361  
FXSA20 KWBC 151424  
PMDSA  
 
SOUTH AMERICA SYNOPTIC DISCUSSION - INTERNATIONAL DESKS  
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD  
924 AM EST WED NOV 15 2017  
 
GFS DATA AT FTPPRD.NCEP.NOAA.GOV/PUB/DATA/NCCF/COM/GFS/PROD/  
 
SYNOPSIS (VALID FROM NOV 15 AT 0000 UTC): AT 200 HPA...A HIGH OVER  
RONDONIA IN BRASIL ANCHORS A BROAD RIDGE ACROSS NORTHWEST SOUTH  
AMERICA...AS IT ENVELOPS AREA BETWEEN 85W-60W TO 30S.  
THIS...IN-TURN...SUSTAINS THE NORTHWARD AMPLIFICATION OF A SHORT  
WAVE TROUGH ACROSS THE SOUTHEAST STATES OF BRASIL. IN INTERACTION  
WITH THE RIDGE TO THE WEST THIS SUSTAINS MODERATE TO HEAVY  
CONVECTION ACROSS NORTHEAST BRASIL...WITH OTHER CONVECTION  
CLUSTERING OVER AMAZONAS-ACRE-RONDONIA IN WESTERN  
BRASIL...PERUVIAN JUNGLE AND NORTHERN BOLIVIA.  
 
AT 250 HPA...THE SOUTHERN POLAR LIES ALONG 54S 120W...55S  
111W...55S 101W...EXITING AT 51S 90W. IT REFORMS AT 46S 66W...THEN  
ALONG 45S 54W...46S 43W...A 133KT MAXIMUM AT 39S 34W...EXITING AT  
36S 28W. THE NORTHERN POLAR LIES ALONG A 134KT MAXIMUM AT 50S  
119W...51S 109W...A 122KT MAXIMUM AT 50S 100W...EXITING AT 44S  
91W. IT REFORMS BETWEEN 34S 100W AND 30S 109W. ANOTHER BRANCH OF  
THE NORTHERN POLAR HAS ITS ENTRANCE AT 23S 109W...THEN ALONG 24S  
104W...32S 95W...35S 84W...A 131KT MAXIMUM AT 38S 72W...A 136KT  
MAXIMUM AT 40S 66W...41S 51W... 37S 41W...31S 31W...A 140KT  
MAXIMUM AT 35S 20W...EXITING AT 42S 07W. THE SUBTROPICAL JET LIES  
ALONG 18S 120W...15S 110W...EXITING AT 13S 102W. IT REFORMS AT 27S  
85W...ALONG 32S 77W...35S 66W...EXITING AT 33S 56W. THE  
SUBTROPICAL JET REFORMS TO THE EAST AT 21S 34W...ALONG 25S  
24W...30S 17W...36S 08W...AND 36S 02W. THE SUBEQUATORIAL JET LIES  
ALONG 15S 120W...12S 114W...EXITING AT 09S 108W.  
 
AT 500 HPA...SHORT WAVE TROUGH ALONG 90W TO 45S IS STREAMING  
TOWARDS THE DRAKE PASSAGE-TIERRA DEL FUEGO. NORTH OF THIS  
TROUGH...AN ELONGATED TROUGH EXTENDS FROM A LOW EAST OF THE  
MALVINAS/FALKLAND ISLANDS...ACROSS NORTHERN PATAGONIA...40S  
78W...TO 34S 90W. THIS IS FOCUSING SHORT WAVE ENERGY ACROSS  
NORTHERN PATAGONIA/LA PAMPA IN ARGENTINA...PROVIDING SUPPORT TO  
CONVECTION ACROSS THE BUENOS AIRES PROVINCE TO THE NORTH. FARTHER  
EAST...OVER THE CENTRAL SOUTH ATLANTIC...A TROUGH EXTENDS BETWEEN  
40W-20W AND TO THE SOUTH OF 26S.  
 
AT LOW LEVELS...THE SURFACE ANALYSIS SHOWS A PROGRESSIVE FRONT ON  
THE SOUTHERN STREAM THAT EXTENDS FROM AN OCCLUDED 958 HPA LOW AT  
60S 89W...ALONG A 964 HPA LOW AT 62S 86W...58S 79W...51S 82W...A  
1002 HPA LOW AT 48S 87W...44S 89W...AND 42S 94W. ANOTHER FRONT ON  
THE NORTHERN STREAM ORIGINATES ON AN OCCLUDED 986 HPA LOW AT 50S  
57W...THEN ALONG A 990 HPA LOW AT 49S 51W...47S 49W...A 998 HPA  
LOW AT 44S 51W...38S 54W...BUENOS AIRES-NORTHERN PATAGONIA...A  
1016 HPA LOW AT 38S 72W...31S 77W...27S 82W...24S 90W...TO A 1018  
HPA LOW AT 23S 94W. A RIDGE TO THE SOUTH CENTERS ON TWO 1029 HPA  
HIGHS...WITH ONE AT 36S 107W AND THE OTHER AT 33S 97W. ANOTHER  
FRONT OVER THE ATLANTIC EXTENDS FROM AN OCCLUDED 974 HPA LOW AT  
49S 31W...THEN ALONG A 978 HPA LOW AT 54S 28W...52S 25W...48S  
23W...A 984 HPA LOW AT 43S 22W...37S 18W...29S 25W...24S 35W...26S  
43W...TO RIO GRANDE DO SUL. AN OLD FRONT TO THE EAST AND NORTH  
EXTENDS ALONG A 1010 HPA LOW AT 34S 15W...26S 20W...22S 24W...19S  
29W...17S 36W...TO ESPIRITO SANTO/SOUTHERN MINAS GERAIS.  
 
OVIEDO...SHN (ARGENTINA)  
VANNUCCI...SMN (ARGENTINA)  
RIVAS...SENAMHI (PERU)  
DAVISON...WPC (USA)  

 
 
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