929
FXSA20 KWBC 052012
PMDSA
SOUTH AMERICA FORECAST DISCUSSION - INTERNATIONAL DESKS
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
311 PM EST WED FEB 05 2025
GFS DATA AT FTPPRD.NCEP.NOAA.GOV/PUB/DATA/NCCF/COM/GFS/PROD/
SOUTH AMERICAN FORECAST BULLETIN FOR 05 FEB 2025 AT 2000 UTC:
OVER THE NEXT THREE DAYS THERE WILL BE A FAVORABLE PATTERN FOR
THUNDERSTORM DEVELOPMENT OVER MUCH OF TROPICAL SOUTH
AMERICA...WITH THE AMAZONAS REGION OF BRASIL HAVING THE HIGHEST
ACCUMULATION OF RAIN OVER THE NEXT FEW DAYS ACCORDING TO THE MODEL
GUIDANCE. THIS WILL BE DUE TO FAVORABLE UPPER LEVEL DIFFLUENCE
COMBINED WITH DEEP MOISTURE AND CONVERGENCE IN THE LOWER LEVELS.
FRIDAY INTO SATURDAY LOOKS TO BE THE RAINIEST PERIOD OVER AMAZONAS
WITH AS MUCH AS 40-80MM OF RAIN POSSIBLE IN SOME AREAS. OTHER
AREAS ACROSS NORTHERN SOUTH AMERICA WILL HAVE THUNDERSTORMS THAT
WILL BE STRONGLY INFLUENCED BY THE DIURNAL HEATING...LOW LEVEL
TROUGHS AND THE OROGRAPHIC EFFECTS. THAT SAID...PORTIONS OF
NORTHERN PARA AND OVER AMAPA OF BRASIL ARE FORECAST TO OBSERVE
SOME RAIN TODAY AND THURSDAY...WITH DAILY MAXIMA NEAR 25MM AND
35MM RESPECTIVELY...BUT DEEPER MOISTURE WILL MOVE IN ON
FRIDAY...AND UP TO 40-80MM OF RAIN IS FORECAST FOR FRIDAY INTO
SATURDAY MORNING.
WITH RESPECT TO MOISTURE...THE AFOREMENTIONED MOISTURE OVER
AMAZONAS WILL BE NEAR NORMAL TO SLIGHTLY ABOVE NORMAL OVER THE
NEXT FEW DAYS. HOWEVER...EASTERN BRASIL...FROM RIO DE JANEIRO TO
THE NORTHWEST INTO THE BOUNDARY BETWEEN TOCANTINS...PARA...AND
MATO GROSSO...WILL HAVE MUCH BELOW NORMAL MOISTURE OVER THE NEXT
FEW DAYS...AND THEREFORE THE FORECAST IS FAIRLY DRY FOR THAT
REGION. ACROSS SOUTHERN SOUTH AMERICA...SLIGHTLY BELOW NORMAL
MOISTURE IS EXPECTED TODAY THROUGH THURSDAY...BUT AN ATMOSPHERIC
RIVER WILL BE MOVING IN VERY LATE THURSDAY INTO FRIDAY...CAUSING
POSITIVE MOISTURE ANOMALIES THROUGH FRIDAY ACROSS SOUTHERN CHILE
AND ARGENTINA. FOR THIS REASON...THE CHANCES OF RAIN INCREASE
ACROSS SOUTHERN CHILE...AND NOTABLY FOR SOUTHERN ARGENTINA.
ACROSS THE CONTINENT...THE UPPER LEVELS WILL HAVE A HIGH PRESSURE
IN THE PACIFIC TO THE WEST OF SOUTHERN PERU AND NORTHERN CHILE.
THERE IS ANOTHER HIGH PRESSURE OVER NORTHERN CHILE AND
NORTHWESTERN ARGENTINA. AN UPPER TROUGH WITH AXIS OVER EASTERN
ARGENTINA INTO BUENOS AIRES TONIGHT WILL CONTINUE TO MOVE EAST.
STRONG UPPER LEVEL WINDS ACROSS SOUTHERN SOUTH AMERICA...NEAR
140-150 KT ARE EXPECTED INTO THURSDAY...WEAKENING TO AROUND 120 KT
BY FRIDAY INTO THE WEEKEND. AN UPPER LOW OVER NORTHEASTERN BRASIL
IS DRIFTING SOUTHWEST...CONTRIBUTING TO RELATIVELY STRONG WINDS
OVER THE EASTERN TO SOUTHEASTERN STATES OF BRASIL.
IN THE MID LEVELS...A TROUGH THAT IS VERTICALLY STACKED WITH THE
AFOREMENTIONED UPPER TROUGH HAS AN AXIS OVER THAT WILL PASS BUENOS
AIRES TONIGHT AND EXIT URUGUAY BY THURSDAY MORNING. A MID LEVEL
LOW IS ALSO MOVING INTO SOUTHERN SOUTH AMERICA TONIGHT...EXITING
INTO THE ATLANTIC BY THURSDAY MORNING. A WEAK TROUGH WILL MOVE
INTO SOUTHERN SOUTH AMERICA ON FRIDAY AFTERNOON...EXITING ON
SATURDAY MORNING. THERE IS ALSO A PAIR OF HIGH PRESSURES...ONE IN
THE PACIFIC JUST WEST OF NORTHERN CHILE...AND ANOTHER IN THE
ATLANTIC EAST OF BRASIL. A MID LEVEL LOW IS EASTERN BRASIL WILL
ALSO DRIFT SOUTHWARD...POSSIBLY CENTERED NEAR GOIAS BY SATURDAY
MORNING.
IN THE LOWER LEVELS...THERE IS A TROUGH THAT WILL MOVE THROUGH
SOUTHERN SOUTH AMERICA TODAY...WITH A LOW PRESSURE MOVING IN
TONIGHT INTO THURSDAY. ANOTHER TROUGH WILL BE MOVING IN ON FRIDAY
AFTERNOON INTO SATURDAY MORNING. A LOW LEVEL LOW PRESSURE OVER
WEST CENTRAL ARGENTINA WILL BE CAUSING STRONG LOW LEVEL WINDS
ACROSS THE PATAGONIA FROM THE NORTH ON FRIDAY INTO SATURDAY. THIS
WILL INTERACT WITH A LOW PRESSURE OVER SOUTHERN SOUTH AMERICA AND
A COLD FRONT THAT IS MOVING NORTH EAST INTO NORTHEASTERN
PATAGONIA. THIS INTERACTION COMBINED WITH THE INFLOW OF MOISTURE
FROM THE NORTH AND THE STRONGER MID AND UPPER LEVEL WINDS MAY
CAUSE A SLIGHT OR MARGINAL RISK OF STRONG THUNDERSTORMS JUST
SOUTHWEST OF BUENOS AIRES.
ALAMO...(WPC)
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