SOUTH AMERICA FORECAST DISCUSSION - INTERNATIONAL DESKS
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
222 PM EDT FRI AUG 30 2024

GFS DATA AT FTPPRD.NCEP.NOAA.GOV/PUB/DATA/NCCF/COM/GFS/PROD/

SOUTH AMERICAN FORECAST BULLETIN FOR 30 AUG 2024 AT 1820 UTC:

OVER THE NEXT 3 DAYS...A FEW EVENTS CAN BE EXPECTED ACROSS
PORTIONS OF SOUTH AMERICA. ONE AREA IS OVER EASTERN ARGENTINA INTO
URUGUAY...WHERE MODERATE TO HEAVY RAIN CAN BE EXPECTED TODAY AND
SATURDAY...WITH A SLIGHT RISK OF SEVERE WEATHER OVER URUGUAY.
ACROSS SOUTHERN CHILE...AN ATMOSPHERIC RIVER WILL AFFECT AREAS
FROM BIO BIO SOUTH TO AYSEN...CAUSING AN INCREASE IN RAIN AND
SNOWFALL ACROSS THE AREA...ESPECIALLY ON SATURDAY AND SUNDAY.
THERE IS ALSO SOME SNOW AND RAIN MIX ACROSS BOLIVIA AND SOUTHERN
PERU THAT COULD BE OBSERVED AS A COLD MID LEVEL TROUGH EXTENDS
NORTH OVER THE AREA WITH ONSHORE FLOW.

A LOW LEVEL JET OVER SOUTH AMERICA JUST EAST OF A COLD FRONT WILL
INTERACT WITH A STATIONARY FRONT IN AND AROUND URUGUAY...CAUSING
POOLING OF LOW LEVEL MOISTURE OVER THE AREA. THIS AREA WILL
EVENTUALLY DEVELOP A LOW PRESSURE AND A WARM FRONT WILL DEVELOP
AND PUSH SOUTHEAST INTO THE ATLANTIC WATERS BY SUNDAY. FOR TODAY
AND SATURDAY...THERE WILL ALSO BE A MID AND UPPER LEVEL LOW
PRESSURE THAT WILL MOVE INTO ARGENTINA...POSITIONING OVER THE
COUNTRY BOUNDARY BETWEEN ARGENTINA AND URUGUAY BY SATURDAY
EVENING. THE COMBINATION OF THE DEVELOPING SFC LOW WITH THE MID
AND UPPER LEVEL LOW...WITH THE STRONG NORTHERLY WINDS AND
RELATIVELY DEEP MOISTURE...WILL CAUSE SIGNIFICANT AMOUNTS OF RAIN
TODAY INTO SATURDAY OVER THE AREA.
BASED ONT EH LATEST GUIDANCE...THIS PATTERN WILL CAUSE RAINFALL
WITH MAX VALUES NEAR 40-80MM OVER ARGENTINA AND URUGUAY...WHILE
LOWER AMOUNTS OF RAIN CAN BE EXPECTED OVER NORTHERN URUGUAY...WITH
MAX VALUES OF 20-40MM FORECAST FOR TODAY AND SATURDAY. THAT BEING
SAID...THE BEST INSTABILITY IS EXPECTED OVER URUGUAY...AND THUS
THERE IS A MODERATE RISK OF SEVERE WEATHER TODAY FOR PORTIONS OF
URUGUAY AND ADJACENT AREAS...BUT THE RISK DECREASES DURING THE
WEEKEND. BY SUNDAY INTO MONDAY...THE DEVELOPING LOW PRESSURE AND
ASSOCIATED FRONTS ARE FORECAST TO MOVE OFFSHORE INTO THE ATLANTIC.

SOUTH CENTRAL TO SOUTHERN CHILE IS EXPECTED TO HAVE AN EVENT WITH
AN ATMOSPHERIC RIVER OVER THE NEXT FEW DAYS. THE PRECIPITABLE
WATER IS EXPECTED TO INCREASE TO AS MUCH AS 25MM BY SATURDAY
EVENING...AND OVER 30MM BY SUNDAY EVENING. THE ATMOSPHERIC RIVER
IS EXPECTED TO GRADUALLY MOVE NORTH THROUGH THE WEEKEND...CAUSING
THE INCREASE IN PRECIPITABLE WATER TO MOVE NORTH WITH EACH DAY
THIS WEEKEND. THEREFORE...THE AREAS WITH SIGNIFICANT RAIN WILL BE
MAINLY OVER AYSEN ON SATURDAY...WITH UP TO 70MM OF RAIN WITH SNOW
IN THE HIGHER ELEVATIONS. ON SUNDAY...THE MOISTURE WILL BE HIGHER
FURTHER NORTH...AFFECTING AREAS IN AND AROUND BIO BIO TO LAGOS ON
SUNDAY...WITH MAX VALUES NEAR 25-50MM OF RAIN AND UP TO 30CM OF
SNOW.

THE AFOREMENTIONED MID LEVEL TROUGH THAT WILL EXTEND INTO BOLIVIA
AND SOUTHERN PERU WILL CAUSE INCREASE IN MOISTURE AND COLD TEMPS
OVER THE AREA ON SATURDAY AND SUNDAY. THIS COULD RESULT IN AREAS
OF RAIN AND SNOW SHOWERS OVER WESTERN BOLIVIA AND SOUTHERN PERU.
WITH ALL SNOW OVER THE HIGHEST ELEVATIONS AND A RAIN AND SNOW MIX
OVER THE VALLEYS...ALTHOUGH THE AMOUNTS ARE NOT EXPECTED TO BE TOO
SIGNIFICANT...WITH DAILY PRECIP MAX VALUES OF AROUND 15-20MM.


ALAMO...(WPC)
LOPEZ...(DMH PARAGUAY)
PALAVECINO...(SMN ARGENTINA)


NOTE...THE NEXT DISCUSSION WILL BE ON 3 SEPT 2024 DUE TO THE LABOR
DAY HOLIDAY.