The Tornado Outbreak of May 19, 2013

On Sunday, May 19th, with an upper-level low approaching off the Colorado Front Range through the Panhandles, a fairly stout dry line began to surge eastward off the Texas Caprock and Panhandle reaching as far east as El Reno, OK. With deep layer moisture and favorable wind fields across central Oklahoma, supercell thunderstorms quickly developed along the dry line, primarily along the U.S. Interstate Highway 44 (I-44) corridor, and moved quickly to the east/northeast. A total of 7 tornadoes occurred that day in the Norman forecast area - all spawned from 2 supercell thunderstorms - and impacted Edmond, Arcadia, Luther and Carney, Norman, Lake Thunderbird, Shawnee, and near the town of Prague. The most intense tornado occurred just west of Shawnee, where EF-4 damage was found as the tornado traveled north of the city before crossing U.S. Interstate Highway 40 (I-40). Two people were killed and fourteen injured as a result of the tornadoes on this day. One man was killed in a mobile home park in Bethel Acres, and another in his vehicle in Little Axe.

The map (above) displays the damage paths with contours delineating the extent of EF-0 (light blue), EF-1 (green), EF-2 (yellow), EF-3 (orange), and EF-4 (red) damage from the survey.

The interactive map (below) walks you through the sequence of tornadoes that occurred on May 19, 2013. As you scroll, you will see a picture of the tornado (if available), along with details such as the duration, path length and path width.

In the days leading up to the event, the Norman WFO office prepared graphicasts and recorded severe weather briefings on YouTube for dissemination to the public. Here is a timeline of these graphics and briefings:

Twice a day, every day, NWS meteorologists release a weather balloon which has an attached radiosonde. On days such as this one, when severe weather is anticipated, a special sounding may be done to gauge the latest weather conditions. Once the balloon finishes its ascent and pops, the upper-air data is plotted on skew-T diagrams, which provide a snapshot of the thermodynamic profile of the atmosphere. On May 19th, a special weather balloon was released at 1pm to see whether the "cap" was nearing its breaking-point. Below are the skew-T charts from Norman, Oklahoma at 7am and 1pm. The afternoon sounding (right) shows that the cap close to eroding, indicating that the time for thunderstorm development was near.

The weather balloon data from multiple NWS forecast offices is then analyzed on a map at standard pressure levels above the ground. Here are the upper-air and surface analyses. The charts are presented from top-down (i.e., top of the troposphere down to the surface).

Other than the NWS Norman Webpage, Facebook and Twitter are a few of the main platforms used by the Norman WFO to communicate information to the public. Tweets from the May 19th event are provided below.

Before, during, and after a weather event, the Norman WFO office communicates with our core partners (i.e., emergency managers, broadcast media, etc.) in an online message forum called NWSChat. Communication excerpts from that day are shown here.

May 19th is often overlooked when compared to the other big events that May. Here are some photos and video from the severe weather that impacted our area on the 19th.

The tornado outbreak of May 19, 2013 resulted in at least 29 tornadoes nation-wide, as seen in the SPC Storm Reports Map (above). The storm reports within the NWS Norman's area of responsibility are shown in the preliminary storm report (below).

If this had been the only tornado event of the month, it would have been considered a very highly-impactful event. Out of the 29 nation-wide tornadoes, there were at least 8 confirmed tornadoes that affected Oklahoma that day. Three significant (greater than EF2 damage) tornadoes occurred within the Norman forecast area. The strongest tornado (EF4) was on the ground for 23 miles and affected east Norman to McLoud.

Meteorologists from the NWS Norman WFO conducted damage surveys following this event. During the survey, damage points were marked electronically during the damage surveys and tornado paths followed soon thereafter. Feel free to zoom in, and click on the damage points discovered during the survey.