432
FXSA20 KWBC 231922
PMDSA
SOUTH AMERICA FORECAST DISCUSSION - INTERNATIONAL DESKS
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
321 PM EDT WED OCT 23 2024
GFS DATA AT FTPPRD.NCEP.NOAA.GOV/PUB/DATA/NCCF/COM/GFS/PROD/
SOUTH AMERICAN FORECAST BULLETIN FOR 23 OCT 2024 AT 1930 UTC:
ON WEDNESDAY...IN THE SOUTHERN CONE OF SOUTH AMERICA...AN UPPER
LEVEL SEGREGATED LOW IS ENTERING THE CONTINENT AND IT IS EXPECTED
TO BE A SHORTWAVE TROUGH OVER ARGENTINA BY THURSDAY MORNING. WHILE
THE TROUGH IS MOVING EASTWARD A JET COUPLING BETWEEN THE
SUBTROPICAL JET AND THE NORTH POLAR JET IS EXPECTED OVER CENTRAL
ARGENTINA...ENHANCING THE DEEP CONVECTION OVER THE REGION ON
WEDNESDAY INTO THURSDAY. THE UPPER DIVERGENCE IS EXPECTED TO
EXTEND INTO URUGUAY AND SOUTH BRASIL....FROM WEDNESDAY NIGHT INTO
THURSDAY MORNING. IN THE LOWER LEVELS...A FRONTAL BOUNDARY BEGINS
TO PROPAGATE FROM NORTH ARGENTINA INTO URUGUAY BY WEDNESDAY
EVENING. WITH THE AMOUNTS OF AVAILABLE MOISTURE IN THE
REGION...THE REGION OF BUENOS AIRES CAN EXPECT MAXIMA OF 40-80MM
WITH AN ELEVATED RISK OF SEVERE WEATHER. ALONG THE FRONTAL
BOUNDARY IN URUGUAY TO ENTRE RIOS AND SOUTH CORRIENTES-ARGENTINA
EXPECT MAXIMA OF 30-60MM WITH A MODERATE RISK OF SEVERE WEATHER.
INTO THURSDAY...THE UPPER LEVEL SHORTWAVE TROUGH BECOMES
NEGATIVELY TILTED BY THE AFTERNOON HOURS OVER SOUTH BRASIL AND
URUGUAY...WHERE SEVERE WEATHER IS EXPECTED WITH HEAVY
PRECIPITATION. IN THE LOWER LEVELS...THE PRESENCE OF THE FRONTAL
BOUNDARY WILL TRIGGER THUNDERSTORMS FROM SANTA CATARINA-BRASIL
INTO SOUTH MATO GROSSO DO SUL...AND EXTEND INTO PORTIONS OF
CENTRAL BOLIVIA. THE PRESENCE OF AVAILABLE MOISTURE TRANSPORT DUE
TO THE LOW LEVEL JETS WILL ENHANCE THE POSSIBILITY OF HEAVY
PRECIPITATION. FROM SANTA CATARINA...TO WEST RIO DE JANEIRO EXPECT
MAXIMA OF 30-60MM WITH A MARGINAL RISK OF SEVERE WEATHER.
EXTENDING ALONG THE WESTERN BRASIL BORDER WITH PARAGUAY EXPECT
MAXIMA OF 20-35MM. INTO THE EASTERN PORTIONS OF BOLIVIA...MAXIMA
OF 25-50MM ARE EXPECTED. ISOLATED HEAVIER AMOUNTS OF PRECIPITATION
COULD BE EXPECTED IN THE REGION. BY FRIDAY...THE SHORT WAVE TROUGH
HAS MOVED OVER THE ATLANTIC OCEAN AND AWAY FROM THE FORECAST
REGION. THE PRESENCE OF THE WIDE UPPER TROUGH EXTENDS OVER MOST OF
THE SOUTHERN CONE OF SOUTH AMERICA INTO NORTH
ARGENTINA...URUGUAY...AND SOUTH BRASIL. IN THE LOWER LEVELS...THE
PRESENCE OF THE WEAKENING FRONTAL BOUNDARY REMAINS...WHILE THE
AVAILABLE MOISTURE IS PRESENT DURING THE FORECAST PERIOD. THESE
WILL TRIGGER TO CONTINUATION OF DEEP CONVECTION OVER THE REGION
AND ISOLATED HEAVIER AMOUNTS COULD BE PRESENT. FROM EAST SAO PAULO
INTO RIO DE JANEIRO...EXPECT MAXIMA OF 25-50MM. WHILE THE REGION
WITH THE REMNANTS OF THE FRONTAL BOUNDARY CAN EXPECT MAXIMA OF
20-35MM...WHILE ISOLATED HIGHER AMOUNTS ARE POSSIBLE. IN THE
WESTERN SIDE OF THE FRONT...INTO NORTH BOLIVIA...MAXIMA OF 25-50MM
ARE EXPECTED.
