eastern Caribbean Sun morning, 21 June 2020

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The Hurricane Season in June Too Soon

14 06 2020

Dale C. S. Destin|

We, Antigua and Barbuda, have never had a tropical cyclone – tropical depression, tropical storm or hurricane, in June (knock wood). The same is true for much of the Caribbean east of Cuba.

All 107 Named Storms for June 1851-2019, based on data from NOAA

There has only been one hurricane to impact the Eastern Caribbean in June – Unnamed Category 1 Hurricane of 1933, also called the Trinidad Hurricane. It was a deadly hurricane – killing 13 people in Trinidad, 22 in Cuba and killing, at least, 35 people in total across Trinidad, Venezuela, Jamaica and Cuba. It also caused deaths and destruction across Mexico.

The hurricane season in June for the Caribbean – 1851 to 2019

June averages one named storm (tropical storm or hurricane) every other year; one hurricane every 8 years and a major hurricane – Category 3 or higher intensity, every 50 years, on average. It is the least active month of the hurricane season.

Before this year, the last storm in June was Cindy in 2017; the last hurricane was Arthur of 2014 and the last major hurricane was Alma in 1966.

Given the current season, it may be said that Cristobal, of this June, was overdue by a year; the next June hurricane is due around 2022 and the next June major hurricane is overdue by about 3 years. Will this be the year for what would be the fourth major hurricane for the month? Unfortunately, there are no tools available currently to answer this question.

Interestingly, over the relatively reliable data period of 1966-2019, there is no significant difference in the average number of hurricanes in June for above and below normal seasons. A hurricane forms in June around every five above normal seasons and every four below normal seasons. The mentioned period has no hurricanes in June for normal seasons.

There have been three major hurricanes in June based on record dating back to 1851; however, over the period 1966 to 2019, there has only been one major hurricane – Alma of 1966.

Category 3 Hurricane Alma of 1966 – the most powerful Atlantic June Cyclone along with Hurricane Audrey of 1957

So, what is the probability of a hurricane this June, given an above normal season? It’s around 19 percent. What is the probability for a major hurricane? About 5 percent. For all seasons considered for 1966-2019, the probability of a hurricane and major hurricane is 17 and 2 percent respectively. No significant difference between an above and below normal season.

The zones of origin and tracks of storms in June during the hurricane season

Based on record for 1851 to 2019, there have been, in June, 107 named storms of which 37 became hurricanes and 3 reached major hurricane status – Category 3 intensity or higher. For more reliable data, the period 1966 to 2019 have seen, in June, 37 named storms, 7 becoming hurricanes and no major hurricane. For the current standard climate or base period of 1981-2010, there have been 21 named storms, 4 hurricanes and no major hurricanes.

It turns out that like May, storms in June say nothing about the overall activity for the season i.e. whether it will be above, near or below normal.  

Using the current climate period 1981-2010, if storms are going to form in June, they will mostly do so during the first or last 10 days of the month. Over 80 percent of all storms in June, for the current climate period, forms between June 1-10 or June 20-30.

June on 5 occasions had a maximum of three named storms in a given season – 1968, 1959, 1936, 1909 and 1886. On one occasion it had three hurricanes, 3 Category 2s – 1886. Note: these ALL occurred outside the climate change era. This year could make six years since there was a hurricane forming in the month.

Recall that the forecast is for this hurricane season to be above or well above normal. And notwithstanding what happens in June or any other month, it only takes one hurricane to ruin your year or life. Thus, you need to be prepared as best as possible for every hurricane season.

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Updated Hurricane Season Forecast – June Too Soon 2020

10 06 2020

Dale C. S. Destin|

My “June too soon” 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 hyperactive – well above normal.

The forecast predicts an accumulated cyclone energy (ACE) index of 202 (up 13 over the previous forecast), 21 named storms (up 2 to include Arthur and Bertha), 9 hurricanes (unchanged) and 5 major hurricanes (up 1).

To give a clearer picture of the forecast and the uncertianties, there is a 70% confidence of

  • 17 to 26 named storms;
  • 6 to 13 becoming hurricanes;
  • 2 to 7 becoming major hurricanes – Category 3 and higher and
  • 122 to 289 ACE.

If the forecast materialises, the ACE would be top 10 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 10 of all times.

The main reasons for the above normal forecast are:

  1. the likely continuation of a warmer than usual tropical North Atlantic (TNA) and
  2. the potential for a cooler than normal eastern equatorial Pacific i.e. La Niña.

