SOUTH AMERICA FORECAST DISCUSSION - INTERNATIONAL DESKS
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
338 PM EDT MON SEP 09 2024

GFS DATA AT FTPPRD.NCEP.NOAA.GOV/PUB/DATA/NCCF/COM/GFS/PROD/

SOUTH AMERICAN FORECAST BULLETIN FOR 09 SEP 2024 AT 1945 UTC:

ON MONDAY...A STRONG RIDGING PATTERN IS EXPECTED OVER THE NORTHERN
PORTION OF THE REGION...WHILE A UPPER LEVEL TROUGH EXTENDS INTO
PORTIONS OF SOUTHERN PORTIONS OF BOLIVIA. A WEAKER UPPER TROUGH
EXTENDS TO THE WEST OF PERU AND IT IS EXPECTED TO PROCEED INLAND
BY MONDAY EVENING. TO THE SOUTH...ANOTHER TROUGH IS EXPECTED TO
EXTEND FROM THE CENTRAL PORTIONS TO CHILE...AND INTO SOUTHEASTERN
ARGENTINA. THE ASSOCIATED UPPER JET ENTERS CENTRAL CHILE IN A
ZONAL POSITION...AND COULD BRING FAVORABLE UPPER LEVEL CONDITIONS
FOR PRECIPITATION IN CENTRAL CHILE INTO THE ZONA SUR...WITH THE
ENTRANCE OF TWO FRONTAL BOUNDARIES INTO THE REGION BY MONDAY
EVENING. MAXIMA OF 20-35MM ARE EXPECTED FROM CENTRAL CHILE TO LOS
RIOS. TO THE EAST...ANOTHER FRONTAL BOUNDARY EXTENDS FROM NORTH
ARGENTINA...THROUGH URUGUAY AND INTO THE SOUTH ATLANTIC OCEAN.
WITH THE PRESENCE OF THE UPPER TROUGH...MAXIMA OF 15-30MM ARE
EXPECTED IN EAST URUGUAY AND EXTREME SOUTHEAST RIO GRANDE DO SUL.

ON TUESDAY...THE UPPER LEVEL TROUGH PROPAGATES TO THE
NORTHEAST...EXTENDING INTO CENTRAL ARGENTINA AND BUENOS AIRES. AN
INTENSIFICATION OF THE UPPER IS EXPECTED AS TWO JETS MAY BE
EXPECTED TO COUPLE OVER EASTERN ARGENTINA BY TUESDAY EVENING. THE
ENHANCE UPPER DIVERGENT CONDITIONS ARE EXPECTED TO EXTEND FROM
EAST ARGENTINA INTO URUGUAY...AND IN ADDITION...THE PRESENCE OF
SHORTWAVE TROUGHS IN THE MID LEVELS WILL FAVOR ELEVATED RISK OF
SEVERE WEATHER INTO SOUTH URUGUAY. THE TRIGGER IS THE FRONTAL
BOUNDARIES THAT ARE EXPECTED IN THE SAME REGION...WHERE THE COLD
FRONT ADVANCING NORTH INTO CENTRAL AND EAST ARGENTINA WILL LIKELY
PUSH AGAINST THE WEAKENING STATIONARY FRONT OVER CENTRAL URUGUAY
AND NORTH ARGENTINA BY EARLY WEDNESDAY MORNING. MAXIMA OF 20-40MM
ARE EXPECTED IN URUGUAY. EAST ARGENTINA CAN EXPECT MAXIMA OF
15-25MM.

ON WEDNESDAY...THE FRONTAL BOUNDARY CONTINUES TO PROPAGATE NORTH
AND EXTENDS FROM CENTRAL BOLIVIA...TO NORTH RIO GRANDE DO SUL BY
WEDNESDAY EVENING. THE POTENTIAL FOR SEVERE WEATHER HAS DECREASED
WITH THE WEAKENING OF THE UPPER JETS OVER URUGUAY AND SOUTH
BRASIL. FROM CORRIENTES-ARGENTINA TO RIO GRANDE DO SUL EXPECT A
SLIGHT RISK OF SEVERE WEATHER WITH MAXIMA OF 20-35MM. MAXIMA OF
15-25MM ARE EXPECTED IN URUGUAY AND ENTRE RIOS-ARGENTINA. IN
SOUTHERN CHILE...EXPECT A SHORTWAVE TROUGH IN THE MID TO UPPER
LEVELS TO FAVOR UPPER DIVERGENT CONDITIONS FOR PRECIPITATION IN
THE ZONA AUSTRAL AND ZONA SUR OF CHILE. AN INCREASE IN
PRECIPITABLE WATER DUE TO A WEAK INCOMING ATMOSPHERIC RIVER MAY
FAVOR MAXIMA OF 20-35MM IN SOUTH AYSEN AND NORTH MAGALLANES...AND
MAXIMA OF 15-25MM IN SOUTH MAGALLANES...WITH A CHANCE OF
RAIN/SNOW.

ACOSTA...(WPC)