Apr. 6-8 Severe Risks

[Tim from Springfield (IL)]

Not sure if the next three days warrant a separate severe thread but this was prompted by huge changes this afternoon to tomorrow's Day 2 outlook.

The narrow marginal risk for today from the LOT CWA to NW OH remains intact at this time.  Also a marginal in C/W Minnesota too:

https://www.spc.noaa.gov/products/outlook/day1otlk.html

 

...Great Lakes including portions of IL/IN/OH and Lower MI...
   Scattered thunderstorms are still expected to develop this evening,
   initially across northern Illinois and the southern Lake Michigan
   vicinity, and subsequently expand and develop eastward across other
   parts of the region through the overnight. This activity will be
   focused along/just north of a northward-advancing warm front as
   low-level warm/moist advection increases.

   In an environment characterized by steep mid-level lapse rates and 
   MUCAPE of 500-1000 J/kg in the presence of 30-45 kt effective-shear,
   the more robust elevated updrafts may produce occasionally severe
   hail. A seemingly less certain risk of locally damaging winds cannot
   be ruled out, particularly if storm mergers/organization occurs in
   immediate proximity of the surface warm front.

   ...Eastern Dakotas/western Minnesota...
   Isolated thunderstorms are expected to develop by evening across
   parts of the region, influenced by weak height falls and increasing
   warm advection related to an amplifying trough over the Canadian
   prairies. While the overall environment will not be particularly
   moist, given steep mid-level lapse rates and ample shear through the
   cloud-bearing layer, it is conceivable that a couple of the stronger
   storms could produce hail to near severe levels tonight.

 

[Tim from Springfield (IL)]

Huge change this afternoon to tomorrow's Day 2 slight, now it covers basically STL eastward to the Mid-Atlantic, including roughly I-72 southward in Illinois:

https://www.spc.noaa.gov/products/outlook/day2otlk.html

 

...The Ohio Valley Region and vicinity...
   Morning convection -- and possibly some accompanying severe
   potential -- should be ongoing over the Ohio vicinity, and will
   shift southeastward across the central Appalachians through the
   morning in tandem with a mid-level vort max.  Subsidence aloft in
   the wake of this feature -- within background ridging -- should
   maintain a capping inversion, which should hinder new convective
   development through the day ahead of a weak/advancing front/wind
   shift, associated with the next in a series of mid-level vorticity
   maxima progressing through west-northwesterly flow aloft.

   At this time, degree and timing of new storm development over the
   Ohio Valley remains quite uncertain, but current thinking is that
   scattered to isolated storms should develop along the weak boundary,
   from lower Michigan southwestward to Missouri, with the first storms
   possibly initiating by around sunset.  Convection would then spread
   east-southeastward with time across the Ohio Valley states,
   gradually increasing in coverage with time.

   Given steep lapse rates aloft, instability will support vigorous
   updrafts -- aided by the moderately strong west-northwesterlies
   through a deep layer.  Along with potential for large hail, damaging
   winds will also be possible -- particularly if storms can grow
   upscale locally into line segments/clusters.  The storms should
   continue through the overnight hours in an east-northeast to
   west-southwest band, crossing the central Appalachians and possibly
   moving into the Tennessee Valley through the end of the period.

[Tim from Springfield (IL)]

Far southern portions of the sub, including PAH, Evansville and Louisville, also in play for severe on Wednesday:

https://www.spc.noaa.gov/products/outlook/day3otlk.html

 ...Mid MS Valley into parts of the OH/TN Valleys...
   Models are showing a plume of steep 700-500mb lapse rates extending
   from the central Great Plains eastward into the lower OH Valley
   ahead of the amplifying upper trough.  This model guidance indicates
   a residual moisture reservoir (featuring 60s F dewpoints), located
   over the lower MS Valley and TN Valley, will contribute to moderate
   destabilization.  Frontal forcing will seemingly focus storm
   development during the late afternoon/early evening over the mid MS
   Valley region.  Strong mid- to high-level westerly flow will favor
   organized storms.  As convective coverage increases during the
   evening, a squall line with an accompanying risk for damaging gusts
   will move east-southeast with the threat probably extending through
   the evening and into the overnight hours.

