595
FXSA20 KWBC 191904
PMDSA
SOUTH AMERICA FORECAST DISCUSSION - INTERNATIONAL DESKS
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
203 PM EST THU DEC 19 2024
GFS DATA AT FTPPRD.NCEP.NOAA.GOV/PUB/DATA/NCCF/COM/GFS/PROD/
SOUTH AMERICAN FORECAST BULLETIN FOR 19 DEC 2024 AT 1900 UTC:
IN THE NORTHERN PORTION OF THE FORECAST AREA...A POTENT BOLIVIAN
HIGH EXTENDS OVER THE MAJORITY OF THE REGION...INTO
PARAGUAY...NORTH URUGUAY...AS WELL AS INTO EAST BRASIL AND CENTRAL
PORTIONS OF PERU ON THURSDAY. A SHORT WAVE UPPER LEVEL TROUGH IS
EXPECTED OVER PARAGUAY AND SOUTH BRASIL BY THURSDAY EVENING...AND
WILL PROPAGATE EAST INTO THE EARLY MORNING HOURS ON FRIDAY. IN THE
LOWER LEVELS...THE PRESENCE OF A FRONTAL BOUNDARY OVER CENTRAL
BOLIVIA...EAST PARAGUAY...AND SOUTH BRASIL IS FAVORING DEEP
CONVECTION AS TROPICAL MOISTURE IS BEING ADVECTED FROM THE NORTH
INTO THE AFOREMENTIONED REGIONS. ON FRIDAY THE SHORT WAVE TROUGH
IS EXPECTED TO ENTER SOUTH BRASIL AND INTO THE ATLANTIC
OCEAN...HOWEVER A WEAK UPPER JET FOLLOWS BEHIND OVER SOUTH
PARAGUAY AND SOUTH BRASIL WHICH WILL ENHANCE THE DIFFLUENCE IN THE
REGION WHILE IT INTERACTS WITH THE PERIPHERY OF THE BOLIVIAN HIGH.
THE REMNANTS OF THE FRONTAL BOUNDARIES REMAIN IN SOUTH BRASIL
WHICH WILL HELP TRIGGER HEAVY PRECIPITATION ON FRIDAY INTO
SATURDAY. THE EFFECTS OF THE UPPER LEVEL TROUGH ARE EXPECTED TO
DECREASE AS THE BOLIVIAN HIGH REMAINS IN THE REGION. YET THE
POTENTIAL FOR PRECIPITATION CONTINUES FROM SOUTH BOLIVIA INTO
SOUTH-CENTRAL BRASIL. A NEW FRONTAL BOUNDARY ENTERS INTO RIO
GRANDE DO SUL WHERE MODERATE PRECIPITATION IS EXPECTED. IN TERMS
OF PRECIPITATION...ON THURSDAY...EXPECT MAXIMA OF 50-100MM IN
EXTREME SOUTH PARAGUAY INTO WEST PARANA WITH A MODERATE RISK OF
SEVERE WEATHER. WHILE FROM SOUTH PARAGUAY INTO
MISIONES/CORRIENTES-ARGENTINA...AND RIO GRANDE DO SUL/SOUTH SANTA
CATARINA...EXPECT MAXIMA OF 40-80MM. SOUTH-CENTRAL BOLIVIA CAN
EXPECT MAXIMA OF 30-60MM WITH A SLIGHT RISK OF SEVERE WEATHER. ON
FRIDAY...PARANA AND WEST SAO PAULO CAN EXPECT MAXIMA OF
35-70MM...WHILE GOIAS AND MINAS GERAIS CAN EXPECT MAXIMA OF
25-50MM. OTHER REGIONS IN BRASIL AND BOLIVIA CAN EXPECT
GENERALIZED MAXIMA OF 20-45MM. A FRONTAL BOUNDARY ENTERING URUGUAY
AND NORTH BRASIL WILL FAVOR SIMILAR MAXIMA WITH A MARGINAL RISK OF
SEVERE WEATHER. ON SATURDAY...FROM SOUTH BOLIVIA/NORTH
PARAGUAY...INTO SOUTH CENTRAL BRASIL CAN EXPECT MAXIMA OF 30-60MM.
CENTRAL PORTIONS OF BRASIL...PERU...AND BOLIVIA CAN EXPECT
GENERALIZED MAXIMA OF 20-45MM. THE FRONTAL BOUNDARY OVER ARGENTINA
INTO SOUTH BRASIL WILL FAVOR MAXIMA OF 20-45MM.
IN THE SOUTHERN CONE OF SOUTH AMERICA...FRONTAL BOUNDARIES ARE
EXPECTED TO CONTINUOUSLY ENTER THE REGION FROM THURSDAY INTO
SATURDAY. AN UPPER TROUGH EXTENDS OVER MOST OF SOUTH CHILE AND
ARGENTINA...WITH SHORT WAVE TROUGHS EMBEDDED. ON OF THESE SHORT
WAVE TROUGHS IS EXPECTED OVER LOS LAGOS-CHILE AND CONTINUES INTO
CENTRAL ARGENTINA BY THURSDAY EVENING. THE UPPER JET ASSOCIATED IS
EXPECTED TO PROVIDE VENTILATION FOR PRECIPITATION...YET THE AMOUNT
OF AVAILABLE MOISTURE IS NOT AVAILABLE FOR HEAVIER AMOUNTS. LOS
LAGOS AND NORTH AYSEN CAN EXPECT MAXIMA OF 20-35MM. BY FRIDAY AND
SATURDAY THE PERIPHERY OF A RIDGE IS EXPECTED TO ENTER SOUTH
CHILE...AND A DECREASE IN AVAILABLE MOISTURE WILL CONTINUE INTO
THE WEEKEND. PRECIPITATION VALUES ARE EXPECTED TO DECREASE. SOUTH
AYSEN AND NORTH MAGALLANES CAN EXPECT MAXIMA OF 15-25MM ON
FRIDAY...WHILE MAGALLANES CAN EXPECT MAXIMA BELOW 15MM ON
SATURDAY.
CASTELLANOS...(WPC)
CLICK HERE TO GO TO PREVIOUS BULLETINS.
Main Text Page