Doing a special write up for the severe threat over Oklahoma on Tuesday April 25th. Initial outlook put out yesterday had an Elevated Risk over Eastern OK. A refined map is part of this discussion with an outlined area. Now as something that is a bit different here, the outlook displaced is not the SPC forecast. A decision was made to try a more rational risk chart where the terms are more closely align to what they actually mean in English. Not knocking SPC by any means as it would not be unexpected to see the words drop all together and SPC put out a Risk Level number (which are already assigned to each category) instead in the not too distant future.
So big adjustment to this outlook is the inclusion of Central Oklahoma and less focus on all of Eastern OK. Portions of Eastern OK south of I-40 are still in the risk outlook, but overall the threat drops considerably. The main reason for the changes is the continued signalling of the activity firing northwest of the I-44 corridor from the OKC Metro up to just west of Bartlesville. Storms should get going pretty quickly starting around 5-6PM. There will be a very small window initially of a tornado or two, but overall that risk is low. The main threat will be wind as the storms evolve into a solid line/complex that moves through NE OK into AR and MO.
Overall setup is going to drive these storms to go linear pretty quickly, but there will be some backing to the winds at the start. SBCAPE values at or above 2500 j/kg seem probably over much of the risk area. Moisture will be in the place with dews into the mid 60s. LCLs will be pretty low so should have some lower bases with the storms as they start out and 1km helicity would provide for some initial favorable shear for a quick spin up or two. The best chance for that would probably be a tail-end charlie situation of a storm sitting at the end of the line that isn’t going to have any obstruction to its environment.
Not expected a significant day, but it only takes one storm to ruin someone’s day. Overall feel confident in the risk level and placement for Tuesday.