174
FXCA62 TJSJ 211715
AFDSJU
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN JUAN PR
115 PM AST FRI NOV 21 2025
..NEW SHORT TERM, AVIATION, MARINE, BEACH FORECAST
KEY MESSAGES
ISSUED AT 100 PM AST FRI NOV 21 2025
* LIMITED SHOWER ACTIVITY IS EXPECTED ACROSS PUERTO RICO OVER
THE NEXT FEW DAYS, WITH NO HAZARD THREATS ANTICIPATED AT THIS
TIME.
*A FAIR-WEATHER PATTERN WILL CONTINUE TO PREVAIL ACROSS THE U.S.
VIRGIN ISLANDS, WITH NO HAZARDS EXPECTED.
*LIFE-THREATENING RIP CURRENTS WILL REMAIN POSSIBLE ALONG THE
NORTH- AND EAST-FACING BEACHES OF PUERTO RICO AND THE U.S.
VIRGIN ISLANDS THROUGH SATURDAY EVENING.
SHORT TERM (THIS EVENING THROUGH SUNDAY)
ISSUED AT 100 PM AST FRI NOV 21 2025
MOSTLY SUNNY SKIES PREVAILED DURING THE MORNING HOURS, BECOMING
PARTLY CLOUDY BY THE AFTERNOON, PARTICULARLY ACROSS WESTERN AND
SOUTHWESTERN PUERTO RICO. ISOLATED AFTERNOON SHOWERS HAVE BEGUN
TO DEVELOP OVER WESTERN AREAS; HOWEVER, THESE ARE EXPECTED TO
DISSIPATE NEAR SUNSET, LEAVING PARTLY CLOUDY SKIES. MAXIMUM
TEMPERATURES RANGED FROM THE MID-80S TO 90 DEGREES ACROSS THE
LOWER ELEVATIONS.
A MID-LEVEL RIDGE WILL CONTINUE TO BUILD OVER THE FORECAST AREA
AS A DEEP POLAR TROUGH SHIFTS EASTWARD AND GRADUALLY DISSIPATES.
AT LOWER LEVELS, A SURFACE HIGH-PRESSURE SYSTEM OVER THE WESTERN
TROPICAL ATLANTIC WILL MAINTAIN A MODERATE EAST-NORTHEAST WIND
FLOW THROUGH THE NEXT FEW DAYS. AS THE UPPER-LEVEL RIDGE
STRENGTHENS, MOISTURE ACROSS THE EASTERN CARIBBEAN WILL STEADILY
ERODE, WITH PRECIPITABLE WATER VALUES REMAINING BELOW 1.5 INCHES.
NEVERTHELESS, THE SURFACE HIGH WILL CONTINUE TO BRING PATCHES OF
MOISTURE AT TIMES.
AS A RESULT, A SEASONABLE WEATHER PATTERN WILL DOMINATE THE
FORECAST CYCLE, WITH LIMITED AFTERNOON SHOWER DEVELOPMENT ACROSS
SOUTHWEST PUERTO RICO. ELSEWHERE, FAIR WEATHER CONDITIONS ARE
EXPECTED TO PREVAIL. HIGH TEMPERATURES WILL CONTINUE TO RANGE FROM
THE MID-80S TO AROUND 90°F ACROSS THE LOWER ELEVATIONS, WHILE
NIGHTTIME LOWS IN THE HIGHER TERRAIN MAY DROP INTO THE MID-50S
UNDER CLEARER SKIES.
LONG TERM (MONDAY THROUGH FRIDAY)
ISSUED AT 423 AM AST FRI NOV 21 2025
MODEL GUIDANCE IS TRENDING TOWARD GREATER CONSENSUS, SUGGESTING A
POTENTIAL CLIMATOLOGICAL PATTERN ACROSS THE NORTHEAST CARIBBEAN,
INCLUDING PUERTO RICO AND THE US VIRGIN ISLANDS. HOWEVER, A SHORT-
WAVE TROUGH ALOFT WILL SWING BY THE REGION FROM THE WEST,
INCREASING THE POTENTIAL FOR AFTERNOON CONVECTION (30-50 PERCENT
CHANCE OF PRECIPITATION), ESPECIALLY AROUND MONDAY AFTERNOON INTO
THE EVENING ALONG THE CORDILLERA CENTRAL AND CROSSING THE USVI.
