745
FXCA62 TJSJ 231813
AFDSJU
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN JUAN PR
213 PM AST FRI OCT 23 2026
..NEW SHORT TERM, LONG TERM, AVIATION, MARINE, BEACH FORECAST
KEY MESSAGES
ISSUED AT 159 PM AST FRI OCT 23 2026
- SHOWERS AND ISOLATED THUNDERSTORMS WILL CONTINUE THROUGH THE
WEEKEND, WITH LOCALLY HEAVY RAINFALL THAT MAY LEAD TO URBAN AND
SMALL-STREAM FLOODING, RAPID RIVER RISES, AND ISOLATED FLASH
FLOODING, PARTICULARLY DURING THE AFTERNOON HOURS.
- A NORTH-NORTHWESTERLY SWELL WILL CONTINUE TO PRODUCE DANGEROUS
BREAKING WAVES AND LIFE-THREATENING RIP CURRENTS ACROSS THE
EXPOSED NORTHERN BEACHES THROUGH AT LEAST SATURDAY. ADDITIONAL
SWELL PULSES MAY KEEP SWIMMING CONDITIONS HAZARDOUS INTO EARLY
NEXT WEEK. PLEASE REFER TO THE MARINE AND BEACH FORECAST
SECTIONS BELOW FOR DETAILED INFORMATION.
- WARM AND HUMID CONDITIONS WILL PERSIST THROUGH THE NEXT SEVERAL
DAYS. HEAT IMPACTS MAY BECOME MORE PRONOUNCED EARLY NEXT WEEK,
ESPECIALLY ALONG THE COASTS, IN LOW- LYING AREAS, INTERIOR
VALLEYS, AND URBAN AREAS.
SHORT TERM(THIS EVENING THROUGH SUNDAY)
ISSUED AT 159 PM AST FRI OCT 23 2026
THE MORNING HAS BEEN MOSTLY QUIET ACROSS PUERTO RICO AND THE U.S.
VIRGIN ISLANDS, WITH SKIES RANGING FROM PARTLY CLOUDY TO CLOUDY. THE
12Z TJSJ SOUNDING INDICATED A PRECIPITABLE WATER (PWAT) VALUE OF
1.91 INCHES, WITH MEAN LOW-LEVEL WINDS FROM THE SOUTHEAST AT 11 TO
13 KT. SOME DRIER AIR INTRUSION WAS ALSO EVIDENT BETWEEN THE 850 AND
700 MB LEVELS, LIMITING SHOWER ACTIVITY. A FEW PASSING SHOWERS WERE
OBSERVED MAINLY ACROSS SOUTHEASTERN AND SOUTHERN PUERTO RICO;
HOWEVER, RADAR ESTIMATES INDICATED NO SIGNIFICANT RAINFALL
ACCUMULATIONS. WINDS WERE GENERALLY FROM THE SOUTH TO SOUTHEAST AT
10 TO 15 MPH, SLIGHTLY STRONGER THAN YESTERDAY. MAXIMUM TEMPERATURES
REACHED THE UPPER 80S TO LOWER 90S ACROSS THE LOWLANDS, URBAN AREAS,
AND COASTAL SECTIONS OF PUERTO RICO AND THE U.S. VIRGIN ISLANDS,
WHILE TEMPERATURES ACROSS THE MOUNTAINOUS INTERIOR REMAINED IN THE
70S TO LOWER 80S. HEAT INDICES EXCEEDED 105 DEGREES F IN SOME AREAS
WHERE CLOUD COVER DIMINISHED.
CLOUD COVER MOVING FROM WEST TO EAST HAS PERSISTED THROUGHOUT THE
MORNING, LIMITING DAYTIME HEATING AND POTENTIALLY INHIBITING
CONVECTIVE DEVELOPMENT, AS OBSERVED YESTERDAY. HOWEVER, SOME
CLEARING IS OCCURRING ACROSS EASTERN AND WESTERN PUERTO RICO, WHICH
COULD ALLOW FOR LOCALIZED INCREASES IN SURFACE HEATING AND SUPPORT
ADDITIONAL CONVECTIVE DEVELOPMENT THIS AFTERNOON. CURRENT MODEL
GUIDANCE INDICATES THAT SCATTERED SHOWERS EMBEDDED WITHIN THE
PREVAILING WIND FLOW WILL CONTINUE TO MOVE FROM THE SURROUNDING
EASTERN WATERS INTO EASTERN PUERTO RICO, WITH ADDITIONAL CONVECTIVE
DEVELOPMENT POSSIBLE ACROSS THE NORTHERN AND WESTERN SECTIONS OF THE
ISLAND.
OVERALL, A SURFACE HIGH OVER THE CENTRAL ATLANTIC AND A LOW
PRESSURE, ALONG WITH AN ASSOCIATED UPPER-LEVEL TROUGH TO THE
NORTHWEST, WILL MAINTAIN SOUTHEASTERLY WINDS THROUGH THE REMAINDER
OF THE WEEKEND. THE LATEST MODEL GUIDANCE SUGGESTS THAT PRECIPITABLE
WATER VALUES WILL REMAIN NEAR SEASONAL LEVELS, RANGING FROM 1.9 TO
2.1 INCHES. SOME MODELS ALSO INDICATE THAT RIDGING WILL DOMINATE IN
THE COMING DAYS, ALONG WITH AN INTRUSION OF DRIER AIR EXTENDING
THROUGH THE 850 TO 500 MB LAYER, PARTICULARLY ON SUNDAY, WHICH COULD
LIMIT DEEP CONVECTION. IN GENERAL, PASSING SHOWERS ARE EXPECTED
ACROSS EASTERN PUERTO RICO AND THE U.S. VIRGIN ISLANDS OVERNIGHT AND
DURING THE MORNING HOURS, FOLLOWED BY ADDITIONAL SCATTERED TO
NUMEROUS SHOWERS ACROSS PORTIONS OF PUERTO RICO EACH AFTERNOON.
