Sunday, November 6, 2011

Threat of Storms

We are less than 25 days from the start of meteorological winter but we need to be thinking about spring... spring storms.

I have talked about the chance for colder air moving south out of the arctic in the next week and a half. Ahead of the colder air it appears we will have a chance for strong thunderstorms across the middle United States.

The Storm Prediction Center has included parts of Missouri, all of Arkansas and places further south in a "Slight Risk" for severe weather 7am Tuesday through 7am Wednesday.


An area of low pressure is going to develop over New Mexico and Texas over the next two and a half days.


Strong winds in the jet stream will rotate around and provide lift in the atmosphere. By mid to late afternoon Tuesday I expect to see thunderstorms developing over eastern Oklahoma, western Arkansas and western Missouri. The thunderstorms should develop in to a line of storms that will move east across Missouri, Arkansas and further south.

I have been looking over the morning run of the GFS and NAM computer models. There are a few subtle differences between the models but both appear to be pointing at diverging winds at the 300mb level over southeast Missouri by Tuesday evening/night. The NAM keeps winds a little more divergent over Arkansas and the GFS keeps winds a little more divergent over southern Illinois.

Here is a look at one of the computer models. This indicates winds at 300mb (approximately 30,000 feet) 7pm CT Tuesday.


I look for divergent winds at 300mb because that gives an indication if there will be lift in the atmosphere. Diverging winds create a void and wind from below lift in to fill the void.

All of the above said, it looks to me there could be strong to severe storms along the line of storms as it moves through Arkansas and Missouri. It is still a little early to nail down the main threat from the storms but it damaging winds, isolated tornadoes and hail all could be possible.

Stay tuned...
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Daylight Saving has come to an end. Hopefully you remembered to change the times on your clock this morning.

Fire departments across the country use the time change as an opportunity to remind everyone to replace the batteries in your smoke detectors. This is good practice. I want to suggest you take it a step further and use the time change as an opportunity to replace the batteries in your NOAA weather radios.

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