615  
FXCA62 TJSJ 091857  
AFDSJU  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE SAN JUAN PR  
257 PM AST WED JUL 9 2025  
   
KEY MESSAGES
 
 
* PASSING SHOWERS WILL CONTINUE ACROSS THE USVI AND EASTERN  
SECTIONS OF PR TONIGHT INTO THURSDAY MORNING HOURS. DIURNALLY  
INDUCED AFTERNOON SHOWERS AND ISOLATED THUNDERSTORMS ARE  
EXPECTED OVER PORTIONS OF THE CORDILLERA CENTRAL AND WESTERN PR  
EACH DAY.  
 
* BREEZY TO LOCALLY WINDY CONDITIONS WILL PROMOTE CHOPPY SEAS AND  
A MODERATE RISK OF RIP CURRENTS OVER THE NEXT FEW DAYS.  
 
* 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.  
 

 
   
SHORT TERM...TONIGHT THROUGH FRIDAY
 
 
A WIND SURGE WILL PROMOTE ROUGH SEAS DUE TO MODERATE TO LOCALLY  
FRESH WINDS ACROSS THE LOCAL WATERS, ACCOMPANIED BY SCATTERED TO  
NUMEROUS SHOWERS THROUGH AT LEAST THURSDAY MORNING. ANOTHER EASTERLY  
PERTURBATION WILL REACH THE LESSER ANTILLES LATE TONIGHT, MOVING  
NEAR THE US VIRGIN ISLANDS AND PUERTO RICO BY LATE THURSDAY NIGHT  
AND EARLY FRIDAY MORNING. ANOTHER PULSE OF SUSPENDED SAHARAN DUST  
PARTICLES WILL ARRIVE AS EARLY AS LATE TONIGHT AND PERSIST THROUGH  
THE WEEKEND.  
 
OVERNIGHT, SCATTERED TO NUMEROUS SHOWERS MOVED ACROSS THE LOCAL  
WATERS, WITH SOME REACHING WINDWARD AREAS OF THE U.S. VIRGIN ISLANDS  
AND PUERTO RICO. THIS ACTIVITY WAS ASSOCIATED WITH A WIND SURGE THAT  
INCREASED LOCAL WINDS AND GENERATED ROUGH SEAS FOR MARINERS. SKIES  
WERE VARIABLY CLOUDY, WITH TEMPERATURES RANGING FROM THE LOW TO MID-  
60S IN THE MOUNTAINS AND VALLEYS TO THE UPPER 70S AND LOW 80S IN  
URBAN COASTAL AREAS.  
 
A WIND SURGE WILL BRING SCATTERED SHOWERS AND STRONGER WINDS ACROSS  
THE REGION STARTING TODAY. FROM THURSDAY TO EARLY FRIDAY MORNING, A  
TROPICAL WAVE ACCOMPANIED BY A BAND OF MOISTURE WITH PRECIPITABLE  
WATER VALUES RANGING FROM 1.85 TO 2.10 INCHES WILL MOVE THROUGH THE  
AREA. HOWEVER, HIGHER CONCENTRATIONS OF SAHARAN DUST EMBEDDED WITHIN  
THE WAVE MAY LIMIT OVERALL SHOWER DEVELOPMENT. AS A RESULT, A  
SIMILAR WEATHER PATTERN IS EXPECTED EACH DAY, WITH PASSING SHOWERS  
ACROSS THE U.S. VIRGIN ISLANDS AND EASTERN PUERTO RICO DURING THE  
NIGHT AND EARLY MORNING, FOLLOWED BY AFTERNOON CONVECTION OVER  
CENTRAL AND WESTERN PUERTO RICO AND STREAMER DEVELOPMENT DOWNWIND OF  
THE USVI AND EL YUNQUE. LOCALIZED IMPACTS MAY INCLUDE PONDING OF  
WATER ON ROADS, POORLY DRAINED AREAS, AS WELL AS URBAN AND SMALL  
STREAM FLOODING, PARTICULARLY DURING HEAVIER THUNDERSTORMS. MOISTURE  
WILL RAPIDLY ERODE AFTER FRIDAY MORNING.  
 
ADDITIONALLY, BASED ON THE LATEST MODEL GUIDANCE, AN AREA OF  
SUSPENDED SAHARAN DUST PARTICLES IS FORECAST TO MOVE ACROSS PUERTO  
RICO AND THE U.S. VIRGIN ISLANDS AS EARLY AS TONIGHT, CONTINUING  
THROUGH THE WEEKEND. THIS WILL RESULT IN HAZY SKIES, REDUCED  
VISIBILITY, AND DETERIORATED AIR QUALITY ACROSS THE REGION.  
SENSITIVE GROUPS SHOULD TAKE PRECAUTIONARY MEASURES, AS AIRBORNE  
PARTICULATES MAY IMPACT RESPIRATORY HEALTH.  
 
