Prognostic Meteorological Discussion
Issued by NWS
Issued by NWS
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313 FXSA20 KWBC 071928 PMDSA SOUTH AMERICA FORECAST DISCUSSION - INTERNATIONAL DESKS NWS WEATHER PREDICTION CENTER COLLEGE PARK MD 327 PM EDT MON OCT 07 2024 GFS DATA AT FTPPRD.NCEP.NOAA.GOV/PUB/DATA/NCCF/COM/GFS/PROD/ SOUTH AMERICAN FORECAST BULLETIN FOR 07 OCT 2024 AT 1930 UTC: A POTENT TROUGH IN THE NORTHERN STREAM IS APPROACHING THE ANDES IN CENTRAL AND NORTHERN CHILE. THE PRESENCE OF A ROBUST RIDGE TO THE EAST IS LIMITING THE EASTWARD PROGRESSION OF THIS SYSTEM...YILENDING TO A SLOW EVOLUTION. THE TROUGH IS LOWERING THE PRESSURES IN REGIONS EAST OF THE ANDES...WHILE STIMULATING SNOWFALL IN THE CORDILLERA IN CENTRAL CHILE. FURTHERMORE...A DEVELOPING CUT OFF LOW IS STIMULATING PRECIPITATION IN PORTIONS OF THE CUARTA AND QUINTA REGION IN CHILE. ON MONDAY...EXPECT AMOUNTS OF 05-10MM/DAY AND ISOLATED MAXIMA OF 15-20MM IN THE CUARTA AND QUINTA REGIONES...WHILE IN THE CORDILELRA EXPECT SNOWFALL AMOUNTS OF 10-20CM/DAY. ON TUESDAY EXPECT SIMILAR AMOUNTS FROM VALPARAISO INTO THE CUARTA REGION WHILE IN THE CORDILLERA EXPECT 15-30CM/DAY. AMOUNTS ARE EXPECTED TO DECREASE THEREAFTER. EAST OF THE ANDES...A FRONT EXTENDS ACROSS SOUTHERN BRASIL INTO SOUTH PARAGUAY AND NORTHERN ARGENTINA. LIFT ENHANCED BY THE APPROACHING UPPER TROUGH IS STIMULATING THE DEVELOPMENT OF THUNDERSTORMS AND A FEW AREAS OF HEAVY PRECIPITATION. THROUGH EARLY TUESDAY...EXPECT 15-20MM/DAY AND MAXIMA OF 30-60MM FROM NORTH-CENTRAL ARGENTINA INTO RIO GRANDE DO SUL IN BRASIL INCLUDING A SLIGHT RISK OF SEVERITY. IN INTERIOR PORTIONS OF NORTHERN ARGENTINA EXPECT MAXIMA OF 15-30MM WITH A MARGINAL RISK OF SEVERITY. IN INTERIOR PORTIONS OF CENTRAL ARGENTINA EXPECT MAXIMA OF 20-35MM AND A RISK OF HEAVY THUNDESTORMS. ON TUESDAY...ENHANCED SOUTHEASTERLY WINDS WILL CONTINUE TO ENHANCE MOISTURE CONVERGENCE IN INTERIOR PORTIONS OF NORTH-CENTRAL ARGENTINA...WHERE EXPECT MAXIMA OF 30-60MM. IN SANTA CATARINA...NORTHERN RIO GRANDE DO SUL INTO CENTRAL PARAGUAY AND NORTHEAST ARGENTINA EXPECT MAXIMA OF 20-45MM WITH A MARGINAL RISK FOR SEVERITY. ALONG THE EASTERN CORDILELRA IN SOUTHERN BOLIVIA AND FAR NORTHERN ARGENTINA EXPECT 10-15MM/DAY AND ISOLATED MAXIMA OF 20-40MM. ON WEDNESDAY...EXPECTTHE FOCUS FOR THE STRONGEST CONVECTION AND LARGEST RAINFALL ACCUMULATION TO CLUSTER IN NORTHERN RIO GRANDE DO SUL AND PARANA IN BRASIL. ECHO TRAINING ALONG A SURFACE FRONT WILL LIKELY ENHANCE ACCUMULATION. EXPECT 15-30MM/DAY AND MAXIMA OF 40-80MM. IN CENTRAL PARAGUAY AND MATO GROSSO DO SUL IN BRASIL EXPECT MAXIMA OF 20-45MM...WHILE FRONTAL CONVECTION ACROSS CENTRAL AND SOUTHEAST BOLIVIA WILL FAVOR MAXIMA OF 20-35MM. ALSO OF INTEREST...ONSHORE FLOW ALONG A SURFACE FRONT IN SOUTHEAST BRASIL WILL DEVELOP MODERATE PRECIPITATION IN ESPIRITO SANTO AND EASTERN RIO DE JANEIRO ON WEDNESDAY...WHERE EXPECT MAXIMA OF 20-40MM. IN THE SOUTHERN CONE...SEVERAL SURFACE FRONTS ARE EXPECTED TO FAVOR INTERMITTENT PRECIPITATION...ALTHOUGH MODERATE AMOUNTS ARE EXPECTED TO REMAIN WEST OF THE ANDES AND OCCUR IN AN ISOLATED MANNER IN AREAS SOUTH OF 50S. EXPECT THE LARGEST ACCUMULATION TO DEVELOP ON WEDNESDAY...PRIMARILY IN ASSOCIATION WITH A TIGHTENING OF THE PRESSURE GRADIENT. THIS WILL FAVOR AMOUTNS OF 10-15MM/DAY AND MAXIMA OF 20-40MM IN AYSEN AND NORTHERN MAGALLANES. GALVEZ...(WPC) $$