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South American Synoptic Discussion
 
(Caution: Version displayed is not the latest version. - Issued 1428Z Feb 23, 2015)
 
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SOUTH AMERICA SYNOPTIC DISCUSSION - INTERNATIONAL DESKS
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
928 AM EST MON FEB 23 2015

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

SYNOPSIS (VALID FROM FEBRUARY 23 AT 00UTC): THE 200 HPA ANALYSIS
SHOWS THE SUBTROPICAL RIDGE OVER THE CONTINENT TO THE NORTH OF 30S
AND WEST OF 50W...WITH AXIS ANCHORING ON A CLOSED HIGH OVER THE
ALTIPLANO OF BOLIVIA. A TROUGH TO THE EAST EXTENDS ACROSS THE
NORTHEAST STATES OF BRASIL...WITH AXIS ALONG 20S 40W...A LOW AT
10S 49W TO THE GUIANAS. THIS IS ENHANCING CONVECTION ACROSS
NORTHEAST OF BRASIL AND WESTWARD ALONG THE NEAR EQUATORIAL TROUGH.

AT 250 HPA...THE NORTHERN POLAR HAS ITS ENTRANCE AT 46S
120W...THEN ALONG 49S 104W...A 145KT MAXIMUM AT 50S 90W...A 150KT
MAXIMUM AT 52S 74W...A 130KT MAXIMUM AT 50S 64W...EXITING AT 47S
60W. THE SUBTROPICAL JET HAS ITS ENTRANCE AT 38S 117W...THEN ALONG
44S 99W...47S 76W...EXITING AT 43S 65W. IT HAS A FINGER TO THE
NORTH WITH ENTRANCE AT 36S 79W...ALONG 33S 91W...EXITING AT 32S
99W. THE JET REFORMS AT 21S 93W...ALONG 25S 86W...31S
74W...EXITING AT 30S 59W. THE SUBTROPICAL JET HAS ANOTHER BRANCH
TO THE EAST WITH ENTRANCE AT 32S 51W...THEN ALONG 36S 41W...A
133KT MAXIMUM AT 40S 24W...40S 14W...EXITING AT 42S 02W.

AT 500 HPA...PROGRESSIVE SHORT WAVE PERTURBATIONS ARE STREAMING
ACROSS THE SOUTH PACIFIC...WITH A STRONG PERTURBATION PULLING
ACROSS 98W AS ANOTHER ENTERS THE DRAKE PASSAGE. A THIRD/HIGHER
AMPLITUDE TROUGH TO THE EAST EXTENDS NORTH FROM THE
MALVINAS/FALKLAND ISLANDS TO THE BUENOS AIRES PROVINCE. AN
EAST-TO-WEST RIDGE TO THE NORTH EXTENDS ALONG 30S 20W...SOUTHEAST
BRASIL-PARAGUAY TO SOUTHERN BOLIVIA. A SHORT WAVE TROUGH IS
STREAMING TO THE SOUTH OF THIS AXIS...FOCUSING SHORT WAVE ENERGY
ACROSS THE SOUTHERN STATES OF BRASIL WHERE IT FAVORS SCATTERED
CONVECTION. FURTHERMORE...A CUT OFF LOW ON THE NORTHERN STREAM
LIES OVER THE EASTERN PACIFIC NEAR 26S 87W.

THE SURFACE ANALYSIS SHOWS A BROAD TROUGH ON THE SOUTHERN
STREAM...ANCHORING ON AN OCCLUDED 974 HPA LOW AT 58S 77W. A POLAR
FRONT EXTENDS FROM THIS AXIS ALONG A 978 HPA LOW AT 59S 69W...A
984 HPA LOW AT 58S 62W...55S 62W...A 988 HPA LOW AT 53S
67W...CENTRAL PATAGONIA-PUERTO MONTT CHILE...A 1006 HPA LOW AT 49S
79W...45S 81W...A 1006 HPA LOW AT 46S 89W...41S 95W...AND 38S
104W. THIS SUSTAINS SCATTERED RAINFALL ACROSS EXTREME SOUTHERN
PORTIONS OF CHILE. ANOTHER FRONT TO THE NORTH LIES ALONG A 1002
HPA LOW AT 51S 47W...44S 52W...TO LA PAMPA IN ARGENTINA...WHERE IT
FAVORS ISOLATED CONVECTION. A RIDGE TO THE NORTH CENTERS ON A 1025
HPA HIGH AT 40S 30W. AN OLD/ELONGATED FRONT BOUNDS THE NORTHERN
PERIPHERY OF THIS RIDGE...AS IT EXTENDS ALONG A 1018 HPA LOW AT
37S 17W...33S 23W...32S 31W...A 1018 HPA LOW AT 34S 39W...30S
45W...RIO GRANDE DO SUL/NORTHERN URUGUAY.

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