016
FXCA62 TJSJ 210908
AFDSJU
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN JUAN PR
508 AM AST WED JAN 21 2026
..NEW SHORT TERM, LONG TERM, AVIATION, MARINE, BEACH FORECAST
KEY MESSAGES
ISSUED AT 508 AM AST WED JAN 21 2026
* BREEZY TO WINDY CONDITIONS WILL CONTINUE TODAY, WHICH COULD
CAUSE OUTDOOR ITEMS TO BE BLOWN AROUND OR DAMAGED.
* CHOPPY TO ROUGH SEAS WILL RESULT IN HAZARDOUS MARINE AND COASTAL
CONDITIONS. SMALL CRAFT ADVISORIES AND HIGH RIP CURRENT
STATEMENTS WILL LIKELY REMAIN IN EFFECT THROUGH THE REST OF THE
WORKWEEK.
* FAST MOVING TRADE WIND SHOWERS WILL CONTINUE, RESULTING IN
SLIPPERY ROAD CONDITIONS AND PONDING OF WATER IN LOW-LYING AND
POOR DRAINAGE AREAS. AFTERNOON SHOWERS LIKELY TO DEVELOP OVER
INTERIOR TO WESTERN PR.
* A SURFACE TROUGH MOVING WESTWARD ACROSS THE REGION FROM LATE
TONIGHT INTO FRIDAY WILL GRADUALLY DETERIORATE WEATHER
CONDITIONS, INCREASING THE POTENTIAL FOR SHOWERS AND ISOLATED
THUNDERSTORMS.
SHORT TERM(TODAY THROUGH FRIDAY)
ISSUED AT 508 AM AST WED JAN 21 2026
A VARIABLE WEATHER PATTERN PREVAILED DURING THE NIGHT INTO THE EARLY
MORNING HOURS. SATELLITE AND RADAR IMAGERY SHOWED PATCHES OF
CLOUDINESS AND FREQUENT PASSING SHOWERS ACROSS THE LOCAL WATERS,
BRIEFLY AFFECTING THE EASTERN SECTIONS OF THE MAIN ISLANDS AND THE
U.S. VIRGIN ISLANDS. AROUND 3:00 AM, A MODERATE SHOWER MOVED ACROSS
THE SAN JUAN METROPOLITAN AREA, TRACKING WESTWARD AND AFFECTING
NORTHERN MUNICIPALITIES. THIS SHOWER ACTIVITY WAS ACCOMPANIED BY
GUSTY WINDS, ACCORDING TO UNOFFICIAL WEATHER STATIONS, WITH GUSTS
REPORTED UP TO 21 KNOTS. OVERNIGHT LOW TEMPERATURES RANGED FROM THE
MID TO UPPER 70S ACROSS COASTAL AREAS TO THE LOW 60S ACROSS THE
INTERIOR.
A BROAD SURFACE HIGH PRESSURE OVER THE CENTRAL ATLANTIC WILL BE THE
MAIN WEATHER FEATURE TODAY, RESULTING IN BREEZY CONDITIONS WITH EAST
WINDS UP TO 15 KNOTS. UNDER THIS PATTERN, PATCHES OF MOISTURE
EMBEDDED IN THE WINDS WILL RESULT IN CLOUDINESS AND FREQUENT SHOWERS
MOVING IN AND OUT OF THE REGION. SINCE BREEZY CONDITIONS REMAIN,
MINIMAL RAINFALL ACCUMULATIONS ARE EXPECTED FROM FAST-MOVING
SHOWERS. THEREFORE, FOR THE REST OF THE DAY, RESIDENTS AND VISITORS
SHOULD EXPECT GOOD PERIODS OF SUNSHINE ACROSS WESTERN SECTIONS WITH
PASSING SHOWERS ACROSS EASTERN SECTIONS OF PUERTO RICO AND THE U.S.
VIRGIN ISLANDS. IN THE AFTERNOON, SOME BRIEF SHOWERS ARE FORECAST
ACROSS SOME INTERIOR AREAS WITH NO FLOODING THREAT.
