486
FXCA62 TJSJ 231120 CCA
AFDSJU
AREA FORECAST DISCUSSION...CORRECTED
NATIONAL WEATHER SERVICE SAN JUAN PR
720 AM AST FRI OCT 23 2026
...NEW KEY MESSAGES, SHORT TERM, LONG TERM, AVIATION, MARINE,
BEACH FORECAST...
KEY MESSAGES
ISSUED AT 350 AM AST FRI OCT 23 2026
* SHOWERS AND THUNDERSTORMS WILL CONTINUE THROUGH THE WEEKEND,
WITH LOCALLY HEAVY RAINFALL THAT COULD CAUSE URBAN AND SMALL-
STREAM FLOODING, RAPID RIVER RISES, AND ISOLATED FLASH FLOODING.
SATURATED, STEEP SLOPES MAY ALSO BE SUSCEPTIBLE TO LANDSLIDES.
* AFTERNOON CONVECTION WILL FAVOR INTERIOR, NORTHERN, AND WESTERN
PUERTO RICO, WITH PASSING SHOWERS AFFECTING WINDWARD AREAS
OVERNIGHT AND DURING THE MORNING. SOME IMPROVEMENT IS POSSIBLE
SUNDAY, THOUGH UNCERTAINTY REMAINS ABOUT HOW MUCH DRYING WILL
OCCUR.
* DANGEROUS BREAKING WAVES AND LIFE-THREATENING RIP CURRENTS WILL
AFFECT EXPOSED NORTHERN BEACHES TODAY AND SATURDAY. A HIGH SURF
ADVISORY IS IN EFFECT TODAY FOR NORTH- CENTRAL PUERTO RICO,
WITH BREAKING WAVES AROUND 10 FEET. ADDITIONAL SWELL PULSES MAY
KEEP SWIMMING CONDITIONS HAZARDOUS INTO EARLY NEXT WEEK.
* SEAS OF 5 TO 6 FEET ACROSS PORTIONS OF THE ATLANTIC WATERS AND
MONA PASSAGE WARRANT CAUTION FOR SMALL CRAFT. THUNDERSTORMS
MAY PRODUCE LOCALLY GUSTY WINDS, LIGHTNING, AND REDUCED
VISIBILITY.
* WARM AND HUMID CONDITIONS WILL PERSIST, WITH HEAT IMPACTS
POTENTIALLY INCREASING THIS WEEKEND INTO EARLY NEXT WEEK,
PARTICULARLY IN COASTAL, LOW-LYING, AND URBAN AREAS.
SHORT TERM(TODAY THROUGH SUNDAY)
ISSUED AT 350 AM AST FRI OCT 23 2026
CLOUDY SKIES PREVAILED ACROSS MOST OF PUERTO RICO OVERNIGHT,
WHILE THE U.S. VIRGIN ISLANDS REMAINED MOSTLY CLEAR TO PARTLY
CLOUDY. SHOWERS AND THUNDERSTORMS WERE CONCENTRATED OVER THE
CARIBBEAN WATERS AND MONA PASSAGE, WITH LITTLE OR NO RAINFALL OVER
LAND ASIDE FROM ISOLATED WINDWARD SHOWERS. TEMPERATURES RANGED
FROM THE LOWER TO MID-70S ACROSS PORTIONS OF NORTHERN PUERTO RICO
TO THE LOWER 80S ALONG THE SOUTHERN COAST AND ACROSS THE U.S.
VIRGIN ISLANDS. MOUNTAIN TEMPERATURES FELL INTO THE UPPER 60S.
A MOIST PATTERN WILL SUPPORT SHOWERS AND THUNDERSTORMS THROUGH
THE WEEKEND, THOUGH MODEL DIFFERENCES CREATE UNCERTAINTY IN
RAINFALL COVERAGE, ESPECIALLY ON SUNDAY. THE LATEST 00Z GFS
MAINTAINS PRECIPITABLE WATER VALUES NEAR 1.9-2.2 INCHES,
GENERALLY NEAR OR ABOVE NORMAL. THE EARLIER GFS-ECMWF COMPARISON
SHOWS A DRIER ECMWF SOLUTION BY SUNDAY. TODAY, A SHORTWAVE TROUGH
AND AVAILABLE MOISTURE WILL FAVOR MORNING SHOWERS AND ISOLATED
THUNDERSTORMS OVER THE CARIBBEAN WATERS AND SOUTHERN PUERTO RICO,
FOLLOWED BY AFTERNOON CONVECTION ACROSS INTERIOR, NORTHERN, AND
WESTERN PUERTO RICO. CLOUD COVER MAY LIMIT DAYTIME HEATING AND
MAKE AFTERNOON DEVELOPMENT MORE LOCALIZED.
A SURFACE HIGH OVER THE CENTRAL ATLANTIC AND A LOW TO THE
NORTHWEST WILL MAINTAIN AN EAST-SOUTHEAST TO SOUTHEAST FLOW
THROUGH SATURDAY. PASSING SHOWERS WILL AFFECT EASTERN PUERTO RICO
AND THE U.S. VIRGIN ISLANDS OVERNIGHT AND DURING THE MORNING, WITH
ADDITIONAL CONVECTION DEVELOPING OVER PUERTO RICO EACH AFTERNOON.
