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TORNADO FAQs

Yes, but only to a limited extent. Although the process by which tornadoes form is not completely understood, scientific research has revealed that tornadoes usually form under certain types of atmospheric conditions. When forecasters see those conditions, they can predict that tornadoes are likely to occur. However, it is not yet possible to predict in advance exactly when and where they will develop, how strong they will be, or precisely what path they will follow. There are some "surprises" every year, when tornadoes form in situations that do not look like the right conditions in advance, but these are becoming less frequent. Once a tornado is formed and has been detected, warnings can be issued based on the path of the storm producing the tornado, but even these cannot be perfectly precise about who will or will not be struck.

You have to consider that the tornado is part of something bigger - the supercell thunderstorm. Unless you disrupt the supercell thunderstorm itself, you would likely have another tornado, even if you were able to destroy the first. The thunderstorm's energy is much greater than the tornado. No one has tried to disrupt the tornado because the methods to do so could likely cause even more damage than the tornado. Detonating a hydrogen bomb, for example, to disrupt a tornado would be even more deadly and destructive than the tornado itself. Lesser things (like huge piles of dry ice or smaller conventional weaponry) would be too hard to deploy in the right place fast enough, and would likely not have enough impact to affect the tornado much anyway.

The current average lead-time for tornado warnings is 11 minutes. NSSL is working to increase tornado warning lead-times to 20 minutes.

A tornado watch defines a box-shaped area where tornadoes and other kinds of severe weather are possible in the next several hours. It means that you need to be alert, and be prepared to go to safe shelter if tornadoes happen or a warning is issued. If you have a NOAA Weather Radio and have it set up correctly it will alert you to the watch. Tune in to local TV or radio for more information. A tornado warning means that a tornado has been spotted, or that Doppler radar shows a thunderstorm circulation which can spawn a tornado. When a tornado warning is issued for your area, seek safe shelter immediately. The Storm Prediction Center issues tornado and severe thunderstorm watches. Your local National Weather Service offices issue tornado warnings.

As far as scientists understand, tornadoes are formed and sustained by a purely thermodynamic process. As a result, their research efforts are towards that end. They have spent a lot of time modeling the formation of a tornado and measuring many parameters in and around a tornado when it is forming and going through its life cycle. They have not seen any evidence to support magnetism or electricity playing a role.

Unfortunately, government regulations make it impossible to accept offers from the public to do volunteer field work for any tornado intercept programs. Legal liability questions prevent NSSL from accepting volunteers, even at their own risk.

There have only been two strong La Niña events. Although scientists have looked for a correlation between La Niña and tornadoes, there just isn't enough data to make any conclusions.

Forecasting Tornadoes

Can tornadoes be forecast or predicted?

FORECAST MODELS

Forecasters often rely on massive computer programs called numerical weather prediction models to help them decide if atmospheric conditions will be right to support an environment in which tornadic storms might form.  The models start with current weather observations and attempt to predict future weather using physics and dynamics to describe mathematically the atmosphere's behavior.

WRF forecast model map of the US

WATCHES AND WARNINGS

Forecasters at the National Weather Service Storm Prediction Center (SPC) issue daily forecasts, or convective outlooks, for organized severe thunderstorms over the U.S. based on current weather observations and forecast models. They also closely monitor areas they think are at a higher risk for tornadoes.

If conditions develop that are favorable for tornadoes, SPC forecasters issue a severe thunderstorm or tornado watch that typically lasts four to six hours. Local forecast offices, emergency managers, storm spotters and the general public are alerted to the possibility of severe weather.

Tornado warnings are issued by the local National Weather Service Forecast Office when a tornado has been sighted or indicated by weather radar. People in the warning area should seek appropriate shelter immediately.

HOW DOES NSSL CONTRIBUTE?

NSSL is actively involved in refining and building new conceptual models of severe storms, supercells structures and mesoscale convective complexes and systems.  These conceptual models have improved our understanding of environments that are favorable for the formation of thunderstorms and tornadoes.

NSSL works with mesoscale models that help determine whether tornadic storms may or may not develop.  They then test to see if these models are actually helpful in an operational forecasting situation.

NSSL scientists are studying the technique of "ensemble forecasting." Ensemble forecasting involves running a large number of forecasts with different initial conditions or a large number of different models together. This appears to provide more accurate forecasts than a single model by itself. NSSL scientists have also experimented with using direct forecaster input to identify regions and conditions that seem to be at a higher risk of severe weather. This way the forecaster could use his judgment and experience and input it into the model before the computer begins its computations.

NSSL actively works with the Storm Prediction Center each spring to evaluate the usefulness of new developments in computer models in daily forecasting.

Hazardous Weather Testbed
Inspired by the mutual interests of SPC forecasters and NSSL researchers, the Hazardous Weather Testbed encompasses projects of many shapes, sizes and composition. Interactions range from daily map discussions involving imminent severe weather to loosely related research projects involving 2-3 collaborators to annual intensive collaboration periods such as the SPC/NSSL Spring Program. This relationship provides forecasting support for field research, helps evaluate operational and experimental numerical models and other emerging operational forecast tools, and transitions promising new meteorological insights and technologies into advances in forecasting hazardous mesoscale weather.

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