100
FXCA20 KWBC 211842
PMDCA
TROPICAL DISCUSSION - INTERNATIONAL DESKS
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
242 PM EDT MON OCT 21 2024
FORECAST BULLETIN 21 OCT 2024 AT 1900 UTC:
THE MADDEN-JULIAN OSCILLATION CONTINUES ORGANIZING...AND CURRENT
MODEL ANALYSIS SHOW A WELL DEFINED WAVE-ONE PATTERN ACROSS THE
GLOBE. ENHANCED UPPER CONVERGENCE IS FORECAST TO CONTINUE
EXTENDING ACROSS THE AMERICAS THROUGH NEXT WEEK. THIS WILL LIKELY
LIMIT THE COVERAGE OF HEAVY RAIN PRODUCING SYSTEMS THROUGH THE
FORECAST CYCLE.
A SYSTEM OF INTEREST IS TROPICAL STORM OSCAR. AT 15 UTC...TROPICAL
STORM OSCAR CENTERED NEAR 20.3N 75.4W. MINIMUM CENTRAL PRESSURE
WAS ESTIMATED AT 1001 HPA AND MAXIMUM SUSTAINED WINDS AT 35KT WITH
GUSTS UP TO 45KT. OSCAR WAS MOVING TO THE WEST NORTHWEST OR AT 300
DEGREES AND AT 03KT. PLEASE FOLLOW NHC GUIDANCE FOR UPDATES ON
OSCAR. REGARDING RAINFALL IMPACTS IN OUR FORECAST AREA...OSCAR IS
EXPECTED TO FAVOR LOCALLY HEAVY RAINFALL IN FAR SOUTHEAST CUBA AND
THE SOUTHEAST BAHAMAS AND TURKS AND CAICOS THROUGH EARLY WEDNESDAY
TO THEN MOVE AWAY FROM THE ISLANDS INTO THE NORTH ATLANTIC.
THROUGH EARLY TUESDAY OSCAR WILL FAVOR TOTALS O0F 25-50MM/DAY AND
MAXIMA OF 100-200MM IN FAR SOUTHEAST CUBA DUE TO TERRAIN
ENHANCEMENT. IN THE SOUTHEAST BAHAMAS EXPECT MAXIMA OF 25-50MM
WHILE IN THE TURKS AND CAICOS EXPECT MAXIMA OF 20-45MM. ALSO LATE
ON MONDAY/EARLY TUESDAY...ONSHORE SOUTHERLY FLOW ACROSS THE
HAITIAN PENINSULA WILL TRIGGER 15-20MM/DAY AND ISOLATED MAXIMA OF
25-50MM. ON TUESDAY THROUGH EARLY WEDNESDAY...OSCAR WILL FAVOR
15-20MM/DAY AND MAXIMA OF 35-70MM IN THE SOUTHEAST BAHAMAS...AND
MAXIMA OF 20-35MM IN THE TURKS AND CAICOS AND INAGUA. SOUTHERLY
FLOW WILL FAVOR MAXIMA OF 15-30MM ALONG THE SOUTHERN TIER OF
HISPANIOLA. AFTER THIS PERIOD...THE EFFECTS OF OSCAR ON
PRECIPITATION WILL REMAIN MOSTLY OFFSHORE IN THE NORTH ATLANTIC.
ANOTHER REGION WHERE MODERATE PRECIPITATION IS POSSIBLE IS
SOUTHERN MEXICO AND NORTHERN CENTRAL AMERICA. HERE...HEAVY
RAINFALL CONTINUES TO DEVELOP IN ASSOCIATION WITH LONG FETCH
NORTHEASTERLY WINDS ACROSS THE GULF OF HONDURAS/GULF OF MEXICO
INTERACTING WITH TERRAIN. THE STRONGEST OROGRAPHIC ENHANCEMENT IS
EXPECTED TO CONTINUE ACROSS NORTHERN OAXACA AND SOUTHERN
VERACRUZ...WHERE ENHANCED ONSHORE FLOW WILL FAVOR 20-40MM/DAY AND
MAXIMA OF 75-125MM THROUGH EARLY TUESDAY. FROM CHAIPAS/TABASCO
INTO NORTHWEST HONDURAS AND BELIZE EXPECT 15-20MM/DAY AND MAXIMA
OF 30-60MM THROUGH EARLY TUESDAY. ON NORTHERN VERACRUZ/NORTHERN
PUEBLA AND HIDALGO EXPECT MAXIMA OF 20-45MM. ON TUESDAY...AS
NORTHEASTERLY LOW-LEVEL WINDS LOSE MOMENTUM EXPECT AMOUNTS TO
DECREASE TO 10-15MM/DAY AND MAXIMA OF 20-35MM FROM NORTHWEST
HODNURAS INTO SOUTH-CENTRAL VERACRUZ. THIS DECREASES FURTHERMORE
THEREAFTER. ELSEWHERE IN MEXICO...DIURNAL CONVECTION WILL CLUSTER
IN PORTIONS OF THE SIERRA MADRE DEL SUR AND FAR SOUTHWEST
MEXICO...ALTHOUGH EXPECT MAXIMA TO REMAIN ISOLATED AND UNDER THE
15-25MM/DAY RANGE.
