Ever since earlier this week we've had our eye on today's setup in Central Kansas. The moisture return, a low developing over Southwest Kansas, and upper-level wind support all kept us coming back to look at the models to see how it was shaping up. For a while it looked like the cap, or a layer of instability-inhibiting warm air aloft, was going to surpress storm formation but now we're seeing a situation where there will be just enough break in the cap to allow for a few isolated supercell storms to form. To get surface heating today to break that cap we need to clear out the clouds across Kansas first. A push of dry air at around 10,000 feet is currently moving from Southwest Kansas to the northeast and is eating these clouds for breakfast as you see in the satellite image to the right. We expect this to keep moving throughout the day and hopefully it will clear out the clouds in time to get some serious surface heating going.
The big story here today is the moisture return. For the first time this week we are seeing a situation where dew points will surge into the mid to upper 60's. Yes! This much-needed moisture will be the fuel for storms this afternoon and should give us a much better show than the moisture-deprived low-precipitation storms we've been seeing lately. While we don't have this moisture in the area quite yet, it's streaming in like crazy right now. Strong easterly and southeasterly winds are blowing this moisture into Kansas from Missouri and Oklahoma and will continue doing so throughout the day. Having mostly easterly winds in Kansas right now is a very good thing because this is creating just about optimal low-level shear for rotating supercell storms.
Speaking of wind shear, this will create quite a bit of helicity, or a corkscrew-like rotation of air in the atmosphere. When you combine helicity with instability in an equation you get the Energy Helicity Index (EHI). As I've said before I think that indicies and parameters can be distracting since human analysis is always better than a formula, but EHI seems to be fairly reliable since it is so basic and relies on two very basic ingredients. This afternoon's EHI values in Kansas will be the highest we've seen out here this season according to the Rapid Refresh model. That's some great news for storm chasers because higher EHI values typically correlate with enhanced tornado potential.
The Storm Prediction Center has a Slight Risk for severe storms today from Iowa to the Texas Panhandle and within that a 5% tornado risk in Kansas. This is quite the change from the previously non-severe "general thunderstorm" outlooks that they had been issuing for today because of the concern that strong capping may inhibit storm development. Today is our last chase day out here for Tour 3 and my last day out here until I come back for a week in June. If we could see some good storms today that'd be a great end to the first part of my trip! Tonight once we're finished chasing we'll be traveling back to Oklahoma City where I'll fly back to Louisville from tomorrow morning.
Follow up-to-the-minute reports on our chase on my Twitter and Facebook accounts!