SOUTH AMERICA FORECAST DISCUSSION - INTERNATIONAL DESKS
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
735 PM EDT MON AUG 26 2024

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

SOUTH AMERICAN FORECAST BULLETIN FOR 26 AUG 2024 AT 2325 UTC:

MOST OF THE SOUTH AMERICAN CONTINENT IS EXPECTED TO REMAIN
RAIN-FREE OVER THE NEXT FEW DAYS. THE EXCEPTIONS WOULD BE PORTIONS
OF SOUTHERN CHILE...A FEW SECTIONS OF SOUTHEASTERN ARGENTINA...AND
MANY SECTORS OF VENEZUELA...COLOMBIA AND PERU. OUT OF THESE
SECTORS...SOUTHERN CHILE HAS A CHANCE OF A MIX OF RAIN AND
SNOW...WHILE NORTHWESTERN SOUTH AMERICA WILL HAVE SHOWERS AND
THUNDERSTORMS EACH DAY INTO MIDWEEK. EVEN THOUGH OUR SURFACE
CHARTS DO SHOW SOME SURFACE TROUGHS OVER THE SOUTH AMERICAN
CONTINENT...AS WELL AS A FEW FRONTAL BOUNDARIES AND SHEAR LINES
OVER SMALL SECTIONS...MOST OF THE FRONTAL BOUNDARIES AND STRONG
WINDS IN THE CHARTS ARE LOCATED OVER THE WATERS.

TONIGHT INTO EARLY TUESDAY...PORTIONS OF NORTHERN PERU...EASTERN
ECUADOR AND SOUTHERN COLOMBIA ARE FORECAST TO OBSERVE NEAR 10-20MM
WITH MAX VALUES UP TO 60MM. THIS IS DUE TO THE REMNANTS OF AN OLD
FRONTAL BOUNDARY THAT KEEPS MOVING NORTH AS IT WEAKENS.
HOWEVER...IT WILL STILL BRING AN INCREASE OF LOCALIZED MOISTURE TO
THE AREA...CAUSING SHOWERS AND THUNDERSTORMS TO DEVELOP OVER THE
AREA. THERE IS ALSO A SHEAR LINE THAT EXTENDS FROM EAST CENTRAL
BRAZIL TO NORTHWESTERN BRAZIL. THIS SHEAR LINE IS CAUSING SOME
CONVECTION ALONG IT...PARTICULARLY OVER NORTHWESTERN BRAZIL INTO
SOUTHERN VENEZUELA. ELSEWHERE IN SOUTH AMERICA...THE TAIL END OF A
COLD FRONT AND A PRE-FRONTAL TROUGH ARE SKIRTING THE EAST CENTRAL
COAST OF BRAZIL. THIS WILL BRING SOME MOISTURE TO THE AREA AND
THEREFORE HELP THE DEVELOPMENT OF SOME SHOWER ACTIVITY ALONG THE
EAST CENTRAL COAST OF BRAZIL FROM THE COAST OF RIO DE
JANEIRO...NORTH INTO SOUTHERN BAHIA. THE OTHER NOTEWORTHY
PRECIPITATION WOULD BE IN CHILE OVER PORTIONS OF SOUTHERN AYSEN
AND NORTHERN MAGALLANES...WHERE A RAIN AND SNOW MIX COULD
ACCUMULATE TO AS MUCH AS 20MM TODAY. MEANWHILE ACROSS AREAS IN AND
AROUND   RIO NEGRO AND CHUBUT IN ARGENTINA WOULD OBSERVE SOME RAIN
AND RAIN AND SNOW MIX BUT ACCUMULATIONS WILL BE MINIMAL.

