447  
FXCA62 TJSJ 100810  
AFDSJU  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE SAN JUAN PR  
410 AM AST THU JUL 10 2025  
   
KEY MESSAGES
 
 
* SHOWERS WILL CONTINUE TO MOVE ACROSS THE ATLANTIC AND CARIBBEAN  
WATERS, AS WELL AS SOUTHERN PR THROUGH THE MORNING HOURS. LIKE  
PREVIOUS DAYS, DIURNALLY INDUCED AFTERNOON SHOWERS AND ISOLATED  
THUNDERSTORMS ARE EXPECTED OVER PORTIONS OF THE CORDILLERA  
CENTRAL AND WESTERN PR TODAY.  
 
* MODERATE TO HIGH CONCENTRATIONS OF SAHARAN DUST ARE EXPECTED TO  
RETURN LATE TONIGHT THROUGH AT LEAST SUNDAY, RESULTING IN HAZY  
SKIES, REDUCED VISIBILITY, AND POOR AIR QUALITY.  
 
* BREEZY TO LOCALLY WINDY CONDITIONS WILL PROMOTE CHOPPY SEAS AND  
A MODERATE RISK OF RIP CURRENTS OVER THE NEXT FEW DAYS.  
 

 
   
SHORT TERM...TODAY THROUGH SATURDAY
 
 
MOISTURE FROM A PASSING TROPICAL WAVE GENERATED SCATTERED SHOWERS  
AND A FEW ISOLATED THUNDERSTORMS ACROSS THE REGION OVERNIGHT. DRIVEN  
BY A STRONG STEERING LOW, SOME SHOWERS MOVED OVER EASTERN, SOUTHERN,  
AND NORTHERN PUERTO RICO AS WELL AS ST. CROIX IN THE U.S. VIRGIN  
ISLANDS, WITH A FEW REACHING FURTHER INLAND ONTO THE CENTRAL  
INTERIOR SINCE 8 PM AST. RADAR-ESTIMATED RAINFALL ACCUMULATIONS  
GENERALLY REMAINED BELOW A QUARTER OF AN INCH ACROSS MOST AREAS,  
EXPECT IN PARTS OF SOUTHERN PUERTO RICO, PARTICULARLY THE COASTAL  
AREAS OF GUAYAMA, WHERE TOTALS EXCEEDED ONE INCH. SURFACE OBSERVING  
STATIONS REPORTED A PERSISTENT GENTLE TO MODERATE BREEZE ALONG THE  
COAST AND IN SOME ELEVATED WINDWARD AREAS, WITH SUSTAINED WINDS  
AROUND 10-15 MPH AND GUSTS UP TO 25 MPH. LOW TEMPERATURES REMAINED  
WARM, IN THE LOW 80S ACROSS MOST OF NORTHEASTERN AND SOUTHERN PUERTO  
RICO, INCLUDING THE SAN JUAN METRO AREA, CULEBRA, AND THE U.,S.  
VIRGIN ISLANDS.  
 
A TROPICAL WAVE WILL CONTINUE MOVING AWAY FROM THE AREA TODAY,  
STEERED BY A BROAD SURFACE HIGH OVER THE WESTERN ATLANTIC. IN ITS  
WAKE, STRONGER EAST-SOUTHEASTERLY WINDS WILL BRING BREEZY TO WINDY  
CONDITIONS AND USER IN MUCH DRIER AIR (WITH PRECIPITABLE WATER  
DROPPING TO AROUND 1.30 INCHES, WELL BELOW TYPICAL LEVELS), ALONG  
WITH MODERATE TO HIGH CONCENTRATIONS OF SAHARAN DUST. THIS MARKS THE  
START OF A HAZIER, WARMER, AND MORE STABLE WEATHER PATTERN ACROSS  
PUERTO RICO AND THE U.S. VIRGIN ISLANDS, EXPECTED TO PERSIST  
THROUGH THE WEEKEND. MEANWHILE, A MID- TO UPPER-LEVEL TROUGH TO THE  
NORTHEAST WILL GRADUALLY DESPLACE A MID-LEVEL RIDGE AND SETTLE  
NORTHWEST OF THE AREA BY SATURDAY. HOWEVER, ITS INFLUENCE WILL  
LIKELY REMAIN LIMITED DUE TO THE DRY AND STABLE ENVIRONMENT.  
 
