751
FXCA62 TJSJ 231747
AFDSJU
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN JUAN PR
147 PM AST TUE JUN 23 2026
..NEW SHORT TERM, LONG TERM, AVIATION, MARINE, BEACH FORECAST
KEY MESSAGES
ISSUED AT 142 PM AST TUE JUN 23 2026
* A SMALL AREA OF CLOUDINESS AND SHOWERS WILL MOVE DURING THE REST
OF THE AFTERNOON HOURS, RESULTING IN SOME SHOWERS ALONG EASTERN
SECTIONS OF PUERTO RICO WITH MINIMAL RAINFALL ACCUMULATIONS.
* THERE IS A LOW TO MODERATE RISK OF RIP CURRENT ACROSS ALL THE
COASTAL AREAS TONIGHT.
* ANOTHER PULSE WITH MODERATE CONCENTRATIONS OF SAHARAN DUST IS
FORECAST TO ARRIVE AT THE LOCAL ISLANDS BY LATE WEDNESDAY INTO
THURSDAY.
* THE MOISTURE FIELD FROM A WEAK TROPICAL WAVE MOVING ACROSS THE
REGION BY WEDNESDAY WILL ENHANCE THE POTENTIAL FOR SOME LOCALIZED
SHOWERS TOMORROW ACROSS WESTERN INTERIOR PUERTO RICO.
SHORT TERM(THIS EVENING THROUGH THURSDAY)
ISSUED AT 142 PM AST TUE JUN 23 2026
VERY CALM WEATHER CONDITIONS PREVAILED DURING THE MORNING HOURS
ACROSS PUERTO RICO AND THE U.S. VIRGIN ISLANDS UNDER MOSTLY CLEAR
AND SUNNY SKIES. BY EARLY AFTERNOON, A BAND OF CLOUDS AND SHOWERS
AHEAD OF AN APPROACHING TROPICAL WAVE BEGAN TO MOVE ACROSS THE U.S.
VIRGIN ISLANDS, LEAVING MINOR ACCUMULATIONS OVER ST. THOMAS, ST.
JOHN, AND PORTIONS OF ST. CROIX. HOWEVER, THE REST OF THE AREA
REMAINED RELATIVELY CALM. IT WAS ANOTHER DAY WITH MAXIMUM
TEMPERATURES REACHING THE UPPER 80S TO LOW 90S ACROSS THE LOWER
ELEVATIONS, AND THE LOW TO MID-80S IN THE HIGHER MOUNTAINS. BY NOON,
THE TEMPERATURE AT THE LUIS MUNOZ MARIN INTERNATIONAL AIRPORT IN
SAN JUAN HIT 89°F. WINDS BLEW FROM THE EAST AT 15 TO 20 MPH, WITH
HIGHER GUSTS AND LOCAL SEA BREEZE VARIATIONS.
THE BAND OF SHOWERS AND CLOUDS WILL CONTINUE TO MOVE WESTWARD TOWARD
EASTERN PUERTO RICO, VIEQUES, AND CULEBRA, POTENTIALLY BRINGING
ROUNDS OF SHOWERS TO THESE AREAS THIS AFTERNOON. LATER IN THE DAY,
THIS MOISTURE WILL COMBINE WITH DAYTIME HEATING AND LOCAL EFFECTS TO
TRIGGER LOCALIZED SHOWERS AND A FEW ISOLATED THUNDERSTORMS OVER
WESTERN PUERTO RICO. THE LATEST MODEL GUIDANCE SUGGESTS MINIMAL
ACCUMULATIONS ACROSS THESE SECTORS. BY WEDNESDAY, THE TROPICAL WAVE
WILL CONTINUE TO APPROACH THE REGION; HOWEVER, THE BULK OF THE
MOISTURE IS EXPECTED TO REMAIN SOUTH OF THE AREA OVER THE CARIBBEAN
SEA, THE ABC ISLANDS, AND VENEZUELA. NONETHELESS, ITS NORTHERN
PERIPHERY WILL REACH THE NORTHEASTERN CARIBBEAN, PUSHING
PRECIPITABLE WATER VALUES (PWAT) UP TO 1.75 INCHES. GIVEN THIS
MOISTURE, SIMILAR WEATHER CONDITIONS ARE ANTICIPATED: PASSING
SHOWERS WILL MOVE ACROSS EASTERN PUERTO RICO AND THE U.S. VIRGIN
ISLANDS, FOLLOWED BY AFTERNOON CONVECTION ACROSS WESTERN PUERTO
RICO. AT THIS TIME, THE EXPECTED SHOWER ACTIVITY WILL REMAIN
LOCALIZED WITH LIMITED IMPACTS ACROSS THE AREA, THOUGH PONDING OF
WATER AND MINOR FLOODING REMAIN POSSIBLE.