FOR TUESDAY INTO EARLY WEDNESDAY...THE AMOUNT OF RAIN IN THE
FORECAST INCREASES FOR THE REGION OF BAHIA IN EASTERN
BRAZIL...WITH THE FORECAST SUGGESTING MAX TOTALS OF UP TO 20 MM ON
THE SOUTHERN PORTION OF THE REGION BUT STILL UP TO 10 MM ON THE
NORTHERN PORTION OF THAT EASTERN COAST OF BAHIA. ACROSS THE REST
OF THE SOUTH AMERICAN CONTINENT...THE AMOUNT OF FORECAST RAINFALL
REMAINS FAIRLY MODEST. FOR NORTHERN SOUTH AMERICA...THERE IS A
TROPICAL WAVE THAT IS REACHING THE GUIANAS AND ALSO A TROUGH OVER
VENEZUELA. HOWEVER...THE FORECAST RAINFALL AMOUNTS FOR THE GUIANAS
WILL BE GENERALLY BETWEEN 5 AND 10 MM WITH MAX AMOUNTS OF
25MM...WHILE PORTIONS OF VENEZUELA AND PERHAPS EASTERN COLOMBIA
COULD OBSERVE UP TO 35 MM. THERE IS A COLD FRONT APPROACHING THE
SOUTHERN REGION OF CHILE PARTICULARLY FROM AYSEN TO
MAGALLANES...WHERE THERE IS A CHANCE OF A MIX OF RAIN AND SNOW AND
THE AMOUNTS OF PRECIPITATION COULD BE BETWEEN 10 AND 15 MM WITH
MAX VALUES UP TO 35 MM. THIS IS DUE TO DIRECT ONSHORE FLOW COMING
IN WITH SOME MOISTURE INTERACTING WITH THE TERRAIN. A VERY SMALL
PORTION OF SOUTHERN BRAZIL...NEAR SANTA CATARINA...COULD OBSERVE
LIGHT RAIN...AS WELL AS SOME PORTIONS OF PERU AND BOLIVIA...BUT
THE AMOUNT OF RAIN IS EXPECTED TO BE MINIMAL WITH NO SIGNIFICANT
ACCUMULATION.

LITTLE CHANGE IS EXPECTED ACROSS THE CONTINENT FROM WEDNESDAY INTO
THURSDAY. THERE IS HOWEVER AN INCREASE OF RAINFALL EXPECTED OVER
BAHIA IN EASTERN BRAZIL...WHERE MAX AMOUNTS OF RAIN BETWEEN 20 AND
40 MM ARE FORECAST...AS A WEAKENING  COLD FRONT MOVES ACROSS THE
ATLANTIC AND AFFECTS THE EASTERN SHORE OF THE REGION...AND ONSHORE
WIND FLOW PUSHES MOISTURE TO THE AREA. ACROSS NORTHERN SOUTH
AMERICA...THE TROPICAL WAVE IS EXPECTED TO BE APPROACHING EASTERN
VENEZUELA....AND A SURFACE TROUGH WOULD BE OVER WESTERN VENEZUELA
INTO EASTERN COLOMBIA. THE EXPECTED RAINFALL OVER NORTHERN SOUTH
AMERICA IS THAT OF 05-10MM WITH MAX VALUES UP TO 30MM OVER THE
GUIANAS...WHILE VENEZUELA AND COLOMBIA WOULD HAVE AMOUNTS UP TO
20MM. SOUTHERN CHILE WOULD REMAIN OBSERVING THE DIRECT COLD
ONSHORE FLOW FROM THE SOUTHERN PACIFIC AS A SURFACE HIGH PRESSURE
IS EXPECTED TO BE LOCATED JUST WEST OF SOUTH CENTRAL CHILE. THIS
SETUP WILL ONCE AGAIN CAUSE SOME RAIN AND SNOW MIX OVER THE
SOUTHERN PORTIONS OF CHILE...THIS TIME WITH PRECIPITATION
ACCUMULATIONS NEAR 05-10MM WITH MAX VALUES UP TO 15MM.


ALAMO...(WPC)
LOPEZ...(DMH PARAGUAY)
PALAVECINO (SMN ARGENTINA)