Severe Weather Threat - December 12-14, 2022

[CheeselandSkies]

Trey G.'s video forecast discussion from earlier today:



SPC considering the first watch for this event, for a smallish portion of western KS/OK and the TX panhandle. Some cells already firing off in that area, particularly near Sublette, KS.

Storm Prediction Center Mesoscale Discussion 2003

Severe weather, tornado, thunderstorm, fire weather, storm report, tornado watch, severe thunderstorm watch, mesoscale discussion, convective outlook products from the Storm Prediction Center.

www.spc.noaa.gov

Feels like watching an April setup in December...deja vu the last few years.

 

[CheeselandSkies]

Looks like we already had one tornado warning in the northern Texas panhandle, although it was cancelled early. Of course, the storm was/is almost exactly halfway between Amarillo and Dodge City radars, so hard to get a good look at the low levels.

 

[Taylor Campbell]

There are two tornado warnings now and from a distance they look healthy.

 

[TH2002]

Might be a tornado about to clip the west side of Gate, OK

 

[CheeselandSkies]

2.5" hail reported in Beaver County, OK with the western of the two potentially tornadic cells.

 

[buckeye05]

Looks like there may have a CC drop near Beaver earlier? I’m not totally sure.

 

[TornadoFan]

Storm near Sitka, KS is getting it's act together.

 

[buckeye05]

Storm near Sitka, KS is getting it's act together.

 

[OHWX97]

Another long duration severe weather event continues to be likely for the southeast later today, continuing Wednesday, and possibly into Thursday.

Day 1 Outlook (12/13)

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
1156 PM CST Mon Dec 12 2022

Valid 131200Z - 141200Z

...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS
OF EASTERN TEXAS...LOUISIANA...AND INTO THE LOWER MISSISSIPPI RIVER
VALLEY...

...SUMMARY...
Severe thunderstorms capable of all severe hazards including
tornadoes, some strong, are possible from parts of east Texas to the
Lower Mississippi Valley area today and tonight.

...Synopsis...
An anomalously deep upper-level cyclone centered over the Plains
states is forecast to shift slowly eastward today and tonight while
90-100+ kt of mid-level flow overspreads the Mississippi River
Valley and Gulf Coast. A sub 1000 mb surface low across northern KS
and southern NE will continue to advect a partially modified Gulf
airmass inland ahead of a fast moving cold front. Rapid
destabilization and strong vertical shear beneath a 50+ kt 850 mb
jet will support a risk for all severe hazards over a wide area from
early this morning through the overnight hours.

...ArkLaTex into the Lower MS River Valley...
As the main frontal band continues east through the early afternoon,
strong low-level warm advection is expected ahead of it as a warm
front lifts north through southeastern OK and into central AR. To
the south, low to mid 60s F surface dewpoints will stream northward
reaching the AR/LA border by 21z. Dense stratus cover in the warm
advection region will likely forestall surface heating, but the
combination of surface moistening and cooling aloft should result in
more favorable thermodynamics with time. As the low-level jet shifts
eastward through the afternoon and evening low-level hodographs
should expand favorably for supercells capable of all severe
hazards.

Storm mode remains somewhat uncertain with weak capping and strong
warm advection taking place ahead of the frontal band. HREF guidance
suggests the squall line may reorganize into more semi-discrete
elements with additional development possible ahead in the warm
sector with time as better thermodynamics are realized. 0-1km shear
values in excess of 35 kt will be strongly supportive of low-level
updraft rotation and some strong tornado risk may evolve if
semi-discrete supercells are able to develop. Otherwise, embedded
circulations capable of strong winds and tornadoes are expected.

The northern extent of the severe risk also remains unclear and tied
to destabilization with advection of the richer boundary-layer
moisture. Faster model solutions suggest storms may remain severe
across portions of northern MS into early Wednesday morning. While
thermodynamics are likely to be marginal, very strong low and
mid-level shear profiles will support a mix of supercells and short
line segments capable of damaging gusts.

Farther south across southeastern LA and southwest MS, continued
onshore advection of the moist and unstable Gulf airmass will likely
keep the severe risk ongoing through the night. Large and mostly
streamwise low-level hodographs (0-500m SRH 200+ m2/s2) will favor
supercells and a risk for nocturnal tornadoes.

..Lyons/Kerr.. 12/13/2022

Day 2 Outlook (12/14)

Day 2 Convective Outlook
NWS Storm Prediction Center Norman OK
0100 AM CST Tue Dec 13 2022

Valid 141200Z - 151200Z

...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS MUCH OF
SOUTHERN LOUISIANA...MISSISSIPPI...WESTERN AND SOUTHERN ALABAMA AND
THE WESTERN FLORIDA PANHANDLE...

...SUMMARY...
Tornadoes and damaging winds are expected Wednesday over parts of
southern Louisiana, Mississippi, southwest Alabama and the western
Florida Panhandle. A few strong tornadoes may occur.

...Synopsis...
An upper low will drift eastward across SD/NE/IA with a large upper
trough pivoting from the Plains into the MS Valley. A leading speed
max will extend roughly from the middle MS Valley southwestward into
southern TX by 00Z with 500 mb speeds over 100 kt. Strong midlevel
southwesterlies of 50-70 kt will extend over a large part of the
Southeast ahead of this trough, with 850 mb winds around 50 kt out
of the south aiding moisture advection.

