160
FXCA62 TJSJ 010904
AFDSJU
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN JUAN PR
504 AM AST THU MAY 1 2025
SYNOPSIS
UNSETTLED WEATHER IS EXPECTED OVER THE NEXT SEVERAL DAYS DUE TO A
COMBINATION OF ABUNDANT TROPICAL MOISTURE AND A SERIES OF UPPER-
LEVEL TROUGHS. THE FLOOD WATCH REMAINS IN EFFECT FOR PUERTO RICO
UNTIL FRIDAY MORNING. THE COVERAGE AND INTENSITY OF THESE SHOWERS
ARE EXPECTED TO DECREASE SOMEWHAT DURING THE UPCOMING WEEKEND. WET
AND UNSETTLED WEATHER CONDITIONS MAY RETURN NEXT WEEK (AROUND
WEDNESDAY).
SHORT TERM...TODAY THROUGH SATURDAY
A FLASH FLOOD WATCH REMAINS IN EFFECT FOR PUERTO RICO UNTIL AT LEAST
FRIDAY MORNING. SHOWERS AND THUNDERSTORMS WILL DEVELOP ONCE AGAIN
OVER THE SAME AREAS IN THE AFTERNOON HOURS AND COULD LINGER INTO THE
EVENING HOURS. SATURATED SOILS AND ABOVE NORMAL STREAMFLOWS FROM
PREVIOUS DAYS EXCESSIVE RAINFALL CONTINUES ACROSS PORTIONS OF THE
CORDILLERA CENTRAL AND EASTERN PR. ANY ADDITIONAL HEAVY RAINFALL
ACROSS THESE AREAS WILL POSE AN ELEVATED TO SIGNIFICANT THREAT FOR
FLASH FLOODS AND LANDSLIDES.
A DEEP LAYERED LOW OVER THE CENTRAL ATLANTIC AND A RIDGE EAST OF THE
WINDWARD ISLANDS WILL CONTINUE TO PROMOTE MOISTURE POOLING ACROSS
THE NORTHEASTERN CARIBBEAN THROUGHOUT THE REMINDER OF THE FORECAST
PERIOD. IN ADDITION, SHOWER AND THUNDERSTORM ACTIVITY WILL CONTINUE
ACROSS THE ISLANDS ON FRIDAY AND SATURDAY, MAINLY IN DIURNAL
ACTIVITY ENHANCED BY ANOTHER MID-TO UPPER-LEVEL TROUGH MOVING FROM
THE NORTHWEST. DUE TO THE UNSTABLE CONDITIONS ALOFT AND ABUNDANT
TROPICAL MOISTURE OVER THE AREA THE RISK FOR EXCESSIVE RAINFALL WILL
REMAIN ELEVATED EACH DAY, PARTICULARLY OVER CENTRAL PR. ACROSS THE
USVI, MOISTURE CONTENT WILL PEAK BETWEEN THE AFTERNOON/EVENING HOURS
TODAY AND ON SATURDAY. HOWEVER, THUNDERSTORMS WERE DEVELOPING JUST
WEST AND SOUTH OF ST. CROIX EARLIER THIS MORNING, AND MOSTLY LIGHT
TO MODERATE RAINFALL WAS OBSERVED OVER LAND AREAS.
RESIDENTS AND VISITORS ARE URGE TO MONITOR THE WEATHER CONDITIONS
AND REMAIN VIGILANT TO TAKE NECESSARY ACTION TO PROTECT LIFE AND
PROPERTY FROM THE EXPECTED FLOODING IMPACTS. FOR MORE INFORMATION
PLEASE REFER TO THE LATEST UPDATES FROM THE FLASH FLOOD WATCH
(FFASJU).
HTTPS://FORECAST.WEATHER.GOV/WWAMAP/WWATXTGET.PHP?CWA=SJU&WWA=FLOOD%2
0WATCH
LONG TERM...SUNDAY THROUGH THURSDAY
THE FORECAST FOR THE BEGINNING OF THE WEEK REMAINS ON TRACK. WINDS
SHOULD REMAIN FROM THE SOUTHEAST, DUE TO THE HIGH SURFACE PRESSURE
BUILDING IN THE WESTERN ATLANTIC AND THE DEEP LAYERED TROUGH
NORTHEAST OF THE CWA. BASED ON THE LATEST MODEL GUIDANCE, PWAT
VALUES WILL REMAIN ABOVE NORMAL (1.8 - 2.0 INCHES) DUE TO HIGH
LOW TO MID-LEVEL MOISTURE CONTENT. THE RIDGING IN THE MID TO HIGH
LEVELS IS STILL EXPECTED, FILTERING DRIER AIR. HOWEVER, THE 500 MB
TEMPERATURES SHOULD CONTINUE BETWEEN -7 AND -8 CELSIUS, COLDER
BASED ON CLIMATOLOGY. ADDITIONALLY, STRONG UPPER-LEVEL WINDS COULD
BRING VENTILATION ALOFT AND CONSEQUENTLY INCREASE INSTABILITY.
