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FXCA20 KWBC 101244
PMDCA
TROPICAL DISCUSSION - INTERNATIONAL DESKS
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
844 AM EDT MON JUL 10 2023
PRELIMINARY DISCUSSION FOR PUERTO RICO AND THE USVI FROM JUL
10/12UTC: A DRYING TREND IS EXPECTED TODAY AS SAHARAN DUST MOVES
THROUGH PR/USVI TODAY...LINGERING INTO TUESDAY...WHICH WILL LIMIT
THE COVERAGE AND AMOUNT OF RAIN. A TROPICAL WAVE IS FORECAST TO
MOVE THROUGH THE LOCAL AREA ON WEDNESDAY...WHICH WILL INCREASE THE
AVAILABLE MOISTURE SIGNIFICANTLY. PRECIPITABLE WATER IS FORECAST
TO BE NEAR TWO STANDARD DEVIATIONS HIGHER THAN NORMAL BY WEDNESDAY
EVENING. SIGNIFICANT SHOWER ACTIVITY IS EXPECTED ON WEDNESDAY AND
WEDNESDAY NIGHT...THE HIGHEST AMOUNTS OF RAIN BEING EXPECTED
ACROSS EASTERN PR. SAHARAN DUST WILL RETURN EARLY ON
THURSDAY...CAUSING ANOTHER DRYING TREND FOR THE LATTER PART OF THE
WORKWEEK. THERE WILL ALSO BE TRADE WIND INVERSIONS AT AROUND 850
HPA TODAY INTO TUESDAY...THEN THURSDAY INTO FRIDAY.
AN ELONGATED SFC HIGH PRESSURE EXTENDING ACROSS THE TROPICAL
ATLANTIC IS EXPECTED TO GENERALLY KEEP E-ESE WINDS THIS WEEK. IT
WILL BE SOMEWHAT BREEZY ACROSS THE CARIBBEAN BASIN THIS WEEK.
WINDS COULD BE AS STRONG AS 25 KNOTS ACROSS THE CARIBBEAN.
HOWEVER...FOR PR/USVI THE BREEZIEST DAY IS FORECAST TO BE
WEDNESDAY JUST AHEAD OF THE TROPICAL WAVE...WITH WINDS AROUND
20-22 KNOTS ACROSS THE LOCAL WATERS AND COASTAL AREAS. IN THE MID
LEVELS...A WEAK HIGH PRESSURE IS EXPECTED TO MEANDER ACROSS THE
TROPICAL ATLANTIC THIS WEEK. IN THE UPPER LEVELS...A NARROW TROUGH
EAST OF PR WILL SLOWLY WEAKEN TODAY AND TUESDAY...BUT A LOW
PRESSURE WILL DEVELOP SOUTH OF PR BY WEDNESDAY...THEN WILL MOVE
WEST ACROSS THE CARIBBEAN SEA. SOUTHERLY WINDS IN THE UPPER LEVELS
ARE EXPECTED ACROSS THE LOCAL ISLANDS ON WEDNESDAY INTO
THURSDAY...COINCIDING WITH THE APPROACHING TROPICAL WAVE.
THE AVAILABLE MOISTURE WILL BE NEAR NORMAL TODAY THROUGH EARLY
WEDNESDAY...WITH PRECIPITABLE WATER RANGING BETWEEN 1.7 AND 1.5
INCHES. THE SHARP INCREASE IN MOISTURE EXPECTED LATER ON WEDNESDAY
MAY CAUSE PRECIPITABLE WATER TO PEAK AT NEAR 2.4 INCHES BY
WEDNESDAY EVENING. MOISTURE WILL THEN DECREASE RAPIDLY BY THURSDAY
AFTERNOON INTO FRIDAY...WITH PRECIPITABLE WATER FALLING FROM NEAR
1.9 INCHES ON THURSDAY TO 1.4 INCHES ON FRIDAY.
FOR TODAY AND TUESDAY...THE OVERALL WEATHER IS EXPECTED TO BE
RELATIVELY DRY AND HAZY. ISOLATED SHOWERS AND BRIEF AND ISOLATED
AFTERNOON CONVECTION ACROSS WESTERN PR IS EXPECTED. WEDNESDAY IS
EXPECTED TO HAVE THE SIGNIFICANT RAINFALL...WITH SOME OF THE MODEL
GUIDANCE SUGGESTING OVER 2 TO NEARLY 3 INCHES OF RAIN FOR EASTERN
PR. THE EGDI ALGORITHM IS SUGGESTING ISOLATED TO SCATTERED
THUNDERSTORMS POSSIBLE ON WEDNESDAY AND WEDNESDAY EVENING...BUT
THE RISK DECREASES RAPIDLY ON THURSDAY. HOWEVER...THE SEVERITY
INDEX DOES NOT INDICATE THE POTENTIAL OF VERY SEVERE STORMS. HAZY
CONDITIONS ARE EXPECTED AGAIN ON THURSDAY INTO FRIDAY WITH MUCH
MORE MODEST AMOUNTS OF RAIN FORECAST.
THE 5-DAY RAINFALL TOTALS ARE FORECAST TO BE NEAR 3 INCHES ACROSS
EASTERN PR...AND 1.75 TO 2 INCHES ACROSS WESTERN PR. FOR THE
USVI...BETWEEN 0.5 AND 1 INCH IS FORECAST. WEDNESDAY AFTERNOON AND
NIGHT IS EXPECTED TO BE THE RAINIEST PERIOD IN THE NEXT 5 DAYS DUE
TO THE ARRIVAL OF THE TROPICAL WAVE.
ALAMO/GALVEZ...WPC (USA)
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