487  
FXCA62 TJSJ 051852  
AFDSJU  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE SAN JUAN PR  
252 PM AST SAT JUL 5 2025  
   
KEY MESSAGES  
 
* SAHARAN DUST PARTICLES WILL REMAIN ACROSS THE REGION RESULTING  
IN HAZY SKIES AT LEAST UNTIL MONDAY.  
 
* HOT AND BREEZY CONDITIONS WILL CONTINUE ON SUNDAY ACROSS  
COASTAL AREAS.  
 
* A MODERATE RISK OF RIP CURRENTS WILL RETURN NEXT WEEK ACROSS  
MOST EAST, NORTHERN, AND SOUTHERN BEACHES OF THE ISLANDS.  
 
* A HEAT ADVISORY IS IN EFFECT THROUGH 4 PM AST THIS AFTERNOON  
FOR THE LOWER ELEVATIONS AND URBAN AREAS OF PUERTO RICO.  
 
 
 
   
SHORT TERM...THIS AFTERNOON THROUGH MONDAY  
 
SUNNY TO PARTLY CLOUDY AND HAZY SKIES PREVAILED ACROSS PUERTO  
RICO AND THE U.S. VIRGIN ISLANDS TODAY. DIURNALLY INDUCED  
AFTERNOON SHOWERS AND ISOLATED THUNDERSTORMS DEVELOPED OVER THE  
NORTHWEST QUADRANT OF PR, WHILE STREAMERS WERE OBSERVED DOWNWIND  
OF THE USVI. MAXIMUM TEMPERATURES WERE FROM THE MID-80S TO THE  
LOW 90S ACROSS THE LOWER ELEVATIONS OF THE ISLANDS, AND FROM THE  
UPPER-70S TO MID-80S ACROSS THE HIGHER ELEVATIONS OF PUERTO RICO.  
THE WIND WAS FROM THE EAST TO SOUTHEAST BETWEEN 15 AND 20 MPH  
WITH SEA BREEZE VARIATIONS AND HIGHER GUSTS ACROSS COASTAL AREAS.  
 
FOR THE REST OF THIS AFTERNOON, THE DIURNALLY INDUCED SHOWERS AND  
ISOLATED THUNDERSTORMS WILL CONTINUE MAINLY OVER THE WEST COAST  
AND WESTERN WATERS OF PR. GUSTY WINDS AND OCCASIONAL LIGHTNING  
STRIKES ARE EXPECTED WITH THIS ACTIVITY. ACROSS THE USVI AND  
EASTERN PR, BREEZY CONDITIONS AND SHALLOW CLOUDINESS WITH LIMITED  
SHOWER ACTIVITY IS EXPECTED. FOR THE REST OF THE WEEKEND, A DENSE  
SAHARAN AIR LAYER(SAL) WITH SUSPENDED SAHARAN DUST WILL PERSIST,  
RESULTING IN HAZY SKIES, POOR AIR QUALITY, AND REDUCED  
VISIBILITIES. A WEAK LOW-TO MID-LEVEL RIDGE OVER THE REGION WILL  
PROMOTE A TRADE WIND CAP INVERSION. THIS IN ADDITION TO THE SAL  
WILL LIMIT MOISTURE CONTENT ACROSS THE ISLANDS. IN GENERAL, SHOWER  
ACTIVITY WILL DEVELOP MAINLY DUE TO LOCAL AND DIURNAL EFFECTS OVER  
WESTERN PR. WINDS WILL ACQUIRE A MORE EASTERLY COMPONENT ON  
SUNDAY, AND ENE ON MONDAY.  
 
BY MONDAY, A WEAK TRADE WIND PERTURBATION WILL MOVE INTO THE  
REGION, BRINGING PASSING SHOWERS INTO THE AREA, AND AIDING IN THE  
DEVELOPMENT OF SHOWERS AND THUNDERSTORMS ACROSS THE INTERIOR AND  
WESTERN PR. ACROSS THE USVI, MOSTLY SCATTERED SHOWERS ARE  
EXPECTED FROM TIME TO TIME. ALTHOUGH NO WIDESPREAD SIGNIFICANT  
RAIN IS ANTICIPATED, SOME MINOR URBAN AND SMALL STREAM FLOODING IS  
POSSIBLE WITH THE THUNDERSTORMS. TEMPERATURES WILL BE JUST A TAD  
LOWER, BUT STILL WITH A LIMITED HEAT RISK ANTICIPATED FOR PUERTO  
RICO.  
   
LONG TERM...TUESDAY TROUGH SUNDAY  
 
 
ON TUESDAY, A TROPICAL WAVE IS EXPECTED TO PASS WELL SOUTH OF THE  
REGION, BUT A PATCH OF SHALLOW MOISTURE CONTENT SHOULD ARRIVE BY  
TUESDAY EVENING FROM THE EAST/NORTHEAST. INCREASING PASSING  
SHOWERS ONCE AGAIN THROUGH THE NIGHT ACROSS THE USVI AND EASTERN  
PR.  
 
