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Timing of widespread wave of strong storms in the Midwest is ‘very unusual’

November 18, 2013 at 12:00 AM EST
The string of storms that devastated the Midwest over the weekend was very rare for the timing, both time of year and time of day. Gwen Ifill talks to Howard Bluestein of the University of Oklahoma about the special conditions that triggered the deadly tornadoes.
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GWEN IFILL: The tragedy left many questions about the questions about the intensity and the volume of the twisters, as well as the unusual timing.

For answers, we turn to Howard Bluestein, a professor of meteorology at the University of Oklahoma.

Thank you for joining us, Professor.

We just saw that map in which — all of those reported tornadoes throughout the entire Midwest. How unusual was it to see a wave of storms like this?

HOWARD BLUESTEIN, University of Oklahoma: Well, it’s very unusual to see a wave of storms like this, this time of year.

This is something that we expect might happen in march or April. But it’s extremely unusual to have such a widespread outbreak in the Midwest in November.

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GWEN IFILL: Well, let’s walk through some of the unusual features here. When was the time of day when these tornadoes struck? We’re kind of used to hearing about late-afternoon warnings that come, touchdowns of tornadoes, but not an early morning one.

HOWARD BLUESTEIN: Yes, this was extremely unusual. I believe the storms began around 9:00 in the morning. And, usually, we need to get the sun’s heating during the day to get the storms going.

But, in this case, a very, very powerful storm system came through that lifted the air very, very early. And we didn’t need to get to be very warm for the storms to be triggered.

GWEN IFILL: How about the time of year? We just heard the mayor of Washington, Illinois, saying,it’s not construction see son, it’s not the time when they are usually building houses. In fact, it’s — we’re on the lip of winter.

How unusual was it for to us to see tornadoes like this touch down this time of year?

HOWARD BLUESTEIN: Well, I think this sets an Illinois record for the number of tornadoes in November. This time of the year, in mid-November, we expect to see snow starting to fall. But, instead, the very, very warm air came up from the Gulf of Mexico. The moisture came up from the Gulf of Mexico.

And, this time of year, it usually doesn’t make it that far north.

GWEN IFILL: So do we have any reason understanding — way of understanding why it did this time?

HOWARD BLUESTEIN: Well, I think this may have been just one unusual event.

A storm system came in on Friday, an upper-level storm system, moved in from Canada into the Pacific Northwest. It tracked across the country. And just before it hit Illinois, when it was over Iowa, it rapidly amplified and intensified. And so I think that was what was mainly responsible for producing this particular outbreak.

GWEN IFILL: I have seen reports of everything from a couple of dozen to 42. We just saw 80 reported tornadoes touching down in that region, all those dozen states. Do we have a count? Is there any way to know what the count is?

HOWARD BLUESTEIN: We don’t have a good count right now yet. There may have been 80 or more reports of tornadoes. But many of those reports were from the same tornado as it moved along a path.

So I expect that the National Weather Service will probably go out and do damage surveys, and after the damage surveys, we should know how many tornadoes there actually were.

GWEN IFILL: In terms of intensity and speed and scope, how does this compare to other weather events like this we have seen, especially tornadoes in the Midwest?

HOWARD BLUESTEIN: Well, this is not one of the most intense outbreaks we have ever seen. There were no EF-5 tornadoes, as far as I know, although after the damage survey, it’s possible that they may find some evidence of EF-5 damage.

But one thing that was special about these particular tornadoes was that they were moving very quickly from southwest to northeast. And if they are moving at 50 miles an hour, that adds 50 miles an hour on to whatever speeds are of the tornado vortex. So that may have also contributed to the intensity of the tornadoes being relatively high.

GWEN IFILL: Even though eight people, sadly, died, there was a lot of damage. Was there a lot of alerts that went out in advance that prevented this from having been worse?

HOWARD BLUESTEIN: This particular event was extremely well forecast by the National Weather Service. The night before, the National Weather Service issued a public statement warning the public of a possible severe weather outbreak.

And early in the morning, very early in the morning, a high risk of severe weather was issued. This is the highest level that can be forecast and issued.

GWEN IFILL: Well, it’s good that they had some warning, at least.

Professor Howard Bluestein of the University of Oklahoma, thank you so much.

HOWARD BLUESTEIN: You’re welcome.