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Tn Valley Severe Weather

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I got distracted watching stocks, lol! But yes, we have a severe weather problem in Tennessee tonight.

2 hours ago, Matthew70 said:

Surprised no one is talking about possible threat of severe wx

So the models all have Missouri Boot Heel convection going into Kentucky. All clear? Hell no! Let's do some meteorology. 

First of all it's not moving northeast. It's moving due east. That'll anchor the boundary farther south than progged. Gee, that never happens. I am hoping the short-wave ejection will push the boundary to the TN/KY border. If not it's in danger of hanging up near I-40. Frankly breaks my heart to type this. Sometimes we science. Sometimes we pray. 

Anyway, the 850/925 mb charts look more veered than Super Tuesday. Do not expect a repeat. Still, just strong storms disrupt recovery. Psychological damage of just general thunderstorms can't be ignored. Shear will be worse up in Kentucky (or wherever the boundary settles out).

Not Super Tuesday, but not a good night either.

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Tornado Watch coming shortly - https://www.spc.noaa.gov/products/md/md0169.html

mcd0169.gif.a454c473e48f7a3b87349cef50b80532.gif

 

Mesoscale Discussion 0169
   NWS Storm Prediction Center Norman OK
   1113 AM CDT Thu Mar 12 2020

   Areas affected...Southwest MO/MO Bootheel...Southern IL...Western
   KY...Northwest/Middle TN

   Concerning...Severe potential...Tornado Watch likely 

   Valid 121613Z - 121815Z

   Probability of Watch Issuance...80 percent

   SUMMARY...Ongoing thunderstorms as well as the potential for more
   storms this afternoon and evening will likely necessitate Tornado
   Watch issuance within the next hour.

   DISCUSSION...Cluster of thunderstorm currently ongoing across the MO
   Bootheel eastward into far northwest TN/far western KY has shown a
   general strengthening trend over the past hour or so. This cluster
   appears to have been initiated by the low/mid jet streak extending
   from eastern OK into northern AR/southern MO. This jet streak is
   expected to continue eastward throughout the day, providing both
   mesoscale forcing for ascent as well as enhanced low-level vertical
   shear. The ongoing cluster is evidence that the ascent is enough to
   lift parcels to their LFCs and the rotation noted in these cells,
   particularly those over the MO Bootheel and far northwest TN, is
   evidence of the enhanced vertical shear. 

   Expectation is for this cluster to continue northeastward/eastward.
   More eastward moving storms will maintain a closer proximity to the
   warm front extending across the region, resulting in access to
   greater low-level moisture and higher surface-based potential.
   Current surface analysis places the warm front from just south of
   the MO Bootheel east-northeastward to BNA. Primary threat with the
   elevated/more northeastward-progressing storms will be hail, but the
   more surface-based/eastward-progressing storms will also have the
   potential to produce damaging wind gusts and tornadoes. These
   threats will likely prompt watch issuance within the next hour.

   ..Mosier/Hart.. 03/12/2020

   ...Please see www.spc.noaa.gov for graphic product...

   ATTN...WFO...LMK...OHX...PAH...MEG...

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Big time hook echo about 15 or 20 miles north of me in Southern Kentucky in that warned storm. Hope our SE Kentucky folks are okay. 

That cell has had at least broad rotation for a long time. Look at the meso track of this storm 9eda08dd60074188aa27daaa7996891f.png


.
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Like Jeff mentioned in his post on the 5th.The Upper level Ridge is fixing to get kicked out to the east around the middle of next week.Right now the Euro and GFS both has a system coming off the Lee.Like always at this range in time we'll have to keep watching, but right now seemingly we should be looking at some possible strong storms towards the end of the work week into the weekend time frame.

 

 

 

AAM GWO Mapwall (1).png

ERTAF (1).png

ERTAF (2).png

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2 hours ago, CheeselandSkies said:

CPC has had this in their hazards outlook for a few days now. SPC Day 4-8 hints at it in their wording but they're still reluctant to commit to delineating a risk area.

See what happens,the GFS has already shifted the Upper level ridge further east tonight and shows a stronger system,just timing

gfs_z500a_us_29.png

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Looking like lots of volatility in the upcoming pattern trying to figure out the mid range into the long range,The trough is coming off East Asia today which already looks like a cluster mess, so it looks like we'll see all kinda of changes upcoming

ECMWF Model - Tropical Tidbits.png

6ef03071-2b9c-4bd5-9b30-7c5dfb0e95a3.gif

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Would think we could see a slight risk the next upcoming update.GFS and Euro aren't far off but still some timing this afternoon with synoptics on the 12z run today

 

Day 4-8 Convective Outlook  
   NWS Storm Prediction Center Norman OK
   0357 AM CDT Fri Mar 20 2020

