Forecast Update
Valid: Wed 03 Jan 2007 00:00 to Wed 03 Jan 2007 06:00 UTC
Issued: Tue 02 Jan 2007 23:15
Forecaster: TUSCHY

SYNOPSIS

Please refer to the outlook issued at Mon 01 Jan 2007 19:46 !

DISCUSSION

Main reason for an update is the upgrade of a small are to a level-2 over parts of the Aegean Sea and western Turkey.

Latest WV / IR images indicate that the cold front is on track regarding timing and location. 21Z Synop reports had the wind shift zone somewhere over extreme W / SW Greece with scattered storms moving onshore.
This frontal boundary should rapidly race towards the east, reaching the Aegean Sea at about 00-01Z.
SSTs are pretty warm with 15-16°C ( also confirmed by the TSMS showing a SST of 15°C at Ayvalik and 16°C at Kusadasi ).
12Z soundings are not a big help ( also missing the sounding of Izmir ) because of the rapidly developing LL depression north of Greece. Synop stations over W-Turkey reported constantly 15-20kt southerly winds, which provides dewpoints of 10°C and more along the coastal areas of W-Turkey.

Latest thinking is that the offshore moving cold front will rapidly be activated regarding convective activity due to the warm SSTs and rapidly cooling mid-levels. SBCAPE should be on the lower-end side, but GFS still has up to 200 J/kg in the level-2 area and there are no indications that the model exaggerates.
GFS indicates a weak dry slot, intersecting the cold front over the Aegean Sea, combined with an impressive UVV field.
Kinematic parameters become better due to an approaching 90kt - 500hPa jet with DLS increasing significantly up to 35m/s.
Rapidly steepening mid-level lapse rates and approaching drier air at 700-500hPa will be supportive for an enhanced downward momentum transport, increasing the already strong background flow .
A line of strongly forced storms should develop along the eastward racing cold front and a severe-damaging wind gust threat can be expected, mainly in the level-2 area.
The tornado threat should also increase , especially along the coastal areas of W-Turkey, where LL shear will reach 15-20m/s.
Went a little bit more inland with the TSTM line than GFS, because of the strongly forced nature of this system, but storms should become mostly elevated due to a rapidly cooling PBL further inland. Each storm over Turkey would also have an enhanced large hail risk, but confidence in any significant storm coverage that far inland is too low for reflecting this in higher probabilities.

Modification to the rest of the highlighted areas over Europe were done, too !