Severe WX March 23-25th, 2023

[UncleJuJu98]

If the outflow boundary pushes further south it could become a real issue, it may be too far north to really help in enhancing a tornado or supercell. It's nudged a bit more south in the last satellite imagery though. The surface low is starting the process of cyclogenesis.

Seems like it's almost draped along the Arkansas Louisiana border into far north Mississippi. Which is getting close to the point where I would really worry.

 

[UncleJuJu98]

Current pressure analysis; cyclogenesis is in process. Winds should be picking up in Mississippi shifting to a more backed low level angle to feed into the deepening low.

 

[UncleJuJu98]

A new watch is needed very soon, initiation is about to start

 

[CheeselandSkies]

BULLETIN - EAS ACTIVATION REQUESTED
Tornado Warning
National Weather Service Shreveport LA
247 PM CDT Fri Mar 24 2023

The National Weather Service in Shreveport has issued a

* Tornado Warning for...
Central Little River County in southwestern Arkansas...
Central Hempstead County in southwestern Arkansas...
Southeastern Sevier County in southwestern Arkansas...
Southeastern Howard County in southwestern Arkansas...

* Until 330 PM CDT.

* At 247 PM CDT, a severe thunderstorm capable of producing a tornado
was located just west of Ashdown, moving east northeast at 50 mph.

HAZARD...Tornado.

SOURCE...Radar indicated rotation.

IMPACT...Flying debris will be dangerous to those caught without
shelter. Mobile homes will be damaged or destroyed.
Damage to roofs, windows, and vehicles will occur. Tree
damage is likely.

* This dangerous storm will be near...
Ashdown and Wilton around 250 PM CDT.
Saratoga around 305 PM CDT.
Mineral Springs and Tollette around 310 PM CDT.
Washington around 325 PM CDT.

Other locations impacted by this tornadic thunderstorm include Bright
Star, Browntown, Millwood, McCaskill, Ozan and Oakhaven.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

TAKE COVER NOW! Move to a basement or an interior room on the lowest
floor of a sturdy building. Avoid windows. If you are outdoors, in a
mobile home, or in a vehicle, move to the closest substantial shelter
and protect yourself from flying debris.

Heavy rainfall may hide this tornado. Do not wait to see or hear the
tornado. TAKE COVER NOW!

&&

LAT...LON 3398 9366 3375 9353 3360 9422 3372 9427
3400 9371
TIME...MOT...LOC 1947Z 247DEG 42KT 3368 9418

TORNADO...RADAR INDICATED
MAX HAIL SIZE...<.75 IN

$$

 

[UncleJuJu98]

Rather tight couplet I'm a weaker meso

 

[tornado examiner]

Shear is already producing rotations and the main event hasn’t begun yet…

 

[UncleJuJu98]

Tight rotation dissipated still a weak meso but it's broad.

 

[Shakespeare 2016]

This feels like wishful thinking to me. We're still a ways out in that area. But I'll look for any reason for optimism and hope they're on to something.

There have been instances of this on many occasions. The temperature will warm into the low/mid 70s to around the low 80s and have dewpoints in the low 60s in the afternoon. Then in the early to late evening temperatures start to drop and dewpoints start to rise. Like for instance it my be 80F with a dewpoint of 62F in the afternoon but by mid late evening temperatures drop into the upper 60s to low 70s and dewpoints will rise into the mid to upper 60s. Like 74/69. Correct me if I am wrong but also doesn't LCL'S drop as the temperature and dewpoint get closer to each other.

 

[OHWX97]

Tight rotation dissipated still a weak meso but it's broad.

I'm getting concerned that storm, or the one just to its southwest, might try and ride that outflow boundary.

 

[Equus]

Moderate remains, but enhanced expanded east a bit

 

[UK_EF4]

They stayed moderate. Not much of a surprise given upgrades at 20z are very rare, but potential for a very high end event still exists. April 12th 2020 and December 10th 2021 were both moderate days (not to suggest we will get something like that though)

 

[UncleJuJu98]

19z hrrr doesn't look as bad as the 18z. Oh well. It's pretty much game time.

 

[Smokedevil]

Some cells starting to pop near natchez ms.

 

[ColdFront]

I'm getting concerned that storm, or the one just to its southwest, might try and ride that outflow boundary.

A good visual example of what a thermal/outflow boundary can do for a cell/tornado:

Look at the Cullman tornado on 4/27. While it was a strong tornado while in Cullman, it was pretty thin and stove pipe looking on the tower cam.

Now go watch a video of it after it crossed the boundary and it’s going through Arab. Just a massive wedge with the LCLs scraping the ground.

@Equus linked an extremely interesting research paper on the thermal boundary from 4/27 that was a great read.

 

[UncleJuJu98]

Tornado warning near ashdown is going to be a problem soon. Continuous strengthing of the meso

 

[TheSuckZone]

...20Z Update...
No changes have been made to the Moderate Risk area. Convection is
beginning to increase in coverage and intensity ahead of the cold
across far east TX, in addition to the ongoing activity along the
front itself. As a southerly low-level jet strengthens late this
afternoon into this evening, a corresponding increase in effective
SRH will likely lead to greater tornado potential with time. The
greatest threat for strong tornadoes remains apparent this evening
across parts of northern LA into southern/eastern AR,
northern/central MS, and western/middle TN. This will especially be
the case with any supercells that can remain discrete ahead of the
line.

A bowing line/MCS will likely develop this evening as convection
grows upscale along/ahead of the front. The northern extent of
appreciable severe threat will likely be constrained by a
convectively reinforced outflow boundary from thunderstorms earlier
today that currently extends from parts of AR into TN. This boundary
will attempt to lift back northward this evening and overnight as a
surface low deepens from the Mid-South into the lower OH Valley.
Still, the threat for damaging winds and tornadoes should become
increasingly limited with northward extent into KY and the OH
Valley.

The primary change with this update was to expand severe wind
probabilities and corresponding categorical lines a bit eastward
across AL/TN, north GA, and western NC/SC. Recent high-resolution
guidance, including multiple runs of the HRRR, suggest that a
well-organized bow will continue eastward across these areas late
tonight into early Saturday morning. Although instability is
forecast to remain weak, very strong low-level shear associated with
a 55-65+ kt low-level jet should allow the line to remain organized
and pose a continued threat for severe/damaging winds and a few
embedded QLCS tornadoes.

 

[ColdFront]

19z hrrr doesn't look as bad as the 18z. Oh well. It's pretty much game time.

Yeah at this point I’ve thrown out the models haha

 

[Equus]

There have been instances of this on many occasions. The temperature will warm into the low/mid 70s to around the low 80s and have dewpoints in the low 60s in the afternoon. Then in the early to late evening temperatures start to drop and dewpoints start to rise. Like for instance it my be 80F with a dewpoint of 62F in the afternoon but by mid late evening temperatures drop into the upper 60s to low 70s and dewpoints will rise into the mid to upper 60s. Like 74/69. Correct me if I am wrong but also doesn't LCL'S drop as the temperature and dewpoint get closer to each other.

Yep, LCLs will drop as the higher dews arrive and the surface temperature cools a little, should become a more favorable environment with the low level jet

 

[OHWX97]

Great twitter thread from SPC forecaster, Andrew Lyons, highlighting the QLCS threat further to the north.

 

[TornadoFan]

Ashdown meso fell apart, I think.