Overnight storm threat update - WAFF-TV: News, Weather and Sports for Huntsville, AL

The latest outlook from the Storm Prediction Center out this morning now places parts of western Alabama in a Slight Risk for the potential for some damaging winds as a weakening line of storms moves in after 10 p.m.  

Meteorologist Jeff Castle is monitoring the latest this morning and will have updates on WAFF throughout the morning and another look at weather on WAFF 48 News at Noon.

Initially this afternoon and early this evening there will be a tornado threat for areas to our west including Arkansas, NE Louisiana, SW Tennessee and SE Missouri. This threat is based on the forecast for isolated supercell storms in the early evening hours.

There will be a short window of opportunity for these supercell storms to develop west of our area. As we get later into the evening hours a line of storms will form and quickly move to the east. Moving into Alabama after 10 p.m. At that time the greatest threat will likely come from straight line winds.

The area of greatest low level instability will be around 11 p.m. It is well west of us. This is why the storms  will be weakening once they get into eastern Mississippi. When you have an organized line of convection moving into a stable airmass you can get what is called a Gravity Wave. This happens because the storms build up a lot of momentum and then collapse once they encounter the stable air. This can lead to a widespread area of 35 to 45 mile per hour winds. This is one thing we will be watching that could happen as this line move in overnight tonight.  

There still remains the possibility of some isolated, severe, wind gusts in west Alabama as this line moves in. Severe wind gusts are defined by the National Weather Service as winds at least 58 miles per hour.  Stay tuned for further updates on this developing change in the weather.

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