9th Driest July on Record for Antigua, Droughts Continue

26 08 2018

Dale C. S. Destin |

July 2018 was the ninth driest on record for Antigua dating back to 1928. The last time we had a drier July was 2015, when we recorded our driest year in, at least, 145 years.

July2018

The total rainfall for the month of 39.6 mm (1.56 in) was a meagre 39% of what normally falls – 100.3 mm (3.95 in). Hence, there was a painful 61% rainfall deficit for the month.

From_mod_to_severe_droughtThis was also the third driest July or the third driest start to the wet season since 1977. Only 2015 and 2014 Julys were drier, with 33.3 mm (1.31 in) and 19.3 mm (0.76 in) respectively, in recent times.

The last three-month period – May to July, upon which the assessment of the current intensity of the drought is based, was severely dry. In that time, only 96.3 mm (3.79 in) of rain fell. This is the fourth driest such period on record and the second driest since 1977.

Cumulatively, May, June and July normally yield 273.1 mm (10.75 in) of rain; however, a massive 65% of it did not fall. This means that we are now in a severe meteorological drought, the worst category on our scale. Other droughts are believed to be at similar severity. Recall that there are, at least, five types of droughts.

RainfallForPast24Months_July2018

Rainfall (in) for the past 2 yrs. All periods showing well below or below normal rainfall.

So, overall, we are now in a severe drought that is currently at severe intensity. Last month, it was assessed to be a serious drought that was at moderate intensity. Recall that the overall description of the drought is based on the worst intensity achieved since it started; however, over time, the intensity will fluctuate.

Potworks Dam, with a billion-gallon capacity, has been totally dry for a few months now. The vegetation of the Island continues to struggle badly – grass has ceased growing in some locations. Many fields are bare, with some having large and dangerous cracks. Some animals are said to have perished due to insufficient food and water. These are indicative of the fact that the droughts, not just meteorological, are at severe levels.

Potworks_Dam_Aug22018

Potworks Dam – August 2, 2018. Picture courtesy Karen Corbin – Humane Society

Happily, the full brunt of the droughts continues to be held at bay by the presence of the desalination plants, which are virtually the only source for potable water in the country. Notwithstanding, many impacts are starting to break through. Potable water is being rationed, places have been left without water for days to weeks, at a time, notwithstanding a schedule issued by APUA – the water authority, to provide water to everyone, at least, three times per week.

The ten-month period – October 2017 to July 2018, the duration of the drought thus far, is deemed severely dry. The total for the last ten months of 504.2 mm (19.85 in) is the third lowest on record and the lowest since 2001. The period normally gets 945.1 mm (37.21 in) – nearly twice the amount that fell.

Based on the last set of rainfall forecasts from regional and especially international sources, the news remains discouraging. Overall, below normal rainfall is likely, if not expected, for the next six months – September 2018 to February 2019. Thus, there is every reason to believe that the droughts will continue and likely worsen. The chance of the droughts ending is, at most 30% or low.

SON_Aug2018

Probabilistic Multi-Model Ensemble Forecast of Rainfall For Sep-Nov 2018

On average, our severe meteorological droughts last for around 16 months, but not continuously at severe intensity. Will this one continue for another six months? Very likely, given the climate signals.

The probability of 2018 being a drier than normal year remains high – 75%. The best forecast for rainfall amount for the year is 872 mm (34.3 in) with a 70% confidence of the amount ranging between 658 mm (25.9 in) and 1130 mm (44.5 in). Normally, we get 1206.5 mm (47.5 in) annually.

If you found this article informative, I would be very grateful if you would help it spread by emailing it to a friend, or sharing it on Twitter or Facebook.

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Driest June in Over a Generation for Antigua, Droughts Continue

23 07 2018

Dale C. S. Destin |

June 2018 was the driest for Antigua in 33 years – over a generation. With the median age of the Antiguan population being around 31, most Antiguans have never seen a drier June. Not since 1985 has Antigua experienced a drier start to summer.

Potworks_Dam_Jul6_2018

The total rainfall for the month of 12.7 mm (0.50 in) was a parched 18% of what normally falls – 69.3 mm (2.73 in). Thus, there was an excruciating 82% rainfall deficit for the month.

This was the third driest June on record dating back to 1928. Only 1985 and 1974 Junes were drier with 12.4 mm (0.49 in) and 8.1 mm (0.32 in) respectively. The 12.7 mm for this June has a return period of 34 years i.e. such severe dryness for the month only occurs once in every 34 years, on average.

