022
FXCA62 TJSJ 291701
AFDSJU
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN JUAN PR
101 PM AST FRI MAY 29 2026
..NEW SHORT TERM, LONG TERM, AVIATION, MARINE, BEACH FORECAST
KEY MESSAGES
UPDATED AT 1258 PM AST FRI MAY 29 2026
* MORE STABLE CONDITIONS ARE EXPECTED AS WE HEAD INTO THE WEEKEND
AS A SAHARAN AIR LAYER (SAL) CONTINUES TO FILTER IN, AFTERNOON
CONVECTION POSSIBLE EACH DAY.
* SAHARAN DUST CONCENTRATIONS WILL CONTINUE TO GRADUALLY INCREASE
DURING THE NEXT FEW DAYS, PARTICULARLY LATE SUNDAY THROUGH
TUESDAY.
* HAZY SKIES AND REDUCED VISIBILITY ARE FORECAST DUE TO THIS
SAHARAN DUST. SENSITIVE GROUPS, INCLUDING PEOPLE WITH
RESPIRATORY CONDITIONS, MAY EXPERIENCE DISCOMFORT AND SHOULD
FOLLOW MEDICAL RECOMMENDATIONS.
* WARMER THAN NORMAL CONDITIONS ARE EXPECTED THROUGH AT LEAST
EARLY NEXT WEEK DUE TO ESE WINDS. THIS PATTERN WILL ELEVATE THE
HEAT RISK ACROSS URBAN, COASTAL, AND LOWER-ELEVATION AREAS.
SHORT TERM(THIS EVENING THROUGH SUNDAY)
ISSUED AT 1258 PM AST FRI MAY 29 2026
CURRENT SATELLITE-DERIVED PRECIPITABLE WATER (PWAT) VALUES
INDICATE 1.45 TO 1.7 INCHES (BELOW NORMAL TO NORMAL VALUES) OVER
THE ISLANDS. THIS MOISTURE IS MOSTLY LIMITED TO BELOW 800 MB AS A
MID TO UPPER LEVEL RIDGE CONTINUES TO ESTABLISH ITSELF DURING THE
NEXT FEW DAYS. AN UPPER LEVEL TROUGH WILL ALSO LINGER EAST OF THE
LESSER ANTILLES DURING THE PERIOD. AT SURFACE LEVEL, A BROAD HIGH
OVER THE ATLANTIC WILL RESULT IN UP TO BREEZY E TO ESE WINDS
DURING THE PERIOD, AS IT TIGHTENS THE LOCAL PRESSURE GRADIENT.
PWAT VALUES ARE FORECAST TO REMAIN AT BELOW NORMAL TO NORMAL
VALUES DURING THE PERIOD AS THE STEERING FLOW CONTINUES TO STEER
PATCHES OF BOTH DRIER AND MORE HUMID AIR TOWARDS THE ISLANDS.
MAINLY PASSING SHOWERS ARE FORECAST FOR WINDWARD SECTORS WHILE
AFTERNOON CONVECTION DEVELOPS EACH DAY, PARTICULARLY OVER INTERIOR
TO W-NW PR. LOCALIZED AND ISOLATED T-STORMS ARE POSSIBLE EACH DAY
OVER W-NW PR AS COOL 500 MB TEMPERATURES (-8 TO -9 DEGREES C)
REMAIN OVER THE REGION. A NOTABLE UPTICK IN PWAT (STILL AT NORMAL
VALUES) IS FORECAST FOR SUNDAY AS MOISTURE ASSOCIATED WITH A
TROPICAL WAVE REACHES THE ISLANDS.
THROUGH THE REST OF THE SHORT TERM PERIOD AND INTO THE LONG TERM
PERIOD (NEXT WORKWEEK), SAHARAN DUST CONCENTRATIONS ARE
ANTICIPATED TO RISE, REACHING MODERATE TO LOCALLY HIGH
CONCENTRATIONS TODAY INTO EARLY SUNDAY. FROM LATE SUNDAY AND INTO
THE LONG TERM PERIOD MORE WIDESPREAD HIGH CONCENTRATIONS ARE
EXPECTED ACROSS THE REGION AS THE PEAK OF THE EVENT ARRIVES. THIS
WILL RESULT IN HAZY SKIES AND REDUCED AIR QUALITY. INDIVIDUALS IN
SENSITIVE GROUPS (SUCH AS THOSE WITH RESPIRATORY CONDITIONS, YOUNG
CHILDREN, AND OLDER ADULTS) SHOULD TAKE APPROPRIATE PRECAUTIONS
AND LIMIT PROLONGED OUTDOOR EXPOSURE DURING THIS PERIOD. WARM TO
HOT TEMPERATURES WILL PERSIST THROUGH THE WEEKEND, ESPECIALLY
ACROSS COASTAL AND URBAN AREAS. AN ELEVATED HEAT RISK IS FORECAST
FOR THESE AREAS EACH LATE MORNING TO AFTERNOON, PARTICULARLY ON
SUNDAY. THIS LEVEL OF HEAT AFFECTS MOST INDIVIDUALS SENSITIVE TO
HEAT, ESPECIALLY THOSE WITHOUT EFFECTIVE COOLING AND/OR ADEQUATE
HYDRATION.
