347
FXCA62 TJSJ 280820
AFDSJU
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN JUAN PR
420 AM AST SUN DEC 28 2025
...NEW SHORT TERM, LONG TERM, AVIATION, MARINE, BEACH FORECAST, FIRE WEATHER...
KEY MESSAGES
ISSUED AT 420 AM AST SUN DEC 28 2025
* SMALLER PULSES OF LONG-PERIOD NORTHERLY SWELL WILL CONTINUE TO
SPREAD ACROSS THE REGION THROUGH MIDWEEK, MAINTAINING A HIGH
POTENTIAL FOR LIFE-THREATENING RIP CURRENTS ALONG ATLANTIC- AND
NORTH-FACING BEACHES OF PUERTO RICO, INCLUDING CULEBRA, AND
ACROSS THE NORTHERN U.S. VIRGIN ISLANDS. THIS RISK REMAINS
LIKELY THROUGH AT LEAST MONDAY AND MAY EXTEND INTO MIDWEEK.
* CONDITIONS WILL REMAIN MOSTLY QUIET THROUGH MIDWEEK, WITH BRIEF
PASSING SHOWERS AT TIMES AND LITTLE TO NO THUNDERSTORM ACTIVITY
EXPECTED. A WETTER TRANSITION IS LIKELY LATE IN THE WEEK AS AN
UPPER-LEVEL DISTURBANCE AND A WEAK SURFACE TROUGH APPROACH,
THOUGH IMPACTS ARE EXPECTED TO BE LOCALIZED.
* WEATHER CONDITIONS WILL REMAIN GENERALLY STABLE WITH PASSING
SHOWERS AT TIMES. SHOWER AND THUNDERSTORM ACTIVITY MAY INCREASE
TOWARD THE END OF THE WEEK.
* NEW YEAR’S EVE: UNSETTLED BUT MANAGEABLE CONDITIONS WITH BREEZY
TRADE WINDS, OCCASIONAL PASSING SHOWERS, COOLER TEMPERATURES
EARLY, AND A CONTINUED HIGH RISK OF LIFE- THREATENING RIP
CURRENTS ALONG NORTH- AND ATLANTIC-FACING BEACHES.
SHORT TERM(TODAY THROUGH TUESDAY)
ISSUED AT 420 AM AST SUN DEC 28 2025
SKIES WERE CLEAR DURING THE NIGHT HOURS, ALLOWING FOR TEMPERATURES
TO COOL DOWN ONCE AGAIN TO THE 50S IN THE MOUNTAINS, AND THE 60S IN
LOWER ELEVATIONS. A FEW SHOWERS MANAGED TO DEVELOP OVER THE LOCAL
WATERS, BUT NONE REACHED LAND AREAS.
A POLAR TROUGH MAINTAINS THE PRESSURE GRADIENT WEAK, WITH A STEERING
FLOW OF ONLY 3-7 KTS. AT THE MID AND UPPER LEVELS, RELATIVE
HUMIDITIES ARE VERY LOW, AND A TRADE WIND CAP WILL STAY IN PLACE
AROUND 800 MB. AT THE LOW LEVELS, MOISTURE WILL REMAIN NEAR TWO
STANDARD DEVIATIONS BELOW NORMAL, WITH VALUES OF 0.6 TO 0.8 INCHES.
SOME SMALL PATCHES OF MOISTURE MAY FILTER IN AT TIMES, BUT STILL,
THE PROBABILITY OF RAIN FOR THE PERIOD IS NOT GREATER THAN 30%, AND
FOCUSED IN PORTIONS OF EASTERN PUERTO RICO AND THE VIRGIN ISLANDS.
TEMPERATURES WILL REMAIN COOLER THAN NORMAL, ESPECIALLY TODAY AND
TOMORROW. LOWS WILL BE IN THE 50S AND LOW 60S FOR THE MOUNTAINS.
HIGHS WILL BE IN THE LOW 70S FOR THE HIGHER MOUNTAINS AND IN THE LOW
AND MID 80S FOR COASTAL AREAS.
LONG TERM(WEDNESDAY THROUGH SUNDAY)
ISSUED AT 420 AM AST SUN DEC 28 2025
EXPECT PERIODS OF UNSETTLED WEATHER WITH BRIEF PERIODS OF HEAVY
RAIN AND OCCASIONAL LIGHTNING. BREEZY TRADE WINDS WILL BRING
FREQUENT PASSING SHOWERS, ESPECIALLY FROM WEDNESDAY INTO EARLY
THURSDAY, WITH COOLER-THAN- NORMAL TEMPERATURES AT THE START OF
THE PERIOD. WEATHER CONDITIONS BECOME MORE ACTIVE FRIDAY INTO
SATURDAY AS A SHORT-WAVE TROUGH AND SURFACE-INDUCED TROUGH MOVES
THROUGH THE REGION, THEN GRADUALLY IMPROVE LATE IN THE WEEKEND.
TEMPERATURES ARE EXPECTED TO SLOWLY WARM, WITH WARMER-THAN-NORMAL
CONDITIONS POSSIBLE BY THE WEEKEND.
