April 12 Severe Threat

[nrgjeff]

Definitely still keep an eye on it have your weather radio set up. I'm just naturally a cynic. Also Middle Tennessee I don't feel is in as good of shape as here in East Tenn.

1 minute ago, Matthew70 said:

So really no reason to worry here in mid TN?  Just possibly high winds and lots of rain?

 

[jaxjagman]

1 hour ago, nrgjeff said:

Definitely still keep an eye on it have your weather radio set up. I'm just naturally a cynic. Also Middle Tennessee I don't feel is in as good of shape as here in East Tenn.

 

Don't trust any model.I agree with you i thought the HRRR would show a little more like the NAM and RAP.The HRRR the last severe event for us a couple days ago, missed the inversion breaking sooner than later, this is one reason it wasn't as severe like it was showing but the RAP just to give it credit showed  this on the CAMS,but it still wasn't picture perfect either tho.

[PowellVolz]

That's close to Yazoo,MS,i dont know what it is about that town but they are a tornado magnet

And Cullum Co Alabama.


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[PowellVolz]

Definitely still keep an eye on it have your weather radio set up. I'm just naturally a cynic. Also Middle Tennessee I don't feel is in as good of shape as here in East Tenn.
 

Interesting. I thought MTn, especially SMTn would end up getting the brunt of this


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[jaxjagman]

9 minutes ago, PowellVolz said:

And Cullum Co Alabama.


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Spiked up from 60 to 75% in Alabama to the Tn border

[McMinnWx]

Just now, jaxjagman said:

Spiked up from 60 to 75% in Alabama to the Tn border

What is this graphic?

[jaxjagman]

2 minutes ago, McMinnWx said:

What is this graphic?

Indices put together for a chance of a significant tornado or tornado

[PowellVolz]

Spiked up from 60 to 75% in Alabama to the Tn border

Oh gees... depending on the track of the storms, that’s a southern valley pipeline. I’m extremely interested in seeing if the mountains help back the winds like they did in 2011 or if they influence rotation. We were lucky that beast that tracked from Monroe to Blount Co stayed in the mountains.


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[jaxjagman]

If the virus wasnt going on right now i'd go towards Yazoo,Ms,but i'm not leaving the state

[jaxjagman]

If its to be believed the RAP would be rather impressive in the Western Valley with DP'S hitting the lower 70's after the inversion would break the storms would grow rather rapidly upscale

[Bob's Burgers]

HRRR trends for tomorrow morning

[McMinnWx]

Those latest STPs are scary. 

[PowellVolz]

HRRR trends for tomorrow morning

This looks like the WF stays south of Tennessee IMO.


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[jaxjagman]

Surprised they still trust the NAM

 

National Weather Service Nashville TN
1028 PM CDT Sat Apr 11 2020

.UPDATE...
FOR EVENING DISCUSSION.

&&

.DISCUSSION...

Made some minor tweaks to sky conditions and potential some light
rain moving into southwestern portions of mid state approaching
12/06Z per regional radar and satellite imagery. Current
temperatures trends in line with forecasted lows. Tweaked hourly
temperature, dewpoint, and wind speed/direction grids. 12/00Z NAM
coming in but GFS is still 11/18Z. Had enough confidence in
11/12Z & 11/18Z model runs depiction/guidance and saw no reason it
would radically change in the upcoming suite of 12/00Z model runs
to do the following. With WPC placing late this afternoon mainly
southern and eastern portions of mid state in a moderate risk of
excessive rainfall for Sunday afternoon through Sunday night,
issued a Flash Flood Watch for areas near and across these
locations from noon Sunday through 7 AM CDT Monday for Cumberland
Plateau Region earlier this evening. Two to three inches, with
training convection resulting in localized possiblity of 4 to 6
inches, especially across southeastern portions of Cumberland
Plateau Region where warm frontal passage might occur Sunday
evening, is expected. Strong low level jet dynamics are expected
to develop by the mid morning hours on Sunday and persist with
approaching and even after surface frontal passage on Sunday
Night. This due to pronounced upper level troughing moving across
mid state region late Sunday night into morning hours on Monday.
Surface winds will initially be orientated southeasterly by the
mid morning hours on Sunday but will veer south to southwest to
eventually west by late Sunday night. Sustained surface winds
will generally 15 to 25 mph, but gusts to around 45 mph possible.
Taking a quick look, 12/00Z NAM still holding trend of its
previous model runs showing mid state more conducive to severe
weather development on Sunday night.

