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2022 Short/Medium Range Severe Thread


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1 minute ago, Hoosier said:

There's a hatched 15% wind area on the day 2 outlook, owing to the uncertainty/varying scenarios but with higher end potential.

 

 Forecast Discussion
   SPC AC 120558

   Day 2 Convective Outlook  
   NWS Storm Prediction Center Norman OK
   1258 AM CDT Sun Jun 12 2022

   Valid 131200Z - 141200Z

   ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF
   THE NORTHERN PLAINS...AND THE MIDWEST/GREAT LAKES INTO THE OHIO
   VALLEY...

   ...SUMMARY...
   Scattered severe thunderstorms should develop Monday across parts of
   the northern Plains, and from portions of the Midwest into the Great
   Lakes and Ohio Valley. Large hail, damaging winds, and a few
   tornadoes all appear possible. Some of the winds could be
   significantly severe (75+ mph) across parts of the Midwest/Ohio
   Valley Monday afternoon.

   ...Synopsis...
   A large-scale upper trough initially over the western CONUS will
   move slowly eastward across the Intermountain West on Monday,
   eventually reaching the northern/central Rockies and adjacent High
   Plains by late Monday night. An upper-level ridge should persist
   over much of the MS Valley into the Southeast, with another upper
   low forecast to remain over Quebec. Enhanced west-northwesterly
   mid-level flow should be present over parts of the Midwest into the
   Great Lakes, OH Valley, and Mid-Atlantic on the northeast side of
   the upper ridge.

   At the surface, a lee cyclone should consolidate over the northern
   and central High Plains by Monday evening, with another low over
   southern Saskatchewan. Rich low-level moisture should return
   northward across much of the northern Plains along/east of a front
   extending between the two surface lows. A warm front is also
   expected to lift northward across parts of the Midwest into the
   Great Lakes and OH Valley through the day, with a very moist
   low-level airmass present along/south of the warm front.

   ...Northern Plains...
   Modest mid-level height falls and ascent preceding an upper trough
   should overspread parts of the northern Plains by Monday evening.
   Diurnal heating of a moist low-level airmass to the east of a front
   should encourage the development of moderate to strong instability
   by late Monday afternoon across parts of western SD and vicinity.
   Strong deep-layer shear of 50+ kt will easily support supercells
   with any convection that can develop and persist. Most guidance
   suggests that thunderstorms will initially develop by late Monday
   afternoon across far northeastern WY/southeastern MT, and quickly
   strengthen as they spread northeastward across western/central SD
   and ND Monday evening/night.

   The rather favorable thermodynamic and kinematic environment will
   support a threat for both large hail and severe winds with
   supercells as the dominant mode initially. Some of the hail could be
   very large (2+ inches) across parts of western SD and vicinity
   Monday afternoon/evening, as steep mid-level lapse rates and
   2000-3000+ J/kg of MLCAPE will likely be present. With time, some
   upscale growth into a cluster may occur across ND Monday night as a
   cold front moves eastward. Given the large amount of buoyancy
   forecast, damaging winds and hail may continue to be a threat even
   if convection becomes slightly elevated. A few tornadoes may also
   occur with any supercell, mainly late Monday afternoon and early
   evening, across parts of western SD into ND as low-level shear
   increases.

   ...Upper Midwest into the Great Lakes and Ohio Valley...
   Thunderstorms may be ongoing at the start of the period Monday
   morning across parts of the Midwest (IA/MN and vicinity). This
   activity could pose an isolated severe hail/wind threat as it moves
   eastward Monday morning. There may be an MCV associated with this
   morning convection, and some guidance also shows a corresponding
   mid-level vorticity maximum and enhancement to the mid-level winds.
   Although details in convective evolution remain unclear Monday
   afternoon, there is increasing concern that redevelopment of intense
   thunderstorms could occur with the MCV across parts of southern
   WI/northern IL into southern Lower MI, IN, and OH. Strong to extreme
   instability (MLCAPE 3000-5500+ J/kg) will likely develop along/south
   of a warm front across these areas. Low to mid 70s surface
   dewpoints, strong diurnal heating, and steep mid-level lapse rates
   will all contribute to this large reservoir of buoyancy. 35-45+ kt
   of deep-layer shear should also be present with the enhanced
   mid-level west-northwesterly flow on the northeastern periphery of
   the upper ridge.

   This volatile environment will support significant severe potential
   with any thunderstorms that can form along/south of the warm front.
   At this point, there is still a substantial amount of uncertainty
   with where/if thunderstorms redevelop by Monday afternoon. Both
   global and convection-allowing model guidance show large variability
   in possible solutions, which range from little to no surface-based
   convective redevelopment, to an intense, bowing MCS sweeping
   southeastward in a narrow corridor across parts of the Midwest into
   the OH Valley through Monday evening. Given these uncertainties,
   have opted to include greater (15%) severe wind probabilities and
   add a significant severe wind area where confidence in an MCS
   occurring is somewhat better. Isolated large hail may occur with any
   embedded supercell. A few tornadoes also appear possible, as
   low-level shear will be maximized along and just south of the warm
   front.