RECENT OBSERVATIONS SUGGESTED THE ARRIVAL OF A POCKET OF DRY AIR  
ACROSS THE SOUTHERN SLOPES RESULTING IN RH DROPS AROUND THE LOW AND  
MID 50S WITH SUSTAINED WINDS BETWEEN 15 MPH AND HIGHER GUSTS.  
   
LONG TERM...SATURDAY THROUGH WEDNESDAY
 
   
PREV DISCUSSION
 
/ISSUED 452 AM AST WED JUL 9 2025/  
 
THE LATEST MODEL GUIDANCE CONTINUES TO INDICATE THE ARRIVAL OF  
SAHARAN DUST PARTICLES ALONG WITH A NOTABLY DRY AIRMASS THROUGH AT  
LEAST LATE SUNDAY. ADDITIONALLY, MID TO UPPER LEVEL DRY AIR AND A  
REINFORCING TRADE WIND INVERSION WILL FURTHER INHIBIT VERTICAL  
CLOUD DEVELOPMENT, SUPPRESSING WIDESPREAD CONVECTION. WITH THIS  
SETUP, RESIDENTS AND VISITORS IN PUERTO RICO AND THE U.S. VIRGIN  
ISLANDS CAN EXPECT HAZY SKIES, REDUCED VISIBILITY, AND POTENTIAL  
AIR QUALITY CONCERNS, PARTICULARLY FOR INDIVIDUALS WITH  
RESPIRATORY CONDITIONS. BREEZY CONDITIONS WILL PREVAIL THROUGH  
SATURDAY, WITH PERSISTENT EASTERLY WINDS SUPPORTING ABOVE-NORMAL  
TEMPERATURES, ESPECIALLY ACROSS COASTAL AND URBAN AREAS.  
 
BY SUNDAY, A TROPICAL UPPER-TROPOSPHERIC TROUGH (TUTT) IS FORECAST  
TO SHIFT WESTWARD TOWARD HISPANIOLA AND LINGER THERE THROUGH  
MIDWEEK. BEGINNING MONDAY, 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.  
 
TUESDAY CURRENTLY APPEARS TO HAVE THE HIGHEST RAINFALL POTENTIAL AS  
A TROPICAL WAVE APPROACHES THE FORECAST AREA, BRINGING DEEPER  
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
 
 
(18Z TAFS)  
 
MAINLY VFR CONDS ARE EXPECTED TO PREVAIL ACROSS ALL TERMINALS.  
HOWEVER, EXPECT DIURNALLY INDUCED AFTERNOON SHRA OVER THE INTERIOR  
AND W-PR AND DOWNWIND FROM EL YUNQUE, WITH MOST OF THE ACTIVITY IN  
THE VCTY OF OUR TERMINALS. SOME SHRA/-SHRA WILL FORM NEAR THE USVI  
AND E-PR TERMINALS, BTWN 10/02-12Z. HIGHER CONCENTRATIONS OF SAHARAN  
DUST RETURN FROM THURSDAY ONWARD AND VISIBILITIES COULD DROP TO 5-6  
SM. WINDS WILL CONTINUE E-ENE AT 15-25 KT WITH HIGHER GUSTS AND SEA  
BREEZE VARIATIONS, WINDS WILL RETURN AROUND 10 KT AFT 09/23Z.  
 

 
   
MARINE
 
 
A SURFACE HIGH PRESSURE ACROSS THE ATLANTIC WITH PROMOTE MODERATE  
TO FRESH EASTERLY WINDS RESULTING IN SMALL CRAFT ADVISORIES ACROSS  
THE OFFSHORE AND ONSHORE ATLANTIC WATERS AND THE ANEGADA PASSAGE  
THROUGH AT LEAST THURSDAY MORNING AND CHOPPY SEAS ACROSS MOST LOCAL  
WATERS OVER THE NEXT FEW DAYS. AN EASTERLY PERTURBATION WILL REACH  
THE AREA TONIGHT, INCREASING THE FREQUENCY OF SHOWERS ACROSS THE  
WATERS. ADDITIONALLY, ANOTHER PULSE OF SUSPENDED SAHARAN DUST  
PARTICLES WILL ARRIVE LATE TONIGHT AND PERSIST THROUGH NEXT SUNDAY  
RESULTING IN HAZY SKIES AND REDUCED VISIBILITY.  
 

 
   
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...NONE.  
VI...NONE.  
AM...SMALL CRAFT ADVISORY UNTIL NOON AST THURSDAY FOR AMZ711.  
 
SMALL CRAFT ADVISORY UNTIL MIDNIGHT AST TONIGHT FOR AMZ712.  
 
SMALL CRAFT ADVISORY UNTIL 6 AM AST THURSDAY FOR AMZ723.  
 

 
 

 
 
SHORT TERM/AVIATION...CAM  
LONG TERM...MMC  
PUBLIC...YZR  
 
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