13:08 UTC MAY 18 2021

DISCUSSION:   LOW MOISTURE LEVELS ACROSS THE NORTHEAST CARIBBEAN CONTINUE TO RESTRICT SHOWER ACTIVITY WITH MOSTLY SUNNY SKIES PREVAILING ACROSS THE ISLANDS. THE CHANCES OF SHOWERS ARE STILL SLIGHT OR JUST ABOUT 20 PERCENT FOR THE MOST. THERE HAS ALSO BEEN A WEAKENING OF THE PRESSURE GRADIENT ACROSS THE REGION AS A TROUGH SYSTEM ADVANCING FROM THE WEST STARTED TO AFFECT THE WIND REGIME. WIND SPEEDS FOR THE PREVIOUS SEVERAL HOURS HAVE BEEN AS LOW AS 7 KM/H OR 5 MPH. THE FORECAST MODELS OVER THE NEXT 24 HOURS ARE ALL CONSISTENT IN MAINTAINING A SLACK PRESSURE GRADIENT; THEREFORE, A LIGHT TO GENTLE AND EAST-SOUTHEASTERLY WINDFLOW IS ANTICIPATED THROUGHOUT THE FORECAST PERIOD. THE NIGHT-TIME WIND DIRECTION IS ANTICIPATED TO BE VARIABLE AT TIMES. THE MODELS ARE ALSO PERSISTING WITH ANOTHER 24 HOURS WHERE A DRY ATMOSPHERE WILL CONTINUE TO RESTRICT SHOWER ACTIVITY OVER THE LEEWARDS. HOWEVER, STARTING WEDNESDAY AFTERNOON, SOME DEEPER MOISTURE AND INSTABILITY BEING BROUGHT INTO THE REGION FROM THE ADVANCING TROUGH WILL INCREASE THE CHANCES OF SHOWERS OVER THE BRITISH VIRGIN ISLANDS. THE CHANCES OF SHOWERS WILL INCREASE TO 60 PERCENT OR MODERATE.

FORECASTER

LORNE SALMON