Voorzover je alleen op radarbeelden kunt (of mag) oordelen. 
As their name suggests, NCFRBs are noticeably narrow, with the distance measured perpendicular to the line as small as one to two kilometers. Narrow cold-frontal rainbands form along a surface cold front where there's a noticeable shift in wind direction. For confirmation, check out the NAM model analysis of 1000-mb streamlines at 12Z on January 30, 2013 (above; larger image). Updrafts in narrow cold-frontal rainbands can be intense, with speeds reaching 10 meters per second (about 22 mph) at relatively low altitudes (one kilometer or so). Despite these speedy updrafts in the lower troposphere, the depth of the convection is, on average, three kilometers.
Bron: https://www.wunderground.com/blog/24hourprof/narrow-coldfrontal-rainbands.html
LEWP's worden toch meer geassocieerd met zware convectie en met name het optreden van 'bow echo's' in de buienlijn is iets wat bij LEWP's voorkomt: https://en.wikipedia.org/wiki/Line_echo_wave_pattern
*Noot voor de liefhebbers/vededigers vna de Nederlanse taal: helaas zijn er mij geen Nederlandse vertalingen van beide Engelse vaktermen bekend...