LONG TERM(MONDAY THROUGH NEXT THURSDAY)
ISSUED AT 110 AM AST FRI MAY 29 2026
THE INHERITED FORECAST REMAINS LARGELY UNCHANGED. BY MONDAY AND
TUESDAY, FORECAST MODELS CONTINUE TO INDICATE A NOTABLE DRYING TREND
ACROSS THE NORTHEASTERN CARIBBEAN AS A BROADER AND DENSER SAHARAN
AIR LAYER (SAL) SPREADS ACROSS THE REGION, BRINGING MODERATE TO HIGH
DUST CONCENTRATIONS. PRECIPITABLE WATER (PWAT) VALUES ARE FORECAST
TO FALL BELOW NORMAL VALUES FOR THIS TIME OF THE YEAR, DROPPING TO
AROUND OR BELOW 1.25 INCHES, WHICH IS NEAR THE 25TH PERCENTILE FOR
THIS TIME OF YEAR. THIS PATTERN WILL PROMOTE DRIER AND MORE STABLE
ATMOSPHERIC CONDITIONS, LIMITING THE DEVELOPMENT OF WIDESPREAD
SHOWERS AND THUNDERSTORMS ACROSS PUERTO RICO. ANY SHOWER ACTIVITY
THAT DOES DEVELOP IS EXPECTED TO REMAIN BRIEF AND PRIMARILY CONFINED
TO WESTERN PUERTO RICO DUE TO LOCAL AND DIURNAL EFFECTS.
MIDWEEK THROUGH FRIDAY, PATCHES OF MOISTURE ARE EXPECTED TO
GRADUALLY RETURN ACROSS THE REGION, ALLOWING PWAT VALUES TO RECOVER
CLOSER TO SEASONAL LEVELS. THIS MAY SLIGHTLY INCREASE THE POTENTIAL
FOR AFTERNOON SHOWERS ACROSS PORTIONS OF NORTHWESTERN PUERTO RICO.
HOWEVER, GLOBAL MODEL GUIDANCE CONTINUES TO INDICATE LIMITED UPPER-
LEVEL SUPPORT, WHICH SHOULD HELP RESTRICT MORE ORGANIZED OR
WIDESPREAD CONVECTION. RESIDENTS AND VISITORS SHOULD CONTINUE TO
MONITOR THE FORECAST FOR THE LATEST UPDATES.
ANOTHER SIGNIFICANT CONCERN DURING THE LONG-TERM PERIOD WILL BE THE
PERSISTENCE OF WARM TO HOT DAYTIME TEMPERATURES. GUIDANCE AT THE 925
MB LEVEL CONTINUES TO INDICATE TEMPERATURES NEAR OR ABOVE THE 75TH
PERCENTILE. LIMITED CLOUD COVER, HAZY SKIES, AND PERSISTENT
SOUTHERLY WINDS WILL CONTINUE TO SUPPORT A WARMING TREND ACROSS THE
REGION, PARTICULARLY ON MONDAY. AS A RESULT, MODERATE TO ELEVATED
HEAT RISK CONDITIONS ARE EXPECTED TO PERSIST, AND HEAT ADVISORIES
MAY BECOME NECESSARY. RESIDENTS AND VISITORS ARE ENCOURAGED TO TAKE
PRECAUTIONS AGAINST HEAT-RELATED ILLNESSES BY STAYING HYDRATED,
SEEKING SHADE, AND LIMITING PROLONGED EXPOSURE TO THE SUN. IN
ADDITION, INDIVIDUALS WITH RESPIRATORY ILLNESSES OR HEIGHTENED
SENSITIVITY TO POOR AIR QUALITY SHOULD FOLLOW RECOMMENDATIONS FROM
LOCAL HEALTH AUTHORITIES DUE TO THE EXPECTED HIGH CONCENTRATIONS OF
SAHARAN DUST.
