920  
FXSA20 KWBC 191448  
PMDSA  
 
SOUTH AMERICA SYNOPTIC DISCUSSION - INTERNATIONAL DESKS  
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD  
947 AM EST FRI JAN 19 2018  
 
GFS DATA AT FTPPRD.NCEP.NOAA.GOV/PUB/DATA/NCCF/COM/GFS/PROD/  
 
SYNOPSIS (VALID FROM JAN 19 AT 0000 UTC): THE 200 HPA ANALYSIS  
SHOWS THE BOLIVIAN HIGH CENTERS ON A HIGH OVER SOUTHWESTERN  
BOLIVIA AND EXTENDS A ZONAL AXIS FROM 20S 100W...ACROSS NORTHERN  
CHILE/SOUTHERN BOLIVIA...INTO SAO PAULO-BRASIL. THE HIGH IS  
VENTILATING CONVECTION ALONG ITS PERIPHERY...ESPECIALLY ACROSS  
MATO GROSSO DO SUL-PARANA-SAO PAULO...WHERE INSTABILITY REMAINS  
HIGH...AND OVER THE ALTIPLANO AND PERUVIAN CENTRAL ANDES. THE  
CAVADO DO NORDESTE IS ELONGATED AND EXTENDS FROM BAHIA INTO A LOW  
IN SOUTHERN PARA. THIS IS VENTILATING CONVECTION ALONG ITS  
NORTHERN PERIPHERY IN INTERACTION WITH THE NET...MOSTLY ACROSS  
CENTRAL/NORTHERN PARA AND MARANHAO IN BRASIL.  
 
THE 250 HPA JET ANALYSIS SHOWS THE SOUTHERN POLAR JET EXTENDING  
ALONG A 124KT MAXIMA AT 60S 120W...EXITING AT 47S 112W. IT REFORMS  
AT 50S 108W ALONG 54S 99W...A 152KT MAXIMA AT 59S 87W...A 170KT  
MAXIMA AT 59S 73W...EXITING AT 58S 64W. ANOTHER FINGER REFORMS AT  
62S 51W EXITING AT 53S 43W. THE NORTHERN POLAR JET EXTENDS ALONG  
46S 120W...45S 110W...47S 104W...A 152KT MAXIMA AT 50S 97W...A  
152KT MAXIMA AT 56S 81W...51S 63W. IT REFORMS AT 50S 57W EXITING  
AT 43S 48W. IT REFORMS AT 42S 42W...ALONG A 137KT MAXIMA AT 46S  
33W...EXITING AT 43S 18W. THE SUBTROPICAL JET FORMS AT 39S 116W  
ALONG 43S 105W...48S 93W...50S 78W...EXITING AT 43S 69W. ANOTHER  
BRANCH FORMS AT 30S 85W ALONG 30S 70W...32S 54W...EXITING AT 36S  
41W. IT REFORMS AT 38S 38W ALONG 41S 30W...EXITING AT 39S 20W. THE  
SUBEQUATORIAL JET EXTENDS ALONG 01S 108W ALONG 05N 88W.  
 
AT 500 HPA...A LONG WAVE PATTERN IS PRESENT WITH A TROUGH THAT  
CENTERS ON A LOW AT 66S 108W AND EXTENDS AN AXIS NORTH ALONG  
120W-100W AND TO THE SOUTH OF 38S. TO THE EAST...A RIDGE EXTENDS  
ALONG 90W-75W AND FROM 35S SOUTH INTO 48S. A SHORT WAVE TROUGH  
EXTENDS FROM CENTRAL ARGENTINA INTO A LOW OFF THE COAST OF CENTRAL  
CHILE LOCATED AT 33S 72W. THIS WAS AIDING ISOLATED THUNDERSTORMS  
IN CUYO. A LONG WAVE TROUGH EXTENDS TO THE EAST FROM 60S 38W ALONG  
43S 45W...INTO EASTERN PARANA-BRASIL. THIS IS AIDING WITH  
CONVECTIVE DEVELOPMENT OVER SAO PAULO AND PARANA-BRASIL.  
 
AT LOW LEVELS...A 982 HPA OCCLUDED LOW CENTERS AT 60S 61W AND  
EXTENDS A FRONT ALONG A 998 HPA LOW AT 52S 59W...49S 59W...A 1006  
HPA LOW AT 45S 65W...NORTHERN PATAGONIA AT 40S 69W...42S 74W...AND  
AN ILL-DEFINED BOUNDARY INTO A 1018 HPA LOW AT 45S 78W...43S 86W.  
TWO 1027 HIGHS CENTER OVER THE EASTERN PACIFIC AT 32S 99W AND AT  
37S 84W. A 1013 HPA HIGH CENTERS OVER BAHIA BLANCA. A FRONT  
EXTENDS ALONG A 998 HPA LOW AT 49S 38W...44S 40W...39S 47W...BAHIA  
DE SAN BOROMBON...35S 65W. A TRAIN OF HIGHS EXTENDS ZONALLY NORTH  
OF THIS BOUNDARY...CENTERING ON A 1013 HPA HIGH AT 34S 54W...32S  
60W...AND A 1015 HPA HIGH AT 31S 63W. A 1002 HPA LOW AT 37S 40W  
EXTENDS A FRONT ALONG 35S 39W...31S 41W...29S 45W...PORTO  
ALEGRE...URUGUIAIANA...NORTHERN CHACO IN ARGENTINA. THUNDERSTORMS  
WERE OCCURRING WELL TO THE NORTH OF THIS BOUNDARY ACROSS SAO PAULO  
AND PARANA IN BRASIL.  
 
OVIEDO...SHN (ARGENTINA)  
POMIER...SENAMHI (BOLIVIA)  
DAVISON...WPC (USA)  

 
 
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