356
FXCA62 TJSJ 251237
AFDSJU
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN JUAN PR
837 AM AST MON MAY 25 2026
UPDATE
RECENT ASCAT DATA INDICATED A BROAD AREA OF 20-25 KNOTS WINDS
SURROUNDING THE ISLANDS. OBSERVED WIND GUSTS ACROSS THE ISLANDS
SINCE MIDNIGHT WERE BETWEEN 22-31 MPH. STRONG WINDS AND ROUGH
SEAS WILL CONTINUE THROUGH TUESDAY. THEREFORE, THE SMALL CRAFT
ADVISORY AND RIP CURRENT STATEMENT WERE EXTENDED THROUGH LATE
TUESDAY.
PREV DISCUSSION
/ISSUED 346 AM AST MON MAY 25 2026/
..NEW SHORT TERM, LONG TERM, AVIATION, MARINE, BEACH FORECAST, FIRE WEATHER...
KEY MESSAGES...
ISSUED AT 301 AM AST MON MAY 25 2026
* BREEZY TO WINDY EASTERLY CONDITIONS ARE EXPECTED TODAY. OUTDOOR
ITEMS COULD BE BLOWN AROUND OR DAMAGED. THEREFORE, A WIND
ADVISORY IS IN EFFECT THROUGH THIS EVENING.
* HAZARDOUS MARINE AND COASTAL CONDITIONS WILL CONTINUE THROUGH AT
LEAST TOMORROW TUESDAY. SMALL CRAFT ADVISORIES REMAIN IN EFFECT
FOR MOST LOCAL WATERS, AND A HIGH RISK OF RIP CURRENT IS
EXPECTED FOR MANY NORTHERN, EASTERN, AND SOUTHEASTERN BEACHES OF
PUERTO RICO AND THE U.S. VIRGIN ISLANDS.
* WARM TO HOT CONDITIONS WILL PERSIST THROUGH MUCH OF THE WEEK
ACROSS THE ISLANDS, WITH HOTTER CONDITIONS EXPECTED BY THE END OF
THE WEEK. HEAT INDICES ARE EXPECTED TO EXCEED 100 DEGREES ACROSS
URBAN AND COASTAL AREAS OF PUERTO RICO AND THE U.S. VIRGIN
ISLANDS, WITH A MODERATE TO LOCALLY ELEVATED RISK OF HEAT-RELATED
IMPACTS.
* AFTERNOON SHOWERS AND VERY ISOLATED THUNDERSTORMS COULD STILL
IMPACT WESTERN PORTIONS OF PUERTO RICO DESPITE THE ARRIVAL OF A
DRIER AIRMASS OVER THE REGION TODAY. UPTICK OF PASSING SHOWERS
ACROSS WINDWARD COASTAL AREAS AND SMALLER ISLANDS TONIGHT.
* MINOR TO MODERATE CONCENTRATIONS OF SAHARAN DUST ARE FORECAST TO
ARRIVE BY MIDWEEK AND PERSIST INTO LATE WEEK, RESULTING IN HAZY
SKIES AND POSSIBLE REDUCTIONS IN AIR QUALITY AND VISIBILITY,
ESPECIALLY FOR SENSITIVE GROUPS.
SHORT TERM(TODAY THROUGH WEDNESDAY)...
ISSUED AT 301 AM AST MON MAY 25 2026
BREEZY TO WINDY EASTERLY CONDITIONS WILL CONTINUE TODAY AS SURFACE
HIGH PRESSURE MAINTAINS A TIGHT LOCAL PRESSURE GRADIENT ACROSS THE
NORTHEASTERN CARIBBEAN. GLOBAL MODELS SUGGEST THAT 925 MB WINDS WILL
REMAIN WELL ABOVE NORMAL TODAY, SUPPORTING GUSTY CONDITIONS AT THE
SURFACE, ESPECIALLY ACROSS COASTAL AREAS, HIGHER ELEVATIONS, AND
EXPOSED LOCATIONS. OUTDOOR ITEMS COULD BE BLOWN AROUND OR DAMAGED,
AND TREE LIMBS COULD BE BLOWN DOWN. THEREFORE, A WIND ADVISORY IS IN
EFFECT THROUGH THIS EVENING.
A BRIEF DRYING TREND IS EXPECTED TODAY AS PRECIPITABLE WATER VALUES
DROP SHARPLY TO NEAR 1.3 INCHES, WHICH IS BELOW NORMAL FOR LATE MAY.
