March 30-April 1, 2023 | Severe Weather | Destructive Tornado Outbreak with a double High Risk

[StormfanaticInd]

 

 

 

 

Edited March 29, 2023 by StormfanaticInd

[Iceresistance]

6 minutes ago, StormfanaticInd said:

 

 

The images are not in sync with each other.

[StormfanaticInd]

22 minutes ago, Iceresistance said:

The images are not in sync with each other.

Fixed. 

[StormfanaticInd]

 

[Hoosier]

Although a transition to more of a linear mode would increase the damaging wind threat, the QLCS tornado risk looks fairly substantial to me.  Forecast soundings just out ahead of the line in IL at 00z Sat are quite impressive, with 0-3 km shear of 50-70 kts.  

[ClicheVortex2014]

9 hours ago, Iceresistance said:

One of the LARGEST Enhanced Risks I have ever seen, there is definitely room for a Moderate.

Most of the time that gets shrunk down once details get ironed out, especially if clouds become a factor.

[Iceresistance]

16 minutes ago, ClicheVortex2014 said:

Most of the time that gets shrunk down once details get ironed out, especially if clouds become a factor.

It usually does, but it's huge!

 

And soundings indicate that CAPE may not matter in this setup.

[StormfanaticInd]

The parameters in Iowa and Illinois are scary

[Iceresistance]

7 minutes ago, StormfanaticInd said:

The parameters in Iowa and Illinois are scary

And in Oklahoma too, if the storms develop.

[ElectricStorm]

18z HRRR has quite a bit of cloud cover over pretty much the entire enhanced risk, with some decent morning convection over the northern parts. This run does show some signs of some slight clearing in small areas, but the majority of the area remains cloudy. 

It's not exactly the same, but this kind of reminds me of 3/28/20 where the morning convection/clouds really limited that event. Of course this is only the 18z run which doesn't go through the peak event, but it's definitely something to keep an eye on as we get closer.

Note: That probably wouldn't limit any potential QLCS much, I'm just talking from a discrete pre-squall supercell/tornado perspective. 

Edited March 29, 2023 by ElectricStorm

[Ingyball]

29 minutes ago, Iceresistance said:

And in Oklahoma too, if the storms develop.

I'm more worried about the fire potential in Oklahoma, especially along and west of I-44. Could be a bad day for the Southern Plains. 

[Hoosier]

57 minutes ago, ElectricStorm said:

18z HRRR has quite a bit of cloud cover over pretty much the entire enhanced risk, with some decent morning convection over the northern parts. This run does show some signs of some slight clearing in small areas, but the majority of the area remains cloudy. 

It's not exactly the same, but this kind of reminds me of 3/28/20 where the morning convection/clouds really limited that event. Of course this is only the 18z run which doesn't go through the peak event, but it's definitely something to keep an eye on as we get closer.

Note: That probably wouldn't limit any potential QLCS much, I'm just talking from a discrete pre-squall supercell/tornado perspective. 

The HRRR does have some clearing moving into IA/MO toward the end of the run, which would probably continue eastward beyond that.  

I'm not sure that some cloudiness is necessarily a bad thing for this setup.  Moisture quality/depth is ok, though not great, and a long period of unabated sun would have me concerned about some of that drier air aloft mixing down and lowering dewpoints.  The steep lapse rates aloft are a key factor in aiding instability in this setup, so it's not as important to completely maximize surface heating.  

[Iceresistance]

1 hour ago, Ingyball said:

I'm more worried about the fire potential in Oklahoma, especially along and west of I-44. Could be a bad day for the Southern Plains. 

Yeah, and the wind with the dust.

[ClicheVortex2014]

Be curious if something like this verifies. Gravity waves Friday? HRRR seems to think it'll help mix down some 50+ mph winds.

Edited March 30, 2023 by ClicheVortex2014

[ElectricStorm]

Well the 0z HRRR is certainly something. Has a big line of semi-discrete cells for the southern half of the enhanced risk, and prefrontal supercells in IA. Has more clearing than 18z did as well if this run verified exactly that would probably be a major tornado outbreak. 

Luckily the 48 hour HRRR isn't super reliable but once again this looks like another fine line between mostly linear or significant outbreak. It'll be interesting to read the Day 2 outlook.

[Neoncyclone]

Just now, ElectricStorm said:

Well the 0z HRRR is certainly something. Has a big line of semi-discrete cells for the southern half of the enhanced risk, and prefrontal supercells in IA. Has more clearing than 18z did as well if this run verified exactly that would probably be a major tornado outbreak. 

Luckily the 48 hour HRRR isn't super reliable but once again this looks like another fine line between mostly linear or significant outbreak. It'll be interesting to read the Day 2 outlook.