SEASONAL CONVECTION IS EXPECTED IN NORTHWEST SOUTH AMERICA AND
SOUTHERN CENTRAL AMERICA...FROM COLOMBIA INTO COSTA RICA AND
PANAMA. HOWEVER...UPPER CONVERGENT MJO CONDITIONS WILL LIKELY
LIMIT THE COVERAGE OF THE REGIONS OF HEAVIEST RAINFALL. IN PANAMA
AND COSTA RICA...MOST ACTIVITY WILL ORGANIZE WITH ITCZ/MONSOON
TROUGH CONVERGENCE AIDED BY WESTERLY FLOW IN THE PACIFIC BASINS.
THIS WILL FAVOR AMOUNTS OF 10-15MM/DAY AND MAXIMA OF 20-35MM ON
MONDAY AND TUESDAY...DECREASING TO MAXIMA OF 15-25MM ON WEDNESDAY.
TO THE EAST...AN UPPER LOW IS PRESENT OVER NORTHEAST SOUTH
AMERICA...AND IS FORECAST TO GRADUALLY MEANDER WESTWARD WHILE
WEAKENING. THIS WILL MAINTAIN ACTIVE CONVECTION IN COLOMBIA
THROUGH THE FORECAST CYCLE...YIELDING TO AN INCREASING TREND IN
WESTERN COLOMBIA THROUGH WEDNESDAY. ON MONDAY...EXPECT MAXIMA OF
20-45MM IN MOST OF NORTHERN AND WESTERN COLOMBIA. ON TUESDAY
EXPECT MAXIMA GENERALLY IN THE 20-35MM/DAY RANGE...HOWEVER EXPECT
LOCAL MAXIMA OF 30-60MM IN THE VALLE DEL CAUCA REGION. ON
WEDNESDAY...EXPECT MAXIMA OF 30-60MM DEVELOPING FROM THE CENTRAL
CHOCO INTO COASTAL NARINO IN SOUTHWEST COLOMBIA...WHILE EXPECT
MAXIMA OF 20-45MM IN THE ANDEAN REGION. THE UPPER LOW WILL ALSO
FAVOR AN INCREASE IN ACCUMULATION ACROSS THE AMAZON BASIN IN
COLOMBIA...WHERE EXPECT 10-15MM/DAY AND MAXIMA OF 20-45MM ON
WEDNESDAY THROUGH EARLY THURSDAY.
IN THE CARIBBEAN...ASIDE FROM TROPICAL STORM OSCAR...EXPECT
ACTIVITY TO RESPOND TO THE INFLUENCE OF AN EASTERLY WAVE CROSSING
THE LESSER ANTILLES ON TUESDAY (SEE BELOW). NEVERTHELESS...A
TROUGH PROPAGATING AHEAD OF THE MAIN WAVE WILL LIKELY ENTER THE
WINDWARD ISLANDS LATER ON MONDAY...TO FAVOR MAXIMA OF 20-35MM.
EASTERLY/TROPICAL WAVES INITIALIZED AT 12 UTC
TYPE SOF INT 22/00 22/12 23/00 23/12 24/00 24/12 25/00 25/12
TW 13N 33W 36W 39W 43W 46W 50W 53W 57W 60W
EW 20N 51W 53W 56W 58W 60W DISS
A TROPICAL WAVE IS INITIALIZED AT 33W AND SOUTH OF 13N. THIS WAVE
IS FORECAST TO AMPLIFY AND DEVELOP AN INCREASE IN THE COVERAGE OF
CONVECTION AS IT ENTERS THE GUIANAS ON THURSDAY. IT WILL LIKELY
PRODUCE MODERATE PRECIPITATION IN THE WINDWARD ISLANDS ON FRIDAY.
AN EASTERLY WAVE IS INITIALIZED AT 51W AND SOUTH OF 20N. THIS WAVE
IS FORECAST TO PROPAGATE INTO THE LESSER ANTILLES LATE ON TUESDAY.
HOWEVER...AS AN UPPER TROUGH DEEPENS TO THE NORTH OF THE GREATER
ANTILLES...EXPECT THIS WAVE TO START LOSING DEFINITION LATE ON
TUESDAY WHILE MEANDERING NORTHWARD ACROSS THE LEEWARD ISLANDS. IN
THE MEAN TIME...EXPECT THIS WAVE TO FAVOR MAXIMA OF 15-30MM ACROSS
THE LESSER ANTILLES AND NORTHEAST VENEZUELA ON TUESDAY.
GALVEZ...(WPC)
JACKMAN...(BMS BARBADOS)
MATHIAS...(CIAARA-MB BRASIL)
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