615
FXSA20 KWBC 091920
PMDSA
SOUTH AMERICA FORECAST DISCUSSION - INTERNATIONAL DESKS
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
320 PM EDT FRI AUG 09 2024
GFS DATA AT FTPPRD.NCEP.NOAA.GOV/PUB/DATA/NCCF/COM/GFS/PROD/
SOUTH AMERICAN FORECAST BULLETIN FOR 08 AUG 2024 AT 1930 UTC:
ON FRIDAY...THE MID TO UPPER LEVEL TROUGH EXTENDS INTO THE
CENTRAL-SOUTHERN PORTION OF BRASIL...WHILE AN UPPER LEVEL RIDGE IS
PRESENT OVER THE NORTHERN PORTION OF THE CONTINENT...BLOCKING THE
ENTRANCE OF THE TROUGH FURTHER NORTH. TO THE SOUTH...ANOTHER MID
TO UPPER LEVEL TROUGH IS ENTERING SOUTH-CENTRAL CHILE...AND IT IS
FOLLOWED BY A JET STREAK THAT WILL ENHANCE THE TROUGH OVER THE
NEXT FEW DAYS. THE TROUGH IN THE SOUTHERN PORTION OF THE CONTINENT
IS EXPECTED TO PROGRESS QUICKLY AND LEAVE THE CONTINENT BY MONDAY.
IN THE LOWER LEVELS...A COLD FRONT IS PROGRESSING TO THE NORTH AND
IT IS EXPECTED TO BE SITUATED OVER NORTH ACRE-BRASIL...EXTEND INTO
THE CENTRAL PORTIONS OF THE COUNTRY...AND EXIT THROUGH RIO DE
JANEIRO BY FRIDAY EVENING. A FRIAJE EVENT IS EXPECTED OVER THE
AFOREMENTIONED REGIONS AS COLDER AIR ENTERS BEHIND THE FRONT.
HOWEVER...DUE TO THE UPPER LEVEL RIDGE IT ENCOUNTERS...THE FRONT
BEGINS TO LOSE DEFINITION BY SATURDAY MORNING. IN ADDITION...IN
THE NORTHERN TROPICAL PORTION OF THE CONTINENT...THE PASSING OF
TROPICAL WAVES AND TROUGHS ARE FAVORING HIGHER AMOUNTS OF
PRECIPITABLE WATER IN THE REGION...WHICH WILL CONVERGE ALONG THE
MOUNTAIN RANGE IN COLOMBIA. IN TERMS OF PRECIPITATION...EXPECT
MAXIMA OF 30-60MM FROM SOUTHERN COLOMBIA...TO SOUTHERN VENEZUELA.
DUE TO THE CONVERGENCE OF MOISTURE IN NORTHER PERU DUE TO
SOUTHERLY FLOW...EXPECT MAXIMA OF 20-35MM. INTO SOUTHERN
BRASIL...EXPECT MAXIMA OF 20-40MM IN RIO DE JANEIRO AND EAST SAO
PAULO...AND SOUTHERN MINAS GERAIS DUE TO THE POST FRONTAL MOISTURE
EXPECTED AFTER THE FRONTAL PASSAGE. SIMILARLY...FROM MATO GROSSO
DO SUL INTO PARANA AND NORTH SAO PAULO...EXPECT MAXIMA OF 15-20MM.
IN SOUTHERN CHILE...THE ENTRANCE OF A FRONTAL SYSTEM WILL FAVOR
MAXIMA OF 15-30MM FROM THE ZONA SUR TO NORTHERN ZONA
AUSTRAL...EXPECT MAXIMA OF 15-30MM.
