435
FXCA62 TJSJ 240817
AFDSJU
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN JUAN PR
417 AM AST MON NOV 24 2025
..NEW SHORT TERM, LONG TERM, AVIATION, MARINE, BEACH FORECAST
KEY MESSAGES
ISSUED AT 417 AM AST MON NOV 24 2025
* PLEASANT TEMPERATURES, WITH A MIX OF SUNSHINE AND CLOUDS, WILL
PREVAIL ACROSS THE USVI AND PR THROUGHOUT THE WEEK.
* BREEZY TRADE WINDS WILL PREVAIL FROM TUESDAY ONWARD, BECOMING
WINDY BY THE UPCOMING WEEKEND.
* OCCASIONAL PERIODS OF SHOWERY WEATHER WILL AFFECT MAINLY THE
WINDWARD LOCATIONS OF PR AND THE USVI AT TIMES.
* LOW RISK OF RIP CURRENTS TODAY, INCREASING TO MODERATE ON
TUESDAY EVENING AND WEDNESDAY.
SHORT TERM(TODAY THROUGH WEDNESDAY)
ISSUED AT 417 AM AST MON NOV 24 2025
TRADE-WIND SHOWERS MOVED ACROSS PORTIONS OF NORTHWEST, EAST, AND
SOUTHEAST PUERTO RICO, AS WELL AS CULEBRA AND THE U.S. VIRGIN
ISLANDS, OVERNIGHT. WESTERN PUERTO RICO REMAINED MOSTLY CLOUDY
FROM LATE SUNDAY NIGHT INTO EARLY MONDAY MORNING. DURING THE EARLY
MORNING HOURS TODAY, SKIES GRADUALLY CLEARED, LEAVING MOSTLY
CLEAR SKIES CONDITIONS WITH A FEW TRADE-WIND CLOUDS. HOWEVER,
PATCHES WITH CLOUDS MOVED QUICKLY OVER THE ST THOMAS, ST. JOHN AND
ST CROIX. THE CLEAR SKIES ALLOWED OVERNIGHT COOLING TO BRING
TEMPERATURES INTO THE LOW–MID 70S ACROSS COASTAL AREAS AND INTO
THE LOW 60S, OR SLIGHTLY LOWER, IN THE MOUNTAINS AND VALLEYS.
WINDS WERE MAINLY FROM THE NORTHEAST WITH LAND BREEZE VARIATIONS.
A ZONAL FLOW ALOFT IS EXPECTED TO PREVAIL ACROSS THE ISLANDS TODAY.
AN UPPER-LEVEL SHORTWAVE TROUGH WILL MOVE ACROSS THE NORTHEASTERN
CARIBBEAN BETWEEN LATE TONIGHT AND TUESDAY, WHILE THE MID-LEVEL
RIDGE SHIFTS WESTWARD TOWARD THE CUBA/BAHAMAS REGION. IF THIS
PATTERN MATERIALIZES, THE TRADE-WIND INVERSION WILL LIKELY WEAKEN,
ALLOWING LOW-LEVEL MOISTURE TO RISE TO AROUND 700 MB OR HIGHER
BETWEEN TUESDAY MORNING AND AFTERNOON.
CONFIDENCE IS MODERATE/HIGH THAT THE RIDGE PATTERN WILL WEAKEN
FURTHER ON WEDNESDAY AS A POLAR TROUGH MOVES NORTH OF THE REGION,
SUPPORTING A JET STREAK OF 57–70 MPH OVER PORTIONS OF THE LOCAL AREA
FROM EARLY WEDNESDAY MORNING INTO THE AFTERNOON.
AT THE SURFACE, HIGH PRESSURE EXITING THE U.S. EASTERN SEABOARD THIS
AFTERNOON WILL CONTINUE PUSHING A FRONTAL BOUNDARY FROM THE WESTERN
ATLANTIC INTO THE CENTRAL ATLANTIC BY TUESDAY. AS THIS OCCURS, THE
LOCAL PRESSURE GRADIENT WILL LIKELY TIGHTEN, PROMOTING AN INCREASE
IN WINDS AS EARLY AS TUESDAY AFTERNOON AND MOST LIKELY BY WEDNESDAY.
