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000
FXSA20 KWBC 211232
PMDSA

SOUTH AMERICA SYNOPTIC DISCUSSION - INTERNATIONAL DESKS
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
831 AM EDT TUE MAY 21 2013

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

SYNOPSIS (VALID FROM 00 UTC MAY 21): NORTH OVER THE CONTINENT...AT
200 HPA...THE UPPER LEVEL ANALYSIS SHOWS A RIDGE EXTENDING WEST
ACROSS THE TROPICAL ATLANTIC TO NORTHEAST BRASIL. SHORT WAVE
PERTURBATIONS TO THE WEST OF THIS AXIS EXPAND ACROSS AMAZONAS AND
PARA IN BRASIL. SATELLITE IMAGERY SHOWS WIDELY ISOLATED CONVECTION
OVER BRASIL TO THE NORTH OF 10S...WITH MOST ACTIVE CONVECTION
CLUSTERING ALONG THE NEAR EQUATORIAL TROUGH OVER THE GUIANAS.

THE JET ANALYSIS SHOWS THE SOUTHERN POLAR WITH AXIS ALONG 54S
120W...A 130KT MAXIMUM AT 52S 98W...EXITING AT 51S 80W. IT REFORMS
AT 53S 74W...ALONG 63S 61W...65S 46W...EXITING AT 59S 28W. THE
NORTHERN POLAR HAS ITS ENTRANCE AT 46S 119W...ALONG 45S 100W...AND
EXITING AT 43S 84W. THE SUBTROPICAL JET LIES ALONG 39S 120W...39S
103W...37S 89W...EXITING AT 32S 82W. IT REFORMS AT 29S
77W...ACROSS RIO DE LA PLATA...32S 43W...27S 31W...28S
16W...EXITING AT 29S 05W. THE JET HAS ANOTHER BRANCH TO THE NORTH
WITH AXIS ALONG 17S 117W...14S 107W...17S 94W...A 130KT MAXIMUM AT
23S 79W...A 141KT MAXIMUM AT 27S 68W...25S 49W...22S 33W...20S
16W...AND 22S 01W.

AT 500 HPA...THE MID LEVEL ANALYSIS SHOWS BROAD TROUGH ON THE
SOUTHERN STREAM EXTENDING BETWEEN 120W-65W AND TO THE SOUTH OF
40S...WHILE CENTERING ON A CLOSED LOW NEAR 67S 89W. THE TROUGH IS
FOCUSING TIS SHORT WAVE ENERGY ACROSS SOUTHERN CHILE TO PATAGONIA
IN ARGENTINA. NORTH OF THIS AXIS...A SHORT WAVE TROUGH EXTENDS
ALONG 30S 80W...23S 90W...TO 16S 100W. THIS IS SHEARING SHORT WAVE
VORTICES ACROSS NORTHERN CHILE TO NORTHERN ARGENTINA-PARAGUAY.
FARTHER EAST...OVER THE ATLANTIC...A RIDGE LIES SOUTH ALONG 50W TO
THE WEDDELL SEA. A CLOSED LOW ON THE NORTHERN STREAM NEAR 40S 27W
ANCHORS A SHORT WAVE TROUGH BETWEEN 40W-15W AND TO THE SOUTH OF
20S.

THE SURFACE ANALYSIS SHOWS BROAD TROUGH ON THE SOUTHERN STREAM
THAT CENTERS ON A DEEP/OCCLUDED 946 HPA LOW AT 67S 83W. POLAR
FRONTS CONTINUE TO REVOLVE AROUND THIS TROUGH...WITH ONE THAT
EXTENDS ALONG A 974 HPA LOW AT 68S 55W...62S 59W...A 982 HPA LOW
AT 59S 70W... TIERRA DEL FUEGO/SOUTHERN PATAGONIA...A 1006 HPA LOW
AT 44S 78W... 39S 77W...35S 85W...AND 36S 95W. THIS IS PHASING
WITH A FRONT TO THE EAST AND NORTH THAT EXTENDS ALONG A 992 HPA
LOW AT 61S 54W...57S 57W...A 990 HPA LOW AT 56S 64W...52S 61W...A
1006 HPA LOW AT 47S 66W...42S 63W...TO CENTRAL CHILE. A RIDGE ON
THE NORTHERN STREAM OVER THE EASTERN PACIFIC CENTERS ON A 1027 HPA
HIGH AT 32S 98W... WHILE ONE OVER THE WESTERN ATLANTIC CENTERS ON
A 1027 HPA HIGH AT 47S 43W. EAST OF THE LATTER...AN OCCLUDED 994
HPA LOW AT 38S 27W ANCHORS A BROAD TROUGH...WITH A POLAR FRONT
THAT LIES ALONG A 1002 HPA LOW AT 42S 29W...37S 20W...30S
24W...28S 36W...TO RIO GRANDE DO SUL. AN OLD BOUNDARY TO THE NORTH
LIES ALONG 19S 30W...22S 39W...A 1014 HPA LOW AT 27S 45W...SAO
PAULO-MATO GROSSO DO SUL TO CENTRAL BOLIVIA.

MAQUEDA...DINAC (PARAGUAY)
SILVA DE SOUZA...INMET (BRASIL)
DAVISON...WPC (USA)
GALVEZ...WPC (USA)

$$