619  
FXSA20 KWBC 021431  
PMDSA  
 
SOUTH AMERICA SYNOPTIC DISCUSSION - INTERNATIONAL DESKS  
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD  
930 AM EST FRI FEB 02 2018  
 
GFS DATA AT FTPPRD.NCEP.NOAA.GOV/PUB/DATA/NCCF/COM/GFS/PROD/  
 
SYNOPSIS (VALID FROM FEB 02 AT 0000 UTC): AT 200 HPA...BROAD RIDGE  
DOMINATES THE CONTINENT...WHILE ANCHORING ON A CLOSED HIGH AT 20S  
60W. THE RIDGE ALOFT IS VENTING ORGANIZED DEEP CONVECTION ALONG  
THE SACZ OVER BRASIL...AS IT EXTENDS ACROSS ESPIRITO SANTO-MINAS  
GERAIS-MATO GROSSO TO BOLIVIA. A TROUGH TO THE NORTH...CAVADO DO  
NORDESTE...EXTENDS ACROSS THE NORTHERN STATES OF BRASIL TO THE  
GUIANAS. THIS IS INTERACTING WITH THE ATLANTIC ITCZ IN SUPPORT OF  
ORGANIZED DEEP CONVECTION. A NEGATIVELY TILTED TROUGH TO THE  
WEST...MEANWHILE...EXTENDS ALONG 20S 90W...10S 80W TO NORTHERN  
PERU. THIS IS VENTING DEEP CONVECTION ON THE CENTRAL/SOUTHERN  
SIERRA AND JUNGLE OF PERU.  
 
AT 200 HPA...THE SOUTHERN POLAR LIES ALONG 49S 120W...A 137KT  
MAXIMUM AT 49S 110W...A 157KT MAXIMUM AT 52S 99W...A 186KT MAXIMUM  
AT 57S 83W...A 170KT MAXIMUM AT 59S 66W...56S 54W...EXITING AT 51S  
47W. THE NORTHERN POLAR LIES ALONG 46S 120W...A 131KT MAXIMUM AT  
45S 115W...48S 102W...A 149KT MAXIMUM AT 53S 87W...A 137KT MAXIMUM  
AT 56S 70W...51S 56W...45S 51W...EXITING AT 40S 48W. IT REFORMS AT  
41S 84W...THEN ALONG 44S 32W...46S 23W...50S 12W...AND 50S 02W. A  
FINGER OF THE SUBTROPICAL JET EXTENDS BETWEEN 46S 94W AND 51S 71W.  
ANOTHER FINGER EXTENDS BETWEEN 47S 61W...EXITING 37S 50W. A BRANCH  
OF THE SUBTROPICAL JET TO THE NORTH EXTENDS FROM 11S 74W...THEN  
ALONG 17S 79W...25S 82W...35S 73W...33S 58W...RIO GRANDE DO  
SUL...TO 24S 38W. THE SUBEQUATORIAL JET...AT 150 HPA...LIES ALONG  
10S 117W...10S 107W...10S 92W...EXITING AT 04S 80W. A FINGER TO  
THE NORTH EXTENDS ALONG 01S 109W...EXITING AT 01S 95W.  
 
AT 500 HPA...A BROAD MID LEVEL TROUGH EXTENDS OVER THE SOUTHEAST  
PACIFIC. THIS EXTENDS BETWEEN 140W-80W AND TO THE SOUTH OF  
40S...WHILE CENTERING ON TWO LOWS NEAR 65SD 110W AND 67S 94W. THE  
TROUGH IS FOCUSING SHORT WAVE ENERGY ACROSS EXTREME SOUTHERN  
CHILE-TIERRA DEL FUEGO TO THE DRAKE PASSAGE. THIS IS ALSO PRESSING  
AGAINST A MID LEVEL RIDGE THAT EXTENDS SOUTH ACROSS ARGENTINA TO  
THE DRAKE PASSAGE. BROAD TROUGH TO THE EAST EXTENDS BETWEEN  
60W-15W AND TO THE SOUTH OF 35S. THE RIDGE TO THE WEST IS STEERING  
A SHORT WAVE PERTURBATION AROUND THE BROAD TROUGH TO THE  
EAST...WITH VORTEX EXTENDING FROM 50S 49W TO THE BUENOS AIRES  
PROVINCE.  
 
AT LOW LEVELS...OVER THE PACIFIC...A RIDGE ON THE NORTHERN STREAM  
CENTERS ON A 1023 HPA HIGH AT 33S 113W AND A 1025 HPA HIGH AT 35S  
87W. BROAD TROUGH LIES TO THE SOUTH...CENTERING ON AN OCCLUDED 954  
HPA LOW AT 67S 89W. POLAR FRONTS REVOLVE AROUND THIS AXIS...WITH  
ONE EXTENDING ALONG A 978 HPA LOW AT 58S 65W...55S 68W...54S  
72W...A 982 HPA LOW AT 56S 78W...53S 84W...50S 89W...A 998 HPA LOW  
AT 50S 93W...46S 97W...43S 103W...A 1010 HPA LOW AT 42S 108W...AND  
38S 114W. OVER THE SOUTH ATLANTIC...BROAD TROUGH CENTERS ON AN  
OCCLUDED 962 HPA LOW AT 59S 38W. POLAR FRONTS LIE TO THE  
NORTH...WITH ONE EXTENDING FROM AN OCCLUDED 990 HPA LOW AT 48S  
48W...A 990 HPA LOW AT 49S 46W...43S 49W...42S 55W...TO 44S 59W.  
THIS IS INTERACTING WITH AN OLD BOUNDARY TO THE NORTH THAT EXTENDS  
ALONG A 998 HPA LOW AT 43S 45W...38S 50W...BUENOS AIRES PROVINCE  
TO LA PAMPA IN ARGENTINA. A RIDGE TO THE SOUTH CENTERS ON A 1015  
HPA HIGH AT 39S 62W. AN OLD FRONT TO THE  
NORTH...MEANWHILE...EXTENDS ALONG A 1006 HPA LOW AT 32S 29W...33S  
28W...32S 31W...A 1008 HPA LOW AT 31S 32W...27S 32W...25S  
35W...SAO PAULO TO SOUTHEAST PARAGUAY. A RIDGE TO THE SOUTH  
CENTERS ON A 1015 HPA HIGH AT 32S 45W.  
 
BALBINO...INMET (BRASIL)  
POMIER...SENAMHI (BOLIVIA)  
DAVISON/GALVEZ...WPC (USA)  

 
 
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