Prognostic Meteorological Discussion
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FXSA20 KWBC 161341
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SOUTH AMERICA SYNOPTIC DISCUSSION - INTERNATIONAL DESKS
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
941 AM EDT WED AUG 16 2017

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

SYNOPSIS (VALID FROM AUG 16 AT 0000 UTC): AT 200 HPA...A RIDGE
EXTENDS WEST FROM A CLOSED HIGH AT 07S 30W...ACROSS NORTHERN
BRASIL-CENTRAL PERU TO THE EASTERN TROPICAL PACIFIC. THIS COMBINES
WITH MID LEVEL RIDGE TO FAVOR A STRONG TRADE WINDS CAP ACROSS
CENTRAL-NORTHEAST STATES OF BRASIL. IN THIS PATTERN ORGANIZED
CONVECTION LIMITS TO EQUATORIAL SOUTH AMERICA...WITH MOST ACTIVE
TO THE NORTH OF THE EQUATOR. OTHER CONVECTION TO THE SOUTH
CLUSTERED ALONG AN ELONGATED FRONT OVER SOUTHEAST BRASIL...MATO
GROSSO DO SUL-BOLIVIA.

THE 250 HPA JET ANALYSIS SHOWS THE SOUTHERN POLAR FORMING AT 37S
117W ALONG 44S 108W...49S 98W...A 138KT MAXIMA AT 49S 90W...47S
76W...EXITING AT 43S 68W. IT REFORMS AT 37S 55W ALONG 41S
45W...45S 34W...A 150KT MAXIMA AT 52S 20W. THE NORTHERN POLAR JET
EXTENDS ALONG 36S 109W...40S 100W...42S 88W...40S 78W...EXITING AT
32S 73W. IT REFORMS AT 30S 65W ALONG 31S 54W...33S 44W...38S
32W...45S 24W. THE SUBTROPICAL JET FORMS AT 19S 82W ALONG 21S
67W...25S 54W...28S 45W...EXITING AT 31S 30W. THE SUBEQUATORIAL
JET FORMS AT 18S 55W ALONG 21S 45W...20S 35W...EXITING AT 15S 26W.

AT 500 HPA...A RIDGE ON THE NORTHERN STREAM DOMINATES THE FLOW
OVER THE EASTERN PACIFIC BETWEEN 105W-80W AND TO THE NORTH OF 50S.
A PROGRESSIVE SHORT WAVE TROUGH ON THE SOUTHERN STREAM IS FLOWING
UNDER THIS AXIS...EXTENDING TO THE NORTHWEST FROM A CLOSED LOW AT
67S 85W TO 50S 107W. FARTHER EAST...A LONG WAVE TROUGH EXTENDS
FROM A CLOSED LOW AT 62S 51W...ALONG 50S 55W...THE BUENOS AIRES
PROVINCE TO CENTRAL ARGENTINA. A SECONDARY SHORT WAVE TROUGH OFF
THE NORTH COAST OF CHILE FOLLOWS.

THE SURFACE ANALYSIS SHOWS A FRONT EXTENDING ALONG 51S 62W...A 982
HPA LOW AT 60S 71W...56S 81W...A 998 HPA LOW AT 54S 89W...49S
100W. A 1006 HPA LOW AT 51S 68W EXTENDS A FRONT ALONG 44S
70W...45S 77W...A 1010 HPA LOW AT 47S 83W...44S 86W...A 1014 HPA
LOW AT 45S 94W. A 1031 HPA HIGH AT 33S 87W EXTENDS A RIDGE ALONG A
1029 HPA HIGH AT 37S 79W AND INTO A 1029 HPA HIGH AT 39S 73W. OVER
THE ATLANTIC...A 998 HPA LOW AT 49S 49W EXTENDS A FRONT ALONG 45S
51W...A 1006 HPA LOW AT 44S 53W...40S 55W...A 1014 HPA LOW AT 39S
57W...36S 66W. ANOTHER FRONT EXTENDS ALONG A 1006 HPA LOW AT 46S
45W...41S 46W...A 1010 HPA LOW AT 41S 50W...34S 54W...31S 69W. A
FRONT EXTENDS ALONG A 1022 HPA LOW AT 43S 27W...38S 33W...31S
41W...25S 41W...22S 42W...A 1010 HPA LOW AT 20S 47W...19S 53W...A
1012 HPA LOW AT 19S 56W...17S 58W...16S 62W...12S 70W. A 1021 HPA
HIGH CENTERS AT 22S 27W. A FRONT EXTENDS ALONG 13S 24W...11S
29W...10S 37W. THIS SYSTEM ALSO EXTENDS A SHEAR LINE ALONG 13S
23W...08S 29W...02S 34W.

GONZALEZ...DMC (CHILE)
VANNUCCI...SMN (ARGENTINA)
DAVISON/GALVEZ...WPC (USA)
$$





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