87
      Saturday
      83 / 67
      Sunday
      84 / 70
      Monday
      89 / 73

      Tuesday Severe Weather: The latest risk and timing

      10:00PM Update:{} No reason to change this.{} Risk of severe weather for Tuesday continues.{} Damaging winds LATE and will increase risk of small whirlwinds but risk of large tornadoes very low.{} The late outlooks from Storm Prediction Center remain the same

      Usually when we get into mid-September the chances of severe thunderstorms diminish.{} But Tuesday, the combination of a storm and rain moving near us and a strong cold front moving in from the west, will generate a combination of rain and likely strong winds and what is called "shear" in the air above us.{}

      All likely to combine to bring a high risk of strong and perhaps damaging winds.{} Here is how we see the risk of tornadoes, wind, hail and flooding for Tuesday.{}

      The National Weather Service Storm Prediction Center{}has the D.C. area right at the center of a 30 percent probability of severe weather Tuesday.{}{}

      Here is one of the the things that show us the risk of severe weather Tuesday. It's a "model" or simulation of the temperature, moisture and wind profile above us Tuesday afternoon.{}{}

      I've circled the winds near the surface and about 3 miles above us.{} You can see the very moist winds from the south at the surface and the indication of winds about 75 mph above us and from the southwest.{}{}

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      The combination of the change in wind speed with height, and the change in direction is what is wind shear and one of the indications of possible severe weather.{} The very latest from some of the ensemble simulations at the Storm Prediction Center also do show a risk of possible small tornadoes because of all the shear or spin in the atmosphere.{}

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      No sign of a big outbreak, but even rotating rain showers can generate a small tornado or whirlwind in our area. {}More to come and we will also be live blogging starting Tuesday morning to keep you posted and any severe warnings go out immediately on our @StormWatch7{}Twitter account.{} We will keep you informed.

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