Prognostic Meteorological Discussion
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000
FXSA20 KWBC 041352
PMDSA

SOUTH AMERICA SYNOPTIC DISCUSSION - INTERNATIONAL DESKS
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
951 AM EDT TUE AUG 04 2015

GFS DATA AT FTPPRD.NCEP.NOAA.GOV/PUB/DATA/NCCF/COM/GFS/PROD/

SYNOPSIS (VALID FROM AUG 04 AT 0000 UTC): A NORTHERN HEMISPHERE
LOW CENTERS SOUTH OF THE GUIANAS NEAR 00N 57W...ANCHORING AN UPPER
LEVEL TROUGH OVER EQUATORIAL SOUTH AMERICA. THIS IS ENHANCING
DIURNAL CONVECTION ACROSS RORAIMA-NORTHERN AMAZONAS IN BRASIL TO
SOUTHERN COLOMBIA/NORTHERN JUNGLE OF ECUADOR. OTHERWISE...FAIR
WEATHER CONDITIONS PREVAIL TO THE NORTH.

THE 250 HPA JET ANALYSIS SHOWS THE SOUTHERN POLAR FORMING AT 48S
78W ALONG 39S 47W...A 160KT MAXIMA AT 43S 25W. THE NORTHERN POLAR
JET EXTENDS ALONG A 168KT MAXIMA AT 31S 110W...32S 100W...35S
90W...EXITING AT 35S 86W. IT REFORMS AT 35S 78W ALONG 38S 65W...A
126KT MAXIMA AT 35S 50W...36S 38W...39S 25W. THE SUBTROPICAL JET
FORMS AT 25S 76W ALONG 31S 63W...30S 43W...31S 30W...EXITING AT
28S 21W.

AT 500 HPA...AMPLIFYING TROUGH ON THE SOUTHERN STREAM FLOW EXTENDS
FROM A CLOSED LOW AT 74S 92W...ALONG 60S 105W...TO 50S 114W. NORTH
OF THIS AXIS...TIGHT BELT OF MID LATITUDE WESTERLIES DOMINATES
FLOW BETWEEN 20S-35S. THIS IS ADVECTING DEEP SUBTROPICAL MOISTURE
FROM THE CENTRAL PACIFIC TO THE SOUTHERN CONE OF SOUTH AMERICA. A
LOW AMPLITUDE RIDGE OVER ARGENTINA SEPARATES THIS FROM A LOW
AMPLITUDE TROUGH OVER THE WESTERN ATLANTIC.

THE SURFACE SHOWS A 994 HPA LOW AT 62S 44W EXTENDING A FRONT ALONG
59S 45W...55S 57W...A 1006 HPA LOW AT 56S 65W...52S 68W...A 1006
HPA LOW AT 54S 79W...52S 84W. RAINFALL WAS OCCURRING IN EXTREME
SOUTHWESTERN CHILE. A 978 HPA OCCLUDED LOW AT 41S 95W EXTENDS A
FRONT ALONG 39S 98W...44S 95W INTO A 986 HPA TRIPLE LOW AT 42S
90W...39S 90W...36S 93W...34S 96W...31S 98W. A 1021 HPA HIGH
CENTERS AT 38S 61W. TO THE EAST A 1006 HPA LOW AT 37S 35W EXTENDS
A COLD FRONT ALONG 35S 34W...30S 39W...30S 46W...30S 55W...28S
64W. ISOLATED THUNDERSTORMS WERE OCCURRING ALONG THIS BOUNDARY.

ROMERO...DMC (CHILE)
FARINA...DMH (PARAGUAY)
GALVEZ...WPC (USA)
$$




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