627
FXSA20 KWBC 171913
PMDSA
SOUTH AMERICA FORECAST DISCUSSION - INTERNATIONAL DESKS
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
313 PM EDT THU OCT 17 2024
GFS DATA AT FTPPRD.NCEP.NOAA.GOV/PUB/DATA/NCCF/COM/GFS/PROD/
SOUTH AMERICAN FORECAST BULLETIN FOR 17 OCT 2024 AT 1915 UTC:
OVER THE SOUTH AMERICAN CONTINENT...THE PERSISTENT UPPER LEVEL
PROPAGATION OF TROUGHS AND SHORT WAVE TROUGHS INTO THE CENTRAL AND
SOUTHERN PORTION OF THE CONTINENT ARE PROVIDING THEÂDYNAMIC
PATTERNS FOR FAVORABLE HEAVY PRECIPITATION AND SEVERE WEATHER
CONDITIONS. ON THURSDAY...A DOMINATING UPPER RIDGE IS PRESENT IN
THE PACIFIC OCEAN...TO THE WEST OF PERU AND ECUADOR. THIS BLOCKING
PATTERN IN THE NORTH IS PUSHING THE EASTWARD PROPAGATING TROUGHS
TO REMAIN IN THE SOUTH OVER CHILE...PARAGUAY...ARGENTINA...AND
URUGUAY. A WIDE TROUGH PATTERN IS PRESENT OVER CHILE...WITH
MULTIPLE SHORT WAVE TROUGHS EMBEDDED IN THE TROUGH...PROPAGATING
INTO THE CONTINENT. OVER NORTHERN ARGENTINA...A POTENT SHORT WAVE
TROUGH IN THE MID TO UPPER LEVEL IS EXPECTED TO FAVOR SEVERE
WEATHER AND HEAVY PRECIPITATION. ISOLATED MAXIMA OF 40-80MM WITH A
MODERATE RISK OF SEVERE WEATHER AND MCS FORMATION IS EXPECTED IN
FORMOSA...CHACO-ARGENTINA...AND SANTA FE. FROM
SALTA...TUCUMAN...AND NORTH SANTIAGO DEL ESTERO CAN EXPECT MAXIMA
OF 20-45MM WITH A SLIGHT RISK OF SEVERE WEATHER. SOUTHERN PARAGUAY
CAN EXPECT MAXIMA OF 20-35MM WITH A SLIGHT RISK OF SEVERE WEATHER.
THE FRONTAL SYSTEM ASSOCIATED WITH THIS PRECIPITATION IS EXPECTED
TO QUICKLY PUSH NORTHWARD AS THE MID TO UPPER LEVEL TROUGH
ENHANCES ITS MOVEMENT.
ON FRIDAY...ANOTHER SHORT WAVE TROUGH ENTERS INTO NORTHERN
CHILE...SOUTH PERU...BOLIVIA...PARAGUAY...AND NORTH
ARGENTINA...AMPLIFIED BY THE UPPER JET TO THE WEST OF THE TROUGH.
FAVORABLE UPPER CONDITIONS WILL PUSH THE FRONTAL SYSTEM FURTHER
NORTH...ALTHOUGH THE FRONT IS EXPECTED TO WEAKEN AS IT ADVANCES
INTO CENTRAL AND EAST BRASIL. EXPECT SEVERE WEATHER OVER WEST MATA
GROSSO DO SUL AND HEAVY PRECIPITATION AS THE FRONTAL BOUNDARY
ENCOUNTERS THE MOIST TROPICAL MOISTURE IN BRASIL AND PORTIONS OF
BOLIVIA.ÂMAXIMA OF 25-50MM ARE EXPECTED IN EAST BOLIVIA...AND
MATA GROSSO DO SUL. THE WEAKENING FRONT WILL FAVOR MAXIMA OF
20-4OMM FROM NORTHERN BOLIVIA INTO PORTIONS OF CENTRAL AND
SOUTHERN BRASIL. INTO THE REGIONS OF RIO DE JANEIRO AND ESPIRITO
SANTO EXPECT MAXIMA OF 15-25MM.
BY SATURDAY...THE MID TO UPPER TROUGH IS EXPECTED OVER
SOUTH-CENTRAL BRASIL WHERE IT BEGINS TO SUGGEST A POTENTIAL
SEGREGATION IN THE MID LEVELS OVER EAST PARAGUAY AND MATA GROSSO
DO SUL-BRASIL. THIS WILL FAVOR THE LOWERING OF PRESSURES IN THE
LOWER LEVELS OF THE ATMOSPHERE...ACTIVATING THE REMNANTS OF THE
FRONTAL SYSTEM FROM SOUTH BRASIL...ALONG BOLIVIA...AND INTO
SOUTHERN PERU TO FAVOR PRECIPITATIONS SIMILAR TO THE SOUTH
ATLANTIC CONVERGENCEÂZONE (SACZ). HOWEVER...THIS FEATURE IS NOT
EXPECTED TO LAST AND WILL WEAKEN BY SUNDAY...AS THE WINDS BEGIN TO
SHIFT TO THE SOUTH AND RE-ENTERING SOUTHERN BOLIVIA...PARAGUAY AND
NORTH ARGENTINA. THE REMNANTS OF THE FRONT...ENHANCED BY THE UPPER
DIVERGENT CONDITIONS WILL FAVOR MAXIMA OF 30-60MM IN GOIAS AND
WEST MINAS GERAIS-BRASIL. IN SOUTH MINAS GERAIS AND PORTIONS OF
SAO PAULO...EXPECT MAXIMA OF 20-45MM WITH A SLIGHT RISK OF SEVERE
WEATHER. THE FRONTAL BOUNDARY OVER RIO DE JANEIRO AND ESPIRITO
SANTO WILL FAVOR MAXIMA OF 50-100MM WITH A SLIGHT RISK OF SEVERE
WEATHER. THE REST OF THE NORTHERN REGION OF BRASIL...INTO
PERU...AND NORTH BOLIVIA CAN EXPECT MAXIMA OF 20-35MM WITH
ISOLATED HIGHER AMOUNTS EXPECTED.
CASTELLANOS...(WPC)
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