533  
FXCA62 TJSJ 060900  
AFDSJU  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE SAN JUAN PR  
500 AM AST SUN JUL 6 2025  
   
KEY MESSAGES  
 
* HIGH-LEVEL CLOUDS MAY SLIGHTLY REDUCE DAYTIME HEATING, BUT A  
LIMITED RISK OF EXCESSIVE HEAT REMAINS, ESPECIALLY AFFECTING  
SENSITIVE GROUPS.  
 
* FIRE DANGER IS ELEVATED TODAY ACROSS SOUTHERN PUERTO RICO DUE TO  
VERY DRY SOILS AND FUELS, LOW HUMIDITY, AND BREEZY CONDITIONS,  
INCREASING POTENTIAL FOR RAPID FIRE SPREAD AFTER IGNITION.  
 
* PERSISTENT SAHARAN DUST WILL MAINTAIN HAZY SKIES AND REDUCED  
VISIBILITY TODAY, WHICH MAY IMPACT OUTDOOR ACTIVITIES.  
 
* RIP CURRENT RISK IS LOW TODAY BUT WILL RISE TO MODERATE TONIGHT  
AND IN THE COMING DAYS. EXERCISE CAUTION, ESPECIALLY ON EXPOSED  
BEACHES.  
 
 
   
SHORT TERM...TODAY THROUGH TUESDAY  
 
 
MOSTLY STABLE WEATHER CONDITIONS PREVAILED DURING THE NIGHT HOURS  
ACROSS ALL THE LOCAL ISLANDS. LATE IN THE NIGHT AND INTO THE EARLY  
MORNING HOURS, A FEW ISOLATED THUNDERSTORMS WERE DETECTED BY DOPPLER  
RADAR OVER THE MONA PASSAGE. THESE THUNDERSTORMS REMAINED OVER THE  
WATERS AND DID NOT AFFECT LAND AREAS. AROUND 2 AM, SOME ISOLATED  
SHOWERS WERE OBSERVED ACROSS THE EASTERN SIDE. SHOWER ACTIVITY WAS  
RELATIVELY INSIGNIFICANT, AND RAINFALL ACCUMULATIONS WERE MINIMAL.  
OVERNIGHT TEMPERATURES RANGED IN THE 80S ACROSS THE COASTAL AREAS  
AND THE U.S. VIRGIN ISLANDS, AND IN THE LOWER 70S ACROSS MOST OF THE  
MOUNTAIN AREAS, WITH SOME LOCATIONS REPORTING TEMPERATURES IN THE  
UPPER 60S. WINDS REMAINED FROM THE EAST AT UP TO 10 MPH, WITH LAND  
BREEZE VARIATIONS.  
 
THE FORECAST REMAINS ON TRACK. TODAY, THE ISLANDS WILL BE UNDER A  
BREEZY PATTERN WITH EASTERLY WINDS AS A BROAD SURFACE HIGH-PRESSURE  
SYSTEM REMAINS IN PLACE ACROSS THE CENTRAL ATLANTIC, TIGHTENING THE  
PRESSURE GRADIENT. UNDER THIS PATTERN, SAHARAN DUST PARTICLES WILL  
PERSIST ACROSS THE REGION. ACCORDING TO THE NASA GODDARD EARTH  
OBSERVING SYSTEM MODEL V5, VALUES OF AEROSOL OPTICAL DEPTH THICKNESS  
[550 NM] WILL STAY BETWEEN 0.20 AND 0.30. THIS PATTERN WILL FAVOR  
MOSTLY HAZY SKIES WITH SOME CLOUDINESS THROUGHOUT THE DAY.  
WIDESPREAD SHOWER ACTIVITY IS NOT EXPECTED; HOWEVER, AFTERNOON  
CONVECTION IS POSSIBLE ACROSS THE WESTERN INTERIOR DUE TO LOCAL AND  
DIURNAL EFFECTS, WITH A LIMITED FLOODING THREAT FOR THE DAY.  
ADDITIONALLY, THERE WILL BE A LIMITED HEAT THREAT ACROSS THE COASTAL  
AND URBAN AREAS WITH HEAT INDICES THAT COULD REACH 105 TO 108  
DEGREES.  
 
