867
FXSA20 KWBC 121925
PMDSA
SOUTH AMERICA FORECAST DISCUSSION - INTERNATIONAL DESKS
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
225 PM EST WED FEB 12 2025
GFS DATA AT FTPPRD.NCEP.NOAA.GOV/DATA/NCCF/COM/GFS/PROD/
SOUTH AMERICA FORECAST BULLETIN 11 FEB 2025 AT 1930 UTC
IN MID - LATITUDE SOUTH AMERICA...
IN NORTH ARGENTINA, URUGUAY, AND SOUTH BRASIL, A SURFACE COLD
FRONT, LOCATED ACROSS SOUTH URUGUAY AND NORTHERN ARGENTINA ON
WEDNESDAY AFTERNOON, WILL TRANSITION INTO A STATIONARY FRONT BY
FRIDAY EVENING AND WILL BE LOCATED ACROSS NORTH URUGUAY AND
SOUTHERN BRASIL AND DECAYING THEREAFTER. THE GREATEST
PRECIPITATION IMPACTS WILL OCCUR FROM WEDNESDAY MORNING THROUGH
THURSDAY MORNING. A MID-LEVEL SHORTWAVE TROUGH WILL BE TRAVERSING
THIS REGION WEDNESDAY AFTERNOON THROUGH THE EVENING. WE WILL ALSO
SEE AN INCREASE IN LOW LEVEL MOISTURE CONVERGENCE AND UPPER
DIVERGENCE IN THIS SAME TIME SPAN. THUS, CONVECTION WILL BE MORE
FAVORABLE STARTING WEDNESDAY AFTERNOON THROUGH THURSDAY MORNING,
YIELDING TO MAXIMUM PRECIPITATION TOTALS OF 30 - 60MM IN NORTHEAST
URUGUAY AND RIO GRANDE DO SUL. EXPECT MAXIMUM PRECIPITATION TOTALS
OF 20 - 35MM IN PARTS OF RIO DE LA PLATA AND CORDOBA-SANTA FE
REGIONS OF ARGENTINA FOR THIS SAME TIME PERIOD. BY THURSDAY
MORNING THROUGH FRIDAY MORNING, THE MOISTURE COUPLED WITH THE
STATIONARY FRONT WILL RAPIDLY PROPAGATE NORTHWARD INTO SOUTHEAST
BRASIL, WHERE UPPER DIVERGENCE AND MOISTURE CONTINUE TO BE
PLENTIFUL. THIS WILL YIELD TO MAXIMUM PRECIPITATION TOTALS OF 25 -
50MM FOR THURSDAY MORNING THROUGH FRIDAY MORNING ALONG THIS REGION.
OTHER SYSTEMS OF INTEREST IN ARGENTINA AND URUGUAY ARE A SERIES OF
LOW LEVEL TROUGHS AFFECTING THE REGION AFTER THURSDAY MORNING.
FROM THURSDAY MORNING THROUGH FRIDAY MORNING, A LOW LEVEL TROUGH
WILL DRAPE ACROSS CENTRAL ARGENTINA AND INTO SOUTHERN URUGUAY. IN
THE MID-LEVELS, EXPECT A SHORTWAVE TROUGH WITH ACCOMPANIED
VORTICITY ADVECTION AND A SUBTLE INCREASE IN LOW LEVEL MOISTURE
AFTER THURSDAY AFTERNOON AND INTO THE OVERNIGHT HOURS. A COOLING
OF THE MID-LEVELS WILL YIELD TO AN INCREASE IN INSTABILITY, WITH
SLIGHT RISK SEVERE WEATHER POSSIBLE ACROSS CORDOBA - SANTA FE, LA
PAMPA-BUENOS AIRES PROVINCE, AND RIO DE LA PLATA. EXPECT MAXIMUM
PRECIPITATION TOTALS OF 15 - 25MM IN THE CORDOBA - SANTA FE
PROVINCE AND LA PAMPA - BUENOS AIRES PROVINCE FOR THURSDAY MORNING
THROUGH FRIDAY MORNING. BY FRIDAY MORNING THROUGH SATURDAY
MORNING, ANOTHER TROUGH ACROSS NORTHERN CORDOBA - SANTA FE WILL
YIELD SIMILAR CONDITIONS IN THE REGION, AND ANTICIPATE MAXIMUM
PRECIPITATION TOTALS OF 20 - 40MM FOR FRIDAY MORNING THROUGH
SATURDAY MORNING.
