373  
FXSA20 KWBC 011935  
PMDSA  
 
SOUTH AMERICA FORECAST DISCUSSION - INTERNATIONAL DESKS  
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD  
334 PM EDT MON JUL 01 2024  
 
GFS DATA AT FTPPRD.NCEP.NOAA.GOV/PUB/DATA/NCCF/COM/GFS/PROD/  
 
SOUTH AMERICAN DISCUSSION FOR 01 JUL 2024 AT 19 UTC: A MID-UPPER  
RIDGE IS BUILDING OVER THE EASTERN PACIFIC...WHICH IS LIMITING  
SYSTEMS IN THE WESTERLIES TO SOUTHERN AND SOUTH-CENTRAL CHILE OR  
TO LATITUDES SOUTH OF 36-38S. EMBEDDED IN THE WESTERLIES...SEVERAL  
SHORT WAVE PERTURBATIONS ARE PROPAGATING FROM WEST TO EAST. ON  
MONDAY...A SHORT WAVE TROUGH WILL INTERACT WITH AN ATMOSPHERIC  
RIVER OF 20-25MM TO FAVOR MODERATE PRECIPITATION BETWEEN SOUTHERN  
BIO BIO AND LOS LAGOS IN CHILE. EXPECT AMOUNTS OF 15-20MM/DAY AND  
MAXIMA OF 30-60MM...ACCOMPANIED BY A RISK OF SNOW IN ELEVATED  
TERRAIN. EAST OF THE ANDES...A MIX OF RAIN AND SNOW IS EXPECTED IN  
INTERIOR PORTIONS OF RIO NEGRO AND SOUTHERN NEUQUEN. ALTHOUGH PART  
OF THIS SNOW MIGHT BE WET...EXPECT ACCUMULATION OF 01-05CM AND  
MAXIMA OF 10CM. ON TUESDAY THIS DECREASES TO 05-10MM AND ISOLATED  
MAXIMA OF 15-20MM IN LOS LAGOS...ALTHOUGH ISOLATED MOUNTAIN SNOW  
IS POSSIBLE. THIS DECREASES THEREAFTER.  
 
IN THE SOUTHERN STREAM...A LARGE MID-UPPER LOS EXTENDS OVER THE  
BELLINGSHAUSEN SEA AND IS ACCOMPANIED BY AN UPPER JET ALONG ITS  
REAR END. THIS IS FORECAST TO YIELD TO THE AMPLIFICATION OF THE  
TROUGH AS IT MOVES EASTWARD DURING THE NEXT FEW DAYS. THE TROUGH  
IS FORECAST TO CROSS THE SOUTHERN CONE ON TUESDAY/EARLY  
WEDNESDAY...YIELDING TO AN EXTENSIVE PERIOD WITH SOUTHERLY FLOW  
THROUGH THE WEST OF THE WORK WEEK. THIS WILL FAVOR ANOTHER ROUND  
OF LOW TEMPERATURES AND PERIODS OF SNOWFALL IN AREAS SOUTH OF 40S.  
ON MONDAY...A SURFACE FRONT IS FORECAST TO ARRIVE IN THE SOUTHERN  
CONE IN THE EFENING ACCOMPANIED BY A TIGHT BELT OF WESTERLIES.  
THIS WILL FAVOR SNOFALL AMOUNTS OF 01-05CM/DAY AND MAXIMA OF 15MM  
IN WESTERN SLOPES AND ELEVATED TERRAIN OF NORTHERN MAGALLANES IN  
CHILE. ON TUESDAY...A SECOND FRONT IS FORECAST TO ARRIVE FROM THE  
SOUTHWEST ACCOMPANIED BY 35-50KT BOUNDARY LAYER WINDS. THIS WILL  
LIKELY FAVOR SNOWFALL AMOUNTS OF 05-10CM/DAY AND ISOLATED MAXIMA  
OF 15-25CM IN NORTHERN MAGALLANES/SOUTHERN AYSEN AND PORTIONS OF  
FAR WESTERN SANTA CRUZ IN ARGENTINA. ON WEDNESDAY...COLD AIR IS  
FORECAST TO EXTEND NORTH INTO LOS LAGOS...WHERE MODELS ARE  
SUGGESTING THE 5280 1000-500 HPA THICKNESS CONTOUR REACHING PUERTO  
MONTT AND BARILOCHE. THIS WILL FAVOR PERIODS WITH MIXED  
PRECIPITATION IN THESE REGIONS WITH LIQUID ACCUMULATION OF  
01-05MM/DAY AND MAXIMA OF 10MM. SOUTH-SOUTHWESTERLY FLOW IN AREAS  
TO THE SOUTH WILL LIKELY FAVOR 05-10CM/DAY AND ISOLATED MAXIMA OF  
15-25CM FROM WESTERN MAGALLANES INTO SOUTHERN AYSEN...WHILE  
LIGHTER SNOW SHOWERS PERSTER THE REST OF TIERRA DEL FUEGO AND  
SOUTHERN PATAGONIA.  
 
A SURFACE FRONT IS WEAKENING IN THE COAST OF ESPIRITO  
SANTO-BRASIL. GIVEN 35-40MM PRECIPITABLE WATER AMOUNTS AND ONSHORE  
FLOW THROUGH EARLY TUESDAY...EXPECT AMOUNTS OF 10-15MM/DAY AND  
MAXIMA OF 20-35MM ALTHOUGH VERY ISOLATED HIGHER AMOUNTS ARE  
POSSIBLE. ACCUMULATIONS DECREASE THEREAFTER.  
 
QUIET CONDITIONS ARE EXPECTED IN TROPICAL PORTIONS OF SOUTH  
AMERICA. THE LARGEST ACCUMULATIONS ARE LIKELY TO CLUSTER IN AREAS  
TO THE NORTH OF THE EQUATOR...PARTIALLY ASSOCIATED WITH TROPICAL  
WAVES ASSOCAITED WITH THE PERTUBATIONS IN THE CARIBBEAN/TROPICAL  
NORTH ATLANTIC. STILL...MAXIMA IN THUNDERSTORMS THAT FORM IN AREAS  
SOUTH OF THE EQUATOR IS LIKELY TO LIMIT TO 15-25MM/DAY.  
 
GALVEZ..(WPC)  
PALAVECINO (SMN-ARGENTINA)  
SARABIA (DMC-CHILE)  
 
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