The 2019 Atlantic Hurricane Season Summary

30 11 2019

Dale C.S. Destin|

The 2019 Atlantic hurricane season will come to an end midnight tonight. It will long be remembered for Super Category 5 Hurricane Dorian’s destruction of the northwest Bahamas. The season was also an above normal (or active) one, consistent with my initial forecast issued in April and the updates issued May, June, July and August.

2019 Atlantic basin tropical cyclone tracks.

The active year produced 18 named storms, 6 hurricanes, 3 major hurricanes and over 130 Accumulated Cyclone Energy (ACE). Overall, this year ranks 35 out of 169 on record, dating back to 1851, based on the ACE – the internationally accepted metric for determining the activity of hurricane seasons.

Quite interestingly and unprecedentedly, seven named storms lasted only 24 hours or less. The previous record was six in 2005. Notwithstanding, if this were 40 years ago, many of these short-lived storms would have gone undetected; they certainly would have during the pre-satellite era i.e. before 1966.

My forecast

My best performing forecast for the hurricane season – June 1 to November 30, was the one issued in July, which called for an ACE of 127, with a range of 71-198; 13 named storms, with a range of 9-16; 6 hurricanes, with a range of 4-9 and 3 major hurricane (at least Category 3), with a range of 2-5.

Most powerful and destructive hurricane

Dorian was the most powerful hurricane for this season and many other seasons – past and future. It tied with Hurricanes Wilma of 2005, Gilbert of 1988 and the Labour Day Hurricane of 1935 for second for the most powerful hurricane, based on sustained winds – 295 km/h (185 mph). Only Hurricane Allen of 1990 has had higher winds – 305 km/h (190 mph). However, Dorian became the strongest hurricane, with respect to winds, to make landfall in the Atlantic Basin. In other words, no other land mass in this part of the world, apart from Abaco Bahamas, has ever experienced such high sustained winds.

Dorian about to make landfall on Great Abaco Island , Bahamas – Sep 1, 2019

The season caused over USD 12 billion dollars in damage – the lowest since 2014, with Dorian causing at least 8.28 billion dollars. Of the 8.28 billion, 85% (7 billions) was caused in the Bahamas; this represents around 58% of the total damage for the year.

Hurricane Dorian’s destruction in the Bahamas. Picture courtesy Wikipedia

The death toll is at least 98, with at least 61 dead and at least 400 missing in the Bahamas. The total fatalities for 2019 could be the highest since 2017, when it was over 3300.

Rankings

Looking at the year with respect to the number of named storms – 18. This tied with 1969 for the eighth highest number of named storms for a year. It is the highest number of named storms since 2012.

Ranking of hurricane season by tropical storms (TSs). Graphic courtesy Wikipedia.

The 2019 season is the fourth active season in a row, dating back to 2016; however, 2019 was the least active of the period although it had the highest number of named storms. The main difference is that 2019 had fewer hurricanes.

Relative to the normal season of 12 named storms, 6 hurricanes, 3 major hurricanes and 106 ACE, this season had 50% more named storms than normal but the same number of hurricanes and major hurricanes. The ACE was 23% higher than usual. All metrics indicate that the 2019 season was near or above normal.

Other notable records are:

  • Dorian became the strongest hurricane ever recorded outside of the Caribbean and the Gulf of Mexico – the previous record was held by Hurricane Irma of 2017
  • Dorian impacted the Bahamas for 27 hours as a Category 5 hurricane – the longest ever on record for a Category 5 hurricane to impact one location.

Relative to Antigua and Barbuda

Antigua was brushed by Dorian on August 27, with the system passing about 110 miles southwest of the island. During the passage, it caused wind gusts of 44 to 63 km/h (28 to 39 mph).

The impact on the island was minor, as the system was quite disorganised due to it ingesting dry and dusty air from the Sahara Desert and being battered by hostile wind shear.

On average, Antigua and Barbuda gets one named storm passing within 105 nm every other year, one hurricane every three years and a major hurricane every seven years.

Why was the season active?

The season was active because of warmer than normal sea surface temperatures across the Atlantic and below normal wind shear, particularly during the peak of the seas – August to September.

The absence of an El Nino also allowed for a more active season than normal.

