060
FXSA20 KWBC 202008
PMDSA
SOUTH AMERICA FORECAST DISCUSSION - INTERNATIONAL DESKS
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
407 PM EDT TUE AUG 20 2024
GFS DATA AT FTPPRD.NCEP.NOAA.GOV/PUB/DATA/NCCF/COM/GFS/PROD/
SOUTH AMERICAN FORECAST BULLETIN FOR 20 AUG 2024 AT 19 UTC:
A LARGE UPPER TROUGH EXTENDS OVER THE EASTERN PACIFIC...CENTERING
ON A LOW NEAR 40S 79W AND EXTENDING AN AXIS NORTH INTO 18S 90W.
THIS TROUGH IS MOVING VERY SLOWLY...AND IS FORECAST TO CROSS THE
ANDES ON WEDNESDAY MORNING. SYSTEM IS FORECAST TO FULLY EXIT INTO
THE ATLANTIC BY FRIDAY IN A SLOW-TO-PROGRESS EVOLUTION. THE MAIN
TWO IMPACTS OF THIS TROUGH WILL CONTINUE TO BE SNOWFALL IN THE
ANDES AND EASTERN SLOPES IN CENTRAL AND SOUTH-CENTRAL
ARGENTINA...AND SEVERE CONVECTION AND LOCALLY HEAVY RAINFALL AS IT
INTERACTS WITH A MOIST AIR MASS BUILDING IN NORTHEAST ARGENTINA
AND URUGUAY. ON TUESDAY...EXPECT A MIX OF RAIN AND SNOW IN LA
PAMPA/SAN LUIS WITH LIQUID ACCUMULATION OF 05-10MM/DAY AND
ISOLATED MAXIMA OF 15-20MM. IN NORTHEAST ARGENTINA AND
URUGUAY...ISENTROPIC LIFT OF A MOIST 35-45MM PRECIPITABLE WATER
AIR MASS WILL FAVOR DEEP CONVECTION AND POTENTIAL MAXIMA OF
30-60MM/DAY. NOTE THAT A MODERATE RISK FOR SEVERITY EXISTS. ON
WEDNESDAY...EXPECT THE HEAVIEST PRECIPITATION TO CLUSTER IN
NORTHEAST ARGENTINA...URUGUAY AND FAR SOUTHERN BRASIL...WHERE
EXPECT MAXIMA OF 40-80MM AND A MODERATE RISK FOR SEVERE WEATHER.
ON THURSDAY...EXPECT MAXIMA OF 50-100MM/DAY AND A SLIGHT RISK OF
SEVERE CONVECTION IN CENTRAL AND SOUTHEAST PARAGUAY AND IN
MISIONES. IN NORTHERN RIO GRANDE DO SUL EXPECT MAXIMA OF 30-60MM.
AS THE UPPER TROUGH CROSSES THE CORDILLERA...EXPECT PERIODS OF
SCATTERED SNOWFALL FROM CENTRAL CHILE INTO CENTRAL
PATAGONIA...WHILE FAIR WEATHER FOCUSES IN SOUTHERN PATAGONIA. ON
TUESDAY EXPECT LIGHT SHOWERS IN COASTAL CENTRAL CHILE WITH A
CHANCE FOR SHORT PERIODS OF RAIN/SNOW MIX SOUTH OF TALCA. IN THE
CORDILLERA...EXPECT MAXIMUM SNOW ACCUMULATION OF 15-20CM FROM
CENTRAL CHILE INTO THE ATACAMA REGION. ON WEDNESDAY...THE PASSAGE
OF THE UPPER LOW WILL FAVOR SNOWFALL IN CENTRAL PATAGONIA WITH
FORECAST AMOUNTS OF 01-05CM/DAY. IN CENTRAL CHILE...THE OCCLUDED
LOW WILL FAVOR 05-10MM/DAY AND MAXIMA OF 15MM...WHILE IN THE
CORDILLERA EXPECT SNOWFALL MAXIMA OF 15-30CM. ON THUSDAY...EXPECT
AMOUNTS OF 05-10MM/DAY AND VERY ISOLATED MAXIMA OF 15-20MM IN
CHILE FROM O'HIGGINS TO LOS LAGOS.
NORTH OVER THE CONTINENT...THE DRY SEASON CONTINUES FAVORING
WIDESPREAD FAIR WEATHER CONDITIONS. A TROUGH IN THE TRADES IS
FORECAST TO ENTER NORTHEAST BRASIL ON TUESDAY AND WEDNESDAY
ACCOMPANIED BY A MOIST PLUME. LIMITED AMOUNTS OF AVAILABLE
MOISTURE AND AN ENHANCED TRADE WIND CAP WILL LIMIT POTENTIAL
ACCUMULATIONS WITH THIS SYSTEM.
GALVEZ...(WPC)
PALAVECINO...(SMN ARGENTINA)
LOPEZ...(DMH PARAGUAY)
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