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?

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?

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

Perhaps it is just me, but it feels like a lot of severe weather doesn't impact East TN until sunset or later when instability is lower. 

Looks like a line is forming west of Nashville. 

17 minutes ago, John1122 said:

Not sure how they didn't issue a tornado watch here. 

Finally got that Tornado watch until 2 am.

6 minutes ago, John1122 said:

Not sure how they didn't issue a tornado watch here. 

This was posted 25 minutes ago.

Probability of Watch Issuance...60 percent

   SUMMARY...A tornado watch may be needed across eastern Tennessee and

   potentially into far western North Carolina.

   DISCUSSION...A supercell has moved east of watch 79 across eastern

   Tennessee. Additional storm development is questionable as

   widespread thunderstorms have developed to the west with anvil

   debris across much of eastern Tennessee. However, at least scattered

   supercell development remains possible through early evening. The

   MRX VWP currently shows less than 100 m2/s2 0-1km SRH with the

   stronger low-level jet to the west. This wind profile is expected to

   increase after 00Z as this low-level jet slowly moves east. A

   tornado watch will eventually be needed this evening, as low-level

   shear and storm coverage increases.

Someone reported seeing a tornado touchdown with debris at Pilot Mountain.

MRX has released their AFD early:

Discussion:

The main impact in the forecast period will the the probability for severe thunderstorms later this afternoon through the early overnight hours. Much of the CAM guidance this morning has struggled with ongoing convection with a wide variety of potential outcomes for storm mode and evolution through the overnight hours. However, models have consistently shown 500 to 1500 J/Kg of MLCAPE late this afternoon into the early overnight hours with strong effective bulk shear of 60 to 60 kt with effective low-level shear around 30 kt. Hodographs are showing the potential for some significant length and curvature at times which would create a favorable environment for supercell structures that could coalesce into a QLCS line later this evening with embedded rotation. Current satellite and observations show a wide area of upper divergence across northern Mississippi and West Tennessee that will continue to transition eastward with the upper jet through the evening. Stronger DPVA will result in height falls, moreso after 21z today which will continue to erode the mid-level CAP and increase instability. Current observations show dew points in the low to mid 60s across the Tennessee Valley with a general surge northward through the evening as southwesterly flow increases across the area. All of this points to severe thunderstorms continue to be expected across much of the Tennessee and Ohio Valleys with the potential for damaging winds, hail, and tornadoes.

Sun is trying to come out in Oak Ridge.

Here's a funny gaffe. 10 news was posting about the Tornado watch that was issued for Southeastern KY, but their graphic says tornado warning. 

Newest update from MRX:

Forecast is on track this morning with severe weather potential expected later this afternoon and evening. Surface obs show a region of low to mid 60s dewpoints stretching from northern AL, through Middle TN, and southeast TN. With additional surface heating through the afternoon, models continue to show MLCAPE around 1000 J/Kg being likely combined with low level shear of 30+kt and bulk shear of around 50 to 60 kt. Model guidance shows fairly large, curved hodographs bringing a potential of mixed mode supercells and QLCS storms through the evening.

Many of the CAMs this morning are having a difficult time resolving ongoing convection across the Tennessee and Ohio Valleys. In particular, the HRRR does not seem to be doing a great job with initialization at this time. With the available guidance, you can find a CAM to fit your priors of a very active severe weather event to a more quiet event. The main thing to focus on is that we will have sufficient instability and shear for severe weather - including damaging winds, large hail, and tornadoes - later this afternoon and evening. The severe weather risk remains unchanged with the potential for a fairly widespread severe event across portions of the Tennessee and Ohio Valleys late this afternoon through the early overnight hours.

Is it just me, or does it seem like this system is going to arrive in East TN faster than the 6 PM time frame that the local Mets are saying?

Looks like it's going to be a busy day. 

   ...THERE IS A MODERATE RISK OF SEVERE THUNDERSTORMS ACROSS THE OHIO

   VALLEY...

   ...SUMMARY...

   A potentially substantial severe weather outbreak -- possibly

   including a few significant/long-track tornadoes -- is anticipated

   this afternoon and evening, with the highest probability centered

   over the Ohio Valley. Severe risk exists as far south as the Gulf

   Coast, and as far east as western portions of Virginia and the

   Carolinas.

   ...Discussion...

   Strong northern-stream upper low, currently located over southern

   MB, is forecast to drop south across MN into northern IL late in the

   period. This evolution is driven in part by a 500mb speed max that

   will translate across the central Plains, increasing to near 100kt

   over eastern KS/OK by 03/12z. Intense 12hr midlevel height falls are

   forecast across much of the Great Lakes, OH/TN Valley, and the

   northern Gulf States, where values in excess of 200m are expected

   during the latter half of the period. Synoptic front that is

   currently draped across the OH Valley will be encouraged to

   gradually advance north due to the digging trough; however, an

   extensive corridor of convection currently extends across the MS

   Valley into the OH valley, which is maintaining cool boundary-layer

   conditions north of I-70.

