467
FXSA20 KWBC 011918
PMDSA
SOUTH AMERICA FORECAST DISCUSSION - INTERNATIONAL DESKS
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
317 PM EDT THU AUG 01 2024
GFS DATA AT FTPPRD.NCEP.NOAA.GOV/PUB/DATA/NCCF/COM/GFS/PROD/
SOUTH AMERICAN FORECAST BULLETIN FOR 01 AUG 2024 AT 1915 UTC:
ON THURSDAY...THE UPPER LEVEL TROUGH IS JUST WEST OF CHILE...WHILE
A SHORT WAVE TROUGH EMBEDDED IN THE WIDE TROUGH IS EXPECTED TO
CROSS PRIOR INTO CHILE AND THE PATAGONIA IN ARGENTINA IN THE
EARLIER HOURS OF THURSDAY. IN THE LOWER LEVELS...A WARM FRONTAL
BOUNDARY CROSSES THE ANDES AND IS EXPECTED OVER THE PATAGONIA BY
THURSDAY EVENING...WHILE THE COLD FRONT EXTENDS FROM THE
PATAGONIA...ALONG THE ANDES MOUNTAINS...AND EXITS INTO THE PACIFIC
OCEAN BY COQUIMBO. WITH THE ASSISTANCE OF THE MID TO UPPER LEVEL
TROUGH AND THE INCREASED MOISTURE ASSOCIATED WITH THE ATMOSPHERIC
RIVER AND FRONTAL SYSTEM...EXPECT HEAVY PRECIPITATION FROM ATACAMA
TO ARAUCANIA. THE EXPECTED MAXIMA FOR THIS REGION IS
40-80MM...WITH LOCALIZED HIGHER AMOUNTS POSSIBLE. THE RISK OF
THUNDERSTORMS IS ALSO EXPECTED DUE TO THE COLDER INTRUSION BEHIND
THE FRONT. TO THE SOUTH...FROM SOUTH LOS RIOS TO NORTH AYSEN...AND
TO THE NORTH...IN SOUTH ANTOFAGASTA TO NORTH ATACAMA EXPECT MAXIMA
OF 20-40MM. THE SOUTHERN REGION IN LOS REGION TO NORTH AYSEN CAN
EXPECT A RISK OF THUNDERSTORMS.
ON FRIDAY...THE MID TO UPPER LEVEL TROUGH CONTINUES PROPAGATING
EAST AND ENTERS THE CONTINENT BY THE EVENING HOURS. THE UPPER JET
IS SITUATED OVER THE NORTHERN PORTION OF CHILE AND WILL ASSIST
WITH HEAVY PRECIPITATIONS FOR FRIDAY IN THE REGION. TO THE SOUTH
IN CHILE...MOISTURE FROM FRONTAL BOUNDARIES WILL CONTINUE TO
CONVERGE ALONG CHILE AND THEY ARE EXPECTED TO SEE MODERATE TO
HEAVY PRECIPITATION. TO THE EAST...THE PREVIOUS COLD FRONTAL
BOUNDARY IS EXPECTED OVER THE CENTRAL CHILE AND EXTENDS INTO
BUENOS AIRES...AND EXITS INTO THE ATLANTIC OCEAN. THIS WILL MEET
UP WITH THE WARMER AND MORE HUMID AIR THAT IS BEING ADVECTED FROM
THE NORTH WITH THE ASSISTANCE OF THE SALLJ AND THE LOW LEVEL JETS
THAT HAVE DEVELOPED OVER THE CONTINENT AS THE MID TO UPPER TROUGH
HAS CROSSED INTO THE REGION. THIS DIFFERENCE IN AIR MASSES...WITH
INCREASE THE INSTABILITY OVER ARGENTINA...AND WILL EXTEND FURTHER
EAST AND NORTH AS THE COLD FRONT CONTINUES PROPAGATING TO THE
NORTH AND EAST. THE UPPER JET WILL PERSIST OVER THE REGION AND
PROVIDE VENTILATION FOR THE DEVELOPMENT OF SEVERE WEATHER. MODEL
GUIDANCE HAS SHIFTED FOR FRIDAY'S FORECAST TO A MODERATELY SEVERE
RISK. IN THE MID LEVELS...A SERIES OF SHORT WAVE TROUGHS WERE
EXPECTED TO MOVE OVER THE REGION...INCREASING THE CHANCE FOR MORE
SEVERE STORMS. HOWEVER...TODAY THE MODELS ARE NOT PRESENTING SHORT
WAVE TROUGHS AS PROMINENT OVER THE REGION. IN TERMS OF
PRECIPITATION...FROM CENTRAL COQUIMBO TO SANTIAGO
METROPOLITAN...EXPECT MAXIMA OF 25-50MM...WITH RISK OF
THUNDERSTORMS. IN THE NORTH...FROM SOUTH ANTOFAGASTA TO
COQUIMBO...AND FROM O'HIGGINS TO LOS LAGOS...EXPECT MAXIMA OF
20-40MM. IN SOUTH AYSEN TO CENTRAL MAGALLANES...EXPECT MAXIMA OF
15-25MM. IN ARGENTINA...MAXIMA OF 20-40MM WITH A MODERATE RISK OF
SEVERE WEATHER...ARE EXPECTED FROM SOUTH SANTA FE AND ENTRE
RIOS...TO BUENOS AIRES.
ON SATURDAY...OVER IN CHILE...ANOTHER FRONTAL SYSTEM AND
ATMOSPHERIC RIVER IS EXPECTED TO ARRIVE TO CHILE AND INCREASE THE
AMOUNT OF AVAILABLE MOISTURE FROM NORTH AYSEN TO LOS RIOS. THE
REGION CAN EXPECT AMOUNTS OF 20-40MM WITH MOUNTAIN SNOW IN THE
HIGHER ELEVATIONS. A SHORT WAVE TROUGH IN THE MID LEVELS WILL
ASSIST IN THE DEVELOPMENT OF THE PRECIPITATION IN THE REGION ON
SATURDAY. OVER THE CENTRAL PORTION OF THE CONTINENT...THE COLD
FRONT ADVANCES INTO SOUTHERN BOLIVIA...PARAGUAY...AND INTO
SOUTHERN BRASIL. THE INSTABILITY IN THE REGION DUE TO THE LOW
LEVEL JETS AND THE TRANSPORT OF WARMER AIR AND MOISTURE INTO THE
REGION WILL PERSIST. FROM SOUTHERN PARAGUAY AND SOUTH
FORMOSA-ARGENTINA...TO RIO GRANDE DO SUL EXPECT MAXIMA OF 20-35MM
WITH A SLIGHT RISK OF SEVERE WEATHER. SOUTHERN URUGUAY CAN EXPECT
A MAXIMA OF 15-20MM.
THE REST OF THE CONTINENT CONTINUES TO SEE DRY CONDITIONS AND MOST
OF THE PRECIPITATION OVER THE TROPICAL REGION OF THE CONTINENT IS
EXPECTED FURTHER NORTH. MAXIMA IN THE NORTH ARE EXPECTED TO REMAIN
BELOW 25MM AND ARE EXPECTED TO BE ISOLATED.
ACOSTA...(WPC)
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