TODAY, REMNANTS OF AN OLD BOUNDARY WILL MOVE ACROSS THE AREA,
BRINGING A MODERATE (30–50%) TO HIGH (60%) CHANCE OF PASSING SHOWERS
ACROSS THE WINDWARD AREAS OF PUERTO RICO AND THE U.S. VIRGIN
ISLANDS. THESE SHOWERS MAY SPREAD INTO THE INTERIOR AND SOUTHWEST
PUERTO RICO BY LATE MORNING INTO THE AFTERNOON, MAINTAINING A
MODERATE/HIGH CHANCE (30–60%) OF RAINFALL. CONDITIONS SHOULD DRY OUT
BY THIS EVENING, BUT OCCASIONAL PATCHES OF MOISTURE WILL SUSTAIN A
MODERATE CHANCE (30–50%) OF SHOWERS ACROSS THE U.S. VIRGIN ISLANDS
AND PUERTO RICO EASTERN THIRD.
AN ADVECTIVE TRADE-WIND PATTERN WILL DOMINATE OVER THE SHORT TERM.
THIS SUPPORTS A SLIGHT (10–20%) TO MODERATE (30-50%) CHANCE OF
SHOWERS ALONG THE USVI AND PR'S WINDWARD AREAS, AND A
SLIGHT/MODERATE CHANCE (20–50%) OF AFTERNOON SHOWERS OVER THE
INTERIOR AND SOUTHWEST PUERTO RICO EACH DAY.
TEMPERATURES WILL CONTINUE A COOLING TREND THROUGH MIDWEEK, WITH
MODEL GUIDANCE SHOWING 925-MB TEMPERATURES NEAR THE 25TH PERCENTILE
FOR NOVEMBER CLIMATOLOGY FROM TODAY THROUGH THE MIDDLE OF THE WEEK
AND INTO THE LONG TERM.
LONG TERM(THURSDAY THROUGH MONDAY)
ISSUED AT 417 AM AST MON NOV 24 2025
THE LONG-TERM PERIOD WILL PRIMARILY FEATURE BREEZY TO LOCALLY
WINDY CONDITIONS, ALONG WITH PATCHES OF MOISTURE EMBEDDED WITHIN
THE TRADE WINDS. THESE FACTORS WILL BRING A MODERATE LIKELIHOOD OF
OCCASIONAL SHOWERS. PWAT GUIDANCE INDICATES VALUES REMAINING NEAR
TO SLIGHTLY BELOW NORMAL FOR NOVEMBER BASED ON CLIMATOLOGICAL
DATA.
BY THURSDAY INTO FRIDAY, THE JET STREAK WILL SHIFT EASTWARD AND
AWAY FROM THE AREA, WHILE THE RIDGING PATTERN WEAKENS AS A POLAR
TROUGH MOVES ACROSS THE CENTRAL ATLANTIC.
FROM SATURDAY INTO EARLY NEXT WEEK, A HIGH-PRESSURE SYSTEM
BUILDING OVER THE WESTERN ATLANTIC WILL FURTHER TIGHTEN THE
PRESSURE GRADIENT, RESULTING IN STRONGER BREEZES. THE BREEZIEST
DAYS APPEAR TO BE SUNDAY AND MONDAY. A GRADUAL INCREASE IN PWAT
VALUES MAY ENHANCE RAIN CHANCES, ALTHOUGH FLOODING CONCERNS ARE
NOT ANTICIPATED.
MODEL GUIDANCE SUGGESTS THAT 925-MB TEMPERATURES WILL REMAIN
WITHIN THE NORMAL TO BELOW-NORMAL RANGE FOR THIS TIME OF YEAR,
SUPPORTING THE ONGOING TRANSITION TOWARD MORE COMFORTABLE
TEMPERATURES.
