502
FXCA62 TJSJ 260713
AFDSJU
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN JUAN PR
313 AM AST WED AUG 26 2026
...NEW SHORT TERM, LONG TERM, AVIATION, MARINE, BEACH FORECAST, FIRE WEATHER...
KEY MESSAGES
UPDATED AT 303 AM AST WED AUG 26 2026
* DANGEROUS HEAT CONTINUES: EXTREME HEAT CONDITIONS ARE EXPECTED
TODAY IN PR AND THE USVI, WITH ELEVATED TO LOCALLY SIGNIFICANT
HEAT RISKS CONTINUING THROUGH THE REMAINDER OF THE WEEK.
* SAHARAN DUST TODAY: MODERATE SAHARAN DUST CONCENTRATIONS WILL
MAINTAIN HAZY SKIES AND MAY REDUCE AIR QUALITY BEFORE GRADUALLY
DECREASING TONIGHT INTO THURSDAY.
* LIMITED FLOODING RISK: AFTERNOON SHOWERS AND ISOLATED
THUNDERSTORMS MAY PRODUCE LOCALLY HEAVY RAINFALL, MAINLY ACROSS
INTERIOR AND SOUTHWESTERN PUERTO RICO, BUT WIDESPREAD FLOODING
IS NOT EXPECTED.
* BRIEF TROPICAL WAVE: A WEAK TROPICAL WAVE WILL MOVE QUICKLY
ACROSS THE REGION LATE FRIDAY NIGHT INTO SATURDAY MORNING,
TEMPORARILY INCREASING SHOWERS AND THUNDERSTORMS BEFORE
SIGNIFICANTLY DRIER CONDITIONS RETURN SUNDAY.
* INCREASING RIP CURRENT RISK: THE POTENTIAL FOR LIFE- THREATENING
RIP CURRENTS WILL INCREASE TO MODERATE FROM THIS EVENING ONWARD,
ESPECIALLY ALONG MOST EXPOSED BEACHES OF PUERTO RICO AND THE US
VIRGIN ISLANDS.
SHORT TERM(TODAY THROUGH FRIDAY)
ISSUED AT 303 AM AST WED AUG 26 2026
HAZY SKIES PREVAILED OVERNIGHT AS MODERATE CONCENTRATIONS OF
SAHARAN DUST REMAINED ACROSS THE REGION. LIMITED RADIATIONAL
COOLING CONTRIBUTED TO ANOTHER WARMER-THAN-NORMAL NIGHT, WITH
TEMPERATURES GENERALLY IN THE UPPER 70S TO LOW 80S ACROSS COASTAL
AREAS, LOCALLY REACHING THE MID-80S, AND CONSIDERABLY COOLER
TEMPERATURES ACROSS HIGHER ELEVATIONS AND SHELTERED VALLEYS.
DOPPLER RADAR DETECTED ONLY A FEW SHOWERS, MAINLY OVER THE LOCAL
WATERS, WHILE LIGHT TO CALM WINDS PREVAILED UNDER LAND-BREEZE
INFLUENCES.
TEMPERATURES WILL START WARMER THAN NORMAL TODAY AND, COMBINED
WITH AVAILABLE LOW-LEVEL MOISTURE, WILL RESULT IN DANGEROUSLY HIGH
HEAT INDICES. AN EXTREME HEAT WARNING IS IN EFFECT FOR URBAN AND
COASTAL PORTIONS OF PUERTO RICO, WHILE A HEAT ADVISORY IS IN
EFFECT FOR CULEBRA, VIEQUES, ST. THOMAS, ST. JOHN, AND ST. CROIX
FROM 9 AM TO 5 PM AST. MODERATE SAHARAN DUST CONCENTRATIONS WILL
ALSO KEEP SKIES HAZY AND AIR QUALITY POTENTIALLY REDUCED THROUGH
THIS EVENING.
DESPITE THE RELATIVELY DRIER AIR MASS, AVAILABLE LOW-LEVEL
MOISTURE COMBINED WITH STRONG DAYTIME HEATING, SEA-BREEZE
CONVERGENCE, AND LOCAL EFFECTS WILL SUPPORT ISOLATED TO SCATTERED
AFTERNOON SHOWERS AND THUNDERSTORMS, MAINLY ACROSS THE INTERIOR
AND SOUTHWESTERN QUADRANT OF PUERTO RICO. LOCALLY HEAVY RAINFALL
COULD RESULT IN A LIMITED FLOODING RISK. ANOTHER MOISTURE SURGE
WILL ARRIVE LATE TONIGHT INTO THURSDAY, GRADUALLY REDUCING SAHARAN
DUST CONCENTRATIONS AND INCREASING PASSING SHOWERS ACROSS THE
LOCAL WATERS AND WINDWARD PORTIONS OF PUERTO RICO AND THE USVI.