   Latest water-vapor imagery suggests a southern-stream short-wave

   trough is progressing across eastern KS/eastern OK. This feature

   will progress downstream and likely aid early-day thunderstorm

   development near the confluence of the MS/OH Rivers. Seasonally high

   PW airmass currently extends across northern AR/southern MO into

   southern IL. NAM forecast sounding for JBR at 15z exhibits 60kt

   surface-6km bulk shear with SBCAPE on the order of 1500 J/kg.

   Discrete supercells may evolve ahead of this feature then

   spread/develop northeast across southern IN/KY into OH. Some

   uncertainty exists across northern OH/IN regarding destabilization.

   It's not entirely clear if ongoing convection will allow the warm

   front to lift appreciably north of its current position. However,

   large-scale pattern is quite dynamic and favors surface low

   deepening over southern Lake MI during the latter half of the

   pattern. NAM struggles to reflect this scenario, thus weaker

   instability is forecast at higher latitudes. Tornadoes, damaging

   winds, and large hail are expected with supercells that evolve

   across the warm sector. Some tornadoes may be long-lived and strong.

   Farther south, a bimodal severe threat may ultimately evolve with a

   secondary corridor of more concentrated severe across portions of

   the northern Gulf States. 500mb speed max is forecast to eject

   across northern Mexico into TX by 03/00z. This feature will

   intensify as it translates across LA into eastern TN by the end of

   the period. There is some concern that severe probabilities may need

   to be increased across this region to account for this low-latitude

   speed max during the evening/overnight hours. Strong shear will

   support supercells along with a threat for tornadoes, damaging

   winds, and hail.

Just got a rare Destructive winds tag on the Warned storm in Knox County. 

Newest AFD from MRX:

Cumulus development is ongoing across central Kentucky which is
increasing confidence that the ingredients needed to create a severe
weather event are actually materializing this morning. Initiating is
ongoing near the strengthening LLJ as the aggressive shortwave moves
through. Mesoanalysis shows that all the severe parameters are
impressive this morning and with clouds clearing out this morning
the debris CU doesn`t look like it`s going to get in the way of
increasing instability in the low levels of the atmosphere. All
weather threats are possible today, including rotating supercells.
Based on current radar trends and refreshed CAMs the timing of
incoming storms has slowed down just a tad compared to previous
forecast with storms looking to move onto the plateau around noon
and quickly moving eastward, pushing east of the mountains before
sunset.

Main weather message for today is to keep an eye radar and the
latest warnings, especially for the commute home from school or work
as this is the peak time frame for severe storms.

Not liking the fact that MRX is highlighting an increased hail threat in their afternoon AFD.

Enhanced risk for most of TN including the western half of East TN this evening.

...Mid-South/TN Valley region through tonight...
   Around the southern periphery of a closed midlevel low over the
   upper Great Lakes, embedded shortwave troughs will move eastward
   over the lower OH and TN Valleys through early tonight.  An
   associated surface cyclone will likewise develop eastward along and
   just north of the OH River, as a trailing pre-frontal trough and
   cold front move southeastward across the Mid-South and southern
   Plains through tonight.  Clouds are fairly widespread as of late
   morning from the southern Appalachians northward into the OH Valley
   and westward into the mid MS Valley.  A little south of the thicker
   clouds and surface cyclone track, there is a corridor of stronger
   surface heating from south central KY into the Mid-South, where
   temperatures will warm into the 80s with mid-upper 60s dewpoints. 
   These surface conditions beneath midlevel lapse rates of 7-7.5 C/km
   will drive MLCAPE of 1500-2500 J/kg with minimal convective
   inhibition.

   Scattered thunderstorm development is expected by early-mid
   afternoon in the zone of weak low-level confluence/convergence
   associated with an embedded midlevel speed max, along the edge of
   the thicker clouds from central KY into western TN and AR.  The
   moderate-strong buoyancy and midlevel flow near 40 kt will support a
   mix of multicell clusters/line segments capable of producing
   damaging winds and large hail.  There will be somewhat stronger
   deep-layer flow/shear and a little greater potential for supercells
   across the Mid-South later this afternoon/evening.  The convection
   will continue to spread eastward and southeastward across the TN
   Valley early tonight, with some continued damaging-wind threat.

   Other scattered thunderstorms could form this afternoon/evening to
   the west of the thicker clouds across the southern Appalachians. 
   The stronger wind profiles/vertical shear will be west and north of
   this area through the afternoon, so the primary severe threats will
   be damaging downburst winds and marginally severe hail this
   afternoon/evening.  Uncertainty increases with eastward extent due
   to the widespread clouds/rain from northeast GA into western NC and
   vicinity, and the primary increase in flow/shear will tend to occur
   after the muted diurnal cycle. 

Scratch my last post. It is a good snow showering in North Knoxville at my church.

Flurries in North Knoxville.

97 mph wind gust reported at cove mountain.

The sun is out in Farragut and it is very windy.

Tornado watch for the rest of Middle TN into the western half of East TN until 5:00 PM EST

On 3/2/2023 at 7:51 AM, PowellVolz said:

When was the last High Wind Warning issued for the valley?


.

The last time a High Wind Warning was issued for all of East TN was 2006. 

Something I found interesting in MRX'S AFD and the most recent day 1 outlook from the SPC is the wording "Winds may be strong enough to tear apart storms and keep them from becoming mature." Can anyone explain to me how that works?