353
FXCA62 TJSJ 290833 CCA
AFDSJU
AREA FORECAST DISCUSSION...CORRECTED
NATIONAL WEATHER SERVICE SAN JUAN PR
433 AM AST WED OCT 29 2025
..NEW SHORT TERM, LONG TERM, AVIATION, MARINE, BEACH FORECAST
KEY MESSAGES
ISSUED AT 349 AM AST WED OCT 29 2025
* THE US VIRGIN ISLANDS AND PUERTO RICO CAN EXPECT AN ELEVATED
RISK OF EXCESSIVE HEAT ACROSS THE COASTAL AND URBAN AREAS TODAY
AND TOMORROW. THUS, A HEAT ADVISORY IS IN EFFECT FOR TODAY.
* THE NORTH-FACING BEACHES IN PR, CULEBRA, AND ST CROIX WILL HAVE A
HIGH RISK OF RIP CURRENTS TODAY.
* THE GREATEST CHANCE OF RAINFALL ARRIVES SATURDAY, AS A TROPICAL
WAVE MOVES THROUGH, INCREASING THE POTENTIAL OF MODERATE TO
HEAVY SHOWERS AND ISOLATED THUNDERSTORMS FOR THE REGION.
SHORT TERM
(TODAY THROUGH FRIDAY)
ISSUED AT 349 AM AST WED OCT 29 2025
RELATIVELY CALM CONDITIONS PREVAILED OVERNIGHT ACROSS PUERTO RICO
AND THE US VIRGIN ISLANDS, OBSERVED UNDER CLEAR TO PARTLY CLOUDY
SKIES. EARLY THIS MORNING, DOPPLER RADAR DETECTED A FEW PASSING
SHOWERS OVER PORTIONS OF EASTERN PUERTO RICO AND CULEBRA; HOWEVER,
RAINFALL AMOUNTS WERE MINIMAL. OVERNIGHT LOW TEMPERATURES RANGED
FROM THE MID TO UPPER 70S ALONG COASTAL AND URBAN AREAS, DROPPING
TO THE UPPER 60S AND LOW 70S ALONG THE CENTRAL MOUNTAIN RANGE.
WINDS WERE GENERALLY LIGHT FROM THE SOUTHEAST, BETWEEN 5 AND 10
MPH.
TODAY’S WEATHER WILL CONTINUE TO BE INFLUENCED BY THE DISTANT
HURRICANE MELISSA, LOCATED WELL TO THE WEST-NORTHWEST (OVER CUBA),
AND A BROAD SURFACE HIGH-PRESSURE SYSTEM SITUATED OVER THE
CENTRAL ATLANTIC. THE PRESSURE GRADIENT BETWEEN THESE TWO FEATURES
WILL MAINTAIN A LIGHT TO MODERATE EAST-SOUTHEASTERLY WIND FLOW,
WHICH WILL CONTINUE TO BRING PATCHES OF LOW-LEVEL MOISTURE INTO
THE AREA. DESPITE THIS MOISTURE, THE PRESENCE OF THE HIGH-PRESSURE
SYSTEM IS EXPECTED TO LIMIT SHOWER ACTIVITY ACROSS THE REGION.
THE MAIN FOCUS FOR RAIN WILL BE IN THE AFTERNOON, WITH LOCALIZED
CONVECTIVE ACTIVITY AND SHOWERS POSSIBLE OVER PORTIONS OF CENTRAL
PUERTO RICO DUE TO THE COMBINATION OF DAYTIME HEATING AND LOCAL
OROGRAPHIC EFFECTS.
LOOKING AHEAD, THE HIGH-PRESSURE SYSTEM IS FORECAST TO STRENGTHEN
AND BECOME THE DOMINANT FEATURE FROM THURSDAY INTO FRIDAY. THIS
WILL CAUSE THE WINDS TO SHIFT, BECOMING SOUTHERLY ON THURSDAY AND
THEN SOUTH-SOUTHEASTERLY LATER IN THE DAY. UNDER THIS PATTERN,
TRADE-WIND SHOWERS ARE LIKELY ACROSS THE US VIRGIN ISLANDS DURING
THE MORNING HOURS, WHILE AFTERNOON CONVECTIVE ACTIVITY WILL BE
EXPECTED ACROSS THE CENTRAL AND NORTHERN PORTIONS OF PUERTO RICO.
THIS ACTIVITY WILL RESULT IN A LIMITED FLOODING RISK.
ELEVATED HEAT CONDITIONS ARE EXPECTED THROUGHOUT THE FORECAST
PERIOD, DRIVEN BY ABOVE-NORMAL TEMPERATURES AT THE 925 MB LEVEL.
MAXIMUM TEMPERATURES ALONG THE COASTAL AND URBAN AREAS ARE
FORECAST TO RANGE FROM THE UPPER 80S TO LOW 90S, WHEREAS MOUNTAIN
AREAS WILL SEE HIGHS IN THE UPPER 70S TO LOW 80S. HEAT INDICES ARE
EXPECTED TO BE ELEVATED, AND HEAT ADVISORIES MAY BECOME NECESSARY
FOR COASTAL AND URBAN ZONES. RESIDENTS AND VISITORS SHOULD PLAN
TO STAY HYDRATED AND PROTECT THEMSELVES FROM PROLONGED SUN
EXPOSURE.
