762  
FXSA20 KWBC 301823  
PMDSA  
 
SOUTH AMERICA FORECAST DISCUSSION - INTERNATIONAL DESKS  
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD  
222 PM EDT FRI AUG 30 2024  
 
GFS DATA AT FTPPRD.NCEP.NOAA.GOV/PUB/DATA/NCCF/COM/GFS/PROD/  
 
SOUTH AMERICAN FORECAST BULLETIN FOR 30 AUG 2024 AT 1820 UTC:  
 
OVER THE NEXT 3 DAYS...A FEW EVENTS CAN BE EXPECTED ACROSS  
PORTIONS OF SOUTH AMERICA. ONE AREA IS OVER EASTERN ARGENTINA INTO  
URUGUAY...WHERE MODERATE TO HEAVY RAIN CAN BE EXPECTED TODAY AND  
SATURDAY...WITH A SLIGHT RISK OF SEVERE WEATHER OVER URUGUAY.  
ACROSS SOUTHERN CHILE...AN ATMOSPHERIC RIVER WILL AFFECT AREAS  
FROM BIO BIO SOUTH TO AYSEN...CAUSING AN INCREASE IN RAIN AND  
SNOWFALL ACROSS THE AREA...ESPECIALLY ON SATURDAY AND SUNDAY.  
THERE IS ALSO SOME SNOW AND RAIN MIX ACROSS BOLIVIA AND SOUTHERN  
PERU THAT COULD BE OBSERVED AS A COLD MID LEVEL TROUGH EXTENDS  
NORTH OVER THE AREA WITH ONSHORE FLOW.  
 
A LOW LEVEL JET OVER SOUTH AMERICA JUST EAST OF A COLD FRONT WILL  
INTERACT WITH A STATIONARY FRONT IN AND AROUND URUGUAY...CAUSING  
POOLING OF LOW LEVEL MOISTURE OVER THE AREA. THIS AREA WILL  
EVENTUALLY DEVELOP A LOW PRESSURE AND A WARM FRONT WILL DEVELOP  
AND PUSH SOUTHEAST INTO THE ATLANTIC WATERS BY SUNDAY. FOR TODAY  
AND SATURDAY...THERE WILL ALSO BE A MID AND UPPER LEVEL LOW  
PRESSURE THAT WILL MOVE INTO ARGENTINA...POSITIONING OVER THE  
COUNTRY BOUNDARY BETWEEN ARGENTINA AND URUGUAY BY SATURDAY  
EVENING. THE COMBINATION OF THE DEVELOPING SFC LOW WITH THE MID  
AND UPPER LEVEL LOW...WITH THE STRONG NORTHERLY WINDS AND  
RELATIVELY DEEP MOISTURE...WILL CAUSE SIGNIFICANT AMOUNTS OF RAIN  
TODAY INTO SATURDAY OVER THE AREA.  
BASED ONT EH LATEST GUIDANCE...THIS PATTERN WILL CAUSE RAINFALL  
WITH MAX VALUES NEAR 40-80MM OVER ARGENTINA AND URUGUAY...WHILE  
LOWER AMOUNTS OF RAIN CAN BE EXPECTED OVER NORTHERN URUGUAY...WITH  
MAX VALUES OF 20-40MM FORECAST FOR TODAY AND SATURDAY. THAT BEING  
SAID...THE BEST INSTABILITY IS EXPECTED OVER URUGUAY...AND THUS  
THERE IS A MODERATE RISK OF SEVERE WEATHER TODAY FOR PORTIONS OF  
URUGUAY AND ADJACENT AREAS...BUT THE RISK DECREASES DURING THE  
WEEKEND. BY SUNDAY INTO MONDAY...THE DEVELOPING LOW PRESSURE AND  
ASSOCIATED FRONTS ARE FORECAST TO MOVE OFFSHORE INTO THE ATLANTIC.  
 
SOUTH CENTRAL TO SOUTHERN CHILE IS EXPECTED TO HAVE AN EVENT WITH  
AN ATMOSPHERIC RIVER OVER THE NEXT FEW DAYS. THE PRECIPITABLE  
WATER IS EXPECTED TO INCREASE TO AS MUCH AS 25MM BY SATURDAY  
EVENING...AND OVER 30MM BY SUNDAY EVENING. THE ATMOSPHERIC RIVER  
IS EXPECTED TO GRADUALLY MOVE NORTH THROUGH THE WEEKEND...CAUSING  
THE INCREASE IN PRECIPITABLE WATER TO MOVE NORTH WITH EACH DAY  
THIS WEEKEND. THEREFORE...THE AREAS WITH SIGNIFICANT RAIN WILL BE  
MAINLY OVER AYSEN ON SATURDAY...WITH UP TO 70MM OF RAIN WITH SNOW  
IN THE HIGHER ELEVATIONS. ON SUNDAY...THE MOISTURE WILL BE HIGHER  
FURTHER NORTH...AFFECTING AREAS IN AND AROUND BIO BIO TO LAGOS ON  
SUNDAY...WITH MAX VALUES NEAR 25-50MM OF RAIN AND UP TO 30CM OF  
SNOW.  
 
THE AFOREMENTIONED MID LEVEL TROUGH THAT WILL EXTEND INTO BOLIVIA  
AND SOUTHERN PERU WILL CAUSE INCREASE IN MOISTURE AND COLD TEMPS  
OVER THE AREA ON SATURDAY AND SUNDAY. THIS COULD RESULT IN AREAS  
OF RAIN AND SNOW SHOWERS OVER WESTERN BOLIVIA AND SOUTHERN PERU.  
WITH ALL SNOW OVER THE HIGHEST ELEVATIONS AND A RAIN AND SNOW MIX  
OVER THE VALLEYS...ALTHOUGH THE AMOUNTS ARE NOT EXPECTED TO BE TOO  
SIGNIFICANT...WITH DAILY PRECIP MAX VALUES OF AROUND 15-20MM.  
 
ALAMO...(WPC)  
LOPEZ...(DMH PARAGUAY)  
PALAVECINO...(SMN ARGENTINA)  
 
NOTE...THE NEXT DISCUSSION WILL BE ON 3 SEPT 2024 DUE TO THE LABOR  
DAY HOLIDAY.  
 

 
 
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