005
FXCA62 TJSJ 010843
AFDSJU
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN JUAN PR
443 AM AST SAT MAR 1 2025
SYNOPSIS
A FEW PASSING SHOWERS ARE EXPECTED TO MOVE INTO THE ISLANDS TODAY,
WITH STRONGER SHOWERS DEVELOPING IN THE NORTHWESTERN CORNER OF
PUERTO RICO THIS AFTERNOON. SOME SAHARAN DUST WILL FILTER IN,
RESULTING IN HAZY SKIES. A TROUGH WILL APPROACH BY MIDWEEK, WITH
HEAVY SHOWERS EXPECTED TO DEVELOP ACROSS THE INTERIOR AND WESTERN
PUERTO RICO EACH AFTERNOON. BREEZY CONDITIONS WILL PROMOTE CHOPPY
SEAS THIS WEEKEND, WITH A MODERATE RIP OF RIP CURRENTS
ANTICIPATED.
SHORT TERM...TODAY THROUGH MONDAY
CURRENT SATELLITE DERIVED PRECIPITABLE WATER (PWAT) IMAGERY SHOW AN
AREA OF MOISTURE OVER THE USVI, VIEQUES, CULEBRA AND EASTERN PUERTO
RICO WITH VALUES RANGING FROM 1.45 TO 1.50 INCHES. DURING THE
OVERNIGHT HOURS LIGHT TO MODERATE SHOWERS STEERED, BY EAST-SOUTHEAST
WINDS, REACHED THE AFOREMENTIONED AREAS. LOWS WERE IN THE UPPER 60S
(PUERTO RICO) TO MID 70S ACROSS COASTAL AREAS OF THE ISLANDS AND IN
THE LOW 60S (LOCALLY COOLER) AT HIGHER ELEVATIONS OF PUERTO RICO.
THE AREA OF MOISTURE WILL MOVE OVER THE ISLANDS DURING THE DAY,
FOLLOWED BY A TRANSITION INTO DRIER PATTERN LATE IN THE AFTERNOON
INTO TOMORROW. THIS WILL BE DUE TO A MASS OF DRIER AIR THAT WILL
REACH THE ISLANDS AND DECREASE PWAT VALUES TO AROUND AN INCH.
PASSING SHOWERS WILL MOVE INTO THE EASTERN REGION DURING THE MORNING
HOURS. DURING THE AFTERNOON, CONVECTIVE SHOWER ACTIVITY WILL
CONCENTRATE OVER NORTHWESTERN PUERTO RICO, PROMOTING A LIMITED
EXCESSIVE RAINFALL RISK. BOTH POCKETS OF MORE HUMID AND POCKETS OF
DRIER AIR WILL REACH THE REGION SUNDAY AND MONDAY, PASSING ADVECTIVE
SHOWERS WILL STILL AFFECT WINDWARD SECTORS OF THE ISLANDS DURING THE
OVERNIGHT TO MORNING HOURS AND AFTERNOON CONVECTIVE SHOWERS WILL
AFFECT W-NW PR EACH DAY. THESE SHOWERS WILL CONTINUE TO BE UNDER E-
SE FLOW AS A SURFACE HIGH CENTERED OVER THE EASTERN ATLANTIC WILL
CONTINUE TO PROMOTE THESE INCREASING WINDS. IN THE MID TO UPPER
LEVELS, HIGH PRESSURE WILL BE PRESENT THROUGHOUT THE SHORT TERM
PERIOD, WITH MOST AVAILABLE MOISTURE REMAINING BELOW 700MB. LOW
CONCENTRATIONS OF SAHARAN DUST WILL FILTER INTO THE REGION DURING
THE WEEKEND, PROMOTING HAZY SKIES. THE EAST-SOUTHEASTERLY FLOW WILL
PROMOTE WARMER THAN NORMAL TEMPERATURES, PARTICULARLY DURING THE
AFTERNOONS. 925MB TEMPERATURES, WILL FLUCTUATE BETWEEN 1 TO 2
STANDARD DEVIATIONS ABOVE THE CLIMATOLOGICAL MEAN. HIGHS WILL REACH
THE LOW TO MID 80S AT LOWER ELEVATIONS OF THE ISLANDS, WITH SOME
AREAS REACHING THE UPPER 80S, AND THE UPPER 70S TO LOW 80S AT HIGHER
ELEVATIONS OF PUERTO RICO.
