404
FXCA62 TJSJ 030857
AFDSJU
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN JUAN PR
457 AM AST SAT MAY 3 2025
SYNOPSIS
UNSTABLE AND WET WEATHER CONDITIONS ARE ANTICIPATED TO CONTINUE
THROUGH NEXT WEEK DUE TO A COMBINATION OF ABUNDANT TROPICAL
MOISTURE AND A SERIES OF UPPER-LEVEL TROUGHS MOVING OVER THE
REGION. THE FLOOD WATCH WAS EXTENDED THROUGH THIS EVENING DUE TO
CONTINUOUS RAINFALL ACTIVITY RESULTING IN HAZARDOUS WEATHER
CONDITIONS ACROSS PUERTO RICO TODAY. UNSETTLED WEATHER CONDITIONS
ARE LIKELY TO PERSIST THROUGH MID-WEEK.
SHORT TERM...TODAY THROUGH MONDAY
...A FLASH FLOOD WATCH REMAINS IN EFFECT FOR PUERTO RICO THROUGH
THIS EVENING...
MOSTLY CLOUDY SKIES PREVAILED OVERNIGHT AS STRONG THUNDERSTORMS
DEVELOPED ALONG THE NORTH-CENTRAL TO EASTERN SECTIONS OF PUERTO RICO
AND ACROSS THE ATLANTIC WATERS. ADDITIONAL SHOWERS WERE INCREASING
IN THE PAST FEW HOURS ACROSS THE CARIBBEAN WATERS AND THE EASTERN
INTERIOR PORTIONS OF PUERTO RICO. A RAIN GAUGE IN VEGA BAJA REPORTED
OVER 6 INCHES OF RAIN IN LESS THAN 4 HOURS. RIVER FLOODING WAS
OBSERVED IN RIO GRANDE, NAGUABO, AND LUQUILLO, AND MINOR RIVER
FLOODING ALONG RIO GUANAJIBO DUE TO YESTERDAY'S RAINFALL.
THE CURRENT WET WEATHER PATTERN IS EXPECTED TO CONTINUE UNTIL LATE
TONIGHT. PRECIPITABLE WATER VALUES WILL REMAIN ABOVE NORMAL LEVELS,
BETWEEN 2.15 AND 2.20 INCHES TODAY, BEFORE GRADUALLY DECREASING TO
AROUND 1.80 INCHES BY SUNDAY EVENING. THIS ABOVE-NORMAL MOISTURE,
COMBINED WITH FAVORABLE MID- TO UPPER-LEVEL CONDITIONS FROM LOW
PRESSURE TO OUR NORTH, WILL CONTINUE TO PRODUCE ISOLATED TO
SCATTERED THUNDERSTORMS WITH PERIODS OF HEAVY RAINFALL THROUGH AT
LEAST TONIGHT. THEREFORE, THE FLASH FLOOD WATCH WAS EXTENDED THROUGH
AT LEAST 8 PM AST TONIGHT. THE POTENTIAL FOR LANDSLIDES WILL
CONTINUE ALONG STEEP TERRAIN DUE TO SATURATED SOILS.
ALTHOUGH THE OVERALL MOISTURE CONTENT IS ANTICIPATED TO DECREASE ON
SUNDAY AND MONDAY, AFTERNOON THUNDERSTORMS TRIGGERED BY DAYTIME
HEATING WILL LIKELY DEVELOP AGAIN, MAINLY ALONG PORTIONS OF THE
CORDILLERA CENTRAL AND DOWNWIND FROM THE EL YUNQUE AREA. THESE
STORMS MAY BRING LOCALIZED HEAVY RAINFALL AND HEIGHTEN FLOOD
CONCERNS DUE TO EXTREMELY SATURATED SOILS. RESIDENTS AND VISITORS
ARE STRONGLY ENCOURAGED TO MONITOR WEATHER CONDITIONS AND BE
PREPARED TO TAKE PROTECTIVE MEASURES AGAINST POTENTIAL FLOODING
IMPACTS FOR THE REST OF THE WEEKEND, AS WATERFALLS, CREEKS, AND
SMALL STREAMS WILL REACT QUICKLY TO ANY BRIEF PERIOD OF HEAVY
RAINFALL UPSTREAM.
