Tornado forecasting How are tornadoes detected or forecasted Severe Weather

Tornado forecasting : How are tornadoes detected or forecasted? (Severe Weather)

In this article I will talk about ” Tornado forecasting : How are tornadoes detected or forecasted? (Severe Weather) . Keep reading to get yourself knowned and updated about this phenomena.

Who forecasts tornadoes?

In the U. S., only the National Weather Service (NWS) issues tornado forecasts nationwide. Warnings come from each NWS office. The Storm Prediction Center issues watches, general severe weather outlooks, and mesoscale discussions. Tornadoes in Canada are handled by the Meteorological Service of Canada. Very few other nations have specific tornado watch and warning services.

How do you forecast tornadoes?

This is a very simple question with no simple answer! Here is a very generalized view from the perspective of a severe weather forecaster: When predicting severe weather (including tornadoes) a day or two in advance, we look for the development of temperature and wind flow patterns in the atmosphere which can cause enough moisture, instability, lift, and wind shear for tornadic thunderstorms. How are tornadoes detected or forecasted .

Those are the four needed ingredients. But it is not as easy as it sounds. “How much is enough” of those is not a hard fast number, but varies a lot from situation to situation, and sometimes is unknown! A large variety of weather patterns can lead to tornadoes; and often, similar patterns may produce no severe weather at all. To further complicate it, the various computer models we use days in advance can have major biases and flaws when the forecaster tries to interpret them on the scale of thunderstorms.

As the event gets closer, the forecast usually (but not always) loses some uncertainty and narrows down to a more precise threat area. [At SPC, this is the transition from outlook to mesoscale discussion to watch.] Real-time weather observations–from satellites, weather stations, balloon packages, airplanes, wind profilers and radar-derived winds–become more and more critical the sooner the thunderstorms are expected; and the models become less important.How are tornadoes detected or forecasted .

To figure out where the thunderstorms will form, we must do some hard, short-fuse detective work: Find out the location, strength and movement of the fronts, drylines, outflows, and other boundaries between air masses which tend to provide lift. Figure out the moisture and temperatures, both near ground and aloft, which will help storms form and stay alive in this situation.How are tornadoes detected or forecasted .

Find the wind structures in the atmosphere which can make a thunderstorm rotate as a supercell, then produce tornadoes. [Many supercells never spawn a tornado!] Make an educated guess where the most favorable combination of ingredients will be and when; then draw the areas and type the forecast. For a graphical overview of the SPC forecasting process, see this poster by Steve Corfidi.  That sounds really hard.

What hardware and software tools do you use to help you forecast tornadoes?

The most important hardware for forecasting at the Storm Prediction Center is the human hand. Numerous hand-drawn analyses of surface and upper-air data are still performed at SPC every day so forecasters can be intimately familiar with the weather features. SPC forecasters also use high-performance computer workstations (mainly running Linux and Windows), with a huge variety of software to display the things we need to help us forecast severe weather.

The variety of those things is enormous: many kinds of computer model displays, satellite image loops, radar displays, wind profiler and radar-wind plots, data from surface weather stations, upper air data from balloons and planes, lightning strike plots, weather data tables, multiple-source overlays, and more.How are tornadoes detected or forecasted .

It may sound trite; but by far, the most important software in the tornado forecast process is within the human brain. The forecaster must use it to sort all that information, toss out what is not needed, properly interpret what is needed, and put it into a coherent form–all on a time deadline.How are tornadoes detected or forecasted .

What is needed to be a good tornado forecaster?

It all starts with… Motivation: Almost all severe storms forecasters are passionate about violent weather, with an intense desire to learn about and become better at predicting it. For many, this dates back into childhood–a first-hand encounter with violent storms, images on TV or in books and magazines, or even a deep attraction to storms that goes back too far to recall. Others start out in other fields or college majors, and then became fascinated with severe weather.

In any case, this desire leads to… Education: Consistently good severe storms forecasters have a solid educational background in atmospheric science which allows them to understand “textbook” concepts of thunderstorm formation. They don’t stop with their college education, either. They constantly re-educate themselves in the latest discoveries about severe thunderstorms and tornadoes– reading scientific journal articles on cutting-edge research, perhaps doing some research themselves.

The understanding of storms which results lets the forecaster think of “conceptual models”–visualizations of what the storms will do and how. Flexibility: Because the atmosphere doesn’t read textbooks or science journals, the forecaster must adapt those “classroom” ideas to an endless variety of day-to-day situations which may look a lot different. He or she also should be able to recognize when and why a forecast is not working out, and make the right adjustments.