ModerateMetDroughtUnchangedThe last three-month period – April to June, upon which the assessment of the current intensity of the drought is based, had 128.3 mm (5.05 in), only around half of the normal total of 258.6 mm (10.18 in). This puts the meteorological drought current intensity at moderate, unchanged the previous assessment.

Overall, we are in a serious meteorological drought, but currently it is at moderate intensity. The overall description of the drought is based on the worst intensity achieved since it started; however, over time, the intensity will fluctuate.

Potworks Dam, with a billion-gallon capacity, has been totally dry for a couple of months now. The vegetation of the Island is struggling – grass has virtually ceased growing in some locations. Many fields are bare, with some having large cracks. These are indicative of the fact that the droughts not just meteorological, are at moderate levels or worse.

Happily, the full impacts of the droughts continue to be masked by the presence of the desalination plants; however, impacts are starting to break through. Potable water is being rationed, some places have been left without water for many hours to weeks, at a time. There will be a big press conference this morning by APUA – the water authority, to provide answers to the water problem.

The dry season – January to June, had well below normal rainfall. On a scale of 1 to 100, with 100 being best rainfall situation and 1 being the worst, the rainfall was less than a 10. Only 254.3 mm (10.01 in) or 59% of the normal total of 434.6 mm (17.11 in) fell. It was the 10th driest dry season on record dating back to 1928. Only dry season 2015 was drier since 2004.

RainfallForPast24Months_June2018

Rainfall (in) for the past 2 yrs. All periods showing well below or below normal rainfall.

The nine-month period – October 2017 to June 2018, the duration of the drought thus far, is deemed severely dry. This means that the total is in the bottom 5% of the historical data. Such dryness happens around once every 20 years, on average.

The total for the last nine months of 464.6 mm (18.29 in) is the lowest since 2001 and the third lowest on record dating back to 1928. The period normally gets 845.1 mm (33.27 in).

Based on the last set of rainfall outlooks from regional and especially international sources, the news remains bad for rainfall. Below normal rainfall is most likely for the next six months – August 2018 to January 2019. Thus, there is every reason to believe that the droughts will continue and likely worsen. The chance of the droughts ending is at most 20% or slight.

Prob Multi-Model Ensemble Forecast For ASO_Jul2018

Probabilistic Multi-Model Ensemble Forecast of Rainfall For Aug-Oct 2018

Recall that the current drought started in October 2017 with the intensity at serious levels. On average, serious meteorological droughts last for close to a year, but not continuously at serious intensity. Will it go for another three months? Yes, it is now almost certain that this drought will last for a year or more.

Our confidence of 2018 being a drier than normal year is growing. It has increased from 60% to 75% confidence. The best forecast for the amount of rain for the year is around 855 mm (33.7 in) with a 70% chance of the amount ranging between 625 mm (24.6 in) and 1139 mm (44.8 in). Normally, we get 1206.5 mm (47.5 in) annually.

Accumulations_June2018
If you found this article informative, I would be very grateful if you would help it spread by emailing it to a friend, or sharing it on Twitter or Facebook.

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Drier Than Normal May for Antigua, Droughts Reintensify

28 06 2018

Dale C. S. Destin |

The rainfall for May 2018 was below normal for Antigua. The total of 43.9 mm (1.73 in) was only 42% of what normally falls – 103.6 mm (4.08 in). Thus, there was a 58% deficit of rainfall for the month.

DroughtDial-Slight_to_ModerateThe last three-month period – March to May, upon which the assessment of the current intensity of the drought is based, had 135.1 mm (5.32 in), only 56% of the normal total of 240.8 mm (9.48 in). This puts the meteorological droughts current intensity at moderate, declining from slight.

With Potworks Dam totally dry and the vegetation of the Island struggling, there is little doubt that most other droughts are at moderate levels or worse. Happily, the full impacts of the droughts continue to be masked by the presence of the desalination plants.

The eight-month period – October 2017 to May 2018, the duration of the drought thus far, is deemed severely dry. This means that the total is in the bottom 5% of the historical data; such dryness is unusual – it happens, at most, once every 20 years, on average. The total for the period of 451.9 mm (17.79 in) is the lowest since 2001 and the fourth lowest on record dating back to 1928. The period normally gets 775.7 mm (30.54 in).

TemporalRainfall

Based on the last set of rainfall outlooks, the news is not good for rainfall. Overall, below normal rainfall is most likely for, at least, the next three months – July to September. Further, recent outlooks from global models indicate that the next six months will see below normal rainfall. Thus, there is every reason to believe that the droughts will continue and likely worsen.

