Forecast Update
Valid: Sat 17 Jun 2006 09:00 to Sun 18 Jun 2006 06:00 UTC
Issued: Sat 17 Jun 2006 08:31
Forecaster: TUSCHY

SYNOPSIS

Please refer to the outlook, issued at Fri 16 Jun 2006 14:04 UTC !


DISCUSSION

... Poland, the Czech Republic, parts of Slovakia and NE Austria....

Main reason for this update will be a few adjustments to the current outlook.

Model pool showed a slight shift more towards the east in convective precipitation signals and therefore expanded the highlighted areas more towards the east and northeast.

Well defined upper-level disturbance will continue its slow eastward shift and attendant stronger wind field should reach central Poland and the eastern Czech Republic during the next few hours, where instability values in the range of 500-1000 J/kg are forecast....
Still difficult to pinpoint the exact area, where TSTMs will initiate, but the best region looks like to be in the level-2 area ( strong frontal ageostrophic circulation and best moisture convergence).
Steep mid-level lapse rates, combined with ~20m/s DLS and enough instability will be favorable for each storm to produce large hail...even significant hail (>5cm ) can be expected with each more discrete cell.

Further towards the south ( over eastern Austria), DLS , combined with moderate to high instability values, should still be enough for an isolated significant hailstorm, but current thinking its, that the coverage of those events should be too low for an southward expansion of the level-2 area.

....Balearic Islands.....

Strengthening forcing due to a NE-ward moving short-wave and strong DLS favor an upgrade of this area.... Main risk will be a severe wind gust threat.... Initiation should first occur during the early night hours.