487  
FXSA20 KWBC 071417  
PMDSA  
 
SOUTH AMERICA SYNOPTIC DISCUSSION - INTERNATIONAL DESKS  
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD  
917 AM EST THU DEC 07 2017  
 
GFS DATA AT FTPPRD.NCEP.NOAA.GOV/PUB/DATA/NCCF/COM/GFS/PROD/  
 
SYNOPSIS (VALID FROM DEC 07 AT 0000 UTC): AT 200 HPA...THE  
SUBTROPICAL RIDGE CONTINUES WELL ESTABLISHED WHILE CENTERING A  
HIGH OVER MATO GROSSO AND EXTREME EASTERN BOLIVIA. THE RIDGE  
EXTENDS AN AXIS TO THE EAST ACROSS SOUTHERN BAHIA. THIS IS  
VENTILATING CONVECTION OVER MINAS GERAIS/GOIAS AND SOUTHERN BAHIA.  
THE RIDGE ALSO EXTENDS AN AXIS TO THE NORTHWEST ACROSS NORTHERN  
BOLIVIA...NORTHERN PERU. THIS IS VENTILATING CONVECTION ACROSS THE  
WESTERN AMAZON. ALSO...VENTILATION IN THE NORTHERN FLANK OF THE  
BOLIVIAN HIGH...ACROSS WESTERN AMAZONAS-BRASIL INTO THE COLOMBIAN  
AMAZON IS FAVORING PERSISTENT DEEP CONVECTION...IN A PRECIPITABLE  
WATER POOL THAT EXCEEDS 60MM...AND IN THE CONVERGENT REGION OF THE  
LOW-LEVEL JET OF COLOMBIA AND VENEZUELA.  
 
THE 250 HPA JET ANALYSIS SHOWS THE SOUTHERN POLAR JET EXTENDING  
ALONG 55S 120W...58S 107W...55S 82W...54S 66W...50S 52W...50S  
36W...EXITING AT 43S 20W. THE NORTHERN POLAR JET FORMS AT 45S 112W  
ALONG A 121KT MAXIMA AT 50S 89W...46S 60W...46S 50W...48S  
39W...EXITING AT 41S 22W. THE SUBTROPICAL JET FORMS AT 22S 77W  
ALONG 31S 58W...24S 28W...30S 15W...41S 01W.  
 
AT 500 HPA...IN THE SOUTHERN STREAM...A TRAIN OF LOWS EXTENDS FROM  
THE BELLINGSHAUSEN SEA INTO THE WEDDELL SEA. ONE CENTERS AT 70S  
95W...ANOTHER AT 67S 57W...AND ANOTHER AT 60S 48W. THESE LOWS ARE  
ASSOCIATED WITH TROUGHS THAT ARE EMBEDDED IN A TIGHT BELT OF  
WEST-SOUTH WESTERLIES THAT EXTENDS TO THE SOUTH OF 48S. ONE SHORT  
WAVE TROUGH EXTENDS ALONG 82W...AND ANOTHER ALONG 50W NORTH INTO  
40S. IN THE NORTHERN STREAM...A WEAK LOW CENTERS AT 30S 87W AND  
EXTENDS A BROAD TROUGH OFF THE COAST OF CENTRAL CHILE...FROM 90W  
TO 70W AND TO THE SOUTH OF 22S. ANOTHER BROAD TROUGH EXTENDS  
ACROSS THE RIO DE LA PLATA FROM 38S 55W NORTHWEST INTO 30S 62W.  
 
AT LOW LEVELS...A 970 HPA OCCLUDED LOW CENTERS AT 70S 97W AND  
EXTENDS A FRONT ALONG A 980 HPA LOW AT 68S 76W. THIS EXTENDS A  
FRONT ALONG 65S 75W...A 982 HPA LOW AT 64S 90W...58S 92W...54S  
109W. A 994 HPA OCCLUDED LOW CENTERS AT 55S 83W AND EXTENDS A  
FRONT INTO A 996 HPA TRIPLE POINT LOW AT 54S 80W...AND A FRONT  
ALONG 50S 80W...48S 86W...A 1016 HPA LOW AT 47S 88W...42S 95W. A  
1033 HPA HIGH CENTERS AT 36S 104W. TO THE EAST...A 1017 HPA POLAR  
HIGH CENTERS AT 45S 64W. A 970 HPA OCCLUDED LOW CENTERS AT 59S 47W  
AND EXTENDS A FRONT ALONG A 974 HPA TRIPLE POINT LOW AT 60S  
38W...55S 37W...A 982 HPA LOW AT 51S 41W...47S 43W...A 1000 HPA  
LOW AT 45S 48W...39S 56W...37S 62W. A 1021 HPA HIGH CENTERS AT 33S  
35W. A FRONT EXTENDS ALONG 29S 47W INTO A 1010 HPA LOW AT 35S  
50W...30S 53W...30S 59W.  
 
OVIEDO...SHN (ARGENTINA)  
POMIER...SENAMHI (BOLIVIA)  
RIVAS...SENAMHI (PERU)  
DAVISON/GALVEZ...WPC (USA)  

 
 
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