771
FXCA62 TJSJ 192006
AFDSJU
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN JUAN PR
406 PM AST TUE NOV 19 2024
SYNOPSIS
STABLE AND DRIER PATTERN WILL PREVAIL FOR THE REST OF THE NIGHT
INTO TOMORROW DUE TO THE DRIER AIRMASS DOMINATING THE AREA.
WEATHER CONDITIONS WILL BECOME MORE WET ONCE AGAIN ON FRIDAY, WHEN
WINDS AT SURFACE CHANGE FROM THE SOUTHEAST AND DRAG MOISTURE
ACROSS THE REGION.
SHORT TERM...TODAY THROUGH THURSDAY
MOSTLY SUNNY TO PARTLY CLOUDY SKIES PREVAILED ACROSS THE ISLANDS
TODAY. SCATTERED SHOWERS WERE NOTED MAINLY ACROSS THE ATLANTIC
WATERS, AND THE SOUTHERN WATERS OF VIEQUES. LITTLE TO NO RAINFALL
WAS OBSERVED OVER LAND AREAS BY 3 PM AST. HIGH TEMPERATURES WERE IN
THE MID TO UPPER 80S ACROSS MOST LOWER ELEVATIONS, AND ONCE AGAIN IN
THE LOW 90S IN PONCE AND GUANICA. WIND GUSTS WERE AROUND 22 MPH
ACROSS THE U.S. VIRGIN ISLANDS.
A SURFACE HIGH PRESSURE OVER THE SOUTHWESTERN ATLANTIC WILL CONTINUE
TO PROMOTE NORTHEASTERLY WINDS AND COLD AIR ADVECTION ACROSS THE
NORTHEASTERN CARIBBEAN THROUGH AT LEAST WEDNESDAY. A MID-TO UPPER-
LEVEL RIDGE EXTENDING FROM THE WESTERN CARIBBEAN WILL ALSO CONTINUE
PROVIDE DRIER AIR ALOFT AND PROMOTE WARMING OF THE 500 MB
TEMPERATURES THROUGH THE SAME PERIOD. THE PRECIPITABLE WATER CONTENT
IS EXPECTED TO REMAIN BELOW NORMAL LEVELS DURING THE NEXT 48 HOURS
OR SO. HOWEVER, MOISTURE ADVECTION WILL GRADUALLY INCREASE FROM THE
CARIBBEAN WATERS/ANEGADA PASSAGE BY THE END OF THE SHORT-TERM PERIOD
AS THE SURFACE HIGH MOVES FURTHER EAST INTO THE CENTRAL ATLANTIC,
AND WINDS TURN FROM THE EAST TO SOUTHEAST, BRINGING THE REMNANTS OF
THE OLD FRONTAL BOUNDARY ACROSS THE LOCAL AREA. THEREFORE, SHOWER
ACTIVITY WILL INCREASE IN GENERAL OVER THE USVI BY THURSDAY.
HIGH TEMPERATURES WILL BE IN THE THE MID 80S ACROSS MOST COASTAL
AREAS OF THE ISLANDS, EXCEPT IN SOUTHERN PR WHERE IT CAN REACH THE
LOW 90S ONCE AGAIN ON WEDNESDAY, WHILE THE MINIMUM TEMPERATURES
COULD DROP INTO THE UPPER 50S AND LOW 60S ACROSS THE HIGHER
ELEVATIONS AND MOUNTAIN VALLEYS.
LONG TERM...FRIDAY THROUGH TUESDAY
..FROM PREVIOUS DISCUSSION ISSUED AT 351 AM TUES NOV 19 2024
A HIGH PRESSURE SYSTEM OVER THE EASTERN ATLANTIC AND A POLAR
TROUGH EXITING THE EASTERN COAST OF THE UNITED STATES WILL SWITCH
THE WINDS FROM THE SOUTH FOR THE END OF THE WEEK. THE PRESSURE
GRADIENT WILL WEAKEN TOO, MEANING THAT THE WIND FLOW WILL BE
LIGHT. UNDER THIS FLOW, MOISTURE WILL BE PULLED FROM THE CARIBBEAN
SEA INTO THE ISLANDS, INCREASING THE POTENTIAL FOR SHOWERS AND
THUNDERSTORMS. THIS WILL ELEVATE THE RISK OF FLOODING FOR THE
ISLANDS THROUGH THE WEEKEND. THEN, EARLY NEXT WEEK, THE RIDGE WILL
REBUILD, BUT PRECIPITABLE WATER VALUES WILL REMAIN ABOVE NORMAL.
THE TRADE WINDS WILL RECOVER TOO, COMING FROM THE EAST AROUND 15
KNOTS. UNDER THIS FLOW, PATCHES OF LOW-LEVEL CLOUDS WILL STILL
REACH THE ISLANDS, WITH PASSING SHOWERS ACTIVITY FOR EASTERN
PUERTO RICO AND THE VIRGIN ISLANDS.
AVIATION
(18Z TAFS)
MAINLY VFR CONDITIONS ARE EXPECTED TO PREVAIL ACROSS ALL TERMINALS
DURING THE NEXT 24 HOURS. THE 19/12Z TJSJ SOUNDING INDICATED NE
WINDS UP TO 12 KNOTS BLO FL050.
MARINE
A BROAD SURFACE HIGH PRESSURE OVER THE WESTERN ATLANTIC EXTENDING
INTO THE CENTRAL ATLANTIC WILL CONTINUE TO PROMOTE A GENTLE TO
MODERATE NORTHERLY WINDS THROUGH LATE WEDNESDAY. ANOTHER PULSE OF
THE NORTHERLY SWELL WILL ARRIVE TOMORROW, BUT CONDITIONS ARE
LIKELY TO REMAIN BELOW SMALL CRAFT ADVISORY CRITERIA. ANOTHER
SMALL LONG- PERIOD NORTHERLY SWELL IS EXPECTED FOR THE WEEKEND.
BEACH FORECAST
THERE IS A MODERATE RISK OF RIP CURRENTS ACROSS THE NORTHERN
COASTAL AREAS OF PUERTO RICO AND THE U.S. VIRGIN ISLANDS. THERE
IS ANOTHER PULSE OF NORTHERLY SWELL THAT COULD ARRIVE BY THURSDAY,
INCREASING THE RISK TO HIGH AGAIN.
SJU WATCHES/WARNINGS/ADVISORIES
PR...NONE.
VI...NONE.
AM...NONE.
SHORT TERM & AVIATION...DS
MARINE....LIS
CLICK HERE TO GO TO PREVIOUS BULLETINS.
Main Text Page