020
FXSA20 KWBC 241359
PMDSA
SOUTH AMERICA SYNOPTIC DISCUSSION - INTERNATIONAL DESKS
NWS HYDROMETEOROLOGICAL PREDICTION CENTER CAMP SPRINGS MD
958 AM EDT WED SEP 24 2008
GFS DATA AT FTPPRD.NCEP.NOAA.GOV/PUB/DATA/NCCF/COM/GFS/PROD/
SYNOPSIS (VALID FROM 00Z SEP 24). IN A TRANSITIONAL WEATHER
PATTERN...THE 200 HPA ANALYSIS SHOWS A CELL OF THE SUBTROPICAL
RIDGE ESTABLISHING OVER THE CONTINENT ON A CLOSED HIGH NEAR 08S
65W. THE HIGH ANCHORS A RIDGE THAT EXTENDS WEST OF 55W AND BOUNDS
BETWEEN 20S-05N. ANOTHER CELL LIES TO THE EAST...CENTERING ON A
CLOSED HIGH NEAR 04S 35W. A TROUGH ALONG 50W SEPARATES THESE
RIDGES...WHILE ALSO SUSTAINING AN AREA OFF DIVERGENCE ALOFT
ACROSS BAHIA-ESPIRITO SANTO IN NORTHEAST BRASIL. THE SATELLITE
IMAGERY SHOWS MOST ACTIVE CONVECTION BUILDING NORTH OF 04S AND
WEST OF THE AMAZON RIVER DELTA/ILHA DE MARAJO.
THE 250 HPA JET ANALYSIS SHOWS THE SOUTHERN POLAR WITH A FINGER
THAT EXTENDS BETWEEN 56S 88W AND 70S 52W. IT REFORMS FARTHER
NORTH...WITH ENTRANCE AT 41S 30W...AND ALONG A 135KT MAXIMUM AT
38S 04W. THE NORTHERN POLAR LIES ALONG A 132KT MAXIMUM AT 43S
120W...32S 110W...A 126KT MAXIMUM AT 35S 99W...EXITING AT 42S
81W. IT REFORMS NEAR 25S 44W...THEN ALONG 34S 28W...35S 09W...AND
33S 00W. THE SUBTROPICAL JET HAS ITS ENTRANCE AT 19S 120W...THEN
ALONG 22S 99W...22S 81W...25S 64W...EXITING AT 18S 51W. IT
REFORMS AT 18S 43W...ALONG A 131KT MAXIMUM AT 27S 30W...A 128KT
MAXIMUM AT 31S 17W...AND 27S 00W.
AT 500 HPA...A SKEWED RIDGE EXTENDS TO THE SOUTHWEST ALONG 30S
130W...50S 110W...TO 60S 100W. EAST OF THIS RIDGE...A LONG WAVE
TROUGH LIES ALONG A LOW NEAR 62S 90W...50S 100W...40S 100W...TO
30S 110W. A SECONDARY LOW IS STARTING TO FORM ALONG THIS AXIS
NEAR 43S 100W. EAST OF THIS SYSTEM...OVER THE SOUTHERN CONE...A
SHORT WAVE TROUGH EXTENDS FROM SOUTHERN PATAGONIA/TIERRA DEL
FUEGO TO TEMUCO CHILE. ON THE NORTHERN STREAM...MEANWHILE...A
SHORT WAVE TROUGH IS APPROACHING NORTHERN CHILE. THESE ARE
PUSHING EAST AGAINST A BLOCKING RIDGE THAT EXTENDS FROM
PARAGUAY...ACROSS URUGUAY...TO 60S 50W. DOWNSTREAM FROM THIS
AXIS...OVER THE ATLANTIC...A NORTHERN STREAM TROUGH EXTENDS ALONG
37S 35W...30S 40W...TO SAO PAULO IN BRASIL.
AT LOW LEVELS...A TROUGH OVER THE EASTERN PACIFIC SUPPORTS A
POLAR FRONT THAT EXTENDS ALONG A 990 HPA OCCLUDED LOW AT 46S
95W...A 994 HPA LOW AT 43S 92W...33S 97W...ISLA DE PASCUA...AND
25S 112W. ANOTHER FRONT EXTENDS ALONG A 978 HPA LOW AT 61S
88W...A 982 HPA LOW AT 62S 82W...57S 80W...A 994 HPA LOW AT 53S
84W...TO 48S 80W. IT IS INTERACTING WITH A WEAKER FRONT TO THE
NORTH THAT EXTENDS FROM A 1008 HPA LOW AT 47S 80W...ALONG 43S
76W...TO 40S 78W. FARTHER EAST...OVER THE WESTERN ATLANTIC...A
BROAD TROUGH DOMINATES THE SOUTHERN CONE...CENTERING ON AN
OCCLUDED 998 HPA LOW AT 53S 64W...A 1002 HPA LOW AT 53S 59W...47S
57W...A 1012 HPA LOW AT 45S 61W...41S 62W...TO MENDOZA IN
ARGENTINA. RIDGES EXTEND ON THE NORTHERN STREAM...WITH ONE OVER
THE EASTERN PACIFIC CENTERING ON TWO 1021 HPA HIGHS...WITH ONE
NEAR 30S 84W AND THE OTHER AT 39S 74W. ANOTHER RIDGE OVER THE
ATLANTIC ALSO CENTERS ON TWO 1027 HPA HIGHS...WITH ONE NEAR 38S
50W AND 48S 42W. THERE IS ALSO A POLAR FRONT TO THE EAST AND
NORTH...EXTENDING FROM A 1006 HPA LOW AT 33S 34W...THEN ALONG 32S
38W...A 1014 HPA LOW AT 35S 26W...28S 29W...A 1012 HPA LOW AT 26S
33W...22S 36W...VITORIA BRASIL...SOUTHERN MINAS GERAIS TO
NORTHERN BOLIVIA. A PREFRONTAL TROUGH EXTENDS NORTHWEST ACROSS
BAHIA...WHERE IT FAVORS ISOLATED TO SCATTERED DEEP CONVECTION.
GUZMAN...SENAMHI (BOLIVIA)
URRA...DMC (CHILE)
DAVISON...HPC (USA)
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