984
FXCA62 TJSJ 221726
AFDSJU
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN JUAN PR
126 PM AST TUE JUL 22 2025
KEY MESSAGES
* THE BULK OF MOISTURE ASSOCIATED WITH A TROPICAL WAVE LOCATED NEAR
52W (FORMERLY AL94) IS EXPECTED TO REMAIN SOUTH OF THE AREA.
NEVERTHELESS, AN INCREASE IN SHOWER AND THUNDERSTORM ACTIVITY,
WITH AN ELEVATED RISK OF FLOODING, IS EXPECTED ON SUNDAY AND
MONDAY, ASSOCIATED WITH THE PASSAGE OF THE FOLLOWING TROPICAL
WAVE NOW LOCATED NEAR 35W.
* IN THE NEAR TERM, MAIN HAZARDS CONTINUE TO BE A MODERATE TO
HIGH RISK OF RIP CURRENTS ACROSS MOST SHORELINES AND CHOPPY TO
HAZARDOUS SEAS MAINLY IN CARIBBEAN WATERS, BOTH ASSOCIATED WITH
BREEZY TO WINDY CONDITIONS.
* HAZINESS ASSOCIATED WITH SAHARAN DUST PARTICLES WILL CONTINUE
TO PREVAIL ACROSS THE LOCAL AREA THROUGH AT LEAST MIDWEEK AS
WELL AS HEAT INDICES EXCEEDING 100 DEGREES ALONG LOWER
ELEVATIONS.
SHORT TERM...TONIGHT THROUGH THURSDAY
MOSTLY SUNNY TO PARTLY CLOUDY SKIES PREVAILED DURING THE MORNING
HOURS, BECOMING VARIABLY CLOUDY IN THE AFTERNOON. A FEW PASSING
SHOWERS WERE OBSERVED ACROSS COASTAL AREAS AND LOCAL WATERS IN THE
MORNING, WITH MINIMAL RAINFALL ACCUMULATIONS OVER LAND AREAS.
DURING THE AFTERNOON HOURS, SHOWER DEVELOPMENT IS STILL EXPECTED
ACROSS WESTERN AREAS OF PUERTO RICO. NEVERTHELESS, SHOWER ACTIVITY
IS LIKELY TO DIMINISH AROUND SUNSET, LEAVING THE SKIES PARTLY
CLOUDY.
A MID-LEVEL RIDGE PATTERN WILL CONTINUE TO STRENGTHEN ACROSS THE
FORECAST AREA THROUGH THE CYCLE. AT LOWER LEVELS, A SURFACE HIGH
PRESSURE NORTH OF THE AREA AND A TROPICAL WAVE...WHICH IS
EXPECTED TO MOVE SOUTH OF THE AREA ON THU...WILL CONTINUE TO
YIELD MODERATE TO FRESH EASTERLY WINDS THE NEXT FEW DAYS WITH
WEDNESDAY AND THURSDAY BEING THE BREEZY TO WINDY DAYS. IN TERMS OF
PRECIPITABLE WATER, THE BULK OF MOISTURE ASSOCIATED WITH THE
TROPICAL WAVE...NOW LOCATED NEAR 52W (FORMERLY AL94)...IS
EXPECTED TO REMAIN SOUTH OF THE AREA AND CONFINED BELOW 850MB.
HAVING SAID THIS, CONTINUE TO EXPECT OCCASIONAL PASSING SHOWERS
ACROSS THE EASTERN COASTAL AREAS, AS WELL AS AFTERNOON SHOWERS
DEVELOPING IN WESTERN AREAS WEDNESDAY AND THURSDAY. DUE TO THE
BREEZY TO WINDY CONDITIONS, SHOWERS ARE EXPECTED TO BE FAST-
MOVING, LEAVING MAINLY PONDING OF WATER IN POORLY DRAINED AREAS.
AT THIS TIME, THE MAIN HAZARDS CONTINUE TO BE A MODERATE TO HIGH
RISK OF RIP CURRENTS ACROSS MOST SHORELINES, CHOPPY TO HAZARDOUS
SEAS PRIMARILY IN CARIBBEAN WATERS, AND HEAT INDICES EXCEEDING 100
DEGREES ALONG LOWER ELEVATIONS.
