April 11-13, 2022 | Tornado Outbreak

[Chinook]

2 hours ago, ClicheVortex2014 said:

HRRR has a bit of a rough Monday evening for central AR

I would say that the slight risk for Monday will be mainly a threat for Arkansas. Tuesday: capping will be a big issue, but I think some storms will go. Maybe some storms in or near Nebraska with the low pressure center, and some storms farther south. Wednesday, a larger event may be possible due to the fact that the cap will be broken at the cold front.

[StormfanaticInd]

Day 4-8 Convective Outlook  

   NWS Storm Prediction Center Norman OK

   0400 AM CDT Sun Apr 10 2022

 

   Valid 131200Z - 181200Z

 

   ...DISCUSSION...

   A substantial severe threat will continue on Day 4/Wednesday across

   parts of the central/eastern CONUS. Large hail, damaging winds, and

   tornadoes should occur.

 

   ...Day 4/Wednesday: East Texas/Oklahoma into the Mississippi

   Valley/Midwest and Southeast...

   The large-scale upper trough over the Plains Wednesday morning

   should eject across the MS Valley, Midwest, and Great Lakes through

   the Day 4/Wednesday period. Differences remain in the details with

   the placement and evolution of the upper low/trough. Even so, a cold

   front attendant to a deep surface cyclone over the Upper Midwest

   will sweep eastward across much of the lower/mid MS Valley and

   Midwest Wednesday afternoon through Wednesday night. Strong

   low-level and deep-layer shear will accompany this frontal passage,

   which will likely support a substantial organized severe

   thunderstorm threat. It appears probable that rich low-level

   moisture characterized by mid to upper 60s surface dewpoints will

   advance as far northward as parts of the mid MS Valley/lower OH

   Valley. Sufficient instability should be present ahead of the cold

   front to support surface-based thunderstorms.

 

   Convection may be ongoing Wednesday morning over parts of the

   Mid-South aided by strong low-level warm advection. Additional

   scattered to numerous thunderstorms are expected to develop

   along/ahead of the eastward-moving cold front. If some of this

   convection can form ahead of the front, deep-layer shear would be

   strong enough to support supercells. A more linear mode should also

   develop along the front itself. All severe hazards, including large

   hail, damaging winds, and tornadoes should occur as this convection

   sweeps eastward across the lower/mid MS Valley, Midwest, and parts

   of the Southeast through Wednesday night. The 15% severe area has

   been expanded eastward based on the consensus of latest model

   guidance suggesting sufficient low-level moisture will be in place

   over more of the Midwest, TN Valley, and Southeast Wednesday

   evening/night to support surface-based thunderstorms. The 30% severe

   area was extended northward and eastward into more of the lower/mid

   MS Valley where confidence is greatest in scattered to numerous

   discrete and linear convection Wednesday afternoon. 

[voltwaffle]

Every time I look, it's farther west.

[Iceresistance]

Goodness! That's over Wichita, KS on the 0z GFS

[Iceresistance]

This Enhanced risk is HUGE! One of the largest I've ever seen

[FortySixAnd32]

ILN early thoughts:

 

Confidence remains high in a more active pattern evolution for the middle of the workweek as the overall flow amplifies, with a deep trough over the central plains and ridging centered toward the Carolinas. After stalling/washing out on Tuesday, whats left of any broad/ill-defined baroclinic zone will move N of the OH Vly by Tuesday night into early Wednesday. Deep-layer SSW flow will become established during this time period, with am embedded S/W expected to move through the western OH/TN Vlys Wednesday morning into the afternoon. This will initiate another round of SHRA, with some embedded TS, during the daytime on Wednesday, especially across western parts of the ILN FA. Later in the day/evening, attention will turn to the cold front moving into the area from the west. At this juncture, expect a well- defined front to move into the local area Wednesday night, attached to a surface low that will likely be occluding as it moves into the Upper Midwest Wednesday night. Timing differences are still notable with the frontal passage, but the main impacts locally seem likely to occur in the Wednesday night / early Thursday time frame. Depending on frontal timing and the degree of moisture advection, some threat of strong storms could exist, but this is still too far out to suggest any clarity in the specifics of this potential. As with other systems so far this spring, instby will likely be a limiting factor. It should also be noted that gusty winds are likely with this system, in the warm sector on Wednesday and Wednesday night, possibly with the frontal passage, and then with the WSW flow behind the front on Thursday. Will keep this all in the 26-30 kt range for now, but could see some potential for slightly higher gusts than that should the mixing become more optimal at any point during this time frame.

