Warm & Stormy Weekend

Tonight – Drying Out – Low 50s/Upper 40s

Water vapor imagery shows dry air spilling back into middle Tennessee. Looks dry tonight for all you JT and H.S. Football fans.

Friday night’s temperatures will be the coolest we get all weekend.

Saturday – Warm & Windy – Morning Low 48, Afternoon High 70

A strong south wind will be blowing at 15 mph. We aren’t expecting rain.

Sunday – Severe Weather Possible – Morning Low 60, Afternoon High 72

From our NWS office in Nashville (in blue):

At this time, will are still looking at the possibility of a fast-moving line of thunderstorms moving through middle Tennessee Sunday evening.  The squall line should start to move into middle Tennessee in the 4 pm – 6 pm time frame Sunday and exit into eastern Tennessee shortly after midnight.

Along the squall line, there will be the potential for isolated strong damaging winds, and though a tornado or two can’t be ruled out, the strong winds will likely be the main threat.  

The current graphic from the Storm Prediction Center (below) is unchanged from this morning:

The SPC will update this graphic around 1230 a.m. tonight (then again shortly after noon on Saturday).

This afternoon’s Forecast Discussion unpacks some of the uncertainty:

“Confidence still isn’t great on what we can expect” Sunday. “We will definitely see some rain and some thunderstorms…but it’s mode of convection that is greatly in question.” Meaning, something’s going to happen Sunday, but we aren’t exactly sure what.

Sunday’s storm system will have more instability, but less shear, than the Halloween storm system. This combination could result in a more storm-friendly environment than we saw on Halloween.

Two main variables are in play:

  1. It may rain Sunday morning, followed by a “dry air intrusion” Sunday afternoon, clearing us out. That would be great for those with Sunday afternoon plans, but it would cause more problems later. Sunday afternoon sunshine will heat us up and destabilize the atmosphere. The squall line would then arrive Sunday night, encounter the unstable air, and enhance the damaging straight-line wind threat. It would also be possible for tornadoes to spin up along the squall line.
  2. Storms will also develop in Alabama, and if they’re widespread enough, they may cut off our supply of warm, wet air from the Gulf needed to feed our storms.

Non-Thunderstorm Winds. You’ll notice sustained winds picking up Saturday (around 15 mph). By Sunday, winds will gust to 30 mph, and may necessitate a Wind Advisory.

Rain Totals. We expect around 0.6″ of rain Sunday.

Next Week – Dry & Not Supercold

Look for lows in the mid-30s, highs in the mid-to-upper 50s.

Much more on this tomorrow!

Questions? We’re on Twitter @NashSevereWx.