VALID FOR 19-05-2014
The dominant feature on Monday will be a transforming upper trough across E Atlantic / W Europe, it is expected to transform into a deep upper low until Monday night. Strong WAA will be advecting unstable airmass northwards across Iberia and France. A short-wave trough moves across N Africa towards east. Further east, an extensive ridge lies over NW Russia where a stalled frontal boundary serves as a focus for another round of explosive severe storms across ENE Europe and E Scandinavia.
A MDT risk has been issued for northern Belarus, Baltic States, extreme NW Russia and extreme S Finland with threat for large to very large hail, severe winds, torrential rain and tornadoes. Storms should take place in the early afternoon and rapidly organize into severe storms given the moderate shear and strong instability in place. Storms may cluster into one or two larger system later in the evening when activity spreading towards S Finland.
A SLGT risk has been issued for areas surrounding the MDT risk across NE Europe / NW Russia and extended further SE along the frontal boundary across E Ukraine into SW Russia. Here, more isolated but still organized severe storms are expected. Supercells with large hail, strong to severe winds and some tornado threat are well possible.
A SLGT risk has been issued for N Iberia, across W France into the UK with threat for heavy rain, severe winds, marginally large hail and tornadoes. Parts of France (SLGT+ area) will be monitored for possible upgrade into a MDT risk on DAY 1 given the more favorable conditions for widespread severe storms.
A SLGT+ risk has been issued for NE Algeria into N Tunisia with threat for very large hail, severe winds and torrential rain with flash floods threat. Isolated supercells are likely in moderate sheared and strongly sheared environment by mid afternoon onwards. Area will be monitored for possible upgrade to MDT risk on DAY 1 given the possibility for more widespread severe storms coverage.
In between, lightning areas were placed where diurnal driver storms are likely in weakly capped unstable but weakly sheared environment. Some marginal hail or heavy rain threat exists.