225  
FXSA20 KWBC 051442  
PMDSA  
 
SOUTH AMERICA SYNOPTIC DISCUSSION - INTERNATIONAL DESKS  
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD  
941 AM EST MON FEB 05 2018  
 
GFS DATA AT FTPPRD.NCEP.NOAA.GOV/PUB/DATA/NCCF/COM/GFS/PROD/  
 
SYNOPSIS (VALID FROM FEB 05 AT 0000 UTC): AT 200 HPA...A HIGH OVER  
NORTHERN CHILE ANCHORS A RIDGE THAT EXTENDS NORTH-TO-SOUTH OVER  
THE CONTINENT BETWEEN 80W-60W. THIS SUSTAINS THE NORTHWARD  
AMPLIFICATION OF A TROUGH ACROSS SAO PAULO IN BRASIL TO MATO  
GROSSO. THIS TROUGH FAVORS AN UPPER DIVERGENT PATTERN ACROSS  
NORTHEAST BRASIL THAT IS VENTING ORGANIZED DEEP CONVECTION ALONG  
THE SOUTH ATLANTIC CONVERGENCE ZONE AND THE NEAR EQUATORIAL TROUGH  
OVER NORTHEAST SOUTH AMERICA. THE RIDGE ALOFT IS ALSO VENTING  
CONVECTION ACROSS PARA-AMAZONAS IN BRASIL TO NORTHERN PERU.  
 
AT 250 HPA...THE SOUTHERN POLAR LIES ALONG 56S 120W...56S  
106W...EXITING AT 57S 89W. IT REFORMS AT 55S 78W...THEN ALONG 60S  
55W...A 154KT MAXIMUM AT 57S 28W...EXITING AT 47S 08W. THE  
NORTHERN POLAR HAS A FINGER THAT EXTENDS BETWEEN 46S 61W AND 36S  
100W. IT REFORMS AT 34S 97W...THEN ALONG 42S 88W...A 154KT MAXIMUM  
AT 52S 74W...A 153KT MAXIMUM AT 56S 59W...53S 38W...AND 42S 11W.  
THE SUBTROPICAL JET HAS ITS ENTRANCE AT 22S 81W...THEN ALONG 37S  
81W...41S 70W...37S 60W...29S 54W...22S 54W...EXITING AT 17S 57W.  
IT REFORMS AT 15S 50W...THEN ALONG 20S 50W...26S 39W...29S  
32W...35S 24W...AND 36S 11W. THE SUBEQUATORIAL JET HAS A FINGER AT  
200 HPA THAT EXTENDS ALONG 01N 107W...02N 101W...EXITING AT 02N  
95W. AT 150 HPA ANOTHER FINGER TO THE SOUTH EXTENDS ALONG 08S  
114W...09S 105W...09S 95W...EXITING AT 10S 88W.  
 
AT 500 HPA...BROAD TROUGH ON THE SOUTHERN STREAM EXTENDS BETWEEN  
140W-90W AND TO THE SOUTH OF 50S. THIS IS PHASING WITH A NORTHERN  
STREAM TROUGH THAT EXTENDS FROM SOUTHERN CHILE/TIERRA DEL  
FUEGO...ALONG 50S 85W...A CYCLONIC MAXIMA AT 43S 95W...TO 30S  
110W. A RIDGE TO THE NORTH...MEANWHILE...EXTENDS ACROSS  
CENTRAL/NORTHERN CHILE TO CENTRAL-NORTHERN ARGENTINA. THIS FAVORS  
A MID LEVEL CONVERGENT PATTERN THAT IS INHIBITING CONVECTION OVER  
CENTRAL-NORTHERN ARGENTINA. IT HOWEVER...IS NOT STRONG ENOUGH TO  
SUPPRESS CONVECTION ALONG THE CENTRAL-NORTHERN ANDES.  
 
AT LOW LEVELS...BROAD TROUGH ON THE SOUTHERN STREAM ANCHORS ON AN  
OCCLUDED 950 HPA LOW AT 62S 103W. THIS EXTENDS A FRONT ALONG A 958  
HPA LOW AT 61S 95W...57S 96W...56S 98W...A 970 HPA LOW AT 55S  
103W...50S 110W...50S 120W...A 1006 HPA LOW AT 51S 125W...AND 48S  
131W. ANOTHER FRONT TO THE NORTH EXTENDS ALONG A 994 HPA LOW AT  
55S 55W...52S 59W...50S 65W...A 1002 HPA LOW AT 50S 71W...47S  
72W...46S 75W...44S 83W...A 1010 HPA LOW AT 40S 88W...35S  
91W...32S 98W...TO A 1014 HPA LOW AT 33S 102W. A RIDGE TO THE  
NORTH CENTERS ON A 1019 HPA HIGH AT 33S 82W AND 1017 HPA HIGH AT  
21S 106W. FARTHER EAST...OVER THE ATLANTIC...AN OLD BOUNDARY  
EXTENDS ALONG A 1010 HPA LOW AT 49S 46W...46S 47W...45S 51W...A  
1006 HPA LOW AT 47S 57W...TO LA PAMPA IN ARGENTINA...WHERE IT  
FAVORS ISOLATED TO SCATTERED DEEP CONVECTION. A RIDGE TO THE NORTH  
CENTERS ON A 1021 HPA HIGH AT 37S 41W. NORTH OF THIS RIDGE...A  
FRONT LIES ALONG A 1018 HPA LOW AT 34S 22W...31S 23W...30S 27W...A  
1014 HPA LOW AT 31S 33W...28S 31W...26S 33W...TO SAO PAULO IN  
BRASIL.  
 
BALBINO...INMET (BRASIL)  
POMIER...SENAMHI (BOLIVIA)  
DAVISON/GALVEZ...WPC (USA)  

 
 
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