Storm Forecast
Valid: Wed 19 Jun 2024 06:00 to Thu 20 Jun 2024 06:00 UTC
Issued: Tue 18 Jun 2024 23:17
Forecaster: PUCIK
A level 3 was issued across E Lithuania, E Latvia, N Belarus and extreme W Russia mainly for damaging wind gusts, tornadoes, some of which may be strong, and large hail.
A level 2 was issued across Lithuania, Belarus, Latvia, SE Estonia and W Russia mainly for damaging wind gusts, tornadoes and large hail.
A level 2 was issued across N Czechia and Poland mainly for large to very large hail and severe wind gusts.
A level 2 was issued across central France, Switzerland and S Germany mainly for large to very large hail and severe wind gusts.
A level 1 was issued across Austria, SE Germany and S Czechia mainly for large to very large hail and severe wind gusts.
A level 1 was issued across NE Spain, France and NW Italy mainly for large hail and severe wind gusts.
A level 1 was issued across SW Turkey mainly for severe wind gusts.
A level 1 was issued across Caucasus area mainly for large hail and severe wind gusts.
DISCUSSION
... NE Poland through Lithuania, Latvia, S Estonia, N Belarus into W Russia ...
A severe weather outbreak is expected over the area, including possibility of several strong tornadoes and/or swaths of extremely severe wind gusts. This is a dangerous situation!
On the forward flank of a fast moving short-wave trough, a cyclogenesis is forecast on the frontal wave with surface pressure dropping below 1000 hPa. In response, lower tropospheric wind field will strengthen considerably, resulting in windspeeds up to 25 m/s at 850 hPa. A belt of moist airmass will be advected from Poland and combined with modest mid-tropospheric lapse rates, MLCAPE between 500 and 1500 J/kg is expected. Impressive long and curved hodographs are forecast by all models with 0-6 km bulk shear exceeding 25 m/s, 0-1 km bulk shear up to 20 m/s and 0-500 m SRH values locally exceeding 200 m2/s2. Combined with the low LCLs, environment will be prone to strong tornadoes.
Storms are expected to move across the domain very fast with speeds of above 20 m/s. Primary convective mode is currently uncertain and may consist of a combination of linear segments (including bow echoes) and isolated supercells. The strongest forcing is forecast over and near the warm front, where the most curved hodographs are anticipated. In case that linear segments are dominant, expect numerous swaths of severe to extremely severe wind gusts. In case that isolated supercells dominate, (strong) tornadoes combined with severe wind gusts and isolated large hail will be the primary threats. The threat will begin very early into the forecast period and will peak between 9 and 15 UTC.
... N Czech Republic into Poland ...
A cold front is forecast to cross the area in the late afternoon and evening hours. Especially over Poland, the cold front will move rapidly and is likely to undercut the storms, resulting in upscale growth and perhaps shortened cell longevity, apart from right-moving supercells that may stay ahead of front for longer time. A mix of splitting supercells and linear segments is forecast given strong, mostly unidirectional shear. The coverage of storms is expected to decrease towards central Czechia, where supercells will dominate as convective mode. Expect large hail and severe wind gusts with stronger storms. The likelihood of severe weather will increase towards E and S, where higher CAPE is simulated. Very large hail may occur with the stronger and longer-lived supercells.
... Austria to S Czechia ...
The coverage of storms is uncertain at the moment with models giving only weak CI signals and cold front not affecting the area too much. However, any storm that forms will become severe with threats of (very) large hail and severe wind gusts in the environment of 1500+ J/kg of MLCAPe and 0-6 km bulk shear exceeding 20 m/s.
... central France through Switzerland into S Germany ...
Multiple discrete supercells are forecast to initiate over France and/or NW Switzerland and move E/ENE in an environment of very strong deep layer shear (0-6 km bulk shear reaching over 30 m/s especially over France). This is supported by a numerous tracks of high updraft helicity values simulated by convection allowing models. Initiation will be secured by orography and/or by a diffuse frontal boundary that curves from central France through S Germany. CAPE will increase from W to E with the highest CAPE values simulated over the N flank of the Alps, where MLCAPE will exceed 2000 J/kg. While the coverage of the storms will likely be lower here compared to France, the threat of very large hail will be the highest. Storms will spread from France to Switzerland to S Germany. The storms may persist into late evening hours.
... N Spain into S France ...
Isolated supercells capable of large hail and severe winds gusts are forecast in an environment of modest CAPE and intense deep-layer shear.
... SW Turkey ...
Isolated severe wind gusts are expected with disorganised storms forming over a very deep and dry boundary layer with characteristic Inverted-V profiles in the prognostic soundings.
... Caucasus ...
Abundant CAPE above -10 deg C isotherm will combine with deep layer shear up to 15 m/s. Isolated well-organised storms, including marginal supercells, are forecast with the main threat of large hail, followed by severe wind gusts. Severe wind gust threat will be most pronounced over elevated area of the southern flank of Lvl 1, where deep boundary layers are forecast.