[Iceresistance]

Storm Shelter is ready

[ClicheVortex2014]

7 hours ago, Chinook said:

I would say that the slight risk for Monday will be mainly a threat for Arkansas. Tuesday: capping will be a big issue, but I think some storms will go. Maybe some storms in or near Nebraska with the low pressure center, and some storms farther south. Wednesday, a larger event may be possible due to the fact that the cap will be broken at the cold front.

The way I see it... Tuesday has the greatest potential (magnitude)... Wednesday is lower but more widespread. A quick transition to a squall along the cold front is a good bet with a low this strong.

Edited April 10, 2022 by ClicheVortex2014

[Iceresistance]

Reed Timmer is a good storm chaser, but Pecos Hank is also going to be there as well

 

[ElectricStorm]

Just now, Iceresistance said:

Reed Timmer is a good storm chaser, but Pecos Hank is also going to be there as well

 

Reed gets great footage bit he can be super annoying when he yells all the time. I like how Pecos Hank always remains calm

[Iceresistance]

1 minute ago, OKwx_2001 said:

Reed gets great footage bit he can be super annoying when he yells all the time. I like how Pecos Hank always remains calm

Pecos Hank apparently has more followers than Reed Timmer because they really like how clam Pecos Hank is, no matter the situation.

 

Let's not get too OT here

Edited April 10, 2022 by Iceresistance

[Iceresistance]

He's from Owasso, OK

The FV3 Hi-Res now breaks the cap

 

[Iceresistance]

Local TV Met for KFOR

 

[Central Illinois]

Looks like we might be in for quite the event on Wednesday 

[Central Illinois]

ILX

Very strong low pressure lifts into the upper MS river valley by sunset Wed while pushing a cold front east through IL Wed afternoon. Still some timing differences with the front as GFS is quicker than ECMWF and GEM models. But very strong wind fields and more instability to support risk of severe storms over area with a QLCS line of storms likely racing eastward over IL on Wed. SPC day4 outlook has 15-30% risk of severe storms over IL, with the 30% risk from Shelbyville to Robinson south where heavy rains may also occur. Tornadoes, large hail and damaging winds will be threats over the area Wed especially Wed afternoon.

[ClicheVortex2014]

NAM seems to be exaggerating things on Wednesday but CIPS analogs have liked the mid-MS valley. 0-6km shear vector is fairly favorable across the cold front in the area. It's got the best shear, too.

[ClicheVortex2014]

18z NAM has a pre-frontal band of storms. Definitely would need watched. Appears to be forced by surface wind convergence/pre-frontal trough(?)

[ClicheVortex2014]

ICT says storms may have trouble organizing until the mid-level support arrives... but when that does happen, the orientation of the deep layer shear vector with respect to the boundary is unfavorable for cells to stay discrete for very long.

Sounds like some serious bust potential at least for tornadoes.

East of the dry line, moisture advection will continue and likely
drive Tds into the upper 50s and low 60s provided the needed fuel
for the development of thunderstorm activity.  Lapse rates through
the first 25Kft (6Km) are very good with most model soundings
averaging in the 7-8.5 C/Km range.  Shear through the first 10Kft
(3Km) is good with very good turning and winds in the 50-60Kt range.
Mid level shear (up to 25Kft or 6Km) is more problematic.  Wind
speeds drop off into the 40-55kt range but the directional shear is
complimentary.  This shear profile will allow for the development of
strong to severe thunderstorms however, with the drop in mid level
wind speeds, some storms may struggle to fully develop until the
main jet stream support arrives later in the day. Given the lapse
rates, complimentary CAPE values and decent shear, all threats
appear to be on the table upon initiation.  Tornadic activity does
appear to be a good possibility while storms remain discrete.  The
main fly in the ointment is the arrival of the upper level jet
stream support.  All the ensemble models show the main jet support
arriving later in the afternoon and into the evening but in a more
north to south orientation.  This orientation is not conducive to
wide spread tornadic development but more to a squall line scenario
with hail and wind being the primary threat.  The models are
beginning to cluster around this solution and confidence is
increasing that the main threat will be wind and hail.  It is
important to note the tornado threat can`t be ruled out, especially
in the beginning while storms are still in the discrete storm mode.
At this point in time, model solutions are clustering around an
increasing chance for severe weather with all threats possible to
start with the tornado threat decreasing as the evening progresses.

