263
FXCA62 TJSJ 120759
AFDSJU
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN JUAN PR
359 AM AST FRI SEP 12 2025
KEY MESSAGES
* AFTERNOON SHOWERS AND THUNDERSTORMS ARE EXPECTED FOR CENTRAL AND
WESTERN PUERTO RICO, DUE TO THE ABUNDANT MOISTURE AND DIURNAL
HEATING EFFECTS.
* FOR THE U.S. VIRGIN ISLANDS; WARM TEMPERATURES AND MAINLY FAIR
WEATHER CONDITIONS WILL PREVAIL TODAY, UNDER MOSTLY SUNNY TO
PARTLY CLOUDY SKIES.
* HOT TEMPERATURES WILL PERSIST DURING THE NEXT SEVERAL DAYS
ACROSS THE REGION. A HEAT ADVISORY IS IN EFFECT FROM 10 AM TO 4
PM AST FOR THE URBAN AND COASTAL AREAS OF PUERTO RICO, VIEQUES,
CULEBRA, AND ALL OF THE U.S. VIRGIN ISLANDS.
* THERE IS A LOW RISK OF RIP CURRENTS FOR ALL BEACHES OF THE LOCAL
ISLANDS.
SHORT TERM...TODAY THROUGH SUNDAY
MOSTLY TRANQUIL CONDITIONS WERE OBSERVED DURING THE NIGHT HOURS
ACROSS THE ISLANDS. SOME SHOWERS MANAGED TO REACH ST. JOHN AND
SOUTHEASTERN PUERTO RICO, BUT ACCUMULATIONS WERE NOT SIGNIFICANT.
SKIES WERE MOSTLY CLEAR, WITH SOME HIGH CLOUDS MOVING IN.
TEMPERATURES WERE JUST A TAD COOLER THAN YESTERDAY, BUT STILL IN THE
LOW 80S IN THE VIRGIN ISLANDS, AND IN THE 70S IN PUERTO RICO.
A COUPLE OF TROUGHS, ONE TO THE NORTHEAST, AND ONE WELL NORTHWEST OF
THE ISLANDS WILL MAINTAIN THE TRADE WINDS WEAKER FOR TODAY AND
SATURDAY. IN GENERAL, THE MORNINGS WILL BE MOSTLY PLEASANT, WITH
PASSING SHOWERS REACHING THE VIRGIN ISLANDS, VIEQUES AND CULEBRA AND
EASTERN PUERTO RICO AT TIMES, ALTHOUGH NO SIGNIFICANT RAINFALL
ACCUMULATION IS ANTICIPATED. IN THE AFTERNOON, NEAR NORMAL MOISTURE
LEVELS AND STRONG DIURNAL HEATING WILL LEAD TO ANOTHER ACTIVE
AFTERNOON. SHOWERS AND THUNDERSTORMS ARE EXPECTED TO DEVELOP ALONG
THE CORDILLERA CENTRAL, AND WITH A WEAK STEERING FLOW, THESE SHOWERS
WILL THEN SPREAD INTO THE WEST AND NORTHWEST OF PUERTO RICO, AS WELL
AS OVER PORTIONS OF THE SAN JUAN METRO AREA. SHOWERS COULD ALSO FIRE
UP IN THE WESTERN PORTIONS OF ST. CROIX, STREAMING TOWARD THE
CARIBBEAN SEA. THE HIGHEST RISK OF FLOODING IS FOR THE INTERIOR,
NORTHWEST, AND THE SAN JUAN METRO AREA, WHERE URBAN AND SMALL STREAM
FLOODING COULD DEVELOP. ALSO, FREQUENT LIGHTNING AND GUSTY WINDS ARE
EXPECTED WITHIN THE STRONGEST THUNDERSTORMS.
SOME DRIER AIR IS EXPECTED EARLY ON SUNDAY, LEADING TO FAIR WEATHER
FOR MOST OF THE NORTHEAST CARIBBEAN, BUT THEN A TROPICAL WAVE WILL
APPROACH THE VIRGIN ISLANDS, WITH A HIGHER CHANCE OF SHOWERS IN THE
VICINITY OF SAINT CROIX IN THE AFTERNOON HOURS. THE MOISTURE FIELD
OF THE WAVE WILL SPREAD WESTWARD, ALSO INCREASING THE FREQUENCY OF
SHOWERS FOR THE REST OF THE VIRGIN ISLANDS AND EASTERN PUERTO RICO.
WINDS WILL INCREASE TOO, COMING FROM THE EAST SOUTHEAST AT SPEEDS OF
20 TO 25 MPH.
TEMPERATURES AT 925 MB ARE JUST A TAD COOLER THAN YESTERDAY, BUT
STILL, WELL ABOVE NORMAL HEAT INDICES WILL PREVAIL. A HEAT ADVISORY
IS IN EFFECT FOR MOST OF PUERTO RICO AND ALL OF THE VIRGIN ISLANDS.
A HEAT ADVISORY MEANS THAT PEOPLE SENSIBLE TO HEAT WILL BE AFFECTED,
ESPECIALLY THOSE WITHOUT EFFECTIVE COOLING OR ADEQUATE HYDRATION.
LONG TERM...MONDAY THROUGH FRIDAY
A TROPICAL WAVE IS FORECAST TO MOVE OVER PUERTO RICO AND THE U.S.