 

 

[yoda]

[jaxjagman]

3 hours ago, PowellVolz said:

This looks like the WF stays south of Tennessee IMO.


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Could be some super cells develop into the late afternoon into the early evening in the western valley.Seems to be showing a cap into the afternoon but after the cap breaks

[yoda]

[jaxjagman]

21 minutes ago, yoda said:

 

22 minutes ago, yoda said:

 Day 1 Convective Outlook  
   NWS Storm Prediction Center Norman OK
   0102 AM CDT Sun Apr 12 2020

   Valid 121200Z - 131200Z

   ...THERE IS A MODERATE RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS
   SOUTHEAST AR...NORTHERN LA...MUCH OF MS...NORTHERN AND CENTRAL AL
   AND FAR NORTHWEST GA...

   ...SUMMARY...
   An outbreak of severe thunderstorms is likely today into tonight,
   with the greatest threat expected from Louisiana through much of the
   Southeast and Tennessee Valley. Strong tornadoes, widespread
   damaging winds, and large hail are all possible.

   ...Synopsis...

   An outbreak of severe storms is expected today across portions of
   the Lower MS Valley into the Southeastern U.S. Intense storms
   capable of widespread damaging winds, large hail, and several strong
   tornadoes are possible with several rounds of storms from late
   morning into the overnight hours. 

   ...ArkLaTex into the Southeast...

   Initially, convection is expected to be ongoing across east TX this
   morning, in association with a lead shortwave perturbation. Storm
   mode may be messy with this area of convection as it spreads
   east/northeast across northern LA/southern AR into northern MS and
   the TN Valley vicinity. However, strong warm advection will bring
   upper 60s to low 70s F dewpoints as far north as I-20 by late
   morning/middday, as a 50+ kt southwesterly low level jet overspreads
   the lower MS Valley. As a result, any convection that is initially
   elevated above a modest EML should quickly become surface based.
   Additional convection is then expected to develop by early afternoon
   as a weak cap erodes across central and southern MS along a
   pre-frontal trough/confluence band. These storms will likely be more
   classic semi-discrete supercells, and spread eastward into AL by
   late afternoon, and northern GA during the evening. Large, curved
   hodographs and deep, rich boundary layer moisture in intense
   vertical shear will support long-lived supercells capable of
   producing significant tornadoes. Overnight, there is some potential
   for upscale growth into a LEWP/QLCS across eastern AL/GA into the FL
   Panhandle. Damaging wind and mesovortex tornadoes are possible with
   this convective mode as well. 

   Further east, strong surface heating and increasing dewpoints will
   result in weak destabilization across the Carolinas in the vicinity
   of a weak surface trough. Upper forcing will remain weaker across
   this area, limiting storm coverage. However, a few cells could
   become intense, capable of a couple of tornadoes and severe
   wind/hail during the afternoon.

   ...Ozarks Vicinity to Lower OH Valley...

   Additional convection is expected to develop in association with the
   main mid/upper shortwave trough ejecting across the southern Plains
   through 00z, then northeastward across the OH Valley overnight.
   Storms are expected to develo across eastern OK during the afternoon
   and spread eastward into southern MO and AR. Some semi-discrete
   cells are possible initially, and will be capable of producing very
   large hail. However, low level shear will become veered and deep
   layer flow more parallel to a surface cold front, resulting in some
   upscale growth into one or more bowing segments. This could result
   in a corridor of intense, damaging winds from northern AR into
   western TN/KY during the evening/overnight hours. In addition to
   damaging wind potential, mesovortex tornadoes also will be possible
   with this activity. 

