594  
FXSA20 KWBC 031429  
PMDSA  
 
SOUTH AMERICA SYNOPTIC DISCUSSION - INTERNATIONAL DESKS  
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD  
928 AM EST WED JAN 03 2018  
 
GFS DATA AT FTPPRD.NCEP.NOAA.GOV/PUB/DATA/NCCF/COM/GFS/PROD/  
 
SYNOPSIS (VALID FROM JAN 03 AT 0000 UTC): AT 200 HPA...AT 200  
HPA...A HIGH OVER BRASIL NEAR 19S 47W EXTENDS A RIDGE WEST ACROSS  
BOLIVIA-SOUTHERN PERU TO THE EASTERN PACIFIC...AND TO THE  
SOUTHEAST ACROSS RIO DE JANEIRO INTO THE ATLANTIC ALONG 30S 30W. A  
TROUGH TO THE NORTH STRETCHES ALONG 08S 30W...00N 40W TO THE  
GUIANAS. THE RIDGE ALOFT IS VENTING DEEP CONVECTION OVER THE  
CONTINENT BETWEEN 05S-20S...WITH MOST INTENSE OVER BAHIA-MINAS  
GERAIS-TOCANTINS/GOIAS AND MATO GROSSO IN BRASIL.  
 
AT 250 HPA...THE JET ANALYSIS SHOWS THE SOUTHERN POLAR WITH  
ENTRANCE AT 49S 118W...THEN ALONG 48S 100W...49S 90W...51S  
84W...53S 78W...49S 66W...EXITING AT 46S 57W. IT REFORMS AT 47S  
49W...ALONG A 125KT MAXIMUM AT 50S 32W...50S 18W...AND 53S 06W.  
THE NORTHERN POLAR LIES ALONG 44S 120W...44S 108W...44S 97W...46S  
85W...48S 76W...44S 65W...EXITING AT 34S 58W. IT REFORMS AT 36S  
51W...ALONG 38S 47W...42S 41W...A 132KT MAXIMUM AT 43S 32W...42S  
24W...44S 15W...AND 48S 02W. THE SUBTROPICAL JET LIES ALONG 39S  
120W...40S 110W...A 143KT MAXIMUM AT 41S 102W...41S 92W...43S  
80W...40S 72W...EXITING AT 32S 69W. IT REFORMS AT 24S 70W...THEN  
ALONG 26S 61W...32S 52W...A 144KT MAXIMUM AT 36S 45W...38S  
33W...38S 25W...EXITING AT 39S 17W. AT 150 HPA...THE SUBEQUATORIAL  
JET LIES ALONG 05S 11W...05S 105W...EXITING AT 04S 99W.  
 
AT 500 HPA...A RIDGE ON THE NORTHERN STREAM LIES OVER THE EASTERN  
PACIFIC WHILE CENTERING ON A CLOSED HIGH AT 30S 103W. SOUTH OF  
THIS RIDGE...A PROGRESSIVE SHORT WAVE TROUGH ON THE SOUTHERN  
STREAM EXTENDS FROM A CLOSED LOW AT 54S 97W TO 40S 95W. THIS IS  
PRESSING AGAINST A SHORT WAVE RIDGE THAT EXTENDS SOUTH ALONG  
77W/78W. FARTHER EAST...A SHORT WAVE TROUGH ON THE SOUTHERN STREAM  
EXTENDS FROM 53S 60W TO RIO DE LA PLATA BASIN/ENTRE RIOS IN  
ARGENTINA. THIS IS PHASING WITH SHORT WAVE TROUGH TO THE NORTH  
THAT EXTENDS FROM 37S 47W TO MATO GROSSO DO SUL IN BRASIL.  
 
A LOW LEVELS...A RIDGE ON THE NORTHERN STREAM DOMINATES THE  
EASTERN PACIFIC WHILE CENTERING ON TWO CLOSED HIGHS...A 1025 HPA  
HIGH AT 33S 103W AND A 1023 HPA HIGH AT 32S 82W. SOUTH OF THIS  
RIDGE...AN OCCLUDED 974 HPA LOW AT 55S 97W ANCHORS A TROUGH OFF  
THE SOUTH COAST OF CHILE. EMBEDDED IN THIS FLOW A POLAR FRONT  
EXTENDS FROM AN OCCLUDED 986 HPA LOW AT 55S 85W...A 998 HPA LOW AT  
49S 80W...46S 79W...43S 79W...A 1010 HPA LOW AT 42S 91W...38S  
92W...AND 37S 107W. FARTHER EAST...AN OCCLUDED 994 HPA LOW AT 48S  
57W EXTENDS A FRONT ALONG 45S 57W... NORTHERN PATAGONIA TO LA  
PAMPA IN ARGENTINA. ANOTHER FRONT TO THE NORTH LIES ALONG A 998  
HPA LOW AT 45S 43W...43S 44W...A 1002 HPA LOW AT 42S 51W...39S  
52W...A 1002 HPA LOW AT 37S 56W TO SAN JUAN IN CENTRAL ARGENTINA.  
THIS FAVORS ISOLATED CONVECTION OVER RIO DE LA PLATA BASIN. A 1005  
HPA HIGH TO THE SOUTH CENTERS NEAR 38S 58W. ON THE NORTHERN  
STREAM...A 1006 HPA LOW AT 39S 21W EXTENDS A FRONT ALONG 35S  
25W...34S 36W...A 998 HPA LOW AT 32S 45W... SOUTHERN SAO PAULO TO  
MATO GROSSO DO SUL. THIS FAVOR SCATTERED DEEP CONVECTION ACROSS  
SOUTHEAST STATES OF BRASIL.  
 
OVIEDO...SHN (ARGENTINA)  
POMIER...SENAMHI (BOLIVIA)  
DAVISON...WPC (USA)  

 
 
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