 

Edited April 10, 2022 by ClicheVortex2014

[Iceresistance]

NWS-Norman radar has the Boundary mostly stalled already, could there be storms further north than expected?

[Ingyball]

15 minutes ago, ClicheVortex2014 said:

ICT says storms may have trouble organizing until the mid-level support arrives... but when that does happen, the orientation of the deep layer shear vector with respect to the boundary is unfavorable for cells to stay discrete for very long.

Sounds like some serious bust potential at least for tornadoes.

East of the dry line, moisture advection will continue and likely
drive Tds into the upper 50s and low 60s provided the needed fuel
for the development of thunderstorm activity.  Lapse rates through
the first 25Kft (6Km) are very good with most model soundings
averaging in the 7-8.5 C/Km range.  Shear through the first 10Kft
(3Km) is good with very good turning and winds in the 50-60Kt range.
Mid level shear (up to 25Kft or 6Km) is more problematic.  Wind
speeds drop off into the 40-55kt range but the directional shear is
complimentary.  This shear profile will allow for the development of
strong to severe thunderstorms however, with the drop in mid level
wind speeds, some storms may struggle to fully develop until the
main jet stream support arrives later in the day. Given the lapse
rates, complimentary CAPE values and decent shear, all threats
appear to be on the table upon initiation.  Tornadic activity does
appear to be a good possibility while storms remain discrete.  The
main fly in the ointment is the arrival of the upper level jet
stream support.  All the ensemble models show the main jet support
arriving later in the afternoon and into the evening but in a more
north to south orientation.  This orientation is not conducive to
wide spread tornadic development but more to a squall line scenario
with hail and wind being the primary threat.  The models are
beginning to cluster around this solution and confidence is
increasing that the main threat will be wind and hail.  It is
important to note the tornado threat can`t be ruled out, especially
in the beginning while storms are still in the discrete storm mode.
At this point in time, model solutions are clustering around an
increasing chance for severe weather with all threats possible to
start with the tornado threat decreasing as the evening progresses.

 

 

I've mentioned before but I do believe this is very heavily relied on the cap holding (which it very well could). Ensembles don't back winds at 500 and 300mb until 6z where linear mode would be favorable. The FV3 run at least looked semi-discrete and that's kind of what I'm expecting (if not discrete) if the cap breaks because that's kind of the nature of strongly capped environments. I've had my suspicions that the cap will break somewhere, it's hard for it not to when you have a sub 990mb surface low close to the warm sector. Anyways, NAM has about 45-50kts of effective shear, which would be plenty to support supercell growth. 

[Iceresistance]

Cameron's page has been upgraded!
 

 

[ClicheVortex2014]

Fun synoptic map. Outside of the obvious... influence from the system reaches from Idaho to Ohio. Easily half the country.

[ClicheVortex2014]

AFDs from PAH, MEG, and JAN respectively

.LONG TERM...(Wednesday through Sunday)
Issued at 259 PM CDT Sun Apr 10 2022

A potentially active day of severe weather is possible on
Wednesday. Another surface low pressure will organize east of the
Rocky Mountains and race to the northeast, deepening rapidly. A
trailing cold front will move through the central and southern
Plains and eventually into the PAH CWA during the afternoon and
evening hours. Very strong S-SW 850-700 mb winds will promote
elongated hodographs along with sufficient surface-based
instability ahead of the front. Strong WAA will continue to pump
dew points into the lower to middle 60s into the region. A
prefrontal trough could bring scattered showers and non-severe
thunderstorms to the region Wednesday morning. However, the severe
risk will ramp up in the afternoon and evening hours as the cold
front approached. The storm mode looks to a mix of discrete and
linear elements, with all hazards possible (i.e. damaging wind,
large hail, and a few tornadoes). The SPC Day 4 outlook has
already placed nearly all the CWA under an enhanced risk, and we
see no reason to deviate from that messaging.