ELEVATED TO LOCALLY SIGNIFICANT HEAT RISKS WILL PERSIST THURSDAY,
PARTICULARLY ACROSS URBAN AND COASTAL AREAS. AFTERNOON CONVECTION
WILL AGAIN FAVOR INTERIOR AND WESTERN PUERTO RICO. WIDESPREAD
FLOODING IS NOT ANTICIPATED, BUT A LIMITED FLOODING RISK WILL
PERSIST WHERE LOCALLY HEAVY RAINFALL DEVELOPS.
MODEL GUIDANCE SUGGESTS INCREASING SUBSIDENCE ON FRIDAY AHEAD OF
ANOTHER WEAK TROPICAL WAVE, LIMITING SHOWER ACTIVITY THROUGH AT
LEAST FRIDAY EVENING WHILE ALLOWING THE HOT SPELL TO PERSIST
ACROSS THE ISLANDS. THE WAVE AND ITS ASSOCIATED MOISTURE ARE THEN
EXPECTED TO APPROACH LATE FRIDAY NIGHT INTO EARLY SATURDAY,
MARKING THE TRANSITION TOWARD A BRIEF WETTER PATTERN DISCUSSED IN
THE LONG TERM.
LONG TERM(SATURDAY THROUGH WEDNESDAY)
ISSUED AT 303 AM AST WED AUG 26 2026
A BRIEF, WEAK TROPICAL WAVE WILL MOVE QUICKLY ACROSS THE REGION
BETWEEN LATE FRIDAY NIGHT AND SATURDAY MORNING, TEMPORARILY
INCREASING MOISTURE AND SUPPORTING PASSING SHOWERS AND ISOLATED
THUNDERSTORMS ACROSS PUERTO RICO AND THE U.S. VIRGIN ISLANDS. A
RAPID DRYING TREND IS EXPECTED BEHIND THE WAVE, AS A DOMINANT
SURFACE HIGH SETTLES OVER THE CENTRAL ATLANTIC AND A MID-LEVEL
RIDGE BUILDS ACROSS THE REGION. DRIER AND MORE STABLE CONDITIONS
SHOULD BECOME ESTABLISHED BY SUNDAY, WITH PRECIPITABLE WATER
VALUES FALLING BELOW CLIMATOLOGICAL NORMALS TO AROUND 1.25 INCHES
THROUGH MONDAY MORNING.
UNCERTAINTY INCREASES DURING THE SECOND HALF OF THE FORECAST
PERIOD, AS LOCAL CONDITIONS WILL DEPEND ON THE TRACK AND FUTURE
INTENSITY OF TROPICAL WAVE AL96, CURRENTLY SOUTH-SOUTHWEST OF THE
CABO VERDE ISLANDS. LATEST GUIDANCE STILL SUGGESTS THE SYSTEM WILL
PASS NORTHEAST OF THE REGION BETWEEN MONDAY AFTERNOON AND
WEDNESDAY. NEVERTHELESS, ITS EVOLUTION WILL CONTINUE TO BE
MONITORED FOR POTENTIAL INDIRECT IMPACTS. GIVEN THE UNCERTAINTY,
RESIDENTS AND LOCAL INTERESTS SHOULD MONITOR SUBSEQUENT FORECASTS
AS AL96 MOVES ACROSS THE ATLANTIC.
MEANWHILE, SEASONAL TO ABOVE-SEASONAL 925-MB TEMPERATURES WILL
PERSIST THROUGHOUT THE PERIOD, RESULTING IN ELEVATED TO POSSIBLY
SIGNIFICANT HEAT RISKS EACH DAY.
AVIATION
(06Z TAFS)
ISSUED AT 303 AM AST WED AUG 26 2026
MAINLY VFR CONDS EXPECTED ACROSS ALL TERMINALS. SAHARAN DUST WILL
MAINTAIN HZ TODAY, WITH VIS GENERALLY REMAINING VFR. SHRA/ISOL
TSRA MAY DEVELOP ACROSS INTERIOR AND SW PR THIS AFTERNOON,
POTENTIALLY AFFECTING THE VCTY OF TJPS WITH BRIEF MVFR AND
MOUNT OBSC. INCREASING MOISTURE TONIGHT INTO THU WILL FAVOR
ADDITIONAL SHRA ACROSS WINDWARD PR/USVI. E-ENE WINDS AT 10-15 KT
WITH SEA BREEZE VARIATIONS AFT 26/13Z, BECOMING LIGHTER OVERNIGHT
WITH LAND BREEZE AND HIGHER GUSTS NEAR CONVECTION.
