Forecast Update
Valid: Fri 28 Jul 2006 11:00 to Sat 29 Jul 2006 06:00 UTC
Issued: Fri 28 Jul 2006 10:59
Forecaster: TUSCHY

SYNOPSIS

Please refer to the outlook, issued at Thu 27 Jul 2006 18:04 UTC !

DISCUSSION

Some minor adjustments were made for the TSTM line (SE Europe).

... extreme SE France, N-Italy...

Main reason for upgrading will be the thermodynamic environment, which can be seen on latest 00Z soundings.... Broad area of impressive steep mid-level lapse rates can be found along the N-coast of the Mediterranean area and although this EML is forecast to weaken slightly during the daytime hours, still steep lapse rates should be found over the area of interest.

Latest synop data reports also indicate very high dewpoints (18-26°C ), mainly along the coastal areas, but also well inland over N-Italy... Strong heating and a well mixed boundary layer, combined with those lapse rates should yield moderate to locally high instability values ( Nimes had ~ 2000 J/kg at 00Z ).
Although not impressive, shear will slightly increase during the next 12 hours and should be more than adequate for multicell storm / supercell development.... Each developing storm will pose a risk for large to isolated extremely large hail and severe wind gusts...
The tornado threat should stay low, but can't be neglected ( mainly along developing outflow boundaries ).
Storm coverage may not justify "high coverage" so upgrading was mainly due to expected isolated extremely severe weather events.
An intense TSTM NW of the Balearic Islands developed along an outflow boundary in a very favorable environment.... Also isolated TSTMs now start to develop over extreme SE France.