Tuesday, April 7, 2009

Severe Weather Aware...Thunderstorms

This is severe weather awareness week...so it is time to just go over a few basics of severe thunderstorms.

Lightning Facts:

-At any moment there are about 1800 severe thunderstorms moving over the Earth...annually about 16 million storms.

-Lightning is hotter than the sun. A bolt of lightning can be 50,000 degrees. That heat is what expands the air and creates thunder.

-If you hear thunder you are close enough to the storm to be hit by lightning.

-30 minute rule.... the moment you year thunder is time to go inside. Wait 30 minutes after the last clap of thunder to head back outside.

-If you hear thunder you are close enough to the storm to be hit by lightning.

In Iowa we are set up really well to see our fare share of severe storms. We have the moisture from the Gulf of Mexico that leaves us sweating with heat and humidity....to the north cold air that sweeps through with Canadian cold fronts. High winds are pretty familiar to most of us...that adds lift and momentum to the storms as strong lows pass overhead. The perfect storm effect is located right here.

When you hear or see a Severe Thunderstorm Watch issued for the areas... that means we are experiencing all those elements of strong to severe storms. It means you should be on the watch because conditions are right for the formation of storms that might be severe.

If you see or hear a Severe Thunderstorm Warning...that means a severe thunderstorm is going on right now. You need to seek shelter if that storm warning is for the area around your home or school or office.

New Severe Storm Criteria

This year new severe thunderstorm criteria was handed down from the Storm Prediction Center. Until now.. a severe thunderstorm with 3/4 inch hail was considered severe. Now the hail size for severe storms has been increased to 1 inch in diameter. This should help to reduce the amount of time we take crawling the severe warnings across the lower 1/3 of the screen. It's a good idea because we often cried wolf over storms that were strong...but not really severe. Remember this... if you are in a storm with 3/4 inch hail...it is still a strong storm. Make sure you have a place to hide from the elements of lightning...hail and heavy rainfall.

More Lightning Facts

The odds of getting hit by lightning are one in 5000. That means if you continually stood outside during strong storms... you would have the 1/5000 chance of getting struck by lightning. So don't just stand outside in strong storms... get in a building or a car. Do not stand under trees.. or near tall objects...or even an open shelter house. You need walls and a roof between you and the storm. If you are stuck outside and there is no way to get to shelter...crouch down on your tip-toes or the balls of your feet. Pull your head down to your knees. Don't lay down. Keep as little of your body as possible in touch with the ground. Lightning strikes spread out over the ground. The less of you touching the ground the better.

Severe weather is coming... it is our time... we are in the right place. Make sure you stay with Channel 13 and Iowa's Weather Plus on Ch. 13.2 or Mediacom Ch. 246 you will always see the warnings for our viewing area. You can also see the warnings on www.whotv.com and get weather all the time on your cell phone by signing up for weather information here: http://www.localwireless.com/wireless/signup.cfm?sid=73 You will see news and sports on your web-enabled phone too!

Keep a NOAA weather radio in your office...school and home. We have a portable model available at the Science Center of Iowa for $39.99 (same price the last three years!) It is perfect for you anywhere you go.

Be safe today and all year.

Ed Wilson

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