THE MAIN WEATHER CONCERNS WILL BE RAINFALL, LIGHTNING, AND GUSTY
WINDS. THE HIGHEST RISK PERIOD IS EXPECTED FROM FRIDAY MORNING INTO
FRIDAY NIGHT, WHEN SCATTERED TO LOCALLY NUMEROUS SHOWERS AND
ISOLATED THUNDERSTORMS ARE LIKELY. LIGHTNING AND BRIEF STRONG
WIND GUSTS HAZARD RISKS WILL BE MORE LIKELY DURING THIS TIME, AND
TRADE WINDS WILL BE STRONGEST AROUND FRIDAY EVENING. FROM
SATURDAY INTO SUNDAY, SHOWERS WILL STILL OCCUR, BUT THUNDERSTORM
ACTIVITY SHOULD GRADUALLY DECREASE. A LOWER CONFIDENCE INCREASE
IN THUNDERSTORM POTENTIAL MAY RETURN LATE SUNDAY NIGHT, DEPENDING
ON HOW CONDITIONS EVOLVE WITH THE PROXIMITY OF THE NEXT SHORT-
WAVE TROUGH.
AVIATION
(06Z TAFS)
ISSUED AT 420 AM AST SUN DEC 28 2025
VFR CONDITIONS EXPECTED FOR TODAY. WINDS WILL BE MOSTLY LIGHT. FROM
14-22Z, WINDS WILL BE FROM THE NNE AT 7-10 KTS, AND AFTER 22Z, WINDS
WILL BE AT 3-5 KTS. THERE IS A LOW CHANCE OF SHRA IN THE VICINITY OF
TJPS, BUT IMPACTS TO OPERATIONS ARE EXPECTED TO BE MINIMAL TO
NONE.
MARINE
ISSUED AT 420 AM AST SUN DEC 28 2025
A SURFACE HIGH OVER THE WESTERN ATLANTIC WILL MAINTAIN LIGHT TO
MODERATE EAST TO NORTHEAST WINDS ACROSS THE CARIBBEAN WATERS,
WHILE WINDS ACROSS THE ATLANTIC WATERS REMAIN LIGHT AND VARIABLE
THROUGH MIDWEEK, BECOMING MORE UNIFORM ACROSS THE REGION TOWARD
THE END OF THE WORKWEEK. SMALLER PULSES OF NORTHERLY SWELL WILL
CONTINUE THROUGH MIDWEEK; WHILE HAZARDOUS SEAS ARE NOT EXPECTED,
SMALL CRAFT ARE ADVISED TO EXERCISE CAUTION, ESPECIALLY ACROSS THE
ATLANTIC WATERS AND PASSAGES. SHOWER AND THUNDERSTORM ACTIVITY
INCREASES MID TO LATE WEEK, WITH LOCALLY HAZARDOUS MARINE
CONDITIONS POSSIBLE.
BEACH FORECAST
ISSUED AT 420 AM AST SUN DEC 28 2025
PULSES OF NORTHERLY SWELL WILL CONTINUE TO MOVE THROUGH THE
REGION, SUPPORTING A CONTINUED HIGH LIKELIHOOD OF LIFE-
THREATENING RIP CURRENTS ALONG EXPOSED SHORELINES. AS A RESULT, A
HIGH RIP CURRENT RISK REMAINS IN EFFECT THROUGH MONDAY FOR NORTH-
AND ATLANTIC-FACING BEACHES OF PUERTO RICO, INCLUDING CULEBRA, AS
WELL AS ST. THOMAS AND ST. JOHN. SIMILAR RIP CURRENT CONDITIONS
ARE EXPECTED TO PERSIST INTO MIDWEEK, WITH A GRADUAL IMPROVEMENT
LATE IN THE WEEK.
BREAKING WAVES ARE EXPECTED TO REMAIN AROUND 6 FEET AT NORTH-
FACING BEACHES. RIP CURRENTS MAY BE STRONG AND DIFFICULT TO
ESCAPE, ESPECIALLY AT UNGUARDED BEACHES. BEACHGOERS ARE URGED TO
AVOID ENTERING THE WATER AT EXPOSED BEACHES AND TO FOLLOW ALL
LOCAL BEACH FLAGS AND SAFETY GUIDANCE.
FIRE WEATHER
ISSUED AT 420 AM AST SUN DEC 28 2025
DRYING CONDITIONS CONTINUE, ESPECIALLY ACROSS SOUTHERN PUERTO
RICO. NO RAINFALL IS EXPECTED TODAY, AND NO EFFECTIVE RAIN-MAKERS
ARE ANTICIPATED THROUGH AT LEAST MID TO LATE WEEK, ALLOWING FUELS
TO CONTINUE DRYING. FIRE DANGER REMAINS LOW TODAY, AND NO ACTIVE
FIRES ARE REPORTED OR IDENTIFIED ACROSS THE ISLANDS. KBDI VALUES
CONTINUE TO TREND UPWARD, WITH RECENT READINGS NEAR 545 AT CABO
ROJO AND 509 AT CAMP SANTIAGO, INDICATING INCREASING FUEL DRYNESS
AND APPROACHING FIRE WEATHER HEADLINE THRESHOLDS (AROUND 550).
PERIODS OF LOW RELATIVE HUMIDITY, COMBINED WITH MODERATE BREEZES
AND OCCASIONAL STRONGER TRADE-WIND GUSTS, MAY BRIEFLY ENHANCE FIRE
SPREAD POTENTIAL. OVERALL FIRE DANGER REMAINS LOW, BUT CONTINUED
DRYING WARRANTS CLOSE MONITORING, PARTICULARLY ACROSS SOUTHERN
PUERTO RICO.
SJU WATCHES/WARNINGS/ADVISORIES
PR...HIGH RIP CURRENT RISK THROUGH LATE MONDAY NIGHT FOR PRZ001-002-
005-008-010-012.
VI...HIGH RIP CURRENT RISK THROUGH LATE MONDAY NIGHT FOR VIZ001.
AM...NONE.
SHORT TERM/AVIATION...ERG
LONG TERM/PUBLIC....ICP
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