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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Flying Start to December’s Rainfall for Antigua

7 12 2014

Dale C. S. Destin |

There has been a flying start to the rainfall total for Antigua for December. So far for the month, December 1-5, the rainfall total at the V. C. Bird International Airport is 50.4 mm (1.98”). This is well above normal, the fifth highest on record dating back to 1967 and the second highest since 1981. Relative to this period, only December 1-5, 2012 has been wetter with 57.0 mm (2.24”), in the past 34 years. On average at the Airport, December 1-5, gets 12.6 mm.

A large portion of the rainfall, so far for the month, was due to a deep layer trough system connected to a low pressure area, which formed hundreds of miles north of Antigua. The trough and low are still around; however, not much more rainfall is anticipated as moisture levels are near minimum.

In 48 years, only four other December 1-5 were wetter: 2012, 1981, 1970 and 1968. The record wettest December 1-5 occurred in 1970, when a staggering 114.0 mm of rain fell.

Dec1-5_Rain_GraphicThis very wet start to December has thankfully further quenched the drought, which started in September 2013; however, it is no yet over. The last assessment of the drought indicates that it has eased to slight levels. At least a further 60 mm would bring it to an end.

Will we get the needed amount of rainfall to end the drought? It is not very clear as the climate continues to send mixed signals. The spike in rainfall over the past couple of months seems to be partially due to warmer than normal North Atlantic sea surface temperatures. However, an El Nino appears to be brewing, and if established, could suppress rainfall. Notwithstanding, the forecasts for December and the period December to February (“winter”) are for above normal to normal rainfall. Thus, it is likely that the drought will end or not get any worse.

Of course, while the 50.4 mm so far for December is impressive and invaluable, it does not tell us where the month will end up overall, and there is a slight chance of the upcoming months having below normal rainfall. On average at the Airport, the rest of December gets 71.2 mm (2.80”) of rainfall. In the past this period has had as little as 14.5 mm (0.57’’) and as much as 207.3 mm (8.16”).

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