Storm Forecast
Valid: Mon 27 Jun 2022 06:00 to Tue 28 Jun 2022 06:00 UTC
Issued: Sun 26 Jun 2022 21:40
Forecaster: PUCIK/GROENEMEIJER/GATZEN
A level 3 was issued for S Germany and NW Austria mainly for very large hail and damaging wind gusts.
A level 2 was issued for E Switzerland, NW Austria and SW Bohemia mainly for large to very large hail, severe wind gusts and heavy rainfall.
A level 2 was issued for E Spain mainly for large to very large hail.
A level 1 was issued N Spain and S France mainly for large hail and heavy rainfall.
A level 1 was issued for Czechia and NE Germany mainly for excessive rainfall, severe wind gusts and large hail.
A level 1 was issued for Denmark and S Scandinavia for excessive rainfall.
A level 1 was issued for SE Norway and adjacent parts of Sweden for heavy rainfall and tornadoes.
SYNOPSIS
Mid-tropospheric synoptic-scale situation over Europe is divided into 4 main features: a deep trough over the Atlantic, a low over the Black Sea, a ridge over the central Mediterranean and a high over the Baltics/W Russia. Two short-wave troughs will be associated with the Atlantic trough. The first one will move fast across Iberia towards the Balearic Sea. The second one will move from NW France towards Denmark.
Closer to the surface, a front will stretch from Norway through Denmark into Germany, SE France and E Spain and is forecast to move E during the day. Ahead of the front, mixing ratios between 10 - 13 g/kg are forecast, overlapping with lapse rates reaching 6.5 - 7.5 K/km. This will suffice for non-zero CAPE along practically the whole frontal zone. Together with the low over the Black Sea, the front will be the main driver of the DMC activity throughout this forecast period over Europe.
DISCUSSION
... E Spain ...
A brief window of opportunity will exist for a very large hail producing supercell (or two) as a strong forcing overspreads the area. 0-6 km bulk shear over 25 m/s will be present, but the increasingly dry air at the mid to upper troposphere will hinder convective initiation.
... Switzerland to SW Czechia and W Austria ...
A classic situation with SW-ly flow across the Alpine range is forecast over the area. High MLCAPE is forecast, exceeding 2000 J/kg, that will overlap with 15 - 20 m/s of 0-3 and 0-6 km bulk shear. The shear will be the strongest just to the north of the Alps as the surface wind turns to northeasterly during the day. High resolution convection-allowing models are confident in several intense storms moving over the area. These storms will likely be supercells , but may transition into a bow-echo later. Very large hail and damaging wind gusts are forecast. The resultant convective system will move over northern Austria and Bohemia during the night with threat of excessive rainfall and isolated severe wind gusts.
... Northeastern Germany to Denmark ...
Moderate vertical wind shear, high LCLs and MLCAPE between 500 and 1000 J/kg is forecast ahead of an eastward moving cold front over E Germany, suggesting that there is a risk of severe wind gusts or large hail. Models indicate that most of the storms will form along the front and as they move N they will be undercut by the front, becoming elevated. This will limit the severe wind gust threat to some degree. Heavy rainfall may also occur, especially over Denmark, where models simulate the highest precipitation amounts.
... Southeastern Norway and adjacent parts of Sweden ...
Besides the heavy rainfall threat, models suggest that some surface based storms may develop in the afternoon in the strongly sheared warm sector. Forecast hodographs show 0-1 km bulk shear between 10 and 15 m/s, along with 0-1 km SRH up to 150 m2/s2 and low LCLs, pointing at a tornado risk. The highest tornado risk is forecast near and N of Oslo.
... Northern Turkey ...
Moist onshore flow combined with orographic lift will result in numerous waves of showers and thunderstorms that may result in local flooding.
... Caucasus and S Russia ...
Moderate shear combined with MLCAPE around 1000 J/kg will sustain some well-organised storms capable of large hail. Storms will cluster, which will increase the heavy rainfall threat towards the late afternoon and evening.
