004
FXSA20 KWBC 071920
PMDSA
SOUTH AMERICA FORECAST DISCUSSION - INTERNATIONAL DESKS
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
219 PM EST THU NOV 07 2024
GFS DATA AT FTPPRD.NCEP.NOAA.GOV/PUB/DATA/NCCF/COM/GFS/PROD/
SOUTH AMERICAN FORECAST BULLETIN FOR 07 NOV 2024 AT 1930 UTC:
ON THURSDAY...THE NORTH-CENTRAL PORTION OF THE CONTINENT IS SEEING
THE DEVELOPMENT OF THE SOUTH ATLANTIC CONVERGENCE ZONE (SACZ) WITH
THE ENTRANCE OF AN UPPER LEVEL TROUGH OVER CENTRAL
BOLIVIA...PARAGUAY...AND SOUTH BRASIL. TO THE WEST...A POTENT
UPPER RIDGE EXTENDS OVER PERU...EXTENDING OVER CENTRALÂBRASIL.
THEÂUPPER TROUGH IS ACCOMPANIED BY A FRONTAL SYSTEM THAT IS
EXPECTED OVER RIO GRANDE DO SUL AND SANTA CATARINA BY THURSDAY
EVENING. THE SYNOPTIC CONDITIONS WILL BE ENHANCED BY THE PRESENCE
OF INCREASED AMOUNTS OF PRECIPITABLE WATER IN THE REGION. IN
REGIONS OF PARAGUAY AND SOUTH BRASIL...EXPECT A SLIGHT RISK OF
SEVERE WEATHER WITH THE PASSING OF SHORT WAVE TROUGHS IN THE MID
TO UPPER LEVELS...ENHANCING LIFT AND THE DIVERGENT CONDITIONS FOR
DEEP CONVECTION. ON FRIDAY...THE UPPER TROUGH CONTINUES
PROGRESSING TO THE EAST AND NORTH...ENTERING SECTORS OF CENTRAL
BOLIVIA...MATO GROSSO DO SUL AND EXTENDING TO SAOÂPAULO. THE
POSITIONING OF THE UPPER TROUGH ENHANCES THE PRESENCE OF THE SACZ
FROM RIO DE JANEIRO/ESPIRITOÂSANTO ALONG SOUTH CENTRAL
BRASIL...EXTENDING THROUGH NORTH BOLIVIA/RONDONIA...AND ENTERING
ACRE AND SOUTH-CENTRAL PERU. INCREASED AREAS OF MOISTURE
CONVERGENCE ARE EXPECTED IN AMAZONAS/PERU AND IN SOUTH EAST
PORTIONS OF BRASIL...WHERE THE HEAVIEST PRECIPITATION IS
EXPECTED. AS THE TROUGH CONTINUES MOVING EASTWARD THE THREAT FOR
SEVERE WEATHER DIMINISHES AS THE FAVORABLE REGIONS OF MOST
DIVERGENCE IS EXPECTED OVER THE OCEAN BY FRIDAY EVENING. BY
SATURDAY EVENING...THE UPPER TROUGH IS EXPECTED OVER SAO PAULO AND
MATO GROSSO DO SUL...EXTENDING INTO SOUTH MINAS GERAIS/RIO DE
JANEIRO. THE SACZ IS POSITIONED OVER ESPIRITO SANTO/MINAS
GERAIS...AND EXTENDS INTO CENTRAL BRASIL AND SOUTH-CENTRAL PERU.
THE WESTERN PORTION OF THE SACZ COULD BEGIN WEAKENING AS THE
BOLIVIAN HIGH IS EXPECTED TO MEANDER INTO BOLIVIA/NORTH CHILE AND
EXTEND OVER MOST OF PERU AND AMAZONAS-BRASIL. ELEVATED AMOUNTS OF
PRECIPITABLE WATER ARE EXPECTED TO CONTINUE AND AS SUCH HEAVY
PRECIPITATION IS POSSIBLE THROUGHOUT THE AFOREMENTIONED REGIONS.
ON THURSDAY...EXPECT MAXIMA OF 35-70MM FROM MATO GROSSO TOWARDS TO
SOUTH INTO SAO PAULO/PARANA...AS WELL AS...IN NORTH BOLIVIA AND
SOUTH PERU. MAXIMA OF 30-60MM ARE EXPECTED IN CENTRAL PERU INTO
WEST AMAZONAS/ACRE-BRASIL...AND FROM PARA TO TOCANTINS-BRASIL.