[Chicago Storm]

Can’t figure out at all what the SPC is doing.

Not only the very questionable SWODY2, but not the new SWODY1 completely removes marginal for anywhere...when it’s pretty clear there will be a hail risk that warrants a marginal corridor.


.

[It's Always Sunny]

9 minutes ago, Chicago Storm said:

Can’t figure out at all what the SPC is doing.

Not only the very questionable SWODY2, but not the new SWODY1 completely removes marginal for anywhere...when it’s pretty clear there will be a hail risk that warrants a marginal corridor.


.

I see MRGL still included in 20Z update. Day 2 is interesting lots of things at play.  Morning convection will have a big influence on what gets going over the OH Valley in the evening.  Also models are in disagreement on placement of that LP which moves over MI tomorrow night. HRRR & ECMWF bring it through about 3-6 hours before the NAM & GFS do which can result in two completely different outcomes mainly concerning how fast OH/PA can destabilize again tomorrow afternoon. 

[Chicago Storm]

1 minute ago, It's Always Sunny said:

I see MRGL still included in 20Z update. Day 2 is interesting lots of things at play.  Morning convection will have a big influence on what gets going over the OH Valley in the evening.  Also models are in disagreement on placement of that LP which moves over MI tomorrow night. HRRR & ECMWF bring it through about 3-6 hours before the NAM & GFS do which can result in two completely different outcomes mainly concerning how fast OH/PA can destabilize again tomorrow afternoon. 

 

Yea, something is wrong with the placefile I'm using. Marginal is still there,a s you pointed out.

[Sydney Claridge]

Another point of note: observations of dew points in most of northern Ohio are in the mid-to-upper 20s right now (although dewpoints are about 50 down by Cincinnati).  Today's 12z and 18z HRRR runs show northern Ohio to be a possible area for (potential?) surface-based convection tomorrow afternoon, and I am having trouble believing this scenario given how dry the surface airmass currently is.  That said, SPC has said this would be an area of subsidence following the morning convection.

18z NAM3K puts 60s dewpoints in place across all of Illinois, Indiana, and most of Ohio (except the NE corner).  Both 18z NAM3K and NAM runs would be more favorable for isolated tornadoes given lesser T/Td spreads relative to HRRR runs (although HRRR does show more convective activity, it also shows more mixing and thus larger T/Td spreads).

[It's Always Sunny]

26 minutes ago, BrandonC_TX said:

Another point of note: observations of dew points in most of northern Ohio are in the mid-to-upper 20s right now (although dewpoints are about 50 down by Cincinnati).  Today's 12z and 18z HRRR runs show northern Ohio to be a possible area for (potential?) surface-based convection tomorrow afternoon, and I am having trouble believing this scenario given how dry the surface airmass currently is.  That said, SPC has said this would be an area of subsidence following the morning convection.

18z NAM3K puts 60s dewpoints in place across all of Illinois, Indiana, and most of Ohio (except the NE corner).  Both 18z NAM3K and NAM runs would be more favorable for isolated tornadoes given lesser T/Td spreads relative to HRRR runs (although HRRR does show more convective activity, it also shows more mixing and thus larger T/Td spreads).

Yeah I'm with you have a hard time seeing any sort of convection in northern OH tomorrow afternoon (despite HRRR showing development of a little convection there).  I just don't see the atmosphere destabilizing quickly enough to generate anything surface based at least until tomorrow evening.  It really depends on how the convection fares this evening and into tomorrow morning but an area of subsidence following the morning convection makes sense.

[Sydney Claridge]

Yikes, the 21z RAP is putting out high EHI values (and PDS TOR forecast soundings) near Chicago, and then over into northern IN and SW MI, with some precipitation in the area.  Probably overdone, but maybe that risk area does need to be shifted NW a little bit, considering that several models are putting northern Illinois in an area of severe storm risk?