Definitely concerning, If it verified it would surely be a significant outbreak. However in terms of outliers the HRRR is an outlier against many model with quality of moisture, 65 degree dewpoints overspreading Northern Illinois with widespread 62-64 degree dewpoints across Illinois. Most models don't have near that much north-ward extent.

[DJKuo]

19 minutes ago, Neoncyclone said:

Definitely concerning, If it verified it would surely be a significant outbreak. However in terms of outliers the HRRR is an outlier against many model with quality of moisture, 65 degree dewpoints overspreading Northern Illinois with widespread 62-64 degree dewpoints across Illinois. Most models don't have near that much north-ward extent.

Yeah something weird with the 00z HRRR showing a temp spike in the 80s behind the line of storms in MO/IL 

 

Meanwhile NAM 3km barely bringing it up to 70F same time and area

Edited March 30, 2023 by DJKuo

[StormfanaticInd]

This is looking more and more like a tornado outbreak. 

[snowlover2]

2 moderate risk areas on new day 2. One for tornadoes and one for wind.

Quote

 Day 2 Convective Outlook  
   NWS Storm Prediction Center Norman OK
   1257 AM CDT Thu Mar 30 2023

   Valid 311200Z - 011200Z

   ...THERE IS A MODERATE RISK OF SEVERE THUNDERSTORMS ACROSS EASTERN
   IOWA INTO NORTHWEST ILLINOIS...AND ACROSS NORTHEAST ARKANSAS...THE
   MISSOURI BOOTHEEL...EXTREME WESTERN KENTUCKY...WESTERN
   TENNESSEE...AND FAR NORTHWEST MISSISSIPPI...

   ...SUMMARY...
   Intense and widespread severe thunderstorms are expected Friday
   afternoon into the overnight hours across portions of the Middle
   Mississippi Valley and Mid-South vicinity, eastward to the Lower
   Ohio and Tennessee Valleys. Intense, damaging gusts and several
   tornadoes (some strong and long-track) are expected.

   ...A bi-modal regional outbreak of severe storms is expected on
   Friday from the Mid-Mississippi Valley into the Mid-South...

   ...Synopsis...

   An amplified large-scale upper trough will be oriented from the
   northern plains to the southern Rockies early Friday. The trough
   will continue to deepen as it shifts east toward the MS Valley by
   00z, and oriented from the upper Great Lakes to the TN Valley
   vicinity by Saturday morning. With time, a closed low is expected to
   develop over eastern SD/NE/IA and a 100+ kt 500 mb jet will
   overspread the Mid-MS/OH Valley region. Intense southwesterly
   low-level flow also will overspread the Mid-South through much of
   the Midwest, with an 850 mb jet around 65-80 kt forecast by late
   afternoon into the overnight hours.

   At the surface, a deepening low centered over eastern NE/western IA
   Friday morning will shift east across IA through the afternoon
   before lifting toward southern Ontario overnight. A trailing cold
   front will extend from the low into eastern KS/central
   OK/west-central TX at 12z, and shift east across much of the Midwest
   and Mid-South. Ahead of the eastward-advancing front, strong
   southerly flow will transport 60s F dewpoints northward. Near-60 F
   dewpoints are expected as far north as eastern IA into northern IL
   during the afternoon. The warm sector will become more
   narrow/pinched off with north and east extent toward the Ohio Valley
   during the evening/overnight hours. However, near 60 F dewpoints are
   still expected in a narrow corridor ahead of the surging cold front
   into far southern IN and central KY. Richer boundary-layer moisture
   will reside from the Mid-South into the Lower-MS/TN Valleys where
   low to mid 60s F dewpoints are forecast.

   ...Mid-Mississippi Valley Vicinity...

   The strongest forcing/DCVA will be located over northern portions of
   the Mid-MS Valley close to the surface low/triple point. The
   expectation is that rapid destabilization through the morning
   (1000-2000 J/kg SBCAPE) and arrival of stronger forcing by early
   afternoon will result in initial supercell development near the
   surface low. All severe hazards will be possible with these fast
   moving storms, including a couple of strong tornadoes, intense
   damaging gusts and large hail. Cellular activity should spread
   across eastern IA/northern MO and into northwest IL before tendency
   toward upscale growth into linear convection ensues with eastward
   extent as convection develops south and east ahead of the front from
   east-central MO into northern/central IL. Damaging gusts will become
   more prominent with linear convection, though QLCS tornadoes will
   also be possible. 

   Additional storms will likely form near/just north of the warm front
   and move into parts of far southeast MN and southern WI. This
   activity should remain elevated, posing a risk for large hail and
   strong gusts, though any cell rooting on the warm front will pose a
   tornado risk as well, though the better warm sector is expected to
   remain south of MN/WI. 

