Drier than Usual January for Antigua

23 02 2022

Dale C. S. Destin |

January 2022 was another drier than usual month for Antigua; the fourth in a row and the 10th since January 2021. The month registered just  48.3 mm (1.90 in), making it the fifth January of the last eight with below normal rainfall.

January usually clocks 67.3 mm (2.65 in) of rainfall annually (1991-2020); this means the month fell close to 28 percent below its usual total. This is an improvement over January 2021, when the deficit was close to 60 percent. Notwithstanding, it is another year with a bad start.

January’s rainfall anomaly (deviation from normal) in percentage (blue line) along with the long-term trend (grey broken line). The background is that of Potworks Dam, 3 February, 2022

The rainfall for January continues to trend negatively (downward); however, this trend is statistically insignificant. The trend is at a rate of just 0.16 mm (0.0064 in) per year or 16 mm (0.64 in) per hundred years. This also represents an insignificant rate of 0.24 percent per year or 24 percent in 100 years. No evidence of a changing climate with respect to rainfall in January.

In aggregate, the three-month period ending January is among the driest on record going back to 1928. The total of 141 mm (5.55 in) is the third lowest behind November-January of 1967/68 and 1947/48. The last four, five, six and seven-month periods ending January had record-breaking low rainfall. Further, the last year (February to January) ranks second driest, on record, with 621.5 mm (24.47 in). The record is 588 mm (23.15 in), February 2015-January 2016.

Clearly, we remain in the grips of a severe meteorological drought, which is also defined as exceptional by some other metrics. Also evident are agriculturalhydrologicalecological and socio-economic droughts, at varying intensities. Potworks Reservoir remains 100 percent empty, converted into a pasture for grazing animals. All other surface catchments are in a similar state or below extraction levels.

Antigua Public Utilities Authority (APUA), the country’s water resource manager, has just commissioned a new reverse osmosis plant to obtain more potable water from the sea. This should bring the daily total from this source to over 7 million and it should help to ease the water woes. However, the drought continues to be a very serious matter for many, who are forced to go days without potable water, as demand continues to outstrip production by hundreds of thousands of gallons.

The drier than usual start to the year was not confined to Antigua. Much of the Caribbean Basin experienced below normal rainfall with some islands or part thereof getting less than 25 percent of their usual total–75 percent rainfall deficit or more.

CMORPH 1-Month Percent of Normal Rainfall for January 2022

Drought conditions have worsened across a number of the other islands, including the rest of the Leeward Islands, the Virgin Islands and Puerto Rico, most of the Windward Islands and Barbados. The Caribbean Institute for Meteorology and Hydrology (CIMH) has recommended drought watches or warnings for most islands of the Caribbean.

It is unclear as to when there will be any notable respite from the drought. The latest set of models surveyed suggests an equal chance of below, near or above normal rainfall for March to May for Antigua and Barbuda and much of the rest of the Caribbean.

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The Northern Caribbean Set to Experience its Worst Swell Event for the Season

5 02 2022

Dale C. S. Destin |

Strong winds from a low-pressure system, some distance away, are pushing relatively large swells toward the northern Caribbean and the Bahamas, including Antigua and Barbuda and the rest of the Leeward Islands. Swells have started to arrive and will reach warning levels tonight through much of Saturday night.

NOAA Station 41044 – NE ST MARTIN – 330 NM NE St Martin Is showing relatively tall swells heading toward the northern Caribbean

This will be no Swellmageddon but it will be the worst swell event of the swell season: December to April. This event will see swell waves coming from the north-northeast at 2 to 3 metres (7 to 10 ft). Occasionally, they will reach 4 metres (near 13 ft). Though it will be no Swellmageddon, it will not be your garden variety swell event, as surf warnings are required.

Video by Windy.com showing swell heights
The possibility of significant wave heights (SWH) equaling or exceeding 3 metres or 10 feet. This is likely to expected in the northern coastal waters, according to the ECMWF IFS Model.

These swells will be virtually harmless in open waters, but they will be a very different “kettle of fish” when they run up on reefs and exposed northern and eastern coastlines which are relatively shallow and gentle to moderately sloping. In these environs, surfs (breaking swells) could be as much as twice the height of swells, as they crash onto shorelines.

Surfs at Fort James during a past swell/surf event

Such high swells and surfs will produce a high threat to life and property in the surf zone. There is the potential for extensive impacts. High surfs will result in beach closures, as swimming conditions will be extremely dangerous for beachgoers. Not entering the waters of affected areas would be a great safety idea and best advice.

The event will likely cause major beach erosion; possibly flooding of low-lying coastal roads; disruptions to marine recreation and businesses; financial losses and damage to coral reefs.

Although relatively small, this swell episode may also cause disruptions to potable water from desalination, as turbulent seas, will increase the turbidity of the water above tolerable levels for the desalting plants.

A high surf warning has been issued by the Met Office for Antigua and much of the rest of the northeast Caribbean. Other offices, as far west as the Bahamas, are expected to issue requisite marine alerts, if they have not done so already.

Precautionary actions: No one should enter the waters of the main warning areas: northern and eastern coastlines. All are also urged to stay away from rocky and or coastal structures along affected coastlines.

The impact on shorelines will not be the same everywhere. Depending on the depth, size, shape and the natural shelter of the coastal waters, the impact will be different. Shallow north-facing shorelines are expected to see the highest swells and surfs.

Seas are to return to safe levels by Monday morning.

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Relatively Very Wet Weekend Possible for Parts of the Northeast Caribbean

4 02 2022

Dale C. S. Destin |

A cold front looks poised to cause a relatively very wet weekend across much of the northeast Caribbean, including Antigua and Barbuda. Several reliable models are forecasting possible rainfall totals of 25 to 76 mm (1 to 2 in) to fall over the period Friday to Sunday.

Proxy visible satellite image

The potential total of 76 mm in 48 to 72 hours is not in and of itself a high figure. However, relative to February, this is a lot of water. The average rainfall for the second month of the year is 50.0 mm (1.97 in). This means we could welcome more than the average for the month, in a few days.

After this weekend, this February could be the wettest since 2004, ranking among the top 10, on record. Only seven Februarys, on record dating back to 1928, had more than 76 mm (3 in) of rainfall.

GFS model indicating 30-40% chance of more than 25 mm in 24 hours ending 8 am (12 UTC) Saturday, 5 Feb, 2022

If the models prove right, this weekend would easily be the wettest in, at least, 16 weeks and the wettest month in four months. Some parts of the country could see a record wet first week of February. The record for February 1-7, at the Airport, is 54.8 mm (2.16 in), which occurred in 2002. We could also see the 24-hour rainfall accumulation, across some parts of the island, exceed 25.4 mm or one inch, for the first time since 2004 and the fourth time on record.

Notwithstanding the potential for a relatively very wet weekend, this will have minimal impact on the droughts. It will likely have a big impact on domestic catchments but virtually no impact on the island’s catchments.

There is no doubt that these showers would be welcome by all; however, they could prove very disruptive to the ongoing ICC Under-19 Cricket World Cup, which climaxes this weekend, with the final and third-place position. It will likely also be disruptive to other outdoor events.

The system has already caused wet weather across Hispaniola and Puerto Rico with isolated totals of up to 203 mm (8 in). If this amount were to reach us, it would cause absolutely wet conditions and place a dent in the drought, but it is very unlikely that we will get this lucky.

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