886
FXCA20 KWBC 301244
PMDCA
TROPICAL DISCUSSION - INTERNATIONAL DESKS
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
843 AM EDT THU MAR 30 2023
PRELIMINARY DISCUSSION FOR PUERTO RICO AND THE USVI FROM MAR
30/12UTC: PATCHES OF MOISTURE WILL MOVE IN TODAY...CAUSING
PRECIPITABLE WATER TO GO UP DURING THE DAY...BUT DOWN AGAIN IN THE
EVENING. MOISTURE WILL INCREASE VERY BRIEFLY ON FRIDAY MORNING BUT
WILL DECREASE AGAIN IN THE AFTERNOON AND INTO THE WEEKEND...THEN A
BRIEF INCREASE IN MOISTURE COULD BE OBSERVED ONCE AGAIN ON SUNDAY.
SCATTERED SHOWERS HAVE BEEN AFFECTING EASTERN PR IN THE MORNING
AND THESE SHOWERS WILL CONTINUE INTO THE MID MORNING HOURS. THIS
AFTERNOON...SHOWERS ARE FORECAST TO DEVELOP ACROSS WESTERN
INTERIOR TO NORTHWESTERN SECTIONS OF PR AS THE AVAILABLE MOISTURE
COMBINES WITH THE DIURNAL HEATING AND SEA BREEZE CONVERGENCE. THE
TOTAL RAINFALL AMOUNTS ARE EXPECTED TO BE BETWEEN A QUARTER OF AN
INCH TO A HALF AN INCH ACROSS AREAS OF EASTERN PR DUE TO THE
MORNING SHOWERS...THEN OVER A HALF AN INCH OF RAIN IS POSSIBLE
ACROSS THE WESTERN INTERIOR OF PR THIS AFTERNOON.
BY FRIDAY ONWARD...THE AVAILABLE MOISTURE WILL DECREASE...AND THE
SHOWER ACTIVITY AND FORECAST WILL BE LESS ON FRIDAY AND SATURDAY.
HOWEVER...THERE WILL BE A NARROW BAND OF MOISTURE IN THE AREA JUST
AHEAD OF A COLD FRONT. THE DIFFERENT MODEL GUIDANCE IS STILL
DIFFERING IN TIMING AND LOCATION....THE GFS MODEL HAS MUCH LESS
RAINFALL OVER THE AREA LATE FRIDAY INTO SATURDAY COMPARED OT THE
ECMWF. THE CURRENT FORECAST SPLIT THE DIFFERENCE AND SHOWS SOME
RAIN ON FRIDAY INTO SATURDAY BUT GENERALLY LESS THAN A TENTH OF AN
INCH. THERE IS A POSSIBILITY OF A PREFRONTAL TROUGH OVER THE AREA
LATE THIS WEEKEND...WHICH WILL CAUSE GOOD CLOUD COVER AND POSSIBLY
PERSISTENT SHOWER ACTIVITY ACROSS THE NORTHEASTERN CARIBBEAN. THAT
SAID...ONCE AGAIN THE GFS HAS LESS RAINFALL THAN THE ECMWF...SINCE
THE EUROPEAN MODEL FAVORS LESS CLOUDINESS AND SUGGESTS SOME
AFTERNOON CONVECTION ACROSS SOUTHWESTERN PR. THE BANDS OF MOISTURE
AND DRY AIR ARE VERY NARROW AND THEREFORE THE IS SOME UNCERTAINTY
ON PRECISE LOCATION.
AT THE SURFACE THERE IS LOW PRESSURE THAT IS MOVING EAST ACROSS
THE WESTERN ATLANTIC TODAY...RELAXING THE LOCAL PRESSURE GRADIENT.
ANOTHER SURFACE HIGH PRESSURE WILL START TO MOVE INTO THE THE
WESTERN ATLANTIC BY EARLY FRIDAY MORNING...WHICH WILL CONTINUE
MOVING EAST AND SHOULD BE IN THE CENTRAL ATLANTIC BY SUNDAY.
ACROSS THE MID LEVELS THERE IS WEAK TROUGHINESS THAT COULD
APPROACH THE AREA ON FRIDAY. FOR SATURDAY...A STRONGER HIGH
PRESSURE ACROSS THE EASTERN GULF OF MEXICO INTO THE WESTERN
CARIBBEAN WILL DOMINATE THE AREA FOR THE WEEKEND AND EARLY NEXT
WEEK. THERE IS NO STRONG TRADE WIND CAP EXPECTED TODAY INTO
FRIDAY...BUT THE TRADE WIND INVERSION WILL RETURN LATE FRIDAY
INTO THE WEEKEND. ACROSS THE UPPER LEVELS...AN UPPER TROUGH OVER
THE WESTERN CARIBBEAN IS FORECAST TO DEVELOP LATE TONIGHT INTO
FRIDAY. THE UPPER TROUGH WILL BE MOVING IN FROM THE WEST WITH ITS
AXIS MOVING THROUGH PR/USVI FRIDAY INTO SATURDAY.
AT THIS TIME...FRIDAY LOOKS TO BE THE DAY WITH THE LEAST AMOUNT OF
RAINFALL ACCUMULATION. EVERY OTHER DAY IS FORECAST TO HAVE TRADE
WIND SHOWERS AFFECTING EASTERN PR AND THE USVI...ESPECIALLY
OVERNIGHT AND IN THE EARLY MORNING...THEN AFTERNOON SHOWERS ACROSS
PORTIONS OF WESTERN PR.
ALAMO...WPC (USA)
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