THE WEATHER PATTERN IS FORECAST TO BECOME WETTER AND MARGINALLY
UNSTABLE FROM THURSDAY INTO FRIDAY AS AN INDUCED SURFACE TROUGH
ASSOCIATED WITH A CUT-OFF LOW LOCATED WELL EAST OF THE ISLANDS MOVES
ACROSS THE REGION. ACCORDING TO THE LATEST MODEL GUIDANCE, MOISTURE
IS FORECAST TO INCREASE, WITH PRECIPITABLE WATER VALUES RISING FROM
AROUND 1.5 INCHES ON THURSDAY TO NEAR 1.70 INCHES ON FRIDAY, ABOVE
CLIMATOLOGICAL NORMALS. ON THURSDAY, MOISTURE SHOULD REMAIN MOSTLY
SHALLOW; HOWEVER, AS THE DAY PROGRESSES, 850-500 MB RELATIVE
HUMIDITY VALUES SHOW DEEP MOISTURE MOVING INTO THE ISLANDS. THE
PRESENCE OF ABUNDANT MOISTURE WILL COMBINE WITH MARGINALLY UNSTABLE
CONDITIONS AT THE MID AND UPPER LEVELS DUE TO A STRONG JET STREAK
OVER THE AREA, PROVIDING UPPER DIVERGENCE, AND MARGINALLY COLDER
TEMPERATURES AT 500 MB (-7 TO -8 DEGREES). GIVEN THE EXPECTED
CONDITIONS, RESIDENTS CAN EXPECT AN INCREASE IN MORNING SHOWERS,
FOLLOWED BY MORE ORGANIZED SHOWERS ACROSS THE MOUNTAIN AND WESTERN
SECTIONS. SURFACE WINDS WILL REMAIN BREEZY; HOWEVER, WITH THE
PASSAGE OF THE INDUCED SURFACE TROUGH, WINDS ARE EXPECTED TO
DECREASE TO AROUND 15 KNOTS ON THURSDAY. AS A RESULT, RESIDENTS AND
VISITORS CAN EXPECT SHOWERS AND ISOLATED THUNDERSTORMS, WHICH SHOULD
BRING PERIODS OF HEAVY RAINFALL AND GUSTY WINDS, RESULTING IN
PONDING OF WATER OVER ROADWAYS, URBAN AREAS, AND POORLY DRAINED
AREAS, WITH MINOR FLOODING IN THESE AREAS. ADDITIONALLY, REDUCED
VISIBILITY AND LIGHTNING CANNOT BE RULED OUT. THEREFORE, FOR THE
HAZARDS ON THURSDAY INTO FRIDAY, A FLOODING AND LIGHTNING RISK WILL
REMAIN LIMITED.
LONG TERM(SATURDAY THROUGH WEDNESDAY)
ISSUED AT 508 AM AST WED JAN 21 2026
INCREASED MOISTURE AND INSTABILITY WILL CARRY FROM THE SHORT TERM
PERIOD INTO SATURDAY, AS THE MOISTURE FIELD FROM THE DISTURBANCE
CONTINUES OVER THE REGION PROMOTING ABOVE SEASONAL PRECIPITABLE
WATER (PWAT) VALUES (1.50 TO NEAR 2 INCHES). SATURDAY LOOKS TO BE
THE WETTEST DAY IN THE LONG TERM PERIOD, WITH ADVECTIVE SHOWERS
STEERED BY EASTERLY FLOW AND CONVECTIVE AFTERNOON SHOWERS OVER
INTERIOR TO WESTERN PR. IMPROVED WEATHER CONDITIONS ARE FORECAST
FROM LATE SATURDAY THROUGH SUNDAY AS THE ATMOSPHERIC DISTURBANCE
AND MOISTURE FIELD MOVES WESTWARD AND OUT OF THE REGION AND DRIER
AIR ADVECTS INTO THE AREA. PATCHES OF DRIER AND MOIST AIR WILL
THEN PROMOTE SEASONAL (<1.50 IN) TO BELOW SEASONAL (<1.20 IN) PWAT
VALUES OVER THE AREA. A DOMINANT HIGH-PRESSURE SYSTEM OVER THE
ATLANTIC WILL ESTABLISH A GENERALLY MORE SEASONAL EASTERLY
STEERING FLOW, MOVING ADVECTIVE SHOWERS INTO WINDWARD AREAS,
PARTICULARLY IN THE MORNING AND OVERNIGHT HOURS. SUBSIDENCE IN THE
MID-TO-UPPER LEVELS OF THE ATMOSPHERE WILL INHIBIT SHOWER
DEVELOPMENT; HOWEVER, LOCALIZED EFFECTS MAY STILL INDUCE
CONVECTIVE SHOWERS, THOUGH NO FLOODING IS ANTICIPATED. MOST
AVAILABLE MOISTURE WILL BE LIMITED TO BELOW 800 MB. THE LIMITED
WIND RISK WILL GRADUALLY SUBSIDE DURING THE WEEKEND. 925 MB
TEMPERATURES WILL REMAIN AT SEASONAL VALUES, OVERNIGHT PATCHY FOG
IS ALSO FORECAST OVER AREAS OF THE INTERIOR. MODEL GUIDANCE
SUGGESTS THAT VARIATIONS IN THIS PATTERN WILL OCCUR DUE TO AN
UPPER TROUGH MOVING EAST OF THE REGION TO START THE WORKWEEK AND A
SHIFT IN EASTERLY FLOW ON WEDNESDAY TO BECOME MORE NORTHEASTERLY.
