713
FXSA20 KWBC 242006
PMDSA
SOUTH AMERICA FORECAST DISCUSSION - INTERNATIONAL DESKS
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
306 PM EST FRI JAN 24 2025
GFS DATA AT FTPPRD.NCEP.NOAA.GOV/PUB/DATA/NCCF/COM/GFS/PROD/
SOUTH AMERICAN FORECAST BULLETIN FOR 24 JAN 2025 AT 1930 UTC:
THE UPPER LEVEL RIDGE OVER THE CENTRAL PORTION OF THE CONTINENT
EXTENDS OVER PERU...BOLIVIA...PARAGUAY...NORTH ARGENTINA...AND
SOUTH BRASIL BY FRIDAY EVENING. THIS WILL BE INTERACTING WITH A
SHORTWAVE UPPER LEVEL TROUGH OVER NORTH BRASIL ON FRIDAY INTO
SATURDAY...PROVIDING VENTILATION OVER AMAZONAS-BRASIL AND INTO
VENEZUELA/COLOMBIA. FURTHER EAST...ANOTHER TROUGH IN THE UPPER
LEVELS IS RETROGRADING JUST EAST OF NORTHEAST BRASIL ON FRIDAY.
THROUGHOUT THE WEEKEND...THIS UPPER LEVEL TROUGH WILL CONTINUE TO
RETROGRADE INTO EAST AND NORTH BRASIL AND THE GUIANAS...FAVORING A
DRYING TREND AND A DECREASE IN PRECIPITATION TOTALS INTO MONDAY
MORNING. ON FRIDAY...EXPECT MAXIMA OF 20-45MM FROM SOUTH
VENEZUELA/GUIANAS INTO NORTHEAST AMAZONAS-BRASIL...PARA...AND
MARANHAO. THE PRESENCE OF THE DOUBLE ITCZ ENTERING NORTH AMAPA AND
NORTH PARA WILL FAVOR MAXIMA OF 30-60MM. NORTHERN PERU AND SOUTH
COLOMBIA CAN EXPECT MAXIMA OF 20-35MM. WHILE MOISTURE CONTINUES TO
BE ADVECTED FROM THE TROPICAL REGIONS THROUGH PERU AND
BOLIVIA...EXPECT MOISTURE CONVERGENCE IN CENTRAL PERU WITH MAXIMA
OF 20-35MM. ON SATURDAY...THE DRYING TREND BECOMES MORE PROMINENT
AS EASTERN BRASIL IS EXPECTED TRACE AND ISOLATED AMOUNTS OF
PRECIPITATION. TO THE NORTHERN REGIONS OF THE CONTINENT...THE ITCZ
WILL INTERACT WITH THE PERIPHERY OF THE RETROGRADING UPPER
TROUGH...AS WELL AS THE SHORT WAVE TROUGH IN THE UPPER LEVELS...
IN AMAZONAS-BRASIL/SOUTH VENEZUELA AND COLOMBIA. FROM EAST AMAPA
TO NORTH PARA AS WELL AS SOUTH VENEZUELA INTO AMAZONAS-BRASIL
EXPECT MAXIMA OF 30-60MM. ELSEWHERE IN THE GUIANAS...RORAIMA...AND
NORTH PARA-BRASIL EXPECT MAXIMA OF 20-45MM. MAXIMA DECREASE OVER
WEST BRASIL AND CENTRAL PERU WITH MAXIMA BELOW 25MM. ON
SUNDAY...THE UPPER LEVEL TROUGH IS CENTERED OVER EASTERN BRASIL
AND EXTENDS INTO CENTRAL AMAZONAS...WHERE THE SURROUNDING REGIONS
WILL ALSO SEE A DECREASE IN AVAILABLE MOISTURE DUE TO THE
ADVECTION OF DRIER AIR IN THE TRADE WINDS OVER THE GUIANAS AND
NORTH BRASIL. THE MOISTURE WILL BE ADVECTED FURTHER WEST INTO
COLOMBIA...PERU...AND WEST AMAZONAS-BRASIL...WHERE EXPECT MAXIMA
OF 15-25MM.