VIRGIN ISLANDS, BRINGING INCREASED MOISTURE AND A HIGH LIKELIHOOD OF
SHOWERS AND THUNDERSTORMS. THE LATEST PRECIPITABLE WATER GUIDANCE
INDICATES NORMAL TO ABOVE-NORMAL VALUES (2.00 TO 2.25 INCHES),
SUGGESTING A WET PATTERN WILL PERSIST THROUGH TUESDAY. THE U.S.
VIRGIN ISLANDS SHOULD ANTICIPATE SHOWERS AND ISOLATED THUNDERSTORMS,
PARTICULARLY FROM THE MORNING INTO THE AFTERNOON. IN PUERTO RICO,
SHOWERS AND ISOLATED THUNDERSTORMS ARE EXPECTED OVER THE EASTERN
MUNICIPALITIES DURING THE MORNING, WITH AFTERNOON CONVECTIVE
ACTIVITY SHIFTING TO THE WESTERN AND NORTHWESTERN MUNICIPALITIES DUE
TO A COMBINATION OF DAYTIME HEATING AND LOCAL EFFECTS.
THIS WET TREND IS EXPECTED TO CONTINUE FROM WEDNESDAY THROUGH THE
REST OF THE WEEK, AS AN UPPER-LEVEL TROUGH LOCATED NORTHEAST OF THE
REGION MOVES SOUTHEAST. A SECOND TROPICAL WAVE APPROACHING THE AREA
WILL COMBINE WITH THE AVAILABLE MOISTURE FROM THE UPPER-LEVEL-
TROUGH, FURTHER ENHANCING THE POTENTIAL FOR ADDITIONAL SHOWERS AND
THUNDERSTORMS ACROSS THE ISLANDS. THEREFORE, THE RISK OF EXCESSIVE
RAINFALL LEADING TO URBAN AND SMALL STREAM FLOODING REMAINS
ELEVATED. THERE IS ALSO A LIMITED RISK OF FREQUENT LIGHTNING
ACCOMPANYING THE STRONGEST THUNDERSTORMS.
DESPITE THE EXPECTED WEATHER FOR THE LONG-TERM PERIOD, THE 925 MB
TEMPERATURE IS EXPECTED TO REMAIN ABOVE-NORMAL AT THE BEGINNING OF
THE WEEK. HOWEVER, AS THE WEEK PROGRESSES, TEMPERATURES WILL BECOME
SLIGHTLY COOLER DUE TO THE INCREASED RAINFALL. HIGHS WILL GENERALLY
BE IN THE MID TO UPPER 80S ALONG COASTAL AND URBAN AREAS, AND IN THE
UPPER 70S TO LOW 80S IN THE HIGHER ELEVATIONS. RESIDENTS AND
VISITORS ARE ADVISED TO MONITOR WEATHER CONDITIONS AND PLAN ANY
OUTDOOR ACTIVITIES ACCORDINGLY FOR THE UPCOMING WEEK.
AVIATION
(06Z TAFS)
MAINLY VFR CONDITIONS EXPECTED TO PREVAIL. SHRA WILL MOVE IN THE
VICINITY OF THE USVI TERMINALS, BUT LIMITED, IF ANY, IMPACTS TO
OPERATIONS ARE EXPECTED. AFTER 17Z, ANOTHER ROUND OF STRONG
CONVECTION IS EXPECTED FOR THE CORDILLERA CENTRAL, REACHING TJSJ
AND TJBQ AT TIMES. PERIODS OF REDUCED VIS AND LOW CEILINGS ARE
EXPECTED AS WELL. WINDS WILL BE LIGHTER, OUT OF THE ESE AT 7-11
KTS.
MARINE
A SURFACE HIGH PRESSURE ACROSS THE CENTRAL ATLANTIC AND A FRONT OVER
THE WESTERN ATLANTIC WILL PROMOTE LIGHT TO MODERATE EAST TO SOUTHEAST
WINDS THROUGH THE WEEKEND. AFTERNOON SHOWERS AND THUNDERSTORMS ARE LIKELY
EACH DAY, PARTICULARLY OVER THE NORTHWESTERN COASTAL WATERS OF
PUERTO RICO AND OVER THE MONA PASSAGE.
BEACH FORECAST
A LOW RISK OF RIP CURRENTS IS EXPECTED TO CONTINUE THROUGH THE
WEEKEND. HOWEVER, EVEN WITH A LOW RISK, LIFE- THREATENING RIP
CURRENTS CAN STILL OCCUR NEAR GROINS, JETTIES, REEFS, AND PIERS,
SO BEACHGOERS ARE ADVISED TO EXERCISE CAUTION AT ALL TIMES. THE
RIP CURRENT RISK IS FORECAST TO INCREASE TO MODERATE AGAIN BY
EARLY NEXT WEEK. ADDITIONAL HAZARDS INCLUDE: ISOLATED AFTERNOON
THUNDERSTORMS AND AN ELEVATED TO SIGNIFICANT HEAT RISK. REMEMBER:
IF YOU HEAR THUNDER, SEEK SHELTER INDOORS IMMEDIATELY, AND BE SURE
TO STAY WELL HYDRATED.
SJU WATCHES/WARNINGS/ADVISORIES
PR...HEAT ADVISORY FROM 10 AM THIS MORNING TO 4 PM AST THIS AFTERNOON
FOR PRZ001>005-007-008-010>013.
VI...HEAT ADVISORY FROM 10 AM THIS MORNING TO 4 PM AST THIS AFTERNOON
FOR VIZ001-002.
AM...NONE.
SHORT TERM/AVIATION...ERG
LONG TERM....GRS
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