At the surface, the main low will be near the SD/NE/IA area for much
of the day, with a trough/cold front crossing the MS River.
Meanwhile, a warm front will extend roughly from western TN/northern
MS to the FL Panhandle at 12Z Wed, lifting northward across much of
MS and AL through 00Z. Dewpoints in the upper 60s F will be common
across the warm sector, resulting in favorable MLCAPE for severe
storms given strong shear and increasing large-scale ascent.

...Southern LA into MS, AL and the western FL Panhandle...
Several models indicate scattered storms may be ongoing Wednesday
morning along an outflow boundary across parts of MS and LA. These
storms will approach a plume of mid 60s F dewpoints, aided by a 40+
kt low-level jet. Instability will be sufficient to support
supercells with a tornado risk as the outflow should decelerate. A
warm front will exist roughly from northern MS into southwest AL,
providing a limit to SBCAPE early in the day. These storms may tend
to wane by midday as low-level winds diurnally adjust.

It appears the primary severe risk will develop during the afternoon
and evening as large-scale lift increases along and ahead of the
cold front. Predictability for outflow-boundary position is low at
this time. However, southern parts of LA, MS, and AL have a high
probability of destabilization ahead of the cold front which will
approach from the west. At the very least, a broken line of
supercells is expected along this front, with a substantial
cross-boundary component to the deep-layer shear. Effective SRH
averaging 200-300 m2/s2, mid to upper 60s F dewpoints and MLCAPE
over 1000 J/kg will favor a risk of tornadoes. Models also indicate
possible mesolows along the line, with locally strong storm-relative
inflow/backed surface winds likely as the convection matures late in
the day.

Should a southwest-northeast oriented outflow boundary remain in
place during the afternoon ahead of the cold front, it could provide
a favored corridor for strong tornadoes, enhancing low-level ascent
and shear. While coverage of severe storms may decrease somewhat
overnight, additional activity may develop toward 09-12Z Thursday
across the FL Panhandle and southwest GA, where both instability and
shear (of similar magnitude to western areas) will remain favorable
for tornadic supercells.

..Jewell.. 12/13/2022

Day 3 Outlook (12/15)

Day 3 Convective Outlook
NWS Storm Prediction Center Norman OK
0214 AM CST Tue Dec 13 2022

Valid 151200Z - 161200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS OVER PARTS OF
FLORIDA...SOUTHERN GEORGIA AND SOUTH CAROLINA...

...SUMMARY...
A few severe storms will be possible over parts of the Southeast
mainly early on Thursday.

...Discussion...
An upper low will continue to deepen over the upper MS valley on
Thursday, with an expansive area of cyclonic flow aloft covering the
majority of the CONUS. A leading wave over the Appalachians is
forecast to weaken as it moves toward the Mid Atlantic, with an
associated surface low moving from GA into the Carolinas. A cold
front will trail south from this low, into the Gulf of Mexico.

Storms will likely be ongoing along the cold front from GA into the
eastern Gulf of Mexico early on Thursday, with upper 60s to near 70
F dewpoints along the FL portion of the front. Although low-level
winds will veer with time due to the passage of the upper wave,
deep-layer shear of 40-50 kt will exist from FL into southern GA,
and SRH will be near 300 m2/s2 early in the day. As such, a few
supercells will be possible with the initial activity, and a tornado
cannot be ruled out across northern FL including the Panhandle, as
well as southern GA. Other storms may approach the western coast of
FL, with a few damaging gusts possible. Otherwise, large-scale lift
will gradually decrease, and little additional activity is expected
aside from that which evolves from the ongoing early day storms.

..Jewell.. 12/13/2022

 

[OHWX97]

A couple of small supercells, one approaching Wichita Falls, Texas, and another just to its south, passing over Throckmorton, are showing signs of rotation. Might produce tornadoes if they continue getting their act together.

 

[OHWX97]

Tornado warning has just been issued for the southern of those two cells, near Archer City, TX. Additional cells further south are also showing signs of rotation.

 

[keithGA]

Big CC drop near Wayne, OK.

 

[SmokeEater]

The ones headed for the metroplex right at rush hour are very concerning....

Sent from my SM-S901U using Tapatalk

 

[keithGA]

HRRR sounding west of DFW.

 

[Sawmaster]

Found some vids from yesterday



WFAA covered a confirmed tornado in Eastland/Erath TX counties at 6:15AM local time WFAA
KOCO shows one house damaged in Wayne OK KOCO

 

[Bevo]

Not a great look for DFW Metroplex rush hour crowd...south Decatur storm has a TDS according to Texas Storm Chasers Livestream.

 

[atrainguy]

Found some vids from yesterday



WFAA covered a confirmed tornado in Eastland/Erath TX counties at 6:15AM local time WFAA
KOCO shows one house damaged in Wayne OK KOCO

Looks like the top video in McLean is footage from 2017 according to the description.

 

[Sawmaster]

Looks like the top video in McLean is footage from 2017 according to the description.

OOps- will delete that. Was short on caffeine when I did the search. Thanks!

 

[CheeselandSkies]

Looks like a possible tightening of circulation over White Settlement headed toward River Oaks.

Edit: Tornado warned as I was making the post.

 

[CheeselandSkies]

Annnnnnd radar confirmed.