[Hoosier]

Not sure how I feel about tomorrow.  A little concerned about getting meaningful initiation in time around here, but certainly the setup has potential.  

[Indystorm]

SPC currently thinking storms may erupt in northern IL about 05-06z

[madwx]

still think there may be a good shot for sfc based convection in Wisconsin tomorrow along the cold front.  Decent signal from about half the CAMs and the forcing and instability is there as long as the cap can be broken.  who knows, maybe i'm being overly optimistic

[frostfern]

I'm worried this might be one of those scenarios where convection can't get going despite what CAMs suggest.

[OHweather]

There’s fairly remarkable agreement on convection initiating around 0z or so somewhere over southern MI/central or southern IL/IN/OH, growing upscale and then moving SE.  How the morning convection plays out will contribute some to how far N the warm front gets into southern MI/northern OH, although with the EML advecting in I don’t think getting CAPE will be the issue...but how stable the low levels remain could be a limiting factor with northern/eastern extent. 
 

I don’t think there’s great tornado potential with a fairly weak and veered surface flow, along with good agreement on upscale growth happening fairly quickly as a shortwave approaches and encourages large-scale ascent Tuesday night...but initial cells could definitely produce hail given the EML/bulk shear, and assuming the low levels aren’t too stable there would certainly be a damaging wind risk too.  Despite the EML, I think the quick upscale growth may limit the potential for more than a “slight risk” for hail (though any initial cells with mid-level rotation could produce some very large hail briefly before upscale growth occurs)...if there’s agreement on the location of an evening MCS and the low levels aren’t too stable (model soundings weaken the inversion at the base of the EML somewhat along the front in the evening as the large scale ascent improves ahead of the shortwave) I could see how the wind threat justifies a 30% somewhere, though I sort of doubt we see it out of the gate at 6z. 
 

It’s sort of an interesting setup, definitely some uncertainty so will be curious to see what can happen.  We’ve gotten a couple of nice EML’s just over a week apart which is cool. 

[Jackstraw]

 Mesoscale Discussion 0291
   NWS Storm Prediction Center Norman OK
   1103 PM CDT Mon Apr 06 2020

   Areas affected...northern Illinois into northwest Ohio

   Concerning...Severe potential...Watch unlikely 

   Valid 070403Z - 070630Z

   Probability of Watch Issuance...5 percent

   SUMMARY...Storms will increase in coverage tonight, with mainly
   small hail expected. Isolated cells may produce hail approaching 1".

   DISCUSSION...Showers are beginning to form over northern IL in a
   zone of low-level warm advection which is aiding lift and
   destabilization. 00Z soundings from DVN and ILX show steep midlevel
   lapse rates, with unstable parcels originating above 850 mb. Within
   the cloud bearing layer, sufficient shear was noted to sustain storm
   cells.

   With a continued influx of relatively moist air from the southwest,
   and PWAT approaching 1.00", the result should be increasing coverage
   of elevated storms, moving in an east/southeastward direction. While
   hail will be the main threat, locally strong wind gusts cannot be
   ruled out from northern IN into OH, conditional on sufficient
   clustering of downdrafts.

   ..Jewell.. 04/07/2020

[snowlover2]

New day 1 adds hatched area for hail for IN/OH.

Quote

DAY 1 CONVECTIVE OUTLOOK  
NWS STORM PREDICTION CENTER NORMAN OK  
1250 AM CDT TUE APR 07 2020  
 
VALID 071200Z - 081200Z  
 
...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS LATE THIS  
AFTERNOON INTO TONIGHT ACROSS SOUTHERN PORTIONS OF THE GREAT LAKES  
REGION AND OHIO VALLEY INTO PARTS OF THE MID ATLANTIC COAST  
REGION...  
   