AVIATION
(06Z TAFS)
ISSUED AT 508 AM AST WED JAN 21 2026
VFR CONDITIONS WILL PERSIST ACROSS THE TAF SITES. WINDS WILL
PERSIST FROM THE E AT 10 KNOTS, INCREASING UP TO 15 KNOTS WITH
GUSTY WINDS UP TO 25 KNOTS FROM 21/14Z LASTING DURING THE DAY.
VCSH TO SHRA ARE EXPECTED MOSTLY ACROSS EASTERN SITES FROM NOW
THROUGH 21/18Z, INCREASING EVEN MORE WITH REDUCTION IN VIS AND
CIGS AT 22/03Z AS CLOUDINESS AND SHOWERS FROM AN INDUCED SURFACE
TROUGH MOVE ACROSS THE AREA.
MARINE
ISSUED AT 508 AM AST WED JAN 21 2026
A BROAD SURFACE HIGH PRESSURE OVER THE CENTRAL ATLANTIC WILL
CONTINUE TO STRENGTHEN DURING THE NEXT FEW DAYS, TIGHTENING THE
LOCAL PRESSURE GRADIENT AND PROMOTING FRESH TO LOCALLY STRONG
EASTERLIES THROUGH MUCH OF THE REST OF WORKWEEK. THIS STRONG
SURFACE HIGH PRESSURE WILL MAINTAIN THE FRONTAL BOUNDARY OFF TO
THE WEST OF THE NORTHEAST CARIBBEAN. A SURFACE TROUGH WILL MOVE
ACROSS THE NORTHEAST CARIBBEAN AROUND THURSDAY, AFFECTING PUERTO
RICO AND THE US VIRGIN ISLANDS THROUGH SATURDAY.
BEACH FORECAST
ISSUED AT 508 AM AST WED JAN 21 2026
A HIGH RISK OF RIP CURRENTS REMAINS IN EFFECT ACROSS THE NORTHERN
COASTS OF PUERTO RICO, AS WELL AS FOR CULEBRA, AND THE U.S.
VIRGIN ISLANDS, DUE TO HAZARDOUS CONDITIONS WITH BREAKING WAVES UP
TO 6 TO 7 FEET. AN INCREASE IN SURFACE WINDS FROM THE EAST WILL
INDUCE CHOPPY SEAS, RESULTING IN LOCALIZED HAZARDS. RESIDENTS AND
VISITORS ARE URGED TO CONTINUE FOLLOWING THE WARNING FLAG SYSTEM
AND TO FAVOR BEACHES WITH LOWER RIP CURRENT RISK, SUCH AS THOSE
ALONG PUERTO RICO'S WESTERN AND SOUTHERN COASTS. UP TO A HIGH RISK
OF RIP CURRENTS IS LIKELY TO CONTINUE THROUGH THE REST OF THE
WORKWEEK.
FOR THE WESTERN AND SOUTHERN COASTAL AREAS, WHERE THE RISK
REMAINS MODERATE, BEACHGOERS CAN EXPECT BREEZY TO LOCALLY WINDY
CONDITIONS TO CONTINUE, WHICH MAY STILL RESULT IN UNSECURED
OBJECTS BEING BLOWN AROUND, PARTICULARLY IN THE MOST EXPOSED
LOCATIONS. BEACHGOERS SHOULD REMAIN CAUTIOUS BOTH IN AND NEAR THE
WATER UNTIL CONDITIONS IMPROVE FURTHER. FOR LOCALIZED, UP-TO-DATE
RISK LEVELS, VISIT: WEATHER.GOV/BEACH/SJU.
SJU WATCHES/WARNINGS/ADVISORIES
PR...HIGH RIP CURRENT RISK THROUGH THURSDAY AFTERNOON FOR PRZ001-002-
005-008-012.
VI...HIGH RIP CURRENT RISK THROUGH THURSDAY AFTERNOON FOR VIZ001-002.
AM...SMALL CRAFT ADVISORY UNTIL 6 PM AST THURSDAY FOR AMZ711-712-716-
723-726-733-741.
SMALL CRAFT ADVISORY FROM MIDNIGHT TONIGHT TO 6 PM AST THURSDAY
FOR AMZ735.
SHORT TERM/AVIATION...LIS
LONG TERM/MARINE/BEACH FORECAST/KEY MESSAGES...MRR
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