Since you are the only person I know who has any expertise in this area.

I drove through and incredibly scary storm in Chicago a couple of days ago. The sky was black, it felt like night even though it was 3 in the afternoon. The wind was crazy and it was raining so hard it was coming down in sheets and I could not see more than 2 feet in front of my car.

I am terrified of tornadoes and was so worried that there might be one and since I could not see due to the rain I would not be able to see if there was a tornado.

When I got home a friend of mine told me there cannot be a tornado if it is raining.

Is that true? If it is raining can there be a tornado? I live on the prairies and there are quite a few tornados that touch down here yearly but I have never heard this before.

Thanks.

Hi Cherri,
Tornadoes do occur when it is raining...it all depends on where the tornado actually occurs with regards to the storms position. A 'supercell' thunderstorm has one single, rotating updraught. Wind shear is bascally where the wind turns with height as you move through the atmosphere. If you have the right atmospheric set up in place, a strong enough thunderstorm updraught can be affected by this wind shear so that is starts to rotate. If this updraught is persistent and robust enough it can extend to the ground, which is where you get your tornado. There are three main types of supercell...LP (low precipitation) HP (High Precipitation) and Classic (a balance somewhere inbetween LP and HP) Some tornadoes can actually become wrapped in the rain core of a HP supercell and so are not visible, clearly these can be incredibly dangerous because to the untrained eye, they can be completely hidden.
So, without getting too technical, you friend is unfortunately wrong! The precip area of a storm can sometimes shield the tornado from you, depending on your vantage point. I have seen enough HP supercells to know that they are certainly something to be wary of...always listen to that weather radio when there is a storm around, just to make sure that there are no warnings out on it.

thanks Storm.

I'm glad nothing like that happened, it sure was a scary storm though.

hm very interesting storm, i've always been intrigued by weather :)

I definately agree that tornados occur when it is raining.. "Twister" anyone? A great movie with Helen Hunt...and if i saw it in a movie it must be true! hehe

One thing i know is that if you are in a storm and it gets eerily calm..it is time to hide! Eye of the storm can be a dangerous place to be. B)