SOUTH AMERICA SYNOPTIC DISCUSSION - INTERNATIONAL DESKS
NWS HYDROMETEOROLOGICAL PREDICTION CENTER CAMP SPRINGS MD
915 AM EDT FRI MAY 16 2008
 
GFS DATA AT FTPPRD.NCEP.NOAA.GOV/PUB/DATA/NCCF/COM/GFS/PROD/
 
SYNOPSIS (VALID FROM 00Z MAY 16). AT UPPER LEVELS...A 200 HPA
RIDGE EXTENDS WEST ACROSS NORTHERN SOUTH AMERICA...WITH MEAN AXIS
ALONG 06S/05W TRAVERSING BRASIL TO NORTHERN PERU. OVERALL...THE
RIDGE ENVELOPS AREA NORTH OF 20S AND EAST OF 60W/65W. ALTHOUGH
THE RIDGE PATTERN INTENSIFIED OVER NORTHERN SOUTH AMERICA...THE
PATTERN OF DEEP TROPICAL CONVECTION CONFINES TO AREA NORTH OF
05S. AN ELONGATED TROUGH WRAPS AROUND THE SOUTHERN AND WESTERN
PERIPHERY OF THIS RIDGE...AS IT EXTENDS ACROSS SOUTHERN BRASIL-
CHACO ARGENTINO...ALTIPLANO OF BOLIVIA INTO THE SIERRA OF PERU.
THE SATELLITE IMAGERY SHOWS WIDELY ISOLATED CONVECTION ON THE
CENTRAL SIERRA OF PERU...WITH A CLUSTER OF DEEP CONVECTION
CONFINING TO EL PANTANAL/MATO GROSSO DO SUL AND BORDER REGION
WITH PARAGUAY.

THE 250 HPA JET ANALYSIS SHOWS THE SOUTHERN POLAR WITH AXIS ALONG
73S 77W...A 120KT MAXIMUM AT 62S 87W...57S 83W...PUNTA ARENAS
CHILE...47S 52W...48S 31W...AND 49S 01W. THE NORTHERN POLAR LIES
ALONG A 159KT MAXIMUM AT 33S 132W...31S 119W...27S 105W...26S
94W...A 136KT MAXIMUM AT 37S 88W...45S 82W...A 170KT MAXIMUM AT
45S 71W...A 181KT MAXIMUM AT 42S 58W...40S 47W...A 170KT MAXIMUM
AT 45S 31W...AND 156KT MAXIMUM AT 48S 13W. THE SUBTROPICAL JET
HAS A FINGER WITH ENTRANCE AT 17S 104W...CROSSING A 126KT MAXIMUM
AT 21S 94W...EXITING AT 29S 81W. IT REFORMS AT 15S 64W...CROSSING
A 135KT MAXIMUM AT 24S 42W...A 155KT MAXIMUM AT 26S 26W...AND 24S
06W.

AT 500 HPA...A NARROW RIDGE EXTENDS SOUTH ALONG 105W/110W TO 80S.
THIS RIDGE...IN-TURN...IS INDUCING THE RAPID NORTHWARD MIGRATION
OF AN OCCLUDING CLOSED LOW THAT CENTERS NEAR 61S 77W...WITH A
BROAD TROUGH INTO THE DRAKE PASSAGE. ON THE NORTHERN STREAM...A
LOW NEAR 34S 97W EXTENDS A TROUGH NORTH ALONG 97W/98W TO 15S. THE
LATTER IS INDUCING A RIDGE THAT EXTENDS ALONG THE COAST OF CHILE.
OVER THE ATLANTIC...MEANWHILE...A BROAD TROUGH PATTERN DOMINATES
AREA BOUND BETWEEN 60W-20W AND SOUTH OF 30S. EMBEDDED IN THIS
FLOW...AN ELONGATED TROUGH/CYCLONIC TONGUE EXTENDS ALONG 50S
30W...43S 50W...TO 42S 60W. NORTH OVER THE CONTINENT...A SHORT
WAVE TROUGH EXTENDS FROM RIO GRANDE DO SUL IN SOUTHERN BRASIL TO
SOUTHERN BOLIVIA.

ON THE SURFACE ANALYSIS...A DUAL BARRELED RIDGE EXTENDS OVER THE
ANTARCTIC PENINSULA...WITH A 1017 HPA HIGH NEAR 68S 89W AND A
1011 HPA HIGH AT 63S 55W. AN OCCLUDING TROUGH ENTERED THE DRAKE
PASSAGE...CENTERING ON A 992 HPA LOW AT 60S 70W. A POLAR FRONT
EXTENDS FROM A 994 HPA LOW AT 57S 74W...ALONG 52S 73W...50S
80W...A 1006 HPA LOW AT 53S 87W...47S 89W...AND 46S 97W. THIS
FAVORS MODERATE RAINFALL OVER EXTREME SOUTHERN CHILE/TIERRA DEL
FUEGO. A RIDGE TO THE NORTH CENTERS ON TWO HIGHS...A 1019 HPA
HIGH AT 47S 76W AND A 1021 HPA HIGH AT 41S 65W.  A BROAD TROUGH
ON THE NORTHERN STREAM CENTERS ON A 996 HPA LOW AT 34S 98W. AN
ELONGATED FRONT LIES ALONG A 972 HPA TRIPLE POINT LOW AT 48S
21W...THEN 40S 31W...38S 40W...A 1010 HPA LOW AT 37S 48W...RIO DE
LA PLATA...36S 61W...36S 67W...39S 74W...TO A 1006 HPA LOW AT 38S
83W...34S 81W...32S 85W...A 1006 HPA LOW AT 30S 90W...25S
90W...AND A 1010 HPA LOW AT 22S 94W.  MODERATE RAINFALL WAS
REPORTED OVER SOUTHERN CHILE...WHILE OVER BUENOS AIRES PROVINCE
LIGHT POST FRONTAL RAINFALL AFFECTED THE SOUTHERN PORTIONS OF THE
PROVINCE. OVER THE ATLANTIC...A RIDGE EXTENDS WEST BETWEEN 20S-
30S TO SOUTHERN BRASIL...WITH A 1025 HPA HIGH AT 25S 12W...A 1021
HPA HIGH AT 27S 31W...AND A 1019 HPA HIGH AT 27S 51W. AN
ELONGATED FRONT ENTERS BAHIA BRASIL...THEN SOUTHWEST ACROSS MINAS
GERAIS/BAHIA-MATO GROSSO DO SUL TO BOLIVIA.

CARVAJAL...DAC (ECUADOR)
COLMAN...DMH (PARAGUAY) 
DAVISON...HPC (USA)