336  
FXSA20 KWBC 281337  
PMDSA  
 
SOUTH AMERICA SYNOPTIC DISCUSSION - INTERNATIONAL DESKS  
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD  
836 AM EST TUE NOV 28 2017  
 
GFS DATA AT FTPPRD.NCEP.NOAA.GOV/PUB/DATA/NCCF/COM/GFS/PROD/  
 
SYNOPSIS (VALID FROM NOV 28 AT 0000 UTC): AT 200 HPA...A HIGH OVER  
NORTHERN BOLIVIA EXTENDS A RIDGE TO THE EAST-SOUTHEAST ACROSS MATO  
GROSSO-MINAS GERAIS IN BRASIL TO THE WESTERN ATLANTIC NEAR 22S  
30W. THE RIDGE UNDERCUTS A TROUGH TO THE NORTH THAT EXTENDS ALONG  
15S 30W...10S 37W...TO A CLOSED LOW AT 03S 39W. THE RIDGE ALOFT IS  
VENTING ORGANIZED DEEP CONVECTION ACROSS SOUTHERN PERU-NORTHERN  
BOLIVIA-ACRE/RONDONIA TO MINAS GERAIS IN BRASIL. OTHER CONVECTION  
WAS CLUSTERING OVER EASTERN ECUADOR/SOUTHERN COLOMBIA AND THE  
NORTHERN JUNGLE OF PERU.  
 
AT 250 HPA...THE JET ANALYSIS SHOWS THE SOUTHERN POLAR WITH  
ENTRANCE AT 48S 115W...THEN ALONG 46S 107W...A 130KT MAXIMUM AT  
53S 97W...62S 77W...59S 55W...EXITING AT 55S 42W. THE NORTHERN  
POLAR HAS ITS ENTRANCE AT 44S 120W...THEN ALONG 43S 106W...A 133KT  
MAXIMUM AT 49S 94W...53S 79W...51S 60W...EXITING AT 43S 55W. IT  
REFORMS AT 36S 50W...ALONG 37S 43W...EXITING AT 42S 37W. THE  
SUBTROPICAL JET HAS A BRANCH THAT EXTENDS ALONG 40S 120W...40S  
105W...42S 99W...49S 82W...49S 75W...EXITING AT 46S 72W. IT  
REFORMS AT 28S 84W...THEN ALONG 31S 72W...31S 62W...28S 53W...27S  
43W...34S 36W...A 139KT MAXIMUM AT 38S 31W...EXITING AT 44S 23W.  
THE SUBEQUATORIAL JET HAS A FINGER TO THE NORTH THAT EXTENDS AT  
150 HPA ALONG 09S 115W...09S 108W...EXITING AT 08S 100W. ANOTHER  
FINGER TO THE NORTH EXTENDS ALONG 05S 111W...03S 105W...EXITING AT  
01S 100W.  
 
AT 500 HPA...A LONG WAVE TROUGH ON THE SOUTHERN STREAM EXTENDS  
FROM 60S 102W...ALONG 50S 107W...40S 110W TO 34S 112W. THE LONG  
WAVE TROUGH IS PRESSING AGAINST A BROAD RIDGE TO THE EAST...WITH  
AXIS ENVELOPING AREA BETWEEN 90W-55W AND TO THE SOUTH OF 40S. A  
SHORT WAVE TROUGH LIES TO THE NORTH OF THIS AXIS...MEANDERING OFF  
THE CENTRAL COAST OF CHILE WHILE CENTERING ON A CLOSED LOW AT 34S  
80W. FARTHER EAST...BROAD TROUGH EXTENDS OVER THE SOUTH  
ATLANTIC...WITH AXIS TO THE NORTHWEST FROM 60S 27W...ALONG 50S  
40W...A CLOSED LOW AT 44S 47W...TO THE SOUTHERN STATES OF  
BRASIL/URUGUAY.  
 
AT LOW LEVELS...A RIDGE ON THE NORTHERN STREAM LIES OVER THE  
EASTERN PACIFIC WHILE ANCHORING ON A 1025 HPA HIGH AT 34S 92W.  
BROAD TROUGH LIES TO THE SOUTH...WITH POLAR FRONTS REVOLVING  
AROUND THIS AXIS. ONE EXTENDS ALONG A 978 HPA LOW AT 60S 41W...57S  
44W...58S 50W...60S 60W...A 970 HPA LOW AT 64S 72W...61S 77W...59S  
86W...A 962 HPA LOW AT 60S 100W...58S 95W...57S 98W...A 972 HPA  
LOW AT 55S 101W...50S 98W...TO 44S 102W. ANOTHER FRONT TO THE  
NORTH EXTENDS ALONG A 978 HPA LOW AT 59S 64W...53S 64W...48S  
71W...49S 76W...A 1002 HPA LOW AT 51S 82W...49S 85W...48S 89W...A  
990 HPA LOW AT 48S 97W...42S 99W...38S 105W...TO A 1018 HPA LOW AT  
35S 110W. OVER THE ATLANTIC...AN ELONGATED FRONT EXTENDS ALONG A  
1002 HPA LOW AT 40S 41W...35S 44W...RIO GRANDE DO SUL-NORTHERN  
URUGUAYCORDOBA IN ARGENTINA-CUYO TO A 1010 HPA LOW AT 36S 72W. A  
POLAR RIDGE TO THE SOUTH CENTERS ON A 1025 HPA HIGH AT 39S 58W.  
ANOTHER FRONT TO THE EAST AND NORTH EXTENDS FROM AN OCCLUDED 986  
HPA LOW AT 44S 33W...A 994 HPA LOW AT 47S 28W...40S 26W...34S  
33W...A 1014 HPA LOW AT 29S 38W...25S 39W...RIO DE  
JANEIRO/SOUTHERN MINAS GERAIS...MATO GROSSO DO SUL TO CHACO  
PARAGUAYO. ORGANIZED DEEP CONVECTION WAS BUILDING ALONG THIS  
BOUNDARY. A 1017 HPA HIGH AT 28S 47W ANCHORS A SHORT WAVE RIDGE  
OVER SOUTHERN BRASIL.  
 
OVIEDO...SHN (ARGENTINA)  
VANNUCCI...SMN (ARGENTINA)  
RIVAS...SENAMHI (PERU)  
DAVISON...WPC (USA)  

 
 
CLICK HERE TO GO TO PREVIOUS BULLETINS.

The Nexlab HPC Page Main Text Page