THE WEATHER PREDICTION CENTER

COLLEGE PARK, MD


SOUTH AMERICAN MODEL DISCUSSION




SOUTH AMERICA FORECAST DISCUSSION - INTERNATIONAL DESKS
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
1049 AM EDT THU OCT 30 2014

GFS DATA AT FTPPRD.NCEP.NOAA.GOV/PUB/DATA/NCCF/COM/GFS/PROD/

MODEL DISCUSSION (VALID FROM OCTOBER 30 AT 00UTC): GLOBAL MODELS
AND ENSEMBLE MEMBERS CONTINUE IN GOOD AGREEMENT ON FORECAST
EVOLUTION...AS THEY SHOW A GRADUAL TRANSITION TO A PATTERN
CHARACTERIZED BY SHORTER WAVES BY EARLY NEXT WEEK. FORECAST
CONFIDENCE IS HIGH...WITH SOME DIFFERENCES IN SPEED OF THE SYSTEM
SOUTH OF 50S BY DAY 05 AND ON.

COLD AIRMASS IN THE SOUTHERN CONE THAT PRODUCE SNOWFALL IN PARTS
OF SOUTHERN CHILE AND ARGENTINA WILL CONTINUE DOMINATING LATITUDES
SOUTH OF 40S THROUGH SATURDAY EVENING/EARLY SUNDAY MORNING. THIS
WILL STILL SUSTAIN WANING SHOWERS ACROSS PARTS OF SOUTH-CENTRAL
CHILE THROUGH FRIDAY WITH ACCUMULATIONS OF 05-10MM/DAY...AND
ISOLATED RAIN/SNOW SHOWERS IN THE MAGALLANES REGION OF
CHILE/EXTREME EASTERN PATAGONIA. MID-UPPER RIDGE IS THEN TO START
BUILDING FROM THE EASTERN PACIFIC INTO THE SOUTHERN CONE
DOMINATING THE REGION DURING MONDAY AND TUESDAY. AS RIDGE BUILDS
TO THE SOUTH...MODELS ARE FORECASTING THE DEVELOPMENT OF A CLOSED
UPPER LOW BETWEEN CONCEPCION AND PUERTO MONTT IN CHILE. MOISTURE
IS LIMITED...YET THIS WILL STILL SUSTAIN SHOWERS ESPECIALLY IN THE
CORDILLERA AND PRE-CORDILLERA OF THESE REGIONS WITH DAILY
ACCUMULATIONS OF 00-05MM/DAY DURING FRIDAY...DECREASING AFTERWARDS.

OTHER REGION OF INTEREST ARE CENTRAL PORTIONS OF THE
CONTINENT...AS SYSTEM THAT PRODUCED SEVERE WEATHER AND HEAVY
RAINFALL IN CENTRAL/EASTERN ARGENTINA AND URUGUAY/SOUTHERN BRASIL
IS MEANDERING NORTHWARD. UPPER FORCING IS DECREASING AS THE FRONT
IS MOVING INTO A REGION OF LESS BAROCLINICITY. CONVECTIVE
INSTABILITY REMAINS HOWEVER HIGH. THIS WILL CONTINUE SUSTAINING
SCATTERED THUNDERSTORM DEVELOPMENT AS THE SYSTEM MOVES NORTH.
THROUGH EARLY FRIDAY...EXPECTING MAXIMUM ACCUMULATIONS OF
20-45MM/DAY AFFECTING SOUTHEASTERN PARAGUAY INTO NORTHEASTERN
ARGENTINA AND SOUTHERN BRASIL. SCATTERED THUNDERSTORMS ARE ALSO
EXPECTED TO THE WEST WITH LIGHTER AMOUNTS. BY FRIDAY INTO EARLY
SATURDAY...EXPECTING SIMILAR ACCUMULATIONS ACROSS MID-SECTIONS OF
THE CONTINENT STRETCHING FROM SOUTHERN BOLIVIA INTO
PARAGUAY/SOUTHERN BRASIL. BY SATURDAY INTO EARLY
SUNDAY...EXPECTING MAXIMA OF 20-40MM/DAY IN THUNDERSTORMS
STRETCHING FROM CENTRAL PARAGUAY INTO SOUTHERN BRASIL...AND AN
INCREASE TO MAXIMA OF 40-80MM/DAY ACROSS LOWER PORTIONS OF
BOLIVIA. AMOUNTS ARE TO START DECREASING AFTERWARDS.

NORTH ACROSS THE CONTINENT...LARGEST RAINFALL AMOUNTS WILL
INITIALLY CONCENTRATE ACROSS CENTRAL PARTS OF BRASIL WHERE
EXPECTING MAXIMA OF 20-45MM/DAY. AMOUNTS ARE TO GRADUALLY DECREASE
AS THE FOCUS OF STRONGEST CONVECTION SHIFTS TO THE SOUTHWEST INTO
BOLIVIA/RONDONIA/WESTERN MATO GROSSO/MATO GROSSO DO SUL. ACROSS
THE CENTRAL ANDES...EXPECTING AN INCREASE IN ACTIVITY DURING THE
WEEKEND AS UPPER TROUGH PUSHES FROM THE WEST...AND DEEP-LAYER
MOISTURE IS ADVECTED FROM THE AMAZON. THIS WILL LEAD TO MAXIMA OF
15-20MM/DAY PEAKING AT 15-20MM/DAY ACROSS THE CENTRAL ANDES OF
PERU.

CAROCA...DMC (CHILE)
DURAN...SENAHMI (PERU)
GALVEZ...WPC (USA)




Last Updated: 1049 AM EDT THU OCT 30 2014