FROM TUESDAY INTO THURSDAY, THERE IS A BETTER AGREEMENT THAT HIGH
PRESSURE AT MID LEVELS WILL PROMOTE SUBSIDENCE AND A TRADE WIND
INVERSION OVER THE REGION, TRAPPING ALL THE MOISTURE AT LOW
LEVELS. THUS, WE EXPECT A MIXTURE OF SUNSHINE AND CLOUDS, WITH
OCCASIONAL PATCHES OF MOISTURE EMBEDDED IN THE TRADES BRINGING
SHOWERY WEATHER OVER THE WINDWARD LOCATIONS OF PR AND THE USVI.
HOWEVER, THIS ACTIVITY DOES NOT REPRESENT A FLOODING THREAT FOR
THE REGION.
TEMPERATURES ACROSS THE ISLANDS ARE EXPECTED TO CONTINUE COOLING.
MODEL FORECASTS SUGGEST THAT TEMPERATURES AT 925 MB WILL BE
SLIGHTLY BELOW NORMAL, ROUGHLY AT THE 25TH PERCENTILE COMPARED TO
TYPICAL NOVEMBER CONDITIONS. HOWEVER, THERE MAY BE INSTANCES,
PARTICULARLY DURING PEAK HEATING IN THE AFTERNOON, WHEN
TEMPERATURES CAN REACH NEAR-NORMAL LEVELS (AROUND THE 50TH
PERCENTILE).
AVIATION
(18Z TAFS)
ISSUED AT 100 PM AST FRI NOV 21 2025
VFR WILL PREVAIL THRU THE PRD ACROSS ALL TAF SITES. HOWEVER, BRIEF
VCTS PSBL NR TJPS AFTER 22/1700Z. VCSH POSSIBLE AFTER 22/23Z OVER
TISX/TIST DURING THE OVERNIGHT HOURS, WINDS FROM THE NORTHEAST UP TO
15 KTS AND SOME SEA BREEZE VARIATIONS THROUGH 22/22Z, BCMNG LIGHT
AND VRB AFTER 22/23Z.
MARINE
ISSUED AT 100 PM AST FRI NOV 21 2025
A SURFACE HIGH WILL BUILD OVER THE WESTERN ATLANTIC DURING THE
NEXT FEW DAYS, PROMOTING A MODERATE EAST-NORTHEAST WIND FLOW. A
SURFACE LOW OVER THE EASTERN ATLANTIC WILL GENERATE PULSES OF
LONG-PERIOD NORTHEASTERLY SWELLS, ARRIVING AROUND TUESDAY OR
WEDNESDAY OF NEXT WEEK. SEAS BELOW SCA CRITERIA AT LEAST
THROUGH THE UPCOMING WORKWEEK.
BEACH FORECAST
ISSUED AT 100 PM AST FRI NOV 21 2025
A MODERATE RISK OF RIP CURRENTS WILL PREVAIL FOR THE NORTH AND
EAST-FACING BEACHES THROUGH AT LEAST LATE SATURDAY NIGHT. THE RISK
IS FORECAST TO BE LOW FROM SUNDAY TO TUESDAY EVENING. THEN,
ANOTHER LONG-PERIOD NORTHEASTERLY SWELL WILL INCREASE THE RISK TO
MODERATE OR HIGH FROM LATE TUESDAY NIGHT INTO THE MIDDLE OF NEXT
WEEK.
SJU WATCHES/WARNINGS/ADVISORIES
PR...NONE.
VI...NONE.
AM...NONE.
SHORT TERM...OMS
LONG TERM....CAM
AVIATION...MMC
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