Potentially Record Low October Rainfall for Antigua

29 10 2016

Dale C. S. Destin |

After a very wet September – the wettest since 1995 and the wettest of any month since October 2012, October 2016 is turning out to be a near record dry October across much of Antigua.

top5driestoctobers

Thus far, the rainfall for Antigua and the V. C. Bird International Airport (VCBIA) are 20.6 mm (0.81 in) and 14.3 mm (0.56 in) respectively. These currently rank as driest and third driest respectively on record dating back to 1928.

Interestingly, the anemic rainfall for the month seems largely due to Hurricanes Matthew and Nicole and Invest 99 Disturbance. Matthew brought us some rain toward the end of September. However, once it passed through the Eastern Caribbean it served as a giant sponge in sucking up all of the moisture in the area and only sharing it with those areas it made unwelcome visits on.

Nicole and to a lesser extent Invest 99 did similarly. Since then, wind shear and high pressure systems have made it difficult to rain across our area.

It is not over yet; we could still end up with respectable rainfall for October. In the past, up to 100 mm (4 in) has fallen in the last two days of the month.

La Nina, which is good for rainfall at this time of the year for our region seems on the verge of developing.

Our experimental monthly rainfall forecast, issued for October, indicated that the month was likely to be wetter than normal; this is very unlikely. However, recent weather forecasts from various weather models are optimistic about rainfall for much of next week, some of which are likely for the last day of the October.

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October 2016 to March 2017 Climate Outlooks for Antigua and Barbuda

24 10 2016

Dale C. S. Destin |

The October 2016 to March 2017 climate outlooks are now available for Antigua and Barbuda. Our worst meteorological (Met) drought on record has come to an end; however, other droughts continue. It is unclear what will happen with respect to rainfall over the next six months as there are equal chances of below, near or above normal rainfall for October-December and January-March. Meanwhile, warmer than normal night-time temperatures are likely to continue.

Potworks Dam, Aug242016 (L) v. Sep62016 (R)

Potworks Dam, Aug 24 2016 (L) v. Sep 6 2016 (R). Pictures courtesy Karen Corbin – Humane Society. 

Drought

After over three years, the rainfall for September 2016 has brought the Met and agrometeorological (AgMet) droughts to an end. However, it was not enough to end the hydrological (Hydro) and socioeconomic (SE) droughts, which continue at slight levels or worse. The island-average of 213.4 mm (8.40 in) for September 2016 is the most for a September since 1995. Further, it is the wettest of any month since October 2012.

Drought Meter

Looking forward – below to near normal rainfall is likely for October-March. Meanwhile, there are equal chances of below, near or above normal rainfall for both October-December (OND) and January-March (JFM). Given these and other forecasts, there is a moderate chance of the country going back into Met and AgMet droughts, and the Hydro and SE droughts re-intensifying in the medium to long-term. Drought watches are in effect.

Rainfall Projection for Jul-Dec2016

El Nino Southern Oscillation (ENSO) – El Nino, is happily becoming a distant memory. There is now a 65% chance of a cold phase i.e. La Nina developing over the next three months.

If you are in our part of the world – the Caribbean, a La Nina would be more than welcome. Unlike El Nino, La Nina often brings us more than usual rainfall. Given our severe water crisis of the past three years, a La Nina is being prayed for.

Precipitation and temperature

Year-to-date, the rainfall for Antigua is 1.3 times more than all the rainfall for 2015. Further, it is the wettest January-September since 2013. Notwithstanding, we are still over an inch in the “red” relative to the long-term average of 792.5 mm (31.2 in).

The recent up-tick in rainfall seems to have flattened-out. There is no clear signal as to rainfall for the upcoming seasons: OND, JFM and October-March. The best forecast is trending toward near to below normal rainfall for the next six months.

The projected rainfall for 2016 is 757.3 to 1336.8 mm (29.8 to 52.6 in) or near to below normal. This is at least 182.0 mm (7.0 in) more than last year’s total. There is only a slight chance of above normal rainfall for the year.

For the period October to March, above normal temperature is likely. Further, night-time lows are likely to continue above normal through OND resulting in continued uncomfortable warmer than usual nights.  Relatively cooler nights are likely for JFM.

The hurricane season

The 2016 hurricane season will go down as the first active season since 2012. Thus far, the current Atlantic hurricane season has produced 14 named storms, 6 hurricanes and 3 major hurricanes.

The accumulated energy (ACE) index which matters most, has shot up to 119% of the average of 106 in less than a month from less than 50%. More than half of this ACE is due to the strength and duration of Major Hurricanes Matthew and Nicole.

In terms of numbers, the forecast for the season is on point as it called for around 15 named storms, 7 becoming hurricanes and 3 major hurricanes.

Notwithstanding the end of the season drawing near, we have been seriously impacted by tropical cyclones in November, recall Hurricane Lenny of 1999. Thus, we need to remain fully prepared, as it only takes one hurricane to set our life and community back by decades. Be prudent: stay prepared for the worst and hope for the best!

See the following links for the full outlooks: October 2016, October-December 2016, January 2016-March 2017October 2016-March 2017Drought, 2016 Updated Hurricane Season Forecast.

The next set of outlooks will be available by November 5, 2016.








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