LOW- TO MID-LEVEL MOISTURE WILL ALSO DECREASE, WITH 850-700 MB
RELATIVE HUMIDITY VALUES FALLING INTO THE 30 TO 40 PERCENT RANGE AT
TIMES. DESPITE THE ARRIVAL OF THIS DRIER AIR MASS, SUFFICIENT LOW-
LEVEL MOISTURE AND LOCAL EFFECTS WILL STILL SUPPORT AFTERNOON
SHOWERS AND VERY ISOLATED THUNDERSTORMS ACROSS WESTERN PORTIONS OF
PUERTO RICO.
BY LATE TONIGHT INTO TUESDAY, AND CONTINUING INTO WEDNESDAY,
MOISTURE WILL INCREASE AGAIN AS TROPICAL MOISTURE ASSOCIATED WITH A
TROPICAL WAVE SURGE AND AN EASTERLY PERTURBATION MOVES INTO THE
REGION. MODEL GUIDANCE INDICATES PRECIPITABLE WATER VALUES RISING
BACK TO NEAR OR ABOVE NORMAL LEVELS, GENERALLY AROUND 2.0 INCHES OR
EVEN SLIGHTLY HIGHER, WITH MID-LEVEL RELATIVE HUMIDITY INCREASING AS
WELL. THIS WILL SUPPORT A WETTER AND MORE UNSTABLE PATTERN.
ALTHOUGH WIDESPREAD SIGNIFICANT RAINFALL IS NOT ANTICIPATED AT THIS
TIME, THE INCREASE IN MOISTURE AND INSTABILITY ON TUESDAY AND
WEDNESDAY WILL ELEVATE THE RISK FOR URBAN AND SMALL-STREAM FLOODING.
THE HIGHEST RAINFALL POTENTIAL SHOULD FOCUS ACROSS WESTERN AND
INTERIOR PUERTO RICO DURING THE AFTERNOONS, AS SEA BREEZE
CONVERGENCE AND LOCAL EFFECTS COMBINE WITH POTENTIAL THUNDERSTORM
ACTIVITY. EASTERN PUERTO RICO, THE U.S. VIRGIN ISLANDS, AND THE
SMALLER ISLANDS WILL SEE PERIODIC PASSING SHOWERS EMBEDDED IN THE
EASTERLY TRADES.
WARM TO HOT CONDITIONS WILL PERSIST THROUGH THE PERIOD, WITH THE
HOTTEST CONDITIONS EXPECTED BY MIDWEEK. HEAT INDICES ARE EXPECTED TO
EXCEED 100 DEGREES ACROSS URBAN AND COASTAL AREAS OF PUERTO RICO AND
THE U.S. VIRGIN ISLANDS, RESULTING IN A MODERATE TO LOCALLY ELEVATED
RISK OF HEAT-RELATED IMPACTS. IN ADDITION, MINOR TO LOCALLY MODERATE
CONCENTRATIONS OF SAHARAN DUST ARE FORECAST TO ARRIVE BY MIDWEEK.
THIS MAY RESULT IN HAZY SKIES AND POSSIBLE REDUCTIONS IN AIR QUALITY
AND VISIBILITY, ESPECIALLY FOR SENSITIVE GROUPS.
LONG TERM(THURSDAY THROUGH MONDAY)...
ISSUED AT 301 AM AST MON MAY 25 2026
THE LONG-TERM FORECAST REMAINS ON TRACK. AT THE SURFACE, LINGERING
MOISTURE ASSOCIATED WITH A PREVIOUS TROPICAL WAVE WILL REMAIN ACROSS
THE FORECAST AREA, WITH PWAT VALUES AROUND 2.10 INCHES. THIS PATTERN
WILL PROMOTE A WETTER AND "MUGGY" WEATHER PATTERN, SUPPORTING SHOWER
DEVELOPMENT ACROSS THE ISLANDS WITH PERIODS OF MODERATE TO HEAVY
RAINFALL. A BROAD HIGH PRESSURE EXTENDING INTO THE CENTRAL ATLANTIC
WILL MAINTAIN EAST-SOUTHEASTERLY WINDS, PROMOTING WARM CONDITIONS
ACROSS NORTHERN AND WESTERN PUERTO RICO. ADDITIONALLY, THE NASA
GODDARD EARTH OBSERVING SYSTEM MODEL CONTINUES TO INDICATE A
SIGNIFICANT PULSE OF SAHARAN AIR LAYER MOVING INTO THE REGION
THROUGH THE DAY. THIS INCREASE IN SUSPENDED DUST PARTICLES WILL
RESULT IN HAZY SKIES AND WARMER DAYTIME TEMPERATURES. STABLE
CONDITIONS AT THE MID-LEVELS DUE TO A STRENGTHENING RIDGE ALOFT MAY
GRADUALLY LIMIT WIDESPREAD THUNDERSTORM ACTIVITY, ALTHOUGH LOCAL
EFFECTS AND AVAILABLE MOISTURE WILL STILL SUPPORT AFTERNOON
CONVECTION ACROSS THE INTERIOR AND NORTHWESTERN PUERTO RICO. URBAN
AND SMALL-STREAM FLOODING, PONDING OF WATER ON ROADS, ISOLATED
LIGHTNING STRIKES, AND GUSTY WINDS WILL REMAIN POSSIBLE WITH THE
STRONGEST SHOWERS. HEAT INDICES MAY ALSO REACH ELEVATED LEVELS
ACROSS URBAN AND COASTAL AREAS DUE TO THE COMBINATION OF WARM
TEMPERATURES AND HIGH HUMIDITY.
