Tn Valley Severe Weather

[nrgjeff]

Observed sculped low-top structure on the Cumberland Plateau between Spencer and Sparta, Tenn. However no lightning. Almost reminded me of tropical remnants. Except it's 20 degrees cooler up there (Thursday vs a tropical day lower elevation). The surface wind was howling though.

[Daniel Boone]

5 hours ago, nrgjeff said:

Observed sculped low-top structure on the Cumberland Plateau between Spencer and Sparta, Tenn. However no lightning. Almost reminded me of tropical remnants. Except it's 20 degrees cooler up there (Thursday vs a tropical day lower elevation). The surface wind was howling though.

Yeah, very much acted and looked like a tropical remnants setting. 

[PowellVolz]

Some really big hail right over Egwani golf course




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[PowellVolz]

MCS moving out of Missouri looks good for this afternoon in ETn. Lots of wind damage reports coming in and even some hail. My lawn is a few days from being toast.





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[John1122]

Looks like I'm going to get skipped just tot he north and just to the south. Tough break with the weather on the way next week. May have to go into watering mode.

[nrgjeff]

Same here Friday. Wind blew, and no rain at my house. Lawn was hanging in there, but this week is going to be ugly no matter how much watering. Will water lightly and force the lawn to limp through.

[Windspeed]

[John1122]

Had a heavy shower and a lot of thunder. Once the storm rolled into the Valley it became warned for large hail. 

[jaxjagman]

Went to Brentwood HS,couplet fizzled out,just winds and a light show

[AMZ8990]

Pretty intense in Memphis this afternoon as this storm rolled through.  Came in fast and the winds were intense.  

[AMZ8990]

[jaxjagman]

Last year we had the best fall severe season EVER.Seems like we could possibly see the MJO signal possibly strenghten into the WP as we head into Dec once again.Archive map is from last year and of course this is no forecastJust seems to me we could see a potential uptick in severe typical places like the Ozarks,Mid South,lower MS/Valley into Dec

[nrgjeff]

If the upcoming AK ridge driven cold pattern is brief; then, we can get back to a more La Nina warm pattern. It would tee up chances for late autumn and early winter severe. 

[PowellVolz]

If the upcoming AK ridge driven cold pattern is brief; then, we can get back to a more La Nina warm pattern. It would tee up chances for late autumn and early winter severe. 

Seems like I remember a solid cold snap about this time last year followed by a solid warming trend that lasted a while.


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[nrgjeff]

I'll take an order of Holiday severe weather. 

[nrgjeff]

Mid-South Tuesday will depend on daytime heating. Overcast would delay thunderstorms until overnight, and Tennessee would probably escape severe. Mississippi would still face some risk Tuesday night.

Greater sunshine on Tuesday would promote high temps over 65 maybe 70, and daytime severe thunderstorms. Scenario would also accompany a farther north and east warm sector for Tennessee and Alabama. Finally, the wind profiles are quite robust both speed and direction.

Key to this almost winter set-up is Sunday. The weekend system won't send a front to the Gulf Coast. Sets the table for a quick and perhaps deep moisture recovery by Tuesday afternoon.

[jaxjagman]

 Day 3 Convective Outlook CORR 1
   NWS Storm Prediction Center Norman OK
   0241 AM CST Sun Nov 27 2022

   Valid 291200Z - 301200Z

   ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF
   THE LOWER TO MID MISSISSIPPI VALLEY...

   CORRECTED FOR WORDING

   ...SUMMARY...
   Severe thunderstorms with wind damage and tornadoes, along with some
   hail, will be possible from the Sabine River Valley and lower
   Mississippi Valley north-northeastward into the mid Mississippi
   Valley on Tuesday. A significant severe-weather event will be likely
   across parts of the region.

   ...Lower to Mid Mississippi Valley/Sabine River Valley/Eastern
   Ozarks...
   A highly progressive upper-level trough will move quickly into the
   southern and central Rockies on Tuesday. Ahead of the system, a
   broad 40 to 60 knot low-level jet will transport low-level moisture
   northward across east Texas and the lower Mississippi Valley, where
   surface dewpoints should reach the lower to mid 60s by midday. In
   response to moisture advection and surface heating, moderate
   instability is forecast to develop by early afternoon across much of
   east Texas and Louisiana. Isolated to scattered convective
   initiation will be possible in the early afternoon from near the
   instability axis eastward across the lower Mississippi Valley. A
   severe threat will be possible with this activity.

