405  
FXSA20 KWBC 011440  
PMDSA  
 
SOUTH AMERICA SYNOPTIC DISCUSSION - INTERNATIONAL DESKS  
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD  
940 AM EST THU FEB 01 2018  
 
GFS DATA AT FTPPRD.NCEP.NOAA.GOV/PUB/DATA/NCCF/COM/GFS/PROD/  
 
SYNOPSIS (VALID FROM FEB 01 AT 0000 UTC): AT 200 HPA...A BROAD BUT  
WELL DEFINED CELL OF THE SUBTROPICAL RIDGE CENTERS OVER NORTHERN  
PARAGUAY AND SOUTHWESTERN MATO GROSSO DO SUL...TO THE SOUTH OF ITS  
CLIMATOLOGICAL POSITION. THS RIDGE IS VENTILATING CONVECTION  
ESPECIALLY ALONG ITS NORTHEASTERN AND WESTERN PERIPHERY...WHERE  
DEEP-LAYER INSTABILITY IS PRESENT. IN THE NROTHEASTERN  
PERIPHERY...WIDESPREAD DEEP CONVECTION IS OCCURRING IN MATO  
GROSSO...RONDONIA AND SOUTHERN AMAZONAS IN BRASIL. LESS ORGANIZED  
CONVECTION IS OCCURRING IN PARA/MARANHAO/TOCANTINS. IN THE WESTERN  
PERIPHERY...SCATTERED TO WIDESPREAD CONVECTION IS OCCURRING IN THE  
ALTIPLANO AND MOST OF BOLIVIA AND THE CHACO. FURTHERMORE...AT LOW  
AND MID-LEVELS...THE SOUTH ATLANTIC CONVERGENCE ZONE HAS ORGANIZED  
AND EXTENDS FROM NORTHERN ESPORITO SANTO IN BRASIL ACROSS SOUTHERN  
GOIAS...MATO GROSSO DO SUL INTO THE NORTHERN CHACO.  
 
THE 250 HPA JET ANALYSIS SHOWS THE SOUTHERN POLAR JET EXTENDING  
ALONG 50S 120W...54W 112W...60S 100W...59S 87W...EXITING AT 54S  
72W. IT REFORMS AT 45S 41W ALONG A 1390KT MAXIMA AT 52S  
34W...EXITING AT 56S 21W. THE NORTHERN POLAR JET EXTENDS ALONG 47S  
120W ALONG A 155KT MAXIMA AT 52S 109W...55S 99W...A 149KT MAXIMA  
AT 56S 87W...50S 72W...49S 61W...A 123KT MAXIMA AT 46S 56W...42S  
46W...46S 35W...51S 26W...EXITING AT 51S 17W. THE SUBTROPICAL JET  
FORMS A BRANCH ALONG THE SOUTHERN PERIPHERY OF THE BOLIVIAN  
HIGH/SUBTROPICAL RIDGE...STARTING AT 22S 78W...ALONG 31S 74W...37S  
62W...A 137KT MAXIMA AT 37S 51W...30S 41W...EXITING AT 20S 41W.  
THE SUBEQUATORIAL JET EXTENDS ALONG12S 109W ALONG 10S 99W...05S  
89W...EXITING AT 01S 77W.  
 
AT 500 HPA...IN THE SOUTHERN STREAM...A TROUGH CENTERS ON A LOW AT  
58S 120W IN THE SOUTHEASTERN PACIFIC...WHILE ANOTHER TROUGH  
CENTERS ON A LOW AT 58S 42W IN THE SOUTH ATLANTIC. BETWEEN THESE  
SYSTEMS...A SUBTLE RIDGE EXTENDS FROM 90W TO 45W AND TO THE SOUTH  
OF 50S. A TIGHT BELT OF WESTERLIES EXTENDS TO THE NORTH OF THESE  
SYSTEMS...ENTERING THE CONTINENT BETWEEN 46S AND THE DRAKE  
PASSAGE. IN THE NORTHERN STREAM...A TRAIN OF HIGHS EXTENDS FROM  
38S 83W...29S 68W...INTO SOUTHEASTERN PARAGUAY. TO THE EAST...A  
TROUGH EXTENDS ALONG 40W FROM 32S NORTH INTO NORTHERN BAHIA AT 20S.  
 
AT LOW LEVELS...A 962 HPA OCCLUDED LOW CENTERS AT 63S 88W...AND  
EXTENDS A FRONT INTO A 972 HPA OCCLUDED LOW AT 60S 76W...A 982 HPA  
LOW AT 56S 71W...A 986 HPA TRIPLE POINT LOW AT 55S 67W...AND A  
FRONT ALONG 52S 70W....52S 77W...A 996 HPA LOW AT 53S 79W...50S  
79W...49S 85W. A 1029 HPA HIGH CENTERS AT 37S 84W AND EXTENDS AN  
AXIS TO THE SOUTHEAST INTO ISLA CHILOE IN CHILE. A 1017 HPA POLAR  
HIGH CENTERS AT 40S 58W OFF THE COAST OF MAR DEL PLATA IN  
ARGENTINA. A FRONT EXTENDS ALONG A 1012 HPA LOW AT 43S 38W...40S  
43W...38S 52W...37S 63W. A FRONT EXTENDS ALONG A 1010 HPA LOW AT  
34S 32W...31S 34W...A 1010 HPA LOW AT 28S 38W...25S 37W...AND AN  
ILL-DEFINED BOUNDARY INTO EASTERN RIO DE JANEIRO. THE SOUTH  
ATLANTIC CONVERGENCE ZONE SACZ EXTENDS FROM 25S 37W ALONG 20S  
40W...17S 49W...22S 58W. SCATTERED DEEP CONVECTION WAS OCCURRING  
ALONG AND TO THE NORTH OF THE SACZ ACROSS ESPIRITO SANTO/SOUTHERN  
BAHIA...MINAS GERAIS...WESTERN MATO GROSSO DO SUL AND  
PARAGUAY/BOLIVIA.  
 
POMIER...SENAMHI (BOLIVIA)  
BALBINO...INMET (BRAZIL)  
DAVISON/GALVEZ...WPC (USA)  

 
 
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