016
FXCA62 TJSJ 260857
AFDSJU
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN JUAN PR
457 AM AST THU JUN 26 2025
KEY MESSAGES
*AN AREA WITH SLIGHTLY DRIER AIR AND SUSPENDED SAHARAN DUST
PARTICLES WILL PROMOTE HAZY SKIES AT LEAST THROUGH FRIDAY.
ANOTHER ROUND IS POSSIBLE EARLY NEXT WEEK.
*A TRADE WIND PERTURBATION WILL BRING FREQUENT PASSING AND A
BETTER CHANCE FOR AFTERNOON THUNDERSTORMS ON FRIDAY.
*ANOTHER TROPICAL WAVE IS EXPECTED TO APPROACH PUERTO RICO AND
THE U.S. VIRGIN ISLANDS FROM THE EASTERN CARIBBEAN BY LATE
SATURDAY INTO SUNDAY.
*WINDS AND CHOPPY SEAS WILL CONTINUE TO PROMOTE LIFE-THREATENING
RIP CURRENTS.
SHORT TERM...TODAY THROUGH SATURDAY
WEATHER CONDITIONS OVERNIGHT REMAINED MOSTLY CALM ACROSS PUERTO RICO
AND THE U.S. VIRGIN ISLANDS, WITH HAZY SKIES AND A LIGHT TO MODERATE
EASTERLY BREEZE BETWEEN 8 TO 20 MPH, ESPECIALLY STRONGER NEAR
COASTAL AREAS. TEMPERATURES RANGED FROM THE UPPER 70S TO LOW 80S IN
URBAN AREAS AND FROM THE HIGH 60S TO LOW 70S IN MOUNTAINOUS AREAS.
THE PRESENCE OF SAHARAN DUST CONTRIBUTED TO THE HAZY CONDITIONS AND
TYPICAL SUMMER TEMPERATURES.
TODAY, A RELATIVELY STABLE WEATHER PATTERN IS EXPECTED TO PERSIST
ACROSS THE REGION AS A MID-LEVEL RIDGE CONTINUES TO DOMINATE,
MAINTAINING MOSTLY DRY CONDITIONS. SUSPENDED SAHARAN DUST WILL STILL
AFFECT AIR QUALITY AND VISIBILITY. THEREFORE, CITIZENS AND VISITORS
ARE ENCOURAGED TO FOLLOW THE RECOMMENDATIONS OF THE HEALTH
DEPARTMENT. TEMPERATURES ARE EXPECTED TO REMAIN IN THE UPPER 80S TO
LOW 90S IN URBAN AND COASTAL AREAS AND THE UPPER 70S TO LOW 80S AT
HIGHER ELEVATIONS. BREEZY CONDITIONS SHOULD PREVAIL.
AS THE SAHARAN AIR LAYER SHIFTS WESTWARD AND EXITS THE AREA BY
FRIDAY, A GRADUAL INCREASE IN LOW-LEVEL MOISTURE IS EXPECTED, WITH
PRECIPITABLE WATER VALUES RISING TO BETWEEN 1.40 AND 1.70 INCHES. BY
FRIDAY INTO SATURDAY, THE ADDITIONAL MOISTURE COMBINED WITH AN
APPROACHING UPPER-LEVEL TROUGH WILL CREATE A MORE UNSTABLE
ATMOSPHERE. THESE EVOLVING CONDITIONS WILL INCREASE THE POTENTIAL
FOR CONVECTIVE DEVELOPMENT, PARTICULARLY DURING THE AFTERNOON HOURS.
EXPECT SCATTERED TO NUMEROUS SHOWERS AND ISOLATED THUNDERSTORMS,
ESPECIALLY ACROSS THE INTERIOR AND WESTERN PORTIONS OF PUERTO RICO,
AS WELL AS DOWNWIND FROM THE U.S. VIRGIN ISLANDS.
LONG TERM...SUNDAY THROUGH THURSDAY
A SOMEWHAT UNSTABLE AND WET WEATHER PATTERN IS EXPECTED TO UNFOLD
ACROSS THE REGION BEGINNING THIS WEEKEND. A RETROGRADING MID- TO
UPPER-LEVEL TROUGH/LOW OVER THE MONA PASSAGE WILL CONTINUE TO MOVE
WESTWARD OVER THE BAHAMAS. AT THE SAME TIME, A TROPICAL WAVE
APPROACHING FROM THE EAST WILL BRING A NOTABLE SURGE IN TROPICAL
MOISTURE ACROSS THE FORECAST AREA. THIS INTERACTION WILL ENHANCE
THE POTENTIAL FOR SHOWERS AND THUNDERSTORMS, PARTICULARLY SUNDAY
AFTERNOON INTO THE EVENING HOURS, WITH THE GREATEST RISK FOR
FLOODING RAINS CONCENTRATED DURING THAT PERIOD. RESIDENTS AND
VISITORS SHOULD MONITOR FOR LOCALIZED FLOODING, ESPECIALLY IN
AREAS WITH POOR DRAINAGE OR NEAR STEEP TERRAIN.
