040  
FXSA20 KWBC 051418  
PMDSA  
 
SOUTH AMERICA SYNOPTIC DISCUSSION - INTERNATIONAL DESKS  
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD  
917 AM EST FRI JAN 05 2018  
 
GFS DATA AT FTPPRD.NCEP.NOAA.GOV/PUB/DATA/NCCF/COM/GFS/PROD/  
 
SYNOPSIS (VALID FROM JAN 05 AT 0000 UTC): THE 200 HPA ANALYSIS  
SHOWS A RIDGE EXTENDING WEST-TO-EAST ACROSS THE CONTINENT BETWEEN  
05S-30W WHILE CENTERING ON CLOSED HIGHS T 14S 66W AND 19S 48W. THE  
RIDGE UNDERCUTS A TROUGH TO THE NORTH THAT EXTENDS FROM A CLOSED  
LOW AT 07S 32W TO NORTHERN BRASIL/THE GUIANAS. THE RIDGE ALOFT IS  
VENTING SCATTERED DEEP CONVECTION OVER MATO  
GROSSO-TOCANTINS/GOIAS-BAHIA AND MINAS GERAIS IN BRASIL...WHILE  
THE TROUGH ALOFT IS ENHANCING CONVECTION ON THE NORTHEAST STATES.  
OTHER CONVECTION TO THE WEST CLUSTERED ACROSS CENTRAL/NORTHERN  
PERU TO ECUADOR.  
 
THE 250 HPA JET ANALYSIS SHOWS THE SOUTHERN POLAR JET WITH  
ENTRANCE AT 46S 120W...THEN ALONG 51S 106W...EXITING AT 54S 92W.  
IT REFORMS BETWEEN 53S 88W AND 44S 72W. IT REFORMS AT 43S  
68W...ALONG 45S 56W...EXITING AT 48S 41W. THE NORTHERN POLAR LIES  
ALONG 40S 120W...A 162KT MAXIMUM AT 46S 108W...49S 99W...A 147KT  
MAXIMUM AT 48S 90W...41S 77W...41S 61W...A 143KT MAXIMUM AT 42S  
51W...42S 31W...AND A 146KT MAXIMUM AT 46S 09W. THE SUBTROPICAL  
JET LIES ALONG 34S 120W...42S 110W...45S 98W...A 146KT MAXIMUM AT  
44S 89W...38S 79W...EXITING AT 35S 70W. IT REFORMS AT 28S  
47W...THEN ALONG 31S 39W...37S 24W...A 149KT MAXIMUM AT 42S  
12W...AND 42S 02E. AT 175 HPA THE SUBEQUATORIAL JET HAS A FINGER  
THAT EXTENDS BETWEEN 05S 98W AND 01N 90W. ANOTHER FINGER TO THE  
EAST EXTENDS BETWEEN 18S 36W AND 08S 45W.  
 
AT 500 HPA...A HIGH NEAR 30S 97W EXTENDS A RIDGE TO THE  
SOUTH-SOUTHEAST ALONG 50S 90W TO THE BELLINGSHAUSEN SEA. A TROUGH  
TO THE EAST EXTENDS BETWEEN 80W-50W TO 30S...FOCUSING SHORT WAVE  
ENERGY ACROSS SOUTHERN-CENTRAL CHILE INTO ARGENTINA. THIS IS  
PROVIDING DYNAMICAL SUPPORT TO ORGANIZED DEEP CONVECTION OVER THE  
BUENOS AIRES PROVINCE/ENTRE RIOS IN ARGENTINA.  
 
AT LOW LEVELS...A RIDGE ON THE NORTHERN STREAM DOMINATES THE FLOW  
OVER THE EASTERN PACIFIC WHILE ANCHORING ON TWO CLOSED HIGHS...A  
1025 HPA HIGH AT 32S 98W AND A 1023 HPA HIGH AT 38S 85W. EAST OF  
THIS AXIS...BROAD TROUGH OVER THE SOUTHERN CONE ANCHORS ON A 986  
HPA LOW AT 58S 69W. A POLAR FRONT EXTENDS FROM A 986 HPA LOW AT  
51S 66W...THEN ACROSS CENTRAL PATAGONIA TO TEMUCO IN SOUTHERN  
CHILE. THIS FAVORS SCATTERED CONVECTION ACROSS SOUTHERN PATAGONIA  
IN ARGENTINA. FARTHER EAST...A 982 HPA LOW AT 51S 46W EXTENDS A  
FRONT ALONG A 986 HPA LOW AT 49S 43W...45S 42W...A 1002 HPA LOW AT  
41S 45W...36S 49W...BUENOS AIRES PROVINCE-NEUQUEN-TO A 1014 HPA  
LOW AT 34S 73W. THIS FAVORS SCATTERED DEEP CONVECTION ACROSS  
CENTRAL PROVINCES IN ARGENTINA. ANOTHER FRONT TO THE EAST AND  
NORTH EXTENDS FROM A 994 HPA LOW AT 45S 11W...41S 10W...A 1014 HPA  
LOW AT 36S 22W...32S 24W...A 1014 HPA LOW AT 28S 35W...TO RIO DE  
JANEIRO. A RIDGE TO THE SOUTH CENTERS ON A 1019 HPA HIGH AT 32S  
37W.  
 
OVIEDO...SHN (ARGENTINA)  
POMIER...SENAMHI (BOLIVIA)  
DAVISON...WPC (USA)  

 
 
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