The Storm Prediction Center (SPC) in Norman, Oklahoma has placed the Tennessee Valley under a slight risk for severe weather. The SPC is responsible for issuing Tornado and Severe Thunderstorm watches. They issue the risk areas based on forecast parameters reaching specific values that have a history of producing severe weather. Severe weather is defined as Tornadoes, quarter sized hail or larger and or straight line wind 58mph or greater. The risk categories are slight, moderate and high. The threat for significant severe weather goes up based upon this risk assesment. I don't expect us to see an upgrade to a moderate risk but there is a threat for nickel sized hail, wind gusts over 58mph and isolated tornadoes late tonight and very early Saturday morning. The cold front will pass through before the Noon hour and tempeatures will begin to fall into the 40s for the rest of the day on Saturday.
The area in yellow below is the area under the Slight Risk tonight.

Temperatures early Saturday morning will be well above normal due to the amount of moisture in the air.

Pinpoint Predictor is showing a line of storms beginning to form ahead of a cold front after Midnight tonight. This line will likely begin to intensify and track slowly to the east. It will producing very heavy rain along it's track. Rainfall totals beteen .75" and 2.00" could result in flash flooding in areas that had problems with flooding earlier this week. The National Weather Service in Huntsville has places us under a Flash Flood Watch tonight and early Satuday. There will also be the threat for severe weather with some of the stronger storms.
A snapshot of 2:00am Saturday.

This is more raw data from Pinpoint Predictor that shows where the atmosphere will be the most unstable around 2:00am. This is represented as the area in blue. Although the most unstable air will be over NW Alabama the all of the storms will be able to feed off of this due to the south wind ahead of this line.

As the front continues to track east and southeast the threat for flash flooding will peak around 4:00am. 1-2" of rain could occur between 2:00am and 5:00am.

By 7:00am the rain will begin to taper off and temperatures will be on the way down for the rest of the day.

Below is the overall threat for this event. The main threat is flash flooding in yellow but the stronger storms could become severe and produce large hail and damaging winds. There is also going to be just enough spin in the atmosphere for tornadoes so we will be keeping a close eye on Live Storm Tracker Doppler throughout the night. Due to this shear the National Weather Service could place parts of North Alabama and southern Tennessee under a Tornado Watch at some point tonight. It would be a good idea to have your NOAA weather alert radio on tonight. We will be tracking the storms for you online at waff.com.

Projected rainfall totals between 12am and 8am Saturday morning. The areas of concentrated rainfall totals 1-2" will depend on where this line actually develops.

You can find more information on how to program your weather radio online at waff.com.
http://www.waff.com/story/5218974/how-to-program-your-midland-all-hazards-weather-radio
You can also keep up with the latest with our weather app.
http://www.waff.com/story/14059428/wafflaunches-android-weather-app
Brad Travis
Chief Meteorologist
WAFF 48 Storm Team
We Track Storms