   ...Mid-South Vicinity...

   A concerning scenario appears to be developing across portions of
   the MO Bootheel, northeast AR, western TN/KY and far northwest MS
   vicinity during the afternoon/evening. At least mid-60s F dewpoints
   are expected beneath modest midlevel lapse rates. This will support
   1500-2000 J/kg MLCAPE amid intense vertical shear. Forecast
   soundings indicate 0-1 km SRH increasing to around 400 m2/s2 by
   early afternoon. Thunderstorms are expected to develop by early
   afternoon ahead of the cold front within a pre-frontal
   trough/low-level confluence zone. Storm motion near 50 kt with
   supercell wind profiles will support cells capable of significant
   and long-track tornadoes. With time, upscale growth into a QLCS is
   expected, and intense wind gusts will be possible in addition to
   mesovortex tornadoes.

   ...OH/TN Valley vicinity...

   Low-level moisture/instability will begin to wane with north and
   east extent into the nighttime hours. However forecast guidance has
   consistently shown a few hundred J/kg MLCAPE with little/no
   inhibition. Forecast guidance generally tends to under-forecast
   north/east extent of severe potential in strongly forced, intense
   shear system. As such, the ongoing outlook maintains a broad
   gradient from Enhanced to Slight risk across this region. Damaging
   gusts and a few QLCS tornadoes will be possible into the nighttime
   hours.

 

Edited March 30, 2023 by snowlover2

[ElectricStorm]

It'll be interesting to see if anything can form in the marginal risk here, anything that can break the cap here could be a tornado threat but I don't really know if anything will be able to. 2% tor area is up so you never know... A nice non-severe storm would be nice 

[Neoncyclone]

The HRRR still hasn't backed down from the idea of 60+ dewpoints well into Northern Illinois/Iowa. 

[Grace]

57 minutes ago, Neoncyclone said:

The HRRR still hasn't backed down from the idea of 60+ dewpoints well into Northern Illinois/Iowa. 

 

Definitely looks concerning. There's just so much model difference on details that makes such a difference in a big outbreak versus just spring thunderstorms with some severe. 

[Hoosier]

Pretty impressive dry air surge behind the moisture plume on the HRRR.  Like a pseudo dryline.  This shows up on other models to some extent but the HRRR is the most dramatic.  

[snowlover2]

ILN saying there could be isolated tornadoes.

Quote

.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM FRIDAY/...
Clouds will be on the increase tonight well ahead of the next
storm system organizing over the central Plains. An initial s/w
in the mid level flow will team up with an increasing low level
jet which will push into our area by Friday morning. Moisture
and lift with these features will spread showers into our
western zones late. Winds will also increase from the south as
the surface pressure gradient tightens. Temperatures will drop
off some this evening, then they will rise some overnight as
clouds thicken and winds pick up. Lows will range from the lower
40s north and east to the upper 40s west.

On Friday, a mid level trough will be moving east across the
central Plains while its associated surface low deepens as it
heads toward western Wisconsin. Showers and some elevated
thunderstorms will occur across our area as another mid level
s/wv and focused low level jet energy keep a period of lift over
our area. It will be breezy to locally windy as southerly flow
continues. Wind gusts will generally range between 25 and 35 mph
with some isolated gusts near 40 mph possible. Despite the
clouds and pcpn, southerly flow and WAA should boost
temperatures into the lower 60s region wide.

&&

.LONG TERM /FRIDAY NIGHT THROUGH WEDNESDAY/...
Two potent weather systems will impact the long term. The first
low tracking to the Great Lakes on Friday night will bring
widespread showers and a few thunderstorms. As a cold front
moves through, instability will be marginal, though
thunderstorms may be severe in the highly sheared environment,
and isolated tornadoes will be possible. Rainfall may add up to
an inch or more in some locations. Strong winds will increase
Saturday behind the cold front as showers diminish, and gusts
over 40 knots will be likely.

 

[Hoosier]

Forecast soundings are nasty tomorrow.  Focusing more on the northern target for obvious reason of it being closer to home, but a volatile environment is present around IA/IL in the afternoon.  The "barb of death" is also present as some old timers would say, with 500 mb winds in excess of 100 kts in the area.  That phrase is just what it sounds like, in that it tends to result in bad outcomes with deadly tornadoes.  Do see a tendency for some minor surface CINH with eastward extent in IL and IN, but it may not be enough to preclude a tornado threat into those areas and there could be some local augmentation of the profiles anyway in that kind of shear environment.  Stay safe and be careful chasing.