636
FXSA20 KWBC 271951
PMDSA
SOUTH AMERICA FORECAST DISCUSSION - INTERNATIONAL DESKS
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
250 PM EST MON JAN 27 2025
GFS DATA AT FTPPRD.NCEP.NOAA.GOV/PUB/DATA/NCCF/COM/GFS/PROD/
SOUTH AMERICAN FORECAST BULLETIN FOR 27 JAN 2025 AT 1930 UTC:
THE SOUTH AMERICAN CONTINENT IS SEEING THE EFFECTS OF A CONVERGENT
PHASE OF THE MADDEN-JULIAN OSCILLATION ON MONDAY AND INTO TUESDAY.
AS THE WORK WEEK PROGRESSES THE CSF MODEL IS SUGGESTING A
POTENTIAL ATMOSPHERIC KELVIN WAVE ENTERING THE REGION BY
MIDWEEK...POTENTIALLY ASSISTING IN ENHANCED CONVECTION. ALTHOUGH
THE POTENTIAL FOR DEEP CONVECTION COULD EXIST WITH THE PRESENCE OF
A KELVIN WAVE...SYNOPTIC CONDITIONS WILL CONTINUE TO BE THE
DRIVERS FOR ANY HEAVY PRECIPITATION OVER THE CONTINENT.
ON MONDAY...A PROMINENT UPPER LEVEL TROUGH EXTENDS INTO PORTIONS
OF CENTRAL ARGENTINA AND CHILE...WHICH THE BASE IS EXPECTED TO
INTERACT WITH THE BOLIVIAN HIGH CENTERED JUST WEST OF NORTH CHILE
AND SOUTH PERU...AND EXTENDS FROM NORTH CHILE EASTWARD THROUGH
SOUTH BRASIL. AN UPPER LEVEL TROUGH WITH A REDUCED AMPLITUDE IS
EXPECTED TO MOVE SLOWER OVER NORTH-CENTRAL CHILE INTO THE CUYO
REGION OF ARGENTINA. AHEAD OF THIS TROUGH...A SHORTWAVE TROUGH IS
EXPECTED TO REACH THE AFOREMENTIONED REGION AND PROVIDE LIFT FROM
THE CUYO REGION TO CENTRAL ARGENTINA BY TUESDAY
MORNING...ELEVATING THE POTENTIAL FOR SEVERE WEATHER ON THE EARLY
HOURS ON TUESDAY. FURTHER ON TUESDAY...THE UPPER LEVEL TROUGH IS
EXPECTED TO MAKE IT TO WEST AND CENTRAL ARGENTINA FAVORING DEEP
CONVECTION AND SEVERE WEATHER...AS WELL AS HEAVY
PRECIPITATION...FROM CENTRAL ARGENTINA INTO THE CHACO REGION. THIS
SYSTEM WILL HAVE FAVORABLE AMOUNT OF AVAILABLE MOISTURE WITH THE
SALLJ TRANSPORTING MOISTURE INTO THE REGION WITH PRECIPITABLE
VALUES EXCEEDING 50MM AS WELL AS ENHANCING THE MOISTURE
CONVERGENCE AGAINST THE ANDEAN MOUNTAIN RANGE. AS THIS TROUGH
CONTINUES PROPAGATING EASTWARD INTO WEDNESDAY...THE AREA OF
DIVERGENCE EXTENDS EASTWARD OVER SOUTH PARAGUAY...SOUTH
BRASIL...AND URUGUAY. IN TERMS OF PRECIPITATION...ON
MONDAY...NORTH CENTRAL ARGENTINA CAN EXPECT MAXIMA OF 25-50MM WITH
A MODERATE RISK OF SEVERE WEATHER. ON TUESDAY...THE CHACO REGION
OF ARGENTINA CAN EXPECT MAXIMA OF 30-60MM...WHILE ALONG THE
CORDILLERA...EXPECT MAXIMA OF 40-80MM. A RISK OF MCS FORMATION IS
EXPECTED. ON WEDNESDAY...EXPECT MAXIMA OF 30-60MM IN NORTHEAST
ARGENTINA...WITH A RISK OF MCS FORMATION. PARAGUAY CAN EXPECT
MAXIMA OF 20-40MM.
IN THE SOUTHERN CONE OF THE CONTINENT...SOUTH CHILE IS EXPECTED TO
SEE MODERATE PRECIPITATION IN THE AUSTRAL REGION OF CHILE OVER THE
NEXT THREE DAYS. THAT IS DUE TO THE CONTINUOUS PRESENCE OF THE
POLAR JET OVER THE REGION...PROVIDING VENTILATION IN THE LOWER
LEVELS AS A SERIES OF FRONTAL BOUNDARIES WITH AN ASSOCIATED
ATMOSPHERIC RIVER WILL FAVOR MOISTURE CONVERGENCE ALONG THE
MOUNTAIN REGION IN AUSTRAL CHILE...PRIMARILY ON TUESDAY AND
WEDNESDAY. ON MONDAY...EXPECT A FRONTAL BOUNDARY TO ENTER
MAGALLANES-CHILE BY LATE MONDAY EVENING WITH A POTENTIAL FOR
MAXIMA OF 20-35MM IN MAGALLANES. AYSEN AND SOUTH MAGALLANES CAN
EXPECT MAXIMA BELOW 25MM. ON TUESDAY...THE ATMOSPHERIC RIVER
ENTERS THE AUSTRAL REGION WITH CONTINUOUS MOISTURE TRANSPORT.
SOUTH AYSEN AND NORTH MAGALLANES CAN EXPECT MAXIMA OF
25-50MM...WITH A POTENTIAL FOR LOCALLY HIGHER AMOUNTS. SOUTH
MAGALLANES CAN EXPECT MAXIMA OF 15MM. ON WEDNESDAY...MOISTURE
CONTINUES TO ENTER THE REGION AND WILL FAVOR MOISTURE CONVERGENCE
IN MAGALLANES-CHILE. A POTENTIAL FOR MAXIMA OF 50-100MM ARE
EXPECTED FOR THE REGION. THE UPPER LEVEL JET WILL FAVOR
VENTILATION FOR THE HEAVY PRECIPITATION OVER SOUTH CHILE.
IN THE NORTHERN REGION OF THE CONTINENT...THE BOLIVIAN HIGH
EXTENDS OVER PERU...BOLIVIA...AND WEST BRASIL. THE VENTILATION AT
THE PERIPHERY OF THE UPPER LEVEL HIGH PRESSURE SYSTEM WILL
INTERACT WITH THE UPPER TROUGH OVER NORTHERN BRASIL. THIS REGION
WILL CONTINUE TO SEE SHOWERS AS LOWER LEVEL TROUGHS TRIGGER MAXIMA
OF 15-25MM ON MONDAY OVER NORTH BRASIL. THE CENTRAL REGIONS OF
PERU CAN EXPECT MAXIMA OF 20-35MM ON MONDAY. ON TUESDAY...THE
AFOREMENTIONED REGIONS CAN EXPECT MAXIMA OF 20-35MM. BY
WEDNESDAY...EXPECT MAXIMA OF 20-40MM IN NORTH AND CENTRAL BRASIL.
CASTELLANOS...(WPC)
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