Prognostic Meteorological Discussion
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742
FXSA20 KWBC 071433
PMDSA

SOUTH AMERICA SYNOPTIC DISCUSSION - INTERNATIONAL DESKS
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
933 AM EST WED DEC 07 2016

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

SYNOPSIS (VALID FROM DECEMBER 07 AT 0000 UTC): AT 200 HPA...THE
UPPER LEVEL ANALYSIS SHOWS THE BOLIVIAN HIGH CENTERING OVER
SOUTHERN PERU...WHILE ANCHORING A SHORT WAVE RIDGE ACROSS
NORTHWEST SOUTH AMERICA. A TROUGH TO THE EAST EXTENDS FROM 10S 40W
TO EASTERN FRENCH GUIANA. UNDER INFLUENCE OF THE RIDGE TO THE WEST
SCATTERED DEEP CONVECTION WAS BUILDING OVER TOCANTINS-GOIAS...MATO
GROSSO-ACRE/AMAZONAS IN BRASIL...THE PERUVIAN JUNGLE AND PORTIONS
OF BOLIVIA. THE TROUGH...MEANWHILE...FAVORS AN UPPER CONVERGENT
PATTERN OVER NORTHEAST BRASIL WHERE IT IS INHIBITING ORGANIZED
DEEP CONVECTION.

AT 250 HPA...THE SOUTHERN POLAR HAS ITS ENTRANCE AT 59S
117W...THEN ALONG 64S 109W...A 131KT MAXIMUM AT 65S 100W...62S
80W...EXITING AT 56S 70W. IT REFORMS AT 56S 51W...THEN ALONG 56S
32W...44S 18W...AND 44S 01W. THE NORTHERN POLAR HAS ITS ENTRANCE
AT 60S 96W...THEN ALONG 56S 82W...EXITING AT 50S 76W. IT REFORMS
AT 40S 68W...ALONG 39S 57W...EXITING AT 39S 40W. THE SUBTROPICAL
JET HAS A FINGER THAT EXTENDS BETWEEN 47S 90W AND 35S 87W. IT
REFORMS AT 31S 81W...ALONG 34S 59W...EXITING AT 32S 40W. ANOTHER
BRANCH OF THE SUBTROPICAL JET HAS ITS ENTRANCE AT 22S 89W...THEN
ALONG 29S 72W...29S 60W...29S 49W...EXITING AT 25S 40W.

AT 500 HPA...A TROUGH EXTENDS BETWEEN 120W-100W TO 30S. A RIDGE TO
THE EAST...MEANWHILE...LIES FROM 25S 100W...ACROSS 45S 90W...TO
THE BELLINGSHAUSEN SEA. THE RIDGE IS STEERING A SHORT WAVE TROUGH
TO THE EAST NORTHWARD ALONG THE SOUTHERN COAST TOWARDS CENTRAL
PORTIONS OF CHILE. IT ALSO FAVORS THE NORTHWARD AMPLIFICATION OF A
SHORT WAVE TROUGH ACROSS THE DRAKE PASSAGE TO PATAGONIA IN
ARGENTINA. ANOTHER PERTURBATION...MEANWHILE...EXTENDS FROM A
CLOSED LOW AT 45S 50W TO RIO DE LA PLATA BASIN/URUGUAY...WHILE A
SHORT WAVE TROUGH TO THE NORTH EXTENDS FROM 35S 30W TO RIO DE
JANEIRO.

AT LOW LEVELS...THE SURFACE ANALYSIS SHOWS A RIDGE OVER THE FAR
EASTERN PACIFIC...EXTENDING OFF THE COAST OF CHILE TO THE
BELLINGSHAUSEN SEA...WHILE ANCHORING ON A 1025 HPA HIGH AT 36S 90W
AND A 1021 HPA HIGH AT 50S 82W. EAST OF THIS RIDGE...A FRONT
EXTENDS FROM A 986 HPA LOW AT 65S 47W...ALONG 63S 40W...A 986 HPA
TRIPLE POINT LOW AT 60S 39W...56S 41W...54S 48W...A 998 HPA LOW AT
52S 55W...50S 61W...48S 69W...47S 75W...A 1018 HPA LOW AT 45S
78W...40S 81W...AND 39S 86W. THIS FAVORS LIGHT TO MODERATE
RAINFALL ACROSS PATAGONIA IN ARGENTINA. FARTHER NORTH...A DEEP 986
HPA LOW AT 45S 49W EXTENDS A FRONT ALONG 47S 50W...A 990 HPA LOW
AT 47S 47W...45S 43W...A 994 HPA LOW AT 42S 42W...39S 42W...A 1002
HPA LOW AT 37S 43W...34S 45W... NORTHERN URUGUAY TO CENTRAL
ARGENTINA. ANOTHER FRONT TO THE NORTH EXTENDS FROM AN OCCLUDED
1002 HPA LOW AT 34S 27W...36S 23W...A 1006 HPA LOW AT 34S
19W...31S 20W...31S 23W...31S 26W...A 1006 HPA LOW AT 28S
27W...23S 29W...19S 36W...TO ESPIRITO SANTO IN EASTERN BRASIL.
SCATTERED DEEP CONVECTION WAS BUILDING OVER MINAS GERAIS AND BAHIA
TO THE NORTH AND WEST.

ALVA...SENAMHI (PERU)
DURAN...SMN (ARGENTINA)
TEPES...DMC (CHILE)
DAVISON...WPC (USA)
$$





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