738   
FXSA20 KWBC 111947  
PMDSA   
  
SOUTH AMERICA FORECAST DISCUSSION - INTERNATIONAL DESKS  
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD  
346 PM EDT WED SEP 11 2024  
  
GFS DATA AT FTPPRD.NCEP.NOAA.GOV/PUB/DATA/NCCF/COM/GFS/PROD/  
  
SOUTH AMERICAN FORECAST BULLETIN FOR 11 SEP 2024 AT 1945 UTC:  
  
AN ADVANCING FRONT EXTENDS FROM NORTHWEST ARGENTINA..INTO EAST  
ARGENTINA...AND CROSSES INTO THE BORDER BETWEEN NORTHEAST URUGUAY  
AND BRASIL ON WEDNESDAY. IN THE UPPER LEVELS...AN UPPER TROUGH IS  
LOCATED OVER MOST OF SOUTH AND CENTRAL ARGENTINA...WITH A JET  
EXTENDING FROM THE NORTHERN REGION INTO URUGUAY. EXPECT FAVORABLE  
UPPER DIVERGENCE CONDITIONS OVER PORTIONS OF URUGUAY DURING THE  
DAY ON WEDNESDAY. AS THE DAY PROGRESSES...THE UPPER TROUGH  
CONTINUES TO PUSH NORTHWARD...GIVING WAY FOR THE NORTHERN MOVEMENT  
OF THE FRONT INTO CENTRAL PARAGUAY...MISIONES-ARGENTINA...AND RIO  
GRANDE DO SUL-BRASIL BY WEDNESDAY EVENING. THE ARE OF MAXIMUM  
DIVERGENCE IS EXPECTED TO MOVE INTO PORTIONS OF NORTH ARGENTINA  
INTO SOUTH PARAGUAY...DUE TO THE PASSING OF SHORT WAVE TROUGHS IN  
THE MID AND UPPER LEVELS OF THE ATMOSPHERE. THIS REGION CAN EXPECT  
A MODERATE RISK OF SEVERE WEATHER IS EXPECTED. MAXIMA OF 20-35MM  
ARE EXPECTED FROM FORMOSA-ARGENTINA...SOUTH PARAGUAY...RIO GRANDE  
SO SUL...AND URUGUAY. ON THURSDAY...THE FRONT IS EXPECTED TO  
CONTINUE MOVING NORTHWARD AND FINALLY BECOME STATIONARY FROM  
SOUTHERN BOLIVIA...INTO THE BORDER REGION BETWEEN PARAGUAY AND  
BRASIL...AND EXTENDING INTO PARANA...SANTA CATARINA...IN BRASIL.  
AND INCREASE IN MOISTURE IN THE LOWER LEVELS WILL FAVOR AN  
INCREASE IN PRECIPITATION OVER REGIONS OF SOUTH  
PARAGUAY...CORRIENTES...AND MISIONES...WHERE EXPECT MAXIMA OF  
30-60MM. THE MOVEMENT OF THE UPPER JET AND MID TO UPPER LEVEL  
TROUGH TOWARDS THE NORTH WILL SEE AN INCREASE IN DIFFLUENCE OVER  
THE REGION OF SOUTH PARAGUAY INTO SOUTH BRASIL. WITH THE  
PROPAGATION OF SHORT WAVE TROUGHS EMBEDDED IN THE MID TO UPPER  
LEVEL OF THE ATMOSPHERE...EXPECT ENHANCE DEEP CONVECTION...AND A  
MODERATE RISK OF SEVERE WEATHER. THESE CONDITIONS WILL EXTEND INTO  
RIO GRANDE DO SUL AND SANTA CATARINA...WHERE EXPECT MAXIMA OF  
20-45MM AND A MODERATE RISK OF SEVERE WEATHER. BY FRIDAY...THE  
FRONTAL BOUNDARY REMAINS IN SOUTH BOLIVIA AND PORTIONS OF  
PARAGUAY/BRASIL...AND MOVES INTO SOUTHERN SAO PAULO. MOISTURE IS  
EXPECTED TO INCREASE OVER THE REGION INTO CENTRAL BOLIVIA...AND  
EXTENDS INTO SOUTHEAST BRASIL. INCREASED DIFFLUENCE ASSOCIATED  
WITH THE UPPER LEVEL JET WILL FAVOR INCREASED DIVERGENCE OVER  
PORTIONS OF SOUTH PARAGUAY...AND INTO SOUTHERN BRASIL. THE SHORT  
WAVE TROUGHS WILL CONTINUE TO PROPAGATE OVER THE REGION ON FRIDAY.  
WITH THE CONTRAST OF TEMPERATURE AND MOISTURE IN THE REGION...AS  
WELL AS THE AFOREMENTIONED CONDITIONS...EXPECT THE RISK OF  
SEVERITY TO CONTINUE OVER SOUTHERN  
BOLIVIA...PARAGUAY...MISIONES...AND EXTREME SOUTH BRASIL. IN TERMS  
OF PRECIPITATION...THE MAXIMA OF 30-60MM IS EXPECTED IN SOUTH  
PARAGUAY...WHERE PRECIPITABLE WATER LEVELS ARE EXPECTED ABOVE  
40MM...WHERE EXPECT A MODERATE RISK OF SEVERE WEATHER. FROM  
CENTRAL BOLIVIA...INTO NORTH PARAGUAY...AND NORTH RIO GRANDE DO  
SUL...SANTA CATARINA...AND PARANA CAN EXPECT MAXIMA OF 20-35MM  
WITH A SLIGHT RISK OF SEVERE WEATHER.  
  
OVER THE SOUTHERN PORTION OF THE CONTINENT...OF INTEREST IS ON  
WEDNESDAY...WHERE AN ATMOSPHERIC RIVER WILL MAKE ITS WAY OVER  
SOUTHERN CHILE AND SOUTH ARGENTINA...WHERE PRECIPITABLE WATER  
AMOUNTS OF BETWEEN 10-20MM ARE EXPECTED IN AYSEN AND MAGALLANES.  
AS THIS PROPAGATES OVER THE REGION...AN UPPER LEVEL TROUGH WILL  
ENHANCE THE DEVELOPMENT OF PRECIPITATION IN AYSEN AND MAGALLANES.  
COLD AIR ENTERING WITH THE FRONTAL BOUNDARY WILL FAVOR THE MIX  
SNOW AND RAIN IN MAGALLANES ON WEDNESDAY. EXPECT MAXIMA OF 15-25MM  
IN SOUTH AYSEN AND NORTH MAGALLANES. EXTREME SOUTH AYSEN CAN  
EXPECT AMOUNTS BELOW 15MM WITH A MIX OF RAIN AND SNOW. ON  
THURSDAY...THE FRONTAL BOUNDARIES ADVANCE NORTHWARD AND WILL FAVOR  
PRECIPTIATION IN THE REGION OF SOUTH CHILE. THE AMOUNTS OF  
PRECIPITABLE WATER ARE EXPECTED TO DECREASE...AS SUCH...MAXIMA OF  
15-20MM ARE EXPECTED IN AYSEN. TO THE SOUTH...COLDER AIR ENTERS  
INTO MAGALLANES...WHERE SNOWFALL MAXIMA OF 05-10CM COULD BE  
FAVORED. BY FRIDAY...CONDITIONS ARE EXPECTED TO BECOME DRIER OVER  
SOUTH CHILE AND TRACE AMOUNTS OF PRECIPITATION ARE EXPECTED.  
  
ACOSTA...(WPC)  
  
 
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