944  
FXSA20 KWBC 011305  
PMDSA  
 
SOUTH AMERICA SYNOPTIC DISCUSSION - INTERNATIONAL DESKS  
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD  
905 AM EDT WED NOV 01 2017  
 
GFS DATA AT FTPPRD.NCEP.NOAA.GOV/PUB/DATA/NCCF/COM/GFS/PROD/  
 
SYNOPSIS (VALID FROM NOV 01 AT 0000 UTC): A 200 HPA HIGH NEAR 13S  
58W ANCHORS A RIDGE OVER NORTHERN SOUTH AMERICA. A TROUGH TO THE  
NORTHEAST OF THIS RIDGE EXTENDS ALONG 10S 30W TO 00N 40W. THE  
RIDGE ALOFT FAVORS A DIVERGENT PATTERN THAT IS VENTING DEEP  
CONVECTION OVER NORTHERN SOUTH AMERICA. MOST ACTIVE CLUSTERING  
ACROSS MINAS GERAIS/BAHIA...MATO GROSSO TO RONDONIA IN BRASIL...  
NORTHERN BOLIVIA AND THE SOUTHERN JUNGLE OF PERU.  
 
THE 250 HPA ANALYSIS SHOWS THE SOUTHERN POLAR WITH ENTRANCE AT 57S  
120W...THEN ALONG 62S 97W...58S 68W...EXITING AT 52S 52W. IT  
REFORMS AT 45S 40W..THEN ALONG A 147KT MAXIMUM AT 51S 32W...55S  
20W...AND 54S 06W. A FINGER OF THE SOUTHERN POLAR EXTENDS BETWEEN  
54S 116W AND 56S 95W. THE NORTHERN POLAR LIES ALONG 35S 120W...A  
136KT MAXIMUM AT 38S 114W...40S 106W...33S 89W...34S 76W...EXITING  
AT 36S 67W. IT REFORMS AT 40S 56W...ALONG 36S 48W...EXITING AT 36S  
43W. A BRANCH OF THE NORTHERN POLAR TO THE EAST HAS ITS ENTRANCE  
AT 36S 37W...ALONG 41S 33W...EXITING AT 47S 25W. THE SUBTROPICAL  
JET HAS ITS ENTRANCE AT 21S 93W...ALONG 24S 79W...25S 68W...26S  
56W...A 144KT MAXIMUM AT 29S 44W...32S 32W...35S 22W...A 121KT  
MAXIMUM AT 31S 15W...AND 25S 07W.  
 
AT 500 HPA...A SKEWED RIDGE EXTENDS TO THE SOUTHEAST FROM 25S  
110W...ALONG 40S 100W...TO 51S 81W. A TROUGH TO THE EAST EXTENDS  
BETWEEN 95W-70W TO 20S WHILE CENTERING ON A CLOSED LOW NEAR 43S  
81W. THE TROUGH IS FOCUSING SHORT WAVE ENERGY ACROSS  
CENTRAL-SOUTHERN CHILE TO ARGENTINA...WHERE IT PROVIDES DYNAMICAL  
SUPPORT TO DEEP CONVECTION. THE DEEP TROUGH OVER THE EASTERN  
PACIFIC IS INDUCING THE SOUTHWARD AMPLIFICATION OF A RIDGE ACROSS  
ARGENTINA. FARTHER EAST...OVER THE ATLANTIC...A SHORT WAVE TROUGH  
ON THE NORTHERN STREAM EXTENDS BETWEEN 53W-37W TO 37S. THIS IS  
PHASING WITH A SHORT WAVE TROUGH TO THE NORTHEAST.  
 
AT LOW LEVELS...AN ELONGATED FRONT ON THE SOUTHERN STREAM EXTENDS  
ALONG A 982 HPA LOW AT 64S 33W...58S 34W...55S 41W...A 988 HPA LOW  
AT 56S 49W...53S 56W...55S 63W...A 992 HPA LOW AT 58S 69W...57S  
76W...AND 59S 83W. A FRONT ON THE NORTHERN STREAM ORIGINATES ON AN  
OCCLUDED 998 HPA LOW AT 42S 80W...THEN ALONG A 1008 HPA LOW AT 46S  
76W...39S 70W...33S 75W...AND 30S 86W. THIS SUSTAINS SCATTERED  
RAINS BETWEEN CONCEPCION AND ISLA DE CHILOE. OVER THE ATLANTIC...A  
FRONT EXTENDS ALONG A 998 HPA LOW AT 43S 37W...36S 34W...27S  
38W...SAO PAULO...MATO GROSSO DO SUL TO CHACO PARAGUAYO. THIS IS  
PHASING WITH AN OLD BOUNDARY TO THE EAST AND NORTH THAT EXTENDS  
ALONG A 1002 HPA LOW AT 31S 32W...26S 32W...22S 36W...ESPIRITO  
SANTO/SOUTHERN MINAS GERAIS TO MATO GROSSO. ORGANIZED DEEP  
CONVECTION WAS CLUSTERING ALONG AND NORTH OF THIS BOUNDARY. A  
POLAR RIDGE TO THE SOUTH CENTERS ON A 1019 HPA HIGH AT 40S 59W AND  
A 1017 HPA HIGH AT 29S 49W.  
 
OVIEDO...SHIN (ARGENTINA)  
VANNUCCI...SMN (ARGENTINA)  
RIVAS...SENAMHI (PERU)  
DAVISON...WPC (USA)  

 
 
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