928
FXCA62 TJSJ 080938
AFDSJU
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN JUAN PR
538 AM AST WED OCT 8 2025
KEY MESSAGES
* ANOTHER ACTIVE DAY IS EXPECTED ACROSS THE ISLANDS WITH PERIODS
OF HEAVY RAINFALL AND THUNDERSTORM ACTIVITY. THERE IS A LIMITED
TO ELEVATED FLOODING RISK, PARTICULARLY OVER THE NORTHWESTERN
QUADRANT OF PUERTO RICO.
* FREQUENT LIGHTNING, GUSTY WIND CONDITIONS, AND URBAN OR SMALL-
STREAM FLOODING ARE POSSIBLE, WITH ISOLATED FLASH FLOODING
CANNOT BE RULED OUT.
* A HEAT ADVISORY IS IN EFFECT FOR THE COASTAL AND URBAN AREAS OF
PUERTO RICO FROM 10 AM TO 4 PM AST. VULNERABLE GROUPS AND
OUTDOOR WORKERS SHOULD STAY AWARE OF THESE CONDITIONS. REMEMBER
TO DRINK PLENTY OF FLUIDS, STAY IN AN AIR-CONDITIONED ROOM AND
OUT OF THE SUN DURING THE PEAK HEAT HOURS.
* FOR THE US VIRGIN ISLANDS, MINOR FLOODING AND LIGHTNING POSSIBLE
TODAY DUE TO SHOWERS AND THUNDERSTORMS ACROSS THE AREA.
* THE NATIONAL HURRICANE CENTER (NHC) CONTINUES MONITORING
TROPICAL STORM JERRY, LOCATED OVER THE CENTRAL ATLANTIC. THIS
SYSTEM IS EXPECTED TO APPROACH THE NORTHEAST CARIBBEAN BY
FRIDAY. RESIDENTS AND VISITORS SHOULD REMAIN INFORMED AND
MONITOR OFFICIAL UPDATES FROM THE NATIONAL HURRICANE CENTER AND
OUR LOCAL OFFICE AS JERRY APPROACHES THE LESSER ANTILLES.
SHORT TERM...TODAY THROUGH FRIDAY
CURRENT SATELLITE DERIVED PRECIPITABLE WATER (PWAT) VALUES SHOW
GENERALLY ABOVE 2 INCHES OVER THE ISLANDS WITH ISOLATED SECTORS AT
AROUND 1.8 IN. A TROPICAL WAVE OVER THE REGION AND A WEAKENING UPPER
LEVEL LOW WNW OF PR CONTINUE TO CONTRIBUTE TO THIS PLUME OF MOISTURE
OVER THE REGION. SINCE MIDNIGHT, MOST SHOWERS AND T-STORMS REMAINED
OVER THE LOCAL WATERS, WITH SOME LEAVING LOW RADAR ESTIMATED
ACCUMULATIONS OVER EASTERN PR, VIEQUES, AND CULEBRA. THE HIGHEST
RADAR ESTIMATED ACCUMULATIONS AS OF 445 PM WERE OBSERVED OVER
CENTRAL ST. CROIX, AT 0.30 IN. LOWS WERE IN THE MID 70S TO LOW 80S
OVER COASTAL AND URBAN AREAS OF PUERTO RICO AND IN THE MID 60S OVER
INTERIOR PUERTO RICO. LOWS WERE IN THE UPPER 70S TO LOW 80S OVER THE
USVI, CULEBRA AND VIEQUES.
