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A Risk of Severe Weather Today in MO/AR, E KS and E OK

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We wrote a bit ago about the slow ramp up to storm season, and here we are with our first risk day of March in the region. Today’s risk is centered across the Eastern areas of our region, and features a lot of the classic hallmarks of a severe weather day in the Southern Plains.

13z SPC outlook. 3/6/17

The Short Version

A cold front will be diving south across the Southern Plains this afternoon and evening. This cold front should spark storms across KS this afternoon and OK into the evening as it enters the state. Meanwhile, a dryline will be sharpening up across OK and extreme S. KS. This dryline could touch off a couple of storms as well late in the afternoon — but the odds are just as likely it stays completely dry. We’re also somewhat worried about storms going up ahead of both of these features in MO/AR in what we call the warm sector.

The SPC has outlined an Enhanced risk for the potential of damaging winds in MO/AR, with the risk tapering off the further W and S you go.

Dewpoint map for about 4 pm this afternoon. 4km NAM. 3/6/17.

Some In-Depth Thoughts

This is a day that’s definitely going to see storms form along the cold front as it pushes south this afternoon and into tonight. There is not much to breakdown there. Shear is pretty unidirectional (aka there’s not much turning) so expect storms to form quickly into a line along the front. Damaging winds and perhaps some marginally severe hail will be the main threats with that activity.

The dryline is the more complicated will it or won’t it scenario. In the graphic above, you see the dryline is pretty diffuse, with the highest dewpoint air a couple of counties east of where the true dryline is entering into late afternoon. The other big thing I’m noticing is the winds on either side of the boundary are not exactly all that different. This won’t create much convergence into the afternoon.

Add to that the best forcing kind of missing the dryline to the north and a capping inversion being present, I’m not so sure if you can get a sustained storm along the dryline today.

The other thing I’d watch for are falling dewpoints along the dryline. SW winds tend to be a drying wind on the Southern Plains, which is what makes dryline days with winds west of due south a bit less favorable for severe storms.

Storm Timeline

Right now, by 6pm tonight, it is expected that the front will be lighting up across Kansas and there is an outside chance the dryline could see a storm or two form across Northern Oklahoma.

Simulated radar. 4km NAM. 3/6/17

That area of N OK and far S KS will see the best glancing blow from upper air forcing which could help get a cumulus tower along the dryline over the top in the late afternoon. I’d suspect you’ll see watches in Kansas and N/NE OK later today.

By 9pm, the line will be growing upscale in E KS. 4km NAM. 3/6/17.

The line will continue to grow upscale and back build to the SW through the evening. Also, as we talked about — the potential for pre-frontal storms in the warm sector is there in MO/AR (and briefly SE KS). The greatest chance of tornadoes will be with that activity today if it does happen.

As the night progresses, expect storms to build further down the front into OK. The front should fire in OK sometime 9-midnight. 4km NAM. 3/6/17.

As the front surges SE in the overnight hours, storms will build along the front. Any frontal storms will pose a damaging winds threat. Pre-frontal storms will also carry a tornado risk.

Fire Weather Is A Huge Worry

If you happen to live west of the dryline today, you absolutely want to avoid outdoor burning and any flames period today. Temperatures will soar into the upper 70s/lower 80s, RHs will drop to dangerously low levels, and very strong SW winds will be present.

All of that leads to an extremely critical fire weather risk today. This is the biggest/most serious risk for fire weather conditions possible.

Extremely critical fire weather today. 3/6/17.

Our Next Severe Weather Risk

Looking ahead, it looks like another risk of severe storms could move in by late week into next weekend. Model differences are (as usual) large at this time. But we’ll be watching this one as well after we get through today.

Potential is there for severe wx later this week.