Tn Valley Severe Weather

[Holston_River_Rambler]

I'll create a thread for it. You can actually see the wind shear on the OHX radar this morning. Not something I think I've ever seen before in out area. Not saying that's never happened, just I haven't noticed it. 

[PowellVolz]

Thought I would drop this off here. It’s a “season preview” and prediction from a YouTube Met that I personally believe does an excellent job on his site. The cliff notes are he looked and came up with his analogs that closely match the pattern we are in, or going into to. These are his analog years…. Closest years to this year are 1976 and 2002. Next is 2018 and 2009 and last is 2012 and 1965. All of these years except for 1965 basically played out the same. A very active end of March into April for Dixie and then everything moved more towards tornado alley for May into June. All of these years had well above average tornadoes but these years did not have many significant tornadoes except for 1965. 1965 was a weird analog year because it lined up well with our setup and predicted pattern going forward but it was overly active with several significant tornado outbreaks and several significant tornadoes. Oddly enough that MTn and ETn was very active in 1965. Here’s the video, it’s about an hour long.

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[Matthew70]

On 3/8/2023 at 7:47 AM, PowellVolz said:

Thought I would drop this off here. It’s a “season preview” and prediction from a YouTube Met that I personally believe does an excellent job on his site. The cliff notes are he looked and came up with his analogs that closely match the pattern we are in, or going into to. These are his analog years…. Closest years to this year are 1976 and 2002. Next is 2018 and 2009 and last is 2012 and 1965. All of these years except for 1965 basically played out the same. A very active end of March into April for Dixie and then everything moved more towards tornado alley for May into June. All of these years had well above average tornadoes but these years did not have many significant tornadoes except for 1965. 1965 was a weird analog year because it lined up well with our setup and predicted pattern going forward but it was overly active with several significant tornado outbreaks and several significant tornadoes. Oddly enough that MTn and ETn was very active in 1965. Here’s the video, it’s about an hour long.
 

 

 

 

 

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It will be interesting how spring plays out.  To me it seems we are in a cooling trend the last few years. Though data says we’re warming to me it seems to be going the opposite. I believe severe wx will be very quiet again this spring. I just believe springs are just getting cooler.  I could be totally wrong & hope that I’m not because I don’t care for tornadoes.  

[jaxjagman]

On 3/8/2023 at 7:47 AM, PowellVolz said:

Thought I would drop this off here. It’s a “season preview” and prediction from a YouTube Met that I personally believe does an excellent job on his site. The cliff notes are he looked and came up with his analogs that closely match the pattern we are in, or going into to. These are his analog years…. Closest years to this year are 1976 and 2002. Next is 2018 and 2009 and last is 2012 and 1965. All of these years except for 1965 basically played out the same. A very active end of March into April for Dixie and then everything moved more towards tornado alley for May into June. All of these years had well above average tornadoes but these years did not have many significant tornadoes except for 1965. 1965 was a weird analog year because it lined up well with our setup and predicted pattern going forward but it was overly active with several significant tornado outbreaks and several significant tornadoes. Oddly enough that MTn and ETn was very active in 1965. Here’s the video, it’s about an hour long.
 

 

 

 

 

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Tried to like it but it wouldnt let me for some reason.March is gonna have a rough go with that MJO signal,looks like winter will arrive when no one wanted it no more,least i dont.

[jaxjagman]

This pattern seems to warm Into the Yellow Sea and Sea of Japan like the vid shows and even into the Bering Sea

Into East Asia there has been nothing but Ridges in this area since December and the SST's are around 1.5-1.8C above normal.If these warm SSTS hold on you could see a  potential  decent Baiu front into Japan into summer along with some potential strong phoons.

[jaxjagman]

Seems like the models are fairly close today.Upper level ridge building to our east next Friday could bring a decent CF around next Friday.But already seeing signs of the blah cap,see what it looks like in a couple days

[jaxjagman]

Still think its possible those warm SST'S ARE LIKE 2018 in East Asia,but we'll see.To many similarities right now,.2018 wasnt the worse in the mainland for tornadoes,but there was no EF4 OR EF5 that year

This map shows the tracks of all tropical cyclones in the 2018 Pacific typhoon season. The points show the location of each storm at 6-hour intervals. The colour represents the storm's maximum sustained wind speeds as classified in the Saffir-Simpson Hurricane Scale (see below), and the shape of the data points represent the type of the storm. 

