606
FXSA20 KWBC 121906
PMDSA
SOUTH AMERICA FORECAST DISCUSSION - INTERNATIONAL DESKS
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
205 PM EST TUE NOV 12 2024
GFS DATA AT FTPPRD.NCEP.NOAA.GOV/PUB/DATA/NCCF/COM/GFS/PROD/
SOUTH AMERICAN FORECAST BULLETIN FOR 12 NOV 2024 AT 1900 UTC:
IN THE CENTRAL PORTIONS OF THE CONTINENT...A FRONTAL BOUNDARY IS
PROPAGATING NORTH AND EAST OVER INTO BOLIVIA...NORTH
PARAGUAY...AND SOUTH BRASIL...WHERE THE CONVERGENCE OF MOISTURE IN
THE LOWER LEVELS AHEAD OF THE FRONT ARE ACTIVATING DEEP CONVECTION
FROM PERU INTO NORTH BOLIVIA...AND ALONG THE MATO GROSSO DO SUL
AND PARANA. ASSISTED IN THE MID TO UPPER LEVELS BY THE DIVERGENCE
ALONG THE TROUGH THAT EXTENDS OVER MOST OF THE CENTRAL REGION OF
SOUTH AMERICA. HIGH AMOUNTS OF PRECIPITABLE WATER ARE PRESENT IN
MOST OF THE NORTH PORTION OF THE CONTINENT AND WILL CONTINUE TO
PERSIST OVER THE NEXT SEVERAL DAYS. ON TUESDAY...THE FRONTAL
BOUNDARY IS EXPECTED TO REACH THE BORDER BETWEEN
PERU/BOLIVIA...AND EXTEND ALONG NORTH BOLIVIA...AND ALONG THE
SOUTHERN SECTOR OF BRASIL...WHERE IT WILL REACH SOUTH SAO PAULO BY
THE EVENING HOURS. EXPECT THESE REGIONS TO RECEIVE HEAVY
PRECIPITATION OF 35-70MM IN SOUTH PERU...ACRE-BRASIL...AND NORTH
BOLIVIA. MAXIMA OF 30-60MM ARE EXPECTED IN CENTRAL
BOLIVIA...RONDONIA...MATO GROSSO...AND NORTH MATO GROSSO DO SUL.
SOUTH AMAZON-BRASIL CAN ALSO EXPECT SIMILAR AMOUNTS. THE FRONTAL
BOUNDARY WILL FAVOR GENERALIZED MAXIMA OF 20-45MM IN SAO
PAULO...MINAS GERAIS...AND SOUTH RIO DE JANEIRO. BY
WEDNESDAY...THE FRONTAL BOUNDARY IS EXPECTED TO WEAKEN AND LEAVE
REMNANTS OVER SOUTHWEST BRASIL...BOLIVIA...AND PERU...AS IT WILL
BEGIN TO FEEL THE EFFECTS OF THE POTENT UPPER RIDGE THAT IS
STRENGTHENING INTO EASTERN BRASIL BY WEDNESDAY INTO THURSDAY.
HOWEVER..THE CONVERGING MOISTURE OVER THE REGION IS EXPECTED TO
CONTINUE WITH FLOW FROM THE EAST AND SOUTH. THIS FEATURE WILL
RESEMBLE THE SOUTH ATLANTIC CONVERGENCE ZONE (SACZ) BUT IT WILL
NOT LAST FOR TOO MANY DAYS. THE PERSISTENT PRESENCE OF MOISTURE
WILL CONTINUE AND FAVOR MAXIMA OF 35-70MM FROM RIO DE
JANEIRO/ESPIRITO SANTO THROUGH MINAS GERAIS...GOIAS...NORTH MATO
GROSSO AND PORTIONS OF SOUTH PARA. GENERALIZED MAXIMA OF 30-60MM
ARE EXPECTED FROM SOUTH PERU...ACRE..SOUTH AMAZONAS-BRASIL...AND
RONDONIA. OTHER REGIONS OF CENTRAL AND NORTH BRASIL CAN EXPECT
MAXIMA OF 25-50MM. ON THURSDAY...THE FRONTAL BOUNDARY REMNANTS
CONTINUE TO TRIGGER THE DEEP CONVECTION IN THE REGION.
HOWEVER...WINDS BEGIN TO SHIFT FROM NORTH TO SOUTH OVER PORTIONS
OF BOLIVIA. CONVERGENCE IS STILL EXPECTED OVER NORTH AND CENTRAL
BRASIL...WHERE MAXIMA OF 35-70MM COULD EXCEED LOCALLY. AMOUNTS OF
30-60MM ARE EXPECTED IN EAST AMAZONAS-BRASIL AND RONDONIA. WHILE
THE REST OF THE REGION CAN SEE LOCALIZED SCATTERED AMOUNTS BELOW
45MM.
IN THE SOUTHERN CONE OF THE CONTINENT...DUE TO THE PASSING OF THE
COLD FRONT ON TUESDAY...MOST OF THE REGION IN ARGENTINA AND
URUGUAY ARE EXPECTED TO REMAIN RELATIVELY DRY. THE EXCEPTION WILL
BE SOUTHERN CHILE THAT IS CURRENTLY SEEING THE PASSAGE OF A
FRONTAL BOUNDARY ON TUESDAY AFTERNOON. BY THE EVENING HOURS THE
FRONTAL BOUNDARY IS EXPECTED IN WEST ARGENTINA...AND EXTENDS INTO
THE PACIFIC OCEAN THROUGH CHILE. AN UPPER LEVEL JET OVER THE
SOUTHERN REGIONS OF CHILE WILL FAVOR VENTILATION WITH THE PASSING
OF THE FRONT IN THE LOWER LEVELS. EXPECT MAXIMA OF 20-35MM IN
AYSEN AND NORTH MAGALLANES. ON WEDNESDAY...A RIDGE IS EXPECTED TO
ENTER THE REGION...DEBILITATING THE POTENTIAL FOR HIGHER AMOUNTS
OF PRECIPITATION. YET...THE FRONTAL BOUNDARY CONTINUES TO FAVOR
MAXIMA OD 15-25MM IN SOUTH LS LAGOS CHILE INTO NORTH AYSEN. BY
THURSDAY...THE UPPER LEVEL CONDITIONS BEGINS TO SHIFT WITH THE
ENTRANCE OF THE NEXT UPPER TROUGH BY LATE WEDNESDAY INTO THURSDAY.
THE ASSOCIATED UPPER JET ENTERS PERPENDICULARLY OVER AYSEN AND LOS
LAGOS...AND THE DIFFLUENCE ASSOCIATED WITH THE TROUGH WILL FAVOR
FOR BETTER UPPER LEVEL DIVERGENCE IN THE REGION. IN THE LOWER
LEVELS...THE ATMOSPHERIC RIVER ENTERING THE REGION IS ASSOCIATED
WITH AMOUNTS OF PRECIPITABLE WATER OF OVER 25-30MM. THESE
CONDITIONS WILL FAVOR THE POTENTIAL FORM MAXIMA OF 30-60MM IN LOS
LAGOS AND NORTH AYSEN REGION...WITH POTENTIAL FOR HIGHER AMOUNTS
LOCALLY. IN THE SURROUNDING REGIONS OF LOS LAGOS AND
AYSEN...EXPECT MAXIMA OD 20-40MM WITH MOUNTAIN SNOW. MAGALLANES
CAN EXPECT MAXIMA OF 15-25MM WITH A CHANCE OF MOUNTAIN SNOW.
CASTELLANOS...(WPC)
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