Keep following for more on the just ended hurricane season, tropical cyclones and climate change and all things weather and climate. The next hurricane season starts June 1, 2020 – six months from now, let us all be prepared. Our first forecast for the next season will be issued around April 10.

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Destructive Swells to Impact Much of the Atlantic Basin This Week – Including the Caribbean

27 10 2019

Dale C. S. Destin|

A major swell event is forecast to impact much of the Atlantic Basin this week, including Antigua and Barbuda and the rest of the Caribbean, washed by the Atlantic. The swells are expected to cause high surfs and powerful rip currents, which will be a severe threat to life and property, mainly in the surf zone. There is also the increased likelihood of damage due to flooding of some low-lying coastal areas.

Swells Forecast For Friday Nov 1, 2019

Swells reaching the region are expected to rise to over 3 metres (over 10 ft) and locally or occasionally exceeding 3.5 metres (12 ft), coming out of the northeast. These swells will result in dangerous, life-threatening surfs for beachgoers and other users of coastal areas; hence, advisories and or warnings will be required. Some meteorological services have already issued marine alerts on the event – see information coming out of your national meteorological service for the specifics on this event.

Swells heading our way – Antigua and the Caribbean, have spiked to near 14 feet (4 metres). At periods of 10-15 seconds, it takes 8 to 12 hours for swells to reach us from this buoy/weather station. Please note that we may not see 14 ft swells in the area; however, they are expected to, at least, peak over 10 feet, with higher surfs – causing very hazardous, life-threatening conditions at near-shore/coastals areas. 

The swell event started four days ago by hurricane-force winds associated with an enormaous low-pressure area, which contained Hurricane Pablo and a very powerful extra-tropical cyclone. Since then, Pablo has dissipated and the extra-tropical cyclone ahs transitioned to Subtropical Storm Rebekah. Of course, the extreme weather directly associated with the low never had a chance of reaching the Caribbean and Rebekah likewise has no chance of directly impacting the region.

The Enormous Low-Pressure Area Generating the Swells

The swells in and of themselves are not the real concern. The greater concern is the large breaking swells or high surfs that these swells will caused when they reach the shorelines of the region. Such long period swells can result in surfs as high as twice their heights i.e. in excess of 6 metres ( in excess of 20 ft), in some areas.

Puerto Rico’s Met Service is Forecasting Surfs to Exceed 15 Feet (4.5 metres)
High Surf - Fort James, Antigua
Past High Surf – Fort James, Antigua

The eventual heights of the surfs are largely dependent on the bathymetry (shape and depth) of the near shore coastal areas they interact with. Generally, the shallower the near shore areas, the higher the surfs. The greatest impact will be on the north, northeast and east-facing beaches and coastlines.

The event has started across the northeast Caribbean and will reach the southern Caribbean and South America, including the Guyanas by tomorrow – Monday. A second pulse of dangerous swells will reach the Caribbean by late Thursday. These swells are also forecast to reach the east coast of the United States, Canada and as far away as Greenland, Iceland, the United Kingdom, Europe and Africa.

These high surfs will have the potential impact of injuries or loss of life, beach closures and financial losses. Impacts could also include:

  • disruption to potable water from desalination;
  • salt water intrusion;
  • flooding of low-lying coastal roads;
  • beach erosion;
  • disruptions to near shore marine recreation and businesses;
  • damage to coral reefs and
  • disruptions of marine transportation.

These swells and surfs could result in strong rip currents that can carry even the strongest swimmers out to sea. 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.

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.

There is also concern for those who visit non-beach coastal areas. High surfs can knock spectators off exposed rocks and jetties. Those who rock fish need to pay attention and not expose themselves to this hazard. Breaking waves may occasionally impact harbours making navigating the harbour channel dangerous.

With this event happening during or near a new moon, coastal flooding and erosion are more likely than usual. Coastal flooding from the sea is largely depended on high tides, onshore wind and swell actions.

The potential impacts listed above are just that – potential/possible impacts. I am not saying that they will all definitely happen, but conditions could result in such and past similar swell events have caused such.

If an high advisory is issued for an area – be extremely cautious; bathe only where lifeguards are present. If a high surf warning is issued – do not enter the water. Relatively safe conditions are likely on the opposite, or in this case, the southern sides of the islands.

