The thunderstorms will be forced by a few different synoptic forcings today. First off, positive vorticity advection will aid in thunderstorm development, especially across parts of Texas and into Oklahoma, as a deep trough moves into those areas.



Additionally, 850 mb warm air advection will be occurring over many parts of the Plains and into the Mississippi Valley. This will especially aid the storms in the northern part of the area the Storm Prediction Center has highlighted as seeing the best risk for severe storms today (shown below).

Based on what I am seeing from the models however, I would say the main threats from this system will be damaging winds and large hail. Helicity values for tonight are shown below when they look the most impressive for the largest area and as you can see, they are still not that impressive for most areas.
Coupling this with shear (not shown), the best threat for any tornadoes tonight does appear to be from west central Kansas south into central Texas. In my opinion though, the best threat from this appears to be in south central Kansas and parts of central Texas very late tonight into early tomorrow morning. I do not expect there to be a ton of tornado reports with this but there should definitely be a few. Storms will additionally suffer from a lack of strong winds aloft, with only a weak cut off jet stream being somewhat apparent, mainly over the northern portions of the greatest tornado threat area.
Looking further towards tomorrow and Wednesday, this front will continue toward the east and the magnitude of severe weather that could accompany it is something the models have been flip flopping on now for days. Below is the threat for Day 2 from the Storm Prediction Center which would be tomorrow’s threat.
Tomorrow’s storms will suffer from some of the same concerns as today’s storms. Once again, no strong upper-level winds will be present which will decrease shear considerably. That being said, there will be some stronger winds at 500 mb but there will be no low-level jet at 850 mb. The problem with this system seems to be that not every parameter is really lining up at the same time, creating for just marginal severe weather threats instead of a more widespread and more intense threat. Warm air advection will once again help out many areas tomorrow but the positive vorticity advection will have pretty much vanished as the low becomes more cut off. I believe the main concern here is if storms can initialize tomorrow, they will have a lot of warm and unstable air to work with. Below are the modeled dew point temperatures for tomorrow afternoon, with widespread 60 degree Fahrenheit plus dew points across much of the eastern Plains, Midwest, and southeast.
Of particular note is a bubble of 65 degree Fahrenheit dew points mainly over parts of Kentucky and of course dew points of this value or greater across many areas of the Gulf states. Below is the modeled lifted index values for this same time period. Strong lifted index values are modeled for many areas along the Gulf coast but also in this same area of Kentucky.
If initiation can occur, some of the strongest storms may actually occur in this area which is currently not flagged as being at a slight risk for severe storms most likely due to these initiation concerns. Taking a look at where the storms fire up from this system will be the best indicator of where the severe weather will be heading for that day as attested by today’s line of storms which has now recorded hail and damaging wind reports across parts of eastern Texas, Louisiana, southern Arkansas, and southern Mississippi.
The Day 3 Convective Outlook from the Storm Prediction Center is shown below. You will notice no areas are currently forecasted in the slight risk category and this once again goes back to the initiation issues.
The events of today and tomorrow will likely tell a lot about how Wednesday’s severe threat may unfold. At this time, it appears the forcings are not too great, with limited warm air advection and shear. However, there is a lot of time between now and Wednesday and things may progress differently than the models are thinking right now. Models do indicate however that there may be a jet streak which forms over portions of the Gulf Coast threat area which may help aid in storm development. Certainly keep an eye on these next few days as this system crosses the country.