Storm Forecast
Valid: Fri 14 Jul 2006 06:00 to Sat 15 Jul 2006 06:00 UTC
Issued: Thu 13 Jul 2006 19:21
Forecaster: TUSCHY

SYNOPSIS

Intense high pressure area will be placed over the North Sea, moving S/SE-ward very slowly during the next 24 hours.
Downstream of this high pressure area, cool and stable airmass will be advected well towards the south, connected with an amplifying upper-level trough.
Frontal boundary, now separating NW/SE Europe in different airmass types, will continue its S/SE-ward shift and widespread TSTM activity can be expected along this baroclinic zone.

DISCUSSION

...Eastern parts of the Baltic Sea, Lithuania, Latvia, Estonia and southeastern Finland...

Powerful upper-level jet amplification to the point of a beginning cut-off process will occur over this region during the next 24 hours.
Interaction of the upper-level jet distribution and complex frontal behavior should cause a broad area of an enhanced severe TSTM possibility.

The slowly exiting frontal boundary should be well to the south of the area of interest, while a cold front is forecast to arrive during the morning hours.
Thermodynamic environment will become increasingly favorable due to a cool-down of the mid-levels and therefore a steepening of the mid-level lapse rates.
Dew points ( model forecast ) seem to be on track and expect at least marginal instability release of ~100-400 J/kg .
DLS of 20-25m/s and a well mixed boundary - layer should be fine for an enhanced severe wind gust risk.

...Most parts of Poland,the Czech Republic, eastern Austria, Slovakia,Hungary,western Romania and Ukraine and Belarus...

There are signs that an organized line of storms could form over the western part of this broad level-1 area, racing southward with an attendant severe wind gust risk.

Main focus for TSTM initiation will be on the one hand the frontal boundary and on the other hand an area of enhanced upper-level divergence ( as a consequence of a favorable jet configuration with one intense jet, digging southward over Poland and Hungary and another one, departing NE-ward over western Belarus).
A weakly capped and unstable airmass will be present over a broad prefrontal region and scattered to widespread TSTM acitvity can be expected.
Impressive background flow will develop and storms should line up pretty .
Only negative factor could be the well mixed / dried boundary layer and therefore a limited instability release mainly over eastern Austria, Slovakia and Hungary.... but this weak point could easily be balanced by the strong DLS....
Main threat will be severe-damaging wind gusts ( especially if storms bow out ) and isolated large hail...an upgrade will become necessary, if indeed more instability/higher dewpoints can develop than expected.

An increase in the low-level shear and lowering LCLs should also be favorable for an isolated tornado report, mainly over eastern Poland and western Belarus.

The rest of the European TSTM area will see mainly diurnal driven TSTMs with basically sub-severe weather conditions.

...Northern Morocco...

Kinematic environment would be favorable for organized storms but right now, confidence of severe TSTM development ( and its coverage) wil be too low for highlighting the area with a level-1.

Very warm 850hPa temperatures will be present but steep mid-level lapse rates strong diabatic heating should cause a few storms to penetrate the cap mainly along the northern coast of Morocco, where mountainous area should support a few storms to develop.
TSTMs will stay elevated with an attendant large hail risk ... the area will be monitored in case of higher storm coverage than expected.