533  
FXSA20 KWBC 071422  
PMDSA  
 
SOUTH AMERICA SYNOPTIC DISCUSSION - INTERNATIONAL DESKS  
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD  
922 AM EST TUE NOV 07 2017  
 
GFS DATA AT FTPPRD.NCEP.NOAA.GOV/PUB/DATA/NCCF/COM/GFS/PROD/  
 
SYNOPSIS (VALID FROM NOV 07 AT 0000 UTC): AT 200 HPA A CLOSED LOW  
CENTERS OVER AMAPA IN BRASIL...ANCHORING A SHORT WAVE TROUGH THAT  
EXTENDS BETWEEN PARA AND NORTH COAST OF BRASIL. A RIDGE TO THE  
SOUTH EXTENDS FROM PERU...ACROSS BOLIVIA-MATO GROSSO TO MINAS  
GERAIS/BAHIA. THE RIDGE ANCHORS ON TWO CLOSED HIGHS...WITH ONE  
OVER NORTHERN BOLIVIA AND THE OTHER NEAR SALVADOR DE BAHIA. THE  
RIDGE ALOFT CONTINUES TO VENT ORGANIZED DEEP CONVECTION...WITH  
ACTIVITY CLUSTERING BETWEEN 10S-20S.  
 
AT 250 HPA...A FINGER OF THE SOUTHERN POLAR HAS ITS ENTRANCE AT  
43S 111W...THEN ALONG 44S 102W...EXITING AT 47S 95W. IT REFORMS  
BETWEEN 57S 76W AND 64S 77W. ANOTHER BRANCH OF THE SOUTHERN POLAR  
TO THE EAST HAS ITS ENTRANCE AT 70S 45W...THEN ALONG 64S 41W...56S  
44W...50S 43W...EXITING AT 44S 41W. THE NORTHERN POLAR LIES ALONG  
35S 120W...37S 107W...38S 89W...EXITING AT 38S 78W. IT REFORMS AT  
40S 67W...ALONG 41S 61W...33S 49W...31S 42W...30S 33W...36S  
21W...AND 42S 13W. THE SUBTROPICAL JET LIES ALONG 31S 120W...A  
139KT MAXIMUM AT 33S 110W...A 144KT MAXIMUM AT 35S 101W...33S  
90W...EXITING AT 27S 83W. IT REFORMS AT 22S 72W...THEN ALONG 23S  
62W...24S 53W...A 121KT MAXIMUM AT 26S 46W...27S 31W...31S  
18W...EXITING AT 28S 15W.  
 
AT 500 HPA...BROAD TROUGH DOMINATES THE FLOW OVER THE SOUTHEAST  
PACIFIC...ENVELOPING AREA BETWEEN 130W-75W AND TO THE SOUTH OF  
30S. THE TROUGH PRESSES AGAINST A LONG WAVE RIDGE TO THE EAST THAT  
EXTENDS FROM CENTRAL PROVINCES IN ARGENTINA...ALONG THE COAST OF  
PATAGONIA TO THE ANTARCTIC PENINSULA. SHORT WAVE PERTURBATIONS ON  
THE NORTHERN STREAM ARE SPREADING AHEAD OF THE LONG WAVE TROUGH...  
WITH ONE EXTENDING ALONG 80W TO 35S AS ANOTHER PULLS ACROSS  
CENTRAL CHILE TO CUYO IN ARGENTINA. FARTHER EAST...LONG WAVE  
TROUGH OVER THE SOUTH ATLANTIC EXTENDS BETWEEN 50W-10W TO THE  
SOUTH OF 24S.  
 
AT LOW LEVELS...BROAD TROUGH OVER THE SOUTHEAST PACIFIC CENTERS ON  
AN OCCLUDED 962 HPA LOW AT 63S 102W. THIS EXTENDS AN ELONGATED  
FRONT ALONG A 976 HPA LOW AT 67S 108W...69S 103W...68S 99W...A 970  
HPA LOW AT 67S 94W...70S 86W...66S 82W...A 984 HPA LOW AT 63S  
81W...61S 70W...56S 66W...53S 69W...A 1010 HPA LOW AT 50S  
70W...47S 69W...44S 70W...A 1014 HPA LOW AT 42S 75W...36S 77W...TO  
33S 85W. A FRONT ON THE NORTHERN STREAM...MEANWHILE...EXTENDS  
ALONG A 1018 HPA LOW AT 37S 54W...34S 57W...34S 62W...A 1014 HPA  
LOW AT 36S 66W...33S 67W...TO MENDOZA IN ARGENTINA. THIS SUSTAINS  
SCATTERED CONVECTION ACROSS CENTRAL PORTIONS OF ARGENTINA. FARTHER  
EAST...OVER THE SOUTH ATLANTIC...AN OCCLUDED 954 HPA LOW AT 65S  
15W ANCHORS A BROAD TROUGH ON THE SOUTHERN-NORTHERN STREAM  
FLOW...WITH AN ELONGATED FRONT EXTENDING ALONG A 1006 HPA LOW AT  
48S 09W...46S 11W...43S 14W...A 1006 HPA LOW AT 40S 17W...37S  
17W...32S 22W...A 1010 HPA LOW AT 29S 27W...23S 31W...21S  
37W...RIO DE JANEIRO/NORTHERN SAO PAULO TO MATO GROSSO DO  
SUL/CENTRAL PARAGUAY. ORGANIZED DEEP CONVECTION WAS CLUSTERING  
BETWEEN MATO GROSSO AND SOUTHERN MINAS GERAIS. A RIDGE TO THE  
SOUTH CENTERS ON A 1025 HPA HIGH AT 44S 56W AND A 1023 HPA HIGH AT  
32S 44W.  
 
OVIEDO...SHN (ARGENTINA)  
VANNUCCI...SMN (ARGENTINA)  
RIVAS...SENAMHI (PERU)  
DAVISON...WPC (USA)  

 
 
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