780  
FXSA20 KWBC 191317  
PMDSA  
 
SOUTH AMERICA SYNOPTIC DISCUSSION - INTERNATIONAL DESKS  
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD  
916 AM EDT THU OCT 19 2017  
 
GFS DATA AT FTPPRD.NCEP.NOAA.GOV/PUB/DATA/NCCF/COM/GFS/PROD/  
 
SYNOPSIS (VALID FROM OCT 18 AT 0000 UTC): AT 200 HPA...A BROAD  
RIDGE EXTENDS OVER CENTRAL SOUTH AMERICA BETWEEN 70W AND 50W AND  
SOUTH INTO NORTHERN PARAGUAY/MATO GROSSO DO SUL. A TROUGH LIES TO  
THE WEST ALONG 90W...WHILE THE CAVADO DO NORDESTE LIES FROM 23S  
30W INTO THE COASTS OF ALAGOAS/SERGIPE AND PERNAMBUCO IN THE  
NORDESTE. CONVECTION IS CLUSTERING IN THE WESTERN AMAZON BASIN  
BETWEEN NORTHERN RONDONIA AND AMAZONAS IN BRASIL.  
 
THE UPPER JET ANALYSIS SHOWS THE SOUTHERN POLAR JET FORMING AT 52S  
50W ALONG 53S 39W...A 145KT MAXIMA AT 52S 25W. THE NORTHERN POLAR  
JET FORMS A BRANCH AT 41S 104W ALONG 41S 93W...42S 81W...EXITING  
AT 39S 70W. IT REFORMS AT 38S 63W ALONG 43S 59W...A 162KT MAXIMA  
AT 48S 490W...48S 24W...EXITING AT 37S 08W. ANOTHER BRANCH FORMS  
AT 28S 113W ALONG 35S 104W...EXITING AT 36S 89W. THE SUBTROPICAL  
JET EXTENDS ALONG 22S 120W...23S 111W...29S 97W...EXITING AT 23S  
84W. ANOTHER BRANCH FORMS AT 29S 71W ALONG 27S 65W...EXITING AT  
32S 60W. IT REFORMS AT 35S 57W ALONG 39S 52W...A 124KT MAXIMA AT  
41S 45W...EXITING AT 39S 35W. ANOTHER BRANCH FORMS AT 17S 75W  
ALONG 23S 67W...EXITING AT 28S 55W.  
 
AT 500 HPA...IN THE SOUTHERN STREAM...A BROAD LOW IS CROSSING INTO  
THE WEDDELL SEA FROM THE WEST WHILE EXTENDING NUMEROUS SHORT WAVE  
TROUGHS AROUND ITS PERIPHERY. ONE CENTERS AT 70S 65W AND ANOTHER  
AT 60S 60W. A TROUGH EXTENDS TO THE NORTHWEST ACROSS THE DRAKE  
PASSAGE INTO A LOW AT 52S 85W...AND INTO ANOTHER LOW AT 44S 99W.  
TO THE EAST OF THIS TROUGH...ZONAL FLOW EXTENDS OFF THE COAST OF  
CHILE. AN ELONGATED TROUGH EXTENDS FROM THE SOUTHERN ATLANTIC AT  
50S 53W INTO BAHIA BLANCA AT 38S 62W...INTO NORTHWESTERN  
ARGENTINA. A SHORT WAVE TROUGH EXTENDS ACROSS EASTERN URUGUAY INTO  
EASTERN SANTA CATARINA.  
 
AT LOW LEVELS...AN ILL-DEFINED FRONT EXTENDS FROM 44S 61W ALONG A  
1010 HPA LOW AT 49S 68W...46S 70W...45S 74W...A 1010 HPA LOW AT  
51S 80W. A 1008 HPA OCCLUDED LOW AT 53S 84W EXTENDS A FRONT ALONG  
48S 87W...49S 96W. A 1029 HPA HIGH CENTERS AT 35S 84W IN THE  
EASTERN PACIFIC...AND EXTENDS A RIDGE INTO THE BIO BIO/ARAUCANIA  
REGIONS IN CHILE...AND INTO A 1017 HPA POLAR HIGH AT 36S 66W. TO  
THE EAST...A FRONT EXTENDS ALONG A 996 HPA LOW AT 50S 48W...46S  
47W...43S 48W...A 1008 HPA LOW AT 41S 52W...39S 53W...38S 55W...A  
1010 HPA LOW AT 35S 60W...32S 61W...30S 64W. STRONG CONVECTION WAS  
OCCURRING IN CENTRAL ARGENTINA. A FRONT EXTENDS ALONG 38S 46W INTO  
A 1008 HP-A LOW AT 35S 53W...32S 51W...30S 53W...A 1002 HPA LOW AT  
30S 60W...28S 65W.  
 
VANNUCCI...SMN (ARGENTINA)  
RIVAS...SENAMHI (PERU)  
GALVEZ...WPC (USA)  

 
 
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