Thursday, April 28, 2011

Sadly, storm specialists were correct again

If the Storm Prediction Center in Norman, Okla., ever puts your area at "high risk" of severe thunderstorms or tornadoes, go look for shelter.

The meteorologists in Norman once again nailed the forecast Wednesday, correctly predicting the massive outbreak of tornadoes that killed about 200 people. It's the second time this month that one of their rarely issued "high risk" forecasts panned out.

When severe weather is a possibility, the Storm Prediction Center classifies areas as being at "slight," "moderate" or "high" risk of storms. The "slight" risk classification is used most of the time. Occasionally -- maybe a few times a month -- they'll use the "moderate" tag.

According to a list I found, the "high risk" classification has been used 86 times in the last 27 years. By my Cleveland State math, that's about three times a year, so it's rare.

They've issued a "high risk" three days this month -- but, actually, for two events.

The first was April 16, when the Oklahoma-based meteorologists predicted a major tornado outbreak in eastern North Carolina and southeast Virginia. The result: dozens of twisters that killed more than 20 people. It was one of the worst tornado outbreaks in Carolinas history.

Then the Storm Prediction Center used the "high risk" tag on Tuesday and Wednesday -- Tuesday for the Arkansas and Texas area that was clobbered by tornadoes and flooding that day; and Wednesday for northern Alabama, southern Tennessee, northeast Mississippi, and northwest Georgia.

Thursday's forecast turned out to be the bulls eye for the storms that will turn out to be the deadliest in decades.

The risk classification is based on a number of factors -- the amount of lift in the atmosphere; helicity, or the spinning motion of the atmosphere; and shear, which is the term for winds blowing from different directions at various levels of the atmosphere.

They don't bat 1.000 in Norman, but the Storm Prediction Center scientists have a pretty good average. And this month, they've been incredibly accurate.


Adam Hefner said...

Why not just issue all high risk if there's even a possibility. I know it may cause some headaches but atleast more will be aware. I know I was when were under high risk here in Raleigh.