Geopotential 300 hPa and Airmass RGB, Time Sequence: 3h, 29 February to 01 March 2008     

The geopotential height in 300 hPa reveals a pronounced upper air trough over western Europe. However, more relevant is the Central and West Atlantic: From New Foundland to the area south of Iceland the image reveals almost line-orientated countours with a strong gradient that indicates an intense frontal zone. A short wave trough and divergent isolines can be seen south of Iceland. This is a typical structure during a rapid cyclogenesis.

In the following, we will concentrate upon this short wave trough.

The trough moved fast to the east and intensified.

All systems moved fast to the East. Near the trough's axis we see some convection (South of Iceland).

The short wave trough deepened. Near its axis (southeast of Iceland) we recognise intensifying convection. Over Northwest Scotland (east of the trough's axis). The split front is superimposed by diverging contour lines yielding lifting of the potential instable air and probably shoers or even thunderstorms.

The trough arrived overScotland. Near its axis enhanced convection developed which exhibited the form of a comma.

The intense trough moved fast to the East. Between its axis and forefield convection occured.

The trough's amplitude increased. The dry slot over the southern parts of the Northsea coincided with the contour lines' divergent zone.

The trough continued deepening and seems to broaden to two axis. The west one was orientated to West Scotland, that more to the east arrived already over the east parts of the North Sea and Germany. The zone of divergent isolines extended from Norway to West Germany.

We find two trough's axis (extending to Scotland with a developing convective line) and extending from Norway to Denmark. The latter started to weaken.

One trough's axis moved fast from Scotland to the South and Southeast North Sea and intensified. In its forefield the convective line intensified, too. Rests of the second trough can be found east of Denmark.

The trough arrived over Middle Europe and extended more to the South. East of its axis the convective line intensified (due to positive vorticity advection).

The trough's amplitude growed very fast. The axis extended now from South Sweden to Southwest Germany. In the frontal part and near the axis the convective line reached its maximum intensity.

Convective line and the sharp trough's axis moved fast to the East/Southeast. The axis fits well with the rear edge of the convective line.

The convective line started weakening, according to the weakening trough. A second trough axis can be identified near the Alpine crest (due to orographic effects).

In the meanwhile the long wave trough extended from Sweden to the Adriatic Sea. We still recognise the second trough's axis near the Alpine crest.

The long wave trough continued moving to East. Near its axis convection happened. The trough's axis over the Alps remained stationary what is typically for orographic induced troughs.

The long wave trough continued moving to the East. We still see the second trough near the Alps.