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.

TNA Index – very positive since about February 2020, indicative of warmer than usual sea surface temperatures across the region

According to other forecasts surveyed, the consensus is for an ACE of 151 (up 5), 17 named storms (unchanged), 9 hurricanes (up 1) and 4 major hurricanes (unchanged). These numbers represent an above normal season.

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

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

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.

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Driest April-May for Over 80 Years

6 06 2020

Dale C. S. Destin|

The combined rainfall total for April and May is near record-breaking low levels for Antigua. The total for this Apr-May: 36.8 mm (1.45 in), is the second lowest on record, dating back to 1928. Only Apr-May 1939, 81 years ago, had less rain – 27.9 mm (1.10 in).

Normally, these months would produce a combined rainfall of 189.2 mm (7.45 in). This means that the rainfall for Apr-May is less than 20% of the normal total, a deficit of over 80%.

Such low precipitation for Apr-May only happens once every 67 years, on average. In other words, there is only a 1.5% chance of this happening per year. Most Antiguans alive today have never witnessed such dryness before, for these months, and are very unlikely to witness it again.

Usually, Apr-May would account for 52% of the rainfall for Jan-May but instead it only accounted for less than 14%. Both April and May had similar extreme deficits. There have been only three other occasions when both months registered less than an inch of rain in the same year – 1973, 1939 and 1928.

It was not long ago that we were enjoying ample rainfall. First quarter rainfall, Jan-Mar, was above normal. However, this wonderful start to the year came to a screeching halt.

The horizontal (flat line) from Apr 1 to May 31 is indicative of the rapid downturn in rainfall as compared to the previous three months.

The difference in rainfall between Jan-Mar and Apr-May is the second greatest on record, indicative of the extremely sharp downturn in precipitation. We went from 237.7 mm (9.36 in) for Jan-Mar to 36.8 mm (1.45 in) for Apr-May, a decline of 200.9 mm (7.91 in). Normally, Jan-Mar and Apr-May produce 176.0 mm (6.93 in) and 189.2 mm (7.45 in) respectively.

Few of us alive today have ever seen this kind of change of rainfall, in Antigua. This kind sharp decline in rainfall from Jan-Mar to Apr-May only happens once every 100 years, on average. Only 1967 has had a greater decline, 240 mm (9.45 in), over the similar month periods.

This Apr-May is also the driest two-month period since May-Jun of 2001. It is also the 12th driest combined consecutive two months on record.

This past April and May were clearly extremely dry, and this dryness was magnified by the preceding wetter than normal first quarter.

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4th Driest May on Record for Antigua

5 06 2020

Dale C. S. Destin|

Potworks Dam, Antigua – June 1, 2020. Currently dry but when full, holds a billion gallons. Pic courtesy Karen Corbin – Humane Society

May 2020 was another very dry month for Antigua. The rainfall total of 20.8 mm (0.82 in) was the lowest since 2001 and the fourth lowest on record dating back to 1928. Only May 2001, 1939 and 1928 have been drier, with May 2001 being the driest with 6.4 mm (0.25 in).

Relative to the normal total for the month of 103.6 mm (4.08 in) only 20% fell; hence, the month had a rainfall deficit of 80%, based on the current base period of 1981-2010.

Such a low rainfall total for May is relatively rare. It happens once every 21 years, on average or has only 4-5% probability of occurring each year.

The rainfall for May is almost “bipolar” – you either get a lot or a little. This makes the rainfall for the month the most unpredictable with the highest variability index of all the months.

The dryness for May was not confined to Antigua. Most of the region from Hispaniola to Trinidad saw, at most, only 25% of the normal rainfall for the month.

The reason for the truant rainfall looks to be due mainly to higher than normal surface pressure and lower than normal relative humidity.  

Rainfall for the year has now fallen to below normal after an excellent start in the first quarter. There are some hopes for the return of seasonal or above seasonal rainfall over the upcoming months. The current forecast is for above normal rainfall for the period June to August.

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Pre-hurricane Season Summary – 2020

1 06 2020

Dale C. S. Destin|

It is June too soon – the Atlantic hurricane season officially starts today. However, it seems like no one remembered to remind the “storm gods” of this fact. Already, we have seen two named storms – Arthur and Bertha, resulting in a very active pre-hurricane season 2020. Only twice on record before, dating back to 1842, that May has produced two named storms – 2012 and 1887.