   ...Mid-MS Valley into the Central Appalachians...

   Isolated thunderstorms are possible during the afternoon across
   northern MO into southern IA in strong warm advection ahead of the
   surface cold front. Marginally severe hail and wind will accompany
   these storms. During the evening and overnight hours, a surface low
   will continue to deepen as it lift northeast toward the Great Lakes.
   Additional storms will spread across the IN/OH and into portions of
   the central Appalachians posing a threat for locally strong wind
   gusts and isolated hail with the strongest cells.

   ..Leitman.. 04/12/2020

[jaxjagman]

Nice if its right

[jaxjagman]

Would not take much instability,but who knows if its gonna be right

[Calderon]

Not to be left out, but there is a potentially significant wind threat as the low pressure deepens and moves across TN and into KY with gusts over 50mph likely across a large portion of the area.

[1234snow]

Sun is breaking out here in SWVA. Not really related to the main outbreak zone but thought I would share.

Any more sun in the valley could enhance the threat later on.

[jaxjagman]

 URGENT - IMMEDIATE BROADCAST REQUESTED
   Tornado Watch Number 106
   NWS Storm Prediction Center Norman OK
   1040 AM CDT Sun Apr 12 2020

   The NWS Storm Prediction Center has issued a

   * Tornado Watch for portions of 
     Far southeast Arkansas
     Northeast Louisiana
     Northern and central Mississippi

   * Effective this Sunday morning and evening from 1040 AM until
     800 PM CDT.

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

   * Primary threats include...
     Several tornadoes and a few intense tornadoes likely
     Widespread damaging winds likely with isolated significant gusts
       to 80 mph possible
     Scattered large hail and isolated very large hail events to 2
       inches in diameter possible

   SUMMARY...Intense bowing line with a history of several tornadoes in
   northwest Louisiana will progress rapidly east-northeast this
   afternoon. Additional semi-discrete suprecells may develop ahead of
   the line as well across parts of northern and central Mississippi.
   Environment is supportive of several tornadoes, some of which will
   likely be strong in addition to potential widespread damaging winds.

   The tornado watch area is approximately along and 85 statute miles
   north and south of a line from 5 miles north northwest of Monroe LA
   to 20 miles south of Columbus MS. For a complete depiction of the
   watch see the associated watch outline update (WOUS64 KWNS WOU6).

   PRECAUTIONARY/PREPAREDNESS ACTIONS...

   REMEMBER...A Tornado Watch means conditions are favorable for
   tornadoes and severe thunderstorms in and close to the watch
   area. Persons in these areas should be on the lookout for
   threatening weather conditions and listen for later statements
   and possible warnings.

[PowellVolz]

Sun is breaking out in Knoxville


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[McMinnWx]

Very thin cloud cover in Athens.

[Windspeed]

  SPC AC 121630

   Day 1 Convective Outlook  
   NWS Storm Prediction Center Norman OK
   1130 AM CDT Sun Apr 12 2020

   Valid 121630Z - 131200Z

   ...THERE IS A MODERATE RISK OF SEVERE THUNDERSTORMS NORTHEAST
   LA...SOUTHEAST AR...MS...AL...WESTERN GA...SOUTHERN MIDDLE TN...

   ...SUMMARY...
   An outbreak of severe thunderstorms is likely through tonight, with
   the greatest threat expected from northeast Louisiana, Mississippi,
   Alabama, southern Middle Tennessee and western Georgia. Strong
   tornadoes, widespread damaging winds, and large hail are all
   possible.

   ...Synopsis...
   A complex forecast with multiple scenarios possible across a
   broad area from the Lower MS Valley into the TN/OH Valleys and the
   Southeast. A compact shortwave trough over the Edwards Plateau of TX
   will accelerate east-northeast into the Ark-La-Miss by this evening
   and towards eastern KY/TN by the end of the period, in response to
   continued amplification of a large-scale trough over the
   north-central states. 

