A severe weather event is expected across the Southern Plains of the United States on Tuesday. The highest risk for tornadoes – including a few strong tornadoes – will be across Kansas and Oklahoma. At this time the highest tornado threat looks to remain just north of the Red River. The Storm Prediction Center has issued a category 4 (moderate) risk of severe weather for Central and Southern Oklahoma. That moderate risk line extends south to the Red River. For simplicity sake we’ll say it runs north of Highway 82 from Wichita Falls east to Sherman. A category 3 (enhanced) risk of severe weather includes all of Texoma, North Texas, and portions of Central Texas. A category 2 (elevated) risk of severe weather includes the eastern Big Country, Hill Country, South Texas, Brazos Valley, Northeast Texas, and portions of East Texas.

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I know everyone wants to look at a graphic to see their location relative to the highest risk zones. Understand that the difference between the enhanced risk and moderate risk isn’t that significant. Storms don’t read maps and certainly don’t care where we draw our fancy lines and colors. The point of this message is to advise you that severe weather is likely tomorrow evening. The most significant hazard tomorrow is expected to be very large to giant hail. The atmosphere will be extremely unstable and with strong wind shear in place storms will be able to keep hail stones lofted for a long time. The longer a hail stone is in an updraft the larger it becomes. The strongest storms will easily be able to produce hail larger than the size of baseballs tomorrow. Some hail sizes could approach the size of a softball in the strongest storms. Not all storms will produce giant hail nor will everyone in the severe weather risk zones be impacted by severe storms.

We could see two rounds of severe weather on Tuesday. The first round would be possible after 3 PM just east of a dryline. Current data suggests the dryline will set up within 25-40 miles of Highway 281 in Northwest Texas and western North Texas. A strong cap will help limit overall storm coverage tomorrow afternoon and we may not see development occur in Central Texas and the Hill Country until later tomorrow evening in round two. Storms that fire up tomorrow afternoon will rapidly become severe and supercellular. The strongest storms will likely produce hail larger than the size of baseballs and localized damaging wind gusts over 70 MPH. A couple tornadoes will be possible but the tornado threat should be highest north of the Red River. Could that change? Yes. Does it really matter when making this forecast and preparations to be prepared for severe weather tomorrow? No. Plan on there being nasty severe storms. A second round of storms will likely fire up after 7-8 PM as upper level forcing increases and the cap is rapidly eroded. These storms would likely fire up just east of the dryline as it ‘unzips’ from north to south. Those storms will also likely be severe but will hopefully form into a squall line pretty quickly. That squall line could develop into South Texas by Tuesday night. The line itself will move east with a threat of widespread damaging winds of 55 to 80 MPH. Large hail would also remain possible but likely not to the extent of discrete storms tomorrow afternoon. Brief tornadoes could also occur but again the threat would be lower than what we would see with discrete storms.

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Have multiple ways of receiving severe weather information tomorrow. The National Weather Service and preferred local media are two great sources. We’ll be out chasing and may not be able to post frequent severe weather updates. I do plan on posting a small update after 10 PM this evening with any changes weather model data shows along with a general summary. I realize folks are probably scared but realize this is not a unique or historic threat. I don’t expect a tornado outbreak in Texas tomorrow nor do I expect there to be a high number of strong/long-track tornadoes in the state. Understand that it only takes one tornado coming down your street to make it an ‘outbreak’ or historic. That’s why you should take all severe weather seriously and enact your severe weather safety plan. Don’t have a plan? No problem! Take the time now to form one. Information on severe weather safety plans can be found here.