LONG TERM...ISSUED 448 AM AST TUE JUL 22 2025 /FRI THRU TUE
VARIABLE CONDITIONS ARE STILL EXPECTED IN THE LONG-TERM FORECAST,
WITH A TRANSITION TO A WETTER AND UNSETTLED WEATHER PATTERN LIKELY
BY THE START OF NEXT WEEK. DRIER AIR WILL CONTINUE FILTERING INTO
THE REGION DUE TO A MID-TO-UPPER LEVEL RIDGE LINGERING NORTH OF THE
CWA. BASED ON THE LATEST MODEL GUIDANCE, PRECIPITABLE WATER VALUES
(PWAT) SHOULD DECREASE TO SEASONAL VALUES (1.5 - 1.7 INCHES). THE
MOST LIKELY SCENARIO IS TO EXPECT SHOWERS EMBEDDED IN THE TRADES
MOVING OVER WINDWARD SECTIONS IN THE MORNING HOURS AND AFTERNOON
CONVECTION OVER WESTERN/NORTHWESTERN PUERTO RICO. RAINFALL
ACCUMULATIONS ARE LIKELY TO PROMOTE PONDING OF WATER IN ROADWAYS AND
POORLY DRAINED AREAS, WITH ISOLATED URBAN AND SMALL STREAMS FLOODING
OVER THE AFOREMENTIONED AREAS. ANOTHER TROPICAL WAVE WITH HIGH
MOISTURE CONTENT WILL LIKELY APPROACH THE CWA BY SATURDAY NIGHT
THROUGH MONDAY. ADDITIONALLY, AN UPPER-LEVEL LOW SHOULD APPROACH THE
REGION BY FRIDAY AND LINGER THROUGH SUNDAY, INCREASING INSTABILITY
ALOFT AND BRINGING FAVORABLE CONDITIONS FOR DEEPER CONVECTION
ACTIVITY. BASED ON DETERMINISTIC GUIDANCE OF THE GFS AND ECMWF, PWAT
VALUES MAY EXCEED THE 75TH PERCENTILE (2.0 - 2.2 INCHES, WITH LOW
CHANCES OF REACHING 2.4 INCHES), WHICH IS WELL ABOVE CLIMATOLOGICAL
NORMAL. THIS WILL ENHANCE THE SHOWER AND THUNDERSTORM ACTIVITY OVER
THE LOCAL ISLANDS, ELEVATING THE FLOODING RISK FOR MOST SECTIONS OF
PUERTO RICO AND THE U.S. VIRGIN ISLANDS. CITIZENS AND VISITORS MUST
PAY ATTENTION TO THE FOLLOWING DISCUSSION REGARDING THIS TROPICAL
WAVE. DRIER AIR MAY FILTER ONCE AGAIN INTO THE REGION BY MONDAY
NIGHT, BRINGING MOSTLY FAIR CONDITIONS ACROSS THE CWA.
WITH AVAILABLE MOISTURE AND WARMER TEMPERATURES, HEAT INDEXES ARE
LIKELY TO EXCEED THE 100 DEGREES FAHRENHEIT WHICH MAY AFFECT MOST
INDIVIDUALS SENSITIVE TO HEAT. HENCE, THE HEAT RISK IS LIKELY TO
REMAIN LIMITED TO ELEVATED FOR URBAN AND COASTAL AREAS OF PUERTO
RICO AND THE U.S. VIRGIN ISLANDS FOR THE REST OF THE FORECAST
PERIOD.
AVIATION
(18Z)
VFR CONDITIONS ARE EXPECTED TO PREVAIL AT ALL TAF SITES WITH
EASTERLY WIDS BETWEEN 15 TO 20 KNOTS, BECOMING AT AROUND 12 KNOTS
OVERNIGHT. VCTS AT JBQ THROUGH 22/22Z. HAZINESS DUE TO SAHARAN
DUST PARTICLES ACROSS THE FLYING AREAS, BUT VISIBILITIES REMAINING
GREATER THAN 6 SM.
MARINE
A MODERATE TO FRESH TRADE WIND FLOW WILL CONTINUE TO PREVAIL
THROUGH THE REST OF THE WEEK. AS A RESULT, CHOPPY TO HAZARDOUS
SEAS ARE EXPECTED WITH SMALL CRAFT ADVISORIES IN EFFECT FOR
WEDESDAY. AN INCREASE IN SHOWERS AND THUNDERSTORMS, WITH AN
ELEVATED RISK OF FLOODING, IS EXPECTED ON SUNDAY AND MONDAY,
ASSOCIATED WITH THE PASSAGE OF THE FOLLOWING TROPICAL WAVE
NOW LOCATED NEAR 35W.
BEACH FORECAST
ISSUED 448 AM AST TUE JUL 22 2025
A MODERATE RISK OF RIP CURRENTS ACROSS MOST LOCAL BEACHES TODAY.
AS WINDS ARE EXPECTED TO CONTINUE TO INCREASE THROUGH WEDNESDAY,
THIS MODERATE RIP CURRENT RISK IS EXPECTED TO EXPAND TO THE
EASTERN COAST OF PUERTO RICO AND GRADUALLY AFFECT OTHER COASTAL
AREAS THROUGHOUT THE WEEK. THESE RIP CURRENTS CAN BE STRONG AND
POTENTIALLY LIFE THREATENING, ESPECIALLY AREAS NOT DESIGNATED FOR
SWIMMING. RESIDENT AND VISITORS ARE STRONGLY URGED TO EXERCISE
CAUTION WHEN VISITING THE COAST, PARTICULARLY ON UN-PATROLLED OR
REMOTE BEACHES. ALWAYS FOLLOW GUIDANCE FROM LOCAL AUTHORITIES AND
HEED POSTED WARNING SIGNS TO ENSURE YOUR SAFETY.
SJU WATCHES/WARNINGS/ADVISORIES
PR...NONE.
VI...NONE.
AM...NONE.
SHORT TERM...OMS
LONG TERM....MNG
AVIATION...OMS
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