[jaxjagman]

 Day 4-8 Convective Outlook  
   NWS Storm Prediction Center Norman OK
   0405 AM CDT Sun Mar 19 2023

   Valid 221200Z - 271200Z

   ...DISCUSSION...
   Airmass modification and a northward flux of low-level moisture will
   occur across the southern Plains through mid-week, as upper trough
   amplification occurs over the Southwest. On Day 4/Wednesday, while a
   15+ percent severe area is not currently warranted, some severe
   potential may exist near a surface low across Kansas and a front
   extending east-northeastward into Missouri/Illinois. 

   For Day 5/Thursday, severe weather seems probable across portions of
   the southern Plains Thursday afternoon and Thursday night. Current
   thinking is that severe potential should be maximized near the
   advancing cold front across Oklahoma toward the Ozarks and near the
   southward-extending dryline into north/west-central Texas. All
   severe hazards are plausible.

   Severe-weather potential will likely persist eastward toward the
   ArkLaMiss/Lower Mississippi Valley and Tennessee into Day/6 Friday.
   This scenario will be supported by strong deep-layer/low-level
   winds, atop a relatively moist boundary layer ahead of a cold front
   and/or lingering convection from Day 5/Thursday night.

   Thereafter, guidance variability considerably increases into the
   weekend, with uncertainties regarding the details of subsequent
   severe potential.

   ..Guyer.. 03/19/2023

[nrgjeff]

Outflow boundary OFB re-lifting now through the Mid-South is going to be trouble.

Initial line coming into Memphis might not have the moisture yet. Dry pocket aloft Mississippi means the best 850 mb moisture has to sneak up the Delta. It should be there late afternoon, along with the SRH on that outflow boundary. Hopefully for MEM, the OFB is elsewhere later. It is lifting north but could stall or sink with the early afternoon precip.

OFB should also snake through Middle Tennessee later this evening. By then storms could be more QCLS than sups. Also have to watch the synoptic warm front if the air between the OFB and WF can warm up. Otherwise it's a big ol' Southern line overnight.

[Knoxtron]

Could be getting some insane flash flooding, potential for 1 in 100+ year short term event?

 

 

For Knoxville - NOAA 14 Pt Precipitation Frequency Estimate

[jaxjagman]

That was a good storm just passed through,my radar showed the dbz around 58 around my house,Hardest rain ive seen in years for a brief time,other than that..just blah,it was still exciting

[Matthew70]

38 minutes ago, jaxjagman said:

That was a good storm just passed through,my radar showed the dbz around 58 around my house,Hardest rain ive seen in years for a brief time,other than that..just blah,it was still exciting

Yeah rain & some good lighting at times.  Other than that just another quick moving storm.  I’m not going to complain.  Reports out of Armory, MS are horrific. I hate tornadoes.  Destroying homes & property & lives is all they are good for.  I hope for this area they continue to bust. 

[Jed33]

7 hours ago, Matthew70 said:

Yeah rain & some good lighting at times.  Other than that just another quick moving storm.  I’m not going to complain.  Reports out of Armory, MS are horrific. I hate tornadoes.  Destroying homes & property & lives is all they are good for.  I hope for this area they continue to bust. 

Oh man, Amory, MS is my hometown! I’ve just been talking to everyone I know. So far, everyone is safe, but one friend lost his house and the entire neighborhood. Apparently the north side of the town was destroyed. Just a terrible, terrible situation. My heart aches for those people! Just up the road is Smithville where the EF5 went through in 2011. That area has truly been hit hard over the past 12 years!

[nrgjeff]

A true Gulf Coast warm front lifted through Mississippi last night. Appears it intersected a couple pre-trough convergence lines. Due to the deep moisture with a Gulf WF instability remains overnight. 

Separately In the satellite chart on my Friday post, appears a couple dark lines in central Mississippi make a T. That could have been another subtle boundary intersection, but at the time a little dry air just off the surface kept it in check during the day.