AS THE WAVE CONTINUES TO MOVE WEST-NORTHWESTWARD, SOUTHEASTERLY
STEERING FLOW WILL PERSIST, BRINGING MOISTURE INTO THE ISLANDS. PWAT
WILL REMAIN NEAR OR ABOVE 2.0 INCHES THROUGH THE SHORT-TERM PERIOD,
WITH CURRENT MODEL GUIDANCE NOT BEING AS AGGRESSIVE WITH DRIER AIR
INTRUSION AS BEFORE, FOR TODAY, LEAVING PWAT VALUES AT AROUND 1.88
INCHES OVER SOUTH AND WESTERN PUERTO RICO. IN GENERAL HIGH END
NORMAL TO ABOVE NORMAL VALUES WILL CONTINUE DURING THE PERIOD AS
MOISTURE CONTINUES TO BE STEERED OVER THE ISLANDS. THE UPPER LEVEL
LOW WILL CONTINUE MOVING NORTHWARD TODAY, AS AN UPPER LEVEL RIDGE
STARTS TO DOMINATE. 500 MB TEMPERATURES ARE FORECAST TO REMAIN AT
NORMAL VALUES AT AROUND -7 TO -5 DEGREES CELSIUS, GRADUALLY
DECREASING DURING THE PERIOD. 925 MB TEMPERATURES WILL BE NORMAL TO
ABOVE NORMAL DURING THE PERIOD, THIS AND AVAILABLE MOISTURE WILL
MAINTAIN ABOVE-NORMAL TEMPERATURES AND ELEVATED HEAT INDICES, OVER
COASTAL AND URBAN AREAS UNDER PERIODS OF REDUCED CLOUD COVERAGE. A
LIMITED TO ELEVATED HEAT RISK WILL BE IN EFFECT TODAY. A LIMITED TO
ELEVATED FLOODING RISK WILL PERSIST WITH CONVECTIVE SHOWERS AND
THUNDERSTORMS FORECAST FOR INTERIOR TO WESTERN, NORTHERN AND
NORTHWESTERN PUERTO RICO TODAY, WITH LINES OF CONVECTION ALSO
POSSIBLE DOWNWIND OF THE LOCAL ISLANDS AND EL YUNQUE. ADVECTIVE
SHOWER AND ISOLATED T-STORM ACTIVITY IS ALSO FORECAST TO AFFECT
WINDWARD SECTORS OF THE ISLANDS DURING THE MORNING AND OVERNIGHT
HOURS AS THE NEARBY ABOVE MENTIONED FEATURES PROVIDE ENOUGH
INSTABILITY AND MOISTURE AND AS TROPICAL STORM JERRY CONTINUES TO
APPROACH THE CARIBBEAN. HAZARDS INCLUDE LIGHTNING, GUSTY WINDS,
PONDING OF WATER AND LOCALIZED FLOODING ASSOCIATED WITH AFTERNOON T-
STORMS. MINOR TO ISOLATED FLASH FLOODING WILL BE POSSIBLE,
ESPECIALLY IN AREAS WITH POOR DRAINAGE OR WITH MORE PERSISTENT RAIN.
ON THURSDAY AND FRIDAY, THE WEATHER PATTERN WILL BE INFLUENCED BY
TROPICAL STORM JERRY, WHICH IS CURRENTLY AROUND 975 MI SE OF ST.
CROIX, AT COORDINATES 13.3N, 50.7W. THE LATEST ADVISORY HAS JERRY AS
A HURRICANE WITH ITS CLOSEST APPROACH BEING 196 MILES NE OF ST. JOHN
ON FRIDAY MORNING. HOWEVER, UNCERTAINTY REMAINS REGARDING ITS TRACK
AND INTENSITY FORECAST. UNDER THE LATEST GUIDANCE SHOWERS AND
AFTERNOON CONVECTION ARE STILL FORECAST TO BE UNDER SOUTHEASTERLY
FLOW ON THURSDAY AND MORE SOUTHWESTERLY FLOW ON FRIDAY. RESIDENTS
AND VISITORS SHOULD REMAIN INFORMED AND MONITOR OFFICIAL UPDATES
FROM THE NATIONAL HURRICANE CENTER AND OUR LOCAL OFFICE.
LONG TERM...SATURDAY THROUGH WEDNESDAY
THE FORECAST REMAINS ON TRACK, WITH THE ARRIVAL OF TRAILING MOISTURE
ASSOCIATED WITH TROPICAL STORM JERRY. LATEST PRECIPITABLE WATER
(PWAT) GUIDANCE INDICATES VALUES ABOVE THE NORMAL CLIMATOLOGICAL
RANGE (2.25 TO 2.50 INCHES) ACROSS THE REGION. THIS SUGGESTS A WET
AND MOIST PATTERN IS LIKELY FROM SATURDAY THROUGH AT LEAST MONDAY
ACROSS PUERTO RICO AND THE U.S. VIRGIN ISLANDS. AS TROPICAL STORM
JERRY TRACKS NORTH OF THE REGION, PREVAILING WINDS WILL INITIALLY BE
SOUTHEASTERLY, THEN WILL SHIFT FROM THE SOUTHEAST STARTING SUNDAY.
