Prognostic Meteorological Discussion
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FXSA20 KWBC 191401
PMDSA

SOUTH AMERICA SYNOPTIC DISCUSSION - INTERNATIONAL DESKS
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
900 AM EST FRI DEC 19 2014

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

SYNOPSIS (VALID FROM DECEMBER 19 AT 00UTC): THE ANALYSIS AT 200
HPA SHOWS A BROAD CELL OF THE SUBTROPICAL RIDGE OVER THE CONTINENT
TO THE NORTH OF 30S. A CLOSED HIGH OVER MATO GROSSO IN BRASIL
ANCHORS THIS AXIS. THE RIDGE ALOFT IS VENTING DEEP CONVECTION
ACROSS SOUTH AMERICA TO THE NORTH OF 20S. MOST ACTIVE IS
CLUSTERING ACROSS RONDONIA-AMAZONAS IN BRASIL-SOUTHERN/CENTRAL
PERU. A TROUGH TO THE EAST EXTENDS BETWEEN 40W-25W TO 03N. THIS IS
ENHANCING DIURNAL CONVECTION ACROSS NORTHEAST BRASIL.

AT 250 HPA...THE JET ANALYSIS SHOWS THE SOUTHERN POLAR WITH AXIS
ALONG 55S 120W...54S 98W...49S 82W...49S 75W...49S 67W...50S
51W...EXITING AT 51S 34W. THE NORTHERN POLAR LIES ALONG 49S
120W...A 157KT MAXIMUM AT 50S 98W...45S 82W...A 158KT MAXIMUM AT
45S 73W...45S 66W...EXITING AT 43S 53W. IT HAS A FINGER TO THE
NORTH WITH ENTRANCE AT 34S 51W...THEN ALONG 36S 40W...EXITING AT
42S 31W. THE SUBTROPICAL JET HAS ITS ENTRANCE AT 24S 77W...ALONG
28S 71W...A 131KT MAXIMUM AT 30S 49W...EXITING AT 29S 40W.

AT MID LEVELS...A HIGH NEAR 37S 107W IS BUILDING A RIDGE SOUTH
ALONG 110W TO THE POLAR ICECAP. THIS...IN-TURN...SUSTAINS THE
RAPID AMPLIFICATION OF A TROUGH ACROSS THE BELLINGSHAUSEN
SEA/DRAKE PASSAGE TO THE SOUTHERN CONE. THE AMPLIFYING TROUGH
BOUNDS BETWEEN 100W-50W TO 40S...WITH SHORT WAVE ENERGY FOCUSING
ACROSS THE CONTINENT TO THE SOUTH OF 40S. SHORT WAVE PERTURBATIONS
POPULATE THE NORTHERN STREAM FLOW...WITH ONE EXTENDING ALONG 30S
80W TO 23S 92W...WHILE ANOTHER LIES FROM 40S 40W TO URUGUAY/RIO
GRANDE DO SUL.

AT LOW LEVELS...A BROAD RIDGE OVER THE EASTERN SOUTH PACIFIC
CENTERS ON TWO 1029 HPA HIGHS...WITH ONE AT 35S 109W AND THE OTHER
AT 33S 99W. A BROAD POLAR TROUGH TO THE EAST EXTENDS ACROSS THE
DRAKE PASSAGE TO THE SOUTHERN CONE...WITH A POLAR FRONT EXTENDING
FROM AN OCCLUDED 964 HPA LOW AT 54S 56W...ALONG A 996 HPA LOW AT
54S 52W...47S 47W...45S 53W...A 986 HPA LOW AT 46S 59W...44S
61W...A 986 HPA LOW AT 46S 67W... NORTHERN PATAGONIA...A 1002 HPA
LOW AT 44S 75W...42S 86W...TO 42S 96W. THIS SUSTAINS SCATTERED
CONVECTION ACROSS SOUTHERN PORTIONS OF CHILE. FARTHER EAST AND
NORTH...ANOTHER FRONT LIES ALONG A 998 HPA LOW AT 42S 30W...39S
32W...A 1002 HPA LOW AT 38S 38W...31S 38W...TO SOUTHERN SAO PAULO.
A RIDGE TO THE SOUTH CENTERS ON A 1009 HPA HIGH AT 32S 53W.

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





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