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South American Forecast Discussion
 
(Latest Discussion - Issued 1727Z Sep 19, 2019)
 
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Abbreviations and acronyms used in this product


SOUTH AMERICA FORECAST DISCUSSION - INTERNATIONAL DESKS
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
127 PM EDT THU SEP 19 2019

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

FORECAST DISCUSSION FROM SEP 19/00UTC: MODELS CONTINUE IN
AGREEMENT THROUGH 120 HRS OVER THE CONTINENT. AFTER THIS
PERIOD...THEY START DIVERGING IN SOUTHERN BRASIL AND PARAGUAY.
ALSO...SIGNIFICANT DISCREPANCIES ARISE AFTER THIS PERIOD REGARDING
A SHORT WAVE TROUGH ARRIVING INTO SOUTHERN CHILE ON DAYS 5 TO 6.

AN EVENT OF INTEREST IS SEVERE CONVECTION DEVELOPING IN SOUTHEAST
PARAGUAY...NORTHEAST ARGENTINA AND PARANA/SANTA CATARINA/SOUTHERN
SAO PAULO IN BRASIL ON THURSDAY. AT UPPER LEVELS...A POLAR TROUGH
AXIS IS CROSSING THE REGION ON THURSDAY. THIS IS INTERACTING WITH
A MOIST LOW-LEVEL JET FROM THE NORTH AND MARGINALLY FAVORABLE
UPPER JET DYNAMICS. HOWEVER...INSTABILITY AND DYNAMICALLY-INDUCED
ASCENT WILL BE SUFFICIENT TO CONTINUE TRIGGERING A FEW SEVERE
CELLS. THESE WILL SUSTAIN ACCUMULATIONS OF 35-70MM/DAY THROUGH
EARLY FRIDAY. BY FRIDAY...UPPER JET DYNAMICS WILL BECOME LESS
FAVORABLE FOR ASCENT. HOWEVER...ENHANCED LOW-LEVEL CONVERGENCE
ALONG A COLD FRONT EXTENDING FROM PARANA-BRASIL ACROSS SOUTHWEST
MATO GROSSO DO SUL AND INTO CENTRAL BOLIVIA WILL SUSTAIN
CONVECTIVE DEVELOPMENT ONCE AGAIN FROM EXTREME EASTERN PARAGUAY
INTO PARANA/SANTA CATARINA IN BRASIL. EXPECTING MAXIMA OF
15-20MM/DAY IN PARAGUAY AND WESTERN SOUTHERN BRASIL. HOWEVER...IN
EASTERN PARANA AND SANTA CATARINA EXPECTING MAXIMA OF 25-50MM/DAY.
NOTICE THAR THERE IS A MARGINAL RISK FOR SEVERE CONVECTION. THE
RISK DECREASES AFTERWARDS.

THIS PRODUCT WILL BECOME AVAILABLE AGAIN ON MONDAY SEPTEMBER 23.

CORONEL...DMH (PARAGUAY)
ROMAN...SENAMHI (PERU)
GALVEZ...WPC (USA)