Atmospheric flow pattern, neatly conic in circulation (11)
I believe the answer is:
anticyclone
'atmospheric flow pattern' is the definition.
(weather system)
'neatly conic in circulation' is the wordplay.
'in circulation' indicates anagramming the letters.
'neatly'+'conic'='neatlyconic'
'neatlyconic' anagrammed gives 'ANTICYCLONE'.
(Other definitions for anticyclone that I've seen before include "Circulating weather system" , "High-pressure weather system" , "Swirl in the atmosphere" .)