Twin Anniversary of Hurricanes Irma and Luis, where do they Stand Among the Worst Hurricanes to Impact Antigua and Barbuda.

6 09 2021

Dale C. S. Destin |

They both struck on September 5-6 after traversing over the warm waters of the Tropical North Atlantic. Twenty-six years to the day Hurricane Luis (1995) almost totalled Antigua and Barbuda; twenty-two years later, four years ago, Hurricane Irma (2017) did similarly to Barbuda.

Twenty-six years to the day Luis overwhelm our islands, with the centre partially passing over Barbuda and within 25 miles (40 km) of Antigua. Four years ago today, the date of Irma evoked memories of Luis, but it was no Luis.

Irma set a virtually unreachable bar for strength, but Luis set the record for size and cost. Luis was a great big giant while Irma was a mighty midget. The diameter of Irma’s hurricane-force winds was less than 75 miles (121 km) with a radius of less than 25 miles south of the centre. Contrastingly, the diameter for the hurricane-force winds of Luis was at least twice Irma’s, over 150 miles (241 km), with the hurricane force-wind extending about 50 miles (80 km) to the south.

Hurricane Irma on Sep 5 (top) and Hurricane Luis on Sep 3 (bottom) via NOAA satellites

Strength matters but clearly size matters more. Although both hurricanes took a similar journey through the area, Luis caused hurricane-force winds to reach both Antigua and Barbuda, whereas none reach Antigua from Irma. While in our neck of the woods, Luis had peak sustained winds of 140 mph (225 km/h) and Irma had 180 mph, 129% the strength of Luis but about 50% its size. This is what saved Antigua from the Category 5+++ wrath of Irma.

The actual paths of Hurricanes Irma and Luis courtesy NOAA Historical Hurricane Tracks

Antigua and Barbuda has been impacted by 14 major hurricanes, passing within 69 miles (111 km), on record dating back to 1851. There have been four in the last 26 years–Jose and Irma 2017, Georges 1998 and Luis 1995.

Meteo-France radar image showing the eye of Hurricane Irma passing over Barbuda, about 25 miles north of Antigua, 1:15 am (05:15 UTC) Wednesday Sep 6, 2017

A hurricane that compares well with Irma and Luis is Dog of 1950. Dog, also known as “the great hurricane of the central Atlantic”, came through as a Category 4 hurricane with wind of 130 mph (209 km/h). Its centre passed within 10  miles (16 km) of Antigua and within 15 miles (24 km) of Barbuda. Its powerful eyewall would have impacted both islands, like Luis 45 years later.

Prior to Luis, Dog was considered the most severe hurricane on record in Antigua and Barbuda. The damage caused by Dog amounted to up to US$1 million. In today’s currency, that is equivalent to US$8 million, paling in comparison to the US$100 to US$350 million (US$216 to US$755 million 2021) caused by Luis. Dog’s damage also pales in comparison to that of Irma’s US$136 million (US$153 million 2021). Total damage and loss from Irma were about US$155 million (US$174 million 2021).

Downtown St. John’s, Antigua with piles of galvanize

Irma ranks as the strongest hurricane to pass within 69 miles of Antigua in the record books, which dates back to 1851. Luis ranks sixth and Dog ranks seventh. Interestingly, 9 of the 14 major hurricanes passing less than 70 miles of Antigua and Barbuda occurred in the pre-climate change era–1980. The second and third strongest were in 1899 and 1928 respectively.

Major hurricanes to pass within 69 miles of Antigua and Barbuda 1851 to 2021. Multiply by 1.61 to get km/h
NOAA satellite image showing Barbuda in the eye of Irma 1:45 am (05:45 UTC) Wednesday, 6 Sep 2021

Congratulations to all who survived these hurricane nightmares, which I hate to call anniversaries. Let’s hope we don’t see another Luis or Irma-like major hurricane, which is perhaps wishful hoping. More realistically, let us prepare as much as possible to be hurricane strong i.e. hurricane resilient, so that we are able to put up a better fight to resist the next hurricane be it major or not.

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Correction: In the original blog post published on September 6, 2021, I mistakenly calculated the current day value of the damage and loss caused by Hurricanes Dog, Luis and Irma. I updated the post to fix the mistakes on September 13. Apologies for the miscalculations.





Droughts Remain Slight, Despite Scarce April Showers

31 05 2019

Dale C. S. Destin |

Less than normal April showers fell across Antigua this year. The observed total rainfall of 42.2 mm (1.66 in), makes this April the second driest since 2006. Only 49 percent of the usual April showers fell, the rest added to our rainfall deficit; hence, droughts continue.

The last three-month period – February to April, upon which the assessment of the current intensity of the drought is based, was below normal. The period had 129.5 mm (5.10 in), while the normal amount of rainfall is 193.0 mm (7.60 in).

