198  
FXSA20 KWBC 061619  
PMDSA  
 
SOUTH AMERICA SYNOPTIC DISCUSSION - INTERNATIONAL DESKS  
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD  
1118 AM EST WED DEC 06 2017  
 
GFS DATA AT FTPPRD.NCEP.NOAA.GOV/PUB/DATA/NCCF/COM/GFS/PROD/  
 
SYNOPSIS (VALID FROM DEC 06 AT 0000 UTC): AT 200 HPA...BROAD CELL  
OF THE SUBTROPICAL RIDGE ENVELOPS CONTINENTAL AREA TO THE NORTH OF  
36S WHILE CENTERING ON A CLOSED HIGH AT 18S 56W. NORTH OF THIS  
AXIS...AN ELONGATED TROUGH EXTENDS ALONG 05S 30W...NORTH COAST OF  
BRASIL TO THE GUIANAS. THE UPPER TROUGH SUSTAINS A  
CONVERGENT/SUBSIDENT PATTERN THAT IS INHIBITING ORGANIZED DEEP  
CONVECTION ACROSS PARA-NORTHEAST BRASIL.  
 
THE 250 HPA JET ANALYSIS SHOWS THE SOUTHERN POLAR WITH AXIS ALONG  
53S 120W...57S 103W...A 139KT MAXIMUM AT 56S 89W...53S 73W...55S  
50W...A 120KT MAXIMUM AT 52S 44W...46S 31W...EXITING AT 44S 22W.  
THE NORTHERN POLAR LIES ALONG 47S 120W...54S 98W...EXITING AT 49S  
78W. IT REFORMS AT 48S 71W...ALONG 50S 55W...EXITING AT 45S 43W.  
 
AT 500 HPA...A LOW AMPLITUDE RIDGE EXTENDS BETWEEN 110W-90W TO 64S  
WHILE ORIGINATING ON A CLOSED HIGH AT 33S 106W. EAST OF THIS  
RIDGE...SHORT WAVE TROUGH ON THE SOUTHERN STREAM FLOW EXTENDS FROM  
THE DRAKE PASSAGE TO SOUTHERN CHILE/PATAGONIA IN ARGENTINA.  
ANOTHER SHORT WAVE TROUGH TO THE NORTH...MEANWHILE...EXTENDS FROM  
38S 75W TO 22S 85W. FARTHER EAST...BROAD TROUGH DOMINATES THE FLOW  
OVER THE SOUTH ATLANTIC AS IT EXTENDS BETWEEN 40W-00W AND TO THE  
SOUTH OF 20S.  
 
AT LOW LEVELS...A RIDGE DOMINATES THE NORTHERN STREAM FLOW OVER  
THE EASTERN PACIFIC WHILE CENTERING ON A 1031 HPA HIGH AT 38S  
100W. IN A TIGHT BELT OF WESTERLIES...PROGRESSIVE FRONTS ARE  
STREAMING TO THE SOUTH...WITH ONE EXTENDING FROM AN OCCLUDED 978  
HPA LOW AT 61S 65W...A 982 HPA LOW AT 59S 60W...54S 60W...SRN  
PATAGONIA...A 1014 HPA LOW AT 50S 79W...45S 81W...43S 88W...TO 46S  
94W. ANOTHER FRONT TO THE EAST EXTENDS FROM A 982 HPA LOW AT 50S  
30W...ALONG A 986 HPA LOW AT 48S 26W...43S 30W...41S 35W...41S  
42W...44S 49W...47S 55W...A 1002 HPA LOW AT 51S 64W...TO CENTRAL  
PATAGONIA. ALSO OVER THE ATLANTIC...A RIDGE ON THE NORTHERN STREAM  
CENTERS ON A 1021 HPA HIGH AT 34S 40W. AN ELONGATED FRONT TO THE  
NORTH LIES ALONG 37S 11W...34S 17W...29S 25W...26S  
35W...PARANA-CORRIENTES...TO CORDOBA IN ARGENTINA. AN OLD BOUNDARY  
TO THE EAST AND NORTH OF THE LATTER EXTENDS ALONG A 1016 HPA LOW  
AT 35S 10W...30S 13W...29S 18W...A 1014 HPA LOW AT 29S 24W...25S  
25W...24S 30W...A 1014 HPA LOW AT 25S 35W...TO ESPIRITO SANTO.  
 
OVIEDO...SHN (ARGENTINA)  
POMIER...SENAMHI (BOLIVIA)  
RIVAS...SENAMHI (PERU)  
DAVISON...WPC (USA)  

 
 
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