257
FXCA62 TJSJ 261904
AFDSJU
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN JUAN PR
304 PM AST SUN OCT 26 2025
..NEW SHORT TERM, AVIATION, MARINE, BEACH FORECAST
KEY MESSAGES
* OVERNIGHT AND MORNING SHOWERS ACROSS WINDWARD AREAS AND
ADVECTIVE SHOWERS ARE EXPECTED OVER THE COMING DAYS, MAINTAIN
THE FLOOD POTENTIAL FROM LIMITED TO ELEVATED ACROSS PUERTO RICO
SOUTHERN, EASTERN AND WESTERN PUERTO RICO.
* ACROSS THE U.S. VIRGIN ISLANDS, ISOLATED TO SCATTERED SHOWERS
FROM TIME TO TIME, PARTICULARLY OVERNIGHT INTO THE MORNING
HOURS.
* A MODERATE RISK OF RIP CURRENTS WILL CONTINUE FOR MOST BEACHES
OF PUERTO RICO AND THE U.S. VIRGIN ISLANDS THROUGH THE REMAINDER
OF THE WEEKEND AND EARLY NEXT WEEK, WHILE A HIGH RISK WILL BE
POSSIBLE ACROSS NORTH-EXPOSED BEACHES AROUND MID WEEK.
SHORT TERM
(THIS EVENING THROUGH TUESDAY)
ISSUED AT 257 PM AST SUN OCT 26 2025
DURING THE MORNING HOURS, RADAR AND SATELLITE IMAGERY SHOWED
CLOUD COVER ACROSS THE ISLANDS, WITH SHOWERS MOVING THROUGH THE
LOCAL WATERS. UNDER A SOUTHEASTERLY WIND PATTERN, SOME SHOWERS
WERE CARRIED OVER THE USVI AND THE WINDWARD AREAS OF PUERTO RICO.
AFTER 12 PM, SHOWERS INCREASED IN FREQUENCY AND AREAL COVERAGE,
SPREADING INTO THE METROPOLITAN AREA, AS WELL AS THE INTERIOR AND
NORTHWEST QUADRANT OF PUERTO RICO. BASED ON DOPPLER RADAR
ESTIMATES, RAINFALL VALUES SO FAR TODAY (UNTIL 12:50 PM AST)
GENERALLY RANGE FROM 0.5 TO 1 INCH, WITH MAXIMUM AMOUNTS REACHING
UP TO 2 INCHES IN THE EL YUNQUE NATIONAL FOREST AREA AND AGUADA
MUNICIPALITY. AS A RESULT, MULTIPLE FLOOD ADVISORIES WERE ISSUED.
A STRONG THUNDERSTORM ALSO DEVELOP NEAR BAYAMON AND AN SPECIAL
WEATHER STATEMENT WAS ISSUED DUE TO WIND GUSTS, TORRENTIAL
RAINFALL AND LIGHTNING. DAYTIME MAXIMUM TEMPERATURES HAVE WARMED
SLIGHTLY TODAY, WITH TEMPERATURES IN THE MID TO UPPER 80S ACROSS
MOST COASTAL AND URBAN AREAS OF PUERTO RICO AND THE U.S. VIRGIN
ISLANDS. WINDS HAVE PRIMARILY BEEN FROM THE SOUTHEAST AT AROUND 10
TO 15 MPH, WITH HIGHER GUSTS AND TYPICAL SEA BREEZE VARIATIONS.
ACCORDING TO HIGH-RESOLUTION MODELS, TONIGHT AND EARLY MONDAY
MORNING, SHOWERS WILL BE CONCENTRATED ACROSS THE LOCAL WATERS,
OCCASIONALLY AFFECTING THE USVI AND PARTICULARLY IMPACTING THE
WINDWARD AREAS OF PUERTO RICO (EASTERN, SOUTHEASTERN, AND
SOUTHERN PR, VIEQUES, AND CULEBRA). THIS PATTERN WILL MAINTAIN THE
POTENTIAL FOR FLOODING IN URBAN AREAS, ON ROADS, SMALL STREAMS,
AND WASHES.
THE REMAINDER OF THE SHORT-TERM FORECAST WILL CONTINUE TO FEATURE
ADVECTIVE SHOWERS AND AFTERNOON THUNDERSTORMS DUE TO LOCAL EFFECTS.
