Severe Wx Outlook Update: Wednesday April 19th

Wednesday’s setup brings the risk of severe weather to both of our coverage areas – Lower Great Lakes and Oklahoma.

Lower Great Lakes Discussion

Setup for Wednesday is complex but an overall low end setup that could pop a couple surprises for those not paying attention. The morning should start mostly to partly cloudy with some isolated activity around. Some clearing into the afternoon will allow for some heating. Warm front looks to get better defined by mid afternoon and line up just north of the I-80 corridor.  Winds north of the front will be out of the NW and south of the front they will comes from the SW. A nose of higher moisture, dewpoints into the low 60s, will move up through IN into NE OH and extreme SE MI. There should also be an area of higher instability from IL into northern IN, NW OH, and Southern MI with CAPE values at or above 1200 j/kg (bad drawing incoming below).  While this is meager for a typical severe weather setup, it might be enough to get a few severe storms going.

Wildcard to make this area interesting will be along the warm front. There could be a storm or two that will get into an environment where winds will back slightly and have an area of enhanced directional shear. Most like area for this to happen would be closer to Lake Erie as it appears now, but anytime you get storms that interact with a warm front there is a chance for a little added spin. What this could result in is a bit strong storm that could put down some 1″ hail or even a quick spin up. Still would classify this as a Very Low Risk  chance, but it is not zero in respect to the tornado threat. Marginal damaging wind (58 mph or higher) or hail (over 1″) at this point would classify as Low Risk.

Further west into Illinois and Southern Wisconsin, could see a severe squall line move through late into the evening with damaging wind and hail. There will also be an environment that could support severe storms earlier in the afternoon, but right now appears the chance of convection firing is low due to capping. Will pull this area back to a Low Risk.


This more or less will be a Thursday event as it may not impact Oklahoma Wednesday evening until Midnight rolls around.  Main threat appears to be some hail reports early transitioning to a wind damage through as we could see a bow echo develop over Northern OK. Threat area of a Low Risk. is going to run north of a line from Alva to Perry to Okmulgee to Fort Smith.

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