MARINE
ISSUED AT 303 AM AST WED AUG 26 2026
SURFACE HIGH ACROSS THE WESTERN AND CENTRAL ATLANTIC WILL CONTINUE
TO SUPPORT MODERATE, LOCALLY FRESH AT TIMES, EAST TO EAST-
NORTHEASTERLY STEERING FLOW TODAY BEFORE BECOMING MORE EAST TO
EAST-SOUTHEAST TOMORROW THROUGH THE REST OF THE WEEK. PATCHES OF
MOISTURE WILL CONTINUE TO STEER SHOWERS OVER THE REGION WHILE
AFTERNOON CONVECTION CAN MOVE OFF THE COAST OF WESTERN PR EACH
DAY. SAHARAN DUST CONCENTRATIONS WILL PEAK TODAY, RESULTING IN
HAZY SKIES AND SLIGHTLY REDUCED VISIBILITY, AND GRADUALLY DECREASE
LATE TONIGHT. A WEAK LONG-PERIOD NORTHERLY SWELL REMAINS FORECAST
TO ARRIVE AND SPREAD ACROSS THE REGIONAL WATERS BY TOMORROW,
THURSDAY. A BROAD MOISTURE FIELD FROM A TROPICAL WAVE IS FORECAST
TO STAY MAINLY OVER THE SOUTHERN WATERS FRIDAY TO SATURDAY.
BEACH FORECAST
ISSUED AT 303 AM AST WED AUG 26 2026
A LOW RISK OF RIP CURRENTS WILL CONTINUE UNTIL AT LEAST THIS EVENING
ACROSS THE LOCAL ISLANDS. HOWEVER, LIFE-THREATENING RIP CURRENTS
OFTEN OCCUR IN THE VICINITY OF GROINS, JETTIES, REEFS, AND PIERS.
A GRADUAL INCREASE IN WINDS AND SEAS WILL THEN RESULT IN A MODERATE
RISK OF RIP CURRENTS (LIFE-THREATENING RIP CURRENTS ARE POSSIBLE
IN THE SURF ZONE) THIS EVENING ONWARDS, PARTICULARLY ALONG THE
NORTHERN AND EASTERN-EXPOSED BEACHES OF THE ISLANDS THROUGH THE
END OF THE WEEK.
A BROAD MOISTURE FIELD FROM A TROPICAL WAVE IS FORECAST TO STAY
MAINLY SOUTH OF THE ISLANDS FRIDAY AND SATURDAY BUT CAN RESULT IN
SHOWERS AND ISOLATED T-STORMS ACROSS COASTAL AREAS. AFTERNOON
CONVECTION EACH DAY CAN ALSO AFFECT MAINLY WESTERN COASTAL AREAS
(W- SW TODAY AND W-NW TOMORROW THROUGH THE END OF THE WEEK).
BEACHGOERS SHOULD REMAIN WEATHER ALERT, AS THUNDERSTORMS COULD
PRODUCE GUSTY WINDS AND DANGEROUS LIGHTNING.
FIRE WEATHER
ISSUED AT 303 AM AST WED AUG 26 2026
A MARGINAL FIRE WEATHER RISK IS EXPECTED TODAY, PRIMARILY DUE TO
DRY FUELS. RELATIVE HUMIDITY VALUES MAY BRIEFLY DECREASE DURING
PEAK HEATING; HOWEVER, AVAILABLE LOW-LEVEL MOISTURE SHOULD KEEP
CONDITIONS ABOVE CRITICAL THRESHOLDS. WINDS WILL REMAIN BELOW
NORMAL, LIMITING THE POTENTIAL FOR RAPID FIRE SPREAD. OVERALL, DRY
FUELS REMAIN THE PRIMARY CONCERN, WHILE LIGHTER WINDS AND
SUFFICIENT HUMIDITY SHOULD LIMIT THE FIRE WEATHER THREAT.
SJU WATCHES/WARNINGS/ADVISORIES
PR...EXTREME HEAT WARNING FROM 9 AM THIS MORNING TO 5 PM AST THIS
AFTERNOON FOR PRZ001>005-007-008-010-011.
HEAT ADVISORY FROM 9 AM THIS MORNING TO 5 PM AST THIS AFTERNOON
FOR PRZ012-013.
VI...HEAT ADVISORY FROM 9 AM THIS MORNING TO 5 PM AST THIS AFTERNOON
FOR VIZ001-002.
AM...NONE.
KEY MESSAGE/SHORT TERM/AVIATION/FIRE WEATHER...CAM
LONG TERM....GRS
BEACH FORECAST/MARINE...MRR
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