Storm Forecast
Valid: Thu 29 Jun 2006 06:00 to Fri 30 Jun 2006 06:00 UTC
Issued: Wed 28 Jun 2006 21:15
Forecaster: GATZEN

SYNOPSIS

East of northern Atlantic low geopotential ... African subtropic high ridges into Balkans and eastern Europe. A deep SW-erly flow is present at the western flank of this ridge from western Mediterranean to Alpine region. A short-wave trough embedded in the flow is expected over Alpine region during the period. Later ... this short-wave trough is expected to cut off due to strong WAA/increasing geopotential height over northern/central Europe east of appearing strong northern Atlantic trough. At lower levels ... very unstable airmass ... with high boundary layer moisture and EML aloft ... is present from northern Mediterranean to Balkan region ... where CAPE locally reaches more than 3000 J/kg as indicated by latest soundings. Cooler airmass is present over northwestern Europe.

DISCUSSION

Alpine region, Czech Republic, northern Balkans and Italy

Unstable and warm airmass is present over northern Balkans that is expected to advect into eastern Alpine region during the next hours. GFS expect several 100 J/kg CAPE over southeastern Germany in the morning hours. Ahead of approaching short-wave trough ... strong QG forcing is expected due to strong WAA from the east at low levels and strong DCVA at the cyclonic flank of intense mid-level southerly jet streak pointing towards eastern Alps. Given quite weak CIN and rich low-level moisture ... quick initiation and formation of an MCS is expected over Bavaria by latest GFS. Current thinking is that convective debris/clouds should inhibit strong insolation on Thursday ... and isolated cells should cluster rather quick. Due to strong vertical wind shear ... with northerly low-level winds, easterly at the 850 hPa level ... and southerly at the 500 hPa level ... embedded supercells are forecast ... capable of producing isolated large hail and severe wind gusts. Low LCL heights and increasing LLS should also enhance the chance for tornadoes. MCS should move eastward into Austria/Czech Republic and should intensify given strong inflow of unstable airmass ... and formation of a large MCS/MCV should be possible. Severe wind gusts should be the most severe threat, while large hail and a few tornadoes may occur with any embedded supercell that forms. Intense precip and flash flooding should be likely. To the east of the system ... widespread initiation can also be expected along old outflow boundaries as upper jet streak approaches. Increasing vertical wind shear may be favorable for supercells capable of producing large or very large hail and severe wind gusts. Tornadoes may also occur with isolated storms.

Southwestern Germany

Underneath the short-wave trough ... weak winds and rich low-level moisture are expected. Due to low-level CAPE ... chance for weak tornadoes should be enhanced ... and a couple of events is expected.