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South American Synoptic Discussion
 
(Caution: Version displayed is not the latest version. - Issued 1253Z Mar 23, 2015)
 
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SOUTH AMERICA SYNOPTIC DISCUSSION - INTERNATIONAL DESKS
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
853 AM EDT MON MAR 23 2015

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

SYNOPSIS (VALID FROM MARCH 23 AT 00UTC): CELL OF THE SUBTROPICAL
RIDGE EXTENDS SOUTH OVER THE CONTINENT BETWEEN 80W-55W TO 40S.
THIS FAVORS THE NORTHWARD AMPLIFICATION OF A TROUGH ALONG 50W TO
NORTHERN COAST OF BRASIL. THIS TROUGH IS INTERACTING WITH THE NEAR
EQUATORIAL TROUGH/ATLANTIC ITCZ...FAVORING A SURGE IN CONVECTION
ACROSS THE NORTHEAST STATES OF BRASIL INTO THE AMAZON RIVER DELTA
REGION. THE RIDGE ALOFT...MEANWHILE...IS VENTING DIURNAL
CONVECTION ACROSS NORTHWEST BRASIL INTO PERU.

THE 250 HPA JET ANALYSIS SHOWS THE SOUTHERN POLAR WITH ENTRANCE AT
50S 108W...THEN ALONG A 162KT MAXIMUM AT 62S 99W...AND 72S 87W.
THE NORTHERN POLAR HAS ITS ENTRANCE AT 31S 120W...THEN ALONG A
157KT MAXIMUM AT 40S 108W...A 153KT MAXIMUM AT 48S 101W...60S
89W...70S 72W...60S 66W...EXITING AT 52S 67W. THE SUBTROPICAL JET
TO THE NORTH HAS ITS ENTRANCE AT 45S 85W...THEN ALONG 36S
85W...EXITING AT 28S 88W. IT REFORMS AT 26S 86W...ALONG 30S
81W...33S 72W...29S 62W...EXITING AT 25S 55W.

AT MID LEVELS...BROAD TROUGH OVER THE EASTERN PACIFIC DOMINATES
AREA BETWEEN 130W-95W TO 25S. THIS IS PRESSING AGAINST A RIDGE TO
THE EAST...WITH THE LATTER EXTENDING FROM 30S 100W...ALONG 50S
80W...TO THE ANTARCTIC PENINSULA. BROAD TROUGH TO THE EAST
ENVELOPS AREA BETWEEN 65W-10W AND TO THE SOUTH OF 25S. SEVERAL
SHORT WAVE PERTURBATIONS REVOLVE AROUND THIS AXIS...LIFTING ACROSS
THE WEDDELL SEA-THE MALVINAS/FALKLAND ISLANDS INTO THE SOUTH
GEORGIA ISLANDS. OTHER SHORT WAVE PERTURBATIONS POPULATE THE
NORTHERN STREAM FLOW...WITH ONE MEANDERING OFF THE CENTRAL COAST
OF CHILE AS ANOTHER MIGRATES ACROSS THE SOUTHERN STATES OF BRASIL.

AT LOW LEVELS THE SURFACE ANALYSIS SHOWS A RIDGE ON THE SOUTHERN
STREAM THAT EXTENDS ACROSS SOUTHERN CHILE TO THE ANTARCTIC
PENINSULA...WHILE ANCHORING ON A CLOSED 1025 HPA HIGH AT 50S 80W.
EAST OF THIS RIDGE...AN OCCLUDED 1000 HPA LOW AT 59S 53W EXTENDS A
FRONT ALONG A 998 HPA LOW AT 57S 47W...A 1006 HPA LOW AT 53S
54W...50S 60W...TO SOUTHERN PATAGONIA/TIERRA DEL FUEGO...WHERE IT
FAVORS SCATTERED CONVECTION. AN ELONGATED FRONT TO THE NORTH LIES
ALONG A 1010 HPA LOW AT 40S 20W...36S 28W...A 1010 HPA LOW AT 33S
33W...28S 37W...A 1014 HPA LOW AT 25S 43W...22S 48W...SAO PAULO TO
CHACO PARAGUAYO. THIS FAVORS SCATTERED DEEP CONVECTION ACROSS
SOUTHEAST BRASIL. THE SACZ EXTENDS FROM NORTHERN SAO PAULO/RIO DE
JANEIRO...ACROSS MATO GROSSO-RONDONIA TO ACRE IN BRASIL.
MOISTURE/CONVECTION CLUSTERS ALONG THIS BOUNDARY.

ARREAGA...INAMHI (ECUADOR)
SCHNEIDER...INMET (BRASIL)
DAVISON...WPC (USA)