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000
FXSA20 KWBC 181433
PMDSA

SOUTH AMERICA SYNOPTIC DISCUSSION - INTERNATIONAL DESKS
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
932 AM EST WED JAN 18 2017

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

SYNOPSIS (VALID FROM JANUARY 18 AT 0000 UTC): THE 200 HPA ANALYSIS
SHOWS A BROAD CELL OF THE SUBTROPICAL RIDGE ENVELOPING CONTINENTAL
AREA TO THE NORTH OF 40S AND WEST OF 55W...WITH AXIS ANCHORING ON
A CLOSED HIGH NEAR 24S 70W. A SHORT WAVE TROUGH TO THE EAST
EXTENDS NORTH ACROSS THE SOUTHERN TO SOUTHEAST STATES OF
BRASIL...WHILE A TUTT TO THE NORTHEAST EXTENDS ALONG 20S 30W...A
LOW AT 10S 40W TO THE GUIANAS. THE RIDGE ALOFT IS VENTING DEEP
CONVECTION ACROSS THE ALTIPLANO OF BOLIVIA/CHILE AND THE SIERRA OF
PERU...WHILE THE SHORT WAVE TROUGH FAVORS SCATTERED DEEP
CONVECTION ON THE SOUTHEAST STATES OF BRASIL. MOST ACTIVE
CONVECTION IS CLUSTERING TO THE NORTH ALONG THE NEAR EQUATORIAL
TROUGH OVER NORTHERN PARA-RORAIMA IN BRASIL.

THE 250 HPA JET ANALYSIS SHOWS THE SOUTHERN POLAR WITH ENTRANCE AT
56S 80W...THEN ALONG 51S 70W...EXITING AT 48S 58W. IT REFORMS AT
49S 52W...THEN ALONG 54S 39W...53S 14W...AND 47S 01W. THE NORTHERN
POLAR HAS ITS ENTRANCE AT 48S 96W...THEN ALONG 48S 81W...43S
70W...41S 65W...EXITING AT 42S 57W. A FINGER OF THE NORTHERN POLAR
TO THE NORTH HAS ITS ENTRANCE AT 35S 97W...CROSSING 40S
94W...EXITING AT 53S 89W. THE SUBTROPICAL JET HAS ITS ENTRANCE AT
31S 88W...THEN ALONG 36S 81W...36S 70W...35S 61W...EXITING AT 32S
55W. THE SUBEQUATORIAL JET...AT 180 HPA...LIES ALONG 09S
114W...14S 107W... 14S 99W...EXITING AT 10S 94W.

AT 500 HPA...IN A TIGHT BELT OF MID LATITUDE WESTERLIES...
PROGRESSIVE SHORT WAVE TROUGHS ARE STREAMING ACROSS THE SOUTHEAST
PACIFIC-SOUTHERN CONE OF SOUTH AMERICA. ONE EXTENDS ALONG 90W TO
45S...WHILE ANOTHER IS PULLING ACROSS 60W TO THE BUENOS AIRES
PROVINCE IN ARGENTINA. A SHORT WAVE TROUGH ON THE NORTHERN
STREAM...MEANWHILE...EXTENDS FROM 40S 96W TO 26S 100W. THE LATTER
IS PRESSING AGAINST A RIDGE TO THE EAST THAT EXTENDS BETWEEN
95W-60W AND NORTH OF 35S...WHILE ANCHORING ON A CLOSED HIGH AT 27S
79W.

AT LOW LEVELS...RIDGE ON THE NORTHERN STREAM OFF THE COAST OF
CHILE ANCHORS ON TWO 1021 HPA HIGHS...WITH ONE AT 35S 83W AND THE
OTHER AT 39S 80W. PROGRESSIVE FRONT TO THE SOUTH EXTENDS FROM AN
OCCLUDED 986 HPA LOW AT 56S 92W...A 1002 HPA LOW AT 51S 84W...47S
84W...TO 44S 94W. FARTHER EAST OVER THE SOUTH ATLANTIC...A DEEP
OCCLUDED 970 HPA LOW AT 61S 43W ANCHORS A TROUGH ON THE SOUTHERN
STREAM FLOW...WITH A POLAR FRONT TO THE NORTH EXTENDING ALONG A
990 HPA LOW AT 54S 20W...50S 21W...47S 30W...46S 41W...A 994 HPA
LOW AT 46S 48W...41S 49W...35S 54W...RIO DE LA PLATA... SOUTHERN
CORDOBA-MENDOZA IN ARGENTINA...SANTIAGO....AND 36S 78W. A RIDGE TO
THE SOUTH ANCHORS ON A 1007 HPA HIGH AT 40S 61W. ANOTHER FRONT TO
THE EAST AND NORTH EXTENDS ALONG A 998 HPA LOW AT 42S 42W...38S
44W...36S 48W...A 1002 HPA LOW AT 33S 49W...30S 46W...SAO PAULO TO
MATO GROSSO DO SUL. THIS SUSTAINS ORGANIZED DEEP CONVECTION. BROAD
RIDGE TO THE EAST ANCHORS ON A 1029 HPA HIGH AT 38S 18W.

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





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