March 1-3, 2023 | Severe Weather Outbreak

[Neoncyclone]

Quote

   Mesoscale Discussion 0242
   NWS Storm Prediction Center Norman OK
   0401 AM CST Fri Mar 03 2023

   Areas affected...portions of northern MS/AL...western into Middle
   TN...western KY...far southeast MO...and far southern IL

   Concerning...Severe potential...Watch likely 

   Valid 031001Z - 031230Z

   Probability of Watch Issuance...80 percent

   SUMMARY...A new tornado watch will likely be needed by 13-14z/7-8 am
   CST across portions of the Tennessee and Lower Ohio Valleys.
   Damaging gusts and a few tornadoes will be possible through
   midday/early afternoon.

   DISCUSSION...A quasi-stationary boundary is evident in surface
   analysis extending from west-central TN toward the TN/KY border
   vicinity north of Nashville. Meanwhile, the warm front, demarcating
   mid-60s F surface dewpoints from upper 50s to low 60s F dewpoints,
   is arcing from near Memphis into east-central MS (between Starkville
   and Tupelo) and central AL. Large-scale ascent ejecting into east
   TX, as the mid/upper trough becomes more negatively tilted as of
   10z, will aid in deepening of the surface low over central AR as it
   tracks northeast toward the Lower OH Valley through midday. As this
   occurs, the warm front will lift northward, allowing for
   destabilization of the airmass downstream from WW 59 across parts of
   northern MS into western and Middle TN, and eventually northward
   toward the lower OH River. 

   Ongoing precipitation across parts of western/Middle TN/southeast
   MO/western KY and vicinity lends to some uncertainty with respect to
   the northern extent of severe potential through the morning, and
   possible watch issuance. While a relative minimum in severe activity
   may exist in the short term, as the warm front surges northward
   through mid-morning, forecast soundings in addition to CAMs and
   deterministic guidance suggest organized convection will develop
   northeast from near the MS River through western KY.

   Where the more moist and unstable airmass evolves, sufficient
   low-level instability, in the presence of intense low-level shear
   (aided by a 50-60 kt 850 mb jet), will support organized linear
   convection with perhaps embedded or semi-discrete cells. Damaging
   gusts and a few tornadoes will be possible with this activity
   through midday/early afternoon. A downstream watch will likely be
   needed by around 13z-14z.

   ..Leitman/Edwards.. 03/03/2023

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

   ATTN...WFO...LMK...OHX...BMX...HUN...PAH...MEG...JAN...

   LAT...LON   36008974 36938956 37368926 37688873 37868807 37918734
               37868678 37748655 37208638 36328636 35068661 34518683
               34178714 33848781 33598840 33638940 33788978 34038992
               36008974 

 

[DJKuo]

So HRRR and NAM 3km shows my area (Louisville, KY) not clearing out from the warm frontal convection till around noon BUT real time radar shows me clearing out in the next hr or so. That’s way ahead of schedule.

[ceciliaky]

5 minutes ago, DJKuo said:

So HRRR and NAM 3km shows my area (Louisville, KY) not clearing out from the warm frontal convection till around noon BUT real time radar shows me clearing out in the next hr or so. That’s way ahead of schedule.

It looks like Bowling Green is already out of the rain - I’m just outside of E’town and it looks like we’ll be out of rain soon. Not home to confirm, but I don’t like the looks of it for sure. 

[ceciliaky]

23 minutes ago, ceciliaky said:

It looks like Bowling Green is already out of the rain - I’m just outside of E’town and it looks like we’ll be out of rain soon. Not home to confirm, but I don’t like the looks of it for sure. 

Also, BG is up to 57° at 7am (Eastern) E’town is still around 48°

[DJKuo]

1 hour ago, DJKuo said:

So HRRR and NAM 3km shows my area (Louisville, KY) not clearing out from the warm frontal convection till around noon BUT real time radar shows me clearing out in the next hr or so. That’s way ahead of schedule.

Well rainshield stalled over Louisville. Definitely do not see my area destabilizing much if this continues. 

[snowlover2]

Risk areas creep north some. Enhanced up to Cincy and a 10% tornado area added to KY/TN. Hatched wind area added for even parts of the 15% area near I-70.

