Antigua’s Unenviable Record Worst Drought Continues

25 04 2016

Dale C. S. Destin |

Notwithstanding the significant rainfall of the past week, our unenviable record worst drought continues. However, the rains did bring some much-needed relief, as many residents got their cisterns and other catchments replenished. The precipitation also brought some relief to our farming community and landscape.

No sign of water in Potworks Dam, Antigua, April 22, 2016. Photo courtesy Karen Corbin – President of the Humane Society

No sign of water in Potworks Dam, Bethesda, Antigua; April 22, 2016. Photo courtesy Karen Corbin – President of the Humane Society

Recall that there are, at least, four types of droughts – meteorological, agricultural, hydrological and socioeconomic, which is the worst. Antigua has been in these droughts for around two months shy of three years. Of the mentioned droughts, the rains had the greatest impact on the meteorological and agricultural droughts.

For the week ending April 23, the island-average rainfall for Antigua was 63.3 mm (2.49 in). To have ended at least the meteorological drought, we needed over 100 mm (4 in); much more was need to end the other droughts.

Based on a mixture of rain gauge measurements and radar estimates, the rainfall across the island was quite variable, ranging from 25 mm (1 in) in the west to 152 mm (6 in) in the northeast. Notwithstanding, most areas got 40-100 mm (1.5-4 in).

24-hr Estimated Rainfall, From 8 pm April 17, 2016 to 8 pm April 18, 2016

24-hr Estimated Rainfall: From 8 pm April 17, 2016 to 8 pm April 18, 2016

At the V. C. Bird International Airport (VCBIA), the 42 mm that fell on April 18 makes it the wettest day since October 28, 2014. It was also the wettest April 18 at VCBIA since 1992 and 15th wettest of 1620 April days on record since 1962.

VCBIA also had a near record wet spell for April – six consecutive days with at least 1 mm (0.04 in), second only to the seven recorded in 1970. The six-day (April 17-22) total of 70.4 mm (2.77 in) at VCBIA, is now the fourth wettest for the month. With respect to a week, it’s the wettest for April since 2010 and the wettest for all weeks since October 23-29, 2014.

As of Sunday morning, April 24, the island-average rainfall for Antigua for the month was 80.5 mm (3.17 in). Thus far, this is the wettest April since 2013, when we had 132.1 mm (5.20 in). It is also our fourth wettest month since December 2014. On average, April is the fifth driest month with 85.6 mm (3.37 in).

The wet week was all due to a cold front preceded by an associated trough. Both systems have since been replaced by high pressure.

The wet weather has eased the meteorological drought to slight levels; however, not much has changed regarding the more serious hydrological and socioeconomic droughts. Follow us as we continue to monitor our rainfall closely.





The Driest Year for Antigua since at Least 1871

21 12 2015

Dale C. S. Destin |

Earlier this year, we indicated that Antigua could see its driest year on record. Regrettably, this is coming to past. The country is on its way to having the driest year on record dating back to at least 1871 or 145 years ago.

Up to the end of November, the rainfall total stood at 525.8 mm (20.70 in). Based on measured rainfall, it’s the lowest on record for any January-November period dating back to 1928. Further, based on statistical analyses, we are almost 100% certain that this is the driest such 11 months since 1871.

Annual Rainfall for Antigua. Blue line - rainfall; heavy grey line - normal rainfall using base period 1981-2010

Annual Rainfall for Antigua. Blue line – rainfall; heavy grey line – normal rainfall using the base period 1981-2010.

It would take perhaps a miraculous deluge to prevent the 1983 record (681.5 mm or 26.83 in) from being broken. Over six inches of rain is required in December to prevent the record from being broken. Thus far for the month, the rainfall total is less than an inch.

There have been only 11 times in 88 years when the rainfall for December has exceeded 155.7 mm (6.13 in) – the amount required to prevent the record from falling. The probability of this happening is around 12%, El Nino or not. Currently, we are at least 70% certain that this rainfall will not materialize.

We could also see our record driest wet season (July-December). Statistically, there is a very low chance of this happening – around 8%; however, given the near record low rainfall for the month thus far, the chance is increasing.

We do not actually have data from our current stations going back beyond 1928. However, with the use of regression analysis, we were able to use other datasets to successfully extend our record back to 1871. So we now have very high quality datasets of annual and some seasonal rainfall totals dating back 145 years.

Like Antigua, most of the eastern half of the Caribbean could also see record-breaking low rainfall for 2015.

Caribbean Rainfall - Dec 2014 to Nov 2015

Nov 2014-Dec 2015 SPI. The darker the reds, the drier the weather; the darker the blues, the wetter the weather. Record or near record low rainfall for much of the eastern half of the Caribbean basin.

El Nino, Saharan dust and a positive North Atlantic Oscillation are the main culprits for the parched weather conditions for this year.

Keep following this “space” for more insights into the rainfall for Antigua and the Caribbean. Unfortunately, we have additional undesirable statistics to share with you on this subject.





Near Record Dryness for the First Half of May

17 05 2015

Dale C. S. Destin |

The first half of May 2015 is over and the Met Office, located at the V. C. Bird International Airport, Coolidge, Antigua, has measured only 1.7 mm (0.07 in) of rainfall. This represents the second driest such period on record. The only time May 1-15 was drier was back in 2001.

May 1-15 Rainfall at the V. C. Bird Int'l Airport

We are clearly not having a normal May or year but normally we would have received around 37.8 mm (1.49 in) by now. Instead, we have had near record dryness.

The rest of the country has not fared better. In fact, there are a few areas that are yet to see measurable rainfall for the month. Neighbouring islands are also experiencing similar rainfall deficits.

This severe dryness for the first half of May is very rare. On average, this happens once every 250 years, which translates to a 0.4% probability of May 1-15 being this dry.

The near record low rainfall seems largely connected with the anomalous cooling of the tropical North Atlantic which is associated with a positive North Atlantic Oscillation (NAO). Another significant driver of the dryness is the above normal flow of very dry, dusty air from the Sahara Desert to the region.

A dry start to the month does not always imply a dry month; however, of the six other times we have had 10 mm (0.40 in) or less for the first half of May, the eventual month’s total has never exceeded 56 mm (2.20 in). Only once such a dry start did not signal a dry month.

Overall, the second half of May has produced as little as 3.9 mm (0.15 in) and as much as 434.7 mm (17.1 in). Hoping to be wrong, but it would not be “tempting fate” to say that we absolutely will not get anywhere remotely close to 434.7 mm over the next two weeks.

Climatologically, the past 30 years show that rainfall on a whole for May is not changing. However, May 1-15 is trending positively (wet) while May 16-31 is trending negatively (dry). These trends are not considered significant, at the moment, but May 1-15 is not far away from being so.

The driest May on record at the Airport, dating back to 1928, is May 2001 with 7.6 mm (0.30 in). This record appears to be in jeopardy.

Follow us also on @anumetservice, facebook and tumblr for the latest on the current drought and other weather & climate news.





Record Breaking Rainfall over the Past Two Years

29 03 2012

As we continue to see a drying trend across our area, the record shows that the past two years ending February 2012 was the wettest on record. The total for the period March 2010 to February 2012 was 129.80 inches; the previous highest was 129.72 inches recorded over the period March 1951 to February 1953; this was 59 years ago. The normal rainfall for this period is 93.88 inches. Recall that prior to the past very wet period, we had a serious drought during the second half of 2009 through early 2010. We may be heading into another Meteorological Drought over the next few months.








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