April 19, 2023 Large Hail & Tornado Event

During the late afternoon hours of April 19, 2023, thunderstorms formed along a dryline in southwestern and central Oklahoma, and quickly reached severe levels. These supercell thunderstorms eventually produced large hail of 1 to 3 inches in diameter and at least 18 tornadoes in the area. One strong and damaging tornado killed at least 1 person in McClain County near the town of Cole, and there were at least 188 injuries state-wide. More tornadoes occurred near Tinker AFB, Etowah, Pink, Bethel Acres, and Shawnee.

Teams conducted storm damage surveys in and near Cole, the Shawnee-Bethel Acres area, the Etowah-Pink-Stella area, and near Lake Stanley Draper on April 20th. Additional surveys were done on April 21st. Based on their research, 18 tornadoes were documented for the event, and preliminary EF Scale ratings were assigned to these 18 tornadoes.

The HRRR, a convection-allowing model, did not begin showing convective initiation in our area until the mid-morning initialization runs. The 17Z (12 PM) run showed very concerning model soundings in the vicinity of the southern OKC metro. Then, with the 19Z run (shown below), the modeled radar reflectivity imagery was alarming as the conditional threat for severe weather became more probable. This weather event highlights how even in such a near-term time frame, high resolution models are not perfect. Interesting side notes:

• Not all storms were predicted by the model
• Storms initiated earlier (21-22Z vs 22-23Z) and impacted the OKC metro sooner
• Storm locations were not predicted perfectly: although it picked up on a strong supercell affecting the metro, the strongest supercell was modeled as farther north than where the actual tornadic activity occurred
• The model had difficulty in predicting the slow/erratic motions of the storms
• Model forecast soundings and hodographs seem to do a poor job of the relatively weak, chaotic mid-level flow (700mb to 500 mb layer) which attributed to the slow and chaotic motion of the storms
• Model soundings did suggest strong tornadic potential (slideshow below)

During the event, the Oklahoma Mesonet station in Shawnee recorded a significant pressure drop and increase in winds as the tornado passed. The surface pressure decreased from 967.3 mb (9:35 PM) to 962.7 mb (10:00 PM) - a pressure drop of almost 5 mb. Also at 10 PM, the Shawnee site measured west winds at 44.9 mph with gusts to 84.1 mph.

The NWS Norman office communicates with our core partners during a severe weather event to facilitate warning information distribution during a severe weather event. Our partners include emergency managers, the media, and trained spotters. Below are excerpts of Chat from April 19, 2023.

The Norman WFO publishes and frequently updates severe weather and tornado potential graphics, along with timing graphics, on our website (www.weather.gov/norman).

This event was well documented with photos of large hail, wall clouds, and tornadoes from April 19, 2023. The NWS Norman office would like to thank members of the public for submitting these to our office directly or sharing on social media. Reports, such as these, are instrumental as we conduct severe weather operations.

Six of the eighteen confirmed tornadoes were significant tornadoes (i.e., damage rating of EF-2 or higher). The strongest tornado of the event was the Dibble-Cole-Goldsby tornado with an estimated path length of 11 miles, width of 1200 yards, and peak winds of 150 to 155 mph. The second strongest was the Pink tornado with an estimated path length of 3.3 miles, width of 200 yards, and peak winds of 140 to 145 mph.

Below is a map showing the tornado tracks from April 19, 2023. Feel free to zoom in, click on the damage points to see details and photos.