CONSEQUENTLY, URBAN AND SMALL STREAM FLOODING, RAPID RISES IN
RIVERS, AND LOCALIZED FLASH FLOODING WILL REMAIN POSSIBLE IN AREAS
WHERE HEAVIER RAINFALL PERSISTS. THE COVERAGE AND INTENSITY OF
RAINFALL WILL DEPEND ON CLOUD COVER AND THE EXTENT OF DAYTIME
HEATING. ACROSS THE U.S. VIRGIN ISLANDS, MAINLY PASSING SHOWERS WILL
REMAIN POSSIBLE DURING THE OVERNIGHT AND MORNING HOURS.
LONG TERM(MONDAY THROUGH NEXT THURSDAY)
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
(18Z TAFS)
ISSUED AT 159 PM AST FRI OCT 23 2026
MAINLY VFR CONDS ARE EXPECTED ACROSS ALL TAF SITES THROUGH MOST OF
THE FORECAST PERIOD. HOWEVER, VCSH AND -TSRA ARE POSSIBLE AND COULD
RESULT IN INTERMITTENT/BRIEF MVFR CONDS AND MOUNTAIN OBSCURATIONS AT
TJBQ THRU 24/22Z. CONFIDENCE REMAINS LOW AS CLOD COVER COULD HELP TO
LIMIT CONVECTION. VCSH ARE EXPECTED ACROSS TJSJ AND USVI SITES
DURING THE OVERNIGHT. MAINLY S-SE WINDS UP TO 10-15 KT WITH GUST UP
TO 20 KT, AND SE WINDS AROUND 5 TO 10 KT OVERNIGHT.
MARINE
ISSUED AT 159 PM AST FRI OCT 23 2026
MODERATE TO LOCALLY FRESH EAST-TO-SOUTHEAST WINDS WILL PREVAIL
THROUGH THE WEEKEND AS THE SURFACE PRESSURE GRADIENT TIGHTENS ACROSS
REGIONAL WATERS. A NORTH-NORTHWESTERLY SWELL WILL MAINTAIN SEAS OF 5
TO 7 FEET ACROSS THE ATLANTIC WATERS AND THE MONA PASSAGE TODAY,
WITH ADDITIONAL PULSES OF NORTHERLY SWELL CONTINUING THROUGH EARLY
NEXT WEEK. SMALL CRAFT ADVISORIES REMAIN IN EFFECT FOR THE ATLANTIC
WATERS AND THE MONA PASSAGE THROUGH AT LEAST SATURDAY. ISOLATED
THUNDERSTORMS AND SCATTERED SHOWERS WILL PERSIST ACROSS THE
CARIBBEAN WATERS AND WESTERN PUERTO RICO TODAY, BRINGING THE
POTENTIAL FOR LOCALLY HIGHER SEAS AND STRONG, GUSTY WINDS.
BEACH FORECAST
ISSUED AT 159 PM AST FRI OCT 23 2026
THE ARRIVAL OF A LONG-PERIOD NORTH-NORTHWESTERLY SWELL TODAY WILL
PRODUCE HAZARDOUS BREAKING WAVES OF 6 TO 12 FEET ALONG EXPOSED
NORTHERN AND WESTERN COASTLINES OF PUERTO RICO, AS WELL AS CULEBRA
AND ST. THOMAS. CONSEQUENTLY, A HIGH SURF ADVISORY IS IN EFFECT FOR
NORTH-FACING BEACHES OF PUERTO RICO THROUGH AT LEAST 6 PM AST THIS
AFTERNOON, AND A RIP CURRENT STATEMENT REMAINS IN EFFECT FOR BEACHES
ALONG WESTERN-TO-NORTHEASTERN PUERTO RICO, CULEBRA, AND THE NORTHERN
U.S. VIRGIN ISLANDS THROUGH AT LEAST SATURDAY.
BEACHGOERS AND INEXPERIENCED SWIMMERS SHOULD FOLLOW LIFEGUARD
INSTRUCTIONS AND AVOID SWIMMING OR WALKING NEAR ROCK FORMATIONS ON
EXPOSED BEACHES. ADDITIONAL PULSES OF THE NORTHERLY SWELL ARE
EXPECTED THROUGH EARLY NEXT WEEK, MAINTAINING AN ELEVATED RISK 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 UNTIL NOON AST SATURDAY FOR AMZ711-712.
SMALL CRAFT ADVISORY FROM 6 PM THIS EVENING TO NOON AST SATURDAY
FOR AMZ741.
SHORT TERM/AVIATION...YZR
LONG TERM...MMC
MARINE/BEACH FORECAST...GRS
CLICK HERE TO GO TO PREVIOUS BULLETINS.
Main Text Page