...S Netherlands, Belgium, Luxembourg, extreme W / SW Germany, extreme E France...
Some low-end instability will form near the centre of the upper low over the SW North Sea during the afternoon. This plume of unstable air will travel to the southeast with the left exit of a 45 m/s jet streak at 500 hPa, affecting most parts of the Benelux countries, W Germany and E France. Locally, 0-6 km deep layer shear reaches values around 40 - 45 m/s and EL temperatures are forecast around -30°C so that storms may profit from the intense vertical shear. Current thinking is that some convective lines will develop, posing a threat of severe wind gusts. It is likely that some storms within the line will contain mesocyclones. LLS will reach values of 10 - 13 m/s and in this environment with rich BL moisture, an isolated tornado may form. The severe wind gust / tornado threat should be maximised between 15 UTC and 00 UTC.
Some low-end instability will form near the centre of the upper low over the SW North Sea during the afternoon. This plume of unstable air will travel to the southeast with the left exit of a 45 m/s jet streak at 500 hPa, affecting most parts of the Benelux countries, W Germany and E France. Locally, 0-6 km deep layer shear reaches values around 40 - 45 m/s and EL temperatures are forecast around -30°C so that storms may profit from the intense vertical shear. Current thinking is that some convective lines will develop, posing a threat of severe wind gusts. It is likely that some storms within the line will contain mesocyclones. LLS will reach values of 10 - 13 m/s and in this environment with rich BL moisture, an isolated tornado may form. The severe wind gust / tornado threat should be maximised between 15 UTC and 00 UTC.