   If confidence in the MCS scenario occurring increases, then even
   greater severe probabilities would likely be needed owing to the
   very favorable thermodynamic environment. The eastern/southern
   extent of the severe threat is also uncertain, so have expanded the
   Marginal Risk across the OH Valley into the central Appalachians to
   account for a broad range of possible tracks to the MCS before it
   eventually weakens Monday night.

   ..Gleason.. 06/12/2022

Beat me to it. That's some pretty strong wording.

spcd2four_panel.conus.png

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Will be curious to see the new day 2 outlook.  Could make a case for trimming the southern end but not sure they will.  You want to have some buffer and we've all seen plenty of times where things end up south of where you'd think based on models.  In this case we are dealing with an infernal airmass aloft coming in and I'm not sure how far south any convection can end up, but we'll see.

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2 hours ago, SolidIcewx said:

I certainly hope one does occur I’ve been wishing for a strong MCS or MCV to hit the DTW area. The potential instability of up to 5000 j/kg is pretty gnarly for this area

Didn't that happen on 6/1?

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33 minutes ago, Hoosier said:

Will be curious to see the new day 2 outlook.  Could make a case for trimming the southern end but not sure they will.  You want to have some buffer and we've all seen plenty of times where things end up south of where you'd think based on models.  In this case we are dealing with an infernal airmass aloft coming in and I'm not sure how far south any convection can end up, but we'll see.

Yeah not sure why we are in it, gonna be hot and capped here.  Not a very good day2 for DVN area to be sure.  Sunny and 95+ here, with distant anvils on northeast horizon.

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17 minutes ago, Hoosier said:

Will be curious to see the new day 2 outlook.  Could make a case for trimming the southern end but not sure they will.  You want to have some buffer and we've all seen plenty of times where things end up south of where you'd think based on models.  In this case we are dealing with an infernal airmass aloft coming in and I'm not sure how far south any convection can end up, but we'll see.

Maybe their thinking is the farther north solutions have less wind threat due to the best instability being slightly elevated in those cases.  The warm front is moving north and will have some clouds associated with it.  In any case, I think 80 degree dewpoints will eventually overcome any cap once a strong cold pool is established.  Even if Illinois is missed, it could still do the hard right turn moving into Michigan then back build across Indiana. 

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36 minutes ago, Powerball said:

Didn't that happen on 6/1?

That one blew up once it passed the Detroit  river was a good show where I was in Ypsilanti at work. But I’m referring to your textbook MCS like the ones that formed in the plains past month or so. (On a side note it means I get overtime with storms like that)

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5 minutes ago, cyclone77 said:

Yeah not sure why we are in it, gonna be hot and capped here.  Not a very good day2 for DVN area to be sure.  Sunny and 95+ here, with distant anvils on northeast horizon.

Yea.  If I were them I'd adjust the orientation.  It will probably be more NW-SE.  Northern Indiana will get hit.  Northern Illinois, not so likely.

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24 minutes ago, SolidIcewx said:

That one blew up once it passed the Detroit  river was a good show where I was in Ypsilanti at work. But I’m referring to your textbook MCS like the ones that formed in the plains past month or so. (On a side note it means I get overtime with storms like that)

From all the pictures and storm reports I saw, 6/1 was definitely a impressive storm for the city proper.

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4 hours ago, SolidIcewx said:

image.gif.fae5a1f7b84f8f851b4d6a1cd8ab2739.gifshows Michigan getting smoked and also into northern Ohio would be interesting to see just one model of course

I don’t know how to feel about a derecho followed by 100+ heat indeces IMBY.  My folks are in the process of moving and having power out into Tuesday will be a nightmare.

Hope it misses south honestly.

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HRRR with a whiff north for MBY...which is OK since I'll be trying to get my semi-crippled car to a place where it can be worked on. It also implies that the very volatile surface-based/ :twister:environment along/south of the warm front will remain untapped.

The bowing MCS for tomorrow PM is also virtually nonexistent on the 18Z 3KM NAM, which is shocking because I've always observed that model to blow up gigantic convective complexes at the slightest provocation.

Edit: It has one large complex in east-central IL into IN, and another in Iowa at 14Z, so those probably work over the environment for the would-be later activity according to the model's scenario.

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42 minutes ago, CheeselandSkies said:
HRRR with a whiff north for MBY...which is OK since I'll be trying to get my semi-crippled car to a place where it can be worked on. It also implies that the very volatile surface-based/ :twister:environment along/south of the warm front will remain untapped.
The bowing MCS for tomorrow PM is also virtually nonexistent on the 18Z 3KM NAM, which is shocking because I've always observed that model to blow up gigantic convective complexes at the slightest provocation.
Edit: It has one large complex in east-central IL into IN, and another in Iowa at 14Z, so those probably work over the environment for the would-be later activity according to the model's scenario.


CAMS are struggling significantly right now, especially the 3KM NAM.

