Upper Level Low - Weather Events

• The frontal cloud band on the leading edge of an Upper Level Low is usually thick enough to produce precipitation. In some cases there is also frontal cloudiness on the rear edge. Within the cloud bands there are embedded cbs, and therefore the precipitation is showery.
• When the Upper Level Low is over land, there is a low cloud layer in the centre.
• Over cold surface there is no convection, and therefore no showers occur.

Over Sea

Parameter	Description
Precipitation	Moderate to heavy showery precipitation. In winter season snow and snow showers are possible Also hail and thunderstorms can occur
Temperature	No changes on the surface
Wind (incl. gusts)	Strong gusts around Cbs
Other relevant information	Risk of moderate to severe icing and turbulence.

On the 15th of September 2005 at 15.00 UTC there is an Upper Level Low partly over southern Portugal.

	15 September 2005/15.00 UTC - Meteosat IR 10.8 image, weather events (green: rain and showers, cyan: snow, yellow: fog and mist, black: no precipitation)

Over Land

Parameter	Description
Precipitation	In summer season: In cloud bands moderate to heavy showery rain In the centre overcast low layered cloudiness with rain or drizzle, sometimes showers Possibly thunderstorms and hail In winter season: In cloud bands showery snow or rain In centre overcast low layered cloudiness possibly with snow, rain or drizzle
Temperature	No changes on the surface
Wind (incl. gusts)	Strong gusts around Cbs
Other relevant information	Risk of moderate to severe icing and turbulence.

An Upper Level Low over Poland on the 8th of June 2005 at 12.00 UTC.

	08 June 2005/12.00 UTC - Meteosat IR 10.8 image, weather events (green: rain and showers, cyan: snow, yellow: fog and mist, black: no precipitation)