BY WEDNESDAY EVENING AND INTO THURSDAY, A DRIER AIRMASS WILL FOLLOW
THE TROPICAL WAVE, BRINGING MODERATE TO HIGH CONCENTRATIONS OF
SAHARAN DUST. THIS PATTERN WILL RESULT IN HAZY SKIES, REDUCED
VISIBILITY, AND POOR AIR QUALITY. SENSITIVE GROUPS, PARTICULARLY
INDIVIDUALS WITH RESPIRATORY CONDITIONS, SHOULD TAKE THE NECESSARY
PRECAUTIONS TO LIMIT OUTDOOR EXPOSURE AND FOLLOW MEDICAL GUIDANCE.
THIS DUST EVENT IS EXPECTED TO CONTINUE THROUGH THE REST OF THE
WEEK. MEANWHILE, ABOVE-AVERAGE SEASONAL TEMPERATURES WILL PERSIST
THROUGH THE WEEKEND, WITH MAXIMUM TEMPERATURES RANGING FROM THE
UPPER 80S TO LOW 90S ALONG COASTAL AND URBAN AREAS, AND FROM THE
UPPER 70S TO LOW 80S IN THE HIGHER ELEVATIONS.
LONG TERM(FRIDAY THROUGH NEXT MONDAY)
ISSUED AT 346 AM AST TUE JUN 23 2026
VARIABLE CONDITIONS WILL PREVAIL IN THE LONG-TERM FORECAST, WITH THE
HIGHEST FLOOD POTENTIAL ON SATURDAY. THE BROAD SURFACE HIGH PRESSURE
OVER THE CENTRAL ATLANTIC MAY WEAKEN AS AN UPPER-LEVEL LOW NORTHEAST
OF THE CWA INDUCES A SURFACE TROUGH, REDUCING THE LOCAL PRESSURE
GRADIENT AND CAUSING WINDS TO BECOME LIGHT FROM THE NORTHEAST
THROUGH SATURDAY. DUE TO LINGERING MODERATE TO HIGH CONCENTRATIONS
OF SAL OVER THE REGION AND PWAT VALUES BELOW CLIMATOLOGICAL NORMAL
(1.4 AND 1.6 INCHES), WEATHER ACTIVITY SHOULD REMAIN LIMITED ON
FRIDAY, WITH SHALLOW AFTERNOON CONVECTION OVER THE
WESTERN/SOUTHWESTERN PORTION OF PUERTO RICO. FROM THE LATEST MODEL
GUIDANCE, PWAT VALUES MAY INCREASE TO SEASONAL VALUES (1.6 AND 1.8
INCHES), AS THE INDUCED TROUGH APPROACHES THE LOCAL AREA. TAKING A
LOOK AT THE LATEST MODEL CROSS-SECTION, THERE’S A RISE IN THE 850-
700 MB RH, THOUGH THE 700 - 500 MB LAYER REMAINS DRY. ADDITIONALLY,
THE LATEST MODEL SOLUTION SHOWS WARMER-THAN-NORMAL TEMPERATURES (500
MB TEMPERATURES ABOVE -6 DEGREES CELSIUS), WHILE THE GALVEZ-DAVISON
INDEX (GDI) SUGGESTS THE POTENTIAL OF ISOLATED THUNDERSTORMS.
ALTHOUGH THESE CONDITIONS AREN’T OPTIMAL FOR DEEP CONVECTION AND THE
TROUGH SHOULD REMAIN NORTH OF THE CWA, THE COMBINATION OF LOCAL
EFFECTS, DAYTIME HEATING, AVAILABLE MOISTURE, AND WEAK WINDS COULD
BRING AFTERNOON SHOWERS AND ISOLATED THUNDERSTORMS OVER THE WESTERN
SIDE OF PUERTO RICO. RAINFALL ACCUMULATIONS MAY LEAD TO PONDING OF
WATER OVER ROADWAYS, URBAN, AND POORLY DRAINED AREAS, INCLUDING
MINOR FLOODING. AS THE INDUCED TROUGH MIGRATES NORTHWESTWARD AND
WINDS STRENGTHEN FROM THE SOUTHEAST, A DRIER AIR MASS SHOULD FILTER
INTO THE REGION ON SUNDAY, LIMITING ONCE AGAIN SHOWER ACTIVITY.