THE COMBINATION OF AVAILABLE MOISTURE, LOCAL EFFECTS, SLOWING
WINDS, AND DAYTIME HEATING WILL BRING LIGHT TO MODERATE SHOWERS
AND ISOLATED THUNDERSTORMS DURING THE AFTERNOON, MAINLY OVER
INTERIOR PUERTO RICO. A TRANSITION TO A MORE UNSETTLED AND WET
PATTERN BY THE SECOND PART OF THE WEEK IS STILL EXPECTED, WITH
ANOTHER DEEP MID TO UPPER LEVEL TROUGH APPROACHING THE LOCAL AREA
BY TUESDAY INTO WEDNESDAY. THE LATEST MODEL GUIDANCE SOLUTION SHOW
A DRIER AIR MASS FILTERING INTO THE REGION. HOWEVER, THE
AVAILABLE MOISTURE REMAINS ABOVE CLIMATOLOGICAL NORMALS. GLOBAL
MODELS STRONGLY SUGGEST WELL ABOVE NORMAL MOISTURE CONTENT POOLING
INTO THE REGION BEGINNING ON WEDNESDAY. ADDITIONALLY, EXTREME
FORECAST INDEXES (EFI) CONTINUE HIGHLIGHTING THE SIGNIFICANT
WEATHER CLOSER TO THE REGION DURING THAT PERIOD. THERE'S
CONFIDENCE THAT THE ABOVE NORMAL MOISTURE AND MID TO UPPER- LEVEL
DYNAMICS SHOULD BE ENOUGH TO ENHANCE DEEP AFTERNOON CONVECTION
FOR THE SECOND PART OF THE NEXT WORKWEEK.
DUE TO SATURATED SOILS, ABOVE NORMAL STREAMFLOWS, AND THE
EXPECTED WEATHER, THE FLOOD THREAT WILL REMAIN ELEVATED EACH DAY,
MAINLY FOR THE INTERIOR OF PUERTO RICO.
THE TENDENCY OF OBSERVING NEAR ABOVE-NORMAL TEMPERATURES IN THE
DAYTIME CONTINUES, BUT THE HEAT RISK WILL REMAIN LOW FOR THE LONG
TERM FORECAST.
AVIATION
(06Z TAFS)
SHRA/TSRA OVER THE CARIBBEAN WATERS MAY CAUSE TEMPO MVFR CONDS
ACROSS THE USVI TERMINALS DURING THE EARLY MORNING HOURS. THE SEA
BREEZE CONVERGENCE WILL CAUSE +SHRA/TSRA DEVELOPMENT AROUND NOON
OVER THE CENTRAL PORTIONS OF THE ISLANDS, AND MVFR TO BRIEF IFR
CONDS ARE POSSIBLE ONCE AGAIN ALONG THE SOUTHERN TERMINALS OF THE
ISLANDS. MTN TOPS OBSCD AND BKN/OVC LYRS BTW FL040-200 EXPECTED.
WINDS WILL REMAIN ENE UP TO 13 KT WITH SEA BREEZE VARIATIONS ALONG
THE WESTERN AND SOUTHERN COASTAL AREAS, AND STRONGER GUSTS NEAR
TSTMS.
MARINE
A SURFACE HIGH PRESSURE BUILDING IN THE WESTERN ATLANTIC AND A
DEEP LAYERED TROUGH NORTHEAST OF THE REGION WILL CONTINUE
PROMOTING LIGHT TO MODERATE EAST- NORTHEAST TO NORTHEAST WINDS FOR
THE NEXT FEW DAYS. SHOWERS AND THUNDERSTORMS ARE EXPECTED TO
DEVELOP ACROSS THE LOCAL WATERS, PRODUCING LOCALLY HIGHER WINDS
AND SEAS. SMALL CRAFT SHOULD EXERCISE CAUTION AND STAY WEATHER
ALERT.
BEACH FORECAST
THE MODERATE RISK OF RIP CURRENTS WILL CONTINUE FOR THE BEACHES IN
NORTHERN PUERTO RICO, CULEBRA, AND NOW FOR ST. THOMAS AND ST. JOHN
IN THE U.S. VIRGIN ISLANDS. BEACHGOERS MUST EXERCISE CAUTION DUE
TO POSSIBLE LIFE- THREATENING RIP CURRENTS ALONG THE SURF ZONE AND
STAY WEATHER ALERT.
THE RIP CURRENT RISK WILL BE LOW FOR THE LOCAL ISLANDS BY THE END
OF THE WEEKEND.
SJU WATCHES/WARNINGS/ADVISORIES
PR...FLOOD WATCH THROUGH FRIDAY MORNING FOR PRZ001>013.
VI...NONE.
AM...NONE.
SHORT TERM/AVIATION...DS
LONG TERM/MARINE....MNG
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