We remain in a severe meteorological drought, the worst category on our drought scale. However, at the moment, the current intensity remains at slight. Recall that the overall description of the drought is based on the worst intensity achieved during its lifetime; however, over time, the intensity will fluctuate. Severe intensities were observed May-July and June-August of last year.

Potworks Dam as of May 1, 2019 – drying up; picture courtesy Karen Corbin of the Humane Society

Potworks Dam, our billion-gallon surface catchment, has fallen below extraction levels – no potable water is currently available from the Dam. Water rationing is imminent but has been delayed by the presence of a number of desal plants operating in the country.

The nineteen-month period – October 2017 to April 2019, the duration of the drought thus far, is deemed severely dry. The total for the period of 1213.1 mm (47.76 in) is the third lowest on record, for such a period, dating back to 1928. This interval normally gets 1866.9 mm (73.5 in), which means a rainfall deficit of near 35% – over one-third of the usual rain was absent.

Based on the last set of rainfall forecasts from regional and especially international sources, the news remains discouraging for rainfall. Overall, below normal rainfall is likely for the next six months – June to November 2019. Thus, there is every reason to believe that the droughts will not only continue but reintensify. The chance of the droughts ending is, at the very most, 30% or low.

Probabilistic multi-model ensemble forecast of rainfall for June-August 2019, based on 12 global models – 70 to 80% chance of below normal rainfall for Antigua and Barbuda

Early projections have us with a 65 percent chance of being drier than normal for the year, with a 50% chance of the rainfall total being in the bottom 20th percentile of all years. Further, around 929 mm (36.6 in) of rain is forecast for 2019, with a 70% chance it falling in the range 664 to 1264 mm (26.1 to 49.8 in).

On average, our severe meteorological droughts last for around 16 months, but not continuously at severe intensity. At current, the drought is in its 19th month; the longest such drought on record lasted 38 months – Jul 2013 to August 2016.

Keep following me for more on this story and all things weather and climate.





March to August 2018 Climate Outlook for Antigua and Barbuda

30 03 2018

Dale C. S. Destin |

Antigua and Barbuda remains in, at least, a meteorological drought. The latest round of climate outlooks suggest that it is most likely to worsen, over the coming three to six months. Signs of the dry weather is becoming quite evident, with Potworks Dam transitioning from a water catchment to a temporary sesonal desert. Drought is occurring and drought watch and warning are in effect for the medium to long-term.

Potworks Dam, Antigua; Mar 13, 2018; Almost Totally Dry. Image courtesy Karen Corbin of the Humane Society

Potworks Dam, Antigua, Mar 13, 2018; Almost Totally Dry. Image courtesy Karen Corbin of the Humane Society. At its max, it holds a billion gallons of water.

Rainfall and drought

Last month, we indicated that the drought was unlikely to worsen or could come to an end in the next three months. This months, the climate indicators are indicating that the drought will mostly worsen and continue for the next six months, at least.

ProjectedRainfall_Dec 2017-May2018

Based on the latest round of forecasts, we will likely be facing more than a meteorological drought. Other droughts that could be on the way, if not already with us, are agrometeorological, Hydrological, socioeconomic and ecological droughts.

For the medium term: at the end of the nine-month period ending June 2018, a drought watch is in effect, as a moderate drought or worse is possible for Antigua. Meanwhile, for the long-term: 12-month period ending August 2018, a drought warning is in effect, as a moderate drought or worse will most likely be occurring. It is possible this period could experience serious drought.

Temperature

Temperatures, including maximum and minimum, were generally near normal or the usual for the December-February (DJF) period, based on the climate period 2001-2015.

Looking down the road over the period March to May– above to near normal mean maximum temperature is likely. Otherwise, equal chances of  below, near or above normal mean temperature and mean minimum temperature. In other words, the current climate signals do point in any given direction as to what is likely to happen with these temperatures.

For the period June to August, the mean and maximum temperature are expected to be above to near normal or warmer than usual to usual. Meanwhile, temperature is equal chance of below, near or above normal mean minimum temperature.

El Nino Southern Oscillation

The cold phase of El Nino Southern Oscillation (ENSO) – La Nina is evident; however, it will be short-live, as already, it has started to transition back to ENSO-neutral conditions. The transition to the neutral phase is expected to conclude by the end of May, with a 55 percent confidence.

In our part of the world – the Caribbean, a moderate or strong La Nina is almost always welcome, particularly in the summer when it has a usual positive impact on rainfall. The opposite – El Nino, has a negative impact. Fortunately or unfortunately, outside the wet season – July to December, ENSO has little or no effect on our rainfall.

La Nina is also welcome from a temperature standpoint, as it usually bring welcome cooler than normal weather. The reverse is true.

