Schweizer Sturmforum

Janine hat geschrieben:Dann hol ich meine Pflanzen wohl doch lieber mal vom Fenstersims runter...
Bin jedenfalls gespannt, obs wirklich so heftig wird wie prognostiziert. Ich kann mich nur an das halten, was ihr im Forum schreibt und Meteo Schweiz und Co sagt. Meine Gabe Wetterkarten zu lesen ist leider gleich null

David(Goms) hat geschrieben:Im Oberwallis grossflächig anhaltend mässiger- und nun auch starker Schneefall bis ganz runter (600müM.). Wird wohl noch ein Weilchen so sein...

DISCUSSION

... France, Switzerland, Germany, Austria, Hungary and Slovakia...

We expect no DMC within the broad warm sector of that low, supported by forecast sounding data given deep WAA regime. This may keep the most extreme wind gusts off the surface.

The focus then shifts to the cold front, which is aligned in a more SW-NE manner over France and more from N-S over S-Germany and NE-Austria. Strong dynamics and rapid cooling of the mid-levels may assist in a forced line (probably LEWP-like) of convection along the cold front, which races SE-wards (S-France) and E-wards (S-Germany). However at least over S-Germany the structure of that cold front does not look so impressive right now as does the pressure tendency field in the model field. Nevertheless, not much mixing will be needed to bring damaging wind gusts down to the surface as winds at 850 hPa remain in the range of roughly 30 m/s. Any line-up of convection (even short-line segments) will be able to produce similar wind gusts at the surface! Also, some moisture pooling along that front is still forecast, which may assist in enough LL CAPE for an isolated tornado event. We excluded S-Germany and parts of Austria from a thunderstorm area, as BL moisture seems to be very sparse in forecast model fields. Hence, confidence in electrified convection is limited. However, this does not limit the risk of damaging surface wind gusts as described above.

Of some concern is also an area, covering Hungary and Slovakia during the evening hours onwards. As the cold front approaches from the west, it taps into better moisture, which becomes advected from the N-Adriatic Sea/NE Italy. Some discrepancies exist regarding timing and placement of that front/moisture tongue overlap, but this configuration may result in better prefrontal CAPE build-up. Hence the low prob. thunderstorm area was expanded well to the NE. With diffuse forcing and a messy wind field, coverage of thunderstorms remains questionable. Strong to severe wind gusts will be the primary hazard.