483
FXCA62 TJSJ 312009
AFDSJU
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN JUAN PR
409 PM AST TUE DEC 31 2024
SYNOPSIS
MOSTLY FAIR WEATHER PREVAILED ACROSS THE REGION, EXCEPT FOR A FEW
PASSING SHOWERS OVER EASTERN PUERTO RICO. PLEASANT TEMPERATURES
WILL PERSIST FOR THE NEXT COUPLE OF DAYS. SOME SHOWERS ARE
EXPECTED FOR NEW YEAR'S DAY, ESPECIALLY EARLY IN THE MORNING
ACROSS EASTERN PUERTO RICO AND THE VIRGIN ISLANDS. CONDITIONS
COULD TURN WETTER FOR THE UPCOMING WEEKEND. LIFE THREATENING RIP
CURRENTS ARE LIKELY THROUGH THE WORKWEEK.
SHORT TERM...TONIGHT THROUGH THURSDAY
MOSTLY FAIR WEATHER CONDITIONS WILL PREVAIL ACROSS PUERTO RICO
AND THE U.S. VIRGIN ISLANDS THIS EVENING, WITH PARTLY TO MOSTLY
SKIES AND SOME BRIEF PASSING SHOWERS. NO RAINFALL ACTIVITY WAS
OBSERVED IN THE EARLY AFTERNOON HOURS, EXCEPT FOR SOME AREAS
BETWEEN VIEQUES AND CULEBRA, WHERE DOPPLER RADAR SHOWED A FEW
BRIEF SHOWERS. DAYTIME TEMPERATURES FLUCTUATED FROM THE UPPER 70S
TO THE LOWER 80S, AND COOLER IN THE MOUNTAINS.
FOR NEW YEAR'S EVE, BETWEEN 6 AND 12 PM, CLOUDINESS IS EXPECTED,
PARTICULARLY OVER THE NORTHEASTERN SECTIONS OF PUERTO RICO AND THE
U.S. VIRGIN ISLANDS. AS THE NEW YEAR STARTS, A SURGE OF MOISTURE
WILL ARRIVE ACROSS THE ISLANDS, RESULTING IN ISOLATED TO SCATTERED
SHOWERS FOR THE NORTHERN PR, FOLLOWED BY AFTERNOON SHOWERS ACROSS
SOUTHWESTERN SECTIONS. ALTHOUGH CHANCES OF RAIN ARE HIGH, WIDESPREAD
SHOWER ACTIVITY IS NOT EXPECTED. RAINFALL ACCUMULATIONS WOULD NOT
POSE A FLOOD THREAT TO THE ISLANDS. TONIGHT, TEMPERATURES WILL DROP,
BRINGING A NOTICEABLY COOLER NIGHT COMPARED TO RECENT DAYS, WITH
LOWS RANGING FROM THE UPPER 60S IN HIGHER ELEVATIONS TO THE MID-70S
IN COASTAL AREAS. HIGH TEMPERATURES ON NEW YEAR'S DAY WILL RANGE
FROM THE MID-70S IN THE MOUNTAINS TO THE MID-80S ALONG THE COASTS.
FOR THURSDAY, THE MID-LEVEL RIDGE WILL CONTINUE TO RESULT IN STABLE
WEATHER AND A STRONG CAP, INHIBITING WIDESPREAD SHOWER ACTIVITY.
HOWEVER, MOISTURE AT THE SURFACE WOULD INDUCE SOME SHOWERS ACROSS
EASTERN SECTIONS AND NORTHERN PR. FOR THE REST OF THE ISLANDS,
LIMITED MOISTURE WILL RESULT IN MOSTLY SUNNY SKIES AND ISOLATED,
BRIEF SHOWERS.
LONG TERM
FRIDAY THROUGH TUESDAY
A SURFACE HIGH PRESSURE BUILDING ACROSS THE CENTRAL ATLANTIC
NORTH OF THE ISLANDS WILL HOLD THE COLD FRONT TO THE NORTHWEST OF
THE ISLANDS ON FRIDAY. HOWEVER, AS THE COLD FRONT DRIFTS SLOWLY
EASTWARD NEAR THE NORTHEAST CARIBBEAN, AN INDUCED PRE-FRONTAL
TROUGH COULD DEVELOP OVER PR/USVI AROUND SATURDAY AFTERNOON INTO
SUNDAY. THE TRADE WINDS WILL ALSO CONTINUE TO ADVECT A COOLER AIR
MASS, THUS EXTENDING THE PERIOD OF PLEASANT TROPICAL WINTER
TEMPERATURES. MEANWHILE, POCKETS OF MOISTURE EMBEDDED IN THE
TRADES WILL OCCASIONALLY BRING QUICK PASSING SHOWERS. ALONG WITH
THE FRONT, A MID-TO UPPER-LEVEL TROUGH WILL PASS NEAR THE ISLANDS,
INCREASING LOCAL INSTABILITY OVER THE WEEKEND AND NEXT WEEK.
