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South American Synoptic Discussion
 
(Caution: Version displayed is not the latest version. - Issued 1428Z Feb 13, 2018)
 
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SOUTH AMERICA SYNOPTIC DISCUSSION - INTERNATIONAL DESKS
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
928 AM EST TUE FEB 13 2018

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

SYNOPSIS (VALID FROM FEB 13 AT 0000 UTC): AT 200 HPA...THE
SUBTROPICAL RIDGE/BOLIVIAN HIGH CENTERS OVER CENTRAL BOLIVIA WHILE
A CLOSED UPPER LOW CENTERS OVER PIAUI IN NORTHEASTERN BRASIL.
STRONGEST CONVECTI9ON IS OCCURRING IN THE WESTERN AMAZON FROM
WESTERN MATO GROSSO/RONDONIA INTO AMAZONAS/BRASIL...WHERE DEEP
LAYER MOISTURE LIES UNDER THE FAVORABLE UPPER DIVERGENT PATTERN
BETWEEN THE RIDGE AND THE TROUGH. STRONG BUT PULSING CONVECTION IS
ALSO OCCURRING NORTHERN BOLIVIA AND SOUTHERN PERU IN ASSOCIATION
WITH ENHANCED CONVERGENCE IN THE LEADING EDGE OF A SOUTHERLY WIND
SURGE AT LOW-LEVELS. ENHANCED CONVECTION IS ALSO OCCURRING IN
NORTHEASTERN BRAZIL IN ASSOCIATION WITH ENHANCED DESTABILIZATION
DUE TO WARM SEA SURFACE TEMPERATURES...AND A SOUTHERN DISPLACEMENT
OF THE ATLANTIC ITCZ.

THE UPPER JET ANALYSIS SHOWS THE SOUTHERN POLAR JET FORMING AT 47S
126W ALONG A 148KT MAXIMA AT 48S 119W...51S 105W...A 177KT MAXIMA
AT 55S 86W...54S 66W...EXITING AT 47S 55W. IT REFORMS AT 49S 45W
ALONG 51S 28W. THE NORTHERN POLAR JET EXTENDS A BRANCH ALONG 45S
119W...49S 104W...51S 87W...EXITING AT 47S 64W. ANOTHER BRANCH
FORMS AT 43S 83W ALONG 41S 71W...EXITING AT 32S 54W. IT REFORMS AT
34S 45W ALONG A 136KT MAXIMA AT 39S 39W...A 174KT MAXIMA AT 47S
14W. THE SUBTROPICAL JET FORMS A BRANCH AT 31S 70W ALONG 27S
54W...37S 33W...38S 10W/ IN TROPICAL SOUTH AMERICA...THE
INTENSIFICATION OF AN UPPER LOW IN NORTHEASTERN BRASIL HAS
STIMULATED THE DEVELOPMENT OF SUBEQUATORIAL JETS. ONE FORMS AT 17S
45W EXITING AT 12S 49W. ANOTHER EXTENDS AT 150 HPA FORMING AT 04S
48W ALONG 04S 40W...EXITING AT 07S 33W.

AT 500 HPA...A SOUTHERN STREAM TROUGH CENTERS ON A LOW AT 63S 95W.
THIS LIES TO THE SOUTH OF A TIGHT BELT OF NORTHWESTERLY WINDS THAT
EXTENDS FROM 45S 120W TO 50S 80W. TO THE EAST...A TROUGH EXTEND IN
THE SOUTH ATLANTIC ALONG 50W FROM 60S NORTH TO 45S. IN THE
NORTHERN STREAM...A WEAK SHORT WAVE TROUGH HAS CROSSED THE ANDES
FROM THE SOUTHWEST AND NOW EXTENDS FROM 45S 83W TO CUYO IN
ARGENTINA. A STRONGER AND LARGER TROUGH CENTERS ON A LOW AT 38S
45W AND EXTENDS AN AXIS TO THE NORTHWEST ACROSS SANTA CATARINA AND
MISIONES IN ARGENTINA. THIS TROUGH IS ENHANCING CYCLONIC VORTICITY
IN SOUTHERN BRASIL.

THE SURFACE ANALYSIS SHOWS A FRONT EXTENDING FROM THE
MALVINAS/FALKLANDS AT 52S 50E INTO A 1000 HPA LOW AT 54S 65W...51S
70W...48S 80W...47S 88W...44S 96W. A 1025 HPA HIGH CENTERS AT 36S
94W AND EXTENDS A RIDGE INTO AYSEN-CHILE. THIS EXTENDS ANOTHER
RIDGE INTO A 1017 HPA POLAR HIGH LOCATED AT 45S 63W. TO THE
NORTHEAST OF THIS HIGH...A FRONT EXTENDS ALONG A 998 HPA LOW AT
53S 48W...49S 48W...A 1010 HPA LOW AT 44S 55W...40S 59W...36S 66W.
A 1021 HPA POLAR HIGH CENTERS AT 35S 55W. A 1010 HPA OCCLUDED LOW
EXTENDS AT 37S 43W AN OCCLUDED FRONT ALONG 34S 42W...30S
44W...SOUTHERN SANTA CATARINA. ANOTHER FRONT EXTENDS FROM 33S 30W
TO A 1006 HPA LOW AT 36S 36W...29S 39W...25S 46W...24S 52W...24S
60W. A TROUGH EXTENDS ALONG 25S 45W...21S 52W...15S 59W. A WIND
SURGE IS PROPAGATING NORTHWESTWARD IN LOWER BOLIVIA WITH AXIS
ALONG 17S 60W...15S 63W...15S 69W.


POMIER...SENAMHI (BOLIVIA)
BALBINO...INMET (BRASIL)
GALVEZ...WPC (USA)