SHOWERS AND THUNDERSTORMS ARE EXPECTED THIS WEEKEND, A RESULT OF THE
HIGH MOISTURE ENVIRONMENT COMBINED WITH DAYTIME HEATING AND LOCAL
EFFECTS. WHILE MOST OF THE AREA WILL EXPERIENCE SOME ACTIVITY
ASSOCIATED WITH THE SYSTEM, THE U.S. VIRGIN ISLANDS ARE EXPECTED TO
OBSERVE MOST OF THE ACTIVITY DUE TO THEIR CLOSER PROXIMITY TO THE
STORM'S PATH. PORTIONS OF EASTERN PUERTO RICO, CULEBRA, AND VIEQUES
WILL ALSO OBSERVE FREQUENT SHOWERS. ON SATURDAY, WITH WINDS
PREVAILING FROM THE SOUTH, ACTIVITY WILL BE FOCUSED OVER CENTRAL AND
NORTHERN PUERTO RICO, INCLUDING THE SAN JUAN METRO AREA, MAINLY
DURING THE AFTERNOON HOURS. FROM SUNDAY ONWARD, AS WINDS SHIFT FROM
THE SOUTHEAST, THE ACTIVITY WILL PRIMARILY FOCUS OVER CENTRAL PUERTO
RICO TOWARD THE NORTHWESTERN QUADRANT OF THE ISLAND.
UNDER THIS PERSISTENT MOIST PATTERN, THE RISK OF FLOODING REMAINS
ELEVATED THROUGH THE BEGINNING OF THE WORKWEEK. ADDITIONAL HAZARDS
INCLUDE: URBAN AND SMALL STREAM FLOODING, MINOR FLOODING IN LOW-
LYING AREAS, QUICK RIVER RISES, THE POTENTIAL FOR LANDSLIDES, AND
FREQUENT LIGHTNING.
CONDITIONS ARE EXPECTED TO IMPROVE QUICKLY STARTING TUESDAY AS A
SURFACE HIGH-PRESSURE SYSTEM AND A MID-LEVEL RIDGE SETTLE OVER THE
CENTRAL ATLANTIC. THIS PATTERN WILL PROMOTE DRIER AND MORE STABLE
ATMOSPHERIC CONDITIONS THROUGH THE END OF THE FORECAST PERIOD.
RESIDENTS AND VISITORS ARE URGED TO CONTINUE MONITORING THE PROGRESS
OF TROPICAL STORM JERRY AND UPDATES FROM THE NATIONAL HURRICANE
CENTER AND OUR LOCAL OFFICE AS THE SYSTEM APPROACHES THE LESSER
ANTILLES.
AVIATION
(06Z TAFS)
MAINLY VFR CONDITIONS TO PREVAIL. DUE TO A TROPICAL WAVE, SHRA AND
TSRA OVER THE WATERS CAN REACH OR MOVE CLOSE TO TJSJ/TIST/TISX/TJPS,
UNDER ESE STEERING FLOW, DURING THE PERIOD. AFTER AROUND 17Z,
SHRA/TSRA OVER THE CORDILLERA WILL SPREAD MAINLY TO
WESTERN/NORTH/NORTHWESTERN AFFECTING PR’S TERMINALS OR THEIR VCTY,
MAINLY TJSJ/TJBQ. THESE CAN PRODUCE BRIEF PERIODS OF REDUCED
VISIBILITIES AND LOWER CEILINGS. WINDS UP TO AROUND 12 KTS WITH SEA
BREEZE VARIATIONS AND HIGHER GUSTS, DECREASING AFTER 8/23Z.
MARINE
MOISTURE ASSOCIATED WITH A TROPICAL WAVE WILL INFLUENCE THE REGION
TODAY, INCREASING THE FREQUENCY OF SHOWERS AND THUNDERSTORMS OVER
THE REGIONAL WATERS, ESPECIALLY DURING THE MORNING AND AFTERNOON
HOURS. TROPICAL STORM JERRY IS EXPECTED TO MOVE NORTHEAST OF THE
REGION BY FRIDAY. TROPICAL STORM CONDITIONS ARE POSSIBLE BY THURSDAY
NIGHT, MOSTLY ACROSS THE EASTERN HALF OF THE REGIONAL WATERS
INCLUDING ATLANTIC AND CARIBBEAN WATERS, AND THE ANEGADA PASSAGE.
BEACH FORECAST
A MODERATE RISK OF RIP CURRENTS WILL CONTINUE TO PERSIST ACROSS
THE EXPOSED ATLANTIC BEACHES OF PUERTO RICO, CULEBRA, AND THE U.S.
VIRGIN ISLANDS THROUGH AT LEAST FRIDAY. THE RISK IS EXPECTED TO
BECOME HIGH FOR SAINT CROIX BY THE END OF THE WORKWEEK AS
TROPICAL STORM JERRY APPROACHES THE REGION. WE ENCOURAGE PEOPLE TO
STAY UPDATED FOR ANY CHANGES IN THE FORECAST FROM THE NATIONAL
HURRICANE CENTER.
SJU WATCHES/WARNINGS/ADVISORIES
PR...NONE.
VI...NONE.
AM...NONE.
MRR/GRS
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