ELSEWHERE, IN CHILE, EXPECT DAILY MAXIMUM PRECIPITATION TOTALS OF
15MM FOR THE NEXT THREE DAYS. A SERIES OF UPPER LEVEL TROUGHS AND
SURFACE FRONTS WILL CONTINUE TO DRIVE MOISTURE PLUMES INTO THE
COAST OF AUSTRAL CHILE.
IN TROPICAL SOUTH AMERICA...
IN THE UPPER LEVELS, A MORE EASTERLY FLOW IS EXPECTED TO DEVELOP
OVER THE REGION, AND WILL FAVOR AN INCREASE IN SPEED DIVERGENCE
AND DIFFLUENCE THROUGH SATURDAY MORNING. AREAS MOST IMPACTED BY
THIS REGIME WILL BE ECUADOR AND THE AMAZON BASIN, WHERE AN
ABUNDANCE OF MOISTURE CONVERGENCE WILL PREVAIL THROUGH FRIDAY
MORNING. THESE CONDITIONS WILL YIELD TO MAXIMUM RAINFALL TOTALS OF
35 - 70MM FOR EAST-CENTRAL PERU FROM WEDNESDAY MORNING THROUGH
THURSDAY MORNING. BY THURSDAY MORNING THROUGH FRIDAY MORNING, THE
EFFECTS OF UPPER DIVERGENCE WILL BE GREATER OVER THE REGION,
THOUGH MOISTURE CONVERGENCE WILL DECREASE BY LATE THURSDAY EVENING
ACROSS ECUADOR AND THE WEST AMAZON BASIN. EXPECT A MAXIMUM
PRECIPITATION TOTAL OF 35 - 70MM TO SPAN ACROSS PARTS OF THE
NORTHWEST AND WEST AMAZON BASIN FOR THURSDAY MORNING THROUGH
FRIDAY MORNING. ANTICIPATE A DRYING TREND THEREAFTER OVER THIS
REGION. BY FRIDAY MORNING THROUGH SATURDAY MORNING, AREAS OF
GREATEST PRECIPITATION IMPACT WILL BE ACROSS THE CENTRAL AMAZON
BASIN, WITH MAXIMUM PRECIPITATION TOTALS OF 25 - 50MM WILL BE
LIKELY.
IN ECUADOR, THE AFOREMENTIONED UPPER LEVEL REGIME AND LOW LEVEL
MOISTURE WILL BE THE MAIN DRIVING FORCE FOR PRECIPITATION PATTERNS
IN THE NEXT THREE DAYS. EXPECT THE HIGHEST MAXIMUM PRECIPITATION
TOTALS OF 30 - 60MM FOR WEDNESDAY MORNING THROUGH THURSDAY
MORNING. IN THE LOW LEVELS, THOUGH A MORE SOUTHERLY WIND FLOW WILL
BEGIN TO IMPACT THE COAST, THE ITCZ WILL CONTINUE TO FAVOR
MOISTURE CONVERGENCE IN THIS REGION. DO EXPECT A SUBTLE DAILY
DECREASE IN MAXIMUM PRECIPITATION TOTALS.
ANOTHER REGION OF INTEREST IS EAST-CENTRAL BOLIVIA STARTING
THURSDAY MORNING. AN UPPER TROUGH SITUATED ACROSS CENTRAL BOLIVIA
WEDNESDAY AFTERNOON WILL REMAIN SEMI-STATIONARY OVER THIS REGION
THROUGH THE NEXT THREE DAYS. THE TROUGH WILL FAVOR UPPER
DIFFLUENCE WHILE THE LOW LEVEL MOISTURE CONVERGENCE WILL BE
PRESENT STARTING THURSDAY AFTERNOON THROUGH FRIDAY AFTERNOON.
HIGHEST MAXIMUM PRECIPITATION TOTALS OF 25 - 50MM ARE EXPECTED FOR
THURSDAY MORNING THROUGH FRIDAY MORNING IN CENTRAL BOLIVIA.
ELSEWHERE IN TROPICAL SOUTH AMERICA, THE ITCZ, NET, AND SOUTHERN
ITCZ WILL CONTINUE TO BE OF INFLUENCE IN PRECIPITATION PATTERNS
ACROSS THE REGION. DO NOTE THAT THE ATLANTIC SOUTHERN ITCZ WILL
LOSE ITS DEFINITION BY FRIDAY MORNING INTO SATURDAY MORNING. ALSO,
A SERIES OF LOW LEVEL TROUGHS WILL HELP ENHANCE PRECIPITATION
CHANCES IN THE NORTHEAST REGIONS AND ACROSS THE CENTRAL-SOUTHEAST
COAST OF BRASIL.
MORALES...(WPC)
CASTELLANOS...(WPC)
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