AVIATION
(06Z TAFS)
ISSUED AT 417 AM AST MON NOV 24 2025
TRADE WIND -SHRA/SHRA WILL OCCASIONALLY MOVE ACROSS LOCAL TAFS
(JSJ/IST/ISX) THROUGHOUT THE FORECAST PERIOD. THIS SHRA/-SHRA WILL
REACH JPS BETWEEN 24/15-22Z, WHEN MOUNTAIN OBSC WILL FORM ALONG
THE CORDILLERA CENTRAL. ALTHOUGH WE EXPECT VFR CONDS, SOME OF
THESE SHRA WILL RESULT IN BRIEF MVFR CONDS BY LIMITING VIS OR
INCREASING CEILINGS BTWN FL022-FL040. WINDS WILL PREVAIL CALM TO
LIGHT AND VRB THRU 24/13Z, THEN WILL CONTINUE FROM THE ENE AT
10-15 KT WITH HIGHER GUSTS AND SEA BREEZE VARIATIONS.
MARINE
ISSUED AT 417 AM AST MON NOV 24 2025
HIGH PRESSURE BUILDING OVER THE WESTERN ATLANTIC, COMBINED WITH A
SURFACE TROUGH ACROSS THE CENTRAL ATLANTIC, WILL MAINTAIN GENTLE
TO MODERATE EAST TO NORTHEAST WINDS TODAY. AS THE HIGH PRESSURE
SYSTEM MOVES INTO THE CENTRAL ATLANTIC THROUGH MID-WEEK, THE
PRESSURE GRADIENT WILL TIGHTEN, PROMOTING MODERATE TO LOCALLY
FRESH TRADE WINDS FROM TONIGHT OR TUESDAY ONWARD. AS A RESULT,
EXPECT CONFUSED SEAS CAUSED BY A MIX OF LOCALLY CHOPPY CONDITIONS
AND A BRIEF LONG-PERIOD NORTHEASTERLY SWELL ARRIVING BETWEEN
TUESDAY AND WEDNESDAY. SMALL CRAFT OPERATORS WILL LIKELY NEED TO
EXERCISE CAUTION, PARTICULARLY ACROSS THE OFFSHORE WATERS AND
LOCAL CARIBBEAN PASSAGES FOR MOST OF THE FORECAST PERIOD.
BEACH FORECAST
ISSUED AT 417 AM AST MON NOV 24 2025
THE RISK OF RIP CURRENTS REMAINS LOW TODAY ALONG ALL LOCAL
BEACHES IN PUERTO RICO AND THE U.S. VIRGIN ISLANDS. REMEMBER THAT
EVEN WITH A LOW RISK, LIFE-THREATENING RIP CURRENTS CAN STILL
OCCUR NEAR GROINS, JETTIES, REEFS, AND PIERS.
CONDITIONS ARE EXPECTED TO CHANGE ON TUESDAY EVENING, WITH THE
RISK INCREASING TO MODERATE THROUGH WEDNESDAY DUE TO STRENGTHENING
WINDS AND A BRIEF NORTHEASTERLY SWELL. BY THURSDAY AND FRIDAY,
THE RISK IS EXPECTED TO BECOME HIGH ALONG THE NORTH-FACING
BEACHES OF THE ISLANDS. ALWAYS CHECK THE BEACH FORECAST BEFORE
HEADING OUT, AND AVOID SWIMMING AT BEACHES WITH A HIGH RISK. FOR
LOCATION-SPECIFIC INFORMATION, VISIT WEATHER.GOV/BEACH/SJU.
SJU WATCHES/WARNINGS/ADVISORIES
PR...NONE.
VI...NONE.
AM...NONE.
SHORT TERM/AVIATION/KEY MESSAGES...CAM
LONG TERM/MARINE/BEACH...YZR
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