Storm Forecast
Valid: Tue 16 Jun 2026 06:00 to Wed 17 Jun 2026 06:00 UTC
Issued: Mon 15 Jun 2026 11:49
Forecaster: TUSCHY
A level 1 was issued across parts of CNTRL Germany mainly for some hail, gusts and heavy rain, but also for an isolated tornado risk.
A level 1 was issued for Sicily mainly for isolated large hail, heavy rain and strong to isolated severe gusts. An isolated tornado event is possible.
A level 1 was issued for parts of NW Russia mainly for some hail, gusts and heavy rain.
A level 1 was issued for N Tunisia mainly for isolated hail and heavy rain.
A level 1 was issued for parts of N Italy mainly for some hail and gusts.
A level 1 was issued for Montenegro to Kosovo mainly for some hail and gusts.
A level 1 was issued for parts of Bulgaria mainly for (isolated large) hail, gusts and heavy rain.
SYNOPSIS
An initial still progessive wave train of mid/upper waves turns quasi-stationary troughout that forecast period with a building ridge over SW/W into CNTRL Europe. This changing pattern is also seen in zonal wave flux activity, which starts to converge into the building anticyclone during the day. With high-latitude blocking present, two cut off cyclones are forecast, one over the Baltic States (building NE) with the other one lifting NE offshore of Ireland. The strengthening and northward building ridge axis is forecast to affect Spain/W-France and remains more progressive to the N (North Sea).
A sharp and eastbound translating low-amplitude wave affects S/CNTRL Italy with a rather active thunderstorm day especially for Sicily.
At the surface, there won't be too many fronts to talk about. The depression over NE Europe gets accompanied by an active/northward surging cold front and a westward shifting warm front, which affects Finland from E to W. The attendant warm sector shrinks as the occlusion process sets in.
Another weak surface imprint with warm/cold front is forecast beneath the building ridge over CNTRL Europe, as an upper short wave slides SE and gets accompanied by a weak/diffuse surface depression. This vortex dissolves during the forecast somewhere over N-CNTRL Germany and degrates into a SE-ward shifting open-wave.
DISCUSSION
... CNTRL Germany ...
Downstream of the building ridge axis, a de-amplifying low-amplitude wave crosses Germany SE-ward during the day with an imprint seen all the way down to the BL, where a diffuse vortex opens-up into an open wave. This wave is accompanied by dpCVA and ongoing WAA as TPWs up to 30 mm spread E in the open warm sector. This area is also covered by elongated integrated vapor transport vectors, so initiating convection will see good moisture supply from the W.
A confined area with best moisture advection beneath still cool mid-levels results in an area with 700-1500 J/kg MUCAPE over CNTRL Germany.
Shear supports organized convection, as DLS pushes towards 20 m/s with 0-3 km shear up to 15 m/s. Ongoing WAA also increases SRH with curved hodographs forecast.
CI remains more uncertain and is found upstream of an eastward shifting and stratiform-dominant rain shield (with embedded thunderstorms), which affects E/S Germany until noon. Dewpoints surge up to 6K and some mid-level drying from the W should add at least temporal diabatic heating behind the WAA rain. ID2 is on the reluctant side of the NWP spectrum with others offering scattered CI. It is not unknown that ID2 has some CI issues in diffuse forcing setups. With some uptick in LPI tracks in ID2-EPS and otherwise supportive conditions for iolated to scattered CI, confidence in a more active severe weather day increases. Weak CIN probably supports CI first along the orography with later storms also firing off the orography.
The mix of (semi) discrete CI within the broadening and strongly sheared warm sector points to numerous organized multicells and a few long-tracked supercells and even the reluctant ID2-EPS had a few decent UH tracks in latest runs. Missing gust swaths (even in EPS data) point to lingering CIN issues with deterministic runs showing weak capping at 900 hPa probably due to uncomplete BL recovery (2m temperature) behind the preceding WAA rain event.
