Quad State Tornado

The Quad State Tornado hit the hometown of one of my students, Dallas McKinney, Friday night.  Dallas shares his perspectives on the event below.  We are all grateful that Dallas' family and friends are safe.  All opinions expressed are his own and not necessarily that of the University of Utah or his current or former scholarship/grant sponsors (NSF/NWS/NOAA/NASA).

Jim

Perspectives on the Quad State Tornado

Dallas McKinney
University of Utah

I wanted to give a brief discussion of the mile-wide (likely EF-5) tornado that hit my hometown of Mayfield, KY Friday night and let everyone know that my family and friends are alright. Although supercells are mesoscale phenomena and tornados are microscale phenomena, they require favorable synoptic environments to spur their development. Attached is the closest sounding from where the tornado formed (Little Rock, AR). Notice the sufficient ML CAPE (~2000), high surface dewpoints (~67), and especially the extreme low level shear. Winds of 100 kts at 300 mb likely mean a jet streak and/or PV wall is occurring over the area leading to large scale synoptic lift. Winds at 700 mb are 60 kts from the SW, which helps to maintain supercell structure by throwing the precipitation and associated cooler, stable air away from the potential supercell’s inflow and mesocyclone (lower rotating part that spawns tornados). Recent research suggests shear in the lowest 250 m above the ground is most important for tornadogenesis. The winds are 5 kts from due S at the sfc and 35 kts from the SSW at 950 mb! Considering a cold front is also slowing pushing through the area providing instability, we have the four ingredients for severe weather: Shear, Lift, Instability, and Moisture (SLIM).

The results are textbook supercell structures with strong, long lived tornados. Here is radar reflectivity as the tornado went through Mayfield carving a mile wide path of destruction through our commercial district. Notice the "hook echo" with a debris ball at its end. There is so much debris that a three point scattering spike (aka hail spike when only hail) extends to the SE of the debris ball. The tornado is at the inflow notch where the debris ball connects to the rest of the supercell and the velocity couplet is strongest.

The last component of any forecast is communication and associated actions. The synoptic forecast was more than adequate with an Enhanced Outlook (3/5) from the SPC and a Moderate (4/5) the morning/afternoon of the tornado outbreak. NWS Memphis and Paducah issued tornado warnings for the entire storm with often over 45 minutes of lead time. An additional Tornado Emergency for Mayfield with another 5 minutes of lead time (smaller red warning box in radar images). Yet, 50 people were killed when sheltering in the factory they worked in, following the NWS protocols of being in a building, interior room, lying or crouched down. Eventually, farmers will probably find the remains of the people whose solidly built houses are now just concrete slabs. I have read of similar situations for other EF-4 and -5 tornado fatalities where people follow these guidelines, which, I think, leads to meteorology as a whole needing to develop a new set of protocols for these extreme storms. Now that we can reasonably foresee such extreme tornado outbreaks hours to days in the future, we could have severe weather days where an entire region could plan to spend a few hours in designated regional storm shelters designed to withstand an EF-5 tornado. People are a society’s most important resource. Would foregoing one day of productivity every few years when an extreme tornado threat arises be worth avoiding a mass casualty event? Similar evacuation actions are taken for wildfires, hurricanes, and floods. Can we institute an action plan for rural, often poor areas in the Great Plains and South? If not, scotch yourself for more tornado fatalities where we sorrowfully stare at each other and think, “We did all we could,” or point our eyes skyward and simply question, “Why?”