..SUMMARY  
 
SEVERE THUNDERSTORMS ARE POSSIBLE LATE THIS AFTERNOON THROUGH  
TONIGHT ACROSS SOUTHERN PORTIONS OF THE GREAT LAKES REGION INTO THE  
OHIO VALLEY AND MID ATLANTIC. STRONGEST STORMS WILL POSE A THREAT  
FOR VERY LARGE AND DAMAGING HAIL, AS WELL AS POTENTIALLY DAMAGING  
WIND GUSTS, AND PERHAPS AT LEAST SOME RISK FOR A TORNADO.  
   
..SYNOPSIS  
 
LITTLE CHANGE TO THE LARGE-SCALE PATTERN IS FORECAST THROUGH THIS  
PERIOD, WITH A HIGHER LATITUDE BLOCKING RIDGE REMAINING PROMINENT TO  
THE NORTH OF HUDSON BAY. AS BLOCKING ALSO LINGERS ACROSS THE  
MID-LATITUDE AND SUBTROPICAL EASTERN PACIFIC, ONLY SLOW MOVEMENT OF  
THE CLOSED MID-LEVEL LOW NEAR THE CALIFORNIA COAST IS FORECAST, WITH  
A GRADUAL DIGGING JUST WEST OF CENTRAL THROUGH SOUTHERN COASTAL  
AREAS.  
 
TO THE SOUTH OF THE HIGHER LATITUDE RIDGE, A DEEP MID-LEVEL CLOSED  
LOW APPEARS LIKELY TO REMAIN QUASI-STATIONARY NEAR THE CANADIAN  
MARITIMES, WHILE A STRONG JET STREAK DIGGING TO THE LEE OF THE  
CANADIAN ROCKIES CONTRIBUTES TO ANOTHER EVOLVING MID-LEVEL LOW  
NEAR/EAST OF THE CANADIAN PRAIRIES. SMALLER-SCALE PERTURBATIONS  
PROGRESSING AROUND THE SOUTHERN PERIPHERY OF THIS FEATURE WILL  
CONTRIBUTE TO MID-LEVEL HEIGHT FALLS AND INCREASINGLY CYCLONIC FLOW  
ACROSS THE NORTHERN PLAINS INTO THE UPPER MISSISSIPPI VALLEY BY LATE  
TONIGHT.  
 
ONE PRECEDING SHORT WAVE IMPULSE IS FORECAST TO ACCELERATE ACROSS  
THE GREAT LAKES REGION THROUGH THE SOUTHERN NEW ENGLAND/NORTHERN MID  
ATLANTIC COAST BY THE END OF THE PERIOD. THIS IS FORECAST TO BE  
ACCOMPANIED BY A DEVELOPING SURFACE LOW ALONG AN INITIALLY NORTHWARD  
ADVANCING WARM FRONT. IT IS ALSO EXPECTED TO CONTRIBUTE TO  
SUPPRESSION OF BROADER-SCALE RIDGING, INITIALLY PRESENT ACROSS MUCH  
OF THE OHIO VALLEY INTO MID ATLANTIC, BY THIS EVENING.  
   
..GREAT LAKES/OHIO VALLEY INTO MID ATLANTIC  
 
FORCING FOR ASCENT AND DESTABILIZATION ARE ALREADY CONTRIBUTING TO  
INCREASING THUNDERSTORM DEVELOPMENT ALONG THE FRONTAL ZONE ACROSS  
SOUTHERN PORTIONS OF THE GREAT LAKES REGION, AIDED BY A 30+ KT  
WESTERLY 850 MB JET. THIS ACTIVITY APPEARS LIKELY TO PROGRESS  
AROUND THE CREST OF THE LARGE-SCALE RIDGING, AND MAY SPREAD  
EAST-SOUTHEAST OF THE ALLEGHENY MOUNTAINS INTO PORTIONS OF THE MID  
ATLANTIC REGION BY THIS AFTERNOON. LIMITED LOW-LEVEL MOISTURE MAY  
ONLY CONTRIBUTE TO WEAK BOUNDARY-DESTABILIZATION ACROSS THIS REGION,  
BUT DEEP BOUNDARY-LAYER MIXING ALONG AND SOUTH OF THE WARM FRONT MAY  
CONTRIBUTE TO POTENTIAL FOR STRONG SURFACE GUSTS ACROSS NORTHERN  
VIRGINIA, AIDED BY MODEST WEST-NORTHWESTERLY MID-LEVEL FLOW.  
 
