952
FXCA62 TJSJ 020901
AFDSJU
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN JUAN PR
501 AM AST FRI MAY 2 2025
SYNOPSIS
ONCE AGAIN, 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 WAS EXTENDED
UNTIL SATURDAY MORNING DUE TO THE EXPECTED WEATHER TODAY.
CONDITIONS WILL SLIGHTLY IMPROVE ON SUNDAY, BUT THE WET AND
UNSETTLED WEATHER CONDITIONS ARE LIKELY RETURN THE NEXT WORKWEEK.
SHORT TERM...TODAY THROUGH SUNDAY
...A FLASH FLOOD WATCH REMAINS IN EFFECT FOR PUERTO RICO THROUGH
AT LEAST SATURDAY...
SHOWER AND THUNDERSTORM ACTIVITY WILL CONTINUE TO INCREASE ACROSS
THE U.S. VIRGIN ISLANDS AND THE EASTERN SECTIONS PUERTO RICO THROUGH
THE REST OF THE MORNING HOURS. PONDING OF WATER ON ROADS AND IN POOR
DRAINAGE AREAS IS EXPECTED WITH THIS ACTIVITY. THEN, JUST BEFORE
NOON AND SIMILAR TO PREVIOUS DAYS, THUNDERSTORMS ARE EXPECTED TO
DEVELOP ALONG PORTIONS OF THE CORDILLERA CENTRAL AND LAST THROUGH
THE EVENING HOURS. DUE TO ALREADY SATURATED SOILS AND ABOVE NORMAL
STREAMFLOWS FROM PREVIOUS DAYS EXCESSIVE RAINFALL AND RUNOFF, QUICK
RIVER RISES, LANDSLIDES, AND FLASH FLOODING IS LIKELY WITH THESE
THUNDERSTORMS ONCE AGAIN. WINDS WILL REMAIN FROM THE ENE BUT WITH A
PREVAILING EASTERLY COMPONENT IN THE STEERING FLOW, THEREFORE,
PORTIONS OF WESTERN PR THAT HAVE NOT RECEIVED AS MUCH RAINFALL IN
THE PAST DAYS WILL SEE AN INCREASE IN ACCUMULATIONS TODAY.
THE WET WEATHER PATTERN WILL CONTINUE THROUGH AT LEAST SATURDAY,
WITH PRECIPITABLE WATER CONTENT PEAKING AROUND 2.15 INCHES FROM THIS
AFTERNOON THROUGH SATURDAY, AND DECREASING TO NEAR 1.80 INCHES BY
SUNDAY EVENING. THIS HIGHER THAN NORMAL MOISTURE CONTENT WILL
COMBINE WITH FAVORABLE ATMOSPHERIC CONDTIONS AT THE MID-AND UPPER-
LEVELS FROM A DEVELOPING TROUGH/LOW TO OUR NORTHWEST AND PRODUCE
ISOLATED TO SCATTERED THUNDERSTORMS WITH PERIODS OF HEAVY RAINFALL
FOR THE NEXT 24-36 HOURS. 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
THROUGH THE WEEKEND. ON SUNDAY, ALTHOUGH THE OVERALL MOISTURE
CONTENT IS EXPECTED TO DECREASE, DIURNALLY INDUCED AFTERNOON
THUNDERSTORMS WILL DEVELOP ONCE AGAIN OVER THE MOUNTAIN RANGES OF
PR, PRODUCING PERIODS OF LOCALLY HEAVY RAINFALL AND TRIGGERING ONCE
AGAIN FLOOD CONCERNS OVER EXTREMELY SATURATED SOILS.