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It's hard to overstate how thermodynamic the instability will be Monday and Monday night...you've got this pristine EML advecting in:

LBF.thumb.png.980cb80017031e51f0cf862418bc10f1.png

OAX.thumb.png.b24cb34571cbcf716e3bc32eb9d45861.png

TOP.thumb.png.db1968481e92a1220bd315d38324dc9c.png

This impressively rich low-level moisture will be advecting into the Ohio Valley, southern Great Lakes, and Upper Mississippi Valley beneath the advecting EML:

ILX.thumb.png.f553719c6dc750de81f6ee839774fa91.png

BNA.thumb.png.617c59c8d955d9dd5c841e8f97829053.png

Despite the outstanding thermodynamics, the synoptic forcing is fairly modest (some right-entrance support over the Great Lakes) and at the base of the EML will be very warm 700-850mb temperatures acting as a cap:

CODNEXLAB-FORECAST-2022061221-RAP-US-700-temp-0-39-100.gif.20a074faba1056b05b5f0a1099acaaaf.gif

The cap will be breakable in a narrow zone along and just north of the warm front...but with weak synoptic forcing, more robust convective development and subsequent upscale growth will likely be heavily tied to MCVs leftover from tonight's convection moving out of the Plains. A strong MCV will likely spark a robust subsequent MCS from the Upper Mississippi Valley into parts of the southern Great Lakes, mid or upper Ohio Valley, central Appalachians and perhaps eventually the Mid Atlantic. Given the thermodynamics and shear in place, the potential would exist for such an MCS to produce enough wind damage to be considered a derecho. 

However, CAMs so far struggling to agree on a solution. This is likely due to how sensitive the set-up is to tonight's upstream convection and MCVs it leaves into tomorrow (along with perhaps some modest strengthening of the upper level jet streak glancing the region), along with multiple forcing mechanisms and a rich environment to work with. There may be multiple MCVs, and some modest lift feeding into the right-entrance quadrant glancing the region may also aid some in allowing for convection that initiates to grow upscale:

CODNEXLAB-FORECAST-2022061221-RAP-US-500-avort-3-36-100.gif.31246109d93a91b84157146188c86825.gif

Can note the multiple subtle vorts/perturbations drifting out of the Plains into the Upper Midwest and Great Lakes as a result from tonight's convection in the Plains...these will likely be very tied to where new activity initiates on Monday.

CODNEXLAB-FORECAST-2022061221-RAP-US-250-spd-3-39-100.gif.c865477d371741108623e9e3f3b4866b.gif

Can also note the right-entrance quadrant of a jet streak glancing the region, along with some hints that whatever upper level outflow occurs from convection over the Upper Midwest or Great Lakes may positively feedback with that for a time. 

If multiple rounds initiate at about the same time Monday afternoon or evening, there could be enough competition to lower the potential for any one cluster to turn into a particularly long-lasting and potent wind producer. 

Overall, my gut feeling is that at least one cluster will be dominant enough for a time to produce a pretty good swath of wind damage, but this could happen anywhere from the Upper Mississippi Valley to the lower Great Lakes, mid and upper Ohio Valley, central Appalachians or even Mid Atlantic between Monday afternoon and Tuesday morning. Potential exists for a higher-end event to be sure, but several ways it's at least somewhat limited. The MCV running east/southeast quickly may cause initiation earlier than optimal towards the Ohio Valley, slowing moisture/instability return farther north and also not taking full advantage of the environment coming together. Multiple areas of initiation at the same time could limit longevity of anything really potent, as there'd be too much competition eventually as stuff grows upscale. The greatest potential for a derecho to playout would be if initiation occurred mid-late afternoon in the Upper Mississippi Valley with one relatively dominant cluster and little out ahead of it, with the activity spreading through the southern Great Lakes into the evening and into the mid-upper Ohio Valley late evening or towards the overnight.

Given rich theta-e air feeding in from the southwest through Monday night, if we do see one or more MCSs producing robust cold pools, back-building and flash flooding may locally become a problem as the moist and unstable air would get lofted over the shallow cold pools by the low-level jet overnight, possibly causing back-building.

Any initial cellular convection would have a large to perhaps very large hail risk given the robust EML and huge instability...some tornado risk too, both with any initial supercells and with any more robust bowing segments that may play out as stuff grows upscale. 

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Parameters on 3 km NAM are pretty wild in northern IL/IN tomorrow.

This is almost like some severe wx nerd sitting in the basement and drawing soundings.  Not even the most extreme forecast sounding that I found.

nam4km-2022061300-024-41-53-87-41.png

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8 minutes ago, Hoosier said:

Parameters on 3 km NAM are pretty wild in northern IL/IN tomorrow.

This is almost like some severe wx nerd sitting in the basement and drawing soundings.  Not even the most extreme forecast sounding that I found.

nam4km-2022061300-024-41-53-87-41.png

I put those coordinates in a map finder and get the corner of Dallas and Elm Streets. Your basement?

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I’ve been through plenty of monster MCS/derecho’s, and now that I’m an adult, the prospect of going through a heat wave without power for several days isn’t quite worth the fun of the storm. Don’t get old, kids.

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