201  
FXSA20 KWBC 241336  
PMDSA  
 
SOUTH AMERICA SYNOPTIC DISCUSSION - INTERNATIONAL DESKS  
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD  
936 AM EDT TUE OCT 24 2017  
 
GFS DATA AT FTPPRD.NCEP.NOAA.GOV/PUB/DATA/NCCF/COM/GFS/PROD/  
 
SYNOPSIS (VALID FROM OCT 24 AT 0000 UTC): AT 200 HPA...A HIGH NEAR  
03S 110W ANCHORS A BROAD RIDGE THAT EXTENDS TO 85W AND TO THE  
NORTH OF 25S. ANOTHER RIDGE TO THE EAST EXTENDS OVER THE CONTINENT  
TO THE NORTH OF 20S...WITH A SHORT WAVE TROUGH ALONG 79W  
SEPARATING THESE RIDGES. UNDER INFLUENCE OF THIS TROUGH...AND THE  
RIDGE OVER THE CONTINENT...ORGANIZED CONVECTION WAS CLUSTERING  
OVER NORTHWEST SOUTH AMERICA.  
 
THE UPPER JET ANALYSIS SHOWS THE SOUTHERN POLAR JET ALONG 68S  
95W...55S 92W...48S 69W...A 124KT MAXIMA AT 59S 56W...EXITING AT  
65S 41W. THE NORTHERN POLAR JET EXTENDS ALONG 46S 120W...49S  
109W...47S 95W...EXITING AT 43S 85W. ANOTHER BRANCH FORMS AT 34S  
103W EXITING AT 28S 117W. IT REFORMS AT 28S 111W ALONG 32S  
105W...EXITING AT 32S 93W. IT REFORMS AT 33S 85W ALONG 34S  
76W...EXITING AT 34S 65W. IT REFORMS AT 31S 50W ALONG 31S 38W...A  
153KT MAXIMA AT 38S 28W...42S 17W. THE SUBTROPICAL JET FORMS AT  
22S 66W ALONG 24S 48W...29S 36W...39S 19W. THE SUBEQUATORIAL JET  
EXTENDS ALONG 11S 117W...16S 106W...16S 91W...07S 85W...EXITING AT  
0 86W  
 
AT 500 HPA...BROAD TROUGH EXTENDS NORTH FROM THE ANTARCTIC  
PENINSULA/DRAKE PASSAGE TO THE SOUTHERN CONE OF SOUTH AMERICA.  
THIS IS FOCUSING SHORT WAVE ENERGY ACROSS SOUTHERN/CENTRAL CHILE  
INTO ARGENTINA. FARTHER EAST...IN A SPLIT FLOW PATTERN...THE FLOW  
DIVIDES BETWEEN A RIDGE ON THE SOUTHERN STREAM AND A TROUGH TO THE  
NORTH. THE RIDGE EXTENDS SOUTH OF 50W AND ALONG 35W. THE TROUGH TO  
THE NORTH...MEANWHILE...EXTENDS BETWEEN 50W-28W WHILE ANCHORING ON  
A CLOSED LOW AT 40S 35W.  
 
THE SURFACE ANALYSIS SHOWS A 976 HPA OCCLUDED LOW AT 59S 66W  
EXTENDING A FRONT ALONG 57S 64W...54S 70W NEAR USHUAIA. A 978 HPA  
OCCLUDED LOW CENTERS AT 66S 57W AND EXTENDS A FRONT ALONG 68S  
52W...A 992 HPA TRIPLE POINT LOW AT 65S 42W...61S 44W...58S  
48W...A 988 HPA LOW AT 58S 52W...56S 52W...54S 56W...A 988 HPA LOW  
AT 53S 59W...49S 59W...46S 62W...A 1002 HPA LOW AT 44S 65W...43S  
68W...44S 71W...A 1014 HPA LOW AT 43S 77W...39S 80W. A FRONT  
EXTENDS ALONG 45S 56W...A 1002 HPA LOW AT 44S 62W...39S 64W...38S  
68W...AND AN ILL-DEFINED BOUNDARY ALONG A 1014 HPA LOW AT 38S  
71W...33S 78W. RAINFALL WAS BEING REPORTED IN SOUTHERN CHILE AND  
PARTS OF PATAGONIA. A 1002 HPA OCCLUDED LOW CENTERING AT 40S  
35W...AND EXTENDING AN OCCLUDED FRONT ALONG 32S 36W...30S  
44W...36S 51W. A FRONT EXTENDS ALONG A 1014 HPA LOW AT 38S  
25W...32S 26W...29S 31W...A 1018 HPA LOW AT 28S 34W...25S  
35W...23S 38W...A 1018 HPA LOW AT 23S 40W...20S 43W...21S  
47W...23S 53W...24S 58W...26S 63W.  
 
VANNUCCI...SMN (ARGENTINA)  
RIVAS...SENAMHI (PERU)  
DAVISON/GALVEZ...WPC (USA)  

 
 
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