239  
FXSA20 KWBC 021305  
PMDSA  
 
SOUTH AMERICA SYNOPTIC DISCUSSION - INTERNATIONAL DESKS  
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD  
905 AM EDT THU NOV 02 2017  
 
GFS DATA AT FTPPRD.NCEP.NOAA.GOV/PUB/DATA/NCCF/COM/GFS/PROD/  
 
SYNOPSIS (VALID FROM NOV 02 AT 0000 UTC): A 200 HPA HIGH NEAR 08S  
66W ANCHORS A RIDGE THAT EXTENDS FROM SOUTHERN PERU/NORTHERN  
BOLIVIA TO BAHIA/MINAS GERAIS IN BRASIL. THE RIDGE UNDERCUTS A  
TROUGH TO THE NORTH THAT CENTERS ON A CLOSED LOW AT 01S 39W. THE  
RIDGE ALOFT IS VENTING ORGANIZED DEEP CONVECTION ACROSS CENTRAL  
PERU-ACRE/RONDONIA IN BRASIL. OTHER CONVECTION OVER BRASIL WAS  
CLUSTERING ACROSS BAHIA-MINAS GERAIS AND PORTIONS OF PARA.  
 
THE 250 HPA ANALYSIS SHOWS THE SOUTHERN POLAR WITH ENTRANCE AT 64S  
104W...THEN ALONG A 155KT MAXIMUM AT 63S 77W...59S 59W...EXITING  
AT 55S 40W. IT HAS A BRANCH TO THE NORTH WITH ENTRANCE AT 51S  
101W...THEN ALONG 59S 87W...57S 72W...EXITING AT 54S 62W. A FINGER  
OF THE NORTHERN POLAR HAS ITS ENTRANCE AT 39S 89W...EXITING AT 31S  
80W. IT REFORMS AT 30S 77W....THEN ALONG 36S 69W...43S 59W...39S  
49W...32S 36W...37S 25W...EXITING AT 46S 18W. THE SUBTROPICAL JET  
HAS ITS ENTRANCE AT 21S 85W...THEN ALONG 24S 78W...A 120KT MAXIMUM  
AT 28S 70W...29S 62W...26S 43W...28S 34W...A 142KT MAXIMUM AT 31S  
27W...34S 20W...EXITING AT 38S 13W.  
 
AT 500 HPA...A SHORT WAVE TROUGH EXTENDS FROM 55S 101W TO 37S  
100W. THIS IS PRESSING AGAINST A SKEW RIDGE TO THE EAST THAT  
EXTENDS FROM 30S 100W...ALONG 40S 90W...50S 85W...TO 67S 115W.  
BROAD TROUGH TO THE EAST DOMINATES THE FLOW ACROSS THE SOUTHERN  
CONE. THE TROUGH ENVELOPS AREA BETWEEN 85W-60W AND TO THE SOUTH OF  
20S...WHILE CENTERING ON A CLOSED LOW AT 41S 80W. THIS IS  
PROVIDING DYNAMICAL SUPPORT TO AN AREA OF ORGANIZED DEEP  
CONVECTION OVER THE BUENOS AIRES PROVINCE/ENTRE RIOS IN ARGENTINA.  
FARTHER EAST...A SHORT WAVE RIDGE EXTENDS ALONG 57W TO 47S.  
DOWNSTREAM FROM THIS AXIS ANOTHER TROUGH EXTENDS BETWEEN 45W-15W  
TO 24S.  
 
AT LOW LEVELS...AN ELONGATED FRONT ON THE SOUTHERN STREAM EXTENDS  
FROM A 982 HPA LOW AT 57S 42W...54S 40W...52S 43W...A 996 HPA LOW  
AT 54S 53W...54S 57W...54S 62W...A 994 HPA LOW AT 58S 74W...57S  
85W...A 980W HPA LOW AT 58S 101W...55S 97W...A 992 HPA LOW AT 53S  
100W...48S 98W...TO 44S 102W. ON THE NORTHERN STREAM...AN OCCLUDED  
1006 HPA LOW AT 40S 80W EXTENDS A FRONT ALONG A 1008 HPA LOW AT  
45S 69W...42S 64W...39S 63W...37S 64W...A 1008 HPA LOW AT 36S  
68W...29S 75W...26S 84W...TO 24S 92W. THIS SUSTAINS ORGANIZED DEEP  
CONVECTION ACROSS CENTRAL PROVINCES IN ARGENTINA. ANOTHER FRONT  
OVER THE ATLANTIC EXTENDS FROM AN OCCLUDED 968 HPA LOW AT 45S  
25W...A 984 HPA LOW AT 47S 24W...44S 17W...40S 15W...A 1012 HPA  
LOW AT 38S 17W...34S 19W...30S 22W...A 1014 HPA LOW AT 29S  
27W...23S 30W...20S 35W...17S 40W...MINAS GERAIS TO MATO GROSSO DO  
SUL IN BRASIL. SCATTERED CONVECTION WAS CLUSTERING ALONG AND NORTH  
OF THIS FRONT OVER BRASIL. A RIDGE OVER THE WESTERN ATLANTIC  
CENTERS ON A 1021 HPA HIGH AT 37S 49W AND A 1021 HPA HIGH AT 28S  
48W.  
 
OVIEDO...SHN (ARGENTINA)  
VANNUCCI...SMN (ARGENTINA)  
RIVAS...SENAMHI (PERU)  
DAVISON...WPC (USA)  

 
 
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