   Valid 231200Z - 281200Z

   ...DISCUSSION...
   ...Monday/Day 4 and Tuesday/Day 5...
   On Monday, the medium-range models move a shortwave trough across
   the southern Plains. A moist airmass is forecast to advect northward
   into the Red River Valley with a dryline setting up across western
   Oklahoma and northwest Texas. Scattered thunderstorm development
   will be possible to the east of the dryline Monday afternoon. Strong
   deep-layer shear associated with a 75 to 90 kt mid-level jet is
   forecast to create conditions favorable for severe storms.
   Supercells and bowing line segments will be possible with a
   potential for tornadoes, wind damage and large hail. The magnitude
   of the threats will likely depend upon how much moisture can return
   northward and how much instability can develop on Monday. At this
   time, the potential for a severe weather event appears great enough
   to warrant adding a 15 percent area.

   On Tuesday, the shortwave trough is forecast to move eastward across
   the Mississippi Valley. A moist airmass is forecast to be in place
   in most of the southeastern states. Scattered thunderstorms will be
   possible across parts of the Ohio and Tennessee Valleys where enough
   instability and deep-layer shear should be in place for a severe
   threat. A tornado threat along with potential for wind damage will
   be possible Tuesday afternoon and evening. A threat area could be
   added as confidence increases concerning where the greatest severe
   threat will be.

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I expect Tuesday will get an Outlook on Saturday morning or soon after. Euro remained consistent if not stronger. LLJ is a touch veered, but not like the last two systems. It's fortunately not backed like Super Tuesday either. Upper level winds are a given. Low level theta E (temps/humidity) will be a question. Even with all those caveats, if the Euro holds, one has to think Tuesday gets a 15%.

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On 3/21/2020 at 8:23 AM, Runman292 said:

I got a question. When was the last significant severe weather outbreak in East TN? Is it April of 2011?

Not sure you should use sig severe outbreak.Outbreak is a outbreak but i know what you mean.Nothing anywhere would compare to 2011

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NWS Storm Prediction Center Norman OK
   0146 AM CDT Sun Mar 22 2020

   Valid 241200Z - 251200Z

   ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF
   THE MID MISSISSIPPI...OHIO AND TENNESSEE VALLEYS...

   ...SUMMARY...
   Thunderstorms associated with wind damage, a tornado or two and hail
   will be possible in the mid Mississippi, Ohio and Tennessee Valleys
   on Tuesday.

   ...Mid Mississippi/Ohio and Tennessee Valleys...
   A shortwave trough is forecast to move quickly eastward into the Mid
   Mississippi Valley on Tuesday. A large cluster of thunderstorms,
   associated with a marginal severe threat, should be ongoing Tuesday
   morning just ahead of the shortwave trough in central and
   southeastern Missouri. This convection, located on the northern edge
   of the moist sector near a surface low, is expected to move eastward
   across southern Illinois and into parts of western Kentucky around
   midday. Surface dewpoints should reach the lower to mid 60s F by
   afternoon across much of southern Kentucky, Tennessee and northern
   Mississippi. In response, MLCAPE may increase into the 800 to 1000
   J/kg range from just south of the Ohio River southward into northern
   Mississippi. Surface-based thunderstorms that develop in this area
   Tuesday afternoon could obtain a severe threat due to the strong
   deep-layer shear in place. O-6 km shear is forecast to be in the 70
   to 80 kt which would be favorable for supercells and bowing line
   segments. Although wind damage would be the primary threat, hail
   would also be possible with the stronger updrafts. Low-level shear
   is also forecast to be sufficient for an isolated tornado threat.

   Large-scale ascent and deep-layer shear is forecast to be strong
   ahead of the short-wave trough. This may be enough for squall-line
   development during the late afternoon across the Ohio and Tennessee
   Valleys. If this occurs, the wind damage threat could be maintained
   into early evening. A chance for QLCS tornadoes would be possible,
   associated with rotating cells embedded in the line. Due to the
   potential for a severe convective line, the slight risk has been
   expanded eastward across much of middle Tennessee and central
   Kentucky.

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Euro starts to kick  in the LL/Shear into the morning and afternoon Tuesday,more into the western and possibly the Middle Valley.,could get some supercells develop.NAM shows the TT'S  52-54 mid afternoon into Mid Valley but like always it could be over doing it but it did do well IMO when Nashville had its Tornado recently even at this range,still wouldnt trust it.Like BNA stated it should go into a QLCS Tuesday as it progress eastward with mesocyclones possibly embedded.

Much as i like severe weather,i'm hoping this won't happen this time,anywhere :(

 

ational Weather Service Nashville TN
216 PM CDT Sun Mar 22 2020

.DISCUSSION...

