722  
FXSA20 KWBC 241954  
PMDSA  
 
SOUTH AMERICA FORECAST DISCUSSION - INTERNATIONAL DESKS  
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD  
254 PM EST MON FEB 24 2025  
 
GFS DATA AT FTPPRD.NCEP.NOAA.GOV/DATA/NCCF/COM/GFS/PROD/  
 
SOUTH AMERICA FORECAST BULLETIN 24 FEB 2025 AT 2000UTC:  
 
IN THE LARGE SCALE...  
THE MADDEN JULIAN OSCILLATION (MJO) HAS BEEN CLASSIFIED AS BEING  
IN ITS PHASE 8, INDICATING AN INCREASE IN UPPER LEVEL DIVERGENCE  
ACROSS THE WESTERN HEMISPHERE. HOWEVER, THE MJO IS BEING OBSERVED  
AS BEING UNORGANIZED. IN THE NEXT WEEK, MODELS ARE INDICATING A  
SHIFT TO A MORE CONVERGENT PHASE.  
 
IN THE UPPER LEVELS...  
THE BOLIVIAN HIGH, LOCATED NEAR 21S 80W MONDAY AFTERNOON, WILL  
CONTINUE TO WEAKEN THROUGH TUESDAY AFTERNOON. IN SOUTHEAST BRASIL,  
AN UPPER TROUGH, WITH AN AXIS ACROSS 21S 44W AND 35S 27W, WILL  
REMAIN STATIONARY OVER THE AREA THROUGH THE NEXT THREE DAYS, AND  
MAY OCCLUDE BY THE END OF THIS WEEK. THE INTERACTION BETWEEN THESE  
TWO UPPER LEVEL FEATURES WILL YIELD TO AN INCREASE OF DIFFLUENCE  
ACROSS NORTHEAST ARGENTINA, PARAGUAY, URUGUAY, AND SOUTH BRASIL  
THROUGH TUESDAY AFTERNOON.  
 
IN MID - LATITUDE SOUTH AMERICA...  
IN AUSTRAL CHILE, THE PERIOD OF GREATEST PRECIPITATION IMPACT WILL  
BE MONDAY THROUGH TUESDAY MORNING. DURING THIS PERIOD, AN UPPER  
JET STREAK WILL BE TRAVERSING ACROSS THE REGION, SUSTAINING UPPER  
DIVERGENCE THROUGH MONDAY EVENING. IN THE MID-LEVELS, A TROUGH  
ACCOMPANIED BY VORTICITY ADVECTION WILL ALSO FAVOR ASCENT FOR  
CONVECTION. IN THE LOWER LEVELS, EXPECT AMPLE MOISTURE THROUGH  
TUESDAY MORNING. HOWEVER, LOW LEVEL WIND SPEEDS WILL DECREASE  
STARTING BY MONDAY EVENING, YIELDING TO A REDUCTION IN MOISTURE  
CONVERGENCE AND OROGRAPHIC EFFECTS THEREAFTER. THESE CONDITIONS  
WILL FAVOR A TOTAL PRECIPITATION MAXIMA OF 20 - 35MM THROUGH  
TUESDAY MORNING.  
 
IN ARGENTINA, FOR THE NEXT TWO DAYS, A LOW LEVEL MEANDERING TROUGH  
WILL REMAIN ACROSS NORTH - CENTRAL ARGENTINA AND URUGUAY. ALONG  
AND AHEAD OF THE TROUGH, MOISTURE CONVERGENCE WILL BE FAVORABLE.  
IN THE MID - LEVELS, A SERIES OF SHORTWAVE TROUGHS WILL ALSO HELP  
SUSTAIN CONVECTION WITHIN THIS REGION. THE PERIOD OF GREATEST  
PRECIPITATION IMPACT WILL BE MONDAY THROUGH WEDNESDAY MORNING. THE  
UPPER LEVEL SET UP FOR THIS PERIOD ARE AS FOLLOWS. FROM MONDAY  
MORNING THROUGH TUESDAY MORNING, UPPER LEVEL DIFFLUENCE AND SPEED  
DIVERGENCE WILL BE PRESENT ACROSS NORTH - CENTRAL ARGENTINA. BY  
TUESDAY MORNING THROUGH WEDNESDAY MORNING, UPPER DIFFLUENCE WILL  
DECREASE, BUT SPEED DIVERGENCE WILL REMAIN FAVORABLE. EXPECT TOTAL  
PRECIPITATION MAXIMA OF 25 - 50MM FOR MONDAY TO TUESDAY AND 30 -  
60MM FOR TUESDAY TO WEDNESDAY.  
 