AVIATION
(18Z TAFS)
ISSUED AT 1258 PM AST FRI MAY 29 2026
MAINLY VFR CONDITIONS ACROSS THE TERMINALS. AFTERNOON SHRA/TSRA
CAN DEVELOP OVER WESTERN PR THROUGH AROUND 29/21Z, THIS CAN RESULT
IN VCTS/-TSRA. ELSEWHERE, LIMITED VCSH EXPECTED AT TIMES. HZ DUE
TO SAHARAN DUST WILL CONTINUE DURING THE PERIOD, WITH REDUCED VIS
(6 TO 8 SM) POSSIBLE. E-ESE WINDS AT 12 TO 16 KT, WITH HIGHER
GUSTS AND SEA BREEZE VARIATIONS, DECREASING AFTER 29/23Z WITH LAND
BREEZES.
MARINE
ISSUED AT 1258 PM AST FRI MAY 29 2026
A SURFACE HIGH OVER THE CENTRAL ATLANTIC WILL PROMOTE GENERALLY
MODERATE TO LOCALLY FRESH EAST TO EAST-SOUTHEAST WINDS THIS WEEKEND
INTO EARLY NEXT WEEK ACROSS THE REGION. BASED ON THE LATEST
ALTIMETER SCANS, SEAS REMAIN BETWEEN 3 AND 5 FEET, LOCALIZED TO 6
FEET, ACROSS LOCAL ATLANTIC WATERS. MARINERS MUST EXERCISE CAUTION
AS CHOPPY SEAS COULD RESULT IN LOCALIZED HAZARDOUS CONDITIONS FOR
SMALL CRAFT. BESIDES THE MARINE CONDITIONS, MARINERS SHOULD REMAIN
WEATHER ALERT AS AFTERNOON SHOWERS AND THUNDERSTORMS COULD MOVE OVER
THE COASTAL WATERS OF NORTHWESTERN PUERTO RICO TODAY. ADDITIONALLY,
MOISTURE CONTENT ASSOCIATED WITH A TROPICAL WAVE APPROACHING THE
CARIBBEAN BASIN WILL LIKELY ENHANCE SHOWER AND THUNDERSTORM ACTIVITY
ACROSS THE REGIONAL WATERS ON SUNDAY. HAZARDS MAY INCLUDE GUSTY
WINDS, REDUCED VISIBILITY, AND LIGHTNING. MODERATE CONCENTRATIONS OF
SAHARAN DUST WILL PERSIST THIS WEEKEND, BECOMING HIGHER BY LATE
SUNDAY INTO MONDAY, RESULTING IN HAZY SKIES, REDUCED VISIBILITY, AND
POOR AIR QUALITY.
BEACH FORECAST
ISSUED AT 1258 PM AST FRI MAY 29 2026
THE MODERATE RISK OF RIP CURRENTS SHOULD CONTINUE TONIGHT,
PARTICULARLY ACROSS THE NORTHERN AND EASTERN BEACHES OF PUERTO RICO,
INCLUDING CULEBRA, AND ST. CROIX IN THE U.S. VIRGIN ISLANDS, WITH A
LOW RISK ELSEWHERE. BEACHGOERS MUST EXERCISE CAUTION, AS LIFE-
THREATENING RIP CURRENTS REMAIN POSSIBLE ALONG THE BEACHES UNDER
MODERATE RISK. THIS WEEKEND, THE RISK SHOULD BE LOWER ACROSS THE
ISLANDS. HOWEVER, LIFE-THREATENING RIP CURRENTS OFTEN OCCUR NEAR
GROINS, JETTIES, REEFS, AND PIERS. THE RISK SHOULD INCREASE, ONCE
AGAIN, TO A MODERATE RISK BY MONDAY AND PERSIST FOR THE REST OF THE
FORECAST PERIOD. IN ADDITION TO RIP CURRENTS, BEACHGOERS SHOULD STAY
WEATHER ALERT AS SHOWERS AND ISOLATED THUNDERSTORMS COULD DEVELOP IN
THE AFTERNOON AND MOVE NEAR COASTAL AREAS OF NORTHWESTERN PUERTO
RICO, BRINGING GUSTY WINDS AND LIGHTNING. MODERATE CONCENTRATIONS OF
SAHARAN DUST WILL PERSIST THIS WEEKEND, WITH A DENSE LAYER REACHING
THE ISLANDS BY LATE SUNDAY INTO MONDAY, RESULTING IN HAZY SKIES,
REDUCED VISIBILITY, AND POOR AIR QUALITY.
SJU WATCHES/WARNINGS/ADVISORIES
PR...NONE.
VI...NONE.
AM...NONE.
SHORT TERM/AVIATION/KEY MESSAGES...MRR
LONG TERM....MMC
MARINE/BEACH FORECAST....MNG
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