Swells and associated surfs will peak across the Caribbean tonight and or Monday and again Thursday and or Friday. The highest swells across the region are likely across the northeast Caribbean – Antigua and Barbuda and the rest of the Leeward Islands.

I will keep you updated on this event via TwitterFacebook and Instagram. Please share this blog, if you found it useful and follow me for more on all things weather and climate.

Editor’s note: This post was originally published Oct 27, 2019 and updated on Oct 31, 2019 to reflect changing conditions.





October 8, 1974 Earthquake and Weather Remembered

8 10 2019

Dale C. S. Destin |

October 8, 1974, a clear, cool and calm Tuesday morning, Antiguans and Barbudans had a wakeup alarm of seismic proportion. At 5:50 am 45 years ago today, the region had a powerful 7.5 magnitude earthquake that shattered the day.

1974EQ_Graphic

The October 8, 1974 quake is said to have produced the strongest shaking in several Leeward Islands since the great earthquake of February 8, 1843. It is actually the strongest ever recorded in the Eastern Caribbean, according to UWI, Mona. The 1974 quake was also three times stronger than the Haiti 7.0 magnitute quake of 2010.

A few people are said to have received minor injuries, but no fatality was reported, according to paper – Reconnaissance report of the Antigua West Indies, earthquake of October 8, 1974. The paper also indicated that “damage was confined mainly to larger and older buildings, to a petroleum refinery [West Indies Oil Refinery], and to the deep-water harbour”. 

I was 5 years old back then, to young to remember much. I don’t have any memory of feeling the actual quake, but I do recall quite vividly that when the wooden grocery shop (Bascus Shop – Bennett Street, Villa) next door opened, all the goods were on the floor.

And what was the weather like? A look at the weather records of October 8, 1974 as taken at the V. C. Bird International Airport, Antigua; it was a calm night with mostly clear skies. The mean temperature was around 24 C or 75 F with a relatively cold minimum temperature of 22 C or 72 F.

At the actual time of the quake (5:50 am local time, 1050 UTC), the wind was calm with fair skies (one okta of low-level clouds and four oktas of high-level (cirrus) clouds).  The temperature was a cool 22 C or 72 F and the relative humidity was 96%.

The weather observer also noted that there was a thunderstorm (Cumulonimbus) cloud to the northeast of the Airport but no thunder was observed. Up to October 8, 1974, the rainfall for the month was 89.9 mm (3.54 inches), which is quite a lot for only 7 days. 

Summarizing the night leading up to the most destructive quake on record for the area: it was mostly clear, calm, fairly cool and dry in terms of the absence of rainfall; however, much dew would have formed as the wind was calm all night and the relative humidity in the 90’s.

Questions: What would happen if a similar quake occurred today? Are we better prepared today than we were in 1974? The UWI Seismic Unit has been cautioning that they have seen activities over the past few years similar to the lead up to the 1974 quake; are we heeding this caution?





May’s Showers Ended Droughts

24 07 2019

Dale C. S. Destin |

The mini deluge at the end of May ended the droughts that were being experienced by Antigua, most of which started back in October 2017, after hurricanes Irma and Maria. May 2019 was the second wettest since 2011 and the 15th wettest on record dating back to 1928, with an island-average rainfall of 183.9 mm (7.24 in).

Following a wetter than normal May, June was drier than normal, yielding a meagre 26.1 mm (1.03 in) – only 38 percent of the usual total for the month. Meanwhile, July thus far is running below average, which is not a good sign.

Based on the last set of rainfall forecasts from regional and especially international sources, droughts are likely to return in the upcoming few months – August to October. However, things are looking less challenging for rainfall, as ENSO has returned to neutral state from the rainfall suppressing effects of El Nino.

Probabilistic multi-model ensenble forecast of rainfall for June-August 2019, based on 12 global models – 50 to 60% chance of below normal rainfall for Antigua and Barbuda

Recent projection is for a 50 percent chance of 2019 being drier than normal. This has happily dropped from 65 percent in May, likely, at least in part, due to the dissipation of El Nino. Further, around 1024 mm (41.0 in) of rain is forecast for the year, with a 70% chance of it falling in the range 741 to 1371 mm (29.2 to 54.0 in). The average annual rainfall is 1206.5 mm (47.5 in).

