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South American Synoptic Discussion
 
(Caution: Version displayed is not the latest version. - Issued 1357Z May 17, 2018)
 
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SOUTH AMERICA SYNOPTIC DISCUSSION - INTERNATIONAL DESKS
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
957 AM EDT THU MAY 17 2018

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

SYNOPSIS (VALID FROM MAY 17 AT 0000 UTC): AT 200 HPA...A HIGH OVER
NORTHEAST BRASIL ANCHORS A RIDGE OVER NORTHERN SOUTH
AMERICA...WITH AXIS CONFINING TO AREA NORTH OF 10S. THIS IS
VENTING LATE AFTERNOON/EVENING CONVECTION OVER THE CONTINENT TO
THE NORTH OF 13S AND WEST OF 50W...WITH MOST ACTIVE CLUSTERING
OVER AMAZONAS-PARA AND ACRE IN BRASIL AND THE JUNGLE OF PERU.

THE 250 HPA JET ANALYSIS SHOWS THE SOUTHERN POLAR JET FORMING AT
41S 126W ALONG 41S 112W...EXITING AT 46S 99W. ANOTHER BRANCH FORMS
AT 67S 55W ALONG 60S 56W...A 111KT MAXIMA AT 56S 55W...48S
52W...41S 44W...42S 32W...A 119KT MAXIMA AT 45S 23W...49S 16W. THE
NORTHERN POLAR JET EXTENDS ALONG A 141KT MAXIMA AT 32S 120W...33S
115W...A 137KT MAXIMA AT 34S 112W...35S 105W...36S 100W...A 131KT
MAXIMA AT 36S 96W...34S 85W...34S 75W...EXITING AT 39S 68W. IT
REFORMS AT 46S 70W ALONG 43S 61W...A 124KT MAXIMA AT 37S 54W...34S
45W...35S 36W...A 154KT MAXIMA AT 38S 30W...A 161KT MAXIMA AT 44S
20W. THE SUBTROPICAL JET EXTENDS ALONG 27S 120W...30S 108W...31S
93W...29S 78W...31S 70W...32S 62W...EXITING AT 29S 55W. IT REFORMS
AT 28S 45W ALONG 30S 37W...34S 29W...38S 19W...EXITING AT 36S 10W.

AT 500 HPA...A PROGRESSIVE SHORT WAVE TROUGH ON THE NORTHERN
STREAM IS MOVING INTO SOUTHERN/CENTRAL REGIONS OF CHILE WHILE
PRESSING AGAINST A RIDGE TO THE EAST. THE RIDGE EXTENDS SOUTH
ACROSS ARGENTINA TO THE BELLINGSHAUSEN SEA. BROAD TROUGH TO THE
EAST...MEANWHILE...DOMINATES THE FLOW BETWEEN 60W-20W AND TO THE
SOUTH OF 25S.

THE SURFACE ANALYSIS SHOWS A 1013 HPA HIGH AT 65S 60W. TO THE
NORTH...A FRONT EXTENDS FROM A 990 HPA OCCLUDED LOW AT 51S 50W...A
990 HPA TRIPLE POINT LOW AT 50S 47W...48S 52W...50S 58W...52S
64W...53S 64W...64S 68W. A 1017 HPA HIGH CENTERS AT 59S 80W.
RAINFALL WAS BEING REPORTED IN PARTS OF WESTERN PATAGONIA AND IN
PUERTO MONTT WITH THIS SYSTEM. THIS EXTENDS A RIDGE TO THE
NORTHEAST INTO ANOTHER 1017 HPA HIGH AT 46S 66W...AND TO A 1021
HPA HIGH AT 34S 58W...AND INTO EASTERN SAO PAULO/PARANA IN BRASIL.
A 1004 HPA LOW CENTERS AT 44S 76W AND EXTENDS A FRONT ACROSS THE
ANDES INTO A 1014 HPA TRIPLE POINT LOW AT 42S 70W...38S 70W...35S
72W...A 1014 HPA LOW AT 34S 78W...29S 81W...26S 87W...24S 91W. A
1017 HPA HIGH CENTERS AT 31S 94W...AND ANOTHER AT 21S 90W. TO THE
EAST...A FRONT EXTENDS ALONG A 998 HPA LOW AT 37S 27W...34S
28W...31S 30W...30S 33W...A 1010 HPA LOW AT 29S 36W...26S
40W...24S 46W...23S 51W...A 1014 HPA LOW AT 23S 57W...21S
59W...19S 62W. A 1017 HPA HIGH CENTERS AT 17S 33W.

BALBINO...INMET (BRASIL)
DIAZ...INUMET (URUGUAY)
DAVISON/GALVEZ...WPC (USA)