Tn Valley Severe Weather

[nrgjeff]

The 2% on Monday verified in Tennessee, but most of the tweets are scrubbed. Also possible she blocked me for political reasons. Layperson not media.

Today we have 0% strong in North Bama. Very subtle boundary is trying to lift north. Outflow from Mid-South is oriented NE to SW; and, they may intersect later. However the LLJ is modest to meager. CAMs fire it, but it could just be blobs. SPC coveres farther north.

Wednesday is the classic outflow boundary day. Models verbatim have it lifting into Kentucky, which looks reasonable with strong enough WAA. If greater precip coverage in the morning, the boundary could get stuck in Tenn. Right now only the Euro has that.

[Matthew70]

Uh No!

[Matthew70]

Also STPs are just about maxed from KY line to I40 tomorrow. 

[Runman292]

Just about everyone in TN is now in the Enhanced risk for Severe storms tomorrow.

[nrgjeff]

Warm front is going to light up, and perhaps with supercells. It will start the day draped straight across Tennessee. You want daytime in the east?

ECMWF and a couple high-res hang it up in Tennessee, which would be bad news. Most everything else lifts it into Kentucky before it goes berserk.

Then of course overnight Wednesday night a huge red bow squall line is forecast to rake the state. Two rounds. We wouldn't do it any differently in the South!

[Runman292]

3 minutes ago, nrgjeff said:

Warm front is going to light up, and perhaps with supercells. It will start the day draped straight across Tennessee. You want daytime in the east?

ECMWF and a couple high-res hang it up in Tennessee, which would be bad news. Most everything else lifts it into Kentucky before it goes berserk.

Then of course overnight Wednesday night a huge red bow squall line is forecast to rake the state. Two rounds. We wouldn't do it any differently in the South!

What would the warm front staying in TN cause?

[Matthew70]

Where the warm front is, there will probably be training super cells. The warm front also acts as a lifting mechanism. It also puts you closer to the triple point.  

[John1122]

I expect a nearby plateau tornado at this point. Seem to get several a year that get close these days. 

[jaxjagman]

Smith Co tornado yesterday was a confirmed EF-1

[Matthew70]

this is why we don’t want the warm front near us.

From the latest SPC MD:

"No less than half a dozen long-lived supercells are
currently noted near this warm front, several of which are, or have
been tornadic. "

 

[Runman292]

17 minutes ago, Matthew70 said:

this is why we don’t want the warm front near us.

From the latest SPC MD:

"No less than half a dozen long-lived supercells are
currently noted near this warm front, several of which are, or have
been tornadic. "

 

How can I view the placement of the warm front on models?

[Carvers Gap]

I am not liking this.

[Matthew70]

4 minutes ago, Carvers Gap said:

I am not liking this.

Nope.  This is looking like an April type dat.  Go the whole month of April wo severe wx & tornadoes & May says “April Fools”! 

[yoda]

5 hours ago, Carvers Gap said:

I am not liking this.

45% hatched wind and hail on new Day 1

[Runman292]

50 minutes ago, yoda said:

45% hatched wind and hail on new Day 1

30% hatched hail goes all the way east into Knoxville.

[Runman292]

Latest AFD from MRX:

.SHORT TERM...

(Today and tonight)

Issued at 341 AM EDT Wed May 8 2024

 

Key Messages:

 

1. A regional severe weather outbreak is increasingly likely from late this afternoon through tonight across the Mississippi River Valley and Tennessee Valley.The threats include widespread damaging winds, very large hail, and tornadoes (including EF-2+ strength). The tornado threat is highest along and west of Interstate 75.

 

2. Scattered to possibly numerous instances of flooding are likely, especially west of Interstate 75. This threat will be most amplified from this evening to Thursday morning.

 

Today and Tonight

 

Currently early this morning, a 120+ kt 250mb jet extends into the western Great Lakes with a southern jet of near 100 kts extending from the southern Mississippi Valley. A very broad warm sector is also in place with a cold front near the Mississippi River and a warm front near the Great Lakes. Also, strong to severe convection is ongoing across the Ohio River Valley and will continue to progress southward through the morning hours. By daybreak, the aforementioned northern jet will progress towards the eastern Great Lakes with the left-exit region of the southern jet being placed directly over Tennessee and westward. This will create a strongly divergent pattern aloft. The timing of when this initial convection arrives is still somewhat uncertain, but a later timing (early afternoon) would allow for more destabilization beforehand and could slightly limit instability for the evening/overnight period. In any case, deep-layer shear by the early afternoon will reach near or above 40 kts with MLCAPE in excess of 2,000 J/kg. During this time, the flow pattern will still be fairly light and still somewhat uni-directional, but the thermodynamics and overall profiles are still sufficient for storm organization and a damaging wind and hail threat.