[RobB]

 

[ak9971]

4 minutes ago, RobB said:

 

I think the big story here will be the wind with the amount of rain we've had recently. If we get a good line with 60mph gusts, and then more strong wind afterwards I think it has the potential for a lot of tree damage.

[RobB]

15 minutes ago, ak9971 said:

I think the big story here will be the wind with the amount of rain we've had recently. If we get a good line with 60mph gusts, and then more strong wind afterwards I think it has the potential for a lot of tree damage.

Definitely a potential big issue....

[ak9971]

HRRR continues with the linear trend and the very strong LP, getting down to 974 mb on the 12Z HRRR. 

[Snow____]

Cold and rainy. Let’s see how far that warm front lifts. It’s currently 41 here

[ceciliaky]

3 minutes ago, Snow____ said:

Cold and rainy. Let’s see how far that warm front lifts. It’s currently 41 here

I live 30-ish miles south of Louisville. Currently 62 degrees, no rain, and clouds are breaking up in the region. 

[DJKuo]

1 minute ago, ceciliaky said:

I live 30-ish miles south of Louisville. Currently 62 degrees, no rain, and clouds are breaking up in the region. 

What a difference those few miles make. Still on and off rain here in Louisville. Temp at 50F

[Snow____]

31 minutes ago, ceciliaky said:

I live 30-ish miles south of Louisville. Currently 62 degrees, no rain, and clouds are breaking up in the region. 

That’s crazy. Here in Cincy less than 100 miles away it’s 41 and heavy rain right now. 

[ak9971]

New SPC discussion is out. Enhanced risk actually expands east some more. 30% hatched wind all the way into extreme western NC and Virginia now and still includes Cincy/Louisville for our area. They've added a hatched tornado area as well that coincides with their recent discussion that was just posted for additional tornado watches. Certainly seems that SPC thinks it will be an active day in our area although it certainly doesnt feel like it outside right now. Closer to our region they are still talking about some discrete activity but scattered 60-80mph gusts in storms that do form. I'll post HRRR in the next post to not make this one too cluttered.

SPC Latest Outlook

Quote

 SPC AC 031611

   Day 1 Convective Outlook  
   NWS Storm Prediction Center Norman OK
   1011 AM CST Fri Mar 03 2023

   Valid 031630Z - 041200Z

   ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS TN/OH VALLEYS
   TO THE SOUTHERN APPALACHIANS...

   ...SUMMARY...
   Numerous tornadoes and scattered swaths of severe damaging winds are
   probable into this evening from the Tennessee to Ohio Valleys
   towards the southern Appalachians. A few tornadoes may be strong
   (EF-2) with the greatest chance across parts of Kentucky and
   Tennessee.

   ...TN to OH Valleys and the central/southern Appalachians...
   Two primary areas of convective activity are ongoing from MS/AL/TN
   border area northwest to the confluence of the MS/OH Rivers. Leading
   pre-frontal squall, low-topped near the central MS/AL border with
   progressively deeper tops northward, will likely persist
   east-northeast this afternoon and reach the southern Appalachians by
   early evening. With broken cloudiness across AL and richer
   boundary-layer moisture, sampled by the 12Z LIX sounding, advecting
   north from the central Gulf Coast, this QLCS should ingest the
   northern gradient of peak surface-based buoyancy. This should result
   in intensification of the squall line with embedded QLCS tornadoes
   and damaging winds as the primary hazards.

   Farther north, broken convective bands are evident along the
   northern periphery of the warm sector near the MS/OH Rivers
   confluence, close to the deep surface cyclone. A robust surface
   pressure rise-fall couplet and the extreme low to deep-layer shear
   should compensate for the meager surface-based buoyancy and likely
   yield a mix of low-topped supercells and quasi-linear bowing
   segments, as convection rapidly spreads east-northeast. Tornadoes
   should be realized in sustained supercells and line-embedded
   mesovortices, a few of which could be significant. Given the
   supercell wind profiles and morning CAMs suggesting more broken
   convection, damaging winds will probably consist of scattered swaths
   of severe gusts from 60-80 mph. 

   Severe potential today will be limited on the southern part by
   weakening DCVA and frontal convergence with southward extent, on the
   northern end by northward loss of boundary-layer destabilization
   away from the warm-frontal zone, and to the east by loss of both
   daytime heating and overall lift. As such, the unconditional
   probability gradient is kept rather broad on both sides, though the
   actual southern/northern/eastern cutoffs of severe could be abrupt.

