917
FXCA20 KWBC 191812
PMDCA
TROPICAL DISCUSSION - INTERNATIONAL DESKS
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
212 PM EDT TUE SEP 19 2023
FORECAST BULLETIN 19 SEP 2023 AT 1830 UTC: OF NOTE...CFS FORECASTS
ARE INDICATING THAT A KELVIN WAVE IS PROPAGATING OVER THE REGION
FOR THE FORECAST PERIOD. THE MJO IS CURRENTLY IN A CONVERGENT
PHASE...AND THE PASSING OF THE KELVIN WAVE WILL PROVIDE MARGINAL
ENHANCEMENT IN CONVECTION.
A ROBUST HIGH PRESSURE SYSTEM EXTENDS OVER THE SOUTHWEST UNITED
STATES AND INTO MEXICO AND GUATEMALA/BELIZE ON TUESDAY. MOISTURE
CONVERGENCE ALONG THE SIERRA MADRE OCCIDENTAL...AND THE PASSING OF
AND EASTERLY WAVE WILL BE THE MAIN PRODUCERS OF PRECIPITATION. THE
HIGH PRESSURE SYSTEM ALOFT IS EXPECTED TO CONTINUE PROVIDING
UNFAVORABLE CONDITIONS FOR DEEP CONVECTION AND PRECIPITATION
VALUES ARE EXPECTED TO REMAIN BELOW 35MM THROUGHOUT THE FORECAST
PERIOD...WITH SOME LOCALIZED HIGHER AMOUNTS POSSIBLE. ANOTHER
EASTERLY WAVE IS FORECAST TO ENTER THE YUCATAN PENINSULA ON
THURSDAY. ON TUESDAY...EXPECT MAXIMA OF 20-35MM ALONG THE SIERRA
MADRE OCCIDENTAL AND INTO NAYARIT AND WESTERN JALISCO. ELSEWHERE
IN SOUTHERN MEXICO...EXPECT ISOLATED MAXIMA BETWEEN 15-25MM. ON
WEDNESDAY...SONORA...CHIHUAHUA...AND NORTHERN SINALOA CAN EXPECT
MAXIMA OF 20-35MM. ALONG THE SIERRA MADRE DEL SUR AND CHIAPAS AND
TABASCO EXPECT MAXIMA OF 15-25MM. ON THURSDAY...THE EASTERLY WAVE
ENTERING THE YUCATAN PENINSULA WILL FAVOR MAXIMA OF 15-25MM IN THE
YUCATAN AND INTO CHIAPAS AND TABASCO. SIMILAR ISOLATED AMOUNTS ARE
EXPECTED IN SOUTHERN VERACRUZ...OAXACA...AND ALONG WESTERN MEXICO.
OVER THE CARIBBEAN...A SURFACE FRONTAL BOUNDARY IS LOCATED ALONG
THE EASTERN SEABOARD OF THE UNITED STATES...ENTERS FLORIDA...AND
INTO THE NORTHERN GULF OF MEXICO. THE BOUNDARY BECOMES STATIONARY
NORTH OF THE BAHAMAS...BUT A PREFRONTAL TROUGH EXTENDS INTO
CENTRAL BAHAMAS AND CUBA...WHICH WILL FAVOR PRECIPITATION FOR THE
NEXT FEW DAYS. A TROUGH ALOFT EXTENDS OVER THE CARIBBEAN AND INTO
NORTHEAST CENTRAL AMERICA AND THE CENTRAL CARIBBEAN SEA. IT WILL
PRODUCE SHORT WAVE TROUGHS THAT WILL FAVOR ISOLATED HEAVY AMOUNTS
IN AREAS OF THE CARIBBEAN. THE EFFECTS OF THE TROUGH ALOFT AND THE
SURFACE FRONT ARE EXPECTED THROUGHOUT THE FORECAST PERIOD. ALONG
THE LESSER ANTILLES...A TROPICAL WAVE IS APPROACHING AND BRINGING
HIGHER AMOUNTS OF PRECIPITABLE WATER. THE WAVE MOVES WEST AND IS
EXPECTED TO BRING PRECIPITATION TO THE AREA. ON TUESDAY...WEST
HISPANIOLA CAN EXPECT MAXIMA OF 20-45MM. NORTHERN BAHAMAS AND EAST
CUBA ARE FORECAST MAXIMA OF 20-35MM. THE REST OF THE GREATER
ANTILLES CAN EXPECT MAXIMA OF 15-25MM...WITH ISOLATED HEAVIER
AMOUNTS POSSIBLE. ON WEDNESDAY...NORTHERN BAHAMAS AND CENTRAL-EAST
CUBA CAN EXPECT MAXIMA OF 20-45MM...WHILE THE LESSER ANTILLES SEE
THE ARRIVAL OF THE TROPICAL WAVE FAVORING SIMILAR AMOUNTS. THE
CENTRAL BAHAMAS ARE FORECAST MAXIMA OF 20-35MM...WHILE THE REST OF
THE GREATER ANTILLES ARE FORECAST MAXIMA UNDER 25MM. ON
THURSDAY...MOISTURE FROM THE PASSING TROPICAL WAVE WILL FAVOR
MAXIMA OF 20-35MM IN THE LESSER ANTILLES...AND MAXIMA OF 15-25MM
IN PUERTO RICO AND THE VIRGIN ISLANDS. EFFECTS OF THE PREFRONTAL
TROUGH IN NORTHERN BAHAMAS WILL FAVOR MAXIMA OF 20-45MM...WHILE
CENTRAL-EAST CUBA IS FORECAST MAXIMA OF 20-35MM. ELSEWHERE OVER
THE GREATER ANTILLES EXPECT MAXIMA OF 15-25MM.
