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South American Synoptic Discussion
 
(Latest Discussion - Issued 1507Z Feb 22, 2018)
 
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SOUTH AMERICA SYNOPTIC DISCUSSION - INTERNATIONAL DESKS
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
1007 AM EST THU FEB 22 2018

GFS DATA AT FTPPRD.NCEP.NOAA.GOV/PUB/DATA/NCCF/COM/GFS/PROD/

SYNOPSIS (VALID FROM FEB 22 AT 0000 UTC): THE 200 HPA ANALYSIS
SHOWS A CELL OF THE SUBTROPICAL RIDGE ENVELOPING CONTINENTAL AREA
TO THE NORTH OF 25S WHILE CENTERING ON A CLOSED HIGH OVER BRASIL
NEAR 14S 54W. THIS IS VENTING DEEP CONVECTION ACROSS NORTHERN
SOUTH AMERICA...WITH MOST INTENSE CLUSTERING OVER
PARA-TOCANTINS/GOIAS IN BRASIL AND ACROSS NORTHERN
BOLIVIA-ACRE/RONDONIA IN BRASIL.

THE 250 HPA JET ANALYSIS SHOWS THE SOUTHERN POLAR WITH AXIS ALONG
49S 120W...51S 103W...EXITING AT 58S 93W. IT REFORMS AT 62S
89W...ALONG 58S 76W...EXITING AT 52S 69W. A FINGER TO THE EAST
EXTENDS BETWEEN 52S 62W AND 59S 52W. THE SOUTHERN POLAR REFORMS AT
67S 54W...ALONG 63S 40W...EXITING AT 57S 31W. THE NORTHERN POLAR
LIES ALONG 45S 120W...A 154KT MAXIMUM AT 47S 110W...A 132KT
MAXIMUM AT 47S 97W...EXITING AT 47S 92W. IT REFORMS AT 42S
84W...CROSSING 45S 75W...A 132KT MAXIMUM AT 43S 67W...EXITING AT
45S 60W. IT REFORMS AT 42S 46W...ALONG A 128KT MAXIMUM AT 46S
38W...A 165KT MAXIMUM AT 48S 23W...AND 43S 10W. THE SUBTROPICAL
JET HAS ITS ENTRANCE AT 34S 94W...ALONG 35S 90W...39S 80W...41S
68W...EXITING AT 40S 60W. A FINGER TO THE NORTH HAS ITS ENTRANCE
AT 35S 58W... CROSSING 30S 55W...EXITING AT 32S 49W. ANOTHER
FINGER EXTENDS BETWEEN 26S 60W AND 28S 48W.

AT 500 HPA...BROAD TROUGH DOMINATES THE FLOW OVER THE SOUTHEAST
PACIFIC...ENVELOPING AREA TO THE SOUTH OF 30S. PROGRESSIVE
PERTURBATIONS EMBED IN THIS FLOW...WITH ONE EXTENDING ALONG 120W
TO 40S...WHILE ANOTHER IS PULLING ACROSS 90W. A THIRD EXTENDS FROM
THE BELLINGSHAUSEN SEA TO THE SOUTHERN CONE OF SOUTH AMERICA.
DOWNSTREAM FROM THE LATTER...A SKEWED RIDGE EXTENDS FROM CENTRAL
ARGENTINA...ALONG 50S 50W...60S 50W...TO THE WEDDELL SEA. A SHORT
WAVE TROUGH ON THE NORTHERN STREAM...MEANWHILE...EXTENDS FROM THE
WESTERN ATLANTIC TO THE SOUTHERN STATES OF BRASIL-MESOPOTAMIA
VALLEY IN ARGENTINA. THIS EVOLVED INTO A CLOSED LOW OVER URUGUAY
NEAR 33S 54W.

AT LOW LEVELS...BROAD TROUGH OVER THE SOUTHEAST PACIFIC EXTENDS A
FRONT ALONG A 954 HPA LOW AT 61S 106W...THEN ALONG A 962 HPA LOW
AT 61S 98W...55S 92W...48S 96W...46S 101W...A 994 HPA LOW AT 48S
109W...45S 110W...44S 111W...A 998 HPA LOW AT 44S 116W...40S
118W...AND ALONG 20S 121W. ANOTHER FRONT TO THE EAST EXTENDS FROM
AN OCCLUDED 966 HPA LOW AT 63S 69W...A 974 HPA LOW AT 63S
65W...61S 58W...57S 58W...55S 60W...A 994 HPA LOW AT 54S 63W...49S
59W...NRN PATAGONIA/LA PAMPA IN ARGENTINA...36S 77W...36S 83W...A
1018 HPA LOW AT 35S 89W...32S 91W...AND 30S 97W. FARTHER
NORTH...AN OCCLUDED 1006 HPA LOW AT 31S 52W EXTENDS A FRONT ALONG
A 1006 HPA LOW AT 33S 53W...RIO GRANDE DO SUL TO PARAGUAY. A RIDGE
TO THE SOUTH CENTERS ON A 1013 HPA HIGH AT 34S 62W. EAST OF THIS
FRONT...ANOTHER BOUNDARY EXTENDS FROM AN OCCLUDED 998 HPA LOW AT
36S 42W...ALONG A 1000 HPA LOW AT 41S 38W...39S 37W...37S 38W...A
998 HPA LOW AT 35S 41W...31S 39W...27S 40W...A 1008 HPA LOW AT 24S
42W...21S 44W...MATO GROSSO DO SUL TO NORTHERN BOLIVIA. CONVECTION
WAS CLUSTERING ALONG AND NORTH OF THIS BOUNDARY ACROSS BRASIL TO
BOLIVIA. 

POMIER...SENAMHI (BOLIVIA)
BALBINO...INMET (BRASIL)
DAVISON/GALVEZ...WPC (USA)