754  
FXSA20 KWBC 112006  
PMDSA  
 
SOUTH AMERICA FORECAST DISCUSSION - INTERNATIONAL DESKS  
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD  
406 PM EDT THU JUL 11 2024  
 
GFS DATA AT FTPPRD.NCEP.NOAA.GOV/PUB/DATA/NCCF/COM/GFS/PROD/  
 
SOUTH AMERICAN FORECAST BULLETIN FOR 09 JUL 2024 AT 2000 UTC:  
IN THE CENTRAL PORTIONS OF THE CONTINENT ON THURSDAY...AN UPPER  
LEVEL TROUGH IS POSITIVELY TILTED OVER CENTRAL CHILE AND  
ARGENTINA...AND EXTENDS INTO SOUTHERN PERU AND CENTRAL BOLIVIA. TO  
THE EAST OF THE TROUGH...THE COUPLING OF THE SUBTROPICAL JET AND  
THE NORTH POLAR JET IS ASSISTING WITH UPPER DIVERGENCE OVER  
PARAGUAY...AND RIO GRANDE DO SUL AND SANTA CATARINA IN BRASIL. THE  
MOISTURE CONTENT OVER THE REGION IS EXPECT TO REMAIN LOW...WHERE  
PRECIPITABLE WATER LEVELS ARE EXPECTED TO REMAIN BELOW 40MM. IN  
THE MID LEVELS...THE TROUGH OVER THE REGION HAS THREE NOTABLE  
SHORT WAVE TROUGHS THAT ARE EXPECTED TO PROPAGATE INTO SOUTHERN  
PARAGUAY AND INTO SOUTH BRASIL...ALLOWING FOR FAVORABLE  
CONVECTION. HOWEVER...DUE TO THE LOW MOISTURE CONTENT IN THE LOWER  
LEVELS...AMOUNTS OF PRECIPITATION ARE NOT EXPECTED TO EXCEED 50MM  
IN ALONG A TROUGH FROM EAST PARAGUAY...INTO SANTA CATARINA/RIO  
GRANDE DO SUL. IN CENTRAL PERU AND BOLIVIA...THE MOISTURE ADVECTED  
INTO THE REGION WILL FAVOR GENERALIZED MAXIMA OF 15 TO 35MM. ON  
FRIDAY...THE MID TO UPPER LEVEL TROUGH IS EXPECTED TO  
WEAKEN...WHILE THE SUBTROPICAL JET BECOMES ZONAL FROM NORTHERN  
CHILE INTO SOUTHERN BRASIL. IN ADDITION...THE SUPPORT FROM THE  
LOWER LEVELS IS EXPECTED TO DECREASE ACROSS THE REGION...AND  
AMOUNTS OF PRECIPITATION IS ALSO EXPECTED TO DECREASE. THE REGION  
WITH THE HEAVIEST PRECIPITATION IS EXPECTED OVER SANTA  
CATARINA-BRASIL...WHERE EXPECT MAXIMA OF 20-35MM. ELSEWHERE IN THE  
CENTRAL PORTION OF THE CONTINENT...MAXIMA ARE EXPECTED TO REMAIN  
BELOW 20MM. BY SATURDAY...ANOTHER MID TO UPPER LEVEL TROUGH IS  
EXPECTED FROM CHILE INTO URUGUAY. THE DIVERGENT SIDE OF THE  
TROUGH...WILL FAVOR THE DYNAMICS FOR MAXIMA OF 25-50MM IN PARANA  
AND SANTA CATARINA IN BRASIL...AS WELL AS EAST PARAGUAY. LOWER  
AMOUNTS OF 20-35MM ARE EXPECTED IN SOUTHERN SANTA CATARINA INTO  
RIO GRANDE DO SUL. THE DECREASE IN PRECIPITATION CONTINUES IN THE  
MOUNTAIN REGIONS OF PERU...WHERE EXPECT MAXIMA BELOW 15MM.  
 
IN THE SOUTHERN PORTION OF THE CONTINENT...A BLOCKING PATTERN  
CONTINUES TO FAVOR DRIER CONDITIONS IN CHILE AND ARGENTINA. AS  
SUCH...MUCH OF THE FRONTAL PASSAGES ARE REMAINING TO THE SOUTH OF  
THE CONTINENT AND ARE EXPECTED TO MAKE IT INTO THE TIERRA DEL  
FUEGO AND DRAKE PASSAGE REGION BY SATURDAY. HOWEVER...DUE TO THE  
LOW MOISTURE CONTENT AND LACK OF FAVORABLE DYNAMICS IN THE UPPER  
LEVELS...MAXIMA OF 15MM ARE EXPECTED ON FRIDAY AND SATURDAY.  
OTHERWISE...EXPECT DRY CONDITIONS OVER THE NEXT THREE DAYS.  
 
IN TROPICAL SOUTH AMERICA...THE PROPAGATION OF TROUGHS AND  
TROPICAL WAVES ALONG THE ITCZ/NET IS EXPECTED TO FAVOR  
PRECIPITATION IN THE REGION. EXPECT MAXIMA OF 20-40MM IN VENEZUELA  
AND COLOMBIA ON THURSDAY. MAXIMA OF 30-60MM IS EXPECTED OVER SOUTH  
COLOMBIA AND EAST ECUADOR. NORTH PERU CAN EXPECT MAXIMA OF  
20-35MM. ON SATURDAY...VENEZUELA AND ECUADOR/NORTH PERU CAN EXPECT  
MAXIMA OF 20-40MM.  
 
ACOSTA..(WPC)  
 

 
 
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