Updated Prediction: Below Normal Rainfall Most Likely for Antigua for 2022

31 05 2022

Dale C. S. Destin |

The prediction for rainfall remains discouraging. My latest forecast continues to call for most likely below normal rainfall for Antigua. The most likely total for the year is 1080 (42.5 in), down 25 mm (1 in) from the previous forecast. There is also a 70 percent or high confidence of the rainfall total falling in the range of 590 to 1695 mm (23.2 to 66.7 in).

The main reason for the below normal rainfall forecast is the current trend of cooler than average sea surface temperatures (SSTs) across the tropical North Atlantic (TNA), which should last through summer (June-August). Cooler than normal TNA SSTs favour suppressed rainfall conditions while the opposite enhances rainfall.  

The year started out with a severe drought brought forward. This drought started in the winter of 2020/2021 and continues through the present. This May has been wetter than the last one; notwithstanding, it will end with well below normal rainfall. Year-to-date is drier than normal. Further, since the deluge of November 2020, the start of the current drought, there has been 943.1 mm (37.13 in) of rainfall, for December 2020 to May 2022. This total is so far below normal that it is the second driest such period on record.

The dry season, January to June, is on track to be drier than usual. Summer, June to August, is also likely to be drier than normal. Further, the first three quarters of this year (January to September) is likely to see deficit rainfall with a most likely total of 645 mm (25.4 in) compared to the usual amount of  759 (29.9 in). There is also a 29 percent chance of January to September having top 10 dryness.

WMO Lead Centre for Long-Range Forecast Multi-Model Ensemble is forecasting 40-50% likelihood of below normal rainfall for Antigua and Barbuda for June to August. Also, below normal rainfall is likely for much of the rest of the Caribbean.

A typical year, based on the new standard climate period 1991-2020, averages 1156.7 mm (45.54 in). The dry season averages 410 mm (16.14 in) and the wet season, July to December, averages 746.8 mm (29.40 in). The fall/autumn, September-November, accounts for 58 percent of the wet season total and 38 percent of the year’s total.

This forecast will be updated monthly around the 25th of each month until August. The next update will be issued around June 25.

Regardless of the forecast, we all need to conserve water and be as efficient with its use as much as possible. Reducing our personal water footprint will literally redound to our individual and collective socio-economic benefit. Minimising your water footprint is also good for the climate, good for our environment and good for rainfall.

Please share this blog, if you found it useful, and follow me for more on the evolving drought and for all things weather and climate – TwitterFacebook and Instagram.





May Updated Forecast for the 2022 Atlantic Hurricane Season

17 05 2022

Dale C. S. Destin |

My May updated forecast for the 2022 Atlantic Hurricane Season is out, and it continues to call for a very busy and active season with the potential of being super hyperactive. As of May 18, the forecast is for 20 named storms (down 1), 9 hurricanes (unchanged) and 4 major hurricanes (unchanged).

Recall that the accumulated cyclone energy index (ACE) is the universally accepted metric used to classify the overall activity of a hurricane season. The ACE forecast for this year is 175, 23 above the threshold for an active season, based on 1991-2020 data.

A super hyperactive season like 2017 also remains possible. There is a 33 percent chance of the ACE exceeding 223. Further, there is a 42 percent chance of more than 19 named storms; 27 percent chance of more than 11 hurricanes and also a 27 percent chance of more than 6 major hurricanes.

If the forecast pans out, this season would be the third most active since 2017, in terms of ACE, and the 16th most active on record dating back to 1851. It would also tie with 1933 for the fourth highest number of named storms.  

The survey of other forecasts reveals a consensus for an above normal season. The consensus is for an ACE of 159, 18 named storms, 9 hurricanes and 4 major hurricanes, a busy and active season. This is generally consistent with my forecast. However, regardless of the forecast, you should always be well prepared each season, as it only takes one hurricane to ruin your year and or life.

The ACE forecast from several models, including that of 268Weather’s for April. The overall average is 159

The main reason for the above normal forecasts is the current La Niña, which is forecast to last through the hurricane season, causing favourable conditions for higher than usual tropical cyclone formation.  

Recall, a typical season, based on the new standard climate period 1991-2020, has 14 named storms, 7 hurricanes and 4 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.

This forecast will be updated monthly around the 14th of each month until August. The first update will be issued around June 14.

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

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





What does an Active Hurricane Season Mean for Antigua?

9 05 2022

Dale C. S. Destin |

The early forecast is for the 2022 Atlantic hurricane season to be an active one or above normal. What could this mean for you? Will Antigua be affected by a named storm (tropical storm or hurricane)?

What is an active or above normal hurricane season? This is a season with the accumulated cyclone energy (ACE) index in the top third of the 1991-2020 dataset, or an ACE of 152 or higher. The ACE is a metric that takes into consideration not only the number of named tropical cyclones (subtropical storms, tropical storms or hurricanes) but also their strength and duration.

Given the forecast for an active hurricane season, there is a 43 percent chance/probability of a named storm passing within 105 nautical miles of Antigua or affecting (hitting of brushing) us. This translates into a named storm return period of 2 to 3 active years or a named storm affecting us every 2 to 3 active years, on average. Our last named storm during an active year was Tropical Storm Laura of 2020. This means statistically we are not due one this year, if the season turns out to be active, as forecast.

With an active season forecast, a named storm has a 28 percent probability of affecting us as a hurricane and an 18 percent probability of affecting us as a major hurricane (Category 3 or higher). On average, we get a hurricane passing within 105 nautical miles of Antigua every 3 to 4 active seasons and a major hurricane every 5 to 6 active seasons.

Our last hurricane during an active season, which was also a major hurricane, was Maria of 2017. It did not cause us hurricane winds, but it passed within 105 nautical miles to our southwest, affecting us with storm-force winds. Given we average a hurricane every 3 to 4 active years, and there has been only one active season since then, 2020; statistically, this means we are NOT due for a hurricane this year. Additionally, we are also NOT due a major hurricane this year.

What if a season is not active? For a near normal season, the chance of us being affected by a named storm drops to 23 percent and the chance of that named storm being a hurricane plummets to just 3 percent. If by some miracle, the season is below normal, the chance of a named storm passing within 105 nautical miles from Antigua is 21 percent with a 6 percent chance of it being a hurricane. For non-active seasons, near or below normal, we stand a zero percent chance of getting a major hurricane.

A tropical storm or hurricane not being due does not guarantee one will not occur. The fact that the probability of a named storm in any given year is not zero means that one could occur in any year, despite not being statistically due. An event with a given return period is said to be not due when the average return period has not yet elapsed. Because this is an average return period, the event can happen at any time before or after the return period.

Annually, based on the standard climate period of 1991 to 2020, taking all seasons into consideration, there is a 66 percent chance of a named storm affecting Antigua. Further, there is a 35 percent chance of the named storm being a hurricane and an 18 percent chance of it being a major hurricane.

Tracks of all 31 named storms to have passed within 105 nautical miles of Antigua, 1991 to 2020

Active hurricane seasons are generally not good for us, which may not come as a surprise to you. What may be new here are the relatively high chance of us being affected during such a season, which the forecast is calling for this year.

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








%d bloggers like this: