345
FXCA62 TJSJ 182016
AFDSJU
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN JUAN PR
416 PM AST MON NOV 18 2024
SYNOPSIS
A MORE STABLE WEATHER PATTERN IS FORECASTED FOR THE NEXT FEW DAYS
AS A DRIER AIRMASS HOLDS IN PLACE DUE TO A STRONG SURFACE RIDGE
UNTIL THURSDAY. BY LATE THURSDAY INTO THE WEEKEND, WINDS WILL
RETURN FROM THE EAST-SOUTHEAST, INCREASING THE TROPICAL MOISTURE
AGAIN AND ENHANCING MORE SHOWERS ACROSS THE LOCAL REGION.
HAZARDOUS MARINE AND COASTAL CONDITIONS WILL PERSIST FOR THE REST
OF THE DAY INTO TOMORROW, WHERE A HIGH RISK OF RIP CURRENTS WILL
REMAIN IN EFFECT FOR MOST OF THE NORTHERN EXPOSED BEACHES OF
PUERTO RICO. FOR MORE DETAILED INFORMATION, VISIT
WWW.WEATHER.GOV/SJU/MARINE.
SHORT TERM...TODAY THROUGH WEDNESDAY
MOSTLY SUNNY SKIES PREVAILED ACROSS THE SOUTHERN COAST OF PR DURING
THE MORNING HOURS, WHILE MOSTLY CLOUDY WITH LIGHT SHOWERS PREVAILED
ACROSS PORTIONS OF THE NORTHERN HALF OF PR AND ACROSS THE U.S.
VIRGIN ISLANDS. HIGH TEMPERATURES WERE IN THE MID 80S ACROSS MOST
LOWER ELEVATIONS, EXCEPT IN SOUTHERN PR WHERE TEMPERATURES REACHED
THE LOW 90S. THE WIND WAS FROM THE NORTH BETWEEN 8 AND 12 MPH WITH
GUSTS BETWEEN 22 AND 28 MPH, MAINLY ACROSS COASTAL AREAS.
A BUILDING SURFACE HIGH PRESSURE OVER THE WEST/SOUTHWESTERN ATLANTIC
WILL PROMOTE NORTHERLY WINDS AND COOLER AIR ADVECTION ACROSS THE
NORTHEASTERN CARIBBEAN THROUGH THE SHORT-TERM PERIOD. MID-LEVEL
DRIER AIR WILL ALSO FILTER OVER THE LOCAL AREA AND THE PRECIPITABLE
WATER CONTENT IS EXPECTED TO REMAIN BELOW NORMAL LEVELS. HOWEVER,
JUST SOUTHEAST OF ST. CROIX THE REMNANTS OF FRONTAL BOUNDARY WILL
LINGER THROUGH MIDWEEK, AND SOME SHOWERS COULD MOVE AT TIMES OVER
LAND AREAS. IN ADDITION, THE 500 MB TEMPERATURES WILL ALSO WARM UP,
LIMITING THE DEVELOPMENT OF THUNDERSTORM ACTIVITY DURING THE
AFTERNOON HOURS. IN GENERAL, THE LIMITED AVAILABLE LOW-LEVEL
MOISTURE CONTENT WILL COMBINE WITH LOCAL EFFECTS TO TRIGGER SHOWER
DEVELOPMENT MAINLY OVER THE CORDILLERA CENTRAL EACH AFTERNOON. HIGH
TEMPERATURES SHOULD REACH THE MID 80S ACROSS MOST COASTAL AREAS OF
THE ISLANDS EACH DAY, EXCEPT IN SOUTHERN PR WHERE IT CAN EXPERIENCE
THE LOW 90S DUE TO THE SOUTHERLY COMPONENT OF THE SEA BREEZE.