The rainfall total for the year thus far – January to May, is well below normal. The 365.3 mm (14.38 in) is only 66% of what normally falls. Of the 91 years on record, only 17 have been drier to this point.

RainfallAccumulations_May2018

Even if the rainfall total turns out to be near average, it will not be enough, especially with respect to the hydrological drought, as the monthly evaporation rates will significantly exceed rainfall totals for most of the upcoming months. The chance of the droughts ending is around 20% or slight.

Recall that the current drought started in October 2017 with the intensity at serious levels. On average, serious meteorological droughts last for close to a year, but not continuously at serious intensity. We have just passed the eight-month mark. Will it go another four months? The answer still looks more like to be yes than no.

If you found this article informative, I would be very grateful if you would help it spread by emailing it to a friend, or sharing it on Twitter or Facebook.

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No End in Sight for Drought-Hit Antigua

22 06 2018

Dale C. S. Destin |

There is no end in sight for the current drought affecting Antigua. Not only there is no end in sight but it is expected to get worse, perhaps much worse.

Potworks Dam, a Billion Gallon Dam - Jun 5, 2018.

Potworks Dam, our billion gallon dam, is empty. Pic taken Jun 5, 2018, courtesy Karen Corbin – Humane Society.

Analyses done for the upcoming months, for as far as the (forecasting) eyes can see – through December 2018, suggest a moderate drought or worse will continue. For the drought to end, we need a very wet month or a few months of above normal rainfall – it’s possible but highly unlikely, based on projected climate signals.

LikelihoodOfRainfallForAntigua

The period with the highest likelihood of getting less than usual rainfall is July to September. It is near 100% certain that this period will be, at least, moderately dry i.e. rainfall in the bottom 20% of the historical record. This means that such dryness occurs no more than once every five years.

Already, June 1-20 is tied for the second driest across some parts of the island in over a generation. Further, the year, thus far, is the driest since 2015 and the second driest since 2003.

Meanwhile, the rainfall for the year has a 60% chance of being below normal. The projection is for the year to get around 965 mm (38 in) with a 70% likelihood of it being in the range 686 to 1295 mm (27 to 51 in).  On average, Antigua gets 1194 mm (47 in).

Rainfall For Anu 2018

Ongoing or potential impacts of the drought include the following:

  • Crop or pasture damage or losses
  • Decreased food production and crop scarcities
  • Financial losses primarily to farmers and related sectors
  • Water shortages and restrictions
  • Higher than usual grass and bush fires
  • Environmental degradations

The current and projected dry weather is largely due to the ongoing cooler than normal tropical North Atlantic, which is projected to remain this way through much of the rest of the year. The dryness could be intensified by El Nino, which is now likely to develop by October.

Recall that drought is not the absence of rainfall but rather lower than usual rainfall or a deficit in rainfall. Thus, relatively dry weather conditions will prevail for the drought period.

If you found this article informative, I would be very grateful if you would help it spread by emailing it to a friend, or sharing it on Twitter or Facebook.

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Usual Rainfall for April, Droughts Eased

31 05 2018

Dale C. S. Destin |

The rainfall for April 2018 was near normal; however, is the driest April since 2015. The island-average total for the month was 71.6 mm (2.82 in). This represents 84% of the usual amount of 85.6 mm (3.37 in).

Potworks_Apr282018

The last three month period – February to April, upon which the assessment of the current intensity of the drought is based, had 126.2 mm (4.97 in), 65% of the normal total of 193.0 mm (7.60 in). This puts the meteorological droughts current intensity at slight, improving from moderate. With Potworks Dam about to go totally dry and the vegetation of the Island struggling, there is little doubt that most other droughts are at moderate levels or worse. Happily, the full impacts of the droughts are being masked by the presence of the desalination plants.  According to the Antigua Public Utilities Authority, around 85% of all potable water is coming from the sea via reverse osmosis and is expected to climb to near 90% in days.

The seven-month period – October 2017 to April 2018, the duration of the drought thus far, was seriously dry. The total for the period of 407.92 mm (16.06 in) is the lowest since 2001 and the eighth lowest on record dating back to 1928.

RainfallDeficitGraphic_April2018

Based on the last set of rainfall outlooks, the news is not good for rainfall. Overall, below normal rainfall is most likely for, at least, the next three months – June to August. Additionally, the projected rainfall for 2018 is below normal with a 60% confidence. Thus, there is every reason to believe that the droughts will continue and likely worsen.