GFS 925 MB WINDS INCREASE TO AROUND 15-17 KT, SUGGESTING FASTER-
MOVING SHOWERS; HOWEVER, REPEATED DEVELOPMENT ALONG LOCAL
CONVERGENCE BOUNDARIES COULD STILL PRODUCE LOCALLY HEAVY RAINFALL.
URBAN AND SMALL STREAM FLOODING, RAPID RIVER RISES, AND LOCALIZED
FLASH FLOODING REMAIN POSSIBLE WHERE HEAVIER RAINFALL PERSISTS.
ADDITIONAL RAINFALL COULD ALSO INCREASE LANDSLIDE SUSCEPTIBILITY
ON SATURATED, STEEP SLOPES.
BY SUNDAY, RISING UPPER-LEVEL HEIGHTS, WARMING 500 MB
TEMPERATURES, AND WEAKER MID-LEVEL LAPSE RATES SUGGEST INCREASING
STABILITY AND LESS FAVORABLE CONDITIONS FOR DEEP CONVECTION.
NEVERTHELESS, LINGERING MOISTURE AND LOCAL EFFECTS WILL SUPPORT
PASSING SHOWERS AND LOCALIZED AFTERNOON THUNDERSTORMS. THE EXTENT
OF IMPROVEMENT REMAINS UNCERTAIN BECAUSE MOISTURE FORECASTS
DIFFER. WARM AND HUMID CONDITIONS WILL CONTINUE, WITH LOCALIZED
HEAT IMPACTS PRIMARILY AFFECTING HEAT-SENSITIVE INDIVIDUALS
WITHOUT ADEQUATE COOLING OR HYDRATION.
LONG TERM(MONDAY THROUGH FRIDAY)
ISSUED AT 350 AM AST FRI OCT 23 2026
A GRADUAL DRYING TREND IS EXPECTED ACROSS PUERTO RICO AND THE U.S.
VIRGIN ISLANDS DURING THE LONG TERM PERIOD, ALTHOUGH PERIODS OF
UNSETTLED WEATHER MAY PERSIST THROUGH WEDNESDAY BEFORE MORE
FAVORABLE CONDITIONS DEVELOP THURSDAY AND FRIDAY. THE LATEST MODEL
GUIDANCE SUGGESTS PRECIPITABLE WATER VALUES DECREASING FROM AROUND
1.8 TO 2.0 INCHES EARLY IN THE PERIOD TO 1.2 TO 1.5 INCHES,
POTENTIALLY NEAR OR BELOW THE 25TH PERCENTILE OF THE LATE-OCTOBER
VALUES. DESPITE THE DECREASE IN MOISTURE, DAYTIME HEATING, SEA-
BREEZE CONVERGENCE, AND LOCAL TERRAIN EFFECTS WILL CONTINUE TO
SUPPORT AFTERNOON SHOWERS AND ISOLATED THUNDERSTORMS, PARTICULARLY
ACROSS INTERIOR AND WESTERN PUERTO RICO.
ON MONDAY, PERIODS OF SUNSHINE SHOULD PREVAIL ACROSS MANY AREAS,
ALTHOUGH LOCALLY HEAVY AFTERNOON SHOWERS COULD STILL PRODUCE PONDING
OF WATER ON ROADS AND ISOLATED URBAN OR SMALL-STREAM FLOODING.
TUESDAY AND WEDNESDAY MAY REMAIN SOMEWHAT UNSETTLED AS COOLING
TEMPERATURES ALOFT AND SLIGHTLY STEEPER MID-LEVEL LAPSE RATES
MAINTAIN SUFFICIENT INSTABILITY FOR CONVECTIVE DEVELOPMENT DESPITE
INCREASING MID-LEVEL DRYNESS. THIS COULD RESULT IN AFTERNOON SHOWERS
AND THUNDERSTORMS ACROSS INTERIOR PUERTO RICO, WITH SOME ACTIVITY
POTENTIALLY AFFECTING NORTHERN SECTIONS WITH THE PREVAILING
SOUTHEASTERLY WIND FLOW. BRIEF PASSING SHOWERS MAY ALSO REACH
WINDWARD AREAS AND THE U.S. VIRGIN ISLANDS. WHILE WIDESPREAD
RAINFALL IS NOT ANTICIPATED, LOCALIZED DOWNPOURS AND LIGHTNING COULD
AFFECT OUTDOOR ACTIVITIES. MEANWHILE, PERIODS OF SUNSHINE COMBINED
WITH LINGERING LOW-LEVEL HUMIDITY MAY CONTRIBUTE TO LOCALLY ELEVATED
HEAT INDICES, PARTICULARLY ACROSS COASTAL AND URBAN AREAS.
BY THURSDAY AND FRIDAY, GENERALLY FAIR WEATHER WITH LONGER PERIODS
WITH CLEAR SKIES AND REDUCED SHOWER COVERAGE ACROSS THE ISLANDS.
