|Barbados Meteorological Services
Initial to 4 days discussion based on Satellite imagery,BMS Radar composite,S.P.I.E products,GEM, GFS, WW3, UKMET and BMS WRF modeling, surface and upper air observations, Satellite derived products.
DATE: 20170424 PERIOD: Evening
Fair to partly cloudy skies with only a few brief showers, prevailed over Barbados, the central and southern Windward islands today, as a weak surface to low level Atlantic high pressure system remained the dominant feature. Satellite imagery revealed a few shallow low level cloud fragments traversing from St. Lucia southwards to Grenada.
Meanwhile, a surface to low level shearline continued to linger over the Leewards and extreme northern Windward islands. Analysis indicated that this feature also began to merge with a surface to mid level trough currently affecting the Central Caribbean. Subsequently, occasionally cloudy skies with scattered showers was reported over some islands. Radar composite imagery depicted echoes mainly over Dominica, Guadeloupe and further east over open water. Nevertheless, as the day progressed, most of the cloudiness and shower activity was observed dissipating.
Moderate to brisk 11 to 20 knot breezes were generally reported across the region. Furthermore, meteorological observations from Grenada revealed higher gust of 30 knots on two seperate occasions. Seas remained slight to moderate in open water with swells peaking near 2.0m.
To the south over the Guianas, analysis indicated a low level trough traversing the area. Consequently, partly cloudy to cloudy skies with some scattered moderate showers, light rain and isolated thunderstorms were reported across the region.
A trough along the diffluent side of the deep layered low pressure system centered near 32N 84W was responsible for the cloudy skies, scattered showers, rain and thunderstorm activity experienced over southern Bahamas, Hispaniola and to a lesser extent Puerto Rico today. Most of the activity however, remained north of the area over open water. On the other hand, the subsident side of this feature maintained a relatively stable atmosphere over Cuba and Jamaica for most of the day. Nevetheless, adequate moisture and instability allowed for some localized convection to develop over some sections of these islands by mid to late afternoon.
Eastern Caribbean Outlook
The surface to low level shearline will maintain some measure of instability over the Leewards and extreme northern Windward islands over the next four days. Furthermore, the surface to mid level trough currently affecting the Central Caribbean, will continue to drift in a eastward direction while merging with the shearline currently affecting the area. Although these features will merge, model data is suggesting that most of the moisture over those islands, will largely remain confined to the lower levels. In addition to this, these moisture levels are also expected to fluctuate, hence shower activity will be mostly fragmented.
Meanwhile, weak instability associated with the above mentioned surface to low level shearline, is predicted to interrupt the dominance of the surface to low level Atlantic high pressure system. Subsequently, Barbados and some of the Windward islands are likely to experience occasional cloudiness with a few scattered showers tomorrow into Wednesday. Thereafter, the surface to low level Atlantic high pressure system will once again regain dominance over the area.
Western Caribbean Outlook
A subsident pattern is predicted to reside across the Western Caribbean over the next couple days and as a result, fair conditions will mostly prevail. Nevertheless, some mid to late afternoon localized activity will still be likely over some sections of the Bahamas, Cuba and Jamaica. On the other hand, surface to mid level instability associated with the trough along the diffluent side of the low pressure system, will maintain cloudiness, shower activity and a few isolated convective cells over Hispaniola and Puerto Rico tonight. However, late tonight into tomorrow, Hispaniola will begin to experience improved weather conditions, as the feature continues to drift eastward while conditions persist over Puerto Rico. Despite this, the bulk of the activity is still anticipated to remain further north of these islands over open water.
|Meteorologist Wayne McGeary|