Arthur formed on May 16, just north of the northern Bahamas. It moved north to near the Outer Banks of North Carolina, then out over the Atlantic and lost its tropical characteristics. It caused tropical storm force winds across a small portion of North Carolina and reached peak sustained winds of 97 kph (60 mph).

Tracks of Tropical Storms Arthur (right) and Bertha (left)

Bertha was a bit of a surprise storm. Formation was not expected due to strong upper-level wind shear. On the morning of 12:50 am, May 27, it was given a 30% chance of formation and by 8:30 am, it was declared a tropical storm with sustained winds of 72 kph (45 mph). It eventually reached peak sustained wind speed of 80 kph (50 mph), before dissipating on May 28. The system caused one death.

In terms of pre-season storms – storms forming between March and May, there have been only four occasions when there were two named storms – 2012, 1951, 1908 and 1887. Of course, I am mindful that before the satellite era – pre mid-1960s, a number of short-lived storms went undetected, resulting in gaps in the record.

On average, there is a storm in May once every 7 to 8 years, based on record for the period 1981-2010, whereas, there is a preseason storm once every 5 years. Most pre-season storms form in May – about 85%, 9% in April and 6% in March.

Preseason storms say nothing about the season they precede, in terms of how active or inactive they will be. However, this season is expected to be active and likely to be hyperactive – well above normal.

We all need to be prepared for the hurricane season regardless of the number of storms and hurricanes being forecast, as it only takes one hurricane to ruin our year or life.

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Tropical Storms in May Mean Nothing

15 05 2020

Dale C. S. Destin |

The first tropical or subtropical storm for the pre-hurricane season is about to form in the Bahamas. Some think that this is a harbinger (sign) for the upcoming hurricane season – June 1 to November 30, but is it?

Tropical disturbance AL90 across the Bahamas with an 80% chance of becoming Tropical Storm Arthur within 48 hours.

To the “naked eyes”, it is understood why some may take a storm forming in May as a sign of bad news for the upcoming hurricane season; however, the numbers don’t agree.

The numbers say that it usually means nothing in terms of the overall activity of the upcoming season. According to NOAA, there have been 29 named storms in May, spread over 27 seasons from 1842 to 2019. Of the 27 seasons, using NOAA’s definitions, nine were above normal (active or hyperactive), 11 were near normal and 7 were below normal (inactive or quiet).

Overall, most seasons with a storm in May, are near normal – 11 times of 27 – 41%. However, from a statistical standpoint, there are no significant differences between above, near or below normal seasons, when there is a storm in May. Hence, a tropical storm forming in the month has no bearing on the activity of the upcoming hurricane season.

Of the 27 seasons with May storms, 9 or 33% was active or above normal; 11 or 41% was normal and 7 or 26% was quiet or inactive

Notwithstanding the above, this hurricane season is expected to be above normal or likely hyperactive – well above normal, see my latest forecast. Clearly, this has nothing to do with the expected formation of Tropical Storm Arthur over the Bahamas.

Further on the tropical cyclone climatology on May, of the 29 named storms to have formed in the month, 5 became hurricanes with none ever becoming a major hurricane. The strongest tropical cyclone of the month occurred in 1863 – a Category 2 unnamed cyclone.

The only Cat 2 May Hurricane on record – Unnamed Hurricane – 1863

On average, there is one storm forming in May every 7-8 years. However, there have been a storm in May of the last 2 years and 6 in the last 10 years. Twice, two storms formed in May of the same season – 2012 and 1887, the most of any. So much for averages, right!

The Eastern Caribbean has never been impacted by a tropical cyclone in May, “knock wood”, based on available record dating back to 1842.

Storms forming in this part of the region in May are not unusual. Of the 29 May storms, 28% have formed or traverse within 300 miles of Nassau, Bahamas.

Unfortunately for the Bahamas, this year they are still recovering from Super Category 5 Hurricane Dorian of September 2019, which levelled much of Northwest Bahamas. You may say that they can’t “catch a break”, as they are about to deal with potentially strong storm-force winds and flooding rainfall, in addition to dealing with the COVID-19 Pandemic.

Possible tracks of what is expected to become Tropical Storm Arthur in 48 hours

May storms mean nothing in terms of the overall activity of the hurricane season; however, they mean a lot with respect to where they impact. Let us be prepared regardless of omens or forecasts for the season – it only takes one hurricane to ruin your year or life.

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