672
FXCA20 KWBC 041900
PMDCA
TROPICAL DISCUSSION - INTERNATIONAL DESKS
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
259 PM EDT FRI OCT 04 2024
FORECAST BULLETIN 04 OCT 2024 AT 1900 UTC:
THE NATIONAL HURRICANE CENTER (NHC) CONTINUES TO ISSUE ADVISORIES
ON HURRICANE KIRK AND TROPICAL STORM LESLIE IN THE ATLANTIC
WATERS. THERE ARE ALSO TWO AREAS OF POSSIBLE TROPICAL CYCLONE
DEVELOPMENT OVER THE NEXT 7 DAYS...ONE OF THEM IS IN THE GULF OF
MEXICO AND THE OTHER IS IN THE EAST PACIFIC...OFF THE COAST OF
SOUTHWESTERN MEXICO. ACCORDING TO THE LATEST NHC OUTLOOK...BOTH OF
THOSE AREAS HAVE A LOW CHANCE OF TROPICAL CYCLONE FORMATION
THROUGH 48 HOURS...AND A MEDIUM PERCENT CHANCE OF FORMATION
THROUGH 7 DAYS. PLEASE SEE THE LATEST ADVISORIES AND OUTLOOKS
ISSUED BY THE NHC AT WWW.HURRICANES.GOV.
ACROSS THE TROPICAL REGION...OTHER THAN THE TROPICAL CYCLONES KIRK
AND LESLIE...THERE IS AN EXTRA-TROPICAL LOW PRESSURE NEAR 33N/60W
THAT IS CAUSING NORTHERLY WINDS AND BRINGING DRIER AIR INTO THE
BAHAMAS TODAY. THIS LOW PRESSURE IS FORECAST TO MEANDER OVER THE
AREA THROUGH THE NEXT FEW DAYS AS IT WEAKENS. THERE IS ALSO A
TROUGH OF LOW PRESSURE ACROSS THE WESTERN GULF OF MEXICO...WHICH
HAS THE POTENTIAL OF DEVELOPING A BROAD CIRCULATION OVER THE NEXT
FEW DAYS AS IT SLOWLY MOVES INTO THE CENTRAL GULF OF MEXICO. THERE
IS ALSO AN AREA OF LOW PRESSURE JUST SOUTH OF SOUTHWESTERN
MEXICO...WHICH IS FORECAST TO DEEPEN AND MOVE WEST NORTHWEST
OFFSHORE OF SOUTHWESTERN MEXICO OVER THE NEXT SEVERAL DAYS. THESE
LOW PRESSURES WILL CAUSE SHOWERS AND THUNDERSTORMS TO AFFECT
PORTIONS OF THE GULF COAST OF MEXICO FROM VERACRUZ TO THE YUCATAN
PENINSULA...AS WELL AS THE PACIFIC COAST OF MEXICO...FROM GUERRERO
TO JALISCO.
THERE ARE A FEW FEATURES OF INTEREST IN THE MID LEVELS ACROSS THE
TROPICAL REGION. A MID LEVEL LOW ASSOCIATED WITH THE EXTRA
TROPICAL LOW EXTENDS SOME TROGHINESS TO THE SOUTHWEST INTO THE
TURKS AND CAICOS. THIS MID LEVEL TROUGH OVER THE AREA WILL LIFT BY
LATE SUNDAY AS THE MID LEVEL LOW MOVES EAST. THERE IS A BROAD MID
LEVEL HIGH ACROSS THE WESTERN CARIBBEAN...ENCOMPASSING A LARGE
AREA OF THE CARIBBEAN AND INTO CENTRAL AMERICA...PROVIDING
SUBSIDENCE. HOWEVER...THERE IS A MID LEVEL LOW DEVELOPING WITH
LOCALLY HIGHER VORTICITY ACROSS THE WESTERN TO SOUTHWESTERN GULF
OF MEXICO...ASSOCIATED WITH THE DEVELOPING LOW OVER THE AREA...AND
THERE IS ALSO A MID LEVEL LOW OVER NORTHERN MEXICO...WHICH COULD
PROVIDE INSTABILITY AND PROMOTE CONVECTION OVER PORTIONS OF
WESTERN AND SOUTHERN MEXICO...AS IT COMBINES WITH THE DEEPER
MOISTURE AND THE LOW LEVEL FEATURES IN THE GULF AND EASTERN
PACIFIC. IN THE UPPER LEVELS...THERE IS A TROUGH THAT ALSO EXTENDS
FROM THE WEST CENTRAL ATLANTIC INTO THE TURKS AND CAICOS...WITH AN
INVERTED TROUGH AXIS OVER HISPANIOLA AND INTO THE SOUTHERN
CARIBBEAN. THIS UPPER TROUGH IS EXPECTED TO MOVE EAST THROUGH THE
WEEKEND AS IT WEAKENS. AN UPPER LEVEL HIGH PRESSURE IS DOMINATING
THE GULF OF MEXICO INTO THE WESTERN CARIBBEAN...AND IS EXPECTED TO
ELONGATE NORTHEAST INTO THE BAHAMAS...BUT PREVAIL THROUGH THE
WEEKEND. AN UPPER RIDGE IS ALSO FORECAST ACROSS THE EASTERN
CARIBBEAN. HOWEVER...A WEAK UPPER TROUGH IS FORECAST TO HAVE ITS
AXIS OVER NORTH CENTRAL MEXICO THIS WEEKEND...WHICH WILL HELP
PROMOTE INSTABILITY OVER PORTIONS OF THE SOUTHERN HALF OF
MEXICO...ESPECIALLY AFTER CONSIDERING THE MID LEVEL TROUGH AND LOW
LEVEL FEATURES IN THE AREA. OVERALL...THE GENERAL SYNOPTIC PATTERN
IS CONDUCIVE FOR SOME ENHANCED CONVECTION OVER PORTIONS OF
SOUTHERN MEXICO INTO NORTHERN CENTRAL AMERICA...WHILE THE
CARIBBEAN...THE BAHAMAS...AND THE SOUTHERN HALF OF CENTRAL AMERICA
COULD EXPECT RELATIVELY MODEST AMOUNTS OF RAIN THROUGH THE
WEEKEND.
