Tn Valley Severe Weather

[jaxjagman]

Pretty boring severe season for us.Looks like it could get unsettled starting this weekend but other than that right now looks blah.CFS does have a Kelvin Wave moving through next  week with troughs coming through East Asia along with the MJO could actually strenghten into the IO.Could see a bigger deal around next weekend

[nrgjeff]

Wednesday afternoon the SPC updated Day 2 (for Thursday) pushing Slight into Nashville and adding 5% tornado from West Kentucky through Clarksville TN into the Nashville metro. 

That is along the Wednesday cool front, retreating as warm front and/or outflow boundary Thursday. See if any morning rain, which would actually enhance local SRH if rain departs by Noon.

I'm not really expecting anything big. Just need to give our region some attention. I can't get to the Plains yet, ha. Most likely Thursday Tenn / KY is just clusters and straight wind.

[Runman292]

3 hours ago, nrgjeff said:

Wednesday afternoon the SPC updated Day 2 (for Thursday) pushing Slight into Nashville and adding 5% tornado from West Kentucky through Clarksville TN into the Nashville metro. 

That is along the Wednesday cool front, retreating as warm front and/or outflow boundary Thursday. See if any morning rain, which would actually enhance local SRH if rain departs by Noon.

I'm not really expecting anything big. Just need to give our region some attention. I can't get to the Plains yet, ha. Most likely Thursday Tenn / KY is just clusters and straight wind.

What are your thoughts on Friday?

[PowellVolz]

What are your thoughts on Friday?

ETn will need the warm front to get out of the way earlier in the morning and take the elevated convection with it. Will be interesting to see what happens if it does clear out during the day.


.

[PowellVolz]

Tomorrow is looking interesting for ETn….

SPC…

Eastern KY and TN...
Early day storms may produce hail across the eastern half of TN and KY as large-scale lift and instability increase. The main threat is expected to be during the afternoon, ahead of the strong vorticity maximum, where clearing/heating takes place and shear is strong. While models vary regarding how much instability will develop, this area will be very favorable for an arcing line of low-topped supercells, with hail and tornado risk. An upgrade in risk category may be considered in later outlooks


.

[PowellVolz]

MRX…


Later in the morning, a second round of showers and thunderstorms
is expected to develop that could pose a severe threat to the
area. This activity is shown by the hi-res models to initiate
across N AL and the eastern portions of Middle TN around 12-14Z,
then intensify as it moves east. Increasing MLCAPE through the
day peaks around 1500 J/kg around 18Z, along with 0-3km SRH
values of 400-500 and 0-1km SRH around 200. This will be
conducive to supercells, as shown by the updraft helicity product
of the HREF, and with LCL heights under 1000m, a tornado threat
will be possible. A greater threat is expected from large hail, as
midlevel lapse rates will be steepening and the WBZ height
falling through the afternoon as the upper low approaches. Some
midlevel dry air and surface to midlevel theta-E difference of
25-30 deg C suggests a damaging wind threat as well. Bottom line,
we expect an active severe weather day tomorrow, mainly between
the hours of 10 AM and 6 PM. Some uncertainties with this severe
potential are how the early morning precip may limit
destabilization later in the morning, and if convective
development in GA will have an upstream stabilizing effect and
suppress the northward spread of low level moisture.


.

[PowellVolz]

Very surprised this cell SE of Memphis isn’t Tor warned.




.

[Runman292]

10 AM update from MRX:

An active severe weather day is expected. The main driver of this
event will be a negatively-tilted trough with a strong vort max
that will be rotating around a closed upper low, and the
associated jet streak at the base of that trough. Over the next
few hours, we expect that convection will develop along and west
of I-75, where the RAP and HRRR show an axis of higher CAPE
values. We are already starting to see this development in NE AL
at the moment. This instability axis shifts east into the central
Valley during the early afternoon, and into NE TN/SW VA in the
late afternoon. Aloft, we will have a surge of dry and cooler air
aloft that will aid in destabilization by steepening midlevel
lapse rates. In the 12Z OHX sounding, we are seeing values of 7.5
C/km, which will be advecting east. Deep shear will be adequate
for supercells, and 0-1 km shear values and LCL heights suggest a
tornado threat, mainly for areas south of I-40 and east of I-75.
However, it is notable that the HREF shows some updraft helicity
tracks north of I-40 this afternoon, so a tornado threat can`t be
ruled out anywhere.

This initial round of storms between 11-4 pm are expected to
mainly pose a damaging wind threat with a lower threat of
tornadoes, then a second round is expected to develop in the mid
to late afternoon near the Plateau, which may be primarily a hail
threat as WBZ heights quickly drop as the closed upper low
approaches. The HRRR shows this second round crossing our area
between 4-8 pm.

[1234snow]

Eastern Kentucky has been getting slammed all morning with heavy rain

[Dsty2001]

Been cloudy here all morning and now rain, wonder if that will limit the severe wx later today

[Runman292]

I wonder if all of this lingering rain is going to limit the overall severe threat this afternoon.

Edit: Dsty beat me to the punch, lol.

[Runman292]

As i just made my post, it looks like the sun is trying to come out in Oak Ridge.

[Dsty2001]

I know not all severe weather is directly related to daytime heating, I experienced one of the worst storms during a day that had rain on top of rain, however my knowledge is super lacking in this area.

[nrgjeff]

Good point Dusty. Actually the morning (or just earlier) rain likely laid down an outflow boundary which enhanced local storm relative shear SRH. Absolute instability is not always as important as the rate of destabilization - which is fast going from rain back to sun. Speaking of all that, East Tennessee had morning rain today (Friday May 6).

