579
FXSA20 KWBC 091404
PMDSA
SOUTH AMERICA SYNOPTIC DISCUSSION - INTERNATIONAL DESKS
NWS HYDROMETEOROLOGICAL PREDICTION CENTER CAMP SPRINGS MD
1004 AM EDT THU OCT 09 2008
GFS DATA AT FTPPRD.NCEP.NOAA.GOV/PUB/DATA/NCCF/COM/GFS/PROD/
SYNOPSIS (VALID FROM 00Z OCT 09). UPPER LEVEL PATTERN OVER
NORTHERN SOUTH AMERICA REMAINS NEARLY UNCHANGED...AS AN UPPER
LEVEL RIDGE DOMINATES CONTINENTAL AREA NORTH OF 20S...AND
CENTERING ON A CLOSED HIGH AT 08S 56W. THIS IS VENTING DEEP
TROPICAL CONVECTION OVER BRASIL TO THE NORTH OF 10S AND WEST OF
50W. THE RIDGE IS STEERING THE DEEP CONVECTION INTO SOUTHERN
VENEZUELA-AMAZONIA IN SOUTHERN COLOMBIA AND NORTHERN PERU. SOUTH
OF THIS RIDGE...A SHORT WAVE TROUGH EXTENDS TO THE NORTHWEST FROM
RIO GRANDE DO SUL BRASIL TO PARAGUAY. AT THIS TIME...THIS FEATURE
ONLY FAVORS HIGH CLOUDS ACROSS SOUTHERN BRASIL WITH LITTLE TO NO
CONVECTION.
THE 250 HPA JET ANALYSIS SHOWS THE SOUTHERN POLAR WITH ENTRANCE
AT 37S 120W...THEN ALONG 43S 102W...EXITING AT 57S 86W. IT HAS
A FINGER WITH ENTRANCE AT 56S 46W...CROSSING 53S 34W...EXITING AT
46S 29W. THE SOUTHERN POLAR HAS ANOTHER BRANCH WITH AXIS ALONG
69S 39W...55S 27W...EXITING AT 52S 05W. THE NORTHERN POLAR LIES
ALONG 32S 120W...A 169KT MAXIMUM AT 35S 108W...EXITING AT 33S
87W. IT REFORMS AT 32S 48W...ALONG 30S 37W...A 131KT MAXIMUM AT
30S 34W...39S 21W...AND A 174KT MAXIMUM AT 43S 12W. THE
SUBTROPICAL JET LIES ALONG 27S 120W...30S 97W...25S 86W...EXITING
NEAR LA SERENA CHILE. IT REFORMS NEAR SAO PAULO BRASIL...CROSSING
25S 35W...EXITING AT 28S 25W. IT REFORMS AGAIN AT 25S 19W...THEN
ALONG 17S 17W...24S 14W...AND 35S 06W.
AT 500 HPA...A LONG WAVE TROUGH AMPLIFIED ALONG 60S 98W...50S
100W...40S 110W...TO 37S 120W. EAST OF THIS AXIS...A SHORT WAVE
TROUGH ALONG 80W AND SOUTH OF 37S IS MOVING TOWARDS SOUTHERN
CHILE...WHILE ANOTHER IS MOVING ACROSS THE ANTARCTIC PENINSULA.
THESE ARE PUSHING AGAINST AND UNDER A RIDGE THAT EXTENDS BETWEEN
70W-50W. FARTHER EAST...OVER THE ATLANTIC...AN ELONGATED TROUGH
EXTENDS ALONG 50S 05W...40S 30W...30S 40W...TO 28S 45W.
AT LOW LEVELS...THE SURFACE ANALYSIS SHOWS A 1025 HPA HIGH NEAR
29S 86W...ANCHORING A RIDGE ON THE NORTHERN STREAM FLOW. ON THE
SOUTHERN STREAM...A BROAD TROUGH DOMINATES THE FLOW...WITH A
POLAR FRONT THAT EXTENDS ALONG A 974 HPA LOW AT 61S 98W...A 978
HPA LOW AT 61S 92W...56S 85W...A 1002 HPA LOW AT 49S 93W...44S
94W...TO A 1014 HPA LOW AT 41S 100W. ANOTHER FRONT LIES ALONG A
1010 HPA LOW AT 50S 80W...46S 77W...A 1014 HPA LOW AT 43S 79W...
36S 79W...AND 31S 91W. FARTHER EAST...AN ELONGATED FRONT LIES
ALONG A 998 HPA LOW AT 60S 48W...54S 49W...A 1010 HPA LOW AT 52S
56W...48S 57W...A 1014 HPA LOW CENTRAL PATAGONIA...TO MENDOZA IN
CENTRAL ARGENTINA. A BROAD RIDGE DOMINATES THE NORTHERN STREAM
FLOW...WITH A 1035 HPA HIGH AT 36S 48W. EAST OF THIS AXIS...A
WANING POLAR FRONT LIES ALONG A 1022 HPA LOW AT 33S 31W...26S
37W...SANTA CATARINA...TO SOUTHEAST PARAGUAY. THIS IS MERGING
WITH AN OLD FRONT THAT EXTENDS ALONG A 1018 HPA LOW AT 31S
27W...25S 31W...RIO DE JANEIRO...MATO GROSSO DO SUL TO NORTHERN
BOLIVIA.
URRA...DMC (CHILE)
MOREYRA...SENAMHI PERU
DAVISON...HPC (USA)
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