THE SYNOPTIC SITUATION OVER NORTHERN SOUTH AMERICA IS
UNIMPRESSIVE...BUT LARGE AREAS WITH SOME SHOWERS AND THUNDERSTORMS
ARE EXPECTED EACH DAY...HOWEVER. THERE ARE A FEW SFC TROUGHS
MOVING THROUGH THE AREA...BUT THE MID AND UPPER LEVEL WINDS AND
HEIGHTS ARE NOT VERY CONDUCIVE FOR PROLONGED AND ENHANCED
CONVECTION. THIS IS BECAUSE THERE IS A BROAD MID LEVEL HIGH
PRESSURE OVER CENTRAL SOUTH AMERICA...CAUSING RELATIVELY LIGHT
EASTERLY WINDS OVER NORTHERN SOUTH AMERICA. THE UPPER LEVELS WILL
ALSO PROVIDE PREVAILING EASTERLY WINDS...NOT VERY CONDUCIVE TO
ENHANCED CONVECTION...WITH THE EXCEPTION OF SOME DIVERGENCE. THAT
BEING SAID...THE AVAILABLE MOISTURE AND DIURNAL HEATING...COMBINED
WITH THE SFC TROUGHS MOVING THROUGH WILL BE ENOUGH TO CAUSE
DIURNAL CONVECTION OVER THE AREA. THE EGDI ALGORITHM ALSO SUGGESTS
LARGE AREAS WITH THUNDERSTORM POTENTIAL...ESPECIALLY OVER
NORTHWESTERN BRAZIL TO THE NORTHWEST OF THE CONTINENT. ONE THING
TO NOTE...IS THAT A PERSISTENT AND LONG FETCH LOW LEVEL WIND FLOW
INTO WESTERN COLOMBIA IS EXPECTED THROUGH THE WEEKEND. THIS
ONSHORE FLOW WILL CAUSE THE DEVELOPMENT OF SHOWERS AND
THUNDERSTORMS ACROSS WESTERN COLOMBIA AS THE MOISTURE INTERACTS
WITH THE OROGRAPHIC LIFTING.
IN TERMS OF RAINFALL OVER THE REGION THROUGH THE WEEKEND...THE
AREAS WITH THE HIGHEST RAINFALL POTENTIAL ARE PORTIONS OF THE
SOUTHERN HALF OF MEXICO INTO GUATEMALA...AND NORTHWESTERN SOUTH
AMERICA...FROM NORTHWEST BRAZIL TO WESTERN COLOMBIA...GIVEN THE
AFOREMENTIONED SYNOPTIC PATTERNS. THE AMOUNTS OF RAIN IN THE
FORECAST OVER MEXICO HAVE A HIGHER UNCERTAINTY THEN
NORMAL...CONSIDERING THAT THE MODEL GUIDANCE IS IN SOME
DISAGREEMENT...AND THAT SOME OF THE RAINFALL WILL DEPEND ON THE
EVENTUAL DEVELOPMENT OF THE LOW PRESSURES IN THE GULF OF MEXICO AS
WELL AS THE EASTERN PACIFIC ALONG THE SOUTHWESTERN MEXICAN COAST.
IN THE CARIBBEAN...THE LESSER ANTILLES ARE FORECAST LITTLE TO NO
RAINFALL ACCUMULATIONS THROUGH THE WEEKEND...WHILE THE GREATER
ANTILLES ARE FORECAST MINOR ACCUMULATIONS THROUGH MOST OF THE
DAY...BUT AFTERNOON CONVECTION MAY CAUSE LOCALIZED PRECIPITATION
THAT COULD REACH 25 TO 35MM. WESTERN CUBA DOES HAVE A HIGHER
CHANCE OF RAIN...UP TO 50MM TODAY INTO SATURDAY MORNING AS A
TROUGH WITH THUNDERSTORM ACTIVITY MOVES OVER THE AREA...THEN
SATURDAY AND SUNDAY WILL HAVE LOCALIZED CONVECTION. CENTRAL
AMERICA...GENERALLY FROM HONDURAS SOUTHWARD TO PANAMA WILL HAVE
MODELS AMOUNTS OF RAIN EACH DAY THROUGH THE WEEKEND. THE FORECAST
IS FOR MAX DAILY RAIN OF UP TO 35MM...THOUGH MOST OF THE AREA IS
FORECAST MAX DAILY RAINFALL OF 25MM OR LESS.
ALAMO...(WPC)
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