April 11-13, 2022 | Tornado Outbreak

[Chinook]

another look into the high reflectivity aloft of the non-tornado warned storm

 

[ClicheVortex2014]

I love FV3. Always good for some complete nonsense.

[ClicheVortex2014]

Supercells are riding the warm front to the southeast now. Hooks galore.

 

[ClicheVortex2014]

ARW and NSSL

[Central Illinois]

[Central Illinois]

 

[voltwaffle]

Mike Morgan posted this 3 hours ago

https://www.facebook.com/MikeMorganKFOR/videos/3186987298294589/

Edit: No idea why it won't embed

Edited April 12, 2022 by voltwaffle

[snowlover2]

ILN sounds like they are getting more concerned about a tornado threat here.

Quote

.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM WEDNESDAY/...
Upper level pattern amplifies further tonight into Wednesday due
to a large trough digging into the central Plains. While much
of the overnight will be dry, a shortwave trough in the southern
Plains slips northeastward within the southwesterly mid-level
flow. This will result in scattered shower and thunderstorm
development overnight across the middle Mississippi Valley and
lower Ohio Valley. Currently have PoP chances increasing from
southwest to northeast by sunrise Tuesday morning. A few
elevated thunderstorms with small hail are possible as well.

Through the mid-morning and afternoon, the shortwave progress
through the Ohio Valley, enhancing the threat for additional
development of elevated showers and thunderstorms. This is
highlighted by a northwest-southeast oriented branch of
categorical PoPs passing through from southwest to northeast.
All of this activity will occur ahead of any thunderstorms
developing with the front well west of the area. The severe
threat with the thunderstorm activity ahead of the primary line
will be low and primarily focused on the threat for small hail.
All details for Wednesday night`s severe threat is located in
the long-term portion of the discussion.

Within the warm sector of the surface low, southwest winds will
be breezy through the day on Wednesday with gusts around 30 mph
occurring area wide. Temperatures will attempt to warm up into
the 70s but if an earlier arrival of rain occurs, some locations
may observe temperatures in the 60s.

&&

.LONG TERM /WEDNESDAY NIGHT THROUGH MONDAY/...
The weather setup for the start of the long term period, namely
Wednesday evening into Wednesday night, continues to be
concerning, to say the least. A stacked/deepening low pressure
system will be positioned initially over the northern plains
before drifting E across the upper Midwest for the start of the
long term period. The corresponding deep troughing near the mid
MS Rvr Vly will be complemented by ridging downstream across the
Atlantic coast, with deep-layer S/SW flow from the Gulf into
the OH/TN Vlys.

Already by late Wednesday afternoon, there is the expectation
for widespread/deep convection initiating off a strong eastward-
moving frontal boundary across western parts of the OH Vly,
initially well to the west of the ILN FA. This will be separate
from the open warm- sector convection closer to, and in, the
local area Wednesday afternoon. That well-defined front will
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. There are still some subtle timing
differences with regards to the frontal passage, but the main
impacts locally seem likely to occur in the late Wednesday
evening into early/mid Wednesday night time period.

This is a very dynamic system that will be working its way
through central/eastern CONUS, and both the LL and deep-layer
shear reflect that. 0-1km bulk shear will approach 40+kts
locally after 00z Thursday with 0-3km bulk shear at about a
230-degree orientation at around 45-50kts. Deeper-
layer/effective shear around 50kts will also be present as the
front approaches, supporting organization of convection. What
continues to remain somewhat in question is the degree of SB-
destabilization that can occur locally as the front quickly
moves in late Wednesday evening. There are several hi-res and
synoptic-based solutions to suggest a narrow ribbon of SB-instby
will accompany the arrival of the more strongly-forced
convection. This SBCAPE will be collocated with a narrow axis of
richer LL moisture return, characterized by DPs in excess of
60F nosing N in the several hour period ahead of the convective
line arrival. This is in spite of the expectation for widespread
/open-warm sector convection ongoing through much of Wednesday
afternoon across the ILN FA. And although there is the potential
for hail with this daytime activity, it is likely to remain
somewhat elevated in nature until the evening. Once any activity
can become SB, and this may occur in a few hour window before
the frontal-forced convective line, all severe hazards may come
into play until the QLCS brings a more concentrated threat for
strong/damaging winds later in the evening into the overnight.
What remains concerning about this setup is the orientation of
the LL bulk shear vector to the front itself, which may be
offset by as much as 50 degrees or so, with substantial
directional shear in the lowest km or two. This will support
0-1km SRH in excess of 300m2/s2 and 0-3km SRH in excess of
400m2/s2, lending itself to some concern for tornadic activity,
particularly in any convective activity /immediately/ ahead of
the main QLCS, as well as attendant to the leading edge of the
QLCS as well. The latest data does continue to suggest the
slightly less favorable LL thermodynamic environment with
eastward extent, mainly owing to the less substantial moisture-
rich BL across parts of central/south- central OH/NE KY. So
there remains the likelihood that the severe threat should wane
with eastward extent, although there will still be a severe risk
in these areas as the forcing/shear alone will keep the
convection going past the middle of the night for the eastern
third or so of the ILN FA. But the slightly drier BL/lower SB-
instby in these areas should yield a more limited severe threat
with eastward extent/the further into the night we progress.