LONG TERM...TUESDAY THROUGH SATURDAY
A MID TO UPPER LEVEL TROUGH WILL BE APPROACHING THE ISLANDS BY
TUESDAY. A PIECE OF THE JET STREAM WILL ALSO REACH THE ISLANDS,
WHILE TEMPERATURES AT 500 MB WILL COOL DOWN TOO. AS A RESULT,
INSTABILITY ALOFT WILL BE INCREASED, ENHANCING THE POTENTIAL FOR
STRONG AFTERNOON SHOWERS DEVELOPING ACROSS THE INTERIOR OF PUERTO
RICO. THE AREAS THAT WILL RECEIVE THE STRONGEST WINDS WILL DEPEND ON
THE DOMINANT WINDS FOR EACH DAY. EASTERLY WINDS ON MONDAY WILL
TRANSPORT THE SHOWERS TOWARD THE WEST, BUT WINDS WILL BE MORE
SOUTHEASTERLY ON TUESDAY, SO THE NORTHWEST WILL LIKELY EXPERIENCE
THE STRONGEST RAINS. THE WIND FLOW COULD SLOW DOWN BY WEDNESDAY, SO
THE RAIN WILL LINGER ACROSS THE INTERIOR, THEN BEING TRANSPORTED
SOUTHWARD BY THE NORTHERLY MID-LEVEL WINDS. WHILE THE MAIN THREAT IS
EXPECTED TO BE LOCALIZED URBAN AND SMALL STREAM FLOODING, THE
INSTABILITY AND DIURNAL HEATING COULD AID IN THE DEVELOPMENT OF
LIGHTNING TOO, SO THUNDERSTORMS WERE ADDED TO THE FORECAST. BY THE
END OF THE WEEK, YET ANOTHER MID TO UPPER LEVEL TROUGH WILL APPROACH
THE REGION. THE PATTERN WILL AGAIN FAVOR THE FORMATION OF SHOWERS
ACROSS THE INTERIOR AND WESTERN PUERTO RICO EACH AFTERNOON.
EACH DAY OF THE WORKWEEK, THE WINDS WILL ALSO CARRY SOME SHOWERS
OVER EASTERN PUERTO RICO AND THE VIRGIN ISLANDS TOO. IT IS WORTH
MENTIONING THAT MOISTURE CONTENT IS NOT EXPECTED TO BE TOO ABUNDANT,
ACTING AS A LIMITING FACTOR FOR THE INTENSITY OF THE AFTERNOON RAIN.
ALSO, TRACES OF SAHARAN DUST WILL LINGER INTO TUESDAY, RESULTING IN
HAZY SKIES.
AVIATION
(06Z TAFS)
MAINLY VFR CONDITIONS EXPECTED. VCSH AND POSSIBLY -SHRA WILL AFFECT
TJSJ/TIST/TISX DURING THE MORNING HOURS, GRADUALLY DECREASING IN
COVERAGE. AFTER 01/17Z, SHOWERS WILL ALSO DEVELOP OVER NW PR AND
AFFECT TJBQ, POSSIBLY LEADING TO BRIEF PERIODS OF REDUCED VIS AND
LOW CEILINGS, ESPECIALLY FOR TJBQ. ESE AT 12-18 KTS, WITH STRONGER
GUSTS, AFTER 01/13Z.
MARINE
A BROAD SURFACE HIGH PRESSURE OVER THE EASTERN ATLANTIC WILL PROMOTE
MODERATE TO LOCALLY FRESH WINDS THIS WEEKEND. SMALL CONCENTRATIONS OF
SAHARAN DUST WILL RESULT IN HAZY SKIES, BUT VISIBILITIES SHOULD
REMAIN GREATER THAN 10 MILES. PASSING SHOWERS WILL CONTINUE ACROSS
THE CARIBBEAN AND ATLANTIC WATERS.
BEACH FORECAST
INCREASING WINDS WILL MAINTAIN A MODERATE RISK OF LIFE THREATENING
RIP CURRENTS ALONG THE NORTH, EAST, AND SOUTHEAST COAST OF PUERTO
RICO, AS WELL AS FOR VIEQUES, CULEBRA, SAINT THOMAS, SAINT JOHN,
AND SAINT CROIX.
SJU WATCHES/WARNINGS/ADVISORIES
PR...NONE.
VI...NONE.
AM...NONE.
SHORT TERM...MRR
LONG TERM....ERG
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