As the instability lingers across our islands tonight, expect periods of light rain with occasional scattered showers. A temporary drying of the lower atmosphere is expected overnight into Saturday with few isolated showers.
A low which moved off the USA east coast with an associated frontal boundary should move across the Atlantic north of the island chain. Meanwhile, an Atlantic High Pressure should build in the Central Atlantic Ocean east of the island chain. These two features could squeeze an area of instability (moisture/showers) across our islands. As moisture converges on the southwestern edge of the High Pressure, instability/moisture levels could start increasing across our islands late Saturday into Sunday. Rainfall accumulations of 1 and ½ to 2 inches (35-50mm) are possible overnight Sunday. Troughing/shearline features across our islands could create very unstable conditions on Monday, with some models suggesting that 2 to 3 inches (50-75mm) are possible on Monday.
Light and variable winds should only increase to weak moderate (up to 25km/h) breeze from the east south-east overnight and Saturday. The flow around the Atlantic High Pressure should steer southerly light to gentle breeze on Sunday. By evening, winds from the two features should meet us with calm to light (<12km/h) air from south south-west changing to northerly on Monday due to the frontal boundary. A fall in Mean sea-level pressure should start on Saturday reaching 1008-1010mb during Sunday, values should rise on Monday.
Visibility should remain good, with less than 20 ug/m**3 in dust concentration across our area. Slight to moderate seas in open water with swells up to 1.5m on west and up to 2.0m on east should remain slight on the west for Saturday and Sunday. Some deterioration in sea conditions due to large swells propagating southwards from the deep-layered low pressure system in the northern Atlantic could result increased northerly swells on Monday. A HIGH-SURF ADVISORY and SMALL CRAFT WARNING may become necessary from 6pm Sunday 4th March.