TODAY WILL BE A TRANSITION DAY. MORNING SHOWERS ASSOCIATED WITH THE  
DEPARTING TROPICAL WAVE MAY LINGER, FOLLOWED BY ISOLATED TO  
SCATTERED AFTERNOON SHOWERS AND ISOLATED THUNDERSTORMS OVER WESTERN  
PUERTO RICO DRIVEN BY LINGERING MOISTURE, DIURNAL HEATING AND LOCAL  
EFFECTS. INCREASING DUST AND DRY AIR WILL SUPPRESS MOST CONVECTION  
LATER IN THE DAY, REDUCING VISIBILITY AND AFFECTING AIR QUALITY,  
CONDITIONS THAT MAY IMPACT SENSITIVE GROUPS, WHILE DRIER AND FAIR  
WEATHER SPREADS ACROSS THE U.S. VIRGIN ISLANDS AND EASTERN PUERTO  
RICO. HIGHS WILL REACH THE UPPER 80S TO LOW 90S, WITH HEAT INDICES  
ELEVATED TO LEVELS WARRANTING A HEAT ADVISORY, MAINLY FOR LOWER  
ELEVATIONS AND URBAN AREAS OF PUERTO RICO  
 
FROM TONIGHT THROUGH SATURDAY, EXPECT PERSISTENTLY HAZY, DRY, AND  
WARM CONDITIONS WITH MINIMAL CHANCES FOR RAINFALL. WINDS WILL BE  
STRONGEST FRIDAY, REACHING 25-30 KNOTS BEFORE GRADUALLY EASING TO 10-  
15 KNOTS BY SATURDAY. FRIDAY IS LIKELY TO BE THE HAZIEST AND HOTTEST  
DAY, WITH ABUNDANT SUNSHINE AND LIMITED RELIEF FROM THE BREEZE.  
HOWEVER, WARM CONDITIONS WILL POTENTIALLY PROMPT THE ISSUANCE OF  
HEAT ADVISORIES EVERY DAY. RESIDENTS AND VISITORS ARE ADVISED TO  
TAKE APPROPRIATE PRECAUTIONS DURING THIS PERIOD, ESPECIALLY THOSE  
SENSITIVE TO REDUCED AIR QUALITY AND HEAT.  
   
LONG TERM...SUNDAY THROUGH THURSDAY
 
 
ON SUNDAY, SAHARAN DUST CONCENTRATIONS WILL BEGIN TO DIMINISH.  
HOWEVER, WE STILL ANTICIPATE HAZY SKIES ACROSS THE U.S. VIRGIN  
ISLANDS AND PUERTO RICO. THE LATEST MODEL GUIDANCE CONTINUES TO  
INDICATE A TROPICAL UPPER-TROPOSPHERIC TROUGH (TUTT) SHIFTING  
WESTWARD TOWARDS HISPANOLA AND LINGERING THERE THROUGH THE  
BEGINNING OF THE WORKWEEK WEAKENING THE HIGH PRESSURE SYSTEM AT  
THE SURFACE AND FORCING THE BREEZY TO LOCALLY WINDY CONDITIONS TO  
DIMINISH. ON MONDAY AND TUESDAY, THE APPROACH OF EASTERLY TRADE  
WIND PERTURBATIONS WILL GRADUALLY ENHANCE MOISTURE LEVELS ACROSS  
THE REGION. AS ATMOSPHERIC MOISTURE INCREASES, SO WILL THE  
POTENTIAL FOR SHOWER AND THUNDERSTORM ACTIVITY, PARTICULARLY  
DURING THE AFTERNOON HOURS OVER WESTERN AND SOUTHWESTERN PUERTO  
RICO, WITH POCKETS OF SHOWERS OVER EASTERN PUERTO RICO IN THE  
MORNING HOURS. ADDITIONALLY, MODEL GUIDANCE INDICATE THAT MOISTURE  
WILL EXTEND FROM THE SURFACE THROUGH THE MID AND UPPER LEVELS OF  
THE ATMOSPHERE, SUPPORTING INCREASED ATMOSPHERIC INSTABILITY AND  
ENHANCING THE POTENTIAL FOR CONVECTIVE DEVELOPMENT DURING THIS  
PERIOD. BY MIDWEEK, A TROPICAL WAVE IS EXPECTED TO APPROACH THE  
FORECAST AREA, BRINGING INCREASED TROPICAL MOISTURE. HOWEVER, THE  
MOST INTENSE PART OF THE WAVE IS EXPECTED TO PASS SOUTH OF PUERTO  
RICO AND THE U.S. VIRGIN ISLANDS. NEVERTHELESS, SCATTERED SHOWERS  
AND THUNDERSTORMS ARE ANTICIPATED EACH AFTERNOON, ESPECIALLY  
ACROSS INTERIOR AND WESTERN AREAS. WE WILL CONTINUE TO MONITOR  
CONDITIONS CLOSELY FOR ANY SIGNIFICANT CHANGES.  
 

