342
FXSA20 KWBC 011343
PMDSA
SOUTH AMERICA SYNOPTIC DISCUSSION - INTERNATIONAL DESKS
NWS HYDROMETEOROLOGICAL PREDICTION CENTER CAMP SPRINGS MD
942 AM EDT WED OCT 01 2008
GFS DATA AT FTPPRD.NCEP.NOAA.GOV/PUB/DATA/NCCF/COM/GFS/PROD/
SYNOPSIS (VALID FROM 00Z OCT 01)...AT 200 HPA...A STRONG RIDGE
CENTERED JUST OFF THE CENTRAL PERUVIAN COAST ENCOMPASSES MUCH OF
SOUTH AMERICA NORTH OF 20S WEST OF 55W. ANOTHER RIDGE AXIS IN
THE SUBTROPICAL ATLANTIC EXTENDS WESTWARD INTO NORTHEAST BRASIL.
BETWEEN THESE TWO AXES LIES A WEAK UPPER TROUGH RUNNING ALONG THE
EASTERN BORDER OF TOCANTINS AND GOIAS. VERY DEEP MOISTURE
COMBINED WITH BROAD UPPER DIFFLUENCE IS SUPPORTING A LARGE AREA
OF ORGANIZED CONVECTION OVER SOUTHERN VENEZUELA EASTERN
COLOMBIA EXTREME WESTERN AMAZONIA AND NORTHERN/CENTRAL PERU.
FARTHER EAST ACROSS THE REMAINDER OF THE TROPICS CONVECTION IS
GENERALLY VERY ISOLATED. SCATTERED CONVECTION CAN ALSO BE FOUND
OVER THE HIGHER TERRAIN IN SOUTHERN PERU AND CENTRAL BOLIVIA.
AT 250 HPA THE SOUTHERN POLAR JET ENTERS AT 64S 118W AND EXTENDS
THROUGH 59S 111W BEFORE CROSSING A 130 KT JET MAXIMUM AT 55S 107W
AND EXITING AT 49S 102W. A SHORT STRETCH OF THIS JET REDEVELOPS
AT 45S 101W AND RUNS EASTWARD ACROSS 45S 94W BEFORE EXITING AT
47S 89W. IT REDEVELOPS AGAIN AT 51S 85W PASSES THROUGH A 130 KT
JET MAXIMUM AT 55S 81W THEN CONTINUES THROUGH 60S 70W 65S 50W 65S
31W EXITING AT 60S 16W. THE NORTHERN POLAR JET INITIATES AT 35S
87W THEN RUNS ACROSS 34S 80W 32S 71W BEFORE EXITING AT 34S 64W.
A BRANCH OF THE SUBTROPICAL JET BEGINS AT 18S 110W AND RUNS
ACROSS 22S 100W 25S 88W PASSING THROUGH A 155 KT JET MAXIMUM AT
27S 76W THEN CONTINUES TO 26S 69W BEFORE EXITING AT 26S 63W.
AT 500 HPA A STRONG POLAR VORTEX CENTERED AT 68S 94W EXTENDS AN
AMPLIFIED TROUGH BETWEEN 85-100W NORTHWARD TO APPROXIMATELY 40S.
ONE SHORT WAVE EMBEDDED IN THIS TROUGH EXTENDS FROM 55S 87W
THROUGH 50S 91W 46S 94W 43S 98W. A SECOND VORTICITY MAXIMUM AT
55S 103W IS DIVING INTO THE WESTERN END OF THIS TROUGH. A
NORTHERN STREAM TROUGH RUNS FROM 43S 78W THROUGH 36S 75W 30S
72W 25S 71W. AS THIS SYSTEM APPROACHES THE COAST IT IS BRINGING
MOSTLY LIGHT RAIN SHOWERS INTO SOUTH-CENTRAL CHILE AND ALSO
SPAWNING A FEW SHOWERS OVER THE HIGHER TERRAIN OF WEST-CENTRAL
ARGENTINA. DOWNSTREAM A RIDGE AXIS EXTENDS FROM CENTRAL PARAGUAY
THROUGH URUGUAY AND BUENOS AIRES PROVINCE THEN CONTINUES
GENERALLY SOUTHWARD ALONG 55W TO 55S. IN THE WESTERN
ATLANTIC TWO TROUGHS ARE EMBEDDED IN THE NORTHERN STREAM FLOW.
ONE RUNS FROM 50S 43W ACROSS 45S 47W 40S 49W 37S 51W. A SECOND
WAVE STRETCHES FROM 33S 44W THROUGH 28S 45W 24S 46W. ELSEWHERE A
BROAD SUBTROPICAL RIDGE EXTENDS FROM SOUTHERN PERU
EAST-SOUTHEASTWARD ACROSS THE CONTINENT INTO NORTHEAST BRASIL.
AT THE SURFACE A 986 HPA SURFACE WAVE LOCATED AT 61S 74W HAS AN
ASSOCIATED WARM FRONT EXTENDING EAST THROUGH 61S 70W 61S 65W 61S
61W. A WEAK COLD FRONT RUNS FROM THE LOW ACROSS 59S 74W AND 57S
75W BEFORE TRANSITIONING TO A WARM FRONT AT 56S 77W AND
CONTINUING ACROSS 55S 81W REACHING A TRIPLE POINT AT 52S 85W. A
990 HPA LOW ASSOCIATED WITH A STRONG SOUTHERN STREAM SHORT WAVE
IS CENTERED NEAR 51S 89W WITH AN OCCLUDED FRONT RUNNING FROM 49S
90W 50S 92W 53S 90W TO THE AFOREMENTIONED TRIPLE POINT AT 52S
85W. FROM THIS POINT A COLD FRONT EXTENDS THROUGH 49S 87W 45S
90W 42S 95W 41S 102W. FARTHER NORTH A 1014 HPA CYCLONE AT 39S
78W HAS AN OCCLUDED FRONT EXTENDING FROM 40S 77W THROUGH 37S
76W 36S 78W 38S 81W 41S 82W 45S 79W BECOMING A COLD FRONT AT 44S
77W AND CONTINUING NORTHWARD ACROSS 41S 74W 35S 73W 31S 76W. A
1021 HPA HIGH AT 44S 54W ANCHORS A RIDGE EXTENDING THROUGH BUENOS
AIRES PROVINCE URUGUAY NORTHERN ARGENTINA AND SOUTHERN BRASIL. A
WAVY STATIONARY BOUNDARY EXTENDS FROM 22S 35W THROUGH 21S
43W...19S 49W 23S 54W 25S 59W 22S 63W 16S 65W 13S 69W. THERE IS
SOME SCATTERED CONVECTION ASSOCIATED WITH THE WESTERN END OF THIS
FRONT MAINLY FROM CENTRAL BOLIVIA NORTHWEST INTO THE SOUTHERN
JUNGLES OF PERU. ELSEWHERE A SQUALL LINE IS ANALYZED IN WESTERN
ARGENTINA FROM 31S 68W ACROSS 35S 67W TO 40S 68W. ELSEWHERE A
WEAK STATIONARY FRONT EXTENDS FROM 60S 36W THROUGH 57S 48W 55S
61W 52S 68W ENDING IN SOUTHERN PATAGONIA NEAR 47S 70W.
URRA.....DMC (CHILE)
MOREYRA...SENAMHI PERU
KLEIN..HPC (USA)
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