937
FXCA62 TJSJ 101846
AFDSJU
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN JUAN PR
246 PM AST SAT JAN 10 2026
..NEW SHORT TERM, LONG TERM, AVIATION, MARINE, BEACH FORECAST
KEY MESSAGES
ISSUED AT 246 PM AST SAT JAN 10 2026
* A MODERATE RISK OF RIP CURRENTS CONTINUES ALONG ATLANTIC-FACING
BEACHES OF PUERTO RICO, WITH THE RISK POSSIBLY EXTENDING TO
WESTERN PUERTO RICO, CULEBRA, AND THE U.S. VIRGIN ISLANDS ON
SUNDAY. DANGEROUS SWIMMING CONDITIONS ARE POSSIBLE AT EXPOSED
BEACHES ACROSS PUERTO RICO AND THE U.S. VIRGIN ISLANDS.
* A TYPICAL TRADE-WIND PATTERN WILL BRING PASSING SHOWERS TO
WINDWARD AREAS OF PUERTO RICO AND THE U.S. VIRGIN ISLANDS,
MAINLY OVERNIGHT AND EARLY IN THE MORNING, WITH LIMITED
AFTERNOON SHOWERS, ESPECIALLY ACROSS SOUTHWESTERN PUERTO RICO.
RAINFALL WILL GENERALLY BE LIGHT, THOUGH LOCALIZED PONDING OR
MINOR FLOODING IS POSSIBLE IN POOR DRAINAGE AREAS OF PUERTO
RICO AND THE U.S. VIRGIN ISLANDS. WIDESPREAD FLOODING IS NOT
EXPECTED.
* COOLER-THAN-NORMAL NIGHTTIME TEMPERATURES WILL CONTINUE ACROSS
PUERTO RICO AND THE U.S. VIRGIN ISLANDS, WITH COMFORTABLE,
NEAR- SEASONAL DAYTIME TEMPERATURES AND GENERALLY FAVORABLE
CONDITIONS FOR OUTDOOR ACTIVITIES ACROSS THE ISLANDS..
SHORT TERM(THIS EVENING THROUGH MONDAY)
ISSUED AT 246 PM AST SAT JAN 10 2026
CLOUDY CONDITIONS DEVELOPED EARLY ACROSS WINDWARD AREAS AS TRADE-
WIND SHOWERS MOVED ONSHORE, FOLLOWED BY LOCALIZED AFTERNOON
SHOWERS OVER SOUTHWESTERN PUERTO RICO, STEERED BY A PERSISTENT
NORTHEASTERLY FLOW. NO FLOODING WAS REPORTED. COOLER TEMPERATURES
PREVAILED ACROSS HIGHER ELEVATIONS, WITH LOWS IN THE LOW 60S AND
HIGHS IN THE LOW 70S, WHILE COASTAL AND INTERIOR URBAN AREAS WERE
WARMER, WITH MAXIMUM TEMPERATURES REACHING THE MID TO UPPER 80S.
AT SAN JUAN INTERNATIONAL AIRPORT, TEMPERATURES RANGED FROM 73°F
TO 84°F. RAINFALL TOTALS REACHED UP TO 1.5 INCHES IN PARTS OF
SOUTHWESTERN PUERTO RICO SINCE MIDDAY, WITH ISOLATED AMOUNTS NEAR
ONE-HALF INCH ACROSS WINDWARD AREAS SINCE MIDNIGHT. WINDS WERE
LIGHT AND VARIABLE EARLY, INCREASING TO EAST-NORTHEAST AT 10–15
MPH WITH SEA-BREEZE VARIATIONS.
