Prognostic Meteorological Discussion
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FXSA20 KWBC 301256
PMDSA

SOUTH AMERICA SYNOPTIC DISCUSSION - INTERNATIONAL DESKS
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
856 AM EDT FRI SEP 30 2016

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

SYNOPSIS (VALID FROM SEPTEMBER 30 AT 0000 UTC): THE 200 HPA
ANALYSIS SHOWS LOW AMPLITUDE RIDGE OVER THE CONTINENT TO THE NORTH
OF 10S. THIS IS VENTING DIURNAL CONVECTION ACROSS NORTHERN BRASIL
IN THE PERUVIAN JUNGLE AND PORTIONS OF ECUADOR. A SHORT WAVE
TROUGH IS MOVING ACROSS THE EASTERN PACIFIC TOWARDS PERU. THIS
TROUGH WAS ENHANCING CONVECTIVE DEVELOPMENT ALONG THE
CENTRAL/SOUTHERN SIERRA.

THE 250 HPA ANALYSIS SHOWS A FINGER OF THE SOUTHERN POLAR WITH
ENTRANCE AT 56S 80W...THEN ALONG 61S 65W...EXITING AT 61S 46W. THE
NORTHERN POLAR HAS A FINGER WITH ENTRANCE AT 35S 82W...THEN ALONG
34S 75W...EXITING AT 36S 69W. IT REFORMS AT 39S 56W...THEN ALONG A
120KT MAXIMUM AT 32S 42W...30S 32W...40S 14W...AND 41S 02W. THE
SUBTROPICAL JET HAS ITS ENTRANCE AT 31S 89W...THEN ALONG30S
70W...31S 58W...25S 36W...EXITING AT 27S 24W. IT HAS A BRANCH TO
THE NORTH WITH AXIS ALONG 15S 120W...A 126KT MAXIMUM AT 21S
101W...25S 93W...A 127KT MAXIMUM AT 27S 85W...25S 73W...25S
55W...EXITING AT 23S 44W. THE SUBTROPICAL JET REFORMS AT 15S
34W...THEN ALONG 20S 23W...26S 10W...AND 29S 06W.

AT 500 HPA...A SKEWED RIDGE OVER THE PACIFIC EXTENDS ALONG 24S
120W...30S 115W...40S 110W...50S 100W...TO 54S 100W. A SHORT WAVE
TROUGH TO THE EAST EXTENDS ACROSS THE BELLINGSHAUSEN SEA...55S
85W...A CLOSED LOW AT 46S 90W...TO 40S 92W. THIS IS INTERACTING
WITH A SHORT WAVE TROUGH TO THE NORTH THAT EXTENDS FROM A CLOSED
LOW AT 43S 79W...ALONG 35S 75W...TO 28S 75W. OVER THE
CONTINENT...A RIDGE EXTENDS SOUTH FROM PARAGUAY...ACROSS THE
BUENOS AIRES PROVINCE TO THE MALVINAS/FALKLAND ISLANDS...WHERE IT
FORKS TO THE EAST-SOUTHEAST ACROSS THE SOUTH GEORGIA ISLANDS. OVER
THE ATLANTIC...BROAD TROUGH DOMINATES THE FLOW BETWEEN 50W-20W AND
TO THE SOUTH OF 20S...WITH AXIS CENTERING ON A CLOSED LOW AT 47S
27W.

AT LOW LEVELS...BROAD RIDGE DOMINATES THE FLOW OVER THE EASTERN
PACIFIC...ANCHORING ON TWO HIGHS...A 1025 HPA AT 30S 100W AND A
1023 HPA AT 43S 98W. AN ELONGATED FRONT TO THE SOUTH EXTENDS FROM
AN OCCLUDED 978 HPA LOW AT 69S 36W...A 986 HPA LOW AT 61S
31W...61S 37W...61S 49W...A 998 HPA LOW AT 65S 55W...62S 57W...61S
63W...A 998 HPA LOW AT 64S 69W...61S 71W...A 1002 HPA LOW AT 60S
75W...56S 78W...A 1014 HPA LOW AT 47S 87W...45S 85W...39S
90W...37S 96W...TO A 1016 HPA LOW AT 35S 109W. ANOTHER FRONT TO
THE NORTH EXTENDS OVER THE SOUTHERN CONE WHILE ORIGINATING ON AN
OCCLUDED 1014 HPA LOW AT 45S 77W...A 1014 HPA LOW AT 45S
68W...NORTHERN PATAGONIA...A 1014 HPA LOW AT 39S 75W...35S
75W...TO 32S 73W. THIS FAVORS LIGHT RAINFALL ACROSS SOUTHERN CHILE
AND LIGHT TO MODERATE CONVECTION ACROSS NORTHERN PATAGONIA TO
CENTRAL ARGENTINA. A BROAD RIDGE OVER THE ATLANTIC ANCHORS ON A
1027 HPA HIGH AT 44S 58W. BROAD TROUGH TO THE EAST CENTERS ON AN
OCCLUDED 994 HPA LOW AT 45S 27W. THIS EXTENDS A FRONT ALONG A 994
HPA LOW AT 45S 22W...A 996 HPA LOW AT 45S 17W...A 1002 HPA LOW AT
37S 21W...34S 24W...A 1006 HPA LOW AT 31S 29W...27S 34W...25S
43W...SAO PAULO-SOUTHEAST PARAGUAY TO CORRIENTES IN ARGENTINA.

ALVA...SENAMHI (PERU)
DAVISON/GALVEZ...WPC (USA)
$$




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