These skills come from…  Experience: In meteorology, history never repeats itself exactly. But certain types of situations do recur, allowing the forecaster to set a mental benchmark for what to expect. From there, he or she can better decide what data will be most important to examine, and what data will not be as relevant to the situation.How are tornadoes detected or forecasted .

Experienced forecasters are able to learn how bad forecasts went wrong and how good forecasts worked each time, building a more complete mental warehouse of severe storm forecast knowledge as time passes. When the experience is continually blended with motivation, flexibility and more education, he or she will keep improving as a forecaster.

What is the tornado forecast for next spring?

Are there going to be tornadoes in Iowa the week of next October 5? We just don’t know. Tornado forecasting today and tomorrow is quite difficult already. Specific severe weather forecasting more than days in advance is little more than guessing, or using tornado climatology for the forecast area and time of year. For that reason, there is no such thing as a long range severe storm or tornado forecast.

There are simply too many smallscale variables involved which we cannot reliably measure or model weeks or months ahead of time; so no scientific forecasters even attempt them. Perhaps, someday, the density of weather observations and atmospheric modeling capabilities will advance enough to allow us to do severe storms forecasting many days out with some degree of accuracy better than a coin toss. We are a long, long way from that kind of forecasting!

What is the role of Doppler radar in tornado forecasting?

Each NWS forecast office uses output from at least one Doppler radar in the area to help to determine if a warning is needed. Doppler radar signatures can tell warning meteorologists a great deal about a thunderstorm’s structure, but usually can’t see the tornado itself. This is because the radar beam gets too wide to resolve even the biggest tornadoes within a few tens of miles after leaving the transmitter.

Instead, a radar indicates strong winds blowing toward and away from it in a way that tells forecasters, “An intense circulation probably exists in this storm and a tornado is possible.” Possible doesn’t mean certain, though. That is why local forecasters must also depend on spotter reports, SPC forecast guidance on the general severe weather threat, and in-house analysis of the weather situation over the region containing thunderstorms, to make the best-informed warning decisions.

What was the first successful tornado forecast?

Nobody knows when was the first time someone claimed a tornado would occur in an area, and it happened. But the first documented, successful tornado forecast by meteorologists was on March 25, 1948, by Air Force Capt. (later Col.) Robert Miller and Major Ernest Fawbush.How are tornadoes detected or forecasted .

After they noticed striking similarities in the developing weather pattern to others which produced tornadoes (including the Tinker AFB, OK, tornado several days before), Fawbush Page34 and Miller advised their superior officer of a tornado threat in central Oklahoma that evening.

Compelled from above to issue a yes/no decision on a tornado forecast after thunderstorms developed in western Oklahoma, they put out the word of possible tornadoes, and the base carried out safety precautions. A few hours later, despite the tiny odds of a repeat, the second tornado in five days directly hit the base. For more insight into this event, Charlie Crisp has transcribed the late Col. Miller’s recollections of the event; and they are now online.

What is the history of tornado forecasting?

It’s too long and eventful to summarize here; but there is an online guide at NSSL, as well as a timeline of SELS and SPC, and a history of the SPC that provide insight into how tornado prediction has evolved. There is also an entire book devoted to the subject: Scanning the Skies : A History of Tornado Forecasting by Marlene Bradford (hardcover – March 2001). Some libraries, bookstores and online book sellers carry this comprehensive and detailed history work.

Was tornado forecasting once banned in the U. S.?

Yes. Before 1950, at various stages of development of the Weather Bureau, the use of the word “tornado” in forecasts was at times strongly discouraged and at other times forbidden, because of a fear that predicting tornadoes may cause panic. This was in an era when very little was known about tornadoes compared to today, by both scientists and the public at large.

Tornadoes were, for most, dark and mysterious menaces of unfathomable power, faststriking monsters from the sky capable of sudden and unpredictable acts of death and devastation. As the weather patterns which led to major tornado events became better documented and researched, the mystery behind predicting them began to clear–a process which still is far from complete, of course.

In 1950, the Weather Bureau revoked the ban (PDF) on mentioning tornadoes in forecasts. How has SPC performed with tornado forecasting? By most measures, SPC (formerly SELS, NSSFC) has improved its tornado forecasting over the past few decades. There are many ways to objectively gauge forecast performance–for example, verifying tornado watches with tornado reports and both watch types by all severe reports. The general trend from 1985 onward has been for a greater percentage of tornado watches to contain tornadoes.

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