LONG TERM...THURSDAY THROUGH MONDAY
..FROM PREVIOUS DISCUSSION ISSUED 426 MON NOV 18, 2024
THE WEATHER PATTERN WILL SHIFT TO A WETTER ONE ONCE AGAIN. AS A
SURFACE TO MID-LEVEL HIGH BUILDS WEST OVER THE EASTERN ATLANTIC,
THE WIND FLOW WILL SHIFT WILL GAIN A MORE SOUTHERLY COMPONENT,
PULLING MOISTURE FROM THE CARIBBEAN INTO THE REGION. SO FAR, THE
GLOBAL GUIDANCE INDICATE THAT THE BULK OF THE MOISTURE WILL MOVE
CLOSER TO THE DOMINICAN REPUBLIC, BUT PRECIPITABLE WATER SHOULD
STILL GO ABOVE NORMAL FROM THURSDAY THROUGH SATURDAY. THIS WILL
BRING AN INCREASE IN SHOWERS AND THUNDERSTORMS FOR THE ISLANDS,
INCREASING THE RISK FOR FLOODING. ALSO, UNDER A DEEP-LAYERED
SOUTHERLY FLOW, TEMPERATURES WILL SOAR ONCE AGAIN, AND THE WARMER
THAN NORMAL HEAT WILL RETURN, EXCEPT ON AREAS WHERE THE CLOUD DECK
REMAINS THICK ENOUGH. FOR SUNDAY, A POCKET OF DRIER AIR WILL MOVE
IN, GIVING THE ISLANDS A BREAK FROM THE WET PATTERN, BUT IT LOOKS
LIKE ANOTHER SURGE OF MOISTURE WILL APPROACH FROM THE EAST EARLY
NEXT WEEK, WITH ANOTHER ROUND OF RAIN FOR THE EASTERN CARIBBEAN.
AVIATION
(18Z TAFS)
MAINLY VFR CONDITIONS ARE EXPECTED TO PREVAIL ACROSS ALL TERMINALS
DURING THE NEXT 24 HOURS. HOWEVER, MOSTLY VCSH AND SCT/BKN CIGS BTW
FL040-070 DUE TO FROPA EXPECTED ACROSS THE LOCAL AREA. THE 18/12Z
TJSJ SOUNDING INDICATED NORTH WINDS UP TO 12 KNOTS BLO FL050.
MARINE
A STRONG BROAD BUILDING SURFACE HIGH PRESSURE OVER THE WESTERN
ATLANTIC AND A STATIONARY FRONTAL BOUNDARY SOUTH OF THE CWA WILL
MAINTAIN A MODERATE NORTHEASTERLY WIND FLOW. THIS PATTERN WILL
HOLD MOST SEAS UP TO 5 FEET ACROSS MOST OF THE LOCAL WATERS.
ANOTHER NORTHERLY SWELL WAS GENERATED BY A SURFACE LOW AT THE
NORTH OF THE ATLANTIC, INCREASING ONCE AGAIN THE SEAS AND TURNING
HAZARDOUS THE MARINE CONDITIONS FOR THE MARINERS.
BEACH FORECAST
A SUBSIDING NORTHERLY SWELL WILL MAINTAIN HAZARDOUS COASTAL
CONDITIONS FOR AT LEAST TOMORROW. THEREFORE, RIP CURRENT HAS A
HIGH RISK ACROSS THE NORTHERN EXPOSED COASTAL AREAS. COASTAL
CONDITIONS WILL IMPROVE BY LATE TUESDAY, BUT FOR WEDNESDAY
AFTERNOON, WHEN ANOTHER LONG PERIOD OF NORTHERLY SWELL RESULTS
FROM A SURFACE LOW OVER THE NORTHERN ATLANTIC, THE WAVES WILL
INCREASE ONCE AGAIN, ONCE AGAIN BREAKING ALONG THE COASTAL AREAS.
SJU WATCHES/WARNINGS/ADVISORIES
PR...HIGH RIP CURRENT RISK THROUGH LATE TONIGHT FOR PRZ001-002-005-
008-010-012-013.
VI...HIGH RIP CURRENT RISK THROUGH LATE TONIGHT FOR VIZ001.
AM...NONE.
SHORT TERM...DS
LONG TERM....LIS
AVIATION...DS
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