We've made it to February and we can say that the Charlotte has been put under it's first Slight severe risk of 2017. What does this mean and what can you expect?
Well, for us that means that there is a 10% chance of severe weather within 25 miles of any point in the highlighted location. This is pretty low in (only 2 out of 5 levels of severity) the scheme of things so i wouldn't exect widespread severe weather tonight over the area.
Now for the fun part the analysis. Looking at the 18Z run of the RAP model, it looks around 06Z (or 1AM) CAPE values will be at their highest for the Charlotte region. CAPE is the amount of energy available to lift air upwards, this is important because for storms to form you need air to move up from the surface. Levels of 1000 J/Kg of CAPE and higher are normally considered to indicate severe weather is possible but the RAP is showing around 300 J/Kg for Charlotte during this time.
So what else do we take into account for when looking for the possibility of severe weather? One thing we can look at is shear in the atmosphere. This is directional changes in wind as you move up in the atmosphere. Normally higher levels of shear will be more conducive for severe weather. Amounts of 40 knots of shear normally indicate the possibility of severe weather and the RAP is showing us with about 69 knots of shear. Because of this, we can somewhat get past the fact that there is less CAPE in the atmosphere than what we need.
Going off of the 18Z HRRR run, we can see the storms moving through the area from 1AM till about 4 AM. With this being said the amount of storms and how strong they are will be based off of how they fire up today over Georgia and Tennessee. If things don't get started in the afternoon or evening I don't think we will have as high of chances of seeing severe weather.
So What are the Risks?
My thinking is the timeslot for Severe weather over North Carolina will be between 8PM and 1AM (going from the mountains- eastward). Althought there is a extremely small threat of Tornados in the mountains I think that statewide our biggest threat is going to be straight line winds (winds greater than 60 mph) and the chance of hail will also be pretty small during this event.