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South American Synoptic Discussion
 
(Caution: Version displayed is not the latest version. - Issued 1300Z Apr 16, 2014)
 
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Abbreviations and acronyms used in this product


SOUTH AMERICA SYNOPTIC DISCUSSION - INTERNATIONAL DESKS
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
900 AM EDT WED APR 16 2014

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

SYNOPSIS (VALID FROM 16 APRIL 00UTC): NORTH OVER THE CONTINENT THE
UPPER PATTERN CONTINUES TO EVOLVE...WITH SUBTROPICAL RIDGE NOW
CONFINING TO NORTHWEST SOUTH AMERICA WHILE CENTERING ON A CLOSED
HIGH NEAR 10S 62W. THE SUBEQUATORIAL RIDGE TO THE NORTH EXTENDS
ALONG 00N...ACROSS THE TROPICAL ATLANTIC TO THE
GUIANAS-VENEZUELA-COLOMBIA. IN THIS PATTERN...MOST ACTIVE
CONVECTION IS CLUSTERING ALONG THE NEAR EQUATORIAL TROUGH OVER
NORTHERN PARA-RORAIMA IN BRASIL TO THE SOUTHERN GUIANAS-AMAZONIA
IN VENEZUELA AND EASTERN PORTIONS OF COLOMBIA.
OTHERWISE...ISOLATED TO SCATTERED CONVECTION WAS BUILDING ACROSS
BRASIL TO THE NORTH OF 10S.

THE 250 HPA JET ANALYSIS SHOWS THE SOUTHERN POLAR WITH AXIS ALONG
A 130KT MAXIMUM AT 60S 121W...59S 114W...52S 99W...EXITING AT 47S
79W. IT THEN HAS A FINGER BETWEEN 48S 72W AND 55S 61W. THE
NORTHERN POLAR HAS ITS ENTRANCE AT 45S 115W...ALONG A 134KT
MAXIMUM AT 45S 100W...43S 89W...41S 79W...42S 70W...45S
59W...EXITING AT 46S 47W. THE SUBTROPICAL JET LIES ALONG 31S
120W...39S 113W...41S 105W...38S 93W...34S 85W...EXITING AT 33S
78W. IT REFORMS AT 35S 75W...ALONG 25S 64W...22S 54W...24S 47W...A
141KT MAXIMUM AT 34S 32W...36S 22W...EXITING AT 36S 12W.

AT 500 HPA...A BROAD TROUGH ON THE SOUTHERN STREAM DOMINATES FLOW
ACROSS THE SOUTHEAST PACIFIC TO THE SOUTHERN CONE OF SOUTH
AMERICA...AS IT EXTENDS BETWEEN 100W-50W AND TO THE SOUTH OF 30S.
SHORT WAVE PERTURBATIONS REVOLVE AROUND THIS AXIS...WITH ONE
LIFTING ACROSS 100W AS ANOTHER ENTERS SOUTHERN CHILE. A THIRDS TO
THE EAST IS PULLING ACROSS THE MALVINAS/FALKLAND ISLANDS. FARTHER
EAST...OVER THE SOUTH ATLANTIC...A SHORT WAVE TROUGH ON THE
NORTHERN STREAM EXTENDS FROM 40S 40W TO SOUTHERN BRASIL. A
WANING/LOW AMPLITUDE TROUGH TO THE EAST EXTENDS BETWEEN 35W-10W
AND TO THE SOUTH OF 44S.

THE SURFACE ANALYSIS SHOWS A BROAD TROUGH ON THE SOUTHERN STREAM
ENVELOPING AREA BETWEEN THE BELLINGSHAUSEN SEA AND THE SOUTHERN
CONE OF SOUTH AMERICA. POLAR FRONTS REVOLVE AROUND THIS AXIS WITH
ONE THAT EXTENDS FROM AN OCCLUDED 970 HPA LOW AT 53S 76W...ALONG A
966 HPA LOW AT 58S 77W...54S 65W...49S 66W...A 994 HPA LOW AT 47S
71W...40S 66W...37S 88W...AND 37S 92W. ANOTHER FRONT TO THE EAST
AND NORTH EXTENDS ALONG A 972 HPA LOW AT 58S 60W...52S 49W...A 996
HPA LOW AT 49S 52W...44S 53W...42S 58W...A 1002 HPA LOW AT 41S
64W...CENTRAL CUYO...WEAKENING ALONG 32S 77W. AN OLD BOUNDARY TO
THE EAST AND NORTH NOW EXTENDS ALONG A 1014 HPA LOW AT 39S
18W...34S 21W...31S 28W...25S 35W...RIO DE JANEIRO...18S 57W...TO
NORTHERN BOLIVIA. SCATTERED DEEP CONVECTION WAS BUILDING ACROSS
SOUTHEAST BRASIL. A POLAR RIDGE TO THE SOUTH CENTERS ON A 1021 HPA
HIGH AT 38S 36W.

ITA...SENAMHI (PERU)
FERNANDES...INMET (BRASIL)
DAVISON...WPC (USA)