TROPICAL DISCUSSION - INTERNATIONAL DESKS
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
931 AM EDT THU JUL 25 2024

WEEKLY DISCUSSION FOR PUERTO RICO AND THE USVI JUl 25/12UTC: A
BROAD SFC HIGH PRESSURE CENTERED OVER THE WEST CENTRAL ATLANTIC
WILL DOMINATE THE ATLANTIC FOR THE NEXT SEVERAL DAYS. THIS HIGH
PRESSURE WILL KEEP EASTERLY WINDS OVER THE CARIBBEAN FOR THE NEXT
SEVERAL DAYS AS WELL. THE SFC HIGH WILL SLOWLY MOVE EAST THROUGH
THE NEXT SEVERAL DAYS...AS A SFC LOW MOVES INTO THE WESTERN
ATLANTIC AND DRIFTS NORTHEAST...BUT THIS LOW WILL NOT HAVE ANY
IMPACT ON THE OVERALL WIND FLOW OR WEATHER PATTERN IN PR...AS THE
SFC HIGH WILL DOMINATE. ADDITIONALLY...THERE IS A RELATIVELY DENSE
PLUME OF SAHARAN DUST MOVING INTO THE CARIBBEAN...WHICH WILL
AFFECT PR/USVI THROUGH SUNDAY...AND WITH IT THERE WILL BE NEAR TO
BELOW NORMAL MOISTURE. FROM MONDAY INTO TUESDAY...CLEANER AIR WILL
MOVE IN AND ALLOW FOR PATCHES OF MOISTURE TO PASS THROUGH THE
LOCAL ISLANDS...BUT ANOTHER PLUME OF SAHARAN DUST WILL ONCE AGAIN
MOVE IN LATE TUESDAY ONWARD. HOWEVER...A TROPICAL WAVE WILL BE
MOVING IN ON WEDNESDAY...CAUSING A BRIEF INCREASE IN MOISTURE OVER
THE ISLANDS...BUT WITH SAHARAN DUST OVER THE AREA.

IN THE UPPER LEVELS...THERE IS A STRONG TUTT OVER THE WESTERN
TROPICAL ATLANTIC...JUST NORTH OF THE TURKS AND CAICOS...CAUSING
SOUTHWESTERLY WINDS IN THE UPPER LEVELS ACROSS PR/USVI. THIS TUTT
WILL MEANDER OVER THE BAHAMAS INTO CUBA AS IT WEAKENS GRADUALLY
THIS WEEKEND. HOWEVER...THE COMBINATION OF THE RELATIVELY DRY AIR
AND THE SAHARAN DUST...WITH A STRONG MID LEVEL HIGH PRESSURE NORTH
OF PR/USVI...WILL CAUSE A STRONG TRADE WIND INVERSION TO PERSIST
INTO SATURDAY OVER THE LOCAL ISLANDS. THE RAINFALL PATTERN OVER
THE NEXT SEVERAL DAYS WILL BE TYPICAL IN TERMS OF LOCATION...BUT
WITH LIMITED RAINFALL AMOUNTS. AS OF NOW...THE DRIEST DAY IS
EXPECTED TO BE FRIDAY INTO SATURDAY MORNING...AND THE RAINIEST
BEING ON WEDNESDAY INTO EARLY THURSDAY...WITH THE EXPECTED PASSAGE
OF A TROPICAL WAVE. THAT SAID...WEDNESDAY IS FAR IN THE FORECAST
PERIOD...SO CONFIDENCE IS LOW.

OVERALL...CONSIDERING THE SAHARAN DUST...NEAR TO BELOW NORMAL
MOISTURE AND THE STRONG SFC AND MID LEVEL HIGH PRESSURES...A
RELATIVELY TYPICAL BUT UNREMARKABLE RAINFALL PATTERN WOULD BE
EXPECTED FOR THE UPCOMING WEEK. THEREFORE...BRIEF SHOWERS ACROSS
THE USVI AND EASTERN PR GENERALLY IN THE OVERNIGHT AND EARLY
MORNING HOURS...THEN AFTERNOON CONVECTION ACROSS PORTIONS OF
WESTERN PR IS THE PATTERN EXPECTED...WITH VARYING AMOUNTS OF RAIN
EACH DAY WHICH WILL BE STRONGLY CORRELATED WITH THE AVAILABLE
MOISTURE ANY GIVEN DAY...BUT AS OF THE LATEST GUIDANCE...THE
FORECAST DAILY RAINFALL IS NOT EXPECTED TO BE PARTICULARLY
HAZARDOUS.


ALAMO...WPC (USA)