LONG TERM
(SATURDAY THROUGH WEDNESDAY)
ISSUED AT 349 AM AST WED OCT 29 2025
A TROPICAL WAVE IS LIKELY TO MOVE ACROSS THE LESSER ANTILLES LATE
FRIDAY NIGHT INTO EARLY SATURDAY MORNING, WITH ITS LEADING EDGE
EXPECTED TO REACH THE US VIRGIN ISLANDS AND PUERTO RICO SOMETIME
BETWEEN SATURDAY MORNING AND AFTERNOON. CURRENT MODEL GUIDANCE
SUGGESTS AN INCREASING PROBABILITY OF WIDESPREAD SHOWER ACTIVITY,
WITH A MODERATE TO HIGH CHANCE (60-80%) OF THUNDERSTORMS
DEVELOPING IN THE AFTERNOON.
SHOWERS ARE EXPECTED TO GRADUALLY INCREASE THROUGH THE DAY, MOST
LIKELY BEGINNING OVER REGIONAL WATERS AND WINDWARD AREAS, THEN
SPREADING INLAND BY MID-MORNING INTO THE AFTERNOON. LOCAL EFFECTS,
DIURNAL HEATING, AND SEA-BREEZE CONVERGENCE COULD ENHANCE
RAINFALL INTENSITY, RAISING THE POTENTIAL (40-60%) FOR PERIODS OF
HEAVY RAIN, FREQUENT LIGHTNING, AND BRIEF GUSTY WINDS,
PARTICULARLY ACROSS PUERTO RICO. THE ACTIVITY SHOULD MOVE MORE
QUICKLY ACROSS THE US VIRGIN ISLANDS, LIMITING RAINFALL DURATION
THERE.
TROPICAL MOISTURE ASSOCIATED WITH THIS WAVE IS EXPECTED TO
DIMINISH GRADUALLY LATE SATURDAY NIGHT INTO EARLY SUNDAY MORNING.
AS IT DEPARTS, THE LOCAL AREA WILL LIKELY TRANSITION TO A MORE
SEASONAL PATTERN, CHARACTERIZED BY A MIX OF MOSTLY CLEAR SKIES AND
OCCASIONAL PASSING SHOWERS (30-40% CHANCE).
FROM SUNDAY ONWARD, ISOLATED TO SCATTERED AFTERNOON CONVECTION
REMAINS POSSIBLE EACH DAY, DRIVEN PRIMARILY BY LOCAL TOPOGRAPHY,
DIURNAL HEATING, AND SEA-BREEZE INTERACTIONS. THIS GENERAL PATTERN
WILL LIKELY DOMINATE THROUGH THE FIRST HALF OF NEXT WEEK, AS A
BUILDING HIGH-PRESSURE SYSTEM OVER THE REGION REDUCES ATMOSPHERIC
INSTABILITY AND LOWERS THE OVERALL PROBABILITY OF WIDESPREAD
THUNDERSTORM ACTIVITY.
AVIATION
(06Z TAFS)
ISSUED AT 349 AM AST WED OCT 29 2025
MAINLY VFR CONDS EXPECTED ACROSS AL TERMINALS DURING THE NEXT 24 HRS.
OCCASIONAL TRADE-WIND SHRA WILL AFFECT TIST/TISX RESULTING IN VCSH
AFT 29/13Z. AFTERNOON CONVECTIVE ACTIVITY MAY RESULT IN SHRA/TSRA,
AND BRIEF VIS/CIGS REDUCTIONS AT TIMES PARTICULARLY NEAR TJBQ/TJPS.
LGT/VRB WINDS THRU 29/13Z, THEN BECOMING FROM THE ESE AT 10–15 KT
WITH SEA BREEZE VARIATIONS AND HIGHER GUSTS.
MARINE
ISSUED AT 349 AM AST WED OCT 29 2025
THE REGION WILL CONTINUE UNDER A SOUTHEASTERLY WIND FLOW AS MELISSA
MOVES FROM THE WESTERN CARIBBEAN INTO THE WESTERN ATLANTIC THROUGH
AT LEAST THURSDAY. THEN, A FRONTAL BOUNDARY WILL APPROACH THE REGION
FROM THE WEST, INTERACTING WITH A SURFACE HIGH PRESSURE ANCHORED
ACROSS THE CENTRAL ATLANTIC AROUND FRIDAY, PROMOTING THE RETURN OF A
MODERATE TO LOCALLY FRESH EASTERLY WIND FLOW. A TROPICAL WAVE WILL
MOVE NEAR THE NORTHEAST CARIBBEAN AND THE LOCAL WATERS AROUND
SATURDAY, INCREASING THE POTENTIAL FOR SHOWERS AND THUNDERSTORMS.
BEACH FORECAST
ISSUED AT 349 AM AST WED OCT 29 2025
A LONG PERIOD NORTHEASTERLY SWELL WITH PERIODS BETWEEN 12 AND 16
SECONDS IS REACHING SAN JUAN BUOY. THIS SWELL WILL RESULT IN A
HIGH RISK OF RIP CURRENTS ALONG PR, CULEBRA AND ST CROIX'S NORTH
AND EAST-FACING BEACHES THROUGH THIS EVENING. THUS, A HIGH RISK OF
RIP CURRENTS IS IN EFFECT FOR THESE AREAS.
SJU WATCHES/WARNINGS/ADVISORIES
PR...HIGH RIP CURRENT RISK THROUGH THIS AFTERNOON FOR PRZ001-002-005-
008-012.
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.
HIGH RIP CURRENT RISK THROUGH THIS AFTERNOON FOR VIZ002.
AM...NONE.
OVERNIGHT CREW...CAM/GRS
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