Plains Bias in Severe Storms Forecasting?

Over the past 15 years I have had the privelege of traveling through almost all the states, and all the regions, of the continental U.S., for both official business and personal recreation. Business travel quite often takes me to local forecast offices and universities, since I am an atmospheric scientist specializing in severe storms. I’ve spent countless hours exchanging ideas about severe weather science and forecasting at these places.

Personal travel — in particular, storm observing — has taken me to field offices all over the central U.S. to interact with meteorologists as well. As a part of forecasting severe weather for the Lower 48, I communicate quite often with forecasters at local offices, whether for operational coordination or research questions, as well as private and media forecasters in all areas. And I’ve interacted with countless meteorologists in media, research and operational realms at regional and national meetings and conferences.

In all these meteorological interactions — public and private and from all backgrounds — one theme comes up more often than any other: a belief in “Plains Bias” in forecasting at the Norman based entity that predicts severe weather.

It’s an astoundingly common perception for which I don’t fully understand the origins. I can make some guesses based on crude psychological assumptions and totally unsupported speculations, but I won’t. Whatever the cause(s) of the idea, it really gets tiresome saying the same things over and over in refutational discussions about it, year in and year out.

Instead I’ll just engage this “Plains Bias” idea right here, once and for all, and illustrate it for what it is: A steaming heap of crap which is about to be resoundingly flushed into the sewer of meteorological mythology. Let’s start with some relevant geographics.

Here is a map showing the hometowns (not necessarily birthplaces, but usually) of all the full time forecasters and certified fill-ins at that unnamed national forecasting entity.

Hometowns of Severe Storms Forecasters

Given that these forecasters possess a lifelong love of weather in general, and violent weather in particular, the seeds of this interest sowed and sprouted in those hometowns, it’s quite the safe assumption that they have good familiarity with the nature of severe storms and other hazardous weather in those areas.

I lived in Missouri long enough to appreciate the motto of that state, so please show me the “Plains Bias” on that map. Sure, there are a few of us from Texas and Oklahoma, but if there is a concentration of hometowns it is subtle and shifted into the industrial Midwest instead.

Now let’s make the generally safe assumption that these meteorologists not only have dealt with weather regimes in the towns where they grew up, but in the universities they attended and the offices at which they performed meteorology in the past. “Offices” here includes locations where the same people served as forecasters, full time students or researchers before arriving in their current national forecast responsibilities.

Hometowns, Universities and Past Workplaces of Severe Storms Forecasters

There does appear to be a subtle “upper case gamma” or boomerang shape from Texas to the South Dakota – Minnesota line then east-southeastward across the Ohio Valley. Guess what: That’s the combined climatological distribution maximum for tornadoes and derechos. It’s natural and expected that folks interested in severe storms would gravitate to that boomerang. And yet…

Look at the geographic spread and diversity there! We’re talking Miami to Seattle, Vermont to Los Angeles — and regions of local expertise liberally sprinkled across the vast territory that lies between. Collectively, it’s glaringly apparent that these forecasters are familiar with weather over the entire conterminous U.S. The collective assumption is valid because these forecasters don’t live in a sealed vacuum of insularity and silence at work; they share their expertise with the others on a daily basis.

Now if one considers all the geographic areas of research study — places about which these forecasters have performed projects, theses and/or scientific papers — the rest of the lower 48 would be almost completely covered, as well as some adjoining parts of Canada and Mexico!

There is one concept in particular that cannot be stated enough to those who talk of a “Plains Bias.” The physics of the atmosphere does not change from place to place. The frequency with which certain combinations of those physics occur does vary geographically, but the basic laws of dynamics, thermodynamics and kinematics do not.

Give the atmosphere a specific combination of conditions and it will dump two inch diameter hail in Boston, Miami, Peoria, Glendive or Reno, and that two inch hailstone will have pretty much the same terminal fall speed and momentum when it hits the hood of a Honda Civic in any of those places.

Thunderstorm wind does have different effects from place to place, sure: from one house to the next, one block to the next, one tree to the next, one building to the next. Even within the same city, county, state or region, there are an infinite number of ways the same wind speed can do damage — or fail to do damage. Such is the variation in both human construction and vegetative stability. Yes, trees are more likely to fall in the shallow rooted sandy soil of southeast Virginia pine forests versus the brick-colored and brick-hard prairie clay of central Oklahoma, for example; but blowdowns have been documented from every part of the country.

If anyone has a “Plains Bias,” it may be a slant against the Plains by many meteorologists not residing there. Look how often, for example, New York City or Atlanta are mentioned on The Weather Channel as compared to Amarillo or Bismarck. Notice how much more press a small tornado in Washington DC or Miami gets than a huge one somewhere in rural Nebraska.

Surely there is less to damage in western Kansas than in Philadelphia, and surely there are fewer people, but tell me: Who is so arrogant as to say to that farmer outside Scott City that his life and property matters less than that of the chap munching cheesesteaks in the City of Brotherly Love?

Climatology tells us the relative frequency of those physical variations and the effects they yield. It illustrates (surprise, surprise!) that tornadoes hit most often in Oklahoma, with lobes extending east to Alabama and north toward Iowa. Significant-severe (two inches or larger diameter) hail hits the Great Plains more than anywhere. Derechos (organized convective windstorms) are most common from the Corn Belt to the Ohio Valley and in the southern Plains.

If anything has a “Plains Bias” for severe weather, it’s the atmosphere itself, not the forecasters. Yet because the physics of the atmosphere don’t change, any given severe weather event can happen anyplace in the U.S. And our job as forecasters is to make a best educated guess at where, when and how such events may be distributed on any given day.

For forecasters not located in the Plains, this so-called bias is a meteorological version of the tooth fairy, chains rattling in the attic, Will o’ the Wisp, Casper the Friendly Ghost or Peter Pan’s Neverland — fanciful fiction, pure artifice, a mythical thought-vapor with no basis or merit whatsoever.

As such, I hereby declare the myth of “Plains Bias” null, void, invalid and dead.


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