 

The front will lift back north as a warm front Tuesday morning.
Expect much of Tuesday to be dry with the exception of a few
isolated warm air advection showers. Temperatures should climb
into the upper 70s to lower 80s for highs. This will produce a
warm, moist, and unstable air mass across the Mid-South just in
time for the next round of severe weather which is expected
Tuesday evening into the overnight hours on Wednesday. Models are
showing thunderstorms developing across Southern Arkansas as a
shortwave trough moves into the region. The convection will then
lift northeastward into the Midsouth and eventually into the Ohio
Valley by Wednesday morning. All modes of severe weather will be
possible with this round as well as Heavy rain which could lead to
flash flooding.

Questions still remain about round 3 of severe weather which is
expected to occur late Wednesday afternoon into Wednesday Night.
It will depend on if there is any lingering morning convection
and how quickly it clears? If the convection hangs on too long
then the atmosphere may not have time to recover in time for the
next round of severe weather. However, if the atmosphere can
indeed recover then there will be possibility of severe weather as
a potent negatively upper trof will be moving through the Upper
Midwest as the associated trailing cold front moves into the Mid-
South late Wednesday afternoon into Wednesday Night. Supercell
development out ahead of the front in addition to a QLCS along the
front will be possible with the front as dewpoints climb into the
mid to upper 60s ahead of the approaching front. CAPE values will
likely be around 1500 J/KG and will be combined with 0-1 km SRH
of greater than 300 M2/S2. Thus if this airmass is in place then
tornadoes, damaging wind and large hail will be possible with any
severe storms. Flash flooding may also occur especially in
locations that receive heavy rain Tuesday Night into Wednesday.

 

Better potential for severe weather will exist Tuesday afternoon and
evening in the western parts of the forecast area and then again on
Wednesday afternoon and evening for much of the entire area. On
Tuesday, a subtle disturbance in the southwest flow aloft will move
across the region. This will combine with steep lapse rates (27-28C
vertical totals), sufficient shear, peak daytime heating and
instability to bring potential for organized severe weather on
Tuesday. Will continue to mention this slight and marginal risk in
the HWO/graphics.

The next and possibly better potential for severe weather will come
on Wednesday. As the upper trough to our west takes on a bit more of
a negative tilt as it swings in our direction, and a 986-991mb
surface low will track up to the Ohio Valley region. This will drag
a front down toward the Lower Mississippi River Valley region. The
atmosphere ahead of this will be primed for severe weather with
steep lapse rates (28-30C Vertical totals), sufficient shear that
will be enough to result in organized severe weather, 1900-3000 J/kg
of MUCAPE (and nearing 3300 J/kg of SBCAPE), and 100-300 m2/s2
helicity values. All this being said, all modes of severe weather
will be possible with damaging winds, large hail of golfball
size(maybe higher if discrete cells can develop), and tornadoes.
Will continue to advertise the enhanced and slight risks in the
graphics for Wednesday afternoon and evening.

 

Edited April 11, 2022 by ClicheVortex2014

[Iceresistance]

11 minutes ago, ClicheVortex2014 said:

Fun synoptic map. Outside of the obvious... influence from the system reaches from Idaho to Ohio. Easily half the country.

The WPC thinks that the Cap will break over Oklahoma

[ClicheVortex2014]

11 minutes ago, Iceresistance said:

The WPC thinks that the Cap will break over Oklahoma

I wouldn't read too much into that. They're more focused on the big picture... they probably didn't spend too much time on the mesoscale.

0z suite has begun with HRRR. I'll be surprised if HRRR kicks off any convection through Tuesday. It loves to overmix the boundary layer this far out.

Edited April 11, 2022 by ClicheVortex2014