797
FXSA20 KWBC 121332
PMDSA
SOUTH AMERICA SYNOPTIC DISCUSSION - INTERNATIONAL DESKS
NWS HYDROMETEOROLOGICAL PREDICTION CENTER CAMP SPRINGS MD
931 AM EDT FRI SEP 12 2008
GFS DATA AT FTPPRD.NCEP.NOAA.GOV/PUB/DATA/NCCF/COM/GFS/PROD/
SYNOPSIS (VALID FROM 00Z SEP 12). THE UPPER LEVEL PATTERN SHOWS A
NARROW RIDGE OVER NORTHWEST SOUTH AMERICA...CENTERING ON A 200
HPA HIGH OVER NORTHERN PERU. A SECONDARY RIDGE EXTENDS WEST
ACROSS THE TROPICAL ATLANTIC TO THE NORTHERN COAST OF BRASIL. A
SHORT WAVE TROUGH ALONG 48W SEPARATES THESE RIDGES. SATELLITE
IMAGERY SHOWS SCATTERED DEEP CONVECTION BUILDING IN THE LATE
AFTERNOON HOURS OVER BRASIL NORTH OF 05S AND WEST OF 50W.
AT 250 HPA...THE SOUTHERN POLAR LIES ALONG 49S 120W...EXITING AT
46S 108W. IT REFORMS AT 43S 103W...A 148KT MAXIMUM AT 47S
91W...54S 76W...66S 49W...EXITING AT 58S 40W. THE NORTHERN POLAR
EXTENDS BETWEEN 31S 109W AND 36S 93W. IT REFORMS AT 34S
76W...ALONG 30S 66W...40S 39W...A 167KT MAXIMUM AT 36S 78W...28S
15W...AND 36S 00W. THE SUBTROPICAL JET LIES ALONG 27S 120W...26S
108W...31S 85W...EXITING AT 22S 67W. IT REFORMS AT 25S
58W...ALONG 32S 35W...22S 18W...AND 26S 02W.
AT 500 HPA...A BROAD TROUGH ON THE SOUTHERN STREAM FLOW EXTENDS
ACROSS THE SOUTHEAST PACIFIC...AS IT BOUNDS BETWEEN 130W-70W AND
SOUTH OF 40S. THIS TROUGH IS IN PHASE WITH NORTHERN STREAM
PERTURBATIONS...WITH ONE ALONG 115W AND THE OTHER ALONG 103W. THE
SOUTHERN AND NORTHERN STREAM PERTURBATIONS ARE PUSHING AGAINST A
SKEWED RIDGE THAT EXTENDS ALONG 25S 85W...35S 85W...40S 80W...50S
70W...SOUTHERN PATAGONIA...60S 50W...TO JUST EAST OF THE
ANTARCTIC PENINSULA. ON THE NORTHERN STREAM...OVER THE
ATLANTIC...A LOW NEAR 46S 62W EXTENDS A TROUGH OVER THE SOUTHERN
CONE. THIS TROUGH IS FOCUSING ITS SHORT WAVE ENERGY ACROSS
CENTRAL/NORTHERN CHILE-NORTHERN PROVINCES OF ARGENTINA/SOUTHERN
BRASIL AND URUGUAY. THESE WAVES CONTINUE TO TRIGGER ORGANIZED
DEEP CONVECTION ON MID SECTIONS OF SOUTH AMERICA. FARTHER
NORTH...A LOW AMPLITUDE RIDGE EXTENDS OVER SOUTHEAST TO CENTRAL
BRASIL...WHERE IT SUSTAINS A TRADE WIND INVERSION.
AT LOW LEVELS...AN ELONGATED POLAR FRONT LIES ALONG A 994 HPA LOW
AT 68S 56W...64S 55W...62S 64W...A 998 HPA LOW AT 59S 78W...52S
79W...46S 88W...TO 41S 101W. ON THE NORTHERN STREAM...AN OCCLUDED
998 HPA LOW NEAR 36S 101W EXTENDS A FRONT ALONG 35S 104W...A 1010
HPA TRIPLE POINT LOW AT 39S 98W...31S 100W...AND 22S 111W. THIS
FRONT IS SLIDING UNDER A BLOCKING RIDGE OVER THE SOUTHERN
CONE...WHICH ANCHORS ON TWO 1033 HPA HIGHS...WITH ONE NEAR 39S
80W AND 45S 74W. FARTHER EAST...OVER THE ATLANTIC...AN OCCLUDED
1018 HPA LOW NEAR 45S 60W EXTENDS A FRONT ALONG A 1022 HPA TRIPLE
POINT LOW AT 44S 53W...37S 55W...RIO DE LA PLATA TO 35S 65W. A
1029 HPA POLAR HIGH CENTERS NEAR 38S 67W. ANOTHER FRONT EXTENDS
FROM AN OCCLUDING 1010 HPA LOW AT 36S 51W...ALONG A 1014 HPA LOW
AT 33S 46W...28S 46W...SANTA CATARINA BRASIL...A 1012 HPA LOW
NEAR CIUDAD DEL ESTE/FOZ DO IGUAZU...MATO GROSSO DO SUL TO
SOUTHERN BOLIVIA. SCATTERED DEEP CONVECTION WAS BUILDING ALONG
THIS BOUNDARY.
GUZMAN...SENAMHI (BOLIVIA)
URRA...DMC (CHILE)
DAVISON...HPC (USA)
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