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: 20190422 PERIOD: Evening
The Atlantic high pressure system was the dominant feature across Barbados, the central and southern Windwards and the northern Leeward islands. A reduction in low level moisture due to a drier low level environment over these areas, generated mainly fair skies with little to no reported shower activity. Over the southern Leewards and northern Windwards however, a surface to low level shearline horizontally positioned across the area, generated some scattered showers under partly cloudy to cloudy skies.
Trinidad and Tobago experienced occasional cloudy skies with a few showers as another weak surface to low level shearline affected the twin island.
Over the Guianas, partly cloudy to cloudy skies, brief showers and light rain were reported mainly over French Guiana. A weak surface to low level trough was present over that area, lending to the precipitation which was observed
Winds across the region whilst occasionally below 10 knots across some islands, reached as high as 19 knots mainly over the central Windwards. Seas remain moderate in open water with swells peaking to 2.0m.
Over the western Caribbean, a surface to low level high pressure system centered over the south east U.S, was the dominant feature. Some showers were present in the vicinity of the Cayman Islands and parts of Cuba. A weak surface to low level trough extending southward over Hispaniola, generated cloudy skies with a few showers. A weak surface to low level shearline was responsible for generating the brief showers across Puerto Rico and the Virgin islands.
Tonight: The surface to low level shearline will gradually weaken across the northern Windward islands however some brief showers will remain likely. An improvement in conditions is expected across the southern Leeward islands during this time. Here in Barbados and the central Windwards, fair to partly cloudy skies will remain with some brief showers expected. Meanwhile over the southern Windward islands, another surface to low level shearline is likely to generate some brief showers under occasionally cloudy skies. A deep layered low pressure system centered near 26N52W, will continue to slacken the pressure gradient as the system moves westward over the central Atlantic. Thus winds are expected to decrease across the eastern Caribbean to near 10 to 15 knots over the next few days.
Tuesday: The weak surface to low level shearline will gradually weaken across the northern Windwards, however weak troughing will remain across the northern portions of the region where some brief isolated showers are likely. A building low level equatorial high pressure system will advect moisture across Barbados and the southern Windward islands, thus some showers are likely. The central Windward islands can expect fair conditions during this time. By nightfall, moisture and instability associated with the shearline feature previously over the southern Windwards, will spread across Barbados and much of the Windward islands. In addition to this, a moist and unstable south westerly mid to upper level wind flow will combine to generate cloudy skies, showers and rain across the just mentioned areas.
Wednesday: Analysis indicates some drying of the lower levels across Barbados and the southern Windward islands as the surface to low level shearline weakens. Nevertheless, mid to upper level conditions will remain relatively favourable allowing for occasional rain to develop across the area. Some isolated areas of enhanced convection is likely over some islands. The Leeward islands will remain under fair to partly cloudy conditions during this time, with some brief isolated showers being generated from a weak surface to low level trough over that area.
Thursday: A surface trough is expected to develop over the Windward islands. Low level moisture on the south western periphery of the equatorial high will be advected over Barbados and the Windward islands. This in combination with the surface trough with generate some showers across the area. At the mid to upper levels, south westerly wind flow pulling moisture from over the south American continent, will provide favourable enhancement to showers, rain and possible thunderstorm activity across some islands. In contrast, fair skies are forecast across the Leeward islands.
Friday: Instability will gradually spread across the southern Leeward islands. A gradual improvement in conditions expected across Barbados and the extreme southern Windwards as the activity is pushed northward under the influence of the building low level equatorial high. The northern Leewards will remain under fair conditions during this time.
Tonight: A building surface to low level high pressure system centered over the south eastern U.S, will be dominant across the western most Bahamian islands, western Cuba and the Yucatan Peninsula. A weak surface to low level trough extending southward over Hispaniola will continue to generate a few showers. Meanwhile weak surface to low level ridging will be dominant across Puerto Rico and the Virgin islands.
Tuesday: No significant change in conditions is expected across the basin. However over the south eastern Caribbean sea. Unstable conditions are expected to develop as a surface to low level shearline affects the area. Moist, unstable mid to upper level south westerly wind flow pulling moisture from over the south American continent will add to the instability, thus convective activity is possible.
Wednesday: Some weak low level troughing will generate a few showers across the Greater Antilles. Meanwhile the weak surface to low level western Atlantic high pressure system remains dominant across the basin. Conditions will remain unchanged across the south eastern Caribbean Sea.
Thursday: Shower activity will gradually spread across the southern Caribbean Sea over the ABC islands. Elsewhere, no significant change in conditions from the previous day is expected.
Friday: Surface to low level instability will be present across much of the eastern Caribbean Sea south of Hispaniola and Puerto Rico. Besides, the arrival of a frontal system over the Yucatan Peninsula, no significant change in conditions is expected elsewhere across the basin.