HOWEVER, A TROPICAL WAVE MAY APPROACH THE CARIBBEAN BASIN AND
INCREASE LOW-LEVEL MOISTURE CONTENT ACROSS THE LOCAL ISLANDS, THOUGH
THERE’S UNCERTAINTY INTRODUCED TO THE FORECAST AS LOW TO MODERATE
CONCENTRATIONS OF SAHARAN DUST MAY WEAKEN IT AND LIMIT SHOWER
ACTIVITY.
UNDER A SOUTHEASTERLY, SUNDAY MAY BE THE HOTTEST DAY OF THE PERIOD,
WITH WARMER-THAN-NORMAL 925 MB TEMPERATURES AND AVAILABLE MOISTURE
THAT COULD MAKE HEAT INDICES EXCEED 100 DEGREES FAHRENHEIT AND POSE
A THREAT. HENCE, A HEAT ADVISORY MAY BE ISSUED IF REQUIRED.
AVIATION
(18Z TAFS)
ISSUED AT 142 PM AST TUE JUN 23 2026
VFR CONDITIONS ARE FORECAST ACROSS ALL TAF SITES. WINDS WILL REMAIN
FORM THE E-ENE AT 18 KNOTS OR LESS, DIMINISHING AT 23/23Z AND
BECOMING MORE VARIABLES UP TO 10 KNOTS AND INCREASING AGAIN BY
24/15Z. VCSH TO SHRA ARE EXPECTED ACROSS TIST AND TJSJ UNTIL 23/23Z.
HZ IS FORECAST AGAIN BY LATE WEDNESDAY AFTERNOON ACROSS TIST AND
TISX.
MARINE
ISSUED AT 142 PM AST TUE JUN 23 2026
NO CHANGES TO THE INHERITED FORECAST. AT THE SURFACE, A BROAD
SURFACE HIGH-PRESSURE SYSTEM OVER THE CENTRAL ATLANTIC WILL MAINTAIN
MODERATE TO FRESH EASTERLY TO EAST-NORTHEAST WINDS DURING THE DAY,
RESULTING IN CHOPPY SEAS ACROSS MOST OF THE LOCAL WATERS. THEREFORE,
SMALL CRAFT SHOULD EXERCISE CAUTION. A TROPICAL WAVE ARRIVING AT THE
LOCAL ISLANDS BY WEDNESDAY IS FORECAST TO PRODUCE BRIEF, STRONG
SHOWERS OVER THE LOCAL CARIBBEAN WATERS, LEADING TO LOCALIZED
HAZARDOUS MARINE CONDITIONS. ANOTHER PULSE OF MODERATE
CONCENTRATIONS OF SAHARAN DUST WILL RETURN LATE TONIGHT, WHILE HIGH
CONCENTRATIONS ARRIVE BY LATE WEDNESDAY NIGHT INTO EARLY THURSDAY
AND PERSIST THROUGH FRIDAY.
BEACH FORECAST
ISSUED AT 142 PM AST TUE JUN 23 2026
FOR TONIGHT, THERE IS A LOW TO MODERATE RISK OF RIP CURRENTS ALONG
ALL THE COASTAL AREAS. A FEW PATCHES OF CLOUDINESS AND SHOWERS ARE
FORECAST ALONG EASTERN SECTIONS OF PUERTO RICO IN THE EARLY EVENING
HOURS, RESULTING IN SOME BRIEF SHOWERS, BUT NOT SIGNIFICANT RAINFALL
ACCUMULATIONS. THE RISK OF RIP CURRENTS WILL REMAIN MODERATE FOR THE
REST OF THE WORKWEEK INTO THE UPCOMING WEEK ALONG ALL COASTAL AREAS.
HOWEVER, BEACHGOERS ARE URGED TO EXERCISE CAUTION IN SOME DANGEROUS
AREAS ALONG THE NORTH-COASTAL AREAS OF PUERTO RICO.
SJU WATCHES/WARNINGS/ADVISORIES
PR...NONE.
VI...NONE.
AM...NONE.
DAY...LIS/GRS
EVE...YZR/ICP
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