406
FXSA20 KWBC 081318
PMDSA
SOUTH AMERICA SYNOPTIC DISCUSSION - INTERNATIONAL DESKS
NWS HYDROMETEOROLOGICAL PREDICTION CENTER CAMP SPRINGS MD
918 AM EDT FRI AUG 08 2008
GFS DATA AT FTPPRD.NCEP.NOAA.GOV/PUB/DATA/NCCF/COM/GFS/PROD/
SYNOPSIS (VALID FROM 00Z AUG 08). THE SATELLITE IMAGERY CONTINUES
TO SHOW CLUSTERS OF DEEP CONVECTION ACROSS WESTERN BRASIL...
AFFECTING PORTIONS OF PARA-AMAZONAS-RONDONIA. THE SUBTROPICAL
RIDGE ALOFT IS PROVIDING VENTILATION TO THIS CONVECTION...AS THE
RIDGE EXTENDS ACROSS CONTINENTAL AREA NORTH OF 20S/23S. THE RIDGE
CENTERS ON A HIGH NEAR 10S 50W. CONVECTIVE ACTIVITY...HOWEVER...
IS INTENSIFYING ACROSS SOUTHERN PERU-NORTHERN BOLIVIA AS AN UPPER
LEVEL SHORT WAVE TROUGH NEARS THE NORTHERN COAST OF CHILE/
SOUTHERN PERU.
AT 250 HPA...THE SOUTHERN POLAR LIES ALONG 63S 120W...57S
108W...EXITING AT 47S 111W. IT REFORMS AT 37S 101W...ALONG 44S
91W...PUERTO MONTT...38S 53W...A 146KT MAXIMUM AT 46S 29W...AND
49S 12W. THE NORTHERN POLAR LIES ALONG 31S 120W...29S 110W...A
162KT MAXIMUM AT 30S 103W...EXITING AT 33S 93W. IT REFORMS AT 37S
79W...ALONG 33S 48W...40S 24W...AND 39S 08W. THE SUBTROPICAL JET
LIES ALONG 16S 120W...26S 103W...25S 89W...EXITING AT 15S 79W. IT
REFORMS AT 18S 69W...ALONG 26S 56W...29S 38W...EXITING AT 25S
33W.
AT 500 HPA...A RIDGE IS BUILDING SOUTH ALONG 125W/130W. EAST OF
THIS RIDGE...ON THE NORTHERN STREAM FLOW...A TROUGH EXTENDS
BETWEEN 125W-90W AND SOUTH OF 20S...CENTERING ON A LOW NEAR 42S
102W. THE TROUGH IS INDUCING A SHORT WAVE RIDGE ALONG 85W.
FARTHER EAST...OVER THE ANTARCTIC PENINSULA AND WESTERN
ATLANTIC...ANALYSIS SHOWS A BROAD TROUGH EXTENDING BETWEEN 75W-
15W AND SOUTH OF 28S. NUMEROUS SHORT WAVE PERTURBATIONS ARE
REVOLVING AROUND THIS AXIS...WITH A STRONG VORTEX ACROSS THE
DRAKE PASSAGE/THE MALVINAS. THERE IS AN ELONGATED CYCLONIC TONGUE
THAT EXTENDS ALONG 50S 20W...43S 40W...40S 50W...RIO DE LA PLATA
TO MENDOZA IN ARGENTINA. OTHER VORTICES ARE STREAMING ACROSS
BOLIVIA-PARAGUAY-SOUTHERN BRASIL. THESE ARE INTERACTING WITH A
QUASISTATIONARY FRONT OVER BRASIL...TRIGGERING ORGANIZED DEEP
CONVECTION.
AT LOW LEVELS...THE SURFACE ANALYSIS SHOWS A RIDGE ON THE
SOUTHERN STREAM WITH AXIS ALONG A 1033 HPA HIGH AT 45S 120W...51S
100W...TO SOUTHERN CHILE. SOUTH OF THIS RIDGE...A STREAM OF SHORT
WAVE PERTURBATIONS ARE RACING TOWARDS THE SOUTHERN CONE/DRAKE
PASSAGE...WITH PROGRESSIVE POLAR FRONTS LIMITING TO AREA SOUTH OF
50S. ON THE NORTHERN STREAM...A 1018 HPA LOW AT 40S 81W EXTENDS A
FRONT ALONG 37S 80W...40S 85W...A 1014 HPA LOW AT 40S 93W...37S
92W...33S 95W...A 1014 HPA LOW AT 32S 101W...AND 27S 103W. THIS
SYSTEM IS PUSHING AGAINST A RIDGE OVER THE EASTERN PACIFIC/
SOUTHERN CONE...CENTERING ON THREE 1027 HPA HIGHS...WITH ONE NEAR
33S 81W...TEMUCO CHILE...AND CORDOBA IN ARGENTINA. FARTHER
EAST...OVER THE ATLANTIC...A BROAD TROUGH DOMINATES THE SOUTHERN
AND NORTHERN STREAMS. EMBEDDED IN THIS FLOW...A 978 HPA LOW AT
53S 20W EXTENDS A FRONT ALONG 55S 19W...A 986 HPA TRIPLE POINT
LOW AT 52S 15W...45S 22W...43S 31W...A 1006 HPA LOW AT 36S
40W...32S 42W...TO 30S 47W. ANOTHER FRONT LIES ALONG A 1012 HPA
LOW AT 39S 30W...36S 30W...A 1012 HPA LOW AT 33S 36W...29S
37W...SAO PAULO TO PARAGUAY. SCATTERED DEEP CONVECTION WAS
BUILDING OVER SOUTHERN BRASIL.
GUZMAN...SENAMHI (BOLIVIA)
URRA...DMC (CHILE)
DAVISON...HPC (USA)
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