Warm Winds And StormsSeptember 18th, 2012 at 8:42 am by Jeremy Wheeler under Weather
Today is going to be much different than the last few days in terms of weather. It will be very warm, very windy, and humid. This is all out ahead of a strong cold front which has been developing across the Midwest. We have some strong upper level winds as well from Ohio to the Mid-Atlantic. The front will make it to eastern Kentucky/Tennessee later today. There will be a potent low level jet (core of faster winds) out of the south which will allow the warmth and humidity to keep building across the east coast through the day.
While the bulk of the storms will stay west of us until later in the afternoon, we will catch some isolated-scattered fast-moving showers coming up from the south for at least the first half of the day. Yesterday, the models had almost all of the rain holding off until this evening. Today’s models are showing some of the storms pushing in from the southwest by the mid afternoon. Here is our model (Future Trak) at 3pm:
By tonight the cold front will make it into western and central Virginia/North Carolina. This will focus the storms over the viewing area, and that is expected from around 8pm until about 1am. The chance for rain will be 50% from noon until about 4pm. 70% chance from 4pm until about midnight.
By early tomorrow the cold front will move through. It will change the breeze to out of the north. Gusts will be up to 25mph. Some of the moisture will linger though. So we will have a few early showers and lots of clouds through the day. An afternoon sprinkle is possible. Then we’ll see some nice weather on Thursday and Friday.
So as far as the severe weather threat goes. We are under a slight risk for today. Mostly for late this afternoon into the evening.
Typically with areas of low pressure that move from the Tennessee Valley north into the Great Lakes we don’t usually get too much severe weather here in Hampton Roads. Usually the upper level support will move away from us and the front will move through with only a quick burst of winds. In this case we will have a long period of warm/moist air out ahead of the system. Plus the upper level winds do try and move back closer to us with the front this evening. So it’s not a typical situation. We are expecting lots of clouds today. So that should help a little with the instability. However, there will be some breaks in those clouds as we’ve already seen this morning. So we will at least have some low-moderate instability. As mentioned the upper level wind support (wind shear) will be very impressive just west of our area (Up to 55 knots). Those strong winds will migrate from central Virginia up to Maryland and Pennsylvania this evening according to the models. It will increase again to the southeast by around midnight. This will be able to support the strong/severe storms tonight. The main threat will be straight-lined winds, but an isolated tornado is also possible. The heaviest rain is expected over western Virginia where 2-4″ of rain is forecast. Locally we are looking at a general quarter to half inch of rain, but some locations will be able to get over an inch.
There’s no big update with tropical storm Nadine. It will brush by the Azores islands, but now it looks like it will push a little more to the south over the next couple of days.
Stay tuned to the weather today. There will be some important updates. Especially by midday. I’m looking forward to the cool-down again tomorrow. Plus, my yard could use a little rain at this point. Hopefully, the strongest winds are brief.
Meteorologist: Jeremy Wheeler