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South American Synoptic Discussion
 
(Caution: Version displayed is not the latest version. - Issued 1344Z Dec 05, 2014)
 
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SOUTH AMERICA SYNOPTIC DISCUSSION - INTERNATIONAL DESKS
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
844 AM EST FRI DEC 05 2014

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

SYNOPSIS (VALID FROM DECEMBER 05 AT 00UTC): NORTH OVER THE
CONTINENT...AT 200 HPA...THE SUBTROPICAL HIGH NOW CENTERS OVER
WESTERN BOLIVIA NEAR 13S 67W...ANCHORING A RIDGE ACROSS
PERU-ACRE/AMAZONAS IN BRASIL-BOLIVIA TO ARGENTINA. A SECONDARY
RIDGE EXTENDS WEST ACROSS MATO GROSSO-SOUTHERN MINAS
GERAIS/NORTHERN SAO PAULO IN BRASIL TO THE WESTERN ATLANTIC. THIS
RIDGE UNDERCUTS A TROUGH TO THE NORTH...AS THE LATTER EXTENDS
ALONG 20S 30W...10S 50W...TO RORAIMA IN BRASIL. THE TROUGH IS
ENHANCING COASTAL CONVECTION ACROSS NORTHERN BRASIL...WHILE ALSO
ENHANCING DIURNAL CONVECTION ACROSS MATO GROSSO-TOCANTINS/GOIAS
AND PORTIONS OF BAHIA. THE RIDGE ALOFT...MEANWHILE...VENTS DEEP
CONVECTION TO THE NORTH...WITH CELLS CLUSTERING ACROSS
ACRE-RONDONIA/AMAZONAS IN BRASIL TO CENTRAL/NORTHERN PERU.

AT 250 HPA...THE SOUTHERN POLAR LIES ALONG 47S 140W...56S 126W...A
188KT MAXIMUM AT 55S 109W...52S 96W...48S 90W...EXITING AT 43S
89W. IT REFORMS AT 43S 82W...ALONG A 150KT MAXIMUM AT 48S
74W...51S 59W...EXITING AT 46S 42W. THE NORTHERN POLAR LIES ALONG
34S 144W...A 162KT MAXIMUM AT 44S 136W...51S 126W...A 149KT
MAXIMUM AT 51S 110W...48S 98W...40S 95W...EXITING AT 32S 96W. IT
REFORMS AT 29S 93W...ALONG 36S 82W...A 126KT MAXIMUM AT 44S
73W...47S 66W...A 140KT MAXIMUM AT 47S 59W...39S 42W...39S 32W...A
143KT MAXIMUM AT 44S 18W...AND 48S 04W. THE SUBTROPICAL JET HAS
ITS ENTRANCE AT 20S 112W...ALONG 20S 102W...23S 91W...29S
81W...37S 73W...EXITING AT 40S 60W.

AT 500 HPA...THE MID LEVEL ANALYSIS SHOWS A HIGHLY AMPLIFIED LONG
WAVE PATTERN OVER THE SOUTH AMERICAN DOMAIN...WITH A LONG WAVE
RIDGE EXTENDING BETWEEN CENTRAL SOUTH AMERICA-ANTARCTIC PENINSULA
AND ALONG 60W. THIS RIDGE SEPARATES TWO TROUGHS...ONE OVER THE
EASTERN PACIFIC AND THE OTHER OVER THE ATLANTIC. THE ONE OVER THE
PACIFIC EXTENDS FROM 65S 95W...ALONG 60S 82W...50S 85W...40S
86W...35S 90W...30S 95W...TO 25S 105W. THIS IS FOCUSING SHORT WAVE
ENERGY ACROSS SOUTHERN PORTIONS OF CHILE/TIERRA DEL FUEGO. THE
OTHER TROUGH TO THE EAST BOUNDS BETWEEN 50W-10W AND TO THE SOUTH
OF 30S.

AT LOW LEVELS...THE SURFACE ANALYSIS SHOWS A BROAD RIDGE ON THE
NORTHERN STREAM THAT CENTERS ON A 1025 HPA HIGH AT 32S 117W. EAST
OF THIS AXIS...A POLAR FRONT EXTENDS FROM A 1002 HPA LOW AT 51S
63W...ALONG 47S 68W...46S 75W...A 1006 HPA LOW AT 44S 81W...36S
80W...AND 27S 87W. THIS SUSTAINS LIGHT RAINFALL ACROSS SOUTHERN
CHILE. A RIDGE OVER THE ATLANTIC CENTERS ON A 1021 HPA HIGH AT 42S
49W. A POLAR FRONT TO THE EAST LIES ALONG A 1010 HPA LOW AT 35S
30W...28S 37W...RIO DE JANEIRO...TO 21S 52W. THIS SUSTAINS
SCATTERED DEEP CONVECTION ACROSS NORTHERN SAO PAULO.

ARREAGA...INAMHI (ECUADOR)
DURAN...SENAMHI (PERU)
DAVISON...WPC (USA)