Outlook DAY 1 (valid: 01/05/2019)
An upper ridge over the Arctic region moves into Greenland while a deep trough moves from Arctic Russia into the N Europe. A shallow trough over the E Europe, with an embedded deep cold core low over Ukraine, continues east across the Balkan peninsula. The frontal system associated with the upper low brings significant severe weather into E Ukraine and SW Russia.
MDT risk has been issued for ENE Ukraine into SW Russia with threat for severe storms, capable of producing severe winds, large hail, tornadoes and torrential rainfall. A rather impressive setup is shaping up across the risk area given the strongly sheared and unstable airmass across the warm sector. An impressive LL shear / helicity is present south and along the warm front, favorable for tornadic supercells and possibly a tornado or two, even strong one! Large hail and torrential rainfall with flash floods will be accompanied by these storms.
ENH / SLGT risks have been issued for E/N Ukraine into SW Russia and N Georgia with more isolated threat for severe storms, capable of producing large hail, severe winds and torrential rainfall. The tornado threat is also a concern across the northern parts of the risk areas where best LL helicity overlaps with moderately strong instability.
SLGT risk has been issued for N Morrocco into NW Algeria with threat for severe storms, capable of producing severe winds, large hail and torrential rainfall.
MRGL risks have been issued for ESE Spain, NW and E Turkey with isolated threat for severe storms, capable of producing severe winds, marginal hail and heavy rainfall. Strongest cells in Spain could bring accumulated hail as storms will be quite slow moving.
TSTM risk areas have been placed where convective storms are likely to occur but should remain sub-severe.