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...MONDAY THROUGH FRIDAY
NO SIGNIFICANT CHANGES WERE MADE TO THE LONG-TERM FORECAST. THE
SYNOPTIC PATTERN CONTINUES AS EXPECTED, WITH A SURFACE HIGH PRESSURE
BUILDING IN THE WESTERN ATLANTIC THAT SHOULD MOVE EASTWARD AND AN
INDUCED LOW LINGERING OVER THE CENTRAL ATLANTIC. THE MID TO
UPPER- LEVEL TROUGH HIGHLIGHTED BY THE GLOBAL MODELS FOR THE PAST
FEW DAYS IS STILL EXPECTED TO APPROACH THE CWA BY WEDNESDAY,
INCREASING INSTABILITY ALOFT. THE WIND PATTERN WILL BE VARIABLE,
AS ENE WINDS WILL REDUCE BY TUESDAY AND REMAIN LIGHT FOR THE REST
OF THE FORECAST PERIOD. REGARDING THE SHOWER ACTIVITY, THE LATEST
GLOBAL MODEL ENSEMBLES SHOWED AN INCREASE IN UNCERTAINTY, WITH
SOME MEMBERS GOING FOR A LESS AGGRESSIVE SOLUTION COMPARED TO THE
PAST FEW DAYS. HOWEVER, THEY STILL EXPECT PWAT VALUES TO REMAIN
NEAR TO ABOVE CLIMATOLOGICAL NORMALS (1.7 - 1.9 INCHES) THROUGHOUT
THE ENTIRE PERIOD. THE TEMPERATURES IN THE 500 MB SHOULD INCREASE
TO SEASONAL VALUES (AROUND -7 CELSIUS) BY MONDAY AND TUESDAY, BUT
WILL GET COLDER BY MIDWEEK (AROUND -8 CELSIUS). ADDITIONALLY,
STRONGER UPPER LEVEL WINDS SHOULD BRING VENTILATION ALOFT,
INCREASING INSTABILITY. THEREFORE, THERE'S CONFIDENCE OF
DEVELOPMENT OF THUNDERSTORMS DURING THE AFTERNOONS EACH DAY.
WINDWARD SECTIONS CAN EXPECT LIGHT TO MODERATE SHOWERS
MOVING OCCASIONALLY DURING THE NIGHT AND THE MORNING HOURS, WHILE
THE DEEP AFTERNOON CONVECTION WILL CONCENTRATE ON THE INTERIOR
PORTIONS OF PUERTO RICO. WITH THE RECENT HEAVY RAINFALL, ABOVE-
NORMAL STREAMFLOWS, SATURATED SOILS, AND THE EXPECTED CONDITIONS,
THE FLOOD THREAT REMAINS ELEVATED MAINLY OVER THE AFOREMENTIONED
AREAS. THERE SHOULD BE AN IMPROVEMENT IN THE WEATHER CONDITIONS BY
FRIDAY, AS A DRIER AIR MASS FILTERS INTO THE REGION, PROMOTING
STABLE CONDITIONS ACROSS THE LOCAL ISLANDS.
SEASONAL TEMPERATURES SHOULD PREVAIL FOR THE REST OF THE FORECAST
PERIOD, WITH THE HEAT RISK REMAINING LOW ACROSS THE CWA.
AVIATION
(06Z TAFS)
SHRA AND ISO TSTMS INCREASING FROM THE ATLANTIC AND EASTERN WATERS
OF THE ISLANDS COULD MOVE ACROSS THE USVI/EASTERN PR TERMINALS THRU
THE REST OF THE MORNING HOURS. THIS CAN LEAD TO BRIEF MVFR CIGS. MTN
TOPS OBSCD AND BKN/OVC LYRS BTW FL030-250 EXPECTED AFT 02/16Z, WHEN
SHRA/TSRA DEVELOPS TILL AT LEAST 02/23Z OVER THE MOUNTAINS AND
WESTERN PR. STEERING WINDS WILL HAVE A MORE EASTERLY COMPONENT
TODAY, BUT IN GENERAL ENE WINDS EXPECTED AT THE SFC AND INCREASING
BTW 12-16 KT WITH STRONGER GUSTS AFT 02/14. STRONGER SUSTAINED WINDS
BTW 16-21 KT ARE EXPECTED FM 02/22Z-03/06Z ACROSS THE ATLANTIC AND
EASTERN WATERS BTW PR AND THE USVI.
MARINE
A SURFACE HIGH PRESSURE BUILDING ACROSS 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 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 IS STILL EXPECTED TO GRADUALLY DECREASE THIS
WEEKEND INTO EARLY NEXT WEEK.
SJU WATCHES/WARNINGS/ADVISORIES
PR...FLOOD WATCH THROUGH SATURDAY MORNING FOR PRZ001>013.
VI...NONE.
AM...NONE.
SHORT TERM/AVIATION...DS
LONG TERM/MARINE....MNG
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