FROM FRIDAY THROUGH SUNDAY, THE AVAILABLE MOISTURE IS FORECAST TO
MIGRATE NORTHWARD AS A DRIER AIR MASS FILTERS INTO THE NORTHEASTERN
CARIBBEAN, LOWERING PWAT VALUES GENERALLY BETWEEN 1.60 AND 1.80
INCHES. SURFACE WINDS WILL PERSIST FROM THE SOUTHEAST AS THE
ATLANTIC HIGH PRESSURE REMAINS THE DOMINANT WEATHER FEATURE ACROSS
THE REGION. THIS PATTERN, COMBINED WITH HIGHER 925 MB TEMPERATURES
AND INCREASING SAHARAN DUST CONCENTRATIONS, WILL PROMOTE A NOTABLE
WARMING TREND THROUGH THE WEEKEND. UNDER PERIODS OF LIMITED CLOUD
COVERAGE, HEAT INDICES MAY RISE BETWEEN 108 AND 111 DEGREES ACROSS
NORTHERN, WESTERN, AND URBAN COASTAL SECTIONS OF PUERTO RICO. HAZY
SKIES AND POOR AIR QUALITY MAY ALSO AFFECT SENSITIVE GROUPS,
INCLUDING INDIVIDUALS WITH RESPIRATORY CONDITIONS AND ALLERGIES.
ALTHOUGH A DRIER AND MORE STABLE PATTERN IS EXPECTED OVERALL, LOCAL
EFFECTS AND DAYTIME HEATING WILL CONTINUE TO TRIGGER AFTERNOON
CONVECTION EACH DAY, MAINLY ACROSS THE NORTHWESTERN QUADRANT OF
PUERTO RICO. ON SUNDAY, A SLIGHT SURGE OF MOISTURE MAY INCREASE
SHOWER DEVELOPMENT ONCE AGAIN, RESULTING IN MORE ACTIVE AFTERNOON
CONVECTION ACROSS PORTIONS OF WESTERN PUERTO RICO. ON MONDAY, BOTH
THE GLOBAL GFS AND ECMWF MODELS SUGGEST A SIGNIFICANT DRYING TREND,
WITH PRECIPITABLE WATER VALUES DROPPING TO AROUND 1.2 INCHES. THIS
DRASTIC CHANGE WILL RESULT FROM A LARGE PULSE OF DRIER AIR
ASSOCIATED WITH A SAHARAN AIR LAYER INTRUSION, ENOUGH TO PROMOTE
WIDESPREAD HAZY SKIES AND A CONTINUED WARM TREND ACROSS THE
REGION.
AVIATION...
(06Z TAFS)
ISSUED AT 301 AM AST MON MAY 25 2026
MAINLY VFR CONDS EXPECTED TO PREVAIL THROUGH THE FCST PERIOD. BRIEF
VCSH WILL REMAIN POSSIBLE ACROSS TJSJ/TIST/TISX THRU THE MORNING
HRS, WITH AFTERNOON SHRA/ISOL TSRA POSSIBLE NEAR TJBQ BTW 18-22Z.
THE 25/00Z TJSJ SOUNDING INDICATED E WINDS UP TO 24 KT BLO FL060.
SFC WINDS GENERALLY E AT 08-15 KT EARLY, INCREASING AFT 14Z TO 20-24
KT WITH GUSTS AROUND 30-33 KT. WINDS DIMINISH SLIGHTLY AFTER 23Z BUT
REMAIN BREEZY, WITH VCSH POSSIBLE AGAIN ACROSS WINDWARD TERMINALS.
MARINE...
