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FXSA20 KWBC 031317
PMDSA

SOUTH AMERICA SYNOPTIC DISCUSSION - INTERNATIONAL DESKS
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
916 AM EDT THU SEP 03 2015

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

SYNOPSIS (VALID FROM SEP 03 AT 0000 UTC): THE 200 HPA ANALYSIS
SHOWS A BROAD CELL OF THE SUBTROPICAL RIDGE ACROSS MID SECTIONS OF
SOUTH AMERICA...WITH CLOSED HIGH OVER CHACO PARAGUAYO CENTERED
SOUTH OF ITS CLIMATOLOGICAL POSITION. A CELL OF THE SUBEQUATORIAL
RIDGE TO THE NORTH IS BUILDING WEST ACROSS THE TROPICAL ATLANTIC
TO NORTHERN BRASIL...WHILE A WANING TUTT MEANDERS OVER WESTERN
BRASIL-PERU. THE TUTT ALOFT WAS ENHANCING DIURNAL CONVECTION
ACROSS AMAZONAS-ACRE IN WESTERN BRASIL TO PORTIONS OF PERU.

AT 250 HPA...THE SOUTHERN POLAR LIES ALONG 49S 120W...A 122KT
MAXIMUM AT 51S 110W...EXITING AT 52S 99W. IT REFORMS AT 53S 67W...
ALONG 51S 56W...EXITING AT 45S 50W. THE SOUTHERN POLAR HAS ANOTHER
BRANCH TO THE SOUTH WITH ENTRANCE AT 67S 69W...ALONG A 163KT
MAXIMUM AT 52S 50W...47S 39W...EXITING AT 52S 25W. THE NORTHERN
POLAR LIES ALONG A 134KT MAXIMUM AT 43S 120W...46S 109W...46S
94W...EXITING AT 46S 78W. IT REFORMS TO THE NORTH NEAR 29S
86W...ALONG 37S 72W...37S 58W...A 141KT MAXIMUM AT 34S 46W...28S
30W...A 122KT MAXIMUM AT 29S 19W...AND 39S 06W. THE SUBTROPICAL
JET HAS ITS ENTRANCE AT 12S 97W...ALONG 19S 88W...A 121KT MAXIMUM
AT 30S 77W...A 153KT MAXIMUM AT 35S 60W...A 145KT MAXIMUM AT 28S
40W...24S 29W...EXITING AT 23S 17W.

ANALYSIS AT 500 HPA SHOWS LOW AMPLITUDE RIDGE ACROSS THE SOUTHEAST
PACIFIC. SHORT WAVE PERTURBATIONS EMBED IN THIS FLOW...WITH A
TROUGH ALONG 95W TO 40S. ANOTHER ENTERED THE DRAKE PASSAGE-EXTREME
SOUTHERN PORTIONS OF CHILE. THESE THEN FEED INTO A BROAD/LOW
AMPLITUDE TROUGH OVER THE SOUTH ATLANTIC...AS THE LATTER ENVELOPS
AREA BETWEEN 60W-00W AND TO THE SOUTH OF 20S. A TROUGH ON THE
NORTHERN STREAM... MEANWHILE...MEANDERS BETWEEN 105W-80W AND TO
THE SOUTH OF 17S... WHILE ANCHORING ON A CLOSED LOW NEAR 25S 94W.

AT LOW LEVELS...A RIDGE OVER THE EASTERN PACIFIC CENTERS ON A 1035
HPA HIGH AT 40S 86W. PROGRESSIVE POLAR FRONT TO THE SOUTH EXTENDS
FROM AN OCCLUDED 982 HPA LOW AT 59S 75W...ALONG 58S 68W...A 998
HPA LOW AT 56S 67W... SOUTHERN PATAGONIA...47S 76W...51S 84W...A
1006 HPA LOW AT 52S 93W...47S 96W...44S 107W...TO A 1006 HPA LOW
AT 44S 116W. THIS SUSTAINS MODERATE RAINFALL ACROSS EXTREME
SOUTHERN PORTIONS OF CHILE-TIERRA DEL FUEGO. OVER THE SOUTH
ATLANTIC...BROAD TROUGH DOMINATES THE SOUTHERN STREAM FLOW. THIS
SUSTAINS AN ELONGATED POLAR FRONT THAT EXTENDS ALONG A 1010 HPA
LOW AT 34S 12W...29S 14W...22S 23W...VITORIA... SOUTHERN MINAS
GERAIS...MATO GROSSO DO SUL...A 1012 HPA LOW AT 24S 54W...TO CHACO
PARAGUAYO/ SOUTHEAST BOLIVIA. THIS FAVORS LIGHT RAINFALL ON THE
SOUTHEAST TO SOUTHERN COAST OF BRASIL. A RIDGE TO THE SOUTH OF
THIS FRONT ANCHORS ON TWO HIGHS...A 1025 HPA AT 39S 67W AND A 1021
HPA AT 30S 42W.

ROMERO...DMC (CHILE)
FARINA...DMH (PARAGUAY)
DAVISON...WPC (USA)
GALVEZ...WPC (USA)

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