Lessons from the recent tornado outbreak – Are you interested in that?

news7g12/15/2021

5 5 minutes read

Lessons from the recent tornado outbreak - Are you interested in that?

Cliff Mass

A terrible tragedy struck Friday night, when powerful tornadoes hit a multi-state area from Arkansas to Kentucky. Initial estimates suggest that 50-100 individuals lost their lives and hundreds were injured.

A destroyed candle factory in Mayfield, Kentucky was badly affected
The death toll has certainly increased due to the nighttime occurrence of these storms and their development during winter, which is unusual but not unprecedented. The storms occur in two unified lines from southwest to northeast, as shown by tornado reports (red dot) provided by the NOAA/NWS hurricane forecasting center. For reference, the tornadoes hit Mayfield, KY around 10 p.m. Friday.

My colleagues at the National Weather Service (NWS), both at the Hurricane Forecast Center and local NWS forecasting offices (such as Paducah, Kentucky) did an excellent job in predicting threats and providing timely warnings and clocks before tornadoes occur.
Surely these ingenious forecasts and timely warnings have saved many lives. But they were not enough to prevent massive loss of life.
In this blog, I will review forecasts/alerts and suggest that new smartphone-based alert systems are needed and doable. Technology can save many lives from such severe storms.
National Weather Service Forecast
Earlier that day (1:17 PM), the Paducah National Weather Service’s Office noted that expected meteorological conditions were similar to previous cool-season tornado outbreaks (see below) .

Furthermore, around the same time, the NOAA/NWS Storm Prediction Center (SPC) issued a tornado watchdog that included Mayfield and other locations that were subsequently hit by tornadoes (see below) .

In the late afternoon, the clocks are repeated and hardened, and when severe thunderstorms, with supercell structure and rotation are developed, tornado warnings (indicating an impending threat ) has been announced (see below for 3:29 PM CST).

The tornado warning issued by the NWS Office in Paducah to Mayfield at 9:03 p.m. was excellent (see below). This warning was issued about 30 minutes before Mayfield was devastated.

I can show you many NWS forecasts, model predictions and more… and you will be impressed. The area has been given clever and timely warnings of the potential for powerful, damaging tornadoes. NWS forecasters and NOAA/NWS Hurricane Center staff can be proud of what they’ve done.
But many people still die.
I suggest that this technology exists to substantially reduce the risk of tornadoes. A technology that I’ve been thinking about for quite some time: automaticalert system based on smartphone, controlled by observations of science. But first, let’s talk about the nature and limitations of severe hurricane and tornado forecasting.
Limitations of tornado forecasting
Technology to predict severe thunderstorms has come a long way over the past several decades. Meteorologists have high-resolution forecasting models (such as NOAA/NWS High-Resolution Rapid Refresh HRRR), improved satellite systems, and meteorological radar that enhance structural knowledge. and the evolution of severe convection and machine learning techniques now support severe storm prediction (see model projections below).

HRRR Model Forecast 9 a.m. NOAA/NWS at 03 UTC, Dec. 11 (December 9 p.m. CST)
Improved models and forecast guidance help meteorologists recognize threatening situations and predict the arrival of severe storms for an area. However, about three hours or more, Our models cannot accurately predict the location and intensity of impending severe storms. Only when hurricanes have developed and are moving on a clear path can forecasters make detailed forecasts of tornado occurrence and tracking… .and even then, only within next few hours.
I should note that the NWS tornado warning has a False Alert Rate (FAR) of about 70%. So about 70% of warnings don’t appear.
From experience, people and businesses know that forecasts are not perfect and therefore do not necessarily act promptly or effectively to shelter in place or move away from the threat. And then there’s the matter of communication… .they may not even be aware of the threat…. especially a problem for storms at night.
Predictability of recent events
An important point about the recent event is that tornadoes are long-lived and travel on a relatively straight, continuous path. Large, intense tornadoes are often associated with supercell thunderstorms with alternating winds. We can see large areas or rotations using Doppler radar, which tells us the velocity to or from the radar of precipitation relative to the storm.
As shown in the figure below, alternating colors (in this case red and green) in a small region are indicative of rotation in a radar-based Relative Storm Motion (SRM) image:

This is an animation of the SRM image from the Paducah radar in the period before the tornado hit Mayfield. Rotational start is moving straight to NW with little magnitude change.

We can track this rotation over time, and in doing so, the path of the hurricanes’ rotation in the period around Friday night’s worse tornado is shown below. You can see the amazingly straight line of the narrow turns extending from Arkansas, to Tennessee and Kentucky. There is also a roundabout in relation to other severe storms to the north.

The point of all of this was that simple extrapolation of the severe storm’s motion provided an excellent short-term forecast for the event over the next hour or so.

Tornado guidance must be made available in real time to individuals or businesses so they can make instant, optimal decisions to save lives and property. For tornadoes, people must determine if they are threatened, and if so, should shelter in place or stay out of the storm.

Smartphone-based tornado warning app

Most people have smartphones and such phones know their exact location since they have GPS.

Obviously, we can now deliver National Weather Service forecasts, including tornado warnings and warnings, to smartphones, providing location-appropriate forecasts. mentioned. This is low fruit…and obvious.

But in operational scenarios, things are happening so quickly and locally that NWS forecasters can guide people… .automatic software has to take over.

By using Doppler radar imaging (available approximately every 5 minutes), the instantaneous path of the storm can be determined in real time, and the location and path of the storm can be provided on electricity. smartphone, with continuously updated information about the probability that the smartphone’s location is being exceeded. Estimated arrival times may be noted.

But there’s more than that. Modern radars can also track the debris cloud of large tornadoes… .and thus have confirmation of the tornado’s position and motion

Smartphones can not only provide warnings of an impending tornado, but can also provide information on the best direction to flee if shelter is unavailable – usually at right angles to the road. away of the storm. Distances of several thousand feet can make a huge difference if there is no place to hide.

It is also possible that the THEMSELVES smartphone can provide important weather information to facilitate the determination of the location and movement of tornadoes. Many smartphones have very capable pressure sensors, which I know because I have been researching the meteorological applications of those sensors for over a decade.

Cyclones have a large pressure signature, and smartphones can collect and communicate those pressures in real time. Such smartphone pressure observations could be used by automated systems to determine the intensity and path of tornadoes, and thus improve guidance for individuals making decisions important determination.

I tried talking to Apple and Google about helping to collect pressure data on smartphones to improve weather forecasting. So far, they have listened politely and done nothing. Perhaps that could change. Or perhaps Amazon can help.

In short, a smartphone app, applying real-time meteorological data, can provide particularly valuable guidance during tornado outbreaks and could save lives.

It can be done. And I suspect that only a government organization would take on this because of liability concerns.

Source link

news7g12/15/2021

5 5 minutes read