OVERALL, PRECIPITABLE WATER CONTENT IS EXPECTED TO REMAIN AT OR
ABOVE 2.00 INCHES FOR THE REST OF THE PERIOD, WHICH IS CONSIDERED
A HIGH-END AVERAGE TO SLIGHTLY ABOVE NORMAL BASED ON CLIMATOLOGICAL
RECORDS. IT IS EXPECTED TO PEAK TOMORROW AFTERNOON AND TUESDAY
MORNING AT AROUND 2.25 TO 2.30 INCHES. BY TOMORROW AND TUESDAY,
WINDS ARE EXPECTED TO SHIFT MORE FROM THE SOUTH-SOUTHEASTERLY DUE
TO THE INFLUENCE OF HURRICANE MELISSA'S TRACK. THIS PATTERN WILL
MAINTAIN TROPICAL MOISTURE POOLING, RESULTING IN ABOVE-NORMAL
MOISTURE CONTENT. AS A RESULT, THE FLOOD POTENTIAL WILL REMAIN
FROM LIMITED TO ELEVATED ACROSS PORTIONS OF PUERTO RICO, WITH
DAILY SHOWER ACTIVITY AND POSSIBLE THUNDERSTORMS. ACROSS THE U.S.
VIRGIN ISLANDS, PASSING SHOWERS MAY OCCUR INTERMITTENTLY EACH DAY,
BUT SIGNIFICANT IMPACTS ARE NOT ANTICIPATED. ADDITIONALLY, WARMER
TEMPERATURES ARE EXPECTED ON TUESDAY AS THE 925 MB TEMPERATURES
CONTINUE TO SHOW AN INCREASING TREND, ALONGSIDE THE MOISTURE
CONTENT AND SOUTHERLY FLOW. KEEP IN MIND THAT THIS MAY CONTRIBUTE
TO STRONGER CONVECTION DURING THE AFTERNOONS IF THE CLOUD COVER
DIMINISHES DURING THE MORNINGS.
LONG TERM
(WEDNESDAY THROUGH SUNDAY)
ISSUED AT 257 PM AST SUN OCT 26 2025
CONFIDENCE IN THE LONG-TERM FORECAST IS INCREASING AS WEATHER MODELS
ARE BEGINNING TO AGREE ON THE OVERALL SYNOPTIC PATTERN, BUT WITH
SLIGHT TEMPORAL DIFFERENCES AT THE END OF THE PERIOD. THE NOW MAJOR
HURRICANE MELISSA IS EXPECTED TO ENTER THE WESTERN ATLANTIC WATERS
BY LATE WEDNESDAY, FAR AWAY FROM THE CWA. NEVERTHELESS, TRAILING
MOISTURE ASSOCIATED WITH THIS CYCLONE MAY POOL INTO THE REGION FOR
THE SECOND PART OF THE WORKWEEK. ALTHOUGH THE BEST MOISTURE CONTENT
SHOULD REMAIN OVER THE HISPANIOLA, BASED ON THE LATEST DETERMINISTIC
GUIDANCE FROM THE GFS AND ECMWF, PRECIPITABLE WATER (PWAT) VALUES
ARE EXPECTED TO RANGE BETWEEN 1.8 AND 2.0 INCHES, NEAR TO ABOVE
CLIMATOLOGICAL NORMAL, ACROSS THE CWA. UNDER A SOUTHEASTERLY-
SOUTHERLY WIND PATTERN, AN ADVECTIVE PATTERN IS STILL LIKELY TO
PREVAIL DURING THE NIGHT AND MORNING HOURS WITH SHOWERS AND ISOLATED
THUNDERSTORMS OVER THE WINDWARD SECTIONS OF THE ISLANDS. CONSIDERING
DAYTIME HEATING, LOCAL EFFECTS, AND THE AVAILABLE MOISTURE CONTENT,
AFTERNOON CONVECTION IS LIKELY TO DEVELOP OVER THE MOUNTAIN RANGES
OF PUERTO RICO, THEREBY INCREASING THE POTENTIAL FOR FLOODING.
HENCE, THE FLOODING THREAT WILL REMAIN LIMITED TO ELEVATED ACROSS
THE AFOREMENTIONED AREAS. FOR THE UPCOMING WEEKEND, MODEL GUIDANCE
STILL SUGGESTS THE APPROACH OF AN UPPER-LEVEL LOW INTO THE REGION,
INCREASING INSTABILITY AND MOISTURE CONTENT ONCE AGAIN ACROSS THE
CWA. ALTHOUGH THE ARRIVAL OF THIS FEATURE IS UNCERTAIN DUE TO
DIFFERENCES BETWEEN MODEL SOLUTIONS, THE FREQUENCY OF SHOWERS AND
THUNDERSTORMS MAY INCREASE BY THE END OF THE FORECAST PERIOD ACROSS
THE LOCAL ISLANDS.