At this juncture, the primary concern for the late Wednesday
evening into Wednesday night time period continues to be the
potential for a QLCS to produce widespread strong/damaging
winds, with an accompanying tornadic risk as well. Both of these
threats are likely to be maximized locally near/west of I-75,
with a gradual decrease toward central/south-central OH/NE KY.
We will also have the potential for localized heavy rain both
with the convection on Wednesday afternoon, as well as
coincident with the linear convective structure as well. While
this does seem to be of less concern, with the lack of mature
vegetation and the recent rainfall, there will be the potential
for some isolated flooding as well. Will adjust wording in HWO
accordingly to encompass these threats.

In the post-frontal environment Thursday, gusty winds to
25-30kts re expected, especially near/N of I-70 where the combo
of a tighter pressure gradient and sufficient mixing will
promote breezier conditions. And by late in the workweek, the
large/vertically- stacked/closed low over the upper Midwest will
continue to lumber east, ejecting midlevel vorticity around its
southern base as it does so both Thursday night and again
Friday evening/night. This lends itself to some low chance PoPs,
especially for Friday evening/night where the midlevel forcing
is going to be greatest. And the messy pattern continues into
the weekend, with guidance varying wildly in how things are
going to unfold during this time period, both spatially and
temporally. One thing that does remain of higher confidence is a
return to below normal temperatures by the beginning of next
week, with several days with daytime highs potentially 15-20
degrees below seasonal norms once again. This will likely be
accompanied by periodic light pcpn associated with another
deepening/stacked system Monday/Tuesday across the eastern
CONUS.

 

 

[Neoncyclone]

Dangerous day ahead, Iowa looks to be the main target but confidence is growing in a couple supercells firing in OK as well, and with each run they're getting better defined, we'll see how it all plays out. 

[ElectricStorm]

2 hours ago, Neoncyclone said:

Dangerous day ahead, Iowa looks to be the main target but confidence is growing in a couple supercells firing in OK as well, and with each run they're getting better defined, we'll see how it all plays out. 

Of course now the models start showing some action here as soon as we get downgraded to slight risk lol

[ClicheVortex2014]

Nice squall for Indiana and western Ohio. Got a pre-frontal cluster of likely supercells in N MS/W TN.

[ClicheVortex2014]

Stunningly beautiful system but ominous in the fact that a very dangerous setup is organizing right before our eyes

[ClicheVortex2014]

NSSL has just about the worst case scenario for tomorrow. ARW is kinda questionable

[snowlover2]

They added a moderate risk in NW IA for today. 

[ElectricStorm]

Not surprised at all about the moderate risk. Big time outbreak possible up there 

[ClicheVortex2014]

Sounding for Omaha on the border of the moderate risk... crazy wind profile. Sufficiently steep mid-level lapse rates in place and I think that inversion should be pretty easy to overcome with the warm front coming through and daytime heating.

Edited April 12, 2022 by ClicheVortex2014

[Iceresistance]

8 hours ago, voltwaffle said:

Mike Morgan posted this 3 hours ago

https://www.facebook.com/MikeMorganKFOR/videos/3186987298294589/

Edit: No idea why it won't embed

He will post it on Twitter after a little while. 

 

[Iceresistance]

The wind is absolutely crazy today

[FortySixAnd32]

27 minutes ago, Iceresistance said:

The wind is absolutely crazy today

What's been the highest gust?

[Iceresistance]

1 minute ago, FortySixAnd32 said:

What's been the highest gust?

Up to 35, expected to get even crazier in the afternoon

[ClicheVortex2014]

NE OK/SE KS/SW MO has been taken out of 5% tornado. A  big blob of 5% tornado remains for the Southern Plains for the overnight activity.

[NebraskaEgg]

The moderate risk is just over the border in Iowa, kinda sad I'm not in it but at the same time I've seen some pretty strong wording. Biggest danger for me seems to be the line of storms around 10 since the afternoon discrete cells will probably be farther north.

 

Meanwhile at the end of the forecast period it says "snow showers".

[Cincysnow]

 

[ClicheVortex2014]

Keep in mind the UH tracks are from all CAMs while the STP is the mean of all CAMs. But I guess one could say there's a pretty good signal for pre-frontal convection.

Edited April 12, 2022 by ClicheVortex2014

[StormfanaticInd]

Wonder if they will issue a moderate risk for tomorrow 🤔