Barbados Meteorological Services
Charnocks ChCh
Weather Discussion

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: 20170727 PERIOD: Evening

David Harding 4 Evening ...TROPICAL WAVES...

An eastern Atlantic tropical wave extends along 31W from 04N to
17, moving west at 10 kt. Scattered moderate convection is noted
from 07N to 12N between 30W and 35W.

A central Atlantic tropical wave extends along 42W from 03N to
16N moving west at 10 to 15 kt. No significant convection is
associated with this tropical wave.

A tropical wave is along 59W/60W from 12N to 23N moving toward the
Lesser Antilles at 15 to 20 kt. The tropical wave is interacting
with an upper low centered near 26N58W, and is much better
represented north of 18N as a result.
Partly cloudy to cloudy skies were observed over Barbados and the southern Windward isl;ands from as early as daybreak as a weak tropical wave passed over the area. A few scattered showers and some convective cells were generated as a result of this wave, Miosture were relatively low and confined to the lower levels of the atmosphere. However, by mid afternoon a gradual improvement in weather conditions was noticeable as the wave drifted westward across the western Atlantic.
Over the northern Windward and Leeward islands fair to partly cloudy skies were experienced as a weak ridge pattern lingered over the region.
Further south, moderate convective activity was experienced across mainly Guyana while the remainder of the Guianas remained under partly cloudy skies with occasional scattered light showers due to the presence ot the I.T.C.Z.
Winds across the region ranged between 8 to 16 knots during the day. Seas remained slight to moderate in open water with swells peaking to 2.0m. TROPICAL WAVES..........

A Caribbean tropical wave at 73W south of 17N, extends between Haiti and northeast
Colombia moving west at 15 to 20 kt. The tropical wave is moving
toward an upper low centered over central Cuba, and will start
interacting with the upper low through tonight, complicating
precise position analysis
A few scattered showers and isolated thunderstorms were experienced over Cuba during the day as a weakening upper level low over the area generated these conditions. While a tropical wave just south of the coast of Haiti in conjunction with daytime heating also produced a few scattered showers and a few isolated thunderstorms over the area. Further east and over the Bahamas a more dry and stable atmosphere was observed.
Over central America (Costa Rica, Panama, Nicagura and parts of Honduras) high moisture levels, coupled with a surface trough also produced scattered showers and thunderstorm activity over the area. As the tropical wave with axis presently near 61W continues to drift westward across the Caribbean sea, some improvement in weather conditions will be anticipated here in Barbados and across the eastern Caribbean as the high pressure system will re-establish itself across the island chain from tonight. Model data is indicating a more stable atmosphere as a reduction in low to mid level moisture is also noticeable. A weak shearline is anticipated to approach the southern Windwards Friday night into Saturday morning, however model data is suggesting low moisture levels and as a result no significant rainfall is expected. A layer of Saharan dust is expected to drift over the region around Saturday and as a result hazy conditions and a reduction in horizontal visibility can be expected.
By late Monday a tropical wave presently near 31W will approach area and some scattered showers will be expected as an increase in moisture is noticeable. Tropical wave presently near 61W which is moving across the western Caribbean will maintain some weak instability across the Venezuela coastlines over the next 24 to 36 hours. As a result, some scattered showers can be expected. While the tropical wave near 73W will produce some scattered showers and possible isolated thunderstorms over parts of south and central America over the next few days.