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March 31st Severe Threat


pen_artist
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This definitely looks like a very significant event for Friday that would cover a good portion of the western part of the subforum. The instability has only trended upward run to run for the areas of MO/IA/IL, with an incredibly dynamic wind field. I would suspect we see a day 2 MDT come out tonight for a large area all the way down to Memphis.

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11 minutes ago, Stebo said:

This definitely looks like a very significant event for Friday that would cover a good portion of the western part of the subforum. The instability has only trended upward run to run for the areas of MO/IA/IL, with an incredibly dynamic wind field. I would suspect we see a day 2 MDT come out tonight for a large area all the way down to Memphis.


Thanks, was wondering if that was coming. Looks like a pretty high impact day. Always appreciate met analysis on here. 

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6 minutes ago, Chambana said:


Thanks, was wondering if that was coming. Looks like a pretty high impact day. Always appreciate met analysis on here. 

Not the place in this thread but I am very much watching Tuesday/Wednesday for an even bigger potential in the region.

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39 minutes ago, Stebo said:

Not the place in this thread but I am very much watching Tuesday/Wednesday for an even bigger potential in the region.

Chiming in from outside the region. Friday looks like a sure bet for a large swath of severe weather - straight line wind damage specifically. Next Tuesday as you suggest might be even worse a the front is pegged to be more robust. Until the jet ramps down every front is going to spin these storms in roughly same area. Every five days for the first two weeks of April at this point seems like a good bet for a large swath of significant severe weather (if not outright tornadic) in the MS to OH valleys.

The setup is ideal for spinning tops.  

/goes back to lurking for the Friday event to unfold

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Just now, andyhb said:

Predictably, the 00z HRRR is insane.

Lots more instability up into the Midwest than the NAMs, although the hodographs are surprisingly fairly straight, at least early on, in the face of such a powerhouse low. Any thoughts as to why that might be?

...oh, and of course, a simulated supercell into the Chicago area.

 

:twister:

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Just now, madwx said:

We wedging boys

:yikes:

Actually, the hodographs/wind barbs on the forecast soundings (with less clockwise curvature/veering with height than I'd like) remind me of two setups last year...one of which produced a violent, long-track discrete supercell tornado, and the other did not (but still produced strong embedded/QLCS tornadoes).

3/5 and 5/30.

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Bimodal D2 MDT, one closer to the surface low with a 10 hatched tornado risk (wind driven), the other in the Mid South with a 15 hatched tornado risk.

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.

   ..Leitman.. 03/30/2023
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10 hours ago, nwohweather said:

It’s the Midwest so squares with the occasional river road :lol:

 

 

Its not quite as bad as Lake Michigan, but the Mississippi doesn’t have bridges everywhere.  I also feel like you need the interstates to keep ahead of cells moving 50mph+.  I don’t know if its the same everywhere but its definitely pothole season around here.

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Is this model generally historically accurate? Legit asking I’m not familiar with it. 
The WRF lines up pretty well with the new D2 dual Mod Risks. 15% hatched in the area of the absurd UH swath the WRF was showing.

Sent from my Pixel 6 using Tapatalk


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Starting to look like the race westward from the suburbs might just be on tomorrow. Figure I'd hug 39 for easy relocation unless that ends up being too far east. Gonna be a nail biter though, if I'm gonna do it I'd really like to be on a storm from the minute it goes severe but I dunno if I'll be able to get  there in time. 

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15 minutes ago, hawkeye_wx said:

Hmmm.....  The HRRR has mid 70s and storms forming east of Cedar Rapids.  The 3k NAM has low 60s and storms forming near Des Moines.  :huh:

Differences between these are too much to ignore tbh. Have to wonder if the HRRR is too juiced, though several other non-NAM CAMs and even the NBM seem to be leaning warmer with larger areas of 60+ dews.

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52 minutes ago, SchaumburgStormer said:

Has discrete sups heading towards the metro. :yikes:image.thumb.png.74baea64a9705fb76932ae153bca6489.png

Have to be a little concerned that the amount of forcing aloft will create too many storms and hurt tornado chances. A lot rides on that EML plume putting in the right amount of capping for tomorrow. I will say once that QLCS comes together it should be going toll road speeds across the region. Also could see some rather large hail for the region as well. Definitely looks like a wild Midwest day to say the least 

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