‘Drier, hotter’ wet season – CIMH forecast

Drought is expected to drag on through the wet season, especially for Barbados and the rest of the southeast Caribbean – with a September heatwave, says the Caribbean Institute for Meteorology and Hydrology (CIMH).

In its Caribbean Climate Outlook for June to August this year, CIMH said: “Drought is expected to continue into the wet season in areas currently affected, as weak El Niño conditions and less than the usual rainfall are forecast to persist throughout the season.

“More wet spells are expected throughout the region, except in Aruba, Bonaire and Curacao (ABC islands). However, possibly fewer than in most wet seasons. These spells may bring some level of drought relief, but also concern for flooding. Peak heat stress will most likely start in August with heatwaves in most countries.”

“Episodes of Saharan dust incursion are expected,” the Barbados-based weather science centre also warned.

The peak of the Caribbean wet season, from September to November, may be unusually dry for Barbados and the Windward Islands south to Trinidad and Tobago, according to the CIMH forecast.

It will be wetter than usual in the ABC islands, Bahamas, Belize, the Greater Antilles and the Leeward islands, it said.

The CIMH outlook added: “Drought in the southeastern Caribbean may therefore persist, while it may ease up in other affected areas. Nevertheless, the average occurrence of extreme wet spells and corresponding flash flood potential peaks in this season.

“Heat stress will likely peak in September and markedly decrease after October, with warmer temperatures forecast throughout the season and heatwaves probably occurring in many countries.”

An El Niño event tends to tilt the odds to warmer and drier conditions with less rainfall in most parts of the Caribbean, it said.

But the institute added that for the northwestern part of the region, which includes Jamaica, “an El Niño maintaining into November could lessen these impacts” there

CIMH said that for the Tropical North Atlantic and the Caribbean, sea-surface temperatures (SSTs) have remained around the seasonal average since 2019.

It said: “The subtropical areas of the North Atlantic and the Gulf of Mexico have remained up to 1°C above average.

“Sustained warm SST anomalies north of the Caribbean are forecast to remain in place, while Caribbean Sea and [Tropical North Atlantic] SSTs are expected to increase to slightly above average.

“Warm SSTs north of the Caribbean may lead to above-average humidity and atmospheric instability there. Those factors favour a wetter and warmer wet season in the north.”