GIVEN THIS WEATHER PATTERN, WE CAN ANTICIPATE AN INCREASE IN
SHOWER ACTIVITY, ALONG WITH A SLIGHT TO MODERATE CHANCE OF
ISOLATED TO SCATTERED THUNDERSTORMS.
GFS HAS THE FRONTAL BOUNDARY LINGERING NORTH OR NEAR THE ISLANDS
AS IT INTERACTS WITH ONE HIGH PRESSURE OVER THE CENTRAL ATLANTIC
AND ANOTHER SURFACE HIGH BEHIND THE FRONT. MEANWHILE, THE ECMWF
MODEL SUGGESTS FROPA AROUND LATE SUNDAY NIGHT OR EARLY MONDAY
MORNING. THESE TWO SCENARIOS COULD RESULT IN SHOWERY OR DRIER,
WINDY, AND COOLER WEATHER EARLY NEXT WEEK, GFS AND ECMWF,
RESPECTIVELY. THEREFORE, WE WILL EXAMINE THIS POSSIBILITY MORE
CLOSELY AS THE DAYS APPROACHES.
AVIATION
VFR CONDITIONS WILL PREVAIL FOR ALL TAF SITES. WINDS
WILL CONTINUE FROM THE E-NE AT 12 KNOTS OR LESS WITH GUSTY WINDS
UNTIL 01/03Z. VCSH TO -SHRA ARE FORECAST FOR TJSJ, TIST & TJBQ
BETWEEN 01/03-01-15Z SHOWERS MOVE OVER THOSE AREAS. NEW YEAR
CELEBRATION NEAR TJSJ COULD LOWER VIS AND FU BETWEEN 01/03Z-01/05Z.
MARINE
MODERATE NORTHEAST WINDS IN PLACE FOR EARLY THIS WEEK UNDER A SURFACE
HIGH PRESSURE IN THE WESTERN ATLANTIC AND SURFACE LOW OVER THE
CENTRAL ATLANTIC. ANOTHER FRONT FROM THE EASTERN US COAST WILL MOVE
INTO THE WESTERN ATLANTIC BY MIDWEEK, APPROACHING THE NORTHEAST
CARIBBEAN BY THE WEEKEND. ANOTHER LONG- PERIOD NORTHERLY SWELL WILL
PROMOTE HAZARDOUS SEAS BY THE END OF THIS WEEK THROUGH THE
WEEKEND.
BEACH FORECAST
CONDITIONS WILL GRADUALLY IMPROVE ACROSS THE REGION, BUT AT LEAST
THROUGH TONIGHT, THERE WILL BE A HIGH RIP CURRENT RISK AND HIGH
SURF CONDITIONS FOR THE NORTH FACING BEACHES OF PUERTO RICO. THE
RISK WILL BE MODERATE FOR NEW YEAR'S DAY, BUT IT WILL BE HIGH
AGAIN LATE THURSDAY OR FRIDAY.
CLIMATE
THE YEAR 2024 WILL END AS THE WARMEST YEAR ON RECORD FOR THE SAN
JUAN AREA CLIMATE SITE. THESE RECORDS DATE BACK TO 1898.
ADDITIONALLY, DECEMBER 2024 WILL END AS THE SECOND WARMEST DECEMBER
ON RECORD AS WELL, FOR THE SAN JUAN AREA SITE, AND ALSO FOR HENRY E.
ROHLSEN IN SAINT CROIX.
FOR THE SAN JUAN AREA SITE, IT WILL END ALSO AS THE EIGHT WETTEST ON
RECORD, WITH 78.93 INCHES COLLECTED.
SJU WATCHES/WARNINGS/ADVISORIES
PR...HIGH RIP CURRENT RISK THROUGH LATE TONIGHT FOR PRZ001-002-005-
008-012.
HIGH SURF ADVISORY UNTIL 6 AM AST WEDNESDAY FOR PRZ001-002-005-
008-012.
HIGH RIP CURRENT RISK UNTIL 6 PM AST THIS EVENING FOR PRZ010.
VI...HIGH RIP CURRENT RISK UNTIL 6 PM AST THIS EVENING FOR VIZ001-002.
AM...NONE.
SHORT TERM...ERG
LONG TERM....GRS
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