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South American Synoptic Discussion
 
(Caution: Version displayed is not the latest version. - Issued 1342Z May 18, 2018)
 
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SOUTH AMERICA SYNOPTIC DISCUSSION - INTERNATIONAL DESKS
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
942 AM EDT FRI MAY 18 2018

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

SYNOPSIS (VALID FROM MAY 18 AT 0000 UTC): AT 200 HPA...AN EAST TO
WEST RIDGE TRAVERSES THE CONTINENT TO THE NORTH OF 10S WHILE
CENTERING ON A CLOSED HIGH NEAR 07S 47W. THE RIDGE ALOFT IS
VENTING LATE AFTERNOON/EVENING CONVECTION THAT CLUSTERED ACROSS
AMAZONAS-ACRE IN BRASIL AND THE CENTRAL/NORTHERN JUNGLE OF PERU.

AT 250 HPA...THE SOUTHERN POLAR HAS ITS ENTRANCE AT 40S 16W...THEN
ALONG 42S 107W...A 180KT MAXIMUM AT 44S 100W...EXITING AT 50S 90W.
IT REFORMS AT 68S 93W...THEN ALONG 70S 86W...71S 72W...69S
57W...64S 54W...EXITING AT 60S 58W. IT REFORMS AT 52S 58W...THEN
ALONG 48S 53W...45S 45W...44S 38W...43S 33W...43S 25W...45S
20W...AND 51S 03W. THE NORTHERN POLAR HAS ITS ENTRANCE AT 27S
122W...THEN ALONG 30S 117W...37S 110W...A 162KT MAXIMUM AT 40S
104W...41S 98W...42S 90W...EXITING AT 34S 74W. IT REFORMS AT 35S
57W...THEN ALONG A 122KT MAXIMUM AT 38S 45W...36S 27W...38S
20W...A 151KT MAXIMUM AT 41S 13W...AND 47S 00W. THE SUBTROPICAL
JET LIES ALONG 22S 120W...28S 114W...32S 107W...35S 97W...35S
88W...31S 79W...29S 71W...28S 61W...29S 52W...30S 43W...29S
34W...32S 25W...A 135KT MAXIMUM AT 35S 20W...EXITING AT 38S 07W.

AT 500 HPA...A SKEWED RIDGE EXTENDS TO THE SOUTH-SOUTHEAST FROM A
CLOSED HIGH AT 22S 89W...ALONG 50S 80W TO THE DRAKE
PASSAGE/ANTARCTIC PENINSULA. AN ELONGATED TROUGH TO THE WEST
PRESSES AGAINST THIS RIDGE...WITH AXIS EXTENDING TO THE NORTHWEST
FROM A CLOSED LOW AT 51S 104W...ALONG 40S 110W...TO 30S 125W.
DOWNSTREAM FROM THE RIDGE...A SHORT WAVE TROUGH ON THE NORTHERN
STREAM IS LIFTING ACROSS CENTRAL CHILE TO CUYO IN ARGENTINA.
FARTHER EAST...OVER THE SOUTH ATLANTIC...BROAD TROUGH DOMINATES
THE FLOW TO THE EAST OF 60W AND TO THE SOUTH OF 24S.

AT LOW LEVELS...BROAD RIDGE ON THE NORTHERN STREAM LIES OVER THE
FAR EASTERN PACIFIC WHILE CENTERING ON A 1025 HPA HIGH AT 34S 84W.
DOWNSTREAM FROM THIS AXIS...A RIDGE ON THE SOUTHERN STREAM ANCHORS
ON A 1017 HPA HIGH AT 56S 59W. IN A SPLIT FLOW PATTERN...AN
OCCLUDED 1010 HPA LOW AT 41S 62W EXTENDS A FRONT ALONG A 1010 HPA
LOW AT 40S 60W...BUENOS AIRES PROVINCE-MENDOZA TO A 1018 HPA LOW
AT 30S 74W. BROAD TROUGH OVER THE SOUTH ATLANTIC CENTERS ON AN
OCCLUDED 974 HPA LOW AT 48S 31W. THIS EXTENDS A FRONT ALONG A 974
HPA LOW AT 48S 29W...44S 27W...39S 32W...37S 40W...38S 47W...AND
41S 51W. AN OLD FRONT TO THE NORTH LIES ALONG A 998 HPA LOW AT 45S
08W...42S 09W...A 1006 HPA LOW AT 39S 12W...35S 14W...A 1014 HPA
LOW AT 32S 20W...30S 20W...A 1018 HPA LOW AT 28S 24W...25S
27W...SAO PAULO-PARANA/SANTA CATARINA IN SOUTHERN BRASIL...A 1016
HPA LOW AT 29S 53W TO SOUTHEAST PARAGUAY. A RIDGE TO THE SOUTH
CENTERS ON TWO HIGHS...A 1021 HPA HIGH AT 33S 52W AND A 1019 HPA
HIGH AT 27S 39W.


BALBINO...INMET (BRASIL)
DIAZ...INUMET (URUGUAY)
DAVISON/GALVEZ...WPC (USA)