ON SATURDAY...MOISTURE CONTINUES TO CONVERGE OVER NORTHERN
PERU...SOUTHERN COLOMBIA...AND SOUTHERN VENEZUELA...WITH THE
MOVEMENT OF A TROPICAL WAVE AND OTHER TROUGHS PROPAGATING IN THE
TRADE WINDS. EXPECT MAXIMA OF 20-45MM IN WEST-SOUTH
COLOMBIA...WITH ONSHORE FLOW FAVORING CONVERGENCE ALONG THE
MOUNTAIN RANGE. LESSER AMOUNTS OF 20-35MM ARE EXPECTED IN NORTHERN
PERU AND EAST ECUADOR AS MOISTURE CONVERGES IN THIS REGION...BUT A
DECREASE IS EXPECTED WITH THE DECREASE IN AVAILABLE MOISTURE IN
THE REGION. TO THE EAST...THE FRONTAL BOUNDARY HAS DISSIPATED OVER
CENTRAL PORTIONS OF BRASIL...WITH A DYING COLD FRONT EXPECTED IN
SOUTHERN BAHIA AND NORTHERN ESPIRITO SANTO. A DECREASE IN
AVAILABLE MOISTURE WILL FAVOR GENERALIZED MAXIMA OF 15-25MM FROM
RIO DE JANEIRO TO SOUTH OF BAHIA. TO THE SOUTH...SOUTHERN CHILE
WILL SEE THE ENTRANCE OF A RIDGE PATTERN SEEN FROM THE UPPER
LEVELS IN THE ATMOSPHERE...AND REFLECTED IN THE LOW LEVELS AS
WELL. WHILE THE MID TO UPPER LEVEL TROUGH BEGINS TO EXIT THE
REGION. A DECREASE IN PRECIPITATION IS EXPECTED...WITH MAXIMA OF
15MM FROM THE ZONA SUR TO CENTRAL ZONA AUSTRAL...WITH MOUNTAIN
SNOW IN THE HIGHER ELEVATIONS. ALONG THE EASTERN PORTIONS FROM
ARGENTINA...INTO URUGUAY...EXPECT COLDER AIR TO ENTER...BUT
MINIMAL AMOUNTS OF PRECIPITATION DUE TO LOW AVAILABLE MOISTURE.
ON SUNDAY...THE NORTHER PORTION OF THE CONTINENT CONTINUES TO SEE
THE PASSING OF THE TROUGHS ALONG THE TRADES...WHICH WILL FAVOR
PRECIPITATION IN SOUTHERN VENEZUELA INTO RORAIMA...AND
AMAZONAS-BRASIL. EXPECT MAXIMA OF 20-45MM. TO THE WEST...ONSHORE
FLOW IN SOUTHWEST COLOMBIA WILL FAVOR MAXIMA OF 20-35MM. A
DECREASE IN AVAILABLE MOISTURE IS SEEN INTO PERU...AND
BOLIVIA...AS SUCH...EXPECT A DECREASE IN PRECIPITATION WITH MAXIMA
OF 15-20MM. THIS IS DUE TO THE ENHANCE HIGH PRESSURE OVER THE
CONTINENT...FOLLOWING THE PASSAGE OF THE FRONTAL BOUNDARY ON
FRIDAY. THE REMAINING PORTION OF THE FRONTAL BOUNDARY IS EXPECTED
OFFSHORE BAHIA-BRASIL...WHERE THE REMAINING MOISTURE IS EXPECTED
TO FAVOR MAXIMA OF 15MM. IN SOUTHERN CHILE...AN ATMOSPHERIC RIVER
ACCOMPANIED BY THE ENTRANCE OF AN UPPER LEVEL JET ARRIVES IN THE
ZONA AUSTRAL IN CHILE. HOWEVER...THE AVAILABLE MOISTURE ASSOCIATED
WITH THIS ATMOSPHERIC RIVER IS EXPECTED TO REMAIN LOW...AND THUS
THE MOISTURE TRANSPORT EXPECTED WILL NOT BRING HEAVY
PRECIPITATION. MAXIMA EXPECTED FROM SOUTHERN ZONA SUR TO THE ZONA
AUSTRAL...EXPECT MAXIMA OF 15-25MM.
ACOSTA...(WPC)
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