   Moisture will continue to advect northward into the eastern Ozarks
   and mid Mississippi Valley during the late afternoon and early
   evening. This will set up a broad corridor of moderate instability
   across much of the lower to mid Mississippi Valley. As the
   upper-level trough approaches from the west, the low-level jet is
   expected to strengthen into the 50 to 70 knot range by early
   evening. This combined with increasing deep-layer shear, associated
   with an approaching southern Plains mid-level jet, will make
   conditions very favorable for severe thunderstorms across the lower
   to mid Mississippi Valley. NAM forecast soundings along the axis of
   strongest instability, from northeast Louisiana into eastern
   Arkansas, by 03Z Wednesday have MLCAPE in the 1500 to 2000 J/kg
   range, with 0-6 km shear in the 60 to 70 knot range. This combined
   with a long and looped hodographs, with 0-3 km storm-relative
   helicities in the 400 to 500 m2/s2 range, will be favorable for
   supercells and tornadoes. A few strong tornadoes will be possible
   with the more dominant supercells that remain discrete. The most
   favorable area for strong tornadoes may develop along the western
   edge of the low-level jet, as is forecast by the ECMWF, from eastern
   Arkansas into northwest Mississippi and western Tennessee. A tornado
   outbreak will be possible across parts of the lower to mid
   Mississippi Valley, if the current forecast parameters, such as
   instability, deep-layer shear and low-level shear remain at current
   forecast levels.

   In addition to the tornado threat, the potential for wind damage
   will likely increase during the evening as storm coverage and the
   chance for cell interactions increase. Mid-level lapse rates are
   also expected to be steep, which should support a hail threat with
   the more intense cells. The extent of moisture return will determine
   how far north-northeast the severe threat develops. At this time, it
   appears that at least some severe threat will be possible during the
   evening and overnight period as far north as southern Illinois and
   southwest Indiana. A categorical upgrade will be possible in later
   outlooks.

   ..Broyles.. 11/27/2022

[jaxjagman]

URGENT - IMMEDIATE BROADCAST REQUESTED
   Tornado Watch Number 572
   NWS Storm Prediction Center Norman OK
   1210 PM CST Tue Nov 29 2022

   The NWS Storm Prediction Center has issued a

   * Tornado Watch for portions of 
     Southeast Arkansas
     Northern and Central Louisiana
     Central Mississippi

   * Effective this Tuesday afternoon and evening from 1210 PM until
     700 PM CST.

   ...THIS IS A PARTICULARLY DANGEROUS SITUATION...

   * Primary threats include...
     Numerous tornadoes expected with a few intense tornadoes likely
     Scattered large hail and isolated very large hail events to 2
       inches in diameter likely
     Scattered damaging wind gusts to 70 mph likely

   SUMMARY...Supercells are expected to develop this afternoon and
   track northeastward across much of northeast Louisiana and central
   Mississippi.  Parameters appear favorable for strong and
   long-tracked tornadoes this afternoon and early evening.

   The tornado watch area is approximately along and 80 statute miles
   north and south of a line from 25 miles north of Fort Polk LA to 55
   miles south of Tupelo MS. For a complete depiction of the watch see
   the associated watch outline update (WOUS64 KWNS WOU2).

[jaxjagman]

[nrgjeff]

Above are the odds of SEEING anything in the South. Odds of it happening may be higher, but hills trees, short daylight hours, peaking after dark, etc..

Could be the same story Tuesday in the Mid South and just southwest of our Region.

 

[nrgjeff]

Day 4-8 looks valid for Monday severe Mid-South. 12Z Wed. is slowing it down, into the flatter Delta region. Nice!

Friday system tugs on Gulf Moisture; then, front does not clear the Coast over the weekend. Perfect for moisture return on Sunday. I always like a second system to ensure deeper moisture return. It’s nice in spring. It’s vital in winter. It’s this set-up.

