In general observed precipitation is significantly weaker than in fronts, or there may be no precipitation at all.
Parameter
Description
Precipitation
No active front: large areas with no precipitation
Modification of old systems: remains of precipitation activity, light rain and drizzle
Upper Level Low: Precipitation at tear - off stage
Temperature
No connection (stationary)
Wind (incl. gusts)
No connection (stationary)
Other relevant information
Example: To the rear of a synoptic scale trough, in the area of northern Spain and SW France.
19 October 2002/06.00 UTC - Meteosat IR image; weather events (green: rain and showers, blue: drizzle, cyan: snow,
red: thunderstorm, yellow: fog, black: no precipitation)