IN TROPICAL SOUTH AMERICA ...  
 
IN THE UPPER LEVELS, WITH THE WEAKENING OF THE BOLIVIAN HIGH,  
UPPER LEVEL DIVERGENCE WILL DECREASE ACROSS WEST SOUTH AMERICA. IN  
ITS WAKE, AN UPPER TROUGH IS ANTICIPATED TO DEVELOP AFTER TUESDAY  
AFTERNOON AT 13S 78W, THOUGH IT IS EXPECTED TO QUICKLY WEAKEN AS  
IT INTERACTS WITH A SUB-TROPICAL TROUGH BY FRIDAY. ELSEWHERE IN  
THE REGION, UPPER EASTERLIES IN NORTHWEST SOUTH AMERICA WILL BEGIN  
TO WEAKEN STARTING TUESDAY MORNING, WHEN WESTERLIES WILL BEGIN TO  
DOMINATE THE WEST COAST REGIONS OF ECUADOR AND COLOMBIA. IT IS  
IMPORTANT TO NOTE THAT DIRECTIONAL WIND SHEAR WILL ALSO INCREASE  
AFTER TUESDAY MORNING IN THIS REGION, ACTING AS A LIMITING FACTOR  
FOR CONVECTIVE UPWARD DEVELOPMENT. HOWEVER, AMPLE MOISTURE  
CONVERGENCE WILL REMAIN THROUGH WEDNESDAY.  
 
IN THE LOW - LEVELS, ACROSS THE WEST COAST OF ECUADOR AND  
COLOMBIA, BEGINNING ON MONDAY AFTERNOON, TWO LOW LEVEL TROUGHS ARE  
DEVELOPING TO THE NORTH AND SOUTH OF THE EQUATOR RESPECTIVELY,  
BETWEEN 90W AND 100W STARTING MONDAY AFTERNOON. EXPECT AN INCREASE  
IN LOW LEVEL WESTERLIES TO CONVERGE ACROSS THE ECUADORIAN COAST  
THROUGH TUESDAY AFTERNOON. BY WEDNESDAY, THE TWO TROUGHS WILL  
CONTINUE TO MOVE WEST INTO THE CENTRAL PACIFIC, WITH LOW LEVEL  
WIND DIRECTION SHIFTING TO A MORE NORTHERLY COMPONENT ALONG THE  
PACIFIC COASTS OF COLOMBIA AND ECUADOR THEREAFTER. EXPECT A TOTAL  
PRECIPITATION MAXIMA OF 25 - 50MM FOR MONDAY THROUGH TUESDAY  
MORNING, A MAXIMA OF 30 - 60MM FROM TUESDAY MORNING THROUGH  
WEDNESDAY MORNING, AND 25 - 50MM MAXIMA FOR WEDNESDAY MORNING  
THROUGH THURSDAY MORNING.  
 
THE ITCZ, NET, AND SOUTHERN ITCZ WILL CONTINUE TO BE THE MAIN  
DRIVING FORCE FOR CONVECTION ACROSS THE REGION. REGIONS OF  
INTEREST CONTINUE TO BE THE NORTHWEST SECTION OF TROPICAL SOUTH  
AMERICA AND NORTHEAST SOUTH AMERICA. SIMILARLY, A SERIES OF LOW  
LEVEL TROUGHS WILL CONTINUE TO TRAVERSE THE REGION THROUGH THE  
NEXT THREE DAYS, INCREASING THE POTENTIAL FOR PRECIPITATION.  
 
MORALES...(WPC)  
LEDESMA...(WPC)  
 

 
 
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