 

By the late afternoon through tonight, the wind profile will strengthen and become increasingly more veered with opportunity for additional destabilization beyond 2,500 J/kg of MLCAPE, especially if there is some break in earlier activity. During this timeframe, effective shear is expected to reach or exceed 50 kts with very right-turning hodographs. The CAMs still differ some on the timing and evolution of convection, but most solutions suggest widespread organized supercells by the late afternoon along and north of Interstate 40 with one or more line segments arriving through the evening hours. While the low-level shear isn`t too strong, impressive low-level instability and veering wind direction yield pretty high confidence in STP values to exceed 2 or 3, especially along and west of Interstate 75. In the mid-levels, lapse rates of around 7 Celsius/km or greater can be expected with very impressive CAPE in the -10 to -30 Celsius region of 800 to 1,000 J/kg. While the CAMs differ on exact timing and storm mode, widespread storms are indicated anytime from the afternoon through the overnight hours, initially focused north and then shifting south. The latest HREF data suggest a broad swath of updraft helicity tracks across much of the area and focused especially along and west of Interstate 75. In any case, it should be noted that this system has already produced numerous tornadoes, including some strong to violent, across the Great Plains to places along and north of the Ohio River Valley. This event will also almost certainly continue to the overnight hours, presenting a nocturnal severe weather threat.

 

Another important aspect of this event is duration, intensity, and coverage of convection. Places further south may not see as much coverage during the day, but this will likely occur more from the evening to early Thurday morning. The CAMs are indicating high probabilities for over 3" of rainfall with notable probabilities (20 to 30 percent) for 5" or more of rainfall. Just as with the tornado threat, this is elevated even more further west. Based on the strong signals and likelihood of significant rainfall, a Flood Watch wasissued for the entire area. The threat is certainly not uniform area-wide, but the signals suggest rainfall and antecedent conditions sufficient for scattered to maybe even numerous instances of flooding.

 

[1234snow]

First tornado warning of the day for Clay, Jackson and Overton counties.

[1234snow]

Tornado warned cell heading toward Morristown.

[Runman292]

Will these morning storms weaken the storms later on?

[Stovepipe]

That was a helluva frog strangler in Knox county.  Fortunately no hail here that round.

[KnoxLC]

6 minutes ago, Stovepipe said:

That was a helluva frog strangler in Knox county.  Fortunately no hail here that round.

It missed us in Farragut, but it still looks ominous.

 

[nrgjeff]

Before 11am @John1122 verifies. Photo Greg Williams a HAM / spotter in Crosville. May 8

Anywhere else I'd question it. On the Plateau, that's probably what it looks like. 

[jaxjagman]

HRRR has been showing a stronger cap compared to the RAP,dunno who is gonna be right

 

National Weather Service Nashville TN
914 AM CDT Wed May 8 2024

...New MESOSCALE UPDATE...

.MESOSCALE UPDATE...
Issued at 856 AM CDT Wed May 8 2024

Warm front has become stationary close to I-40. Showers with very
heavy rainfall and thunderstorms continue to move eastward along
and just north of the boundary. Very heavy rainfall continues to
feed the flood threat across our far north.

To the south, the southern half of the mid state will receive a
break with some capping now noted into the early afternoon.
However, SPC parameters indicate additional destabilization as the
day wears on. Primary push of pre frontal initial energy appears
to be mid to late afternoon. At that time...cape values of up to
4000 j/kg will be in place across our south with MLLR`s of 7C to 7
1/2C. Some clearing is already noted in our southwest....not
good. 0-1km Helicity values will be in the 100-200 M(2) S(-2)
range. Severe out break round 1 will likely occur across the
central and south as we move into the mid to late afternoon. All
forms of severe weather will be possible.

Activity now firing across central Mo. This will represent the
energy later in association with the primary frontal boundary.
This round 2 activity looks like sometime between 6 PM and
midnight for all of the mid state. Again, all forms of severe
weather will be possible.

[Matthew70]

Well if there was ever a loaded gun for middle TN south of I40.  Today is that day.  Ugh. 

