Commas can be split into a head and a tail, whereby the head clouds are layered cloudiness with dynamical precipitation and the tail clouds are more convective cloudiness with showery precipitation.

Parameter	Description
Precipitation (incl. thunder)	Moderate to heavy precipitation, rain or snow, in Comma head In Comma tail more showery precitation In Comma tail quite often hail and thunderstorms are observed.
Temperature	Surface temperature and sea surface temperature are forcing features of convection.
Wind (incl. gusts)	In surface trough strong winds can be expected. Ahead of the Comma head strong gusts are common. In and near showers also strong gusts can be observed.
Other relevant information	Risk of moderate to severe icing and turbulence Poor visibility during heavy snowfall Heavy snow fall can cause hazardous weather for society Different behaviour over sea and land

In the example from 13 April 1999/06.00 UTC the Comma head extending from N. Ireland to Scotland is accompanied by reports of rain and snow, whilst the Comma tail over central England has fewer reports of precipitation.