*Blog written at 2:15pm CDT, 6/11/13*
An enhanced severe risk of severe weather is expected to take place today, 6/11/13, and tomorrow 6/12/13. The primary threat will be damaging straight-line winds, each day, but very large hail, flash flooding, and a few tornadoes are also possible. A shortwave trough will be rounding the crest of a developing mid-level ridge. By this evening, the trough axis will be located from southeastern MT to northeastern CO. A surface lee low will be advancing eastward tonight, across the central High Plains. Rich low level moisture, daytime heating and shortwave trough influence will destabilize the boundary layer, creating severe weather from south-central & southeast MT, northeast WY, much of SD and northern NE. The severe threat will continue into IA, southern MN, southern WI and northern IL into the evening hours. Again, the main threat will be straight-line winds, but very large hail and even tornadoes will be likely with any stronger, discreet supercells that form. The tornado threat will likely diminish into the evening hours, once an MCS (Mesoscale Convective System)/linear line/bow echo of storms develop. SPC has issued out a “MODERATE” risk of severe storms for both days. SPC’s Day 1 (6/11/13) severe wind outlook:
Thunderstorms will persist into the morning hours tomorrow, 6/12, for much of the High Plains and Midwest regions. Surface low will deepen before reaching the Ohio Valley, tomorrow afternoon. Few supercells will be likely by afternoon, but storms will quickly cluster together and from an MCS that will produce damaging straight-line winds and large hail. This MCS will likely trek eastward through northern/central IL, southern MI, northern/central IN, northern/central OH and much of the northeast states by Thursday morning. There is a strong possibility that a derecho, or a very large and destructive bow echo, may form. In addition to the wind/hail threat, heavy rainfall is expected. Flash flooding will also be a huge problem! SPC’s Day 2 (6/12/13) Severe Probability Outlook:
The severe threat will continue into Thursday afternoon and evening for a good portion of the east coast.