[Matthew70]

1 minute ago, jaxjagman said:

HRRR has been showing a stronger cap compared to the RAP,dunno who is gonna be right

 

National Weather Service Nashville TN
914 AM CDT Wed May 8 2024

...New MESOSCALE UPDATE...

.MESOSCALE UPDATE...
Issued at 856 AM CDT Wed May 8 2024

Warm front has become stationary close to I-40. Showers with very
heavy rainfall and thunderstorms continue to move eastward along
and just north of the boundary. Very heavy rainfall continues to
feed the flood threat across our far north.

To the south, the southern half of the mid state will receive a
break with some capping now noted into the early afternoon.
However, SPC parameters indicate additional destabilization as the
day wears on. Primary push of pre frontal initial energy appears
to be mid to late afternoon. At that time...cape values of up to
4000 j/kg will be in place across our south with MLLR`s of 7C to 7
1/2C. Some clearing is already noted in our southwest....not
good. 0-1km Helicity values will be in the 100-200 M(2) S(-2)
range. Severe out break round 1 will likely occur across the
central and south as we move into the mid to late afternoon. All
forms of severe weather will be possible.

Activity now firing across central Mo. This will represent the
energy later in association with the primary frontal boundary.
This round 2 activity looks like sometime between 6 PM and
midnight for all of the mid state. Again, all forms of severe
weather will be possible.

From what I’ve seen the HRRR has not performed well last few days.  

[nrgjeff]

WBIR viewer Rutledge, Tenn. I believe this morning. While it has a scuddy look, I lean TOR. It's all by itself. I infer inflow from our right. It's in the correct part of the storm base. 

Quick note about Southern Tenn. Outflow has clearly detached from the warm front. RRFS picks up on southern Tennessee storms later. 

[Carvers Gap]

That t-storm complex damaged a school in Hamblin according to the Times-Tribune.  NO injuries were reported though some students have had to be relocated as they assess damage.

https://www.citizentribune.com/news/update-severe-weather-blasts-through-morristown-surrounding-areas/article_29233634-0d50-11ef-b9bd-87889de4b563.html

East side of Cherokee Lake did experience golfball to baseball size hail.

[Carvers Gap]

NWS-MRX is posting some photos now of the Morristown damage.  Looks like 2-4" wind driven hail.  And let me tell you from experience(not this year knock on wood), that sucks.  

[Carvers Gap]

I spoke with our catastrophic storm assessor (he was working my roof several years back)...he said he handled an EF-4 or 5 maybe in Indiana or Illinois years back.  He said softball sized hail had been driven through the side of cars and into the side of the engine block(dents were evidence).   State Farm covered 25-30K in damages for us (July 27, 2014) due to baseball and softball size hail.  It wasn't wind driven, but it knocked holes in my gutters and lawn furniture.  Hundreds of dents in our truck and van along w/ broken windows.  It sounded like bricks falling on the house.  Our chimney vent still have dents in them.  It was the worst sound I have ever heard.  You could hear the damage in the neighborhood as it fell.  My sister's house lost their vinyl siding(due to hail) in that storm or the one a few year prior.  

So, heart felt condolences to the folks in the area where the large hail hit.  

[KnoxLC]

7 minutes ago, Carvers Gap said:

I spoke with our catastrophic storm assessor (he was working my roof several years back)...he said he handled an EF-4 or 5 maybe in Indiana or Illinois years back.  He said softball sized hail had been driven through the side of cars and into the side of the engine block(dents were evidence).   State Farm covered 25-30K in damages for us (July 27, 2014) due to baseball and softball size hail.  It wasn't wind driven, but it knocked holes in my gutters and lawn furniture.  Hundreds of dents in our truck and van along w/ broken windows.  It sounded like bricks falling on the house.  Our chimney vent still have dents in them.  It was the worst sound I have ever heard.  You could hear the damage in the neighborhood as it fell.  My sister's house lost their vinyl siding(due to hail) in that storm or the one a few year prior.  

So, heart felt condolences to the folks in the are where the large hail hit.  

This could end up being another April 2011 as far as insurance claims go...so much hail damage then that I think insurance companies paid to re-roof most of their customers' homes in the Knoxville area. Plus straight-line winds. I had a tree fall through our roof in the front yard and a wooden privacy fence blown over in the back yard. A tree at the corner of the backyard (on my neighbor's property was uprooted and laid down on the ground -- the trunk was so wide on it that two people couldn't have touched hands around the trunk. Powerful storms.

What are the chances that the severe threat is over now that we've had this round of storms?