FOLLOWING THIS UNSETTLED PERIOD, CONDITIONS ARE EXPECTED TO
STABILIZE AS A MID-LEVEL RIDGE BUILDS AND HOLDS OVER THE NORTHEAST
CARIBBEAN BY EARLY NEXT WEEK. THIS FEATURE WILL ESTABLISH A TRADE
WIND INVERSION, PROMOTING SUBSIDENCE AND A DRIER ATMOSPHERE
ALOFT, WHICH WILL SIGNIFICANTLY LIMIT DEEP CONVECTIVE DEVELOPMENT
THROUGH MIDWEEK. ADDITIONALLY, A SAHARAN AIR LAYER (SAL) IS
FORECAST TO ARRIVE BEHIND THE TROPICAL WAVE, RESULTING IN HAZY
SKIES, DEGRADED AIR QUALITY, AND REDUCED VISIBILITY FROM MONDAY
THROUGH AT LEAST TUESDAY. WHILE A TROPICAL WAVE WILL BE MOVING
SOUTHWARD WELL AWAY FROM THE AREA, THE LOCAL WEATHER WILL REMAIN
INFLUENCED BY POCKETS OF MOISTURE EMBEDDED WITHIN EASTERLY TRADE
WINDS, OCCASIONALLY PRODUCING BRIEF SHOWERS ACROSS WINDWARD
COASTAL REGIONS, ESPECIALLY DURING NIGHTTIME AND EARLY MORNING
HOURS. AFTERNOON CONVECTION WILL REMAIN LOCALIZED, MAINLY
AFFECTING WESTERN PUERTO RICO DUE TO DIURNAL, SEA BREEZE AND
TOPOGRAPHIC INFLUENCES.
TEMPERATURES ARE EXPECTED TO TREND ABOVE NORMAL, ESPECIALLY UNDER
THE INFLUENCE OF THE SAL, WHICH WILL REDUCE OVERNIGHT COOLING AND
RESULT IN WARMER MINIMUM AND MAXIMUM TEMPERATURES ACROSS THE
ISLANDS.
AVIATION
(06Z TAFS)
VFR CONDITIONS ACROSS ALL TAF SITES. EXPECT HAZY SKIES WITH
VISIBILITIES AROUND 6SM DUE TO A SAL, WHICH WILL LIMIT RAINFALL
ACTIVITY. NONETHELESS, VCTS POSSIBLE NEAR TJBQ AROUND 26/18Z-23Z.
EXPECT E WINDS RANGING FROM 10-25 KT WITH OCCASIONAL HIGHER GUSTS
THROUGH AT LEAST 26/23Z.
MARINE
THE SURFACE HIGH PRESSURE ACROSS THE ATLANTIC WILL SUPPORT MODERATE
TO FRESH EASTERLY WINDS, RESULTING IN CHOPPY SEAS OVER LOCAL ATLANTIC
AND CARIBBEAN WATERS. THE PRESENCE OF SUSPENDED SAHARAN DUST WILL
CONTINUE TO RESULT IN REDUCE VISIBILITY THROUGH LATE TONIGHT. A
TRADE WIND PERTURBATION WILL ARRIVE AROUND FRIDAY, INCREASING THE
POTENTIAL FOR SHOWERS AND THUNDERSTORMS, FOLLOWED BY ANOTHER TROPICAL
WAVE LATE SATURDAY NIGHT INTO SUNDAY.
BEACH FORECAST
WIND-DRIVEN SEAS WILL MAINTAIN A MODERATE RISK OF RIP CURRENTS
ALONG MOST EXPOSED BEACHES OF THE ISLANDS TODAY AND THROUGH MUCH
OF THE FORECAST PERIOD.
SJU WATCHES/WARNINGS/ADVISORIES
PR...NONE.
VI...NONE.
AM...NONE.
SHORT TERM...MMC
LONG TERM....CAM
AVIATION...MMC
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