472  
FXSA20 KWBC 081353  
PMDSA  
 
SOUTH AMERICA SYNOPTIC DISCUSSION - INTERNATIONAL DESKS  
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD  
852 AM EST MON JAN 08 2018  
 
GFS DATA AT FTPPRD.NCEP.NOAA.GOV/PUB/DATA/NCCF/COM/GFS/PROD/  
 
SYNOPSIS (VALID FROM JAN 08 AT 0000 UTC): AT 200 HPA...A RIDGE  
OVER NORTHWEST SOUTH AMERICA/EASTERN TROPICAL PACIFIC ANCHORS ON A  
CLOSED HIGH OVER NORTHERN BOLIVIA. A TROUGH TO THE EAST EXTENDS TO  
THE NORTHWEST FROM A CLOSED LOW EAST OF RECIFE IN BRASIL TO THE  
GUIANAS. THE TROUGH FAVORS AN UPPER CONVERGENT PATTERN ACROSS  
NORTHEAST BRASIL WHERE IT IS INHIBITING ORGANIZED DEEP CONVECTION.  
THE RIDGE...MEANWHILE...VENTS DEEP CONVECTION ACROSS NORTHERN SAO  
PAULO-MATO GROSSO TO PARA IN BRASIL...AND IT IS ALSO ENHANCING  
CONVECTION ACROSS ACRE IN WESTERN BRASIL-CENTRAL PERU.  
 
AT 250 HPA...THE SOUTHERN POLAR LIES ALONG 55S 120W...A 148KT  
MAXIMUM AT 54S 116W...53S 104W...EXITING AT 47S 97W. IT REFORMS AT  
47S 93W...ALONG 55S 80W...58S 66W...53S 52W...EXITING AT 46S 46W.  
THE NORTHERN POLAR LIES ALONG 52S 120W...48S 109W...EXITING AT 39S  
100W. IT REFORMS AT 39S 96W...ALONG A 172KT MAXIMUM AT 49S 86W...A  
151KT MAXIMUM AT 53S 70W...50S 58W...44S 51W...EXITING AT 40S 47W.  
THE SUBTROPICAL JET LIES ALONG A 124KT MAXIMUM AT 37S 120W...35S  
110W...33S 101W...37S 93W...46S 81W...48S 71W...EXITING AT 45S  
62W. IT REFORMS AT 38S 55W...ALONG 34S 48W...34S 40W...40S  
25W...AND 46S 134W. AT 175 HPA...THE SUBEQUATORIAL JET HAS ITS  
ENTRANCE AT 14S 44W...THEN ALONG 08S 47W...EXITING AT 03S 48W. A  
FINGER TO THE NORTH EXTENDS BETWEEN 06N 43W AND 06S 33W.  
 
AT 500 HPA...A LONG WAVE TROUGH EXTENDS NORTH FROM A CLOSED LOW AT  
63S 102W...ALONG 50S 95W...40S 97W...TO 30S 100W. IN A SINUSOIDAL  
PATTERN A RIDGE LIES TO THE EAST...WITH AXIS SOUTH ALONG THE ANDES  
OF CHILE/ARGENTINA TO THE DRAKE PASSAGE. DOWNSTREAM FROM THIS  
RIDGE...ANOTHER TROUGH EXTENDS BETWEEN 50W-20W AND TO THE SOUTH OF  
30S.  
 
AT LOW LEVELS...BROAD TROUGH DOMINATES THE FLOW OVER THE SOUTHEAST  
PACIFIC WHILE ORIGINATING ON AN OCCLUDED 962 HPA LOW AT 63S 92W.  
THIS EXTENDS A FRONT ALONG A 962 HPA LOW AT 62S 90W...59S 86W...A  
982 HPA LOW AT 53S 87W...50S 88W...A 990 HPA LOW AT 47S 92W...44S  
91W...A 998 HPA LOW AT 42S 94W...TO 32S 99W. ANOTHER FRONT TO THE  
EAST AND NORTH EXTENDS FROM A 1014 HPA LOW AT 40S 48W...THEN  
ACROSS SOUTHERN BUENOS AIRES-EASTERN PATAGONIA IN ARGENTINA...A  
998 HPA LOW AT 50S 71W...48S 71W...A 990 HPA LOW AT 51S 81W...45S  
80W...A 998 HPA LOW AT 42S 90W...33S 93W...TO A 1014 HPA LOW AT  
27S 108W. A RIDGE TO THE NORTH ANCHORS ON A 1021 HPA HIGH AT 21S  
87W...WHILE ANOTHER RIDGE TO THE EAST ALSO CENTERS ON A 1021 HPA  
HIGH AT 34S 42W. BROAD TROUGH TO THE EAST OF THIS RIDGE CENTERS ON  
AN OCCLUDED 962 HPA LOW AT 55S 27W. THIS EXTENDS A FRONT ALONG A  
988 HPA LOW AT 51S 15W...44S 14W...A 1014 HPA LOW AT 39S 25W...34S  
28W...31S 34W...A 1018 HPA LOW AT 26S 44W... NORTHERN SAO  
PAULO...TO A 1014 HPA LOW AT 27S 53W. THIS SUSTAINS SCATTERED DEEP  
CONVECTION ACROSS SOUTHEAST BRASIL.  
 
OVIEDO...SHN (ARGENTINA)  
POMIER...SENAMHI (BOLIVIA)  
DAVISON...WPC (USA)  

 
 
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