The Mesoscale Alpine Programme (MAP) included a dense rawinsonde network between Milano and Munich across the Alps. They were partly routinely, partly dedicated soundings. The mostly three to six hourly data during Intensive Observing Periods were used to analyse the vertical structure of the atmosphere up- and downstream of the main Alpine crest.

First a foehn classification scheme was developed (see abstract: Physically based foehn detection) and applied between 7 September and 16 November 1999 (MAP-SOP) to a station in the middle of the Wipp valley well exposed to southerly flows.

With the additional knowledge of wind directions above the main Alpine crest,the whole foehn cycle is split up into pre-, shallow, deep and post foehn periods.

For each of these classes the spatial and temporal development and evolution of the foehn layer is analysed with emphasis on the height, strength and frequency of the topping foehn inversion, flow speeds and layer height. Layers of strong wind shear are identified and their connection to inversions is investigated. From the deduced parameters Froude number estimates are given.

Interesting and persisting local features like cold pools and typical flows near the surface are explained as well.