Dry air at mid to upper levels across our area (SVG), resulted in fair conditions. This dry air intrusion is caught in the cyclonic circulation of Subtropical Storm Oscar which was named last night. ’Oscar’ is pushing westward and could induce couple lower level troughs to drift southward across the island chain from early Sunday resulting in weak instability with few scattered showers.
On Monday, as Oscar should be moving northward and away from the Lesser Antilles, moisture at the mid levels should be increasing with a lower level trough (previously tropical wave) approaching by afternoon with shower activity overnight into Tuesday. Models indicate that lower level moisture could be converging across the islands until the end of the week (Friday), as an Atlantic High Pressure System maintains moisture feed to Oscar.
Gentle (10 - 20km/h) north-easterly breeze should increase to moderate (up to 30 km/h) overnight, decreasing again by Sunday afternoon with a slight veering to east south-east and becoming light to gentle (5-20 km/h) by afternoon. Overnight Monday a backing east north-easterly moderate breeze should veer to east south-east by Tuesday afternoon with the crossing of the lower level trough/tropical wave.
Mean sea level (MSL) readings across our area should range 1012 – 1014 mb, by Sunday afternoon/evening ‘Oscar’ could cause a temporary dip in MSL readings to 1010 – 1012mb.
Good visibility is expected along with smooth to slight across SVG. Smooth seas may be experienced on west coasts, with a gradual rise in wave heights expected by late Monday to peak near 1.2m on west coasts and 1.8m on east coasts in north north-easterly swells. Slight dust concentrations may reduce visibility on our horizon late Tuesday.
Notes:
- At 5:00 pm, the center of Subtropical Storm Oscar was near latitude 26.9 North, longitude 50.7 West. The storm is moving toward the west near 17 mph (28 km/h). A turn toward the west-southwest is anticipated overnight (to be termed A TROPICAL STORM), followed by a turn back towards the west on Sunday. Oscar is forecast to begin moving toward the north and then the northeast early next week.
- Tropical wave along 49W from 03N-14N, moving west at 10-15 kt. Scattered showers are noted along the northern portion of the wave mainly north of 10N. TPW satellite imagery shows this wave embedded in a region of deep layer moisture…. about 720 nmiles away… vicinity Monday.