WINDS WITH A SOUTHERLY COMPONENT, ABUNDANT MOISTURE CONTENT, AND
NEAR ABOVE-NORMAL 925 MB TEMPERATURES, HEAT INDEXES DURING PEAK
HOURS OF THE DAY ARE LIKELY TO REACH 100 DEGREES FAHRENHEIT, AND
EVEN MEET HEAT ADVISORY CRITERIA. HENCE, THE HEAT THREAT WILL REMAIN
ELEVATED FOR THE REST OF THE FORECAST PERIOD.
AVIATION
(18Z TAFS)
ISSUED AT 257 PM AST SUN OCT 26 2025
MAINLY VFR CONDITIONS. AFTERNOON SHRA/TSRA WILL AFFECT TJPS/TJBQ/TJSJ
AS WELL AS MAINLY THE VCTY OF TISX/TIST UNTIL AROUND 23Z. THIS
CAN PROMOTE BRIEF MVFR CONDITIONS. VCSH/POSSIBLE VCTS AFFECTING
MAINLY EASTERN AND SOUTHERN COASTS TONIGHT. SE WINDS GENERALLY UP
TO 15 KTS, WITH HIGHER GUSTS (ESPECIALLY NEAR TS) AND SEA BREEZE
VARIATIONS, WILL CONTINUE BEFORE BECOMING LIGHTER WITH LAND
BREEZES AFTER 26/23Z. WINDS PICKING UP AGAIN FROM THE SE AFTER
27/13Z.
MARINE
ISSUED AT 257 PM AST SUN OCT 26 2025
CARICOOS BUOYS INDICATE SEAS AT 3 TO 4 FEET NEAR THE ISLANDS. SEAS
WILL CONTINUE AT 5 TO 6 FEET FOR SECTORS OF THE OFFSHORE ATLANTIC
WATERS THROUGH THIS EVENING. FROM TONIGHT THROUGH AT LEAST WEDNESDAY,
SEAS ARE EXPECTED TO REMAIN BETWEEN 2 TO 4 FEET. LATER IN THE
WEEK, MARINE CONDITIONS WILL DEPEND ON THE ACTUAL TRACK AND
INTENSITY OF HURRICANE MELISSA. THIS HURRICANE IS FORECAST TO
GENERATE A SMALL NORTHWEST SWELL THAT COULD BEGIN REACHING OUR
LOCAL WATERS BY THURSDAY, POSSIBLY LEADING TO A GRADUAL INCREASE
IN WAVE HEIGHTS THEREAFTER. MARINERS ARE ADVISED TO CLOSELY
MONITOR THE EVOLUTION AND TRACK OF HURRICANE MELISSA.
BEACH FORECAST
ISSUED AT 257 PM AST SUN OCT 26 2025
A MODERATE RISK OF RIP CURRENTS WILL CONTINUE TONIGHT AND THROUGH
THE FIRST HALF OF THE WEEK FOR MOST BEACHES IN PUERTO RICO AND THE
U.S. VIRGIN ISLANDS. BY THE MIDWEEK, THE RISK OF RIP CURRENT THREAT
COULD INCREASE TO HIGH ALONG SOME OF THE NORTH FACING BEACHES OF
PUERTO RICO AND USVI DUE TO A SMALL NORTHWEST SWELL FROM HURRICANE
MELISSA. BEACHGOERS ARE ADVISED TO CLOSELY MONITOR THE LOCAL
FORECAST AS WELL AS THE EVOLUTION AND TRACK OF HURRICANE MELISSA FOR
UPDATED INFORMATION. IN ADDITION, SHOWERS AND ISOLATED THUNDERSTORMS
CAN FORM NEAR COASTAL AREAS, ESPECIALLY DURING AFTERNOON HOURS.
ANYONE OUTDOORS SHOULD STAY ALERT FOR RAPIDLY CHANGING WEATHER AND
MOVE INDOORS OR SEEK SHELTER IMMEDIATELY IF THUNDER IS HEARD.
SJU WATCHES/WARNINGS/ADVISORIES
PR...NONE.
VI...NONE.
AM...NONE.
MRR/YZR
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