WHILE MAXIMA OF 25-50MM ARE EXPECTED IN SOUTH BOLIVIA INTO NORTH
PARAGUAY AND EXTREME NORTHWEST ARGENTINA. SIMILAR AMOUNTS ARE
EXPECTED IN SANTA CATARINA AND RIO GRANDE DO SUL WITH A SLIGHT
RISK OF SEVERE WEATHER. ON FRIDAY...AS THE SACZ AND UPPER TROUGH
PROPAGATE TO THE NORTH AND EAST...MAXIMA OF 50-100MM ARE EXPECTED
IN SOUTH ESPIRITO SANTO...RIO DE JANEIRO...MINAS GERAIS...AND EAST
SAO PAULO. EXPECT MAXIMA BETWEEN 30-70MM FROM NORTH BOLIVIA AND
WEST BRASIL INTO REGIONS OF CENTRAL BRASIL. MAXIMA OF 40-80MM ARE
EXPECTED IN CENTRAL PERU AND PORTIONS OF WEST AMAZONAS-BRASIL. ON
SATURDAY...EXPECT A GENERALIZED MAXIMA OF 25-50MM FROM NORTH PERU
INTO PORTION OF NORTH AND CENTRAL BRASIL. A SMALLER REGION IN
ESPIRITO SANTO AND EAST MINAS GERAIS CAN EXPECT MAXIMA OF
50-100MM. WHILE REGIONS IN SOUTH PERU AND WEST MINAS GERAIS AND
SAO PAULO CAN EXPECT MAXIMA OF 30-60MM. ALL THE AFOREMENTIONED
REGIONS OVER THE NEXT THREE DAYS CAN EXPECT HIGHER AMOUNTS OF
PRECIPITATION AT A LOCAL LEVEL.
IN THE SOUTHERN PORTION OF THE CONTINENT...AN INCREASINGLY DRIER
TREND IS EXPECTED OVER THE NEXT SEVERAL DAYS DUE TO THE LIMITED
MOISTURE EXPECTED FROM THE PRESENCE OF THE SACZ FURTHER NORTH. THE
SACZ IS EXPECTED TO LIMIT THE AMOUNT OF TROPICAL MOISTURE THAT
REACHES THE REGION AND LIMITING THE AMOUNT OF AVAILABLE MOISTURE
FOR HEAVY PRECIPITATION. THE PRESENCE OF SHORT WAVE TROUGHS
ENTERING ARGENTINA MAY PROVIDE THE DYNAMIC FOR DEEP
CONVECTION...HOWEVER. THE EXCEPTION IS IN SOUTHERN CHILE WHERE
FRONTAL BOUNDARIES WITH MOISTURE ASSOCIATED WITH THEM WILL BE
MAKING THEIR WAY INTO THE ZONES SUR AND AUSTRAL OVER THE NEXT
SEVERAL DAYS.ÂON THURSDAY...SOUTH AYSEN AND MAGALLANES CAN EXPECT
MAXIMA OF 20-35MM...WHILE NORTH AYSEN AND LOS LAGOS IN CHILE CAN
EXPECT MAXIMA OF 15-20MM. BY FRIDAY...THE ENTRANCE OF AN UPPER
LEVEL SHORT WAVE TROUGH WILL FAVOR A RISK OF THUNDERSTORM ACTIVITY
IN AYSEN WITH A MAXIMA OF 15-30MM. HIGHER AMOUNTS OF 20-40MM ARE
EXPECTED IN NORTH AYSEN TO SOUTH BIO BIO...AS THE FRONTAL SYSTEM
ENTERS THE REGION. BY SATURDAY...THE PROGRESSIVE SHORT WAVE
TROUGHS IN THE MID TO UPPER LEVELS WILL CONTINUE INTO
ARGENTINA...WHERE IT WILL FAVOR A MODERATE RISK OF SEVERE WEATHER
FROM SOUTH BUENOS AIRES SOUTH SAN JUAN...WHILE A FRONTAL BOUNDARY
IS STATIONARY OVER THE REGION. EXPECT A MAXIMA OF 25-50MM LOCALLY.
SOUTHERN CHILE CAN EXPECT MAXIMA OF 20-35MM IN AYSEN...WHILE
MAGALLANES CAN EXPECT MAXIMA OF 15MM.
CASTELLANOS...(WPC)
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