IN PORTIONS OF PERU AND INTO WEST AND CENTRAL BRASIL ON
WEDNESDAY...THE MOIST PLUME THAT IS ENTERING THE REGION WILL BE
ENHANCED BY THE UPPER TROUGH IN EAST PERU THAT WILL FAVOR DEEP
CONVECTION ALONG THE EAST OF THE ANDES AND TOWARDS THE AMAZON
REGIONS IN BRASIL AND PERU. THIS WILL EXTEND INTO NORTHERN
PORTIONS OF BOLIVIA BY THURSDAY AS THE MOISTURE IS BEING ADVECTED
SOUTH FROM THE TROPICAL REGION OF NORTH SOUTH AMERICA...FAVORING
MOISTURE CONVERGENCE AND HEAVY PRECIPITATION. ON FRIDAY...THE
PASSING OF THE FRONTAL BOUNDARY INTO SOUTH AND CENTRAL
BOLIVIA...WILL FAVOR INCREASED PRECIPITATION IN THE COUNTRY BY
FRIDAY. AHEAD OF THE FRONT...HIGHER LEVELS OF MOISTURE
CONTINUE...WHILE THE PRESENCE OF MOISTURE CONVERGENCE IN THE LOW
LEVELS FEATURES THE POTENTIAL FOR A REGION OF CONVERGENCE SIMILAR
TO THE SOUTH ATLANTIC CONVERGENCE ZONE (SACZ). THE CONFIDENCE THAT
THE POTENTIAL FOR A POTENTIAL SACZ EVENT IS INCREASING...AND THE
FORECAST IS EXPECTED TO CHANGE AS MORE CONFIDENCE GROWS. IN TERMS
OF PRECIPITATION...ON WEDNESDAY...MAXIMA OF 25-50MM WITH HIGHER
AMOUNTS OF PRECIPITATION COULD BE EXPECTED IN SOUTH
AMAZONAS-BRASIL INTO SECTIONS OF GOIAS. CENTRAL PORTIONS OF PERU
CAN EXPECT MAXIMA OF 20-40MM. ON THURSDAY...CENTRAL PERU CAN
EXPECT MAXIMA OF 25-50MM. ELSEWHERE IN THE REGION...EXPECT
GENERALIZED MAXIMA OF 20-35MM WITH HIGHER AMOUNTS POSSIBLE. BY
FRIDAY...A SLIGHT DECREASE IS EXPECTED IN PERU INTO
AMAZONAS-BRASIL WITH MAXIMA OF 20-35MM.
IN SOUTHERN CHILE...AN UPPER TROUGH IS EXPECTED OVER THE REGION BY
THURSDAY MORNING...WHERE THE ASSOCIATED JET TO THE NORTH IS
EXPECTED TO BE ZONAL. A FRONTAL BOUNDARY IN THE LOWER LEVELS AND
AT ATMOSPHERIC RIVER ENTERS FROM WEDNESDAY EVENING INTO
THURSDAY...ENHANCING THE CHANCE OF PRECIPITATION. ON
THURSDAY...INTO FRIDAY...ANOTHER ATMOSPHERIC RIVER IS EXPECTED TO
ENTER THROUGH MAGALLANES...WITH A HIGHER AMOUNT OF AVAILABLE
MOISTURE. THIS SYSTEM WILL CONTINUE TO PUSH NORTHWARD INTO THE
ZONA AUSTRAL BY FRIDAY...BRINGING WITH IT INCREASED MOISTURE INTO
THE REGION. ON WEDNESDAY AND THURSDAY EXPECT GENERALIZED MAXIMA OF
15-25MM IN MAGALLANES. ON FRIDAY...AN INCREASE IS EXPECTED WITH
MAXIMA OF 20-35MM FROM SOUTH AYSEN INTO MAGALLANES.
CASTELLANOS...(WPC)
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