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FXSA20 KWBC 281312
PMDSA

SOUTH AMERICA SYNOPTIC DISCUSSION - INTERNATIONAL DESKS
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
911 AM EDT THU MAY 28 2015

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

SYNOPSIS (VALID FROM MAY 28 AT 00UTC): ANALYSIS AT 200 HPA SHOWS
BROAD CELL OF THE SUBTROPICAL RIDGE ACROSS THE EASTERN TROPICAL
PACIFIC...WITH AXIS ANCHORING ON A CLOSED HIGH OFF THE COAST OF
PERU NEAR 05S 85W. A TROUGH TO THE EAST EXTENDS ACROSS CENTRAL
BRASIL...WITH AXIS NORTH BETWEEN 65W-50W TO THE SOUTHERN GUIANAS.
THIS TROUGH IS ENHANCING CONVECTIVE DEVELOPMENT ACROSS PARA AND
THE AMAZON RIVER DELTA REGION IN BRASIL.

THE 250 JET ANALYSIS SHOWS THE SOUTHERN POLAR JET FORMING AT 56S
79W EXITING AT 55S 62W. IT REFORMS AT 56S 46W ALONG A 129KT MAXIMA
AT 46S 36W...41S 21W...43S 08W. ANOTHER BRANCH FORMS AT 42S 84W
ALONG 49S 78W...51S 71W...EXITING AT 48S 59W. IT REFORMS AT 47S
50W EXITING AT 42S 32W. THE NORTHERN POLAR FORMS AT 32S 102W ALONG
32S 95W...35S 85W...EXITING AT 41S 75W. IT REFORMS AT 36S 54W
ALONG 40S 47W...40S 36W...38S 20W...A 212KT MAXIMA AT 40S 07W. THE
SUBTROPICAL JET EXTENDS ALONG 26S 106W...A 167KT MAXIMA AT 31S
91W...32S 78W...A 139KT MAXIMA AT 29S 71W...A 128KT MAXIMA AT 24S
67W...21S 60W...28S 52W...35S 45W...34S 25W...37S 05W.

AT 500 HPA...A TROUGH EXTENDS BETWEEN 100W-80W AND TO THE SOUTH OF
25S...WHILE ANCHORING ON A CLOSED LOW NEAR 48S 93W. THE TROUGH IS
PRESSING AGAINST A RIDGE TO THE EAST THAT EXTENDS FROM 20S
80W...ACROSS 35S 70W...PATAGONIA TO THE DRAKE PASSAGE. DOWNSTREAM
FROM THIS AXIS...A SHORT WAVE TROUGH EXTENDS FROM URUGUAY/RIO
GRANDE DO SUL IN BRASIL TO SOUTHERN BOLIVIA. THE TROUGH IS
INTERACTING WITH A SURFACE FRONT IN SUPPORT OF CYCLOGENESIS OVER
SOUTHERN BRASIL.

THE SURFACE ANALYSIS SHOWS A 972 HPA LOW AT 48S 92W EXTENDING A
FRONT ALONG 47S 87W...46S 94W...52S 95W...A 982 HPA LOW AT 48S
84W...43S 79W...A 994 HPA LOW AT 42S 81W...37S 81W...31S 86W...27S
93W. RAINFALL WAS OCCURRING IN SOUTHERN CHILE IN ASSOCIATION WITH
THIS SYSTEM. A 998 HPA OCCLUDED LOW AT 59S 65W EXTENDS A FRONT
INTO A 1002 HPA LOW AT 56S 55W...52S 56W...A 1010 HPA LOW AT 50S
58W...A WEAK SURFACE COLD FRONT INTO 46S 57W...42S 62W...A 1014
HPA LOW AT 44S 67W...AND ANOTHER WEAK COLD FRONT INTO 38S 69W.  A
1021 HPA HIGH CENTERS AT 26S 82W. TO THE SOUTHEAST...A 1025 HPA
HIGH CENTERS AT 40S 47W AND RIDGES INTO ANOTHER 1025 HPA HIGH AT
34S 35W. A 1010 HPA LOW AT 29S 50W EXTENDS A FRONT ALONG A 1010
HPA HIGH AT 28S 46W...24S 47W...20S 52W...A 1012 HPA LOW AT 19S
57W...15S 59W...15S 67W IN NORTHWESTERN BOLIVIA. SCATTERED
RAINFALL WAS OCCURRING WITH THIS SYSTEM IN SOUTHERN BRASIL AND
URUGUAY...AND THUNDERSTORMS OVER BOLIVIA.

CHARPENTIER...DMC (CHILE)
SCHNEIDER...INMET (BRASIL)
UNSIHUAY...UNALM (PERU)
GALVEZ...WPC (USA)
$$





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