Storm Forecast
Valid: Fri 06 Feb 2015 06:00 to Sat 07 Feb 2015 06:00 UTC
Issued: Thu 05 Feb 2015 18:57
Forecaster: TUSCHY

A level 1 was issued for parts of the Aegean Sea mainly for excessive rain and an isolated tornado, severe wind gust and large hail event.

SYNOPSIS

Blocking high-over-low pattern evolves over Europe. An extensive upper low remains anchored over the W/CNTRL Mediterranean while another trough digs south over E/NE Europe. Strong high pressure is situated over Scotland/Ireland.

DISCUSSION

...W/CNTRL Mediterranean ...

The W-E elongated vortex assists in ongoing scattered thunderstorm activity. Overall, the kinematic and thermodynamic environment won't support organized DMC. Still, an isolated better organized event with heavy rain (due to slow storm motions) and a few waterspout reports are well possible ... especially along the coasts of Italy. No focus exists for a level 1 area (including QPFs of numerical guidance).

... Aegean Sea ...

Between 12-00 Z, eastbound surging cold front and prefrontal warm sector will be the foci for better organized thunderstorms. Although the main activity is forecast to occur along the cold front, a few prefrontal storms can't be ruled out along the N-coast of the Aegean Sea. It remains questionable if a weak surface depression is able to evolve over the NW Aegean Sea, which could increase LL shear (that's what GFS offers). Any prefrontal storm will see adequate shear (20 m/s DLS) and 400-800 J/kg MLCAPE for updraft rotation. Hence an isolated large hail and severe wind gust event is possible mainly along the N-Aegean Sea. The tornado risk increases in the same area due to backed LL flow and modest veering above. The severe risk increases a bit with cold front passage (due to higher thunderstorm coverage), although rapid clustering could lower the chance for discrete/longer lived storms. With 20-25 m/s S-erly flow ahead/along the cold front, training becomes a concern which increases the excessive rainfall risk. However, the progressive nature of the front and the rapidly weakening LLJ during the day preclude higher probabilities. Otherwise an isolated large hail and severe wind gust risk will be possible.
The severe risk diminishes from W to E and finally decreases between 21-00 Z over the far NE/E Aegean Sea.