/FROM PREV DISCUSSION ISSUED AT 441 AM AST SAT JUL 5 2025/  
 
A BROAD SURFACE HIGH PRESSURE ANCHORED ACROSS THE CENTRAL  
ATLANTIC WILL DOMINATE THE WEATHER PATTERN ACROSS PUERTO RICO AND  
THE U.S. VIRGIN ISLANDS FROM WEDNESDAY THROUGH SUNDAY. THIS  
FEATURE WILL PROMOTE SOUTHEASTERLY WINDS THROUGH SATURDAY,  
GRADUALLY SHIFTING TO AN EASTERLY FLOW LATE SATURDAY INTO SUNDAY  
AS THE HIGH EXTENDS WESTWARD INTO THE WESTERN ATLANTIC. AT MID TO  
UPPER LEVELS, A RIDGE PATTERN WILL ESTABLISH OVER THE REGION,  
PROMOTING INCREASINGLY STABLE CONDITIONS AND SUPPRESSING VERTICAL  
CLOUD DEVELOPMENT. AS A RESULT, SIGNIFICANT CONVECTION IS NOT  
EXPECTED DURING THE PERIOD, WITH ONLY BRIEF AND ISOLATED SHOWERS  
POSSIBLE ACROSS EASTERN AREAS DURING THE OVERNIGHT AND EARLY  
MORNING HOURS.  
 
A SURGE OF SAHARAN DUST WILL AFFECT THE ISLANDS FROM LATE  
WEDNESDAY THROUGH SUNDAY, LEADING TO HAZY SKIES AND FURTHER  
REDUCING SHOWER ACTIVITY. THE LATEST GUIDANCE FROM THE NASA  
GODDARD EARTH OBSERVING SYSTEM MODEL V5 SUGGESTS THAT THE HIGHEST  
CONCENTRATION OF SAHARAN DUST IS EXPECTED ON FRIDAY AND SUNDAY,  
WITH AEROSOL OPTICAL DEPTH VALUES RANGING BETWEEN 0.20 AND 0.30.  
THIS WILL RESULT IN THE DRIEST AND HAZIEST CONDITIONS DURING THOSE  
DAYS, MAINTAINING AN OVERALL PATTERN OF WARM, STABLE, AND MOSTLY  
DRY WEATHER THROUGH THE WEEKEND.  
 
 
   
AVIATION  
 
(18Z TAFS)  
 
MAINLY VFR CONDITIONS ARE EXPECTED TO PREVAIL ACROSS ALL TERMINALS  
DURING THE NEXT 24 HOURS. HOWEVER, SHRA/TSRA IN AND AROUND TJBQ  
MAY CAUSE TEMPO MVFR CONDS THRU 05/22Z. HZ DUE TO SAHARAN DUST  
EXPECTED TO CAUSE VSBY TO DROP TO NEAR 6SM THRU SUNDAY EVENING.  
THE 05/12Z TJSJ SOUNDING INDICATED ESE WINDS UP TO 18 KT BLO  
FL050.  
 
 
   
MARINE  
 
A BROAD SURFACE HIGH PRESSURE OVER THE CENTRAL ATLANTIC WILL  
CONTINUE TO RESULT IN MODERATE TO FRESH EASTERLY WINDS ACROSS THE  
REGION. THEREFORE, WIND-DRIVEN SEAS WILL RESULT IN CHOPPY MARINE  
CONDITIONS ACROSS THE ATLANTIC WATERS AND THE CARIBBEAN WATERS FOR  
THE FOLLOWING DAYS. SAHARAN DUST PARTICLES WILL BE IN PLACE AT  
LEAST UNTIL MONDAY, RESULTING IN HAZY SKIES AND LIMITED SHOWER  
ACTIVITY.  
 
 
   
BEACH FORECAST  
 
THERE IS A LOW RISK OF RIP CURRENTS FOR ALL ISLANDS THROUGH THE  
REST OF THE WEEKEND. HOWEVER, LIFE-THREATENING RIP CURRENTS OFTEN  
OCCUR IN THE VICINITY OF GROINS, JETTIES, REEFS, AND PIERS.  
 
FOR THE UPCOMING WORKWEEK THE RISK OF RIP CURRENT WILL BECOME  
MODERATE ACROSS THE NORTHERN COASTAL AREAS OF PUERTO RICO ON  
MONDAY, AND EXTENDING INTO THE EAST AND SOUTHEAST COASTS AND  
ACROSS ST. CROIX FROM TUESDAY ONWARD.  
 
 
   
SJU WATCHES/WARNINGS/ADVISORIES  
 
PR...HEAT ADVISORY UNTIL 4 PM AST THIS AFTERNOON FOR PRZ001>005-007-  
008-010-011.  
 
VI...NONE.  
AM...NONE.  
 
 
 
 
DSR/GRS  
CLICK HERE TO GO TO PREVIOUS BULLETINS.
The Nexlab PR Page
Main Text Page