The loss of life is tragic. Agree with Matthew that in the South significant tornado events are usually bad news.

Back here in Tennessee the lifting outflow boundary (well north of the Gulf boundary) tended to focus straight line winds. However some QLCS tornadoes were reported in North Alabama. Got sideways rain on straight line wind at 3am in Chattanooga.

0656  65  4 ESE CHATTANOOGA

HAMILTON TN  CHATTANOOGA ASOS RECORDED A 65 MPH WIND GUST. (MRX)

[jaxjagman]

The east warmed up fast,still looks to be a positve TNI but thats gonna fade away soon

[Daniel Boone]

19 minutes ago, jaxjagman said:

MJO is leaving the IO back into the COD  then seems to resurface back into the WP,this could mean a big hydro problem with April showers.This pattern seems eerie 2018 written all over it.Chance of some strong storms as we head into April then right now the Euro shows a better chance as we head towards the Mid month.The Euro in 8-9 days shows maybe a strong POTENTIAL strong ULL around North East China with a Upper level ridge towards the proximity of Northern Japan.This isnt a forecast,just my beliefs of the upcoming pattern that might evolve

 

 

 

https://www.etsu.edu/cas/geosciences/tn-climate/documents/2018_04.pdf

Yeah, looks pretty similar. 

[Matthew70]

5 hours ago, Daniel Boone said:

I’m in not liking the looks of possible severe wx including tornadoes.  Let’s just say none of that please! 

[PowellVolz]

Unfortunately it looks like weather is about to pick up in a bad way.

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[jaxjagman]

On 3/26/2023 at 5:07 PM, Daniel Boone said:

Yeah, looks pretty similar. 

I took that post off.i just noticed site hasnt updated in over a week

[Ed, snow and hurricane fan]

GFS has been too cool and instability has been too low last few severe outbreaks.  10F warmer, and with some CAPE at BNA Friday evening, this is spooky sounding.

[Matthew70]

2 hours ago, Ed, snow and hurricane fan said:

GFS has been too cool and instability has been too low last few severe outbreaks.  10F warmer, and with some CAPE at BNA Friday evening, this is spooky sounding.

It says potential hazards none?

[Ed, snow and hurricane fan]

4 minutes ago, Matthew70 said:

It says potential hazards none?

I added a qualifier about the GFS being too cool and too stable in recent outbreaks.  Shear/vorticity are enough with even moderate instability for a significant severe outbreak w/ tornadoes.  No potential hazards is based on the GFS forecast of no instability, which is probably wrong.

[Matthew70]

7 hours ago, Ed, snow and hurricane fan said:

I added a qualifier about the GFS being too cool and too stable in recent outbreaks.  Shear/vorticity are enough with even moderate instability for a significant severe outbreak w/ tornadoes.  No potential hazards is based on the GFS forecast of no instability, which is probably wrong.

Thank you for the input. 

[nrgjeff]

Either way the CAPE will probably be 'skinny' on the Nashville Skew-T overnight, without diurnal heat. Low level CAPE will depend on steady temps after the initial sunset drop.

General wind shear aloft is forecast overnight into Middle Tenn. As usual overnight shear can endure when CAPE fades. Still early to forecast low level shear and boundaries though.

Mid-South late Friday afternoon into early evening is a bigger concern. CAPE and shear will be juxtaposed. A prefrontal trough or convergence zone could be surface drivers. Such details are still TBD.

[Matthew70]

After what happened in MS I would prefer chilly air than tornadoes.  Though unfortunately it seems we are entering a severe timeframe which always seems to go hand & hand with around Easter.  TN has been fortunate these last few years.  Hopefully our luck has not run out.  Friday is yet to be determined exactly but appears most affected is west to middle.  Now the 4/4 system could have many more involved. Time to perk up & listen to the experts.  

[PowellVolz]

...Mid-South Vicinity...

