East Tennessee Weather II

[MetVol]

It's about to ramp up some more across southeast TN. Lots of spinners. Saw an updated sounding from UAH which showed the decreasing and much better surface backed flow for enhanced low-level rotation.

 

[Vol knight]

Update:

According to the SPC in their latest discussion, there will be a new tornado watch issued for most of East TN within the next hour.

 

[Vol knight]

Alert!!!!!

The National Weather Service in Morristown has issued a

* Severe Thunderstorm Warning for...
Northern Sequatchie County in east Tennessee...
Bledsoe County in east Tennessee...

* Until 715 PM CST.

* At 609 PM CST, severe thunderstorms were located along a line
extending from 6 miles east of Sparta to 8 miles south of Spencer
to near Decherd, moving northeast at 50 mph.

HAZARD...60 mph wind gusts and penny size hail.

SOURCE...Radar indicated.

IMPACT...Expect damage to roofs, siding, and trees.

* Locations impacted include...
Dunlap, Pikeville, Palio, Brayton, Melvine, Mount Crest, Old
Cumberland, Cagle and Fall Creek Falls State Park

 

[Vol knight]

Alert!!!!!

The National Weather Service in Morristown has issued a

* Severe Thunderstorm Warning for...
Southern Morgan County in east Tennessee...
Northern Rhea County in east Tennessee...
Northeastern Meigs County in east Tennessee...
Anderson County in east Tennessee...
Roane County in east Tennessee...

* Until 845 PM EST.

* At 747 PM EST, severe thunderstorms were located along a line
extending from Fairfield Glade to 8 miles north of Spring City to
14 miles south of Crossville to Pikeville, moving east at 50 mph.

HAZARD...60 mph wind gusts and penny size hail.

SOURCE...Radar indicated.

IMPACT...Expect damage to roofs, siding, and trees.

* Locations impacted include...
Oak Ridge, Clinton, Kingston, Rockwood, Wartburg, Fairview, Oliver
Springs, Spring City, Midtown and Harriman.

 

[norrislakevol]

It uses the NWS forecast and applies a statistical regression equation derived off of NBM and WPC ensembles.

Excellent. I am just getting accustomed to using the NBM.

 

[Matt2496]

tornado watch extended for most of East Tennessee

Storm Prediction Center Tornado Watch 7

 

[Vol knight]

Heads up!

There is broad rotation in parts of the line, so a brief tornado or 2 could occur.

 

[davethevol]

Heads up!

There is broad rotation in parts of the line, so a brief tornado or 2 could occur.

Is that basically the whole line then, or certain areas?

 

[Vol knight]

Is that basically the whole line then, or certain areas?

Certain areas, but it can occur in any part of the line.

Seeing a report of a few downed trees in Bledsoe county.

 

[Vol knight]

Heads up!!!!!!!!

Folks in and around Chattanooga need to watch the tornado warned storm just to the south. Unfortunately, i'm having to go through it coming back from vacation.

 

[Vol knight]

Alert!!!!!!!

The National Weather Service in Morristown has issued a

* Severe Thunderstorm Warning for...
Bradley County in east Tennessee...
Southeastern Marion County in east Tennessee...
Hamilton County in east Tennessee...

* Until 1045 PM EST/945 PM CST/.

* At 955 PM EST/855 PM CST/, a severe thunderstorm was located 7
miles southeast of Jasper, moving east at 55 mph.

HAZARD...60 mph wind gusts.

SOURCE...Radar indicated.

IMPACT...Expect damage to roofs, siding, and trees.

* Locations impacted include...
Chattanooga, Cleveland, Soddy-Daisy, Signal Mountain, Rossville,
Walden, Lakesite, Whitwell, Charleston and Ridgeside.

 

[Matt2496]

Heads up!!!!!!!!

Folks in and around Chattanooga need to watch the tornado warned storm just to the south. Unfortunately, i'm having to go through it coming back from vacation.

Hope you have a safe trip!

 

[Vol knight]

Update:

I'm anticipating that the Tornado watch will be cancelled within the next hour or so. The severe threat is winding down.

 

[MetVol]

Update:

I'm anticipating that the Tornado watch will be cancelled within the next hour or so. The severe threat is winding down.

Yeah I'd say Knoxville and most of the northern extent are removed from the watch very soon. Might keep some of the southern parts of TN in it a little longer with some weak instability near that area and some storms in N AL still tracking NE along that boundary. Overall severe risk is winding down for the night, though.

 

[norrislakevol]

Models have really strengthened the low pressure system that will give us some snow, hence the WWA and Winter storm warning, depending on where you live. The GFS really has it winding up in a small area. Check out the tight isobars. Will be interesting to see how heavy the precip gets. Dynamic cooling will likely be a factor for areas from Knoxville eastward.

http://mag.ncep.noaa.gov/data/gfs/0...precip/gfs_conus_025_850_temp_mslp_precip.gif

 

[headhunter15]

 

[yoyoyoyo]

Nashville NWS said:
If the snowier trend continues, amounts may need to be pumped up more. The track and strength of the closed upper low will be key.

 

[MetVol]

Nashville NWS said:
If the snowier trend continues, amounts may need to be pumped up more. The track and strength of the closed upper low will be key.

I'd agree. Trends have been to nudge the low westward and most guidance is in agreement now. That's really increased totals around East Tennessee. Upper low plus strong mid-level frontogenesis is going to be the focus for NW quadrant precip and snowfall. Along with some elevated conditional instability, we'll see opportunity for banding, heavy snow rates over a few hours, and perhaps some convection tall enough to get a bolt of lightning or two. With the gradient tightening, good chance of seeing blizzard conditions across the higher elevations of the mountains late tonight.

Updated HRRR 12z which accounts for melting:

 

[rocktopper16]

 

[headhunter15]

Good news?

 

[headhunter15]

NWS with an update. Increased totals.

 

[hUTch2002]

NWS with an update. Increased totals.

They just moved Knoxville into the Winter Storm Warning and bumped the expectation up to 2-4 inches.

 

[Matt2496]

Even Huntsville is now under a WSW

 

[norrislakevol]

According to the GFS and the RAP models it looks like a general 2 to 4 inches state wide with the exception of extreme western Tennessee and Extreme Southern valley where there will be less, and the Smokeys areas near the Smokeys, where there will be higher amounts. The NAM is still out to lunch. It isn't handling this well at all. The HREF indicates that everyone in Tennessee East of Nashville has a 90 plus percent chance of seeing at least 1 inch within a 3 hour period. We will just have to see how heavy this gets and how cold it gets for the southern valley. Everyone else should see 2 inches plus on at least grassy and elevated surfaces, with heavier bursts there will be at least some travel problems for some, plus the wind will cool road surfaces quicker in some areas.

 

[MetVol]

Even Huntsville is now under a WSW

Their criteria for a WSW is a little lower, but I could definitely see some 1-2" accumulations around HUN with locally higher amounts; definitely along the ridgetops around there. The WSW criteria changed for MRX this year from 4" to 3" along the southern and central valley.

Here's the most recent HRRR snow depth. Tons of dynamics with this system. Strong 700mb frontogenesis and some instability above that layer to take advantage of the strong omega. Going to get some convective banding and expect a pretty strong gradient in snow totals near Knoxville. East of Knoxville totals are going to increase quickly with much lower totals west of Knoxville. Highest totals along the foothills and into the mountains. With the convective banding, might actually get some thunder snow east of Knoxville. It's not often that we have strong enough dynamics to support that around here.