FOR THE ADDITIONAL INFORMATION AND UPDATES, PLEASE REFER TO: THE
FLASH FLOOD WATCH (FFASJU), HAZARDOUS WEATHER OUTLOOK (HWOSJU),
GRAPHICAL HAZARDOUS WEATHER OUTLOOK
(HTTPS://WWW.WEATHER.GOV/ERH/GHWO?WFO=SJU)
LONG TERM...TUESDAY THROUGH SATURDAY
A DEEP LAYERD LOW PRESSURE NORTH OF THE AREA AND A SERIES OF
SURFACE INDUCED TROUGHS WILL PROMOTE A EAST TO NORTHEAST WIND FLOW
FOR THE FIRST HALF OF THE PERIOD. THEN, WINDS ARE EXPECTED TO
BECOME FROM THE SOUTHEAST BY THE END OF THE WORKWEEK AS THE LOW
PRESSURE SHIFTS TOWARDS THE WEST. ABUNDANT LOW-LEVEL MOISTURE WILL
PREDOMINATE OVER THE LONG TERM- PERIOD WITH PRECIPITABLE WATER
VALUES BETWEEN 1.60 TO 1.75 INCHES. DURING THIS PERIOD THE 500 MB
TEMPERATURES WILL DROP INTO THE -7 TO -9 DEGREES CELSIUS,
SUGGESTING THE POTENTIAL TO SUPPORT CONVECTIVE ACTIVITY ACROSS THE
REGION. THROUGHOUT THE WEEK, INSTABILITY WILL PERSIST AS THE LOW
PRESSURE AND THE INDUCED SURFACE TROUGH PATTERN PREVAIL IN THE
REGION. THEREFORE, THERE IS AN INCREASED POTENTIAL TO OBSERVE
AFTERNOON CONVECTIVE ACTIVITY ALONG PORTIONS OF THE INTERIOR AND
WESTERN PUERTO RICO EACH DAY. WITH THE RAINFALL EVENTS FROM
PREVIOUS DAYS, ABOVE- NORMAL STREAMFLOWS AND SATURATED SOILS, THE
FLOOD THREAT REMAINS ELEVATED. THE LATEST MODEL GUIDANCES ARE
SUGGESTING A CHANGE IN THE WEATHER PATTERN BY THE END OF THE WEEK
INTO THE WEEKEND WITH THE ENTRANCE OF DRIER AIR INTO THE AREA.
SEASONAL TEMPERATURES ARE ANTICIPATED TO PREVAIL FOR THE REST OF
THE FORECAST PERIOD, WITH THE HEAT RISK REMAINING LOW.
AVIATION
SHRA/TSRA WILL CONTINUE ACROSS THE LOCAL AREA TODAY. TEMPO MVFR TO
BRIEF IFR CONDS ARE POSSIBLE ACROSS ALL TERMINALS TODAY, DURING THE
DAY PARTICULARLY ACROSS PR, AND IN THE LATE AFTERNOON/EVENING HOURS
IN AND AROUND THE USVI TERMINALS. MTN TOPS OBSCD EXPECTED TO
CONTINUE THRU 04/00Z. EAST WINDS 10-15 KT WITH STRONGER GUSTS AND
SEA BREEZE VARIATIONS AFT 03/13Z.
MARINE
A SURFACE HIGH PRESSURE BUILDING ACROSS THE WESTERN ATLANTIC AND A
DEEP LAYERED TROUGH NORTHEAST OF THE REGION WILL PROMOTE LIGHT TO
MODERATE EAST 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
THERE IS A MODERATE RISK OF RIP CURRENTS FOR THE EXPOSED BEACHES
OF NORTHERN PUERTO RICO, CULEBRA, AND 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 IS STILL EXPECTED TO GRADUALLY DECREASE BY EARLY NEXT
WEEK.
SJU WATCHES/WARNINGS/ADVISORIES
PR...FLOOD WATCH THROUGH THIS EVENING FOR PRZ001>013.
VI...NONE.
AM...NONE.
DSR/GRS
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