TROPICAL DISCUSSION - INTERNATIONAL DESKS
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
728 AM EST WED NOV 29 2023

PRELIMINARY DISCUSSION FOR PUERTO RICO AND THE USVI NOV 29/12UTC:
MOSTLY FAIR WEATHER WITH BRIEF SHOWERS ACROSS EASTERN PR AND THE
USVI ARE EXPECTED FOR THE NEXT 5 DAYS...THOUGH SHALLOW CONVECTION
IS POSSIBLE ACROSS A FEW AREAS OF WESTERN PR IN THE AFTERNOONS.
THE RAINFALL AMOUNTS ARE EXPECTED TO BE MODEST EACH DAY AS THE
AVAILABLE MOISTURE IS FORECAST TO BE BE BELOW NORMAL THROUGH EARLY
FRIDAY...THEN MOISTURE WILL BE BETWEEN NEAR NORMAL TO BELOW NORMAL
FROM FRIDAY EVENING AND THROUGH THE WEEKEND.

A SURFACE HIGH PRESSURE WILL START TO MAKE ITS WAY INTO THE
WESTERN ATLANTIC TODAY AS IT MOVES EAST. THE SURFACE HIGH PRESSURE
IS EXPECTED TO ELONGATE AND EXPAND INTO THE CENTRAL ATLANTIC OVER
THE NEXT SEVERAL DAYS. THIS WILL KEEP THE EASTERLY WINDS OVER THE
LOCAL ISLANDS TODAY INTO EARLY THURSDAY...BUT COULD BE EAST
NORTHEASTERLY BY LATE THURSDAY INTO SATURDAY. IN THE MID
LEVELS...A HIGH PRESSURE WILL DOMINATE AND PROMOTE STABILITY OVER
THE CARIBBEAN REGION THROUGH THE REST OF THE WEEK AND INTO THE
WEEKEND. IN THE UPPER LEVELS...A RIDGE WILL PERSIST OVER THE
NORTHEASTERN CARIBBEAN TODAY...BUT A TROUGH WILL DEVELOP ACROSS
THE SOUTHEAST CARIBBEAN...BUT NO IMPACT IS EXPECTED ACROSS PR/USVI
AS THE AXIS WOULD BE TO THE EAST OF THE LOCAL ISLANDS AND THERE IS
A STRONG MID LEVEL HIGH PRESSURE. ACCORDING TO THE LATEST
GUIDANCE...THE UPPER LEVEL WINDS WILL BE LIGHT AND NORTHERLY
TODAY...THE WINDS WILL BECOME WESTERLY LATE TONIGHT INTO
THURSDAY...THEN NORTHERLY AGAIN LATE FRIDAY INTO THE WEEKEND AS A
STRONG HIGH PRESSURE MOVES INTO THE WESTERN CARIBBEAN.

THE EGDI FORECAST ALGORITHM IS CONTINUES TO SUGGEST THAT SHALLOW
CONVECTION IS POSSIBLE BUT THERE IS NO INDICATION THAT
THUNDERSTORMS ARE TO BE EXPECTED OVER THE NEXT 5 DAYS. THIS IS
CONSISTENT WITH THE EXPECTED IMPACT FROM A STRONG MID LEVEL HIGH
PRESSURE DOMINATING THE AREA. THE TWIN ALGORITHM CONTINUES TO
SUGGEST THAT A TRADE WIND INVERSION WILL BE PRESENT AT AROUND THE
900-800 HPA LEVEL THROUGH MOST OF THE NEXT SEVERAL DAYS...ALSO
FAVORING MOST OF THE SHOWER ACTIVITY BEING ADVECTIVE AND
CONVECTION TO BE SHALLOW. THE AVAILABLE MOISTURE IS EXPECTED TO BE
BELOW NORMAL THROUGH EARLY FRIDAY...WITH PRECIPITABLE WATER
GENERALLY BETWEEN 1.1 AND 1.4 INCHES. AN INCREASE IN MOISTURE
COULD OCCUR LATE FRIDAY THROUGH EARLY SUNDAY...WITH PRECIPITABLE
WATER RANGING FROM 1.5 TO ABOUT 1.7 INCHES...THOUGH BRIEF DRY
PATCHES ARE POSSIBLE DURING THAT PERIOD. THEREFORE...A SLIGHT
INCREASE IN SHOWER ACTIVITY COULD BE EXPECTED DURING THE OVERNIGHT
HOURS FROM FRIDAY INTO SATURDAY THEN FROM SATURDAY INTO
SUNDAY...BUT IT WOULD STILL BE GENERALLY ADVECTIVE SHOWERS
AFFECTING EASTERN PUERTO RICO AND THE USVI.

THE 5-DAY TOTAL RAINFALL FORECAST SUGGESTS THAT EASTERN AND
NORTHEASTERN PUERTO RICO WOULD HAVE AROUND OR JUST UNDER AN INCH
OF RAIN. SMALL PORTIONS OF WESTERN PR ARE FORECAST OVER AN INCH OF
RAIN THROUGH THE 5-DAY PERIOD...WHILE THE USVI...VIEQUES AND
CULEBRA ARE FORECAST BETWEEN 0.25 AND 0.75 INCHES.


ALAMO...WPC (USA)