THE WEATHER PREDICTION CENTER

COLLEGE PARK, MD


SOUTH AMERICAN SYNOPSIS




SOUTH AMERICA SYNOPTIC DISCUSSION - INTERNATIONAL DESKS
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
900 AM EDT TUE JUL 29 2014

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

SYNOPSIS (VALID FROM 29 JULY 00UTC): THE 200 HPA ANALYSIS SHOWS
RIDGE OVER THE EASTERN PACIFIC ORIGINATING NEAR THE GALAPAGOS
ISLANDS...WITH AXIS SOUTHEAST ALONG THE COAST OF PERU...ACROSS
NORTHERN CHILE TO RIO DE LA PLATA BASIN IN ARGENTINA. AN ELONGATED
TROUGH LIES TO THE EAST OF THIS RIDGE...WITH AXIS NORTHWEST ACROSS
SOUTHERN BRASIL-MATO GROSSO TO AMAZONAS IN WESTERN BRASIL. THIS
TROUGH IS ENHANCING DIURNAL CONVECTION ACROSS AMAZONAS-PARA IN
BRASIL. OTHER CONVECTION WAS CLUSTERING BETWEEN PERNAMBUCO AND RIO
GRANDE DO NORTE. THIS ASSOCIATES WITH A NORTHERN HEMISPHERE
TROPICAL DISTURBANCE ALONG 40W.

AT 250 HPA...THE SOUTHERN POLAR HAS ITS ENTRANCE AT 48S
107W...THEN ALONG 45S 96W...EXITING AT 40S 86W. IT REFORMS AT 40S
72W...ALONG 42S 64W...51S 52W...50S 41W...EXITING AT 46S 35W. THE
NORTHERN POLAR LIES ALONG A 196KT MAXIMUM AT 35S 120W...37S
111W...41S 100W...A 148KT MAXIMUM AT 40S 95W...36S 89W...35S
79W...A 148KT MAXIMUM AT 36S 70W...EXITING AT 38S 59W. IT REFORMS
AT 42S 48W...ALONG 33S 39W...32S 32W...36S 24W...41S 14W...AND A
164KT MAXIMUM AT 44S 10W. THE SUBTROPICAL JET HAS ITS ENTRANCE AT
21S 90W...CROSSING 22S 80W...EXITING AT 18S 73W. IT REFORMS TO THE
EAST NEAR 27S 43W... ALONG 29S 32W...34S 20W...37S 10W...AND 40S
00W. THE SUBTROPICAL JET HAS ANOTHER BRANCH TO THE NORTH WITH
ENTRANCE AT 14S 51W...ACROSS RIO DE JANEIRO...A 122KT MAXIMUM AT
27S 30W...EXITING AT 29S 21W.

AT 500 HPA...BROAD TROUGH DOMINATES FLOW ACROSS THE SOUTHEAST
PACIFIC...WHILE CENTERING ON A CLOSED LOW AT 58S 100W. SHORT WAVE
PERTURBATIONS ON THE NORTHERN STREAM FLOW REVOLVE AROUND THIS
AXIS...WITH ONE PULLING ACROSS 115W AS ANOTHER MOVES ACROSS 83W. A
SHORT WAVE RIDGE ALONG 100W TO 45S SEPARATES THESE PERTURBATIONS.
A THIRD SHORT WAVE TROUGH EXITED THE COAST OF PATAGONIA...WITH
AXIS NORTH ALONG 64W TO THE BUENOS AIRES PROVINCE. A
NORTH-TO-SOUTH RIDGE ALONG 50W DOMINATES FLOW OVER THE WESTERN
ATLANTIC...WHILE A TROUGH TO THE EAST EXTENDS TO THE NORTHWEST
ALONG 50S 20W...40S 34W...TO 30S 40W.

AT LOW LEVELS...THE SURFACE ANALYSIS SHOWS A BROAD TROUGH ON THE
SOUTHERN STREAM CENTERING ON AN OCCLUDED 970 HPA LOW AT 58S 101W.
POLAR FRONTS REVOLVE AROUND THIS AXIS...WITH ONE THAT EXTENDS FROM
AN OCCLUDED 994 HPA LOW AT 52S 63W...ALONG A 994 HPA LOW AT 52S
61W...47S 58W...44S 61W...A 1010 HPA LOW AT 43S 64W...38S
67W...36S 71W...A 1014 HPA LOW AT 35S 74W...31S 76W...29S 80W...A
1018 HPA LOW AT 29S 83W...AND 25S 91W. A SECONDARY FRONT
FOLLOWS...AS IT EXTENDS FROM A 982 HPA LOW AT 55S 89W...ALONG 50S
87W...A 990 HPA LOW AT 46S 87W...44S 80W...A 1002 HPA LOW AT 40S
78W...36S 77W...TO 33S 83W. A RIDGE ON THE NORTHERN STREAM
DOMINATES THE WESTERN ATLANTIC... ANCHORING ON A 1037 HPA HIGH AT
40S 44W. AN OLD BOUNDARY TO THE EAST AND NORTH LIES ALONG A 1022
HPA LOW AT 33S 22W...30S 24W...28S 26W...VITORIA...MINAS
GERAIS/GOIAS TO MATO GROSSO/NORTHERN BOLIVIA.

FERNANDES...INMET (BRASIL)
JALFIN...SMN (ARGENTINA)
DAVISON...WPC (USA)





Last Updated: 900 AM EDT TUE JUL 29 2014