A SURFACE HIGH WELL TO THE NORTH WILL MAINTAIN THE OVERALL
NORTHEASTERLY FLOW, ALLOWING COOLER AIR AND SHALLOW MOISTURE TO
MOVE INTO THE REGION. WHILE COOLER AIR ALOFT ASSOCIATED WITH AN
UPPER-LEVEL TROUGH IS PRESENT, DRY MID- LEVELS WILL KEEP MOISTURE
SHALLOW AND CAPPED, LIMITING CONVECTION FROM GROWING DEEP ENOUGH
TO SUPPORT THUNDERSTORM DEVELOPMENT. STILL, THIS PATTERN WILL
FAVOR PASSING TRADE-WIND SHOWERS, MAINLY AFFECTING WINDWARD AREAS
OF THE U.S. VIRGIN ISLANDS, VIEQUES, CULEBRA, AND NORTHERN AND
EASTERN PUERTO RICO, ESPECIALLY LATE TONIGHT AND EARLY IN THE
MORNING. RAINFALL WILL BE BRIEF AND LIGHT, WITH NO FLOODING
EXPECTED, AND OUTDOOR ACTIVITIES MAY BE BRIEFLY AFFECTED. MINIMUM
TEMPERATURES ARE EXPECTED TO DROP BELOW THOSE OBSERVED TODAY AS
COOLER AIR SINKS FARTHER SOUTH AND WINDS BECOME LIGHT AND
VARIABLE, PARTICULARLY ACROSS INTERIOR AND HIGHER-ELEVATION AREAS.
FOG DEVELOPMENT IS LIKELY IN CLOUD-FREE LOCATIONS, MAINLY IN
VALLEYS AND HIGHER TERRAIN.
AS A SURFACE HIGH TO THE NORTH SHIFTS FARTHER EAST AND A WEAK,
SURFACE-INDUCED TROUGH MOVES THROUGH THE REGION, LOW-LEVEL WINDS
WILL VEER SLIGHTLY MORE EASTERLY AT TIMES, BUT THE OVERALL
NORTHEASTERLY STEERING FLOW WILL PERSIST. THIS PATTERN WILL
CONTINUE TO SUPPORT PASSING TRADE-WIND SHOWERS, MAINLY DURING THE
OVERNIGHT AND EARLY-MORNING HOURS ACROSS WINDWARD AREAS. DURING
THE AFTERNOON, LOCAL HEATING WILL HELP INITIATE SHOWERS, AND THE
PERSISTENT NORTHEASTERLY FLOW WILL PUSH ACTIVITY TOWARD WESTERN
AND SOUTHWESTERN PUERTO RICO, WHERE LOW-LEVEL CONVERGENCE AGAINST
THE SEA BREEZE WILL BE STRONGEST. RAINFALL WILL GENERALLY BE LIGHT
AND BRIEF, THOUGH AN ISOLATED HEAVIER SHOWER COULD CAUSE MINOR
PONDING IN LOW-LYING OR POOR-DRAINAGE AREAS; WIDESPREAD FLOODING
IS NOT EXPECTED. COOLER-THAN-NORMAL AND COMFORTABLE TEMPERATURES
WILL CONTINUE THROUGH SUNDAY AND MONDAY, WITH COOL NIGHTS AND
GENERALLY FAVORABLE CONDITIONS FOR OUTDOOR ACTIVITIES, ASIDE FROM
BRIEF INTERRUPTIONS FROM PASSING SHOWERS.
LONG TERM(TUESDAY THROUGH NEXT FRIDAY)
ISSUED AT 420 AM AST SAT JAN 10 2026
A DEEP-LAYER MID-TO-UPPER-LEVEL TROUGH WILL CONTINUE MOVING
EASTWARD AND AWAY FROM THE LESSER ANTILLES FROM TUESDAY ONWARD. AT
THE SAME TIME, A MID-TO-UPPER-LEVEL RIDGE BUILDS OVER THE
NORTHEAST CARIBBEAN. AT THE SURFACE, AN ABNORMALLY STRONG AZORES
HIGH WILL PERSIST OVER THE NORTH ATLANTIC. THIS PATTERN WILL KEEP
FRONTAL BOUNDARIES EXITING THE EASTERN SEABOARD WELL NORTH OF
PUERTO RICO AND THE US VIRGIN ISLANDS, LIMITING ANY DIRECT FRONTAL
INFLUENCE OVER THE LOCAL AREA THROUGH AT LEAST THE END OF THE
UPCOMING WORKWEEK. THEN, ECMWF AND GFS INDICATED A FRONTAL
BOUNDARY APPROACHING THE REGION. IF IT GETS CLOSE ENOUGH, IT COULD
PROMOTE INCREASED AVAILABLE MOISTURE AND THE POTENTIAL FOR AN
UNSTABLE WET PATTERN AROUND FRIDAY AND NEXT SATURDAY.