Hence the main risk will be hail, although a deepening/warm subcloud layer should lower the final hail size mainly to a 2-4 cm range next to locally heavy rain (mainly during initiation and cell merging) and strong gusts. The final tornado risk is influenced by mentioned lingering capping issues, but at least on a regional scale there will be an augmented tornado risk due to some CAPE3 and lowered LCLs (e.g. ID05 over W-CNTRL into CNTRL Germany).
We stick with a broad level 1 for now with ongoing issues of thunderstorm coverage and a somewhat muted degree of severe with most of the mentioned hazards. However, nowcast trends need to be monitored closely as not much modification of the BL airmass is needed for a more robust severe risk.
A low-confidence trend in spotty CI over SW Germany was noted in NWP data and can not be ruled out completely. Slim signals in EPS data and a drier BL kept us from expanding the lightning area that far to the SW. Any cell would be accompanied by some hail and gusts.
... Sicily and adjacent areas ...
The estbound moving wave is captured nicely f.ex. in the latest IFS-ENS output, indicating somewhat augmented H5 geopotential height spread along its E fringe, so not much amplitude modification is forecast in following NWP updates. This more or less stable path forecast is helpful in adding confidence in a regionally augmented wind field along its southern fringe, which affects Sicily during that forecast.
CI is expected from noon onwards with the approaching wave from the W (slight cooling confined to mid-levels) and due to the diurnal driven onshore flow of the evolving sea breeze front, pushing a marine airmass ashore. CIN is weak but increases to noteworthy values with ECAPE correction. Still, scattered thunderstorms should evolve over N-Sicily drifting SE during the forecast.
Shear is modest, but up to 15 m/s (3 and 6 km bulk shear) on a temporal and regional scale (SE fringe of the approaching wave) will be enough for pulsating convection with a few multicells/transient supercells.
Some mid/upper level moisture advection from the African ITCC into that wave and the already present marine airmass push TPWs into the upper thirties, so instances of heavy rain with spotty flash flooding are possible next to isolated hail and strong (wet downburst driven) gusts. A low-end tornado risk exist mainly for any storm riding the inland shifting marine front with maximized BL moisture depth/CAPE3. A level 1 covers that risk.
Further N towards CNTRL Italy, moist onshore/upslope flow improves MUCAPE during the day into the 1000-2000 J/kg range with very weak shear. Avoid of any helpful background/synoptic-scale forcing, isolated CI is forecast with a spotty hail/rain and gust risk - not adequate for a level issuance.
For NE Tunisia, the passing wave adds some CI probabilities (probably ongoing from the previous night), before ridging builds in with a strengthening cap. High-based convection poses an isolated hail and heavy rain risk.
... Baltic States into Belarus ...
CAPE/shear remains on the lower-end side along the S fringe of the cyclonic vortex, with stronger updrafts capable of producing graupel an gusts. Would not be surprised about a few funnel/short-lived tornado reports with better hodograph signature/some SRH1 and at least noteworthy CAPE3. This is not enough for a level issuance.
... Far NE Europe into NW Russia ...
A closing warm sector features weak shear with MUCAPE up to 1000 J/kg, so scattered to widespread convection is forecast. Heavy rain, isolated hail (for initiating cells) and gusts are forecast. Early CI and messy mix of convection with convectively enhanced rain preclude a focused severe risk area and hence no level was added for most parts. This is not valid for areas N (including parts of the oblast Murmansk), where some diabatic heating increases MUCAPE into the 1500 J/kg range, raising confidence for a few severe reports.
Betimes, an occlusion/deformation band evolves along the W/SW fringe of the vortex with a more foused heavy rain threat, but again, uncertainty in convective coverage precludes a level 1 area. Some flooding problems could evolve with 40-80 l/qm/24h rainfall amounts seen in NWP guidance, extending W into SE Finland.
... N Italy, Montenegro to Kosovo and parts of Bulgaria ...
All these level 1 areas remain marginal events with confined swaths of better CAPE/shear overlap, assisting in multicells and an isolated/transient supercell event with hail, gusts and heavy rain.
