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South American Synoptic Discussion
 
(Caution: Version displayed is not the latest version. - Issued 1447Z Feb 20, 2015)
 
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SOUTH AMERICA SYNOPTIC DISCUSSION - INTERNATIONAL DESKS
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
947 AM EST FRI FEB 20 2015

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

SYNOPSIS (VALID FROM FEBRUARY 20 AT 00UTC): THE 200 HPA ANALYSIS
SHOWS THE BOLIVIAN HIGH WITH CLOSED CIRCULATION OVER RONDONIA IN
BRASIL...AND WITH AXIS WEST ACROSS NORTHERN BOLIVIA-CENTRAL PERU
TO THE EASTERN PACIFIC ALONG 10S 90W. THE HIGH ALSO RIDGES TO THE
SOUTHEAST ALONG 20S 50W TO 30S 40W. A TROUGH TO THE EAST EXTENDS
ACROSS NORTHEAST STATES OF BRASIL WHILE ORIGINATING ON A CLOSED
LOW AT 13S 34W. BEST DIVERGENCE ALOFT REMAINS BETWEEN THE RIDGE TO
THE WEST AND THE TROUGH TO THE EAST...ENHANCING CONVECTION ACROSS
CENTRAL-NORTHEAST BRASIL. FURTHERMORE...THE RIDGE ALOFT IS ALSO
VENTING DEEP CONVECTION ACROSS PERU AND PORTIONS OF BOLIVIA.

AT 250 HPA...THE JET ANALYSIS SHOWS THE SOUTHERN POLAR WITH AXIS
ALONG A 130KT MAXIMUM AT 58S 120W...EXITING AT 61S 91W. IT REFORMS
AT 66S 66W...ALONG A 125KT MAXIMUM AT 57S 60W...EXITING AT 54S
57W. THE NORTHERN POLAR LIES ALONG 53S 119W...50S 98W...EXITING AT
59S 75W. IT REFORMS AT 60S 69W...ALONG 54S 62W...EXITING AT 48S
60W. IT REFORMS AT 41S 55W...ALONG 148KT MAXIMUM AT 46S 49W...A
179KT MAXIMUM AT 51S 39W...A 166KT MAXIMUM AT 57S 29W...57S
10W...49S 02W...AND 42S 00W. THE SUBTROPICAL JET HAS ITS ENTRANCE
AT 44S 71W...ALONG 40S 72W...EXITING AT 35S 74W. IT REFORMS AT 24S
80W...ALONG 25S 68W...30S 57W...EXITING AT 38S 46W. THE
SUBTROPICAL HAS A WEAKER BRANCH REVOLVING AROUND THE TUTT LOW TO
THE NORTH...WITH ENTRANCE AT 17S 38W...ALONG 12S 38W...EXITING AT
08S 33W.

AT 500 HPA...WANING RIDGE EXTENDS OVER THE EASTERN PACIFIC...WITH
AXIS EXTENDING FROM A CLOSED HIGH NEAR 36S 109W...ALONG 50S
80W...DRAKE PASSAGE TO THE ANTARCTIC PENINSULA. A TROUGH ON THE
SOUTHERN STREAM IS PRESSING AGAINST THIS AXIS...AS IT EXTENDS
ALONG 70S 90W...60S 85W...50S 97W...TO 45S 100W. A HIGHER
AMPLITUDE TROUGH TO THE EAST EXTENDS FROM A LOW NEAR 65S
40W...ALONG 40S 65W...37S 70W...TO 23S 83W. THIS IS FOCUSING SHORT
WAVE ENERGY ACROSS CENTRAL/NORTHERN PORTIONS OF CHILE INTO
ARGENTINA...TRIGGERING LEESIDE CONVECTION ACROSS MENDOZA-NORTHWEST
PROVINCES.

AT LOW LEVELS...SURFACE ANALYSIS SHOWS A BROAD RIDGE ON THE
NORTHERN STREAM THAT ANCHORS ON A 1033 HPA HIGH AT 37S 106W. AN
ELONGATED FRONT TO THE SOUTH EXTENDS ALONG A 990 HPA LOW AT 61S
72W...54S 77W...50S 86W...A 1026 HPA LOW AT 48S 91W...A 1030 HPA
LOW AT 45S 99W AND 42S 106W. ANOTHER FRONT EXTENDS FROM A 1008 HPA
LOW AT 48S 51W...44S 56W...TO 40S 64W. AN ELONGATED POLAR FRONT TO
THE EAST EXTENDS ALONG A 996 HPA LOW AT 53S 32W...46S 37W...42S
43W...A 1006 HPA LOW AT 39S 47W...33S 50W... SOUTHERN BRASIL TO
NORTHERN PROVINCES IN ARGENTINA. A POLAR RIDGE TO THE SOUTH
CENTERS ON A 1017 HPA HIGH AT 39S 59W.

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