Surface low in IL about to track into IN. Cold front in Missouri is not drawn. Quasi dry line DL in yellow, hailers probably on it under colder mid-levels. Warm front WF in red should host some hailers with some wind. Prefrontal trough dotted green is most interesting. Should have a blend of instability and some wind shear.

Low level shear is a little better on the WF, but instability is just-in-time. DL is a little veered off both sides for tor. Prefrontal trough PFT might have that low top arc. We'll see. PFT could also accelerate (actually mix east faster with background wind) and/or merge with WF. Faster would put the area of interest east of Chattanooga later. Knoxville depends on instability and storm interaction.

Just in 16:30 SPC shows that arc shape with the ENH part. Flexible forecast for either WF or trough East Tenn. Arc into Georgia.

[PowellVolz]

Sun came out in Knoxville and you could definitely feel the change


.

[Runman292]

17 minutes ago, nrgjeff said:

Good point Dusty. Actually the morning (or just earlier) rain likely laid down an outflow boundary which enhanced local storm relative shear SRH. Absolute instability is not always as important as the rate of destabilization - which is fast going from rain back to sun. Speaking of all that, East Tennessee had morning rain today (Friday May 6).

Surface low in IL about to track into IN. Cold front in Missouri is not drawn. Quasi dry line DL in yellow, hailers probably on it under colder mid-levels. Warm front WF in red should host some hailers with some wind. Prefrontal trough dotted green is most interesting. Should have a blend of instability and some wind shear.

Low level shear is a little better on the WF, but instability is just-in-time. DL is a little veered off both sides for tor. Prefrontal trough PFT might have that low top arc. We'll see. PFT could also accelerate (actually mix east faster with background wind) and/or merge with WF. Faster would put the area of interest east of Chattanooga later. Knoxville depends on instability and storm interaction.

Just in 16:30 SPC shows that arc shape with the ENH part. Flexible forecast for either WF or trough East Tenn. Arc into Georgia.

This post is an example of why i love being on this board. I learn more about the weather than i ever would anywhere else.

[Runman292]

22 minutes ago, nrgjeff said:

Good point Dusty. Actually the morning (or just earlier) rain likely laid down an outflow boundary which enhanced local storm relative shear SRH. Absolute instability is not always as important as the rate of destabilization - which is fast going from rain back to sun. Speaking of all that, East Tennessee had morning rain today (Friday May 6).

Surface low in IL about to track into IN. Cold front in Missouri is not drawn. Quasi dry line DL in yellow, hailers probably on it under colder mid-levels. Warm front WF in red should host some hailers with some wind. Prefrontal trough dotted green is most interesting. Should have a blend of instability and some wind shear.

Low level shear is a little better on the WF, but instability is just-in-time. DL is a little veered off both sides for tor. Prefrontal trough PFT might have that low top arc. We'll see. PFT could also accelerate (actually mix east faster with background wind) and/or merge with WF. Faster would put the area of interest east of Chattanooga later. Knoxville depends on instability and storm interaction.

Just in 16:30 SPC shows that arc shape with the ENH part. Flexible forecast for either WF or trough East Tenn. Arc into Georgia.

I have a question. Will the storms down in Florida and Georgia have any notable impacts on the storms that form up here?

[John1122]

First tornado warning for Bell Co Kentucky. Radar indicated. That area has been prone to tornadoes in the past.

[Runman292]

Wow, it just went from a thunderstorm moving through to the sun being fully out and clouds disappearing in Oak Ridge. 

[Dsty2001]

Tornado Watch

TORNADO WATCH OUTLINE UPDATE FOR WT 186
NWS STORM PREDICTION CENTER NORMAN OK
140 PM EDT FRI MAY 6 2022

TORNADO WATCH 186 IS IN EFFECT UNTIL 800 PM EDT FOR THE
 FOLLOWING LOCATIONS

TNC001-007-009-011-013-019-025-029-035-049-057-059-063-065-067-
073-089-091-093-105-107-121-123-129-137-139-143-145-151-155-163-
171-173-179-070000-
/O.NEW.KWNS.TO.A.0186.220506T1740Z-220507T0000Z/

TN
.    TENNESSEE COUNTIES INCLUDED ARE

ANDERSON             BLEDSOE             BLOUNT
BRADLEY              CAMPBELL            CARTER
CLAIBORNE            COCKE               CUMBERLAND
FENTRESS             GRAINGER            GREENE
HAMBLEN              HAMILTON            HANCOCK
HAWKINS              JEFFERSON           JOHNSON
KNOX                 LOUDON              MCMINN
MEIGS                MONROE              MORGAN
PICKETT              POLK                RHEA
ROANE                SCOTT               SEVIER
SULLIVAN             UNICOI              UNION
WASHINGTON
$$

[Dsty2001]

Can't remember the last time a tornado watch dropped for the entire area

[Runman292]

It looks like there is a spin on the radar in middle tn. Is that the center of low pressure?

[John1122]

Had a pretty strong storm roll by a bit ago and it's thundering quite frequently now with a major downpour. That heavy rain has been the main story here. Between last night and today, I've gotten 3.4 inches and it's adding on fast. 

[Dsty2001]

Having a really intense storm roll through, started off with some hail then absolute down pour, pretty intense winds as well.  Power flickering, won't be surprised if we lose power

[PowellVolz]

Airport just gusted to 64




.

[Knoxtron]

 

[PowellVolz]

.

[Dsty2001]

2 minutes ago, PowellVolz said:

 

 

Ohhh that should put it on track to hit me if it holds together!

.

 

 

Ohh

[Dsty2001]

This last one that came through was something else, pretty sure I recorded some rotation but gonna have to check the video out to be sure.  Might have been scuds though

[John1122]

Had an epic rainer with pea sized hail and probably 40mph winds around 4:30.  Caused quite a few extra flooding issues. Well over 4 inches in the last 18 hours now.