555
FXSA20 KWBC 181324
PMDSA
SOUTH AMERICA SYNOPTIC DISCUSSION - INTERNATIONAL DESKS
NWS HYDROMETEOROLOGICAL PREDICTION CENTER CAMP SPRINGS MD
924 AM EDT THU SEP 18 2008
GFS DATA AT FTPPRD.NCEP.NOAA.GOV/PUB/DATA/NCCF/COM/GFS/PROD/
SYNOPSIS (VALID FROM 00Z SEP 18). THE 200 HPA ANALYSIS SHOWS A
COMPLEX PATTERN OVER NORTHERN SOUTH AMERICA...WITH A NORTHERN
HEMISPHERE LOW THAT CENTERS NEAR 04N 44W...EXTENDING A SHORT WAVE
TROUGH ACROSS THE AMAZON RIVER DELTA TO 09S 50W. THIS TROUGH IS
PHASING WITH A SHORT WAVE RIDGE OVER PARA/AMAZONAS-RONDONIA IN
WESTERN BRASIL. THE LATTER IS VENTING ISOLATED LATE AFTERNOON
CONVECTION ACROSS WESTERN BRASIL-NORTHERN JUNGLE OF PERU AND
AMAZONIA IN SOUTHERN COLOMBIA.
AT 250 HPA...THE SOUTHERN POLAR HAS ITS ENTRANCE NEAR 40S 116W...
THEN ALONG 50S 96W...EXITING AT 44S 80W. IT REFORMS AT 44S
67W...CROSSING A 126KT MAXIMUM AT 56S 52W...61S 34W...EXITING AT
53S 19W. THE NORTHERN POLAR LIES ALONG A 138KT MAXIMUM AT 30S
120W...40S 94W...EXITING AT 29S 75W. IT HAS A FINGER BETWEEN 37S
67W AND 44S 55W...REFORMING FARTHER EAST NEAR 41S 42W...THEN
ALONG 27S 46W...33S 21W...AND A 146KT MAXIMUM AT 37S 01W. THE
SUBTROPICAL JET LIES ALONG 19S 120W...20S 103W...EXITING AT 16S
85W. IT REFORMS NEAR 17S 59W...CROSSING VITORIA IN EASTERN
BRASIL...A 138KT MAXIMUM AT 26S 26W....EXITING AT 26S 01W.
AT 500 HPA...A TROUGH IS DIGGING TO THE NORTHWEST ALONG 65S
100W...58S 110W...50S 120W...TO 37S 130W. THIS TROUGH IS
INTERACTING WITH A NORTHERN STREAM VORTEX THAT STRETCHES ALONG
50S 108W...40S 115W...30S 120W...TO 27S 125W. A RIDGE ALONG 90W
SEPARATES THESE TROUGHS FROM A BROAD TROUGH OVER THE ANTARCTIC
PENINSULA/DRAKE PASSAGE-SOUTHERN CONE TO THE EASTERN PACIFIC.
ALONG THIS AXIS A NORTHERN STREAM VORTEX IS SEGREGATING OFF THE
CENTRAL COAST OF CHILE. A SKEWED RIDGE EXTENDS FROM CHACO
ARGENTINO...ACROSS RIO DE LA PLATA...50S 40W...60S 35W...TO 70S
35W. FURTHERMORE...ON THE NORTHERN STREAM...A LOW NEAR 36S 32W
EXTENDS A TROUGH TO THE NORTHWEST INTO SOUTHEAST/SOUTHERN BRASIL.
THE SURFACE ANALYSIS SHOWS A RIDGE OVER THE EASTERN PACIFIC
CENTERING ON A 1033 HPA HIGH AT 39S 84W. EAST AND SOUTH OF THIS
RIDGE...A POLAR FRONT EXTENDS FROM AN OCCLUDED 958 HPA LOW AT 63S
53W...THEN ALONG A 962 HPA LOW AT 62S 50W...54S 52W...A 1014 HPA
LOW AT 47S 59W...LA PAMPA IN ARGENTINA...CENTRAL CHILE...TO A
1022 HPA LOW/WAVE OFF THE COAST NEAR 33S 73W. A RIDGE OVER THE
ATLANTIC CENTERS ON TWO 1033 HPA HIGHS...WITH ONE NEAR 46S 15W
AND THE OTHER NEAR 46S 36W. THERE IS ALSO A 1029 HPA HIGH AT 26S
44W. A BROAD TROUGH TO THE NORTH CENTERS ON AN OCCLUDED 1010 HPA
LOW AT 35S 32W. THERE IS ALSO A POLAR FRONT THAT EXTENDS ALONG A
1014 HPA LOW AT 30S 19W...24S 27W...20S 34W...ESPIRITO SANTO/
MINAS GERAIS-MATO GROSSO DO SUL TO NORTHERN BOLIVIA. THIS FAVORS
SCATTERED RAINFALL ACROSS RIO DE JANEIRO/NORTHERN SAO PAULO TO
SOUTHERN MINAS GERAIS.
GUZMAN...SENAMHI (BOLIVIA)
URRA...DMC (CHILE)
DAVISON...HPC (USA)
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