IN CENTRAL SOUTH AMERICA...THE UPPER RIDGE IS INTERACTING WITH THE
PROGRESSIVE UPPER TROUGHS PROPAGATING EASTWARD OVER THE SOUTHERN
CONE OF THE CONTINENT. A SERIES OF SHORT WAVE TROUGHS ARE EXPECTED
TO PROPAGATE OVER PORTIONS OF NORTH-CENTRAL CHILE INTO NORTH
ARGENTINA...WHILE MAKING THEIR WAY INTO SOUTH BRASIL OVER THE
WEEKEND. THESE PULSES OF SHORTWAVES WILL FAVOR SEVERE WEATHER AND
THUNDERSTORMS IN THE REGION...AS TROUGHS DEVELOP IN THE LOWER
LEVELS ON FRIDAY...AND A FRONTAL BOUNDARY PROPAGATES OVER NORTHERN
ARGENTINA THROUGH URUGUAY AND INTO RIO GRANDE DO SUL BY SUNDAY
EVENING. ON SUNDAY...A NEW FRONTAL BOUNDARY HAS CROSSED OVER CHILE
AND INTO THE PATAGONIA REGION OF ARGENTINA...ENHANCED BY AN UPPER
LEVEL JET OVER THE REGION...THIS WILL FAVOR THE PRESENCE OF LLJ
FROM CENTRAL ARGENTINA TO AROUND 50S AND SOUTHWARD. THE ENTRANCE
OF THE ASSOCIATED ATMOSPHERIC RIVER INTO SOUTHERN CHILE WILL FAVOR
HEAVY PRECIPITATION IN THE AUSTRAL REGION OF CHILE. WHILE THE
CONTINUED ADVECTION OF TROPICAL MOISTURE THROUGH THE SALLJ INTO
CENTRAL ARGENTINA WILL FAVOR HEAVY PRECIPITATIONS THERE AS WELL
INTO THE WEEKEND. IN TERMS OF PRECIPITATION...EXPECT MAXIMA OF
30-60MM WITH A MARGINAL RISK OF SEVERE WEATHER FROM
CORRIENTES-ARGENTINA TO SOUTH PARAGUAY AND EXTREME NORTH RIO
GRANDE DO SUL. THE CHACO REGION OF ARGENTINA CAN FAVOR MAXIMA OF
25-50MM. URUGUAY...AND NORTH CENTRAL ARGENTINA CAN EXPECT MAXIMA
OF 20-35MM...URUGUAY EXPECTING A MODERATE RISK OF SEVERE WEATHER.
THE ZONA AUSTRAL OF CHILE CAN EXPECT MAXIMA OF 15MM. ON
SATURDAY...THE CHACO REGION CONTINUES TO SEE THE PRESENCE OF
MOISTURE FROM THE ADVECTION OF THE SALLJ...WHERE CONVERGENCE WILL
FAVOR MAXIMA OF 30-60MM. FROM SOUTH PARAGUAY...THROUGH SOUTH
BRASIL...EXPECT MAXIMA OF 20-35MM AS THE TROUGHS IN THE LOWER
LEVELS ARE ENHANCED BY THE INTERACTION OF THE ENTERING UPPER
TROUGH AND THE UPPER LEVEL RIDGE THAT EXTENDS INTO SOUTH BRASIL.
THE FRONTAL BOUNDARY REACHES THE CORDOBA REGION OF ARGENTINA WHERE
EXPECT GENERALIZED MAXIMA OF 15-30MM. SOUTH CHILE CAN EXPECT
MAXIMA OF 20-40MM AS A FRONTAL BOUNDARY ENTERS PROPAGATES INTO THE
REGION. ON SUNDAY...CENTRAL ARGENTINA CAN EXPECT MAXIMA OF 25-50MM
WITH A MODERATE RISK OF SEVERE WEATHER AS AN UPPER TROUGH BECOMES
SLIGHTLY NEGATIVELY AND THE BASE AND DIVERGENCE ENTERS THE
AFOREMENTIONED REGION. SOUTHERN CHILE CAN EXPECT MOISTURE TO
CONTINUE CONVERGING ALONG THE MOUNTAIN RANGE AND FAVOR MAXIMA OF
25-50MM. IN NORTHERN ARGENTINA...THE MOISTURE CONVERGENCE
ASSOCIATED WITH THE ADVECTED MOISTURE FROM THE SALLJ WILL FAVOR
MAXIMA OF 20-35MM FROM NORTH ARGENTINA INTO CENTRAL
PARAGUAY...WHILE FROM MATO GROSSO DO SUL THROUGH SAO PAULO/RIO DE
JANEIRO THEY CAN EXPECT MAXIMA OF 25-50MM...ENHANCED BY UPPER
LEVEL SHORTWAVE TROUGHS.
CASTELLANOS...(WPC)
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