TROPICAL DISCUSSION - INTERNATIONAL DESKS
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
813 AM EDT MON OCT 02 2023

PRELIMINARY DISCUSSION FOR PUERTO RICO AND THE USVI OCT 02/12UTC:
TROPICAL STORM PHILIPPE IS STILL LOCATED JUST EAST OF THE LEEWARD
ISLANDS. PHILIPPE WILL CAUSE PUERTO RICO AND THE U.S. VIRGIN
ISLANDS TO BE UNDER A PERSISTENT NORTHEAST TO NORTHERLY WIND FLOW
TODAY AND TUESDAY. AS PHILIPPE MOVES NORTH...THE LOCAL WINDS WILL
BECOME WEAKER AND HAVE A STRONG WESTERLY COMPONENT...FROM
NORTHWESTERN TO SOUTHWESTERN WINDS ON WEDNESDAY...THEN
SOUTHWESTERN ON THURSDAY...BECOMING SOUTHERLY LATER ON FRIDAY AND
THROUGH THE WEEKEND. THIS WIND PATTERN...COMBINED WITH THE
AVAILABLE MOISTURE WILL HAVE AN IMPACT ON THE AMOUNTS AND LOCATION
OF THE RAINFALL OVER PR/USVI. UNDER THE NORTHEASTERLY WINDS...THE
MAX RAINFALL IS EXPECTED ACROSS NORTHEASTERN PR DUE TO SHOWERS IN
BANDS WHILE AFTERNOON CONVECTION COULD AFFECT SOUTHWEST PR.
TUESDAY IS EXPECTED TO HAVE A MUCH STRONGER NORTHERLY WIND
COMPONENT...THEREFORE THE MAX RAINFALL IS EXPECTED ACROSS THE
INTERIOR TO SOUTHERN PR IN THE AFTERNOON. AS WINDS SHIFT TO THE
WEST ON WEDNESDAY...THE EASTERN HALF OF PR IS EXPECTED TO HAVE THE
MORE SIGNIFICANT RAIN...WHILE WESTERN PR REMAINS RELATIVELY DRY.
THURSDAY AND FRIDAY...UNDER SOUTHWESTERLY TO SOUTHERLY
WINDS...WILL HAVE THE MAX RAINFALL ACROSS THE NORTHERN
MUNICIPALITIES AS THE AFTERNOON SEA BREEZE CONVERGENCE COULD
DEVELOP ACROSS THE NORTHERN COASTAL SECTIONS. WITH RESPECT TO THE
USVI...MOST OF THE RAINFALL TODAY AND TUESDAY MAY BE DUE TO
PASSING SHOWERS FROM OUTER BANDS OF PHILIPPE. HOWEVER...AS THE
WINDS SHIFT TO THE WEST...AN AREA OF CONVERGENCE MAY OCCUR NEAR
THE ISLANDS...ESPECIALLY ON WEDNESDAY...WHICH COULD CAUSE
SIGNIFICANT RAIN ACROSS THE NORTHERN USVI. BRIEF SHOWERS WOULD BE
EXPECTED ON THURSDAY AND FRIDAY ACROSS THE USVI AS WELL...THOUGH
THURSDAY LOOKS A BIT WETTER THAN FRIDAY.

THERE IS STILL CONSIDERABLE UNCERTAINTY IN THE RAINFALL FORECAST.
THE LOCAL WIND DIRECTION AND SPEED...CONVERGENCE ZONES...AND
AVAILABLE MOISTURE...ARE GREATLY INFLUENCED BY THE EVENTUAL TRACK
OF TROPICAL STORM PHILIPPE...WHICH HAS BEEN A CHALLENGE IN ITSELF.
THAT SAID...THE RAINFALL FORECAST AND REASONING IS BASED ON THE
LATEST MODEL GUIDANCE AND THE TRACK FORECAST FOR PHILIPPE BY THE
NATIONAL HURRICANE CENTER. IN ADDITION...THERE SEEMS TO BE A BIT
MORE AGREEMENT AMONG THE MODEL GUIDANCE WITH REGARDS TO THE TRACK
OF PHILIPPE.

BASED ON THE CURRENT FORECAST...THE 5-DAY RAINFALL TOTAL IS
FORECAST TO BE AROUND 3.5 TO 4 INCHES
ACROSS THE NORTHERN TO NORTHEASTERN COASTAL SECTIONS OF PR...WHILE
CENTRAL TO SOUTHWESTERN PR COULD OBSERVE BETWEEN 1.5 AND 2 INCHES.
THE USVI ARE FORECAST AROUND 1 TO 2 INCHES...WITH THE NORTHERN
ISLANDS ON THE HIGHER END OF THE RANGE.


ALAMO...WPC (USA)