Storm Forecast
Valid: Fri 01 Jul 2011 06:00 to Sat 02 Jul 2011 06:00 UTC
Issued: Thu 30 Jun 2011 19:42
Forecaster: TUSCHY
A level 1 was issued for parts of Portugal and Spain mainly for isolated large hail. A localized very large hail event is possible.
A level 1 was issued for parts of Italy mainly for large hail with a localized very large hail event possible over central/southern Italy. Strong to severe downbursts are also forecast.
A level 1 was issued for parts of Germany and Austria mainly for an isolated large hail event.
A level 1 was issued for parts of Greece, Bulgaria and Romania mainly for an isolated large hail event.
A level 1 was issued for parts of Belarus, Latvia, Lithuania, Estonia and extreme W-Russia mainly for large hail, severe wind gusts and a few tornado events.
SYNOPSIS
A cold core low drops southeastwards over central Europe and steers a gradually strengthening depression over Belarus to the west. Hot and mostly stable conditions prevail over the Mediterranean.
DISCUSSION
... Extreme W-Russia, Belarus, Latvia, Lithuania and Estonia ...
A strengthening depression over Belarus moves slowly to the west. Ahead and north of this feature a moist, unstable and strongly sheared environment exists...the latter one especially augmented along the warm front and in the broad warm sector. SRH-1 is somewhat enhanced and combined with low LCLs, an augmented tornado risk exists. Otherwise, multicells and isolated supercells pose a risk for large hail and strong to isolated severe wind gusts.
... Germany ...
Cold-core low moves in from the NW during the morning hours and crosses Germany southeastwards during the forecast period. Marginal hail accompanies daytime driven thunderstorm activity (weak shear/~500 J/kg SBCAPE). A few large hail events are possible along 15-25 m/s DLS/CAPE overlap...mainly over SW/S-Germany. After sunset, thunderstorm activity wanes.
... Italy ...
N-Italy will be monitored for moisture recovery before LL cold front finally pushes southwards. WRF-EZ/GFS barely evolve any CAPE, whereas GFS has up to 1000 J/kg SBCAPE just south of the Alps. Shear would be more than adequate for a few large hail events, but current thermodynamic forecasts preclude a level area for now...despite NE-Italy, where EZ and GFS agree at least with somehwat better CAPE.
Further south, over central and southern Italy, more robust CAPE and 15 m/s DLS create a favorable environment for a few large hail events. An isolated very large hail event is well possible with locally up to 20 m/s DLS. Expected coverage remains too low for any upgrading. A few severe downbursts are also expected.
... S-Spain/Portugal ...
Strong WAA occurs downstream of a developing depression over N-Portugal/NW-Spain and another EML plume advects northwards over the area of interest. Weak forcing and stout capping remains present during the day with very slim thunderstorm probabilities. During the night however, geopotential heights drop somewhat with weak forcing moving in from the west, so an isolated thunderstorm can't be ruled out. Large hail will be the main hazard with an isolated very large hail event possible (10-20m/s DLS and steep mid-level lapse rates). A low-probability thunderstorm area within a level 1 was issued for that set-up.
... Greece, parts of Bulgaria and Romania ...
A few large hail events may occur as 15-20 m/s and modest CAPE overlap. A marginal level 1 was issued for that daytime-driven activity.
