Thursday, May 18, 2017 9:41 AM

Southern Plains Tornado Outbreak Possible Today

Christopher Nunley

Damaging thunderstorms and strong tornadoes are likely across parts of the Southern Plains later today into the overnight hours. The Storm Prediction Center (SPC) has a high risk of severe thunderstorms across northern Oklahoma and southern and central Kansas; a moderate risk for much of central Oklahoma and Kansas surrounding the high risk area; an enhanced risk from northwestern Texas through parts of Oklahoma and Missouri, which is surrounding the high and moderate risks; and a slight risk for much of northern Texas down into the Texas Hill Country.


Thunderstorm Outlook (SPC)

A high risk, which is rare, is a category 5 risk on a scale of 1-5 (with five being the most significant). By SPC definition, a category 5 risk means this area can expect widespread severe weather with several widespread long-lived damaging thunderstorms. This is a particularly high probability of strong tornadoes today for parts of Oklahoma and Kansas.

Severe Thunderstorm Risk Categories (SPC)

This afternoon, strong upper-level winds will move into western parts of the Southern Plains as a powerful upper-level low advances towards the region. Currently, deep and rich moisture has moved into northern Texas (dewpoints are >70 degrees); this moisture will continue to advance northward, setting the stage for a very unstable environment. This will lead to explosive thunderstorm development by the afternoon hours (after 3:00PM) in western Oklahoma and western Kansas once the dryline sharpens and creeps eastward. With the initial mode of thunderstorms expected to be discrete and supercellular, they will likely produce tornadoes due to the deep-layer shear and very conducive low-level shear.

Thunderstorms by the evening should begin to slowly merge to develop a complex, which would aid in an area of enhanced wind-damage potential. The best area to see damaging winds from this complex are across central and eastern Oklahoma as well as northern Texas (around 9:00PM). It should be noted that some of the short-range guidance is indicating thunderstorms may develop during the early afternoon hours across southwestern Oklahoma/northwestern Texas. This could throw a ‘fly’ into the forecast because it could act to lessen the severe threat for this area and possibly areas further north. I will keep a close eye on this scenario to see how it plays out.

Again, an outbreak of severe thunderstorms is possible for the Southern Plains this afternoon. All modes of severe weather are possible. This forecast is not intended to create hype or worry you. I am simply implying the severe threat is real today if all the parameters come together as the numerical guidance is indicating. Do not panic, just have a plan in place. Tune in to your local television station so you’re notified of warnings, call your elderly neighbors to make sure they have a plan, and know where you will shelter in case a warning is issued for you area.