LVL2 setup in N-Italy, N-Balkans

Estofex gave LVL2 for todays setup and I mostly agree with the forecast. Cold front moves through central Europe in late thursday/friday. Moisture pooling allows for high CAPE, while deep-layer shear seems to be in the 20 m/s range while CAPE is very local, up to 2500 J/kg. There is no severe veering wind profile, so the SREH3 seems to be limited, but the best areas seems to be in the FVG, CTRL-Slovenia and SE-Slovenia/N-Croatia where the wind is best. So supercells are very much possible and given the low PWAT values we could see some nice classic ones. Main dangers will be large hail and strong winds. I can't give an exact target area because the area of possible activity will be rather large, and initiation is possible anywhere. There is a rather strong convergence along the Dinaric mountain range, but it will be mostly capped, except for the NW part. All-in-all, a pretty favourable setup for storm-chasing but a very dangerous situation for general public, we could see some major damage.

Happy hunting!

Follow up on the June 6th setup

For initial analysis view the previous post. Potential for the June 7th has vanished due to weak 0-6km shear. June 6th looks solid, the 500mb jet is going to be stronger than expected at first.

We are dealing with 35-45 kt 500mb jet through northern Croatia, Slovenia and NE-Italy, around 30kt @ 700mb, 20kt @ 850mb and around 10kt @ 925mb and 10m. Limiting factor is the unidirectional shear, which limits helicity, so supercells are possible, but not very likely. Storms will tend to get linear. Focus will be on the southern flanks of the lines for possible tail-end charlies. CAPE will range from 500 to 2000 J/kg according to WRF and GFS, locally maybe even more. Areas with high CAPE are forecast in CNTR-Italy, E-Slovenia and N-Croatia. No significant convergence lines other than above the Dinaric mountain range and the Alps are forecast, but the CINH will be rather small and with some daytime heating we should have no problem seeing breaking the cap. Similar conditions exist for E-Austria and W-Hungary.

Severe storms potential on Friday in FVG, Italy

Severe weather is expected on Friday afternoon in Italy, Austria, Slovenia and Hungary as the trough advances eastward. The trough will provide a 15-20 m/s 500mb jet and adequate lift on the front which comes in the late afternoon in N-Italy, N-Slovenia and W-Hungary. Models still do not agree with each other on how much CAPE will be available although they are starting to converge. GFS forecasts >1000 J/kg in NE-Slovenia, >1500 J/kg in N-Croatia and only a couple of hundred in central Italy with marginal CAPE in Friuli-Venezia region. ECMWF and GFS are drawing more CAPE in FVG region and less in NE-Slovenia.
The wind profile is great in the FVG region and a lot worse elsewhere. Medium SRH3 and nice veering suggest for potentially tornadic supercells. That will be basically the only interesting region. Other locations have more or less uni-directional shear so linear storms will probably be the primary mode. Still, large hail is definitely a danger, including severe wind gusts, but to a lesser extent, given the high moisture and PWAT values. High PWAT values also suggest HP supercells in the FVG region. With some low-level shear, tornado is not ruled out.

My biggest concern is the capped atmosphere in the FVG region. Elsewhere the cap will be broken rather easily. I remain somewhat sceptical for Italy. There is a strong convergence west of Venezia and Bologna, but the lack of serious lift in FVG region, the initiation prior to the front is questionable. Once the front comes, there will be no problem with initiation, but this will probably be rather late. I think the CIN will be in the 30-60J range and with the lack of serious convergence zones the initiation can be late.

The severe weather potential in NE-Slovenia and elsewhere along the front will be limited due to lack of low-level shear and these locations are probably not the best chasing targets.