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FXCA20 KWBC 141232
PMDCA
TROPICAL DISCUSSION - INTERNATIONAL DESKS
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
832 AM EDT FRI APR 14 2023
PRELIMINARY DISCUSSION FOR PUERTO RICO AND THE USVI FROM APR
14/12UTC: THE LATEST MODEL GUIDANCE STILL SUGGESTS THAT LOCALLY
INDUCED CONVECTION WILL BE THE MAIN REASON FOR RAINFALL
DEVELOPMENT ACROSS WESTERN PUERTO RICO...THOUGH BRIEF SHOWERS ARE
EXPECTED ACROSS EASTERN PUERTO RICO. THE USVI WILL ALSO BE LIMITED
TO OBSERVING BRIEF SHOWERS OVER THE NEXT FEW DAYS...AND THE
ACCUMULATIONS ARE NOT EXPECTED TO BE MUCH MORE THAN A FEW
HUNDREDTHS EACH DAY. THE 5-DAY RAINFALL TOTAL IS FORECAST TO BE
OVER 3 INCHES ACROSS THE WESTERN INTERIOR SECTIONS OF PUERTO
RICO...WHILE EASTERN AND NORTHEASTERN PUERTO RICO IS FORECAST TO
HAVE AROUND ONE INCH. THE 5-DAY RAINFALL FORECAST FOR THE USVI IS
AROUND A QUARTER OF AN INCH...BUT ISOLATED AREAS COULD RECEIVE
HIGHER AMOUNTS.
THE OVERALL MOISTURE WILL BE NEAR NORMAL OVER THE NEXT SEVERAL
DAYS...THOUGH IT WILL INCREASE GRADUALLY ON SATURDAY...WITH
PRECIPITABLE WATER PEAKING AT AROUND 1.7 INCHES BY SATURDAY
AFTERNOON/EVENING...THEN GRADUALLY DECREASING TO AROUND 1.3 INCHES
BY SUNDAY EVENING. THERE IS ALSO A MID-LEVEL RIDGE OVER THE LOCAL
AREA THAT WILL REMAIN OVER THE NORTHEAST CARIBBEAN THROUGH THE
MIDDLE OF NEXT WEEK. A WEAK TRADE WIND CAP NEAR 850-750 HPA IS
EXPECTED TODAY...BUT NO SIGNIFICANT CAP IS SUGGESTED BY GUIDANCE
THROUGH THE WEEKEND. ON MONDAY ONWARD...A WEAK CAP AT ABOUT 750HPA
IS POSSIBLE. THERE IS ALSO A WEAK UPPER LEVEL RIDGE OVER THE LOCAL
AREA TODAY...THOUGH A WEAK UPPER TROUGH COULD BE OBSERVED OVER THE
WESTERN CARIBBEAN THIS WEEKEND...FLATTENING AS IT APPROACHES THE
LOCAL ISLANDS. THE LACK OF STRONG DYNAMICS IS THE REASON WHY
LOCALLY INDUCED CONVECTION IS EXPECTED TO BE THE MAIN REASON FOR
SIGNIFICANT RAINFALL OVER THE NEXT FEW DAYS. THIS IS THE
COMBINATION OF THE NEAR NORMAL AVAILABLE MOISTURE...WITH THE SEA
BREEZE CONVERGENCE AND DIURNAL HEATING. A WEAK SURFACE FRONT IS
FORECAST TO REACH 20N TODAY...WHILE IT GRADUALLY CONTINUES TO
WEAKEN THROUGH THE WEEKEND. ALTHOUGH THE FRONT IS NOT FORECAST TO
REACH PUERTO RICO...THE EASTERLY WIND FLOW THROUGH SATURDAY WILL
ENHANCE SHALLOW CONVECTIVE INSTABILITY OVER THE LOCAL
AREA...SLIGHTLY ENHANCING LATE EVENING/EARLY MORNING TRADE WIND
SHOWERS ACROSS EASTERN PUERTO RICO. THE TRADE WIND SHOWERS WILL
DECREASE ON SUNDAY ONWARD...WHEN THE FRONT IS EXPECTED TO BE
FRAGMENTED.
IN TERMS OF EXPECTED TOTALS...UNDER THE INFLUENCE OF EASTERLY WIND
FLOW...THE HIGHEST ACCUMULATIONS ARE EXPECTED ACROSS WESTERN
PUERTO RICO EACH AFTERNOON. FROM TODAY INTO THE WEEKEND...EXPECT
MAXIMA OF AROUND 0.75 TO 1.5 INCHES. EARLY IN THE UPCOMING
WORKWEEK...THE MAXIMA IS FORECAST TO BE NEAR 0.5 INCHES. FOR THE
USVI...IN GENERAL...AROUND A TENTH OF AN INCH OR LESS ARE FORECAST
EACH DAY.
ALAMO/ACOSTA...WPC (USA)
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