Severe WX December 10 & 11, 2021 Severe Threat

[tennessee storm chaser]

Know time the fv3 short range model is over done sometime . But wow at the super cell picking up crossing ms river into nw Tennessee. That would be a long tracker for sure n border violent tornado

 

[Taylor Campbell]

Does anyone know if Little Rock is doing a special weather balloon sounding? I wish they would.

 

[chasestormz39]

So uhh, that 16z HRRR is probably nudging towards high risk material.

Would love to hear your thoughts on how far north you see the tornado threat evolving in IL.

 

[andyhb]

Would love to hear your thoughts on how far north you see the tornado threat evolving in IL.

Think I-70 is a good starting point for the most significant threat, although risk for isolated tornadoes probably extends towards I-80 and the LOT CWA.

 

[WesL]

The forcing that appears to be the focal point for supercell development later this afternoon and evening across northeast AR is just about to cross the southeast OK/southwest AR border.

Great.......

 

[Taylor Campbell]

17z HRRR shows mean long track updraft helicity streaks between interstate 40 and highway 67 in AR tracking northeast. That would bring significant tornado risk very close to Jonesboro, AR.

 

[CheeselandSkies]

Think I-70 is a good starting point for the most significant threat, although risk for isolated tornadoes probably extends towards I-80 and the LOT CWA.

This is why I hate December threats. I should be getting my car prepped for winter driving, and getting my Christmas shopping done...and here I am thinking about getting it prepped for a storm chase!

 

[SilentShadow87]

This is why I hate December threats. I should be getting my car prepped for winter driving, and getting my Christmas shopping done...and here I am thinking about getting it prepped for a storm chase!

We Canadians have had our snow tires on for weeks now, get with the program lol.

 

[CheeselandSkies]

I don't really believe I will be chasing this...the I-72 corridor in IL is a 4-hour drive each way for me, for what will surely be a nocturnal event.

One takeaway from the HRRR is that we will be getting a lot of rain here...which we need.

 

[Kory]

Smashing record highs in MS and West TN.

 

[warneagle]

Yeah I think it's safe to say the models have been undercooking the thermos on this one. Yikes.

 

[chasestormz39]

Think I-70 is a good starting point for the most significant threat, although risk for isolated tornadoes probably extends towards I-80 and the LOT CWA.

18z HRRR certainly is interesting along the I74 corridor

 

[CheeselandSkies]

20Z maintains smallish moderate. A bit surprising since in some respects 18Z was the nastiest HRRR run yet.

 

[cincywx]

Valid 101935Z - 102145Z

CORRECTED FOR TYPO

Probability of Watch Issuance...95 percent

SUMMARY...Discrete supercell development appears increasingly
probable by 4-6 PM CST, accompanied by the risk for severe hail and
tornadoes, including increasing potential for a couple of strong
tornadoes by early evening.

DISCUSSION...A short wave impulse of subtropical eastern Pacific
origin continues to accelerate northeastward across Kansas and
Oklahoma, and is forecast to reach the mid/lower Missouri Valley
vicinity by early evening. Mid/upper forcing for ascent and
elevated moisture return preceding this feature have contribute to
weak high-based convection and light rain in a corridor across
eastern Oklahoma into the lower Missouri Valley, while low-level
moisture from the Gulf of Mexico gradually deepens across the lower
Mississippi Valley into parts of the southeastern Great Plains. The
deeper low-level moisture return is being aided by a branch of
stronger southerly flow across the northwestern Gulf coast vicinity
into the Ozark Plateau. This appears to include a 40-45 kt speed
maximum around 850 mb, across the upper Texas coastal plain into the
Ark-La-Tex vicinity.

Through 21-00Z, model output continues to generally indicate that
this speed maximum will rapidly propagate northeastward into the
Ozark Plateau through middle Mississippi/lower Ohio Valley vicinity,
while strengthening to 50+ kt in a corridor from near Little Rock AR
into the Missouri Bootheel vicinity. It appears that deepening
boundary-layer moisture and increasing mixed-layer CAPE along this
corridor will coincide with weakening inhibition associated with a
transition from broadly anticyclonic to cyclonic mid-level flow.
This is expected to allow for the initiation of at least scattered
discrete storm development, as southwesterly flow in the 700-500 mb
layer also strengthens to 60-80+ kt.

This regime likely will become increasingly conducive to the
development of supercells, with the potential to produce severe hail
initially, along with at least some risk for tornadoes. Backing of
surface winds toward a south to south-southeasterly component by 00Z
may gradually contribute to enlarging, clockwise-curved low-level
hodographs increasingly conducive to tornadoes, a couple of which
may become strong.

gonna be some fast movers on this one

 

[Austin Dawg]

Yeah I think it's safe to say the models have been undercooking the thermos on this one. Yikes.

I'm not an expert but I have to agree. Usually in a big tornado event east of us it is extremely warm followed by strong winds and dry, cool air.

High today - 85 Low tonight 49 with winds around 20 mph and gusts nearing 40. Low Sat night 32... 53 degree temp swing.

 

[CheeselandSkies]

18Z HRRR with a pretty strong signal for a bimodal threat favoring parts of central/"southern northern" IL and then a large gap of nothing before some more nastiness tracking from NE AR/the MO bootheel into western KY/TN/far southern IL.

 

[tennessee storm chaser]

I’m seeing some pds soundings In some areas U spoke of particular ne ark nw Tennessee western Kentucky

 

[chasestormz39]

18Z HRRR with a pretty strong signal for a bimodal threat favoring parts of central/"southern northern" IL and then a large gap of nothing before some more nastiness tracking from NE AR/the MO bootheel into western KY/TN/far southern IL.

The cells down in the bootheel through S IL, W KY and TN have the potential to do some bad things. I assume the storms up north will carry a tornado threat along with damaging winds but probably not quite at the level of what will happen further south. Nonetheless, with fast storm motions, hope everyone is heeding warnings tonight.

 

[JPWX]

74 degrees, humidity 90.7, and dewpoint 71.1 here in Smithville, MS.

 

[tennessee storm chaser]

We going set up starting at area between dyersburg to Jonesboro , then go from there …