FOR THE REST OF THE SHORT-TERM PERIOD, STABILITY WILL PERSIST AS A  
MID-LEVEL RIDGE REMAINS IN PLACE, PROVIDING DRIER AIR ALOFT AND A  
STRONG TRADE WIND CAP OVER THE ISLANDS. ALTHOUGH STABLE WEATHER  
CONDITIONS WILL CONTINUE, TRAPPED MOISTURE AT THE 850 MB LEVEL WILL  
FAVOR SOME DIURNAL CONVECTION, MOSTLY BETWEEN 12 PM AND 5 PM ACROSS  
THE WESTERN INTERIOR. FOR TUESDAY, DESPITE PREVIOUS DISCUSSIONS  
MENTIONING A TROPICAL WAVE MOVING NEAR THE AREA, INCREASING THE  
POTENTIAL FOR SHOWERS, GLOBAL MODELS NOW INDICATE THAT THE BULK OF  
THE MOISTURE ASSOCIATED WITH THIS DISTURBANCE WILL REMAIN WELL SOUTH  
OF THE ISLANDS. THEREFORE, WHILE SOME MOISTURE IS STILL EXPECTED,  
WIDESPREAD SHOWER ACTIVITY IS NOT FORECAST AT THIS TIME.  
   
LONG TERM...WEDNESDAY THROUGH SUNDAY  
 
A TRADE WIND PERTURBATION WILL AFFECT THE REGION WEDNESDAY,  
BRINGING BRIEF PERIODS OF ENHANCED MOISTURE AND LOCALIZED SHOWERS.  
FOLLOWING THIS, A WEAK TROPICAL WAVE WILL CROSS THE AREA THURSDAY  
INTO FRIDAY, STEERED WESTWARD BY A STRONG BERMUDA-AZORES HIGH. A  
WIND SURGE WILL THEN BRING BREEZY TO WINDY CONDITIONS FRIDAY INTO  
THE WEEKEND, WITH 700 MB WINDS PEAKING NEAR 35–40 KNOTS. THIS  
PATTERN WILL SUPPORT ENHANCED LOW-LEVEL MOISTURE TRANSPORT, THOUGH  
MID- TO UPPER-LEVEL DRYNESS AND A STRONG TRADE WIND CAP INVERSION  
WILL LIMIT DEEPER MOISTURE AVAILABILITY AND CONVECTION. DRY AIR  
ABOVE 850 MB WILL PERSIST DUE TO SUBSIDENCE FROM MID-LEVEL RIDGING  
AND LATER REINFORCED BY A TROPICAL UPPER-TROPOSPHERIC TROUGH  
(TUTT) EXPECTED TO CROSS THE REGION SATURDAY. THE MOST SIGNIFICANT  
DRYING WILL OCCUR INTO EARLY SUNDAY, WITH PRECIPITABLE WATER  
(PWAT) FALLING WELL BELOW CLIMATOLOGICAL NORMS.  
 
LIMITED PHASING OF MOISTURE AND INSTABILITY WILL RESTRICT  
WIDESPREAD OR ORGANIZED CONVECTION; HOWEVER, SOME AFTERNOON  
CONVECTION REMAINS LIKELY EACH DAY FOLLOWING THE GENERAL WIND FLOW  
AND DRIVEN BY DIURNAL HEATING AND LOCAL EFFECTS. ACTIVITY MAY  
INCREASE LATE SUNDAY AS THE TUTT SHIFTS WEST AND PWAT RETURNS TO  
TYPICAL LEVELS. A MODERATE TO HIGH SAHARAN AIR LAYER (SAL) EVENT  
IS ANTICIPATED FROM THURSDAY ONWARD, COINCIDING WITH THE DRYING  
TREND AND STRENGTHENING WINDS. THIS WILL CONTRIBUTE TO HAZY SKIES,  
REDUCED VISIBILITY, AND OVERALL ATMOSPHERIC STABILITY.  
 
WINDS WILL GENERALLY FLOW FROM EAST TO EAST-SOUTHEAST, SHIFTING  
BRIEFLY TO EAST-NORTHEAST SATURDAY NIGHT INTO SUNDAY AS THE  
SURFACE HIGH REPOSITIONS OVER THE WESTERN ATLANTIC. TEMPERATURES  
WILL REMAIN NEAR SEASONAL NORMS, WITH FRIDAY LIKELY THE WARMEST  
DAY DUE TO THE STRONGEST SOUTHEASTERLY FLOW COMPONENT. EXCEPT FOR  
EXCESSIVE RAINFALL HAZARDS, ALL OTHER WEATHER HAZARDS—INCLUDING  
PERIODS OF EXCESSIVE HEAT, GUSTY WINDS, AND ISOLATED AFTERNOON  
LIGHTNING—ARE POSSIBLE THROUGH THE LONG-TERM PERIOD.  
 
