May 22, 2019

Strong, Long-Track Tornadoes Possible in Okla., Kansas, and Missouri on Wednesday



Talk about things ramping up in a hurry. Conditions have quickly grown favorable across the southern and central Plains for severe thunderstorms capable of producing strong, long-track tornadoes. The quick ramp-up and lingering feelings from Monday's severe weather threat means that today's threat for severe weather could catch people off guard.

GREarth/AllisonHouse


At 3:30 PM CDT, the Storm Prediction Center had issued two PDS Tornado Watches covering a vast swath of the central United States from southern Oklahoma to central Missouri. The watches include Wichita Falls, Oklahoma City, Tulsa, and Joplin. "PDS" stands for "Particularly Dangerous Situation," enhanced wording added to a tornado watch when conditions are favorable for the development of strong, long-track tornadoes.

The environment seems primed for the development of supercell thunderstorms capable of producing strong, long-track tornadoes, as well as damaging wind gusts in excess of 70 MPH and hailstones the size of baseballs or larger. There may not be a large number of storms, but the storms that do form could get ugly in a hurry.




There's a moderate risk for severe weather beginning in northeastern Oklahoma and stretching through central Missouri, including the Tulsa metro area, Joplin, and stopping just short of Columbia and Jefferson City, Mo. A heightened tornado threat exists from the PDS Watch in Oklahoma through central Missouri. The black hatching on the tornado probability map above shows where the conditions are most favorable for thunderstorms to produce strong, long-track tornadoes.

Much of the severe weather expected this evening may occur after nightfall, which, combined with heavy rain, may make tornadoes impossible to see before they're on top of you. Don't wait to see a tornado before you take action if you're put under a tornado warning.


The parameters in place aren't as intense as they were on Monday—where we could have seen a very ugly situation had thunderstorms been able to develop—but that was an extreme risk, and the high-end is the high-end for a reason. Monday's risk saw all the ingredients, but few thunderstorms formed to tap into that highly favorable environment.

Today, however, thunderstorms are developing along the Red River (the Texas/Okla. border) with more on the way. Thunderstorms that develop will soon move into a position where they can tap into those favorable ingredients and begin rotating.

Pay close attention to severe weather warnings today and stay close to safe shelter if you have to take quick action. Don't let a false sense of security set in because we got lucky on Monday. The SPC doesn't include PDS wording in watches lightly.

Here's a pure and shameless copy/paste of the safety advice I included in my post on Monday morning. Folks in this part of the country are always prepared for severe weather in late May, but it's important to make sure you're ready to go if you're under a warning.

Plan your day accordingly. Don't run to Walmart or another big box store when storms are on the way. Mentally map out your home, work, or school to scout out the safest place to go if a tornado warning is issued. Do you have a safe building to pull off the road if you have to go out? If you have to be in a big box store, do you know the safest place within the store? Ask the manager. Seriously. They have to have a plan for that kind of stuff in this part of the country.

Leave mobile/prefabricated homes. Spend the whole day somewhere safer—a friend's house, the library, anywhere but home. Mobile homes can start to roll and break apart in winds as low at 70 MPH. Even a small tornado can heavily damage or destroy a mobile or prefabricated home and leave you in a life-threatening situation. Hell, the bathroom in a McDonald's provides you with more protection than a mobile or prefab home.

Consider the flooding risk when seeking shelter from a tornado. If your home is in a flood-prone area, consider leaving and going somewhere safer for the day. You don't want to be put in the impossible situation of deciding whether to go to the basement—and possibly drown—or stay at ground level and possibly risk a direct strike from a tornado.

Wear a helmet, jeans, and closed-toe shoes if you have to take cover from a tornado. The most vulnerable part of your body in a tornado is your head and a helmet will spare you from at least some debris if the worst happens. Jeans and closed-toe shoes will protect your feet and legs if you have to walk over debris.

Make sure wireless emergency alerts are activated on your cell phone. These alerts have saved countless lives over the past couple of years. Some folks disabled these alerts ahead of a nationwide test last year. Keep them on! I often receive my emergency alert within a minute of my weather radio going off.

Use a weather radio. Many people in this part of the country already have weather radios. Modern weather radios are like smoke detectors for the weather. You can program them with your county's unique code so they sound a loud siren when you're placed under a watch or a warning. Most devices even flip on the weather radio feed and read the warning out loud.

Don't rely on tornado sirens for warnings. These systems are outdoor warning systems and they are not meant to be heard indoors. Tornado sirens are also vulnerable to technical failures, power outages, and wind shifts that affect where they can be heard.

Don't hide from a tornado under a bridge or overpass. It is not safe. Strong winds grow even stronger when they press under a bridge. Three people died under three separate bridges during the 1999 Bridge Creek-Moore tornado in central Oklahoma. Bridges will not protect you. Get to a sturdy building and take shelter there.

Don't hide from large hail under an overpass, either. Drivers trying to protect their vehicles from hail damage often wind up creating a traffic jam, stranding hundreds (possibly thousands) of people and emergency crews behind them. This is especially dangerous since large hail often precedes a tornado in a classic supercell, which could leave all those people trapped in the path of a tornado with nowhere to go.

Don't go storm chasing. Wednesday's storms are expected to form in a bad part of the country for storm chasing. Trees, hills, and a limited road network will combine with ongoing widespread flooding to make keeping up with, and staying ahead of, dangerous thunderstorms a risky gamble. Leave chasing to the experts...and, based on what we've seen lately, even some of them shouldn't be out there.

Keep up with the Storm Prediction Center's website through the day. The SPC issues severe thunderstorm and tornado watches, as well as short-term forecast discussions that can give you a heads-up of what's coming over the next couple of hours. Stay proactive on a day like this. You should know about the threat for storms an hour or two before they arrive. Don't simply wait for a warning to act.

(Post updated at 4:35 PM EDT to include the new PDS watch stretching through central Missouri.)


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I graduated from the University of South Alabama in 2014 with a degree in political science and a minor in meteorology. I ran Gawker's The Vane for two years and I've contributed to Mental Floss, Forbes, Popular Science, and the Washington Post's Capital Weather Gang. I also teamed up with Outdoor Life to write a book called The Extreme Weather Survival Manual, which came out in October 2015.

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