213
FXSA20 KWBC 251936
PMDSA
SOUTH AMERICA FORECAST DISCUSSION - INTERNATIONAL DESKS
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
236 PM EST MON NOV 25 2024
GFS DATA AT FTPPRD.NCEP.NOAA.GOV/PUB/DATA/NCCF/COM/GFS/PROD/
SOUTH AMERICAN FORECAST BULLETIN FOR 25 NOV 2024 AT 1900 UTC: THE
LARGE SCALE ANALYSIS SHOWS AN UPPER CONVERGENT MADDEN-JULIAN
OSCILLATION TO CONTINUE BEING A DOMINANT FEATURE THROUGH THE REST
OF THE WEEK AND INTO THE WEEKEND. THIS WILL LIKELY LIMIT THE AREAS
OF HEAVIEST PRECIPITATION THROUGH THE FORECAST CYCLE.
IN THE SOUTHERN STREAM...A BDOAR UPPER TROUGH CENTERS ON A CUTOFF
LOW OFF THE COAST OF SOUTHERN CHILE. THIS SYSTEM IS FORECAST TO
PROGRESS EASTWARD SLOWLY...WHICH WILL ALLOW FOR AN EXTENDED PERIOD
OF DECREASING SURFACE PRESSURES AND EASTERLY FLOW IN PORTIONS OF
PATAGONIA. THIS WILL RESULT IN MODERATE 3-DAY RAINFALL
ACCUMULATION EAST OF THE ANDES. ON MONDAY...CONVECTION ALONG THE
FRONT IN SOUTHERN AND AUSTRAL CHILE WILL FAVOR MAXIMA OF 15-30MM.
DUE TO ENHANCED INSTABILITY AND DYNAMICS OF AN ASSOCIATED
NEGATIVELY TILTED UPPER TROUGH...EXPECT MAXIMA OF 15-30MM. EAST OF
THE ANDES EXPECT MAXIMA OF 15-20MM AND A MARGINAL RISK FOR
SEVERITY DEVELOPING IN SOUTHERN CHUBUT...WHILE SIMILLAR CONDITIONS
DEVELOP IN LA PAMPA AND THE SOUTHWEST BUENOS AIRES PROVINCE. ON
TUESDAY...ENHANCED INSTABILITY WILL FAVOR ISOLATED MAXIMA OF
15-20MM IN LOS LAGOS/LOS RIOS IN SOUTHERN CHILE WITH A CONTINUED
RISK FOR ISOLATED THUNDERSTORMS. EAST OF THE ANDES EXPECT MAXIMA
OF 15MM. ON WEDNESDAY...EXPECT MAXIMA OF 15MM AND A MARGINAL RISK
FOR SEVERITY FROM COMODORO RIVADAVIA INTO PENINSULA VALDEZ.
THE BOLIVINA HIGH/SUBTROPICAL UPPER RIDGE IN SOUTH AMERICA
CONTINUES TO BE A DOMINANT FEATURES IN CENTRAL PORTIONS OF THE
CONTINENT. THE HIGH EXTENDS AS FAR SOUTH AS NORTH-CENTRAL
ARGENTINA...WHERE IT IS VENTILATING WITH DHORT WAVE PERTURBATIONS
PROPAGATING IN THE MID-UPPER WESTERLIES. IN THE LOWER
TROPOSPHERE...PRECIPITABLE WATER HAS REACHED VALUES OF 45-55MM
FROM NORTHERN URUGUAY INTO TUCUMAN/SALTA. ALTHOUGH SURFACE FRONTS
ARE NOT EXPECTED TO REACH THIS REGION...EXPECT A LOW-LEVEL THERMAL
GRADIENT TO DEVELOP IN ASSOCIATION WITH PRECIPITATION AND ENHANCE
A LOW-LEVEL TROUGH STRUCTURE. THROUGH EARLY TUESDAY...EXPECT
MAXIMA OF 25-50MM AND A SLIGHT RISK OF SEVERITY DEVELOPING IN
NORTHEAST ARGENTINA/NORTHERN URUGUAY IN ASSOCIATION WITH A SHORT
WAVE UPPER TROUGH. SIMILAR AMOUNTS ARE EXPECTED IN SALTA/TUCUMAN
AS ENHANCED INSTABILITY AND UPSLOPE LOW-LEVEL WINDS TRIGGER DEEP
CONVECTION. ON TUESDAY...EXPECTMAXIMA OF 20-35MMFROM
CORRIENTES/SANTA FE INTO SALTA/JUJUY AND TARIJA IN ASSOCIATION
WITH LOW-LEVEL JET CONVERGENCE AND ENHANCEMENT BY THE SURFACE
TROUGH. IN CENTRAL ARGENTINA AND THE RIO DE LA PLATA/SOUTHERN RIO
GRANDE DO SUL EXPECT MAXIMA OF 15-25MM WITH A MARGINAL RISK OF
SEVERITY. ON WEDNESDAY...EXPECT THE LARGEST AMOUNTS CLUSTERING IN
NORTHERN ARGENTINA AND SOUTHERN PARAGUAY WHERE EXPECT MAXIMA OF
25-50MM. IN RIO GRANDE DO SUL...URUGUAY AND ENTRE RIOS AND SANTA
FE EXPECT MAXIMA OF 20-35MM WITH A MODERATE RISK FOR SEVERITY.
A SURFACE FRONT EXTENDS FROM THE SOUTH ATLANTIC INTO NORTHEAST
BRASIL AND HAS BECOME STATIONARY. AN UPPER TROUGH THAT HAS BEEN
ENHANCING CONVECTION WITH THIS SYSTEM IS GRADUALLY
WEAKENING...WHICH WILL YIELD TO A DECREASE IN AMOUNTS FROM MAXIMA
OF 20-35MM ON MONDAY TO ISOLATED MAXIMA OF 15-25MM BY WEDNESDAY.
GALVEZ...(WPC)
CLICK HERE TO GO TO PREVIOUS BULLETINS.
Main Text Page