507
FXSA20 KWBC 151757
PMDSA
SOUTH AMERICA FORECAST DISCUSSION - INTERNATIONAL DESKS
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
1257 PM EST FRI NOV 15 2024
GFS DATA AT FTPPRD.NCEP.NOAA.GOV/PUB/DATA/NCCF/COM/GFS/PROD/
SOUTH AMERICAN FORECAST BULLETIN FOR 15 NOV 2024 AT 1800 UTC:
ON FRIDAY...THE BOLIVIAN HIGH BEGINS AS A DISORGANIZED HIGH
PRESSURE SYSTEM IN THE UPPER LEVELS...EXTENDING OVER MOST OF THE
NORTHERN REGION OF SOUTH AMERICA. ALTHOUGH WEAK...THE BLOCKING
PATTERN FROM THE HIGH PRESSURE SYSTEM IS PREVENTING TROUGHS TO
REACH FURTHER NORTH. AN UPPER TROUGH EXTENDS OVER NORTH
ARGENTINA...INTO PARAGUAY...REACHING SOUTH BOLIVIA...AND STAYING
SOUTH OF 15S IN THE EARLY HOURS ON FRIDAY. IN THE LOWER
LEVELS...CONVERGING FLOW WITH MUCH AVAILABLE MOISTURE IS
TRIGGERING CONVECTION OVER MOST OF CENTRAL BRASIL...EXTENDING
NORTHWARD INTO SOUTH PARA AND EAST AMAZONAS. AS THE DAY PROGRESSES
ON FRIDAY...THESE REGIONS WILL EXPAND FURTHER NORTH AND
WEST...WHERE EXPECT MAXIMA OF 35-70MM IN PARA/EAST AMAZONAS...MATO
GROSSO...TOCANTINS...AND NORTH GOIAS. IN THE SOUTHERN REGIONS OF
SAO PAULO AND RIO DE JANEIRO...THE PRESENCE OF REMNANTS OF A
FRONTAL BOUNDARY REMAIN. WITH THE PRESENCE OF AN UPPER TROUGH AND
JET FAVORING VENTILATION FOR DEEP CONVECTION...EXPECT MAXIMA OF
30-60MM IN SOUTH SAO PAULO AND SOUTHWEST RIO DE JANEIRO. ELSEWHERE
IN THE REGION...EXPECT SCATTERED AMOUNTS UNDER 40MM. ON
SATURDAY...THE BOLIVIAN HIGH IN THE BOLIVIAN HIGH BEGINS TO
STRENGTHEN OVER NORTHERN SOUTH AMERICA AND AS IT INTERACTS WITH
THE TROUGH TO THE SOUTH...BEGINS TO ENHANCE THE JET OVER SOUTH
BRASIL. TO THE WEST INTO NORTH ARGENTINA/PARAGUAY...AN ENHANCED
JET WILL FAVOR VENTILATION IN THE REGION OF PARAGUAY AND NORTH
ARGENTINA. TO THE NORTH...THE MOISTURE CONVERGENCE PROPAGATES TO
THE WEST INTO AMAZONAS-BRASIL AND PERU/NORTH BOLIVIA.
ADDITIONALLY...MOISTURE BEGINS TO BE ADVECTED TO THE SOUTH INTO
BOLIVIA AND NORTH PARAGUAY/ARGENTINA. THIS INCREASE IN MOISTURE
CONVERGING ALONG THE MOUNTAIN RANGE...AND FEELING THE EFFECTS OF
THE UPPER RIDGE ENHANCEMENT AND JET ENHANCEMENT WILL FAVOR THE
VENTILATION FOR CONVECTION. EXPECT MAXIMA OF 20-35MM IN SOUTH
BOLIVIA INTO NORTH ARGENTINA. MAXIMA OF 20-45MM ARE EXPECTED IN
CENTRAL PERU...AND MAXIMA OF 20-35MM IN EAST AND NORTH PERU.
