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South American Synoptic Discussion
 
(Caution: Version displayed is not the latest version. - Issued 1324Z Apr 13, 2015)
 
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SOUTH AMERICA SYNOPTIC DISCUSSION - INTERNATIONAL DESKS
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
924 AM EDT MON APR 13 2015

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

SYNOPSIS (VALID FROM APRIL 13 AT 00UTC): AT 200 HPA...THE
SUBTROPICAL RIDGE EXTENDS ACROSS THE CONTINENT TO THE NORTH OF 20S
WHILE CENTERING ON A CLOSED HIGH AT 10S 50W. THE SUBEQUATORIAL
RIDGE TO THE NORTH EXTENDS WEST ACROSS THE GUIANAS-VENEZUELA TO
COLOMBIA WHILE CENTERING ON A CLOSED HIGH AT 01S 36W. THESE ARE
VENTING DEEP CONVECTION OVER THE CONTINENT TO THE NORTH OF
15S...WITH MOST INTENSE CLUSTERING OVER EQUATORIAL SOUTH AMERICA.

THE 250 HPA JET ANALYSIS SHOWS THE SOUTHERN POLAR JET ALONG 62S
120W...62S 103W...53S 95W...43S 84W...A 135KT MAXIMA AT 48S
72W...57S 59W...EXITING AT 53S 35W. THE NORTHERN POLAR JET FORMS
AT 45S 95W ALONG 40S 82W...A 123KT MAXIMA AT 42S 73W...47S
66W...EXITING AT 51S 55W. IT REFORMS AT 47S 44W ALONG 38S
42W...EXITING AT 33S 36W. THE SUBTROPICAL JET FORMS AT 43S 52W
EXITING AT 31S 44W. ANOTHER BRANCH FORMS AT 30S 57W ALONG 26S
46W...EXITING AT 22S 33W.

AT 500 HPA...A RIDGE EXTENDS SOUTH ALONG 105W TO 70S. EAST OF THIS
RIDGE...A BROAD TROUGH EXTENDS OVER THE FAR EASTERN PACIFIC INTO
THE SOUTHERN CONE OF SOUTH AMERICA...FOCUSING SHORT WAVE ENERGY
INTO SOUTHERN PORTIONS OF CHILE-TIERRA DEL FUEGO AND PATAGONIA IN
ARGENTINA. THIS IS PRESSING AGAINST A RIDGE TO THE EAST...AS THE
LATTER EXTENDS FROM NORTHERN ARGENTINA...ACROSS BUENOS AIRES
PROVINCE...47S 50W TO THE SOUTH GEORGIA ISLANDS. DOWNSTREAM FROM
THIS AXIS...A TROUGH ON THE NORTHERN STREAM LIES OVER THE
ATLANTIC...ENVELOPING AREA BETWEEN 50W-20W AND TO THE SOUTH OF
18S. A CLOSED LOW NEAR 43S 37W ANCHORS THIS AXIS.

THE SURFACE ANALYSIS SHOWS A 988 HPA OCCLUDED LOW AT 51S 81W. TO
THE EAST...A 994 HPA LOW AT 58S 68W EXTENDS A FRONT INTO A 994 HPA
LOW AT 50S 65...AND A WEAKENING TAIL AT 44S 71W. A 994 HPA LOW AT
55S 61W EXTENDS A FRONT INTO 51S 58W...A 998 HPA LOW AT 47S
65W...40S 68W...35S 78W. RAINFALL WAS OCCURRING SOUTH OF
CONCEPCION IN CHILE AND IN PARTS OF WESTERN ARGENTINA. A 1017 HPA
HIGH CENTERS AT 44S 51W...AND ANOTHER 1017 HPA HIGH CENTERS AT 34S
53W. A 1010 HPA LOW AT 30S 33W EXTENDS A FRONT INTO 27S 39W...26S
47W...29S 53W.

CALLE...UNALM (PERU)
CHARPENTIER...DMC (CHILE)
SCHNEIDER...INMET (BRASIL)
DAVISON...WPC (USA)
GALVEZ...WPC (USA)