213
FXCA20 KWBC 221143
PMDCA
TROPICAL DISCUSSION - INTERNATIONAL DESKS
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
742 AM EDT FRI MAR 22 2024
PRELIMINARY DISCUSSION FOR PUERTO RICO AND THE USVI MAR 22/12UTC:
A COLD FRONT HAS STALLED ALONG 23.6W 60W...EASTERN HISPANIOLA
WHILE A SHEAR LINE HAS DEVELOPED AND EXTENDS ALONG 22N
60W...NORTHEAST PUERTO RICO. CONVECTION WITH THESE SYSTEMS IS
ISOLATED IN COVERAGE...WHICH IS SUGGESTED BY SATELLITE IMAGERY AND
CONFIRMED BY THE SAN JUAN RADAR. THE TRADES ARE BECOMING ALMOST
DUE EAST...WITH AN AVERAGE WIND DIRECTION OF 80 DEGREES OVER THE
ISLANDS. ALTHOUGH FAIR WEATHER IS PRESENT...PRECIPITABLE WATER
CONTINUES TO REMAIN ABOVE THE NORMALS FOR LATE MARCH AS IT IS IN
THE 37-42MM RANGE. THE COMBINATION OF AN UNSEASONABLY MOIST
ENVIRONMENT AND THE CURRENT TRADE WIND DIRECTION WILL ALLOW FOR
THE DEVELOPMENT OF AFTERNOON CONVECTION IN THE WESTERN CORDILLERA.
EXPECT MAXIMA IN THE 0.5-0.75 IN RANGE. A DRYING TREND FOLLOWS
GIVEN THE INTENSIFICATION OF THE MID-LEVEL RIDGE. THIS WILL FAVOR
VERY LIMITED PRECIPITATION ON SATURDAY.
THE SYSTEM OF INTEREST IS THE CURRENT UPPER TROUGH MOVING ALONG
THE EASTERN USA INTO THE NORTH ATLANTIC. THIS TROUGH IS FORECAST
TO APPROACH THE FORECAST AREA ON MONDAY...TO FAVOR A SHORT-LIVED
PEAK IN PRECIPITATION AS IT ARRIVES IN TUNE WITH THE ASSOCIATED
SURFACE FRONT. GIVEN A LOWERING OF THE SURFACE PRESSURES TO THE
NORTH OF THE ISLANDS...EXPECT THE TRADES TO VEER AND BECOME
SOUTHERLIES AS EARLY AS SUNDAY AFTERNOON PERSISTING OVERNIGHT INTO
EARLY MONDAY. THIS WILL FAVOR LIGHT RAIN SHOWERS ALONG SOUTHERN
AND SOUTHEAST PUERTO RICO OVERNIGHT. THE FRONT IS EXPECTED TO
ARRIVE ON MONDAY MORNING ACCOMPANIED BY A CHANGE OF WIND DIRECTION
TO SOUTHWESTERLY. THIS WILL FAVOR THE LARGEST ACCUMULATIONS TO
CLUSTER ALONG CENTRAL AND NORTHERN PUERTO RICO...WHERE EXPECT
AMOUNTS OF 0.5-0.75 INCHES. WESTERN...EASTERN PUERTO RICO AND THE
NORTHERN VI ARE LIKELY TO RECEIVE MAXIMA OF 0.25 TO 0.5
INCHES...WHILE ST. CROIX AND SOUTH-CENTRAL PUERTO RICO SHOULD
EXPECT LESSER AMOUNTS. SURFACE WINDS ARE FORECAST TO RAPIDLY
CHANGE TO NORTHWESTERLIES DURING MONDAY EVENING...ADVECTING A
COOLER AND ESPECIALLY DRIER AIR MASS FROM THE NORTH. ALTHOUGH
PRECIPITABLE WATER IS EXPECTED TO SHARPLY DECREASE ONLY BY TUESDAY
EVENING...THE CONVERGENT TIER OF THE UPPER TROUGH WILL LIMIT
POTENTIAL ACCUMULATION ON TUESDAY TO MAXIMA UNDER 0.4 INCHES IN
SOUTH-CENTRAL AND SOUTHEAST PUERTO RICO...AS WELL AS ST. CROIX. IN
AREAS TO THE NORTH AND WEST...EXPECT AMOUNTS GENERALLY UNDER THE
0.2 ON MARK FROM TUESDAY MORNING THROUGH WEDNESDAY MORNING.
GALVEZ/ACOSTA...WPC (USA)
CLICK HERE TO GO TO PREVIOUS BULLETINS.
Main Text Page