ALTHOUGH ISOLATED AFTERNOON CONVECTION REMAINS POSSIBLE OVER
INTERIOR AND WESTERN PUERTO RICO, THE POTENTIAL FOR WIDESPREAD HEAVY
RAINFALL AND FLOODING SHOULD REMAIN LOW. THESE DAYS CURRENTLY OFFER
THE MOST FAVORABLE CONDITIONS FOR OUTDOOR ACTIVITIES, ESPECIALLY
DURING DAYLIGHT HOURS. HOWEVER, PEOPLE DOING PROLONGATED OUTDOOR
WORK SHOULD REMAIN MINDFUL OF POTENTIAL HEAT STRESS.
AVIATION
(06Z TAFS)
ISSUED AT 350 AM AST FRI OCT 23 2026
MAINLY VFR CONDS EXPECTED TODAY. SHRA/TSRA OVER THE CARIBBEAN
WATERS AND MONA PASSAGE MAY BRING BRIEF MVFR CONDITIONS TO TJPS
EARLY THIS MORNING. AFTERNOON CONVECTION WILL FAVOR INTERIOR,
NORTHERN, AND WESTERN PR, WITH POTENTIAL IMPACTS AT TJBQ AND TJSJ,
INCLUDING BRIEF MVFR/IFR CONDITIONS, MOUNTAIN OBSCURATION, AND
GUSTY WINDS. PASSING SHRA MAY AFFECT TIST/TISX INTERMITTENTLY.
LIGHT SE WINDS WILL BECOME E-ESE AROUND 10-15 KT AFTER 23/14Z,
WITH SEA BREEZE VARIATIONS AND HIGHER GUSTS NEAR TSRA.
MARINE
ISSUED AT 350 AM AST FRI OCT 23 2026
MODERATE TO LOCALLY FRESH (15-20 KT) EAST TO SOUTHEAST WINDS WILL
PREVAIL THROUGH THE WEEKEND AS THE SURFACE PRESSURE GRADIENT
TIGHTENS ACROSS THE REGIONAL WATERS. A NORTH-NORTHWESTERLY SWELL
WILL MAINTAIN SEAS BETWEEN 5 AND 7 FEET ACROSS THE ATLANTIC WATERS
AND THE MONA PASSAGE TODAY, FOLLOWED BY REINFORCING NORTHERLY SWELL
PULSES THROUGH EARLY NEXT WEEK. SMALL CRAFT ADVISORIES REMAIN IN
EFFECT FOR THE ATLANTIC WATERS AND THE MONA PASSAGE THROUGH AT LEAST
SATURDAY. ISOLATED THUNDERSTORMS WITH SCATTERED SHOWERS ARE EXPECTED
TO CONTINUE ACROSS THE CARIBBEAN AND WESTERN WATERS OF PR TODAY,
WHERE LOCALLY HIGHER SEAS AND STRONG GUSTY WINDS ARE POSSIBLE.
BEACH FORECAST
ISSUED AT 350 AM AST FRI OCT 23 2026
THE ARRIVAL OF A LONG-PERIOD (12-14 SECONDS) NORTH-NORTHWEST SWELL
TODAY WILL PRODUCE HAZARDOUS BREAKING WAVES OF 6 TO 12 FEET ALONG
EXPOSED NORTHERN AND WESTERN COASTLINES OF PUERTO RICO, INCLUDING
CULEBRA AND ST. THOMAS. THEREFORE, A RIP CURRENT STATEMENT IS IN
EFFECT FOR BEACHES ALONG WESTERN TO NORTHEASTERN PR, CULEBRA, AND
THE NORTHERN U.S. VIRGIN ISLANDS THROUGH AT LEAST SATURDAY. A HIGH
SURF ADVISORY IS IN EFFECT FOR THE NORTH-FACING BEACHES OF PR
THROUGH AT LEAST 6 PM AST THIS AFTERNOON.
BEACHGOERS AND INEXPERIENCED SURFERS SHOULD FOLLOW LIFEGUARD
INSTRUCTIONS AND AVOID SWIMMING OR WALKING NEAR ROCK FORMATIONS AT
EXPOSED BEACHES. ADDITIONAL PULSES OF THE NORTHERLY SWELL ARE
EXPECTED THROUGH EARLY NEXT WEEK, KEEPING AN ELEVATED THREAT OF
LIFE-THREATENING RIP CURRENTS.
SJU WATCHES/WARNINGS/ADVISORIES
PR...HIGH RIP CURRENT RISK THROUGH SATURDAY AFTERNOON FOR PRZ001-002-
005-008-010-012.
HIGH SURF ADVISORY UNTIL 6 PM AST THIS EVENING FOR PRZ001-002-
005-008-010.
VI...HIGH RIP CURRENT RISK THROUGH SATURDAY AFTERNOON FOR VIZ001.
AM...SMALL CRAFT ADVISORY FROM NOON TODAY TO NOON AST SATURDAY FOR
AMZ711-712.
SMALL CRAFT ADVISORY FROM 6 PM THIS EVENING TO NOON AST SATURDAY
FOR AMZ741.
SHORT TERM...CAM
LONG TERM....MMC
AVIATION...CAM
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