 
   
AVIATION  
 
(06Z TAF)  
 
VFR CONDITIONS WILL PERSIST ALONG ALL THE TAF SITES DURING THE  
PERIOD. HZ AND A DIMINUTION OF VIS ARE STILL FORECAST UNTIL 07/23Z.  
VCSH TO SHRA IS POSSIBLE ACROSS TJBQ AT AROUND 07/19Z IF A SHOWER  
DEVELOPS ALONG THE WESTERN INTERIOR, DIMINISHING THE VISIBILITY  
AND LOWERING THE CEILINGS. WINDS WILL PEAK AT 07/15Z FROM THE E UP  
TO 15 KNOTS WITH GUSTY WINDS.  
 
 
   
MARINE  
 
MODERATE EASTERLY WINDS WILL PREVAIL TODAY, BUT LOCAL EFFECTS WILL  
LEAD TO CHOPPY SEAS NEAR COASTAL AREAS, PROMPTING SMALL CRAFT  
OPERATORS TO EXERCISE CAUTION. MODERATE TO LOCALLY FRESH WINDS  
WILL RETURN TONIGHT AND PERSIST OVER THE NEXT FEW DAYS, EXPANDING  
THE AREA WHERE CAUTION IS ADVISED. SAHARAN DUST WILL KEEP SKIES  
HAZY THROUGH TONIGHT, WITH ANOTHER EVENT EXPECTED LATER IN THE  
WORKWEEK. AFTERNOON THUNDERSTORMS MAY AFFECT COASTAL WATERS AND  
LOCAL PASSAGES, PARTICULARLY NEAR WESTERN PUERTO RICO, EACH DAY.  
IN ADDITION, TROPICAL WAVES APPROACHING TUESDAY AND THURSDAY WILL  
LIKELY INCREASE THE CHANCES FOR SHOWERS, THUNDERSTORMS, GUSTY  
WINDS, AND LOCALLY HIGHER SEAS.  
 
 
   
BEACH FORECAST  
 
MODERATE WINDS AND IMPROVED MARINE CONDITIONS WILL RESULT IN A LOW  
RIP CURRENT RISK ACROSS ALL BEACHES TODAY. HOWEVER, AS WINDS  
INCREASE TONIGHT AND PERSIST THROUGH THE UPCOMING DAYS, THE RIP  
CURRENT RISK IS EXPECTED TO GRADUALLY RISE TO MODERATE IN SELECT  
AREAS—BEGINNING ALONG NORTHWESTERN PUERTO RICO TONIGHT, THEN  
EXTENDING TO THE NORTH-CENTRAL COAST, CULEBRA, AND SAINT CROIX ON  
MONDAY, AND REACHING VIEQUES AND SOUTHEASTERN PUERTO RICO BY  
MONDAY NIGHT. BEACHGOERS ARE ADVISED TO EXERCISE CAUTION,  
PARTICULARLY AT EXPOSED NORTHERN AND EASTERN SHORELINES. FOR THE  
LATEST AND MOST DETAILED UPDATES ON RIP CURRENT RISKS, PLEASE  
CONSULT THE SURF ZONE FORECAST (SRFSJU).  
 
 
   
FIRE WEATHER  
 
THE FIRE DANGER RISK IS ELEVATED TODAY AS WINDS BACK FROM THE EAST  
AND A DRIER AIR MASS MOVES INTO THE AREA. PERSISTENT HIGH-LEVEL  
CLOUDS MAY SLIGHTLY REDUCE DAYTIME HEATING, THOUGH THEY ARE  
UNLIKELY TO SIGNIFICANTLY INCREASE HUMIDITY OR PRODUCE RAINFALL,  
THUS HAVING MINIMAL IMPACT ON LOWERING FIRE DANGER. BREEZY  
CONDITIONS COMBINED WITH LOWER RELATIVE HUMIDITIES, AND VERY DRY  
AND DETERIORATED SOILS AND FUELS—ESPECIALLY IN THE DRIEST  
SOUTHERN PLAINS AND HILLS OF PUERTO RICO—WILL SUPPORT AN INCREASED  
POTENTIAL FOR FIRE SPREAD. REFER TO THE LATEST FIRE DANGER  
STATEMENT (RFDSJU) FOR ADDITIONAL GUIDANCE.  
 
 
   
SJU WATCHES/WARNINGS/ADVISORIES  
 
PR...NONE.  
VI...NONE.  
AM...NONE.  
 
 
 
 
SHORT TERM...LIS  
LONG TERM....ICP  
AVIATION...LIS  
PUBLIC...ICP/LIS  
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