Forecast for the week of October 26th + what was the El Reno tornado ?

By: Paige Klobucnik

Hi friends! I hope you all had a good week last week, temperatures were a bit high, but cool mornings made up for it, at least it did for me! This past Saturday I went to sick new world in fort worth and it was pretty sunny, unfortunately I got a little sunburn on my nose! But it was awesome. I got to see some of my favorite bands like System of a Down, Evanescence, Superheaven, Failure and more!!! Here's some cool pictures I took! 😎

It is finally the week of Halloween! I am sure you all are curious about what the weather will look like, whether you are trick or treating, or have other plans. Temperatures for this week are to remain around or slightly above normal, with highs in the low 80s and upper 70s, rain chances are looking to be increasing into the weekend, so be on the lookout for that, but I will do a Halloween specific forecast on Thursday, for a deeper dive on what the weather looks like when it gets closer. Forecasts get more accurate the closer we get, so I will be more sure of what the weather looks like then! I love Halloween, here's a fun little throwback of one of my childhood Halloweens!

Today I wanted to talk about the record breaking “El Reno Tornado”, which killed 8 people and was 2.6 miles wide, this is the widest tornado ever recorded! I do want to address one thing first, the size of a tornado actually does not determine its strength, El Reno was rated an EF3 tornado, whereas narrower tornadoes can reach EF4 or EF5 wind speeds! The reason why this storm grew to the size it did, and why it was so destructive, was because of the atmospheric conditions that allowed it to grow. 3 air masses actually came together to produce it, there was cold arctic air from Canada in the north/northwest, dry air from the west and southwest, and warm, moist, and unstable air from the Gulf of Mexico. The cold air advection via a cold front had become stationary, meaning that the warm/cool air meeting had nowhere to move horizontally, so the warm air overtook the denser cooler air and rose as the surface heated during the day time. 

Here you can see the stationary front created by the air masses colliding!

There is a variable we use called CAPE, which is convective available potential energy, and the values for this were exceeding 5000J/kg. CAPE is essentially the amount of fuel that is available to a developing thunderstorm, it describes the instability of the atmosphere and gives us an approximation of updraft strength within a thunderstorm. So the high CAPE value associated with El Reno, means that the atmosphere is extremely unstable and a strong updraft is produced. A value greater than 4000J/kg is considered extremely unstable so 5000J/kg is definitely a recipe for disaster!!! 

There is another variable called CIN, which is convective inhibition, or the amount of energy that prevents an air parcel from rising freely into the atmosphere. During El Reno, the CIN prevented the hot air at the surface to rise, and when this energy barrier was overcome, it resulted in this extremely warm air rising very quicking, producing convective thunderstorms. 

Here is a visible satellite image of these thunderstorms, the wrinkle like characteristic of the cloud tops indicate this rising air hitting the tropopause, creating overshooting cloud tops on these cumulonimbus clouds. As time progressed, these thunderstorms grew rapidly, because of this stationary front they were on, they were not traveling much, further fueling these storms and releasing a lot of rain.

Here is radar imagery of the maturing convective thunderstorms, and the supercell that produced the El Reno tornado.

You can see a hook-shaped precipitation on the southern end of the supercell, this is called the “hook echo” and is indicative of tornado activity. You can see the same hook visualized with a swirling green and red pattern in the same spot on the velocity radar on the right, the green colors mean that wind is blowing towards the radar, and the red means wind is flowing away from it. When red and green are so close to each other, it indicates there is rotating motion in the atmosphere.

Thankfully, the tornado dissipated prior to interacting with more populated areas, but many people were caught off guard. Extremely heavy rain shielded the tornado from view, making it hard for storm chasers and drivers to see. In the image below, you can see the 2.6 mile wide tornado, with only 0.3 miles in the center being the visible part of the tornado (the condensation funnel), this made people think they were safe from the winds that were up to 290 mph, when they weren't.

Thank you guys for reading! Tornado's are my favorite weather phenomena to dive into, and the El Reno tornado is extremely interesting to look at! I hope you all have a good week, and I will be back on Thursday for a Halloween forecast! :)