Even if the rainfall total turns out to be near average, it will not be enough, especially with respect to the hydrological drought, as the monthly evaporation rates significantly exceeds rainfall totals for most of the upcoming months. The chance of the droughts ending is around 20% or slight.

Recall that the current drought started in October 2017 with the intensity at serious levels. On average, serious meteorological droughts last for close to a year, but not continuously at serious intensity. We have just passed the seven-month mark. Will it go another five months? The answer still looks more like to be yes than no.

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

 





Very Dry March; Droughts Reintensify

26 04 2018

Dale C. S. Destin |

March 2018 was the driest since 2014 and the 12th driest March on record dating back to 1928. The island-average total for the month was 17.8 mm (0.70 in). This represents only 34% of the usual amount of 51.8 mm (2.04 in).

D&P_RainfallGraphic_Mar2018

Rainfall in inches for the past 24 months. Multiply by 25.4 to get mm.

The last three-month period – January to March, upon which the assessment of the current intensity of the drought is based, had 116.1 mm (4.57 in), only 66% of the normal total of 176.0 mm (6.93 in). This puts the meteorological droughts current intensity at moderate, down from slight.

DroughtGraphic: Slight_to_Moderate

With Potworks Dam about to go totally dry and the vegetation of the Island struggling, there is little doubt that other droughts are at moderate levels or worse. Thankfully, the full impacts of the droughts are being masked by the presence of the desalination plants.

Rainfall_Accu_Anu

Interestingly, in a negative way, the rainfall accumulation for the year, thus far, is not very dissimilar to that of 2015 and 1983 – the driest and second driest years on record, respectively. We make no conclusions here but it may be an ominous sign.

The six-month period – October 2017 to March 2018, the duration of the drought thus far, was seriously dry. The total for the period of 326.4 mm (12.85 in) is the fifth lowest on record dating back to 1928. It is also the lowest total for the given period since 2001. The rainfall deficit since the drought started is at 260.1 mm (10.24 in).

Based on the last set of rainfall outlooks, the news is not good for rainfall. Overall, below normal rainfall is most likely for the six-month period April to September. Thus, there is every reason to believe that the droughts will continue and likely worsen.

Even if the rainfall total turns out to be near average, it will not be enough, especially with respect to the hydrological drought, as the monthly evaporation rates significantly exceeds rainfall totals for most of the upcoming months. The chance of the droughts ending is slight – less than 30%.

Recall that the current drought started in October 2017 with the intensity at serious levels. On average, serious meteorological droughts, for Antigua, last for close to a year, but not continuously at serious intensity. We have just passed the six-month mark. Will it go another six months? The answer looks more likely to be yes rather than no.

Keep following us for more on this developing story and all things weather and climate. Follow us here on wordpress and also via twitterfacebookinstagramtumblrflickrgoogle+, and youtube.





2nd Wettest February In Years, Yet Less Than Usual Rainfall

1 04 2018

Dale C. S. Destin|

February 2018 was the second wettest since 2011, yet the rainfall total for the month was below the usual.  The island-average total was 35.8 mm (1.41 in); however, the usual amount for the month is 55.9 mm (2.20 in). Clearly, with only 64% of February’s rains falling, there was no positive impact on the drought situation being experienced.

Slight Meteorological Drought

Rainfall in inches for the past 24 months. Multiply by 25.4 to get mm. For records, the year given marks the start of the period.

The three-month period – December to February, upon which the assessment of the current intensity of the drought is based, had 198.6 mm (7.82 in). This puts the meteorological droughts at slight. However, with Potworks Dam about to go totally dry and the vegetation of the Island struggling, there is little doubt that other droughts are at moderate levels or worse. Of course, and thankfully, the full impact of the droughts is being masked by the presence of the desalination plants.

Drought Level is Slight

Based on the last set of rainfall outlooks, the news is not good for rainfall. Overall, below normal rainfall is most likely for the six-month period March to August. Thus, there is every reason to believe that the droughts will worsen. Even if the rainfall total turns out to be near average, it will not be enough, especially with respect to the hydrological drought, as the monthly evaporation rates significantly exceeds rainfall totals for most of the upcoming months. The chance of the droughts ending is slight – less than 30%.

Recall that the current drought started in October 2017 with the intensity at serious levels. On average, serious meteorological droughts last for close to a year, but not continuously at serious intensity. We have just passed the six-month mark in the drought. Will it go another six months? Unfortunately, the answer looks more like yes than no.

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