Posted on April 25, 2016 at 4:41PM CDT
A moderate risk of severe weather is present across much of the central and southern great plains tomorrow for what could be a busy day. Despite being less than 24 hours away from the event, much remains unclear about timing, space, and storm evolution tomorrow. There's a lot that could make or break a high impact event but nonetheless the potential is there for dangerous storms capable of all modes of severe weather.
In the derived RAP 500mb analysis above we can see a large scale trough digging into the desert southwest late this afternoon. This will be our severe weather maker tomorrow.
The setup tomorrow will feature a dryline mixing into western Oklahoma by afternoon with an increasingly buoyant air mass ahead of it. Strong vertical and deep layer shear will overspread the warm sector as negatively tilted trough ejects through the area. There will be two areas of concern tomorrow. 1.) The triple point/warm front over north Kansas and southern Nebraska and 2.) the dryline across west Kansas and Oklahoma. The north option seems like the most obvious with favorable shear vectors and enhanced vorticity along the warm front but IMO east of north storm motions and messy convective modes will deter me from playing that area. There will likely be tornadic activity in this area but it will be short lived before storms get messy or cross boundary into cooler air mass. Farther south the low level wind fields aren't quite as impressive and a slight veer back veer component in the mid levels could lead to ventilating issues in the updraft and could lead to messy/high precipitation storm modes. Even so the large amount of cape that will be present could offset this and there will be plentiful deep boundary layer moisture to work with. My thinking is storms will initiate along dryline by late afternoon(earlier storm initiation is not out of the question either which could further complicate things) just west of I-35 and these will initially be supercells capable of very large damaging hail and tornadic activity. As the evening progresses storms may congeal into several clusters/line segments with a somewhat lesser tornado threat but continued hail/enhanced wind threat as they push into eastern and southeastern Oklahoma. There are a lot of variables that could make or break tomorrow and it's not even certain just how far east the dryline will mix which will play a huge role in where storms form. I don't think the cap is going to be an issue this time around as height falls overspread the dryline and forcing for ascent increases with the approach of the upper low. Convective temperatures should be reached with strong surface heating through the afternoon.
This forecast sounding per the 18z 4KM NAM highlights the VBV(veer back veer) component in the mid levels. Not a significant amount of veering, but could be enough to complicate things. This is the reason for the lack of more appreciable 0-1km SRH which explains the meager looking hodograph and lower tornado parameters. If a storm can turn right, low level SRH would be enhanced dramatically and thus the tornado potential would increase. I don't think there will be an outbreak of tornadoes, but there could be several intense supercells capable of very large hail and a couple of tornadoes. The potential for long tracked and/or strong tornadoes is there, it's just dependant on the variables discussed above. Unfortunately we won't know a whole lot more until tomorrow morning when we can watch real time surface obs/trends.
Above shows one potential scenario per the NSSL- WRF which initiates supercells near and just west of I-35. These would pose substantial threat to life and property if they form. It's important to note however that this model performed rather poorly in yesterday's event where the cap largely prevented storms across northern OK/S KS. We will see how it fairs tomorrow.
Bottom line is that you need to be prepared now for the possibility of all facets of severe weather tomorrow afternoon and evening. Have a plan and know what to do when warnings are issued. There are a lot of fancy graphics out there showing different things and it's easy to get confused so don't fixate too much on colors and lines and be prepared just in case. Will be out and about tomorrow so follow me on my social media pages for updates. Stay safe everyone!