 
   
AVIATION
 
 
(06Z TAF)  
 
SHRA/TSRA WILL LIKELY AFFECT TJSJ, TJPS, AND USVI TERMINALS  
THROUGH 10/13Z, WITH AFTERNOON SHRA/TSRA EXPECTED NEAR TJBQ  
BETWEEN 10/17-23Z, POSSIBLY CAUSING BRIEF MVFR CONDITIONS. VCSH  
ARE ALSO POSSIBLE AROUND TJSJ AND USVI TERMINALS THROUGHOUT THE  
PERIOD, ESPECIALLY AFTER 10/23Z. MODERATE TO HIGH CONCENTRATIONS  
OF SAHARAN DUST WILL GENERATE HAZY SKIES, WITH VISIBILITIES  
REDUCED TO 5-6 SM AFTER 10/13Z. BREEZY TO LOCALLY WINDY WINDS OF  
16-22 KNOTS BETWEEN 10/13- 23Z, DIMINISHING TO 10-15 KNOTS AFTER  
10/23Z.  
 

 
   
MARINE
 
 
AN EASTERLY PERTURBATION WILL CONTINUE TO REACH THE LESSER ANTILLES  
AND MOVE NEAR THE US VIRGIN ISLANDS AND PUERTO RICO BY LATE TODAY  
AND EARLY FRIDAY MORNING. ANOTHER PULSE OF SUSPENDED SAHARAN DUST  
PARTICLES WILL ARRIVE AS EARLY AS LATE TONIGHT AND PERSIST THROUGH  
THE WEEKEND.  
 

 
   
BEACH FORECAST
 
 
BREEZY TO LOCALLY WINDY CONDITIONS OVER THE NEXT SEVERAL DAYS  
WILL PROMOTE A PERSISTENT MODERATE RISK OF RIP CURRENTS ACROSS  
MOST LOCAL BEACHES OF PUERTO RICO AND THE US VIRGIN ISLANDS.  
BEACHGOERS ARE ENCOURAGED TO EXERCISE CAUTION AS LIFE-THREATENING  
RIP CURRENTS ARE POSSIBLE IN THE SURF ZONE.  
 

 
   
SJU WATCHES/WARNINGS/ADVISORIES
 
 
PR...HEAT ADVISORY FROM 10 AM THIS MORNING TO 5 PM AST FRIDAY FOR  
PRZ001>005-007-008-010-011.  
 
VI...NONE.  
AM...SMALL CRAFT ADVISORY UNTIL NOON AST TODAY FOR AMZ711.  
 

 
 

 
 
SHORT TERM/AVIATION...ICP  
LONG TERM/MARINE/BEACH FORECAST...MMC  
 
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