A concerning scenario appears to be developing across portions of the MO Bootheel, northeast AR, western TN/KY and far northwest MS vicinity during the afternoon/evening. At least mid-60s F dewpoints are expected beneath modest midlevel lapse rates. This will support 1500-2000 J/kg MLCAPE amid intense vertical shear. Forecast soundings indicate 0-1 km SRH increasing to around 400 m2/s2 by early afternoon. Thunderstorms are expected to develop by early afternoon ahead of the cold front within a pre-frontal trough/low-level confluence zone. Storm motion near 50 kt with supercell wind profiles will support cells capable of significant and long-track tornadoes. With time, upscale growth into a QLCS is expected, and intense wind gusts will be possible in addition to mesovortex tornadoes.

...OH/TN Valley vicinity...

Low-level moisture/instability will begin to wane with north and east extent into the nighttime hours. However forecast guidance has consistently shown a few hundred J/kg MLCAPE with little/no inhibition. Forecast guidance generally tends to under-forecast north/east extent of severe potential in strongly forced, intense shear system. As such, the ongoing outlook maintains a broad gradient from Enhanced to Slight risk across this region. Damaging gusts and a few QLCS tornadoes will be possible into the nighttime hours


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[PowellVolz]

...Mid-South Vicinity...

A concerning scenario appears to be developing across portions of the MO Bootheel, northeast AR, western TN/KY and far northwest MS vicinity during the afternoon/evening. At least mid-60s F dewpoints are expected beneath modest midlevel lapse rates. This will support 1500-2000 J/kg MLCAPE amid intense vertical shear. Forecast soundings indicate 0-1 km SRH increasing to around 400 m2/s2 by early afternoon. Thunderstorms are expected to develop by early afternoon ahead of the cold front within a pre-frontal trough/low-level confluence zone. Storm motion near 50 kt with supercell wind profiles will support cells capable of significant and long-track tornadoes. With time, upscale growth into a QLCS is expected, and intense wind gusts will be possible in addition to mesovortex tornadoes.

...OH/TN Valley vicinity...

Low-level moisture/instability will begin to wane with north and east extent into the nighttime hours. However forecast guidance has consistently shown a few hundred J/kg MLCAPE with little/no inhibition. Forecast guidance generally tends to under-forecast north/east extent of severe potential in strongly forced, intense shear system. As such, the ongoing outlook maintains a broad gradient from Enhanced to Slight risk across this region. Damaging gusts and a few QLCS tornadoes will be possible into the nighttime hours


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Just to add… I absolutely agree with the SPC talking about storms being sustained further east into ETn. Because the QLCS will be well developed beforehand, it doesn’t take much if any surface based instability to keep the strong vertical updrafts going. For example the last system that rolled through had zero surface based instability. I won’t be surprised if the slight and enhanced risks will expand east to include ETn.


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[nrgjeff]

I see why SPC is 'concerned' about the Mid-South. However this RRFS is just one model. Others have a broken line, but not this brutal line of kidney beans. Line is on a prefrontal trough. 

HRRR is beefy (no surprise) but not as intense as the RRFS. ARWs (research WRFs) are split. Old is beefy with some sups, new ARW2 gets sloppy fast. Ditto FV3, which is interesting* because it does OK with storm mode. NAM is doing NAM things, over forced and probably not enough CAPE.

*Interesting in that the sometimes bullish FV3 is a little less intense than some others this time. Still regardless of radar simulations, the environment will be robust CAPE and shear.

At the low levels, surface moisture will surge north. Morning and midday showers should leave outflow boundaries, but cool air may not linger. Strong synoptic system should advect unstable air in as boundaries retreat. One or two pre-frontal troughs is forecast. Boundaries and their intersections will be concerns.

[a5ehren]

HIGH incoming for Memphis at 1630UTC

[nrgjeff]

Yeah, High Risk isn't something we see every day. In fact the Region sometimes skips a year. Only 2-3 nationwide each year. 

Arc of soon to be supercells is developing from Missouri to Arkansas as I type (Noon or just after Central Time). Morning showers left outflow boundaries OFBs. Atmo will destabilize with broken sun. Prefrontal trough(s) to intersect OFBs.

SPC seems to key on southeast of the synoptic triple point TP Iowa/Illinois. Southern stream TP is forecast Mid-South. Some of it is mesoscale, but also southern forcing aloft. 

Not much else to add to SPC. Today is not a chase day. Thinking of those in the risk areas.

Work calls too. This is likely my only post until the true weekend.