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July’s Update: 2019 Atlantic Hurricane Season Forecast

15 07 2019

Dale C. S. Destin |

My updated forecast for the 2019 Atlantic Hurricane Season is out and it continues to call for above normal activity (an active season) being likely. The probability of this happening is up from the previous forecast from 45% to 54%. Thus, I am more confident of an above normal season.

It calls for an accumulated cyclone energy (ACE) index of 127 (up 13), 13 named storms, 6 hurricanes and 3 major hurricanes.

Forecast parameters with 70 percent confidence intervals in (parentheses), right

A typical season 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.

According to other forecasts surveyed, the consensus is for an ACE of 112, 13 named storms, 7 hurricanes and 3 major hurricanes – above to near normal season. Thus, my forecast is calling for more activity.  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.

The Atlantic hurricane season began on June 1 and will conclude November 30.

The next update will be issued around August 10.

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Hurricane Season History: June

29 06 2019

Dale C. S. Destin|

The first month of the Atlantic hurricane season is coming to a close and the month is yet to see a named storm (tropical storm or hurricane). And as it stands, we are unlikely to see any this June but this is not uncommon.

All 98 Atlantic Named Storms to Have Formed In June – 1851 to 2018

In total, the month has produced 98 named storms on record dating back to 1851; 38 were hurricanes and only 3 were major hurricanes – Category 3 or higher.  

On average, there is a 44% chance of a named Atlantic storm in June, 20% chance of a hurricane and 2% chance of a major hurricane.

In other words, there is a named storm every other June, and hurricane every 5 Junes and a major hurricane every 50 Junes, on average.

From 1851 to present, there have been 75 years with June storms and 93 years without. The June with the most named storms are 2012, 1968, 1936, 1909 and 1886 with three each.

The June with the most hurricanes is 1886. The strongest June hurricane is Alma of 1966 with 205 km/h (127 mph) winds; it did a “number” on Cuba and southeast United States.

The Eastern Caribbean Have Only Had Two Named Storms In June – 1851 to 2018

As the graphic above shows, only three times have we every experienced a named storm across the Eastern Caribbean in June – Tropical Storm Bret in 2017, Tropical Storm Ana in 1979 and an unnamed hurricane in 1933. Bret and the unnamed hurricane impacted Trinidad and Tobago and Ana impacted St. Lucia and Martinique.

Climatological Areas of Origin and Typical Hurricane Tracks for June

Clearly, when storms do form in June, they are likely to develop across the western Caribbean Seas and the Gulf of Mexico – there is very little to no action elsewhere across the basin.

No June Storm has Every Passed Within 120 Miles of Antigua on Record – 1851 to 2018

Quite evident also is that Antigua and Barbuda has never being impacted by a storm or hurricane in June. This may be surprising to many, but it is very much the case and this record is not about to come to an end this year.

This is the second consecutive year no named storm formed in June. The longest streak of no June storm is 7 years – 1947 to 1953. On the other hand, the longest streak of June storms is 8, 2010 to 2017.

Don’t be fouled by a quiet June – it says nothing about the rest of the hurricane season. The probability of an above normal season is similar with or without a named storm in June. Keep your guard up and get or stay prepared. It only takes one storm to ruin your year, if not life.





June’s Update: 2019 Atlantic Hurricane Season Forecast

12 06 2019

Dale C. S. Destin|

My updated forecast for the 2019 Atlantic Hurricane Season is out and it continues to call for above normal activity (an active season) being most likely. The probability of this happening is virtually unchanged from the previous forecast – 45%.

It calls for an accumulated cyclone energy (ACE) index of 114 (up 1), 13 named storms (up 1), 6 hurricanes (down 1) and 3 major hurricanes (up 1). Another way of interpreting my forecast is that it is calling for an above to near normal season – 80% probability.

Forecast parameters with 70 percent confidence intervals in (parentheses), right

A typical season 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.

According to other forecasts surveyed, the consensus is for an ACE of 114, 13 named storms, 7 hurricanes and 3 major hurricanes – above to near normal season, which is now almost identical to my forecast. 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.

The Atlantic hurricane season begins on June 1 and concludes November 30.

The next update will be issued around July 10.

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