UNDER THIS CONFIGURATION, THE PREVAILING WEATHER WILL BE
DOMINATED BY A TYPICAL TRADE-WIND (ADVECTIVE) PATTERN. THIS WILL
FAVOR OCCASIONAL PERIODS OF PASSING SHOWERS, MAINLY AFFECTING
WINDWARD LOCATIONS OF PUERTO RICO AND THE US VIRGIN ISLANDS,
INCLUDING THE EASTERN AND NORTHEASTERN COASTAL AREAS. THESE
SHOWERS ARE EXPECTED TO BE BRIEF, WITH LIMITED RAINFALL
ACCUMULATION. AS THE MID-TO UPPER-LEVEL RIDGE STRENGTHENS,
ATMOSPHERIC STABILITY IS EXPECTED TO INCREASE. THIS WILL RESULT IN
REDUCED AFTERNOON CONVECTION OVER WESTERN PUERTO RICO, COMPARED
TO MORE UNSETTLED PATTERNS. ANY AFTERNOON SHOWERS THAT DO DEVELOP
ARE EXPECTED TO BE ISOLATED AND SHORT-LIVED.
ENSEMBLE MODEL GUIDANCE INDICATES THAT TEMPERATURES OVER THE LONG
TERM WILL RANGE FROM NEAR-NORMAL TO SLIGHTLY ABOVE-NORMAL ACROSS
PUERTO RICO AND THE US VIRGIN ISLANDS.
AVIATION
(18Z TAFS)
ISSUED AT 246 PM AST SAT JAN 10 2026
MAINLY VFR CONDS EXPECTED AT ALL TAF SITES. BRIEF VCSH/SHRA WILL
CONTINUE AS TRADE-WIND SHRA MOVE INLAND OVER THE NEXT 12–18 HRS,
WITH LOCALLY INDUCED SHRA MAINLY AFFECTING SOUTHERN TERMINALS,
POTENTIALLY CAUSING BRIEF MVFR CIGS AT TJPS THRU ~10/21Z. SHRA
COVERAGE WILL DECREASE AFTER 11/14Z, BECOMING ISOLATED AND MAINLY
CONFINED TO NORTHERN TERMINALS. SFC WINDS E–NE 10–14 KT, BECOMING
LGT/VRB (<6 KT) AFTER 10/22Z, THEN INCR TO 10–15 KT WITH SEA-
BREEZE VAR AFT 11/13Z.
MARINE
ISSUED AT 246 PM AST SAT JAN 10 2026
SURFACE HIGH PRESSURE MIGRATING EASTWARD ACROSS THE WESTERN
ATLANTIC, IN COMBINATION WITH A WEAK SURFACE-INDUCED TROUGH
NORTHEAST OF THE REGION, WILL MAINTAIN MODERATE EAST TO NORTHEAST
WINDS ACROSS THE LOCAL WATERS THROUGH THE MIDDLE OF NEXT WEEK.
THIS PATTERN WILL SUPPORT PASSING TRADE-WIND SHOWERS, MAINLY
ACROSS THE ATLANTIC WATERS, WITH OCCASIONAL SHOWERS ALSO MOVING
THROUGH THE CARIBBEAN PASSAGES AT TIMES. OVERALL MARINE CONDITIONS
ARE EXPECTED TO REMAIN GENERALLY FAVORABLE, THOUGH BRIEF
REDUCTIONS IN VISIBILITY ARE POSSIBLE IN HEAVIER SHOWERS.
BEACH FORECAST
ISSUED AT 246 PM AST SAT JAN 10 2026
A MODERATE RISK OF RIP CURRENTS WILL CONTINUE ALONG NORTH-FACING
BEACHES OF PUERTO RICO, AS WELL AS CULEBRA AND PORTIONS OF THE
U.S. VIRGIN ISLANDS. WHILE THE RISK IS NOT EXPECTED TO INCREASE,
DANGEROUS RIP CURRENTS WILL REMAIN POSSIBLE, PARTICULARLY ALONG
EXPOSED BEACHES. BEACHGOERS ARE URGED TO EXERCISE CAUTION, STAY
NEAR LIFEGUARDED BEACHES WHEN AVAILABLE, AND AVOID ENTERING THE
WATER IF CONDITIONS APPEAR UNSAFE.
SJU WATCHES/WARNINGS/ADVISORIES
PR...NONE.
VI...NONE.
AM...NONE.
ICP/MMC
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