SCATTERED MAXIMA OF 30-60MM...WITH ISOLATED HIGHER AMOUNTS
POSSIBLE ARE EXPECTED IN NORTHWEST BRASIL INTO RONDONIA. CENTRAL
BRASIL CAN EXPECT MAXIMA OF 20-45MM. WITH THE TROUGHS IN THE LOWER
LEVELS IN SOUTH MINAS GERAIS...SAO PAULO...AND WEST RIO DE JANEIRO
FEELING THE ENHANCEMENT OF THE DIVERGENT UPPER TROUGH WILL FAVOR
MAXIMA OF 30-60MM WITH A MARGINAL RISK OF SEVERE WEATHER. ON
SUNDAY...THE UPPER RIDGE...AND JET WILL CONTINUE TO STRENGTHEN
OVER THE CENTRAL REGION OF SOUTH AMERICA...WHILE A FRONTAL
BOUNDARY ENTERS THE BORDER BETWEEN ARGENTINA/BOLIVIA. THESE
INTERACTION WILL FAVOR DEEP CONVECTION AND HEAVY PRECIPITATION IN
THE REGION. TARIJA-BOLIVIA/NORTH SALTA PROVINCE-ARGENTINA CAN
EXPECT MAXIMA OF 35-70MM WITH THE PRESENCE OF THE COLD FRONT. FROM
NORTHWEST PARAGUAY TO NORTH ARGENTINA EXPECT MAXIMA OF 25-50MM
WITH A MARGINAL RISK OF SEVERE WEATHER. FROM ENTRE
RIOS-ARGENTINA...THROUGH URUGUAY...AND SOUTH RIO GRANDE DO
SUL...EXPECT MAXIMA OF 20-35MM WITH A MARGINAL RISK OF SEVERE
WEATHER AS THE COLD FRONT IS EXPECTED TO EXTEND INTO THE REGION
ENHANCED BY DIFFLUENCE FROM THE EXIT REGION OF THE UPPER JET. THE
UPPER LEVEL TROUGH IN SAO PAULO/RIO DE JANEIRO REMAINS MOSTLY OVER
THE ATLANTIC OCEAN...YET THE BASE OF THE TROUGH EXTENDS INTO THE
REGION. THIS WILL FAVOR PRECIPITATION AS THE TROUGHS IN THE LOWER
LEVEL CONTINUE TO TRIGGER CONVECTION IN THE REGION. EXPECT MAXIMA
OF 25-50MM WITH A MARGINAL RISK OF SEVERE WEATHER. ELSEWHERE IN
CENTRAL AND NORTH BRASIL...EXPECT SCATTERED MAXIMA OF 20-35MM WITH
A POTENTIAL FOR HIGHER AMOUNTS LOCALLY.
IN THE SOUTHERN CONE OF SOUTH AMERICA IS SEEING UPPER JET AND A
TROUGH IN THE UPPER LEVELS ENTER THE REGION WITH SOME DIVERGENCE
ALOFT ON FRIDAY. DUE TO THE LOW AMOUNT OF AVAILABLE MOISTURE IN
THE REGION...PRECIPITATION MAXIMA ARE EXPECTED TO REMAIN BELOW
25MM FROM LOS LAGOS TO MAGALLANES-CHILE. TO THE NORTH...A COLD
FRONT EXTENDS FROM CENTRAL CHILE...THROUGH CENTRAL
ARGENTINA...INTO BUENOS AIRES. BUENOS AIRES CAN EXPECT MAXIMA OF
15-25MM WITH THE PASSING OF THE FRONT. ON SATURDAY...A NEW FRONTAL
BOUNDARY ENTERS SOUTHERN CHILE WITH PRECIPITABLE WATER VALUES
BETWEEN 20-25MM. THE PERPENDICULAR DIRECTION OF THE FLOW WILL
FAVOR STEADY MOIST ONSHORE IN NORTH MAGALLANES/SOUTH AYSEN WHERE
EXPECTED IS 25-50MM. A SHORT WAVE TROUGH IN THE MID TO UPPER
LEVELS WILL ENHANCE THE DIVERGENCE FOR THE SYSTEM...PROVIDING
VENTILATION FOR HEAVY PRECIPITATION. THE SYSTEM IS VERY
PROGRESSIVE AND IT IS EXPECTED TO PROPAGATE QUICKLY. TO THE
NORTH...THE COLD FRONT CONTINUES ITS NORTH AND EAST
MOVEMENT...EXTENDING FROM NORTHWEST ARGENTINA...THROUGH ENTRE
RIOS...AND ALONG THE RIO DE LA PLATA REGION BY SATURDAY EVENING.
WITH THE UPPER JET INTENSIFYING OVER THE REGION...EXPECT MAXIMA OF
25-50MM IN EASTERN ARGENTINA WITH A MODERATE RISK OF SEVERE
WEATHER. THE NORTHEAST REGION OF ARGENTINA CAN EXPECT MAXIMA OF
20-35MM WITH A SLIGHT RISK OF SEVERE WEATHER. BY
SUNDAY...CONDITIONS IN SOUTH CHILE ARE EXPECTED TO BECOME DRY AS
THE PRESENCE OF MOISTURE DECREASES AND A RIDGE BRIEFLY ENTERS THE
REGION IN THE UPPER LEVELS. EXPECT MAXIMA OF 15-20MM WITH A CHANCE
OF MOUNTAIN SNOW. MOST OF ARGETINA IS ALSO EXPECTED TO BECOME
RELATIVELY DRY WITH THE EXCEPTION OF NORTH ARGENTINA DUE TO THE
COLD FRONT PASSAGE.
CASTELLANOS...(WPC)
CLICK HERE TO GO TO PREVIOUS BULLETINS.
Main Text Page