Model Explorer

Four models over one small, very vertical country, drawn on one frame and one colour scale so they can be read against each other. ICON-CH1 is MeteoSwiss's own 1 km ensemble — the only model here that resolves a Swiss valley — with a fresh run every three hours out to 33. ICON-CH2 carries the same physics to five days. ICON-EU is DWD's 7 km regional run, and IFS is ECMWF at its native 9 km, which is what takes the site past day five.

Every model is corrected onto the same 1 km terrain before it is drawn. Raw, they disagree about where the ground is by up to 1,800 m — ECMWF puts Zermatt's valley floor at 2,903 m where the truth is 1,608, and draws it seven degrees too cold as a result. Flipping between untreated models would mostly show their orography. Corrected, a difference between the tabs is a real disagreement about the weather.

Switching model holds the valid time, not the forecast hour. ICON-CH1 runs eight times a day where IFS runs four, so +12 h on one is rarely +12 h on the other; matching the instant is the only comparison that means anything.

Four fields here exist because this is Switzerland. The snow line and the SWISS12 storm index are computed by MeteoSwiss and shipped in its open data — not a freezing level with an offset applied. Föhn and inversion are derived here. Colour ramps are pinned to absolute values, so a loop shows real intensity changes rather than a palette re-fitting itself each frame. For warnings, MeteoSwiss is always the authority.