812
FXCA20 KWBC 241239
PMDCA
TROPICAL DISCUSSION - INTERNATIONAL DESKS
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
838 AM EDT MON JUL 24 2023
PRELIMINARY DISCUSSION FOR PUERTO RICO AND THE USVI FROM JUL
24/12UTC: SMALL AMOUNTS OF SAHARAN DUST WILL PREVAIL OVER PR/USVI
TODAY AND EARLY TUESDAY. A TROPICAL WAVE AND AN ASSOCIATED LOW
PRESSURE WILL MOVE INTO THE CARIBBEAN...PASSING MOSTLY TO THE
SOUTH OF THE LOCAL ISLANDS ON TUESDAY INTO WEDNESDAY.
HOWEVER...THE AVAILABLE MOISTURE WILL INCREASE ON TUESDAY WITH THE
APPROACHING TROPICAL WAVE. THE PRECIPITABLE WATER VALUES...OVER
THE NEXT 5 DAYS ARE FORECAST TO RANGE BETWEEN 1.6 AND 2.1
INCHES...BOTTOMING OUT THIS AFTERNOON AND THE PEAK MOISTURE
EXPECTED ON TUESDAY AFTERNOON. A STRONG SFC HIGH PRESSURE WILL
CAUSE EASTERLY WINDS THROUGH THE WEEK. IN THE MID-LEVELS...A WEAK
RIDGE WILL PREVAIL OVER THE LOCAL AREA...BUT NO STRONG TRADE WIND
INVERSION IS FORECAST...WITH THE EXCEPTION OF BRIEF MOMENTS IN THE
OVERNIGHT HOURS.
IN GENERAL...LOCALLY INDUCED CONVECTION IS EXPECTED EACH AFTERNOON
FOR THE NEXT SEVERAL DAYS...WITH TRADE WINDS SHOWERS AFFECTING
PR/USVI IN THE NIGHTTIME AND EARLY MORNING HOURS. HOWEVER...THE
APPROACHING TROPICAL WAVE ON TUESDAY WILL CAUSE THE SHOWER AND
THUNDERSTORM ACTIVITY TO INCREASE. THE EGDI ALGORITHM SUGGESTS THE
POSSIBILITY OF ISOLATED TO SCATTERED THUNDERSTORMS ON
TUESDAY...THEN A STRONGER SIGNAL IS OBSERVED EARLY
WEDNESDAY...ASSOCIATED WITH THE EAST SIDE OF THE WAVE
AXIS...SUGGESTING SCATTERED THUNDERSTORMS BUT MAINLY OVER THE
CARIBBEAN WATERS...VERY CLOSE BUT JUST SOUTH OF THE LOCAL ISLANDS.
THURSDAY AND FRIDAY WOULD RETURN TO THE TRADE WIND SHOWER AND
AFTERNOON CONVECTION ACROSS WESTERN PR PATTERN.
FOR TODAY...BRIEF TRADE WIND SHOWERS ARE FORECAST FOR EASTERN PR
AND USVI...WITH RAINFALL TOTAL MAX BETWEEN A QUARTER AND 0.4
INCHES...WHILE AFTERNOON CONVECTION WILL AFFECT WESTERN
PR...CAUSING RAINFALL TOTALS OF NEARLY AN INCH IN SOME AREAS. THAT
SAID...OUT OF THE NEXT 5 DAYS...TUESDAY AND WEDNESDAY ARE EXPECTED
TO BE THE OVERALL RAINIEST DAYS...BUT WITH A SLIGHT NUDGE TO
TUESDAY DUE TO MOISTURE ADVECTION AT THE TIME OF MAX HEATING. THIS
IS WHY OVER 1 INCH OF RAIN IS FORECAST ACROSS EASTERN PR AND
NEARLY 1.5 INCHES ACROSS WESTERN PR...WHILE THE USVI WILL HAVE
ABOUT A QUARTER OF AN INCH OR LESS. EVEN THOUGH THERE IS SOME
LINGERING MOISTURE EARLY ON WEDNESDAY...THERE WILL BE A DRYING
TREND...SO THE AMOUNTS OF RAIN FORECAST ON WEDNESDAY ARE UNDER A
HALF AN INCH ACROSS EASTERN PR...AND AROUND 1.3 INCHES FOR
PORTIONS OF WESTERN PR...WHILE THE USVI WOULD HAVE AROUND A TENTH
OF AN INCH. THEN FOR THURSDAY AND FRIDAY...MORE MODEST AMOUNTS OF
RAIN ARE FORECAST THOUGH WITH THE TYPICAL PATTERN. THE 5-DAY
RAINFALL TOTAL IS FORECAST TO BE JUST OVER 2 INCHES ACROSS EASTERN
PR...OVER 3 INCHES OVER PORTIONS OF WESTERN PR...AND NEAR 0.4 -
0.8 INCHES ACROSS THE USVI.
ALAMO/GALVEZ...WPC (USA)
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