Then the table is set Monday. Winds turn with height forming a textbook curved hodo. Prefrontal trough is forecast intercepting WF or differential heating boundary. Those are fine details for so far out, but also easy pattern recognition.

Believe SPC is right to outlook Day 6 in the cold season. Second wave (vs one-and-done) adds confidence to the thermo profile. In winter the wind profile is a given.

That said, those who get anxious should not be this far out. Whole thing could fall apart. At the same time, chasers should check their equipment.

[jaxjagman]

Was a quiet year

[Matthew70]

9 hours ago, jaxjagman said:

Was a quiet year

I gotta admit I’m not disappointed.  The one that hit Nashville to Mt.Juliet to Lebanon to Cookeville in my opinion should cover the next 10 years. Then the one that hit NW TN to KY should cover them for the next 10 years. Wx seems to be doing the opposite of what analogs are saying these days.  

[nrgjeff]

Yeah @Matthew70 that was historic. It's almost like we get fewer tornadoes, but the energy is rolled up into several big ones. A look at overall history shows more general tornadoes in the Plains, but the 4s and 5s are concentrated in the South.

Interesting @jaxjagman that 1989 was the last year so quiet in Tenn. Kansas was dead the late 80s too. Kansas is dead now too like Tenn. In both cases last year the states had notable tornadoes (Andover 2.0) but not much activity overall.

Alas the Monday outbreak appears on track but mainly juuust to our west in Arkansas. Best chance of tornadoes is probably the western half of the 15% closer to initiation and the main pre-frontal trough. Could be mostly straight wind into the Mid-South but don't let down your guard yet. Anything going well out ahead on the WF could rotate.

Mid-South looks after dark. Daytime action looks Ozarks. With Bowl Games galore on Monday the choice is clear. No chase!

[jaxjagman]

8 minutes ago, nrgjeff said:

Yeah @Matthew70 that was historic. It's almost like we get fewer tornadoes, but the energy is rolled up into several big ones. A look at overall history shows more general tornadoes in the Plains, but the 4s and 5s are concentrated in the South.

Interesting @jaxjagman that 1989 was the last year so quiet in Tenn. Kansas was dead the late 80s too. Kansas is dead now too like Tenn. In both cases last year the states had notable tornadoes (Andover 2.0) but not much activity overall.

Alas the Monday outbreak appears on track but mainly juuust to our west in Arkansas. Best chance of tornadoes is probably the western half of the 15% closer to initiation and the main pre-frontal trough. Could be mostly straight wind into the Mid-South but don't let down your guard yet. Anything going well out ahead on the WF could rotate.

Mid-South looks after dark. Daytime action looks Ozarks. With Bowl Games galore on Monday the choice is clear. No chase!

Like to see where the MJO these next couple weeks ends up.CFS (if its right) shows it starting to strenghten into the NH /Africa then into the IO.If NINA hangs on i think it will it could get at least interesting into spring,but i thought we'd do better with this NiNA last year

[PowellVolz]

Some interesting talk in this mornings SPC convection outlook. Maybe I just don’t remember them ever doing this but they said mods have a cold bias in the winter and therefore they believe the surface cape will be higher for tomorrow than what the mods are saying. Don’t believe I’ve ever seen them build a forecast in a potentially life threatening situation around a mod biases.


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[nrgjeff]

The surface temps bias of course depends on the situation. Surging Arctic fronts, a forecaster should go colder.

Warm fronts dislodging cold air the chilly NAM can sometimes win. In this case, it's already mild. WF should be stronger than forecast - stronger than winter model climo. Therefore I agree warmer than guidance at least from the Gulf WF south. I'm still not sold on the synoptic WF farther north since it's already raining.

My bottom line: Mississippi late today and tonight. Central and South Alabama Tuesday. Bama requires the boundary intersection survive, and proper upper jetlet alignment. LLJ is forecast to remain in place Tuesday with warm enough surface temps/dews central/south Bama.

[PowellVolz]

SW of Birmingham needs to be watched




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[John1122]

No thunder but a lot of wind with this system. 

[jaxjagman]

Damn Jeff,when did you ever see GOES go warm like that in spring