   ..Grams/Wendt.. 03/03/2023

SPC MCD

Quote

   Mesoscale Discussion 0244
   NWS Storm Prediction Center Norman OK
   1015 AM CST Fri Mar 03 2023

   Areas affected...much of Kentucky...far southern Indiana...Middle
   Tennessee...northern Alabama

   Concerning...Tornado Watch 60...

   Valid 031615Z - 031915Z

   The severe weather threat for Tornado Watch 60 continues.

   SUMMARY...The threat for tornadoes will increase through the
   afternoon, from near the Ohio River southward into northern Alabama
   and eventually Georgia. Additional watches are likely later today
   east of ongoing tornado watch #60.

   DISCUSSION...A surface low near the IL/KY border will continue to
   deepen today as it travels up the OH River Valley and near a warm
   front. Areas of thunderstorms are ongoing near the low, with an
   arcing line of cells extending south into northern AL. Breaks in the
   clouds as well as strong southerly advection will continue to
   destabilize the warm sector, with sufficient instability forecast to
   support supercells with tornadoes by afternoon. 

   Limited instability near the warm front will be mitigated by very
   strong lift combined with cooling aloft, and these height falls will
   extend southward into Middle TN. Midlevel lapse rates will be
   steeper beneath the midlevel wave, with the surface low track and
   warm front zone being a favored area for tornadoes, some strong.
   Initial convection near the low has periodically shown signs of
   rotation.

   Ongoing storms from middle TN into northwest AL will continue to
   strengthen as well, aided by higher boundary-layer theta-e despite
   being south of the midlevel jet core. Very strong shear is in place
   across the entire region, favoring fast-moving supercells and
   tornado threat.

   ..Jewell/Grams.. 03/03/2023

 

[ak9971]

Latest HRRR run. A few soundings posted below as well. Some nasty cells right as the front moves through.

Cincy Metro

Approx. Louisville

Really interesting sounding out of Northern Georgia.

[DJKuo]

Here's my amateur satellite analysis.

  

[ak9971]

Absolute nasty wind gusts after the cold front moves through.

[Chinook]

oh yeah only 927 m2/s2 measured storm relative helicity here (similar value at Nashville radar)

Edited March 3, 2023 by Chinook

[Snow____]

39 minutes ago, ak9971 said:

New SPC discussion is out. Enhanced risk actually expands east some more. 30% hatched wind all the way into extreme western NC and Virginia now and still includes Cincy/Louisville for our area. They've added a hatched tornado area as well that coincides with their recent discussion that was just posted for additional tornado watches. Certainly seems that SPC thinks it will be an active day in our area although it certainly doesnt feel like it outside right now. Closer to our region they are still talking about some discrete activity but scattered 60-80mph gusts in storms that do form. I'll post HRRR in the next post to not make this one too cluttered.

SPC Latest Outlook

SPC MCD

 

I didn’t expect that seeing how the rain hasn’t moved out yet 

[Chinook]

maybe this could end up being a much larger tornado outbreak than yesterday

 

[ceciliaky]

18 minutes ago, DJKuo said:

Here's my amateur satellite analysis.

  

I am in the easternmost circle on the map (zip 42724, very near the Hardin Co mesonet station) ... it's rainy, the sky is bright, but it continues to get warmer. I'm actually at my house now after driving through nasty cold NKy, super rainy Louisville, and brightening sky I-65 corridor. 

At this point, I'm growing far more concerned about the backside winds. We've had 3" of rain this week and I've got some big pine trees just waiting to fall. Today might be that day. 

[ak9971]

2 minutes ago, Snow____ said:

I didn’t expect that seeing how the rain hasn’t moved out yet 

There is a very small window where rain lifts before the front gets here. Maybe 1-2 hours and CAPE getting into the 500 ball park in cincy metro. Color me skeptical. 

[ak9971]

Tornado warning just south of Paducah. Rotation really tightened up recently. 

[Chinook]

1 minute ago, ak9971 said:

Tornado warning just south of Paducah. Rotation really tightened up recently. 

At 1112 AM CST, a confirmed tornado was located just south of
Reidland, moving northeast at 55 mph.  This tornado will cross I-24 
near exit 11.