The tail-end of a tropical wave (with pockets of dry air) is affecting the island chain. Overnight, a possible shift in the tilt of an upper level trough could support some scattered showers. However, a Layer of dry Saharan Dust and Air should create dry/stable and hazy conditions from Friday into the weekend. By Friday night, dust concentrations are expected to reduce visibility and air quality significantly,
with PM2.5 levels expected to reach near 20 µg/m3 and PM10 levels near 30µg/m3. Isolated showers are possible, with most shower activity remaining just east of the island chain during Saturday, as the Atlantic High Pressure System rebuilds.
The Atlantic High Pressure System should steer an easterly wave (analyzed near 32W south of 10N this morning at 8:00am/12z) towards the region by Monday. Although hazy conditions may persist, models suggest that this instability from moist equatorial regions could result in rainfall accumulations near 35 - 40 mm, with thunderstorm activity possible by Monday afternoon. Few short wave troughs at upper levels could create such diffluent supportive pattern across the Windward Islands.
Moderate to fresh (20 - 40 km/h) breeze is expected over the next few days, becoming gentle by Monday afternoon with the easterly wave.
Mean sea-level pressure should range 1012 mb - 1016 mb, gradually rising by Saturday night to range 1016-1018 mb during Monday as the High Pressure builds.
Moderate easterly sea swells can be expected to peak near 1.5 m on west coasts and near 2.2 m on east coasts, temporarily decreasing late Sunday (1.0 m to 1.8 m) with swells propagating from the east north-east, on east coasts and continuing Monday.