IN CENTRAL AMERICA...THE AFOREMENTIONED UPPER LEVEL TROUGH HAS ITS
BASE IN EASTERN NICARAGUA AND HONDURAS ON TUESDAY. IN THE LOWER
LEVELS...AN EASTERLY WAVE IS LOCATED OVER PANAMA AND PRECIPITABLE
WATER VALUES EXCEEDING 55MM. DUE TO ITS CIRCULATION AND THE
EASTERLY TRADE WINDS...THE WAVE WILL FAVOR ONSHORE FLOW AND
MOISTURE CONVERGENCE IN COSTA RICA AND PANAMA...WHERE CONSIDERABLE
AMOUNTS OF PRECIPITATION ARE EXPECTED. AS THE WAVE MOVES
WESTWARD...THE REST OF CENTRAL AMERICA IS EXPECTED TO MODERATE
AMOUNTS OF PRECIPITATION THROUGHOUT THE FORECAST PERIOD. ON
WEDNESDAY...SOUTHERN COSTA RICA IS FORECAST MAXIMA OF
30-60MM...WHILE PANAMA CAN EXPECT MAXIMA OF 20-45MM. EASTERN
NICARAGUA AND NORTHERN COSTA RICA ARE FORECAST MAXIMA OF 20-35MM.
ELSEWHERE IN NORTHERN CENTRAL AMERICA EXPECT ISOLATED MAXIMA OF
15-25MM. ON WEDNESDAY...THE WAVE WILL FAVOR MAXIMA OF 35-70MM IN
NICARAGUA AND WEST EL SALVADOR. COSTA RICA AND WESTERN PANAMA ARE
FORECAST MAXIMA OF 20-45MM. ELSEWHERE MAXIMA ARE EXPECTED BELOW
25MM. ON THURSDAY...THE EASTERLY WAVE MOVES INTO DRIER AIR IN THE
YUCATAN PENINSULA AND LOWER AMOUNTS OF PRECIPITATION ARE EXPECTED.
BELIZE...GUATEMALA...WEST-CENTRAL HONDURAS...AND EL SALVADOR ARE
FORECAST MAXIMA OF 20-35MM. EASTERN NICARAGUA AND NORTHERN COSTA
RICA ARE FORECAST SIMILAR AMOUNTS. PANAMA IS FORECAST MAXIMA OF
15-25MM.
IN NORTHERN SOUTH AMERICA...PERSISTENT TRADE WINDS FROM THE EAST
ARE EXPECTED TO FAVOR MOISTURE CONVERGENCE ALONG THE ANDES
MOUNTAINS FROM VENEZUELA TO NORTHERN ECUADOR/PERU. HOWEVER...DRIER
CONDITIONS ARE EXPECTED OVER VENEZUELA...THE GUIANAS...AND
NORTHERN BRASIL ON TUESDAY. AN EASTERLY WAVE OVER PANAMA IS
FAVORING MOISTURE CONVERGENCE OVER WESTERN COLOMBIA...WHERE
MODERATE AMOUNTS OF PRECIPITATION ARE EXPECTED. HOWEVER BY
THURSDAY...TROPICAL WAVES WILL MOVE INTO THE GUIANAS AND BRING
HIGHER AMOUNTS OF MOISTURE AND FAVOR MODERATE PRECIPITATION. ON
TUESDAY...EXPECT MAXIMA OF 40-80MM IN WESTERN COLOMBIA...AND
MAXIMA OF 20-45MM IN NORTH COLOMBIA AND NORTHWEST VENEZUELA.
ELSEWHERE OVER THE REGION...ISOLATED MAXIMA OF 15-25MM ARE
EXPECTED. ON WEDNESDAY...MOISTURE CONVERGENCE WILL FAVOR MAXIMA OF
20-35MM IN COLOMBIA...SOUTH VENEZUELA...AND INTO NORTH PERU.
