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Dallas tornado: Round one?

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You certainly heard about the Dallas tornado Sunday night and, if not, you can get the full story from Click2houston.com right here.

I want to explore the wind set up for this event because another front is headed into Texas on Thursday and a similar severe weather outbreak is possible.

One of the most important factors is the jet stream position. These are winds up around where airline passenger jets fly (33,000 feet) and are very fast (easily 100-125 mph). Consequently, they move wind quickly from UP TOP and air below will rush upward to fill the gap. Kind of like if you move your arm across the water at the top of a swimming pool, the water below rises quickly to replace it. Take a look at Sunday's Jet Stream:

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Right across North Texas! In addition, when those winds rush upward (known as vertical velocity) the horizontal winds coming in from different directions (in this case, SE, SW, W and NW) also increase and when you have different wind directions at different heights above the earth, that is when you get a spinning column of air: A tornado.

You can see these different wind directions last night from the 850 mb map (about 5000 feet above the earth):

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Those wind barbs clearly show the strong Northwest wind behind the red line and Southwest, then South winds ahead of it. That darkest red became the danger zone.

And as we head to Thursday, another front is headed into Texas:

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And look at the forecasted JET STREAM for the same time period. A huge dip south with cold air rushing to meet warm air and then bending quickly across Texas:

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So heads up for Thursday into Friday. The cold air off the Rockies brings a refreshing few days, but the severe weather set up is a big price to pay. 

I'm off today through Friday and headed south tomorrow where internet connections can be difficult, so have a safe week!! Go Astros!!

Frank

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