ISSUED AT 301 AM AST MON MAY 25 2026
SMALL CRAFT ADVISORIES REMAIN IN EFFECT FOR THE OFFSHORE WATERS AND
LOCAL PASSAGES THROUGH TUESDAY MORNING AS MODERATE TO LOCALLY STRONG
EASTERLY WINDS CONTINUE TO GENERATE CHOPPY TO ROUGH SEAS OF UP TO 7
FEET. THESE CONDITIONS WILL PERSIST THROUGH AT LEAST MIDWEEK AS
STRONG HIGH PRESSURE OVER THE CENTRAL ATLANTIC MAINTAINS A TIGHT
PRESSURE GRADIENT ACROSS THE NORTHEASTERN CARIBBEAN. IN ADDITION,
ISOLATED AFTERNOON THUNDERSTORMS NEAR THE WESTERN COASTAL WATERS OF
PUERTO RICO MAY PRODUCE LOCALLY HIGHER WINDS AND SEAS.
BEACH FORECAST...
ISSUED AT 301 AM AST MON MAY 25 2026
A HIGH RISK OF RIP CURRENTS, MEANING LIFE-THREATENING RIP CURRENTS
ARE LIKELY IN THE SURF ZONE, WILL CONTINUE THROUGH LATE TONIGHT FOR
THE NORTHERN, EASTERN, NORTHEASTERN, AND SOUTHEASTERN BEACHES OF
PUERTO RICO, AS WELL AS VIEQUES, CULEBRA, AND THE U.S. VIRGIN
ISLANDS. A MODERATE RISK OF RIP CURRENTS, MEANING LIFE-THREATENING
RIP CURRENTS ARE POSSIBLE IN THE SURF ZONE, WILL PERSIST ACROSS THE
REMAINING LOCAL BEACHES. THE RISK IS EXPECTED TO INCREASE AGAIN
ACROSS MANY EXPOSED BEACHES MONDAY INTO TUESDAY AS EASTERLY WINDS
STRENGTHEN AND THE ATLANTIC PRESSURE GRADIENT TIGHTENS.
BEACHGOERS SHOULD HEED THE ADVICE OF LOCAL OFFICIALS AND BEACH
SAFETY PERSONNEL. AFTERNOON THUNDERSTORMS ARE ALSO POSSIBLE EACH DAY
ACROSS WESTERN PUERTO RICO AND MAY PRODUCE DANGEROUS LIGHTNING. FOR
ADDITIONAL INFORMATION AND LOCATION-SPECIFIC RIP CURRENT FORECASTS,
VISIT WEATHER.GOV/BEACH/SJU.
FIRE WEATHER...
ISSUED AT 301 AM AST MON MAY 25 2026
LITTLE TO NO RAINFALL IS ANTICIPATED ACROSS THE SOUTHERN SECTIONS OF
PUERTO RICO TODAY. DRIER AIR IS ALSO EXPECTED TO FILTER INTO THE
REGION, ALLOWING RELATIVE HUMIDITY VALUES TO DROP INTO THE UPPER 40S
TO LOW 50S. WIND SPEEDS MAY REACH AROUND 16 TO 25 MPH, WITH HIGHER
GUSTS. FURTHERMORE, A WIND ADVISORY IS IN EFFECT THROUGH THIS
EVENING. KBDI VALUES IN CABO ROJO REMAIN ABOVE CRITICAL FIRE WEATHER
THRESHOLDS. ADDITIONALLY, THE 7-DAY PERCENT OF NORMAL RAINFALL
ACROSS THE SOUTHERN COASTAL PLAINS IS BELOW 25%, WITH SOME LOCATIONS
EVEN BELOW 5%. THEREFORE, CONDITIONS WILL BE FAVORABLE FOR THE
SPREAD OF WILDFIRES ALONG THE SOUTHERN COASTAL PLAINS OF PUERTO
RICO. A FIRE DANGER STATEMENT (RFDSJU) HAS BEEN ISSUED.
SJU WATCHES/WARNINGS/ADVISORIES
PR...HIGH RIP CURRENT RISK THROUGH TUESDAY AFTERNOON FOR PRZ001>003-
005-008-012-013.
WIND ADVISORY UNTIL 8 PM AST THIS EVENING FOR PRZ001>013.
VI...HIGH RIP CURRENT RISK THROUGH TUESDAY AFTERNOON FOR VIZ001-002.
WIND ADVISORY UNTIL 8 PM AST THIS EVENING FOR VIZ001-002.
AM...SMALL CRAFT ADVISORY UNTIL MIDNIGHT AST TUESDAY NIGHT FOR AMZ711-
712.
SMALL CRAFT ADVISORY UNTIL NOON AST TUESDAY FOR AMZ716-723-726-
733-741.
UPDATE...DSR
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