210  
FXSA20 KWBC 131357  
PMDSA  
 
SOUTH AMERICA SYNOPTIC DISCUSSION - INTERNATIONAL DESKS  
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD  
856 AM EST MON NOV 13 2017  
 
GFS DATA AT FTPPRD.NCEP.NOAA.GOV/PUB/DATA/NCCF/COM/GFS/PROD/  
 
SYNOPSIS (VALID FROM NOV 13 AT 0000 UTC): AT 200  
HPA...DISORGANIZED CELL OF THE SUBTROPICAL RIDGE EXTENDS OVER THE  
CONTINENT TO THE NORTH OF 20S. THIS IS VENTING DEEP CONVECTION  
ACROSS BAHIA-TOCANTINS/GOIAS IN BRASIL-SOUTHERN PARA/MATO  
GROSSO-ACRE/RONDONIA AND AMAZONAS TO THE NORTHWEST. CONVECTION IS  
ALSO CLUSTERING ON THE CENTRAL-NORTHERN JUNGLE OF PERU TO SOUTHERN  
COLOMBIA.  
 
THE 250 HPA JET ANALYSIS SHOWS A FINGER OF THE SOUTHERN POLAR WITH  
ENTRANCE AT 57S 100W...THEN ALONG 61S 90W...EXITING AT 60S 77W. IT  
REFORMS AT 50S 72W...ALONG A 134KT MAXIMUM AT 48S 64W...46S  
56W...EXITING AT 47S 46W. THE NORTHERN POLAR HAS ITS ENTRANCE AT  
33S 110W...THEN ALONG 29S 105W...29S 99W...33S 93W...A 128KT  
MAXIMUM AT 40S 86W...44S 78W...A 131KT MAXIMUM AT 45S 70W...43S  
59W...39S 49W...32S 47W...EXITING AT 28S 44W. THE SUBTROPICAL JET  
HAS ITS ENTRANCE AT 29S 120W...THEN ALONG 26S 110W...25S 97W...33S  
86W...40S 76W...40S 62W...34S 54W...EXITING AT 29S 51W. IT REFORMS  
AT 24S 62W...THEN ALONG 20S 53W...20S 44W...25S 36W...A 141KT  
MAXIMUM AT 32S 30W...37S 22W...A 175KT MAXIMUM AT 38S 08W...AND  
34S 00W.  
 
AT 500 HPA...LONG WAVE TROUGH EXTENDS FROM A LOW AT 47S  
88W...ALONG 30S 103W...TO 20S 107W. THIS SUSTAINS AN INDUCED RIDGE  
TO THE EAST THAT EXTENDS OVER ARGENTINA. SHORT WAVE PERTURBATIONS  
ARE STREAMING TO THE SOUTH...WITH ONE PULLING ACROSS THE DRAKE  
PASSAGE AS ANOTHER LIFTS ACROSS 50W. ON THE NORTHERN STREAM...A  
SHORT WAVE TROUGH EXTENDS BETWEEN 50W-30W TO 20S WHILE CENTERING  
ON A CLOSED LOW AT 35S 39W.  
 
AT LOW LEVELS...PROGRESSIVE FRONT ON THE SOUTHERN STREAM EXTENDS  
FROM AN OCCLUDED 980 HPA LOW AT 64S 62W...A 982 HPA LOW AT 61S  
60W...58S 62W...57S 71W...61S 79W...A 968 HPA LOW AT 67S 89W...61S  
86W...AND 58S 94W. A FRONT ON THE NORTHERN STREAM EXTENDS FROM AN  
OCCLUDED 962 HPA LOW AT 55S 47W...ALONG A 962 HPA LOW AT 58S  
44W... 54S 41W...51S 43W...A 990 HPA LOW AT 49S 48W...43S  
50W...38S 58W... 40S 67W...A 1004 HPA LOW AT 44S 80W...38S  
80W...32S 86W...AND 29S 90W. A RIDGE TO THE NORTH CENTERS ON TWO  
1017 HPA HIGHS...WITH ONE AT 30S 83W AND THE OTHER AT 20S 91W.  
OVER THE ATLANTIC...BROAD OCCLUDED TROUGH ON THE NORTHERN STREAM  
CENTERS ON TWO 994 HPA LOWS...WITH ONE AT 34S 39W AND THE OTHER  
39S 35W. THE LATTER EXTENDS A FRONT ALONG A 1008 HPA TRIPLE POINT  
LOW AT 36S 24W...33S 25W...31S 27W...A 1006 HPA LOW AT 29S  
29W...23S 31W...20S 37W...A 1006 HPA LOW AT 22S 45W...MATO GROSSO  
DO SUL TO CENTRAL PARAGUAY. CONVECTION IS CLUSTERING FAR TO THE  
NORTH ALONG A TROUGH OVER CENTRAL BRASIL.  
 
OVIEDO...SHN (ARGENTINA)  
VANNUCCI...SMN (ARGENTINA)  
RIVAS...SENAMHI (PERU)  
DAVISON...WPC (USA)  

 
 
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