Tropical North Atlantic

Over the past three months, the tropical North Atlantic sea surface temperatures (TNA-SSTs) has gone from warmer than usual to colder than usual. However, overall, for the period November-January, TNA-SSTs were warmer than usual. For the upcoming March-May period, TNA-SSTs will likely be at the usual or cooler than usual for this time of the year. Historically, these temperatures seems not associated with any particular rainfall total for March to May.

Regarding temperature, higher that normal TNA-SSTs are associated with higher than usual temperatures for Antigua and vise-versa.

Both ENSO and TNA-SSTs are pointing toward near to below normal temperatures for Antigua. This is interesting, drought conditions are expected to continue and drought normally comes with warmer than normal weather. Current trend seems consistent with ENSO and TNA-SSTs signals.

See the following links for the full outlooks: CariCOF Newsletter – summary and outlooks for the regionprecipitation outlooks and temperature outlooks.





The 2017 Atlantic Hurricane Season Summary

1 12 2017

Dale C. S. Destin|

The 2017 Atlantic hurricane season came to an end yesterday but will long be remembered for the costliest and one of the most destructive on record. It was also one of the most active hurricane seasons on record, breaking or equalling several records.

Hurricanes Katia (left), Irma (middle) and Jose (right)

Hurricanes Katia (left), Irma (middle) and Jose (right)

The hyperactive season produced 17 named storms, 10 hurricanes, 6 major hurricanes and 223 Accumulated Cyclone Energy (ACE). Overall, it is the seventh most active season on record (based on ACE) dating back to 1851 and the most active since 2005.

AtlanticHUrricaneSeasonSummary

Relative to the normal season of 12 named storms, 6 hurricanes, 3 major hurricanes and 106 ACE, this season had 42% more named storms than normal, 67% more hurricanes than usual, twice the normal number of major hurricanes and over twice the normal amount of ACE.

2017HurricaneSeasonSummaryGraphic

The furious 2017 Atlantic hurricane season left in its wake cataclysmic damage and is now the costliest hurricane season on record with cost amounting to over US$367 billion. The Caribbean contribution to this total is about US$120 billion.

Relative to Antigua and Barbuda

It was the most active hurricane season for Antigua and Barbuda, based on the number and strength of hurricanes passing within 105 nm of the islands. This season marks the first time on record that three major hurricanes passed in such proximity of the country. There have been other times with three or more tropical cyclones but none with three major hurricanes.

For the first three weeks of September, we had a ominous procession of major hurricanes – Irma, Jose and Maria. Irma was the strongest, in terms of sustained winds. The current hurricane scale goes from 1 to 5; however; if there were a 6, Irma would have been a Category 6 – it was super strong with peak sustained winds of 298 km/h (185 mph).

Super-Category 5 Hurricane Irma virtually wiped out Barbuda – damaging or destroying around 90% of buildings. Meanwhile, Antigua got away almost “scot-free” with only storm-force winds causing minimal damage.

Damaged and destroyed properties in Barbuda in the wake of Irma – Sep 6, 2017

Both Antigua and Barbuda dodge the bullets from Jose and Maria. Maria also produced storm-force winds; however, Jose passed without causing any notable winds. Notwithstanding, with Jose passing three days after Irma destroying Barbuda – the whole island had to be evacuated.

The expense to Antigua and Barbuda according to the National Office of Disaster Service (NODS): about US$140 million in damage; around US$20 million in losses and a recovery cost of about US$220 million. Most of the damage took place on Barbuda, where one person died during the passage of Irma.

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. This is the first year on record we have been affected by Category 5 hurricanes – Irma and Maria.

AntiguaHurricaneSeasonSummary

Why was the season so active?

The season was hyperactive because of warmer than normal sea surface temperatures and very friendly atmospheric conditions – deep moisture levels and below normal vertical wind shear. This was especially so from around mid-August to early September.

The absence of an El Nino and conditions trending toward a La Nina also allowed for a more active season than normal.

Did climate change play a part?

There is no scientific evidence to support the notion that climate change had anything to do with the hyperactive 2017 Atlantic hurricane season or any previous hurricane season.

This is not to say that climate will not eventually have an impact on the hurricane season in the future. According to the Intergovernmental Panel on Climate Change (IPCC), climate change will, in the future, cause an overall decrease in the number of tropical cyclones but an increase in the number of major hurricanes.

Other notable records

Irma is the strongest hurricane on record to occur in the Atlantic Ocean – outside the Caribbean Sea and the Gulf of Mexico.

Maintaining peak intensity for 37 consecutive hours, Irma is the only tropical cyclone on record worldwide to have had winds that strong for so long.

Irma tied with 1935 US Labour Day hurricane for the strongest hurricane to ever make landfall in the Atlantic Basin.

September 2017 is the most active month on record for the Atlantic

Ten hurricanes in a row form during the 2017 Atlantic hurricane season – the most consecutive hurricanes on record.

Click here for more records.

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, 2018 – 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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