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.

Follow us for all you need to know about the current drought and all things weather and climate. Follow us on twitterfacebookinstagramtumblrflickrgoogle+, and youtube. Thank you!

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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.

Follow us for all you need to know about the current drought and all things weather and climate. Follow us on twitterfacebookinstagramtumblrflickrgoogle+, and youtube. Thank you!





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.

Keep following us for more on this developing story and things weather and climate. We are available on twitterfacebookinstagramtumblrflickrgoogle+, and youtube





March to August 2018 Climate Outlook for Antigua and Barbuda

30 03 2018

Dale C. S. Destin |

Antigua and Barbuda remains in, at least, a meteorological drought. The latest round of climate outlooks suggest that it is most likely to worsen, over the coming three to six months. Signs of the dry weather is becoming quite evident, with Potworks Dam transitioning from a water catchment to a temporary sesonal desert. Drought is occurring and drought watch and warning are in effect for the medium to long-term.

Potworks Dam, Antigua; Mar 13, 2018; Almost Totally Dry. Image courtesy Karen Corbin of the Humane Society

Potworks Dam, Antigua, Mar 13, 2018; Almost Totally Dry. Image courtesy Karen Corbin of the Humane Society. At its max, it holds a billion gallons of water.

Rainfall and drought

Last month, we indicated that the drought was unlikely to worsen or could come to an end in the next three months. This months, the climate indicators are indicating that the drought will mostly worsen and continue for the next six months, at least.

ProjectedRainfall_Dec 2017-May2018

Based on the latest round of forecasts, we will likely be facing more than a meteorological drought. Other droughts that could be on the way, if not already with us, are agrometeorological, Hydrological, socioeconomic and ecological droughts.

For the medium term: at the end of the nine-month period ending June 2018, a drought watch is in effect, as a moderate drought or worse is possible for Antigua. Meanwhile, for the long-term: 12-month period ending August 2018, a drought warning is in effect, as a moderate drought or worse will most likely be occurring. It is possible this period could experience serious drought.

Temperature

Temperatures, including maximum and minimum, were generally near normal or the usual for the December-February (DJF) period, based on the climate period 2001-2015.

Looking down the road over the period March to May– above to near normal mean maximum temperature is likely. Otherwise, equal chances of  below, near or above normal mean temperature and mean minimum temperature. In other words, the current climate signals do point in any given direction as to what is likely to happen with these temperatures.

For the period June to August, the mean and maximum temperature are expected to be above to near normal or warmer than usual to usual. Meanwhile, temperature is equal chance of below, near or above normal mean minimum temperature.

El Nino Southern Oscillation

The cold phase of El Nino Southern Oscillation (ENSO) – La Nina is evident; however, it will be short-live, as already, it has started to transition back to ENSO-neutral conditions. The transition to the neutral phase is expected to conclude by the end of May, with a 55 percent confidence.

In our part of the world – the Caribbean, a moderate or strong La Nina is almost always welcome, particularly in the summer when it has a usual positive impact on rainfall. The opposite – El Nino, has a negative impact. Fortunately or unfortunately, outside the wet season – July to December, ENSO has little or no effect on our rainfall.

La Nina is also welcome from a temperature standpoint, as it usually bring welcome cooler than normal weather. The reverse is true.

Tropical North Atlantic

Over the past three months, the tropical North Atlantic sea surface temperatures (TNA-SSTs) has gone from warmer than usual to colder than usual. However, overall, for the period November-January, TNA-SSTs were warmer than usual. For the upcoming March-May period, TNA-SSTs will likely be at the usual or cooler than usual for this time of the year. Historically, these temperatures seems not associated with any particular rainfall total for March to May.

Regarding temperature, higher that normal TNA-SSTs are associated with higher than usual temperatures for Antigua and vise-versa.

Both ENSO and TNA-SSTs are pointing toward near to below normal temperatures for Antigua. This is interesting, drought conditions are expected to continue and drought normally comes with warmer than normal weather. Current trend seems consistent with ENSO and TNA-SSTs signals.

See the following links for the full outlooks: CariCOF Newsletter – summary and outlooks for the regionprecipitation outlooks and temperature outlooks.





Drought Eased A Bit For Antigua

2 03 2018

Dale C. S. Destin |

Near normal rainfall for January has eased the drought across Antigua from serious to moderate levels. The island-average rainfall for January was 62.5 mm (2.46 in), 91% of the usual total.

The three-month period – November to January, upon which the assessment of the intensity of the drought is based, had 211.6 mm (8.33 in). It is the second driest such period since 2000 and the 13th driest on record dating back to 1928.

Based on the last set of rainfall outlooks, the news is not good for rainfall. Below to near normal rainfall is expected for the period March to May. Thus, there is every reason to believe that the droughts will worsen or remain the same. There is only a slight chance of them ending over the above mentioned period.

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.

While we can only speak definitively to meteorological droughts, there is little doubt that we are also experiencing agricultural, hydrological and perhaps socioeconomical droughts. These are likely to become more noticeable in the incoming months; however, the full impact will continue to be masked by the presence of desalination plants.

Potworks Dam Feb 13, 2018, Courtesy Karen Corbin - Humane Society

Potworks Dam Feb 13, 2018, Courtesy Karen Corbin – Humane Society

Potworks Dam, the country’s largest catchment with a capacity of around a billion gallons of water, continues to show signs of drying up. Around the middle of February, the water level had fallen to about a quarter or less. It could be totally dry in couple months.

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








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