Prognostic Meteorological Discussion
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000
FXSA20 KWBC 281351
PMDSA

SOUTH AMERICA SYNOPTIC DISCUSSION - INTERNATIONAL DESKS
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
851 AM EST TUE FEB 28 2017

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

SYNOPSIS (VALID FROM FEBRUARY 28 AT 0000 UTC): AT 200 HPA...A HIGH
OVER SOUTHERN BOLIVIA ANCHORS A RIDGE OVER THE CONTINENT TO THE
WEST OF 60W AND NORTH OF 30S. THE RIDGE ALOFT IS VENTING
CONVECTION ACROSS THE ALTIPLANO OF BOLIVIA-SOUTHERN PERU AND THE
NORTHWEST PROVINCES IN ARGENTINA. A TROUGH TO THE
EAST...MEANWHILE...EXTENDS FROM A CLOSED LOW AT 27S 45W TO MATO
GROSSO IN BRASIL. THE TROUGH ALOFT IS ENHANCING CONVECTIVE
DEVELOPMENT ACROSS MINAS GERAIS-TOCANTINS/GOIAS...WHILE ALSO
FAVORING A SURGE IN CONVECTION ACROSS PARA AND THE NORTHEAST
STATES OF BRASIL.

AT 250 HPA...THE SOUTHERN POLAR LIES ALONG 63S 116W...56S
110W...51S 104W...EXITING AT 47S 95W. A FINGER OF THE SOUTHERN
POLAR LIES BETWEEN 50S 84W AND 60S 81W. IT REFORMS AT 64S
74W...THEN ALONG A 128KT MAXIMUM AT 56S 50W...A 129KT MAXIMUM AT
51S 34W...A 142KT MAXIMUM AT 49S 24W...46S 14W...AND 45S 06W. THE
NORTHERN POLAR LIES ALONG A 127KT MAXIMUM AT 40S 120W...A 129KT
MAXIMUM AT 42S 111W...A 138KT MAXIMUM AT 41S 100W...A 140KT
MAXIMUM AT 41S 90W...44S 83W...A 138KT MAXIMUM AT 49S
80W...EXITING AT 54S 74W. IT REFORMS AT 53S 66W...THEN ALONG 51S
44W...48S 34W...45S 20W...AND 43S 10W. THE SUBTROPICAL JET LIES
ALONG 37S 120W...38S 110W...38S 103W...37S 91W...EXITING AT 37S
84W. A FINGER OF THE SUBTROPICAL JET TO THE NORTH LIES BETWEEN 26S
72W AND 31S 60W.

AT 500 HPA...DEEP LOW NEAR 60S 100W ANCHORS A TROUGH OVER THE
SOUTHEAST PACIFIC. THE TROUGH EXTENDS BETWEEN 100W-80W AND TO THE
SOUTH OF 35S. THE DEEP TROUGH SUSTAINS AN INDUCED RIDGE TO THE
EAST THAT EXTENDS FROM PATAGONIA IN ARGENTINA TO THE
BELLINGSHAUSEN SEA. A BROAD/LOW AMPLITUDE TROUGH TO THE EAST
EXTENDS BETWEEN 70W-00W AND TO THE SOUTH OF 40S.

AT LOW LEVELS...THE SURFACE ANALYSIS SHOWS A BROAD TROUGH OVER THE
SOUTHEAST PACIFIC THAT CENTERS ON AN OCCLUDED 958 HPA LOW AT 57S
90W. THIS EXTENDS A FRONT ALONG 60S 84W...A 974 HPA LOW AT 57S
80W...52S 75W...49S 78W...A 988 HPA LOW AT 47S 81W...43S 81W...42S
83W...A 1002 HPA LOW AT 40S 88W...35S 91W...33S 97W...AND A 1014
HPA LOW AT 33S 102W. A PREFRONTAL TROUGH EXTENDS ACROSS PATAGONIA
TO LA PAMPA IN ARGENTINA...WHILE A RIDGE TO THE EAST CENTERS ON A
1009 HPA HIGH AT 46S 56W. EAST OF THIS AXIS...AN ELONGATED POLAR
FRONT LIES ALONG A 1002 HPA LOW AT 49S 40W...44S 44W...43S 49W...A
1006 HPA LOW AT 41S 56W...BUENOS AIRES TO MENDOZA IN ARGENTINA.
THIS FAVORS SCATTERED CONVECTION ACROSS CENTRAL PROVINCES IN
ARGENTINA.

ABDEMUR...FAA (ARGENTINA)
TEPES...DMC (CHILE)
GALVEZ/DAVISON...WPC (USA)
$$




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