Showers are showing up on radar just off to the west of the TN
River currently, and moving eastward. Rain will continue eastward
through the afternoon and evening, and still expecting the
heaviest rainfall after midnight for areas south of I-40. Around
an inch to an inch and a half will be possible closer to the AL
border as the upper trough moves through the OH River Valley
tonight. Left in mention of thunderstorms in the southern zones
where some instability will work its way into the area overnight.
Showers should come to an end from west to east during the day,
with some lingering showers holding on in the afternoon on the
Plateau. Monday night early on looks to be dry as we will be
between troughs, but the next stronger Plains trough will be
moving eastward and start impacting the area Tuesday morning.

Warm air will already be in place from the previous trough, but
the next trough will bring a warm front through the area Tuesday
morning after sunrise, allowing more warm moist air to spread over
the region. Model soundings show a shallow low level inversion
that should limit convection early on, but once the warm front
passes through, the mid state will be uncapped in the warm sector
for the rest of the morning and afternoon. The GFS/NAM have
heavier showers and thunderstorms mainly along the I-40 corridor
and northward Tuesday before noon, and enough instability is
around for some strong to severe storms during that time. After
the warm front passes, there may be a brief break before
additional storms develop ahead of the cold front in the warm
sector during the afternoon, and spread eastward. As the trough
and its axis approach the mid state, both instability and shear
increase, along with low level helicity. MLCAPE values around 500
to 1000 J/kg look likely across the area during the afternoon,
with the NAM not surprisingly showing slightly higher values.
Deep layer shear is consistent between the models, however,
showing 60 to 70 knots from 0-6km. Low level shear and helicity
increase mid afternoon through the early evening, with 0-3km
helicity values around 300 m2/s2 during that time. Model
soundings also showing some decent dry air aloft, with mainly
moist adiabatic lapse rates later in the afternoon. Better mid
level lapse rates exist in the morning before earlier convection
works it over a bit. All of this would suggest that damaging winds
will be the primary threat, and could occur from late morning
through the mid evening. Hail looks more likely in the late
morning through mid afternoon, and will also be more likely with
any isolated stronger convection that develops ahead of the squall
line/QLCS. A few tornadoes can also not be ruled out, but as of
right now, look more likely from mid afternoon to the early
evening when convective mode looks more linear/QLCS-like. 00Z
models tonight and even 12Z runs tomorrow morning will hopefully
paint a better picture and help narrow down timeframes a bit more
for Tuesday.

AccuWeather com® Professional - Forecast Models.png

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We got throttled March 2012. 

On 3/21/2020 at 9:23 AM, Runman292 said:

I got a question. When was the last significant severe weather outbreak in East TN? Is it April of 2011?

I've nothing much on this week. Veered off trash. Only turning is in the Ohio River Valley jungle. 

Back to NCAA Basketball reruns!

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I agree we don’t need any severe weather at this point but if we are looking for a positive in this, it looks like the system will not produce prolonged rain which we obviously do not need.


.

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3 hours ago, PowellVolz said:

I agree we don’t need any severe weather at this point but if we are looking for a positive in this, it looks like the system will not produce prolonged rain which we obviously do not need.


.

Yes and should wait and see if/where any triple point sets up Tues afternoon,think the question will be how far the warm front lifts north

WPC s Short Range Forecasts  Days 0 5 - 2 5  - NDFD Precipitation.png

SPC SREF SREF_prob_combined_sigtor_.png

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   Day 2 Convective Outlook  
   NWS Storm Prediction Center Norman OK
   1258 AM CDT Mon Mar 23 2020

   Valid 241200Z - 251200Z

   ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS THE
   TENNESSEE VALLEY...

   ...SUMMARY...
   Thunderstorms associated with wind damage, a tornado or two and hail
   will be possible in the mid Mississippi, Ohio and Tennessee Valleys
   on Tuesday.

   ...Mid Mississippi Valley/Ohio and Tennessee Valleys...
   A fast-moving shortwave trough will move eastward into the mid
   Mississippi Valley on Tuesday. At the surface, a low will move
   eastward into the Ozarks with a warm front extending eastward from
   the low into the Tennessee Valley. Thunderstorms associated with a
   marginal severe threat will be likely to the northeast of the
   surface low across southern Missouri during the morning. As the low
   moves eastward, low-level flow will strengthen across the Tennessee
   Valley. In response, low-level moisture will increase with surface
   dewpoints reaching the lower to mid 60s F from northern Mississippi
   into western Tennessee. Surface heating should enable MLCAPE to peak
   in the 500 to 1000 J/kg range by afternoon. Surface-based
   thunderstorms appear likely to develop across just ahead of the
   approaching shortwave trough. This convection is forecast to move
   eastward across the Tennessee Valley during the afternoon reaching
   the southern Appalachians by early evening.