   ...Northwest LA to northern AL/middle TN...
   An ongoing MCS with a history of several confirmed but brief TDSs
   earlier this morning will continue to move east-northeast along an
   intensifying baroclinic zone across parts of northern/central MS
   into northern AL/middle TN. Tornadoes and damaging winds will be
   likely with this MCS which will include a mixed convective mode of
   bowing segments and potential supercells developing just ahead of
   the cluster on its southern flank. 

   The presence of upper 60s to low 70s surface dew points in much of
   LA and southern MS will spread north and likely reach northern MS to
   western AL between 21-00Z. This should overlap strong low-level
   shear (0-1 km SRH of 400+ m2/s2) as the low-level jet strengthens
   and shifts northeast. The environment will favor embedded supercells
   capable of producing strong tornadoes and damaging winds, the most
   substantial of which may occur from northeast LA through
   north-central MS into northern AL and southern middle TN. There is
   still enough uncertainty with regard to convection outpacing
   stronger surface-based instability (especially with northeast
   extent), as well as the overall convective mode, to preclude an
   upgrade to High Risk.

   ...Southern MS to GA/Carolinas...
   To the south of the initial MCS crossing northern MS/AL into TN, a
   separate pre-frontal band of convection is expected to become
   sustained by early evening from southern MS into central AL. This
   convection will be well east of the synoptic cold front, in an
   environment with moderate surface-based buoyancy and very strong
   vertical shear. A broken band of embedded supercells appears likely
   to develop through the evening and overnight, with an associated
   threat for strong tornadoes and damaging winds. The pre-frontal
   convection should reach the western Carolinas by 09-12z.

   ...Lower Red River Valley to the OH Valley...
   An arc of convection will likely form later this afternoon just
   ahead of the compact shortwave trough and associated surface cyclone
   in eastern OK to northeast TX, within the left-exit region of the
   mid-upper jet. This convection will subsequently spread east then
   northeast across the Mid-South during the late afternoon/evening.
   The northward extent of destabilization in AR/western TN this
   afternoon/evening will depend largely on the intensity and extent of
   the early-day MCS moving from LA into northern MS. 

   Still, steep midlevel lapse rates with the ejecting mid-level wave
   and strong deep-layer vertical shear will favor fast-moving
   supercells and line segments capable of producing large hail and
   damaging winds. The northeast extent of the damaging wind and
   tornado threat into tonight will depend largely on how
   widespread/organized the convection is across northern MS/AL this
   afternoon/evening, and the degree of low-level recovery in the wake
   of that convection.

   ..Grams/Bentley.. 04/12/2020

   CLICK TO GET WUUS01 PTSDY1 PRODUCT

   NOTE: THE NEXT DAY 1 OUTLOOK IS SCHEDULED BY 2000Z
   CURRENT UTC TIME: 1736Z (1:36PM), RELOAD THIS PAGE TO UPDATE THE TIME
        

 

[Windspeed]

Quite a number of QLCS tornadoes have occurred already in the semi-inear line moving out of LA. One in particular appears to have been quite violent near Monroe earlier.

[Holston_River_Rambler]

If that QLCS holds together, the HRRR suggests that it might be making it straight for the southern/ south central parts of the eastern valley

[jaxjagman]

1 minute ago, Holston_River_Rambler said:

If that QLCS holds together, the HRRR suggests that it might be making it straight for the southern/ south central parts of the eastern valley

Finally showing something

[nrgjeff]

Moderate rain moving into Chattanooga. Looking forward to a relaxing stable evening...

Just kidding! WF is trying to lift north, but I just can't get excited with my heat pump on while I'm wearing full sweats.

Real concerns remain from Mississippi through Alabama and perhaps Georgia though. Warm sector gonna be lit, though very sloppy.