Storm Forecast
Valid: Fri 26 May 2006 06:00 to Sat 27 May 2006 06:00 UTC
Issued: Thu 25 May 2006 18:03
Forecaster: TUSCHY

SYNOPSIS

Strong zonal flow will persist over most parts of Europe during the next 24 hours...Broad, but well developed upper-level trough, currently placed over Sweden,Finland and Norway, will be nearly stationary during the forecast period...a few intense impulses of an upper-level jet however will reach the upstream part of this trough and this will help to slowly shift the trough axis towards the east in a more negatively tilted position. This constellation will result in a pretty broad area of at least marginal TSTM development.
The Mediterranean will see dry, hot and stable conditions and no significant TSTM development is expected.

DISCUSSION

...broad area of NE Europe...

Combination of very cold mid-level airmass and steep lapse rates will set the stage for a broad area of low-end to moderate instability release... GFS indicates the advection of a pool of slightly higher boundary layer moisture from central Europe and therefore a slight increase in dewpoints mainly over eastern Poland and the Belarus.
A slowly eastward moving cold front will be the focus for TSTM development and main TSTM activity will develop over NE Poland, Belarus and eastern Lavia during the afternoon hours. DLS in the order of 15m/s will favor a few multicell storms with a marginal hail / severe wind gust risk.

Another areas of enhanced TSTM development will be found over S- Finland, where strong forcing and moderate instability overlap..... and the coastal areas of Lithuania,Latvia and Estonia, but weak shear should bar storms from reaching the severe criteria....Very steep lapse rates and low wet bulb zero levels would though be fine for a marginal hail threat with maturing storms.

...parts of Bulgaria, Turkey and SE Ukraine..

Frontal boundary will finally shift towards the east but parts of eastern Bulgaria, Turkey and
the SE Ukraine will again see scattered TSTMs development .... DLS up to 20m/s will be more than adequate for a few severe wind gust reports, but coverage will be too low for a level 1.

...extreme NE Morocco and NW Algeria...

Broad upper-/low-level depression will affect most parts of NW Africa... Main concern will be a rapid decay of instability over the area of interest, but models indicate still a few hundred J/kg instability during the late evening hours... Kinematic parameters will be favorable for a few organized storms to develop, capable of producing severe wind gusts and large hail....Low LCLs and enhanced LL shear will be present and this would enhance the tornado threat during the evening hours ...but indications are that the main activity will develop outside of the area of responsibility (towards the south ).

..southeast Germany...

Over-all conditions and parameters don't favor any significant TSTM development, but there could be a short time frame for isolated storms to develop along a slowly northeastward moving warm front [ late afternoon - early evening hours ].... GFS indicates a slight increase of lapse rates and the advection of higher dewpoints over most parts of southern and southeastern Germany.
Don't want to exclude an isolated embedded TSTM to develop, but current thinking is that coverage will be too low for even warranting a TSTM line.... Despite the fact whether electrified or not, each TSTM or shower would pose a risk of severe wind gusts given the impressive background wind field.