Updated Tornado Outlook for Saturday

Well, we've gone from bad to worse with the addition of maxed-out probabilities in eastern Nebraska and the extension of the hatching farther east.

Sixty percent is the highest the numbers can go. If you live in the hatched areas keep up on the weather tomorrow and tomorrow night! Hatched areas are where violent tornadoes may occur along with winds of 75 mph or higher and/or hail 2" in diameter or larger.

Now, I want to show you an index that can help discern where the strongest tornadoes might be:

A value of "1" is generally considered sufficient for adequate for "significant" (defined by meteorologists as a tornado of F-2 intensity or greater) tornadoes. In this case, values max out at 5 just southwest of Wichita at 7pm Saturday. Do not consider these exact locations. I'm simply trying to establish that both the computer values and the human forecasters consider tomorrow to be a dangerous day.

My advice for tomorrow if you live in one of the moderate or high risk areas? Go about your routine checking the weather every hour or so unless thunderstorms start to approach. At that point, pay continuous attention. Use good sense and you'll be fine.

Here are the most current tornado safety rules.

And, if you must travel tomorrow, here is a list of exact public shelter locations along the Kansas Turnpike. However, I strongly advise against driving (except to get yourself home or to a public shelter) once a tornado watch has been issued.

Speaking of driving, there will lots of tornado chasers in the 60% areas tomorrow. Some of them are conducting important research. Please understand that a lot of what we know about tornadoes -- and how to warn of them -- has come from the chase program.


  1. I strongly advise against driving (except to get yourself home or to a public shelter) once a tornado watch has been issued.

    Seriously? No driving in a tornado watch area? I totally get that for a warning, but a watch? There are some months I wouldn't be able to drive at all what with the watches.

  2. Tomorrow is a unique day. Only one other time in the 16 years of probabilistic tornado outlooks have the probabilities been maxed out 36 hours in advance. The other time there were 16 fatalities.

    The watches tomorrow will be of the rare "particularly dangerous situation" (PDS) type (I'm confident) and the storms in Kansas and northern Oklahoma will have forward speeds of 50-55 mph in places. Those cannot be outrun by a car.

    So, yes, tomorrow: Get home or other safe place once the tornado watch is issued if it is a PDS tornado watch.

  3. Mike, do you mind identifying which index you are looking (if you can)? I grew up watching you as a boy on television in southwest Kansas. I still have a lot of family in Kansas that I am getting concerned about, even though I am over here in central Illinois now.

  4. Sure, RedDog. The red "dot" is a value of 5 on the 0-1 km Energy-Helicity Index. A value of 2 or more is indicative of violent tornadoes. For example, according to this blog, the Greensburg tornado had a value of 5 ( www.jondavies.net/050407greensburg/050407greensburg.htm ).

    Don't take the value and the location of the dot too literally. If your family monitors the weather and takes proper precautions (scroll down for most current version of the tornado safety rules), I'm sure they'll be fine.

  5. This seems to fly in the face of your earlier stated opposition to the new, more complicated system of watches and warnings. I agree that adding that extra complexity is counter-productive. What changed your mind?

  6. Monster: don't understand your question. I haven't said anything about warnings in this post. I'm talking about watches.

    Please clarify if I am missing something.

  7. So your opposition is to having more than one kind of warning, but you support having more than one kind of watch?

  8. Monster: Absolutely, for two reasons.

    1) A watch is issued hours in advance. That allows TIME to convey information and allows times to adjust (i.e., cancel your children's soccer game).

    2) A warning means IMMEDIATE ACTION is needed. And, in the case of the warning the action we want people to take is exactly the same (go to the basement and get under the stairwell or heavy furniture, etc.) whether it is an F-1 or F-5. Trying to explain the difference between a "particularly dangerous situation warnings" or a "tornado emergency warning" wastes time and makes zero difference as to the action we want people to take.

  9. Thanks for the clarification. Put that way, it makes perfect sense.

    I heard on the TV a while ago that several SE KS high school proms scheduled for tonight have been moved to stronger buildings, presumably strong enough that no one need leave one of the buildings if a warning is issued. It makes one wonder about the wisdom of scheduling any large number of people to be in a weaker building in SE KS on an April evening in the first place.


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