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South American Synoptic Discussion
 
(Caution: Version displayed is not the latest version. - Issued 1618Z Dec 06, 2017)
 
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SOUTH AMERICA SYNOPTIC DISCUSSION - INTERNATIONAL DESKS
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
1118 AM EST WED DEC 06 2017

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

SYNOPSIS (VALID FROM DEC 06 AT 0000 UTC): AT 200 HPA...BROAD CELL
OF THE SUBTROPICAL RIDGE ENVELOPS CONTINENTAL AREA TO THE NORTH OF
36S WHILE CENTERING ON A CLOSED HIGH AT 18S 56W. NORTH OF THIS
AXIS...AN ELONGATED TROUGH EXTENDS ALONG 05S 30W...NORTH COAST OF
BRASIL TO THE GUIANAS. THE UPPER TROUGH SUSTAINS A
CONVERGENT/SUBSIDENT PATTERN THAT IS INHIBITING ORGANIZED DEEP
CONVECTION ACROSS PARA-NORTHEAST BRASIL.

THE 250 HPA JET ANALYSIS SHOWS THE SOUTHERN POLAR WITH AXIS ALONG
53S 120W...57S 103W...A 139KT MAXIMUM AT 56S 89W...53S 73W...55S
50W...A 120KT MAXIMUM AT 52S 44W...46S 31W...EXITING AT 44S 22W.
THE NORTHERN POLAR LIES ALONG 47S 120W...54S 98W...EXITING AT 49S
78W. IT REFORMS AT 48S 71W...ALONG 50S 55W...EXITING AT 45S 43W.

AT 500 HPA...A LOW AMPLITUDE RIDGE EXTENDS BETWEEN 110W-90W TO 64S
WHILE ORIGINATING ON A CLOSED HIGH AT 33S 106W. EAST OF THIS
RIDGE...SHORT WAVE TROUGH ON THE SOUTHERN STREAM FLOW EXTENDS FROM
THE DRAKE PASSAGE TO SOUTHERN CHILE/PATAGONIA IN ARGENTINA.
ANOTHER SHORT WAVE TROUGH TO THE NORTH...MEANWHILE...EXTENDS FROM
38S 75W TO 22S 85W. FARTHER EAST...BROAD TROUGH DOMINATES THE FLOW
OVER THE SOUTH ATLANTIC AS IT EXTENDS BETWEEN 40W-00W AND TO THE
SOUTH OF 20S.

AT LOW LEVELS...A RIDGE DOMINATES THE NORTHERN STREAM FLOW OVER
THE EASTERN PACIFIC WHILE CENTERING ON A 1031 HPA HIGH AT 38S
100W. IN A TIGHT BELT OF WESTERLIES...PROGRESSIVE FRONTS ARE
STREAMING TO THE SOUTH...WITH ONE EXTENDING FROM AN OCCLUDED 978
HPA LOW AT 61S 65W...A 982 HPA LOW AT 59S 60W...54S 60W...SRN
PATAGONIA...A 1014 HPA LOW AT 50S 79W...45S 81W...43S 88W...TO 46S
94W. ANOTHER FRONT TO THE EAST EXTENDS FROM A 982 HPA LOW AT 50S
30W...ALONG A 986 HPA LOW AT 48S 26W...43S 30W...41S 35W...41S
42W...44S 49W...47S 55W...A 1002 HPA LOW AT 51S 64W...TO CENTRAL
PATAGONIA. ALSO OVER THE ATLANTIC...A RIDGE ON THE NORTHERN STREAM
CENTERS ON A 1021 HPA HIGH AT 34S 40W. AN ELONGATED FRONT TO THE
NORTH LIES ALONG 37S 11W...34S 17W...29S 25W...26S
35W...PARANA-CORRIENTES...TO CORDOBA IN ARGENTINA. AN OLD BOUNDARY
TO THE EAST AND NORTH OF THE LATTER EXTENDS ALONG A 1016 HPA LOW
AT 35S 10W...30S 13W...29S 18W...A 1014 HPA LOW AT 29S 24W...25S
25W...24S 30W...A 1014 HPA LOW AT 25S 35W...TO ESPIRITO SANTO.

OVIEDO...SHN (ARGENTINA)
POMIER...SENAMHI (BOLIVIA)
RIVAS...SENAMHI (PERU)
DAVISON...WPC (USA)