ELSEWHERE...EXPECT MAXIMA OF 15-25MM. ON THURSDAY...THE TROPICAL
WAVES WILL FAVOR MAXIMA OF 20-45MM IN EAST-CENTRAL VENEZUELA AND
WEST GUYANA...WHILE NORTHERN VENEZUELA AND THE REST OF THE GUIANAS
CAN EXPECT MAXIMA OF 20-35MM. SIMILAR AMOUNTS ARE EXPECTED IN THE
LAKE MARACAIBO REGION IN VENEZUELA. WESTERN COLOMBIA AND ECUADOR
CAN EXPECT MAXIMA OF 15-25MM. THE AVAILABLE MOISTURE ASSOCIATED
WITH THE TROPICAL WAVES IS STILL UNCERTAIN...AS MODEL GUIDANCE IS
NOT IN AGREEMENT ON HOW MUCH MOISTURE WILL BE AVAILABLE ON
THURSDAY FOR AREAS OF THE GUIANAS...VENEZUELA...AND NORTHERN
BRASIL. THE FORECAST IS EXPECTED TO CHANGE AS GUIDANCE GAINS MORE
CONFIDENCE IN UPCOMING DAYS.
POSITIONS OF TROPICAL/EASTERLY WAVES INITIALIZED AT 12 UTC
TYPE SOF INIT 20/00 20/12 21/00 21/12 22/00 22/12 23/00 23/12
TW 12N 48W 50W 52W 53W 54W 56W 58W 60W 62W
TW 19N 57W 59W 61W 63W 64W 65W 66W 67W 68W
EW 16N 79W 81W 83W 85W 87W 89W 92W 94W 96W
EW 19N 95W 97W 99W 103W 105W 108W 112W 115W EXITS
A TROPICAL WAVE IS INITIALIZED AT 48W AND TO THE SOUTH OF 12N. IT
IS EXPECTED TO REMAIN OVER THE OPEN WATERS OF THE ATLANTIC
OCEAN...MAKING IT TO LAND BY WEDNESDAY OVER FRENCH GUIANA AND
SURINAME...WHERE EXPECT MAXIMA OF 15MM. ON THURSDAY...EXPECT
MAXIMA OF 20-35MM FROM EAST GUYANA TO WEST FRENCH GUIANA.
A TROPICAL WAVE IS INITIALIZED AT 57W AND TO THE SOUTH OF 19N. AS
IT APPROACHES THE LESSER ANTILLES ON TUESDAY...EXPECT MAXIMA OF
15MM. ON WEDNESDAY...THE WAVE WILL FAVOR MAXIMA OF 20-45MM IN THE
LESSER ANTILLES...AND MAXIMA OF 15-25MM IN NORTHEAST VENEZUELA AND
NORTH GUYANA. ON THURSDAY...THE WAVE WILL FAVOR MAXIMA OF 20-45MM
IN VENEZUELA AND WEST GUYANA...20-35MM IN THE LESSER
ANTILLES...AND 15-25MM FROM PUERTO RICO AND INTO THE VIRGIN
ISLANDS. LOCALIZED HIGHER AMOUNTS ARE POSSIBLE.
AN EASTERLY WAVE IS INITIALIZED AT 79W AND TO THE SOUTH OF 16N. ON
TUESDAY...THE WAVE WILL FAVOR MAXIMA OF 40-80MM IN WESTERN
COLOMBIA...30-60MM IN SOUTHERN COSTA RICA...20-45MM FROM PANAMA
INTO NORTHERN COLOMBIA...AND MAXIMA OF 20-35MM IN NORTHERN COSTA
RICA AND EASTERN NICARAGUA. ON WEDNESDAY...THE WAVE WILL FAVOR
MAXIMA OF 35-70MM IN NICARAGUA AND WESTERN EL SALVADOR...20-45MM
IN COSTA RICA...AND MAXIMA OF 15-25MM IN EAST EL SALVADOR AND
HONDURAS. ON THURSDAY...THE WAVE PROPAGATES WEST...WHERE IT WILL
FAVOR MAXIMA OF 20-35MM IN BELIZE...GUATEMALA..WEST HONDURAS...AND
EL SALVADOR. MAXIMA OF 15-25MM IS EXPECTED IN THE YUCATAN
PENINSULA INTO CHIAPAS AND TABASCO.
AN EASTERLY WAVE IS INITIALIZED AT 95W AND TO THE SOUTH OF 19N. ON
TUESDAY...THE WAVE WILL FAVOR MAXIMA OF 15-25MM IN OAXACA AND
GUERRERO. ON WEDNESDAY...THE WAVE WILL FAVOR MAXIMA OF 15-25MM
FROM NAYARIT TO GUERRERO ALONG THE SIERRA MADRE DEL SUR. ON
THURSDAY...THE WAVE WILL HAVE MINIMAL EFFECTS TO LAND AS IT
PROPAGATES WEST OVER THE OPEN OCEAN WATERS OF THE EAST PACIFIC
OCEAN.
ACOSTA...WPC (USA)
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