Prognostic Meteorological Discussion
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FXSA20 KWBC 011712
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SOUTH AMERICA FORECAST DISCUSSION - INTERNATIONAL DESKS
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
111 PM EDT FRI AUG 01 2014

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

MODEL DISCUSSION (VALID FROM AUGUST 1 AT 00UTC): MODELS ARE IN
EXCELLENT AGREEMENT THROUGH THE CYCLE...ESPECIALLY ACROSS
CONTINENTAL AREAS OF CENTRAL AND SOUTHERN SOUTH AMERICA. SOME
DIFFERENCES ARISE AFTER 96 HOURS IN THE EXTREME SOUTHEASTERN
PACIFIC.

MOST REMARKABLE EVENT THROUGH THE FORECAST CYCLE WILL BE MODERATE
TO HEAVY RAINS AFFECTING CENTRAL/SOUTHERN CHILE. A TIGHT BELT IF
WESTERLIES IS AFFECTING THE REGION COUPLED WITH A PLUME OF
SUBTROPICAL MOISTURE. THIS IS ENHANCING LOW-LEVEL MOISTURE
CONVERGENCE AGAINST THE COAST AND ANDES. FURTHERMORE...UPPER
DIVERGENCE WILL BE FAVORABLE FOR VENTILATION THROUGH 24-36
HRS...LEADING TO LARGEST ACCUMULATIONS THROUGH 36 HOURS BETWEEN
THE BIO BIO AND LOS LAGOS REGIONS. EXPECTING MAXIMA OF 40-80MM/DAY
THROUGH SATURDAY MORNING. AFTERWARDS...AMOUNTS ARE TO DECREASE TO
MAXIMA OF 25-50MM/DAY...WHILE REGION OF HEAVIEST PRECIPITATION
EXTENDS FROM THE MAULE REGION SOUTH INTO THE ARAUCANIA REGION.
LIGHTER ACCUMULATIONS ARE EXPECTED FURTHER SOUTH.

OTHER REGION OF INTEREST IS THE RIO DE LA PLATA-SOUTHERN BRASIL
AREA. SHORTWAVE PERTURBATIONS WILL PRODUCE SEVERAL ROUNDS OF
CONVECTION. UPPER JET DYNAMICS ARE HOWEVER UNFAVORABLE...THUS
EXPECTING AMOUNTS LIMITING TO MAXIMA OF 20-40MM/DAY IN STRONGEST
STORMS. THROUGH SATURDAY MORNING...EXPECTING LARGEST ACCUMULATIONS
TO AFFECT RIO GRANDE DO SUL PRODUCING MAXIMA OF 20-35MM/DAY.
EXPECTING REDEVELOPMENT ACROSS THE RIO DE LA PLATA AND ESPECIALLY
SOUTHERN URUGUAY DURING SATURDAY INTO SUNDAY...WITH ISOLATED
MAXIMA OF 20-40MM/DAY. AS SYSTEM PROGRESSES
NORTHEASTWARD...EXPECTING ACCUMULATIONS OF 15-30MM/DAY TO AFFECT
SOUTHERN RIO GRANDE DO SUL AND NORTHEASTERN URUGUAY ON SUNDAY INTO
MONDAY.

OTHER REGION OF INTEREST IS THE COAST OF BAHIA AND PARTS OF THE
COASTAL NORDESTE. A STATIONARY FRONT WILL CONTINUE BEING A SOURCE
OF LOW-LEVEL MOISTURE CONVERGENCE. THIS SYSTEM WILL LEAD TO0
MAXIMA OF 15-25MM/DAY EARLY IN THE CYCLE WITH AMOUNTS DECREASING
THROUGH THE WEEKEND.

PATTERN IS CHANGING INTO A LONG WAVE ONE...AND A NEW UPPER TROUGH
IS FORECAST TO ARRIVE INTO SOUTHERN CHILE DURING MID-NEXT WEEK
LEADING TO ANOTHER ROUND OF RAINS. DETAILS WILL BECOME MORE CLEAR
ON MONDAY.

JALFIN ... SMN (ARGENTINA)
GALVEZ ... WPC (USA)
$$




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