   Forecast soundings across the Tennessee Valley Tuesday afternoon
   show strong deep-layer shear profiles and steep low-level lapse
   rates. 0-6 km shear is forecast to be 65 to 75 kt range which should
   be favorable for supercells and short bowing line segments. A
   tornado threat, along with a potential for wind damage and hail will
   be possible with supercells. Short line segments should also be
   capable of producing wind damage. The severe threat is expected to
   become isolated as scattered thunderstorms move eastward into the
   southern Appalachians and southeastward into the central Gulf Coast
   States during the evening.

   ..Broyles.. 03/23/2020

Storm Prediction Center Mar 23  2020 0600 UTC Day 2 Convective Outlook.png

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It seems quite likely that scattered severe storms will move across Tennessee and Kentucky, as well as adjacent areas of Mississippi and Alabama. According to most CAMs, the storms may be quite late in the day, with some stronger storms at 00z (8:00PM eastern/7:00PM central). With strong wind fields aloft, these storms will have fast movement, and I would expect a wind/tornado threat

aLTthnk.png

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Day 1 Convective Outlook  
   NWS Storm Prediction Center Norman OK
   0745 AM CDT Tue Mar 24 2020

   Valid 241300Z - 251200Z

   ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS THE
   MID-SOUTH/TENNESSEE VALLEY...

   ...SUMMARY...
   Scattered severe storms, including the potential for hail/wind
   damage along with a few tornadoes, are expected over the Mid-South,
   Tennessee Valley, and southern Appalachians vicinity.

   ...Mid-South/Tennessee Valley to southern Appalachians...
   Bands of elevated showers/thunderstorms are ongoing early this
   morning across the Ozarks into much of Tennessee and northern
   portions of Mississippi and Alabama. A low-amplitude shortwave
   trough/mid-level speed max over the south-central Plains and Ozarks
   early today will steadily progress eastward, reaching the Tennessee
   Valley by early evening. In response to this feature, a weak surface
   low will shift into Arkansas by early afternoon as the frontal zone
   that is currently draped across the central Gulf States lifts north
   toward the Tennessee border. This surface low will then track along
   the wind shift into middle Tennessee by early evening.

   Diurnal heating will be maximized ahead of the surface low across
   Arkansas where low-level flow should veer and surface temperatures
   should reach convective temperatures by mid-afternoon. Surface-based
   supercells are expected to initially develop across eastern Arkansas
   into western Tennessee/northern Mississippi within the warm sector
   and near the warm front. This activity will develop within strong
   deep-layer shear, but low-level shear is not forecast to be
   particularly strong initially given the southwesterly surface winds.
   The surface-based nature of these storms suggests all hazards are
   possible, including a few tornadoes. Hail will be the primary risk
   north of the warm front.

   While exact later-day positioning of the warm front is a bit
   uncertain, there is concern that a somewhat more focused/heightened
   supercell and tornado potential could materialize across portions of
   Middle Tennessee and northern Alabama in vicinity of the surface
   triple point. Near the modestly deepening surface low/warm front,
   low-level shear/SRH will be maximized with an enlargement of
   hodographs expected toward sunset. Portions of Middle Tennessee and
   northern Alabama will be reevaluated later today for the possibility
   of a higher risk category (Enhanced).
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Big changes since Sunday. Instead of Ohio River Valley jungle, we now have an outflow boundary in North Alabama and just south of KCHA. Still plenty of failure modes.

A. Rain-out

B. Veered off

C. Capped (too little too late)

D. Combo of 2-3 above

E. Rather watch sports reruns

Early season is prone to failures, which is of course good for the general public. That said I figure ENH is incoming.

Obviously if something is close to KCHA I'll take a look. No chase greater than 2 hours though; so, I won't be visiting the chasable northwest Bama area today.

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URGENT - IMMEDIATE BROADCAST REQUESTED
   Tornado Watch Number 61
   NWS Storm Prediction Center Norman OK
   305 PM CDT Tue Mar 24 2020

   The NWS Storm Prediction Center has issued a

   * Tornado Watch for portions of 
     Northern Alabama
     Northeastern Mississippi
     The southern half of western and middle Tennessee

   * Effective this Tuesday afternoon and evening from 305 PM until
     1000 PM CDT.

   * Primary threats include...
     A few tornadoes likely with a couple intense tornadoes possible
     Scattered damaging wind gusts to 70 mph likely
     Scattered large hail events to 1.5 inches in diameter possible

   SUMMARY...Scattered supercell development is expected in the next
   couple of hours from western Tennessee and northeastern Mississippi
   into northern Alabama and southern middle Tennessee.  The storm
   environment will be favorable for tornadoes, including a strong
   tornado or two, in addition to damaging winds and large hail. 
   Storms will spread eastward through late evening.

   The tornado watch area is approximately along and 95 statute miles
   east and west of a line from 85 miles north of Huntsville AL to 55
   miles south southwest of Muscle Shoals AL. For a complete depiction
   of the watch see the associated watch outline update (WOUS64 KWNS
   WOU1).

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