MEANWHILE, IN THE WAKE OF THIS ACTIVITY, WARM AND CAPPING ELEVATED  
MIXED-LAYER AIR IS FORECAST TO OVERSPREAD MUCH OF THE SOUTHERN GREAT  
LAKES AND OHIO VALLEY REGION. THIS MAY SUPPRESS CONVECTIVE  
DEVELOPMENT THROUGH MUCH OF THE DAY, BUT DAYTIME HEATING AND  
INCREASING LOW-LEVEL MOISTURE (INCLUDING SURFACE DEW POINT INCREASES  
THROUGH THE LOWER 60S), MAY CONTRIBUTE TO "LOADED-GUN" TYPE  
SOUNDINGS WITH CAPE IN EXCESS OF 1000 J/KG OVER A SIZABLE AREA.  
 
CONSIDERABLE SPREAD EXISTS AMONG THE VARIOUS MODEL OUTPUT CONCERNING  
THE POTENTIAL CONVECTIVE EVOLUTION WITHIN THIS ENVIRONMENT, WHICH  
WILL INCLUDE STRENGTHENING DEEP-LAYER SHEAR SUPPORTIVE OF ORGANIZED  
SEVERE STORM DEVELOPMENT WITH THE APPROACH OF THE UPPER IMPULSE BY  
THIS EVENING. HOWEVER, AT LEAST SCATTERED DISCRETE STORM  
DEVELOPMENT APPEARS POSSIBLE ACROSS SOUTHERN PORTIONS OF THE GREAT  
LAKES REGION BY EARLY EVENING. CONTINUED SOUTHWARD DEVELOPMENT OF  
AT LEAST SCATTERED DISCRETE STORMS APPEARS LIKELY ACROSS THE OHIO  
VALLEY THROUGH THIS EVENING, AHEAD OF A SOUTHWARD ADVANCING COLD  
FRONT IN THE WAKE OF THE SURFACE LOW.  
 
GIVEN THE ENVIRONMENT, STRONGEST STORMS WILL BE CAPABLE OF PRODUCING  
VERY LARGE HAIL, WITH AT LEAST SOME UPSCALE CONVECTIVE GROWTH  
THROUGH THE EVENING CONTRIBUTING TO POTENTIAL FOR DAMAGING SURFACE  
GUSTS. TORNADIC POTENTIAL REMAINS MORE UNCLEAR, DUE TO THE FORECAST  
VEERED NATURE OF THE LOW-LEVEL WIND FIELDS, AND RESULTANT LACK OF  
MORE PRONOUNCED CLOCKWISE TURNING WITH HEIGHT IN THE LOW-LEVEL  
HODOGRAPHS.  
 
EASTWARD ADVECTION OF THE CONVECTIVELY UNSTABLE THERMODYNAMIC  
PROFILES, EAST OF THE APPALACHIANS INTO NORTHERN MID ATLANTIC  
COASTAL AREAS IS FORECAST OVERNIGHT. THIS MAY OCCUR ABOVE A  
RESIDUAL STABLE LAYER NEAR THE SURFACE, BUT IT SHOULD CONTRIBUTE TO  
INCREASING SEVERE WEATHER POTENTIAL, AT LEAST IN THE FORM OF  
THUNDERSTORMS CAPABLE OF PRODUCING SEVERE HAIL.  
   
..LOWER MISSISSIPPI VALLEY  
 
MODELS SUGGEST THAT A PERSISTENT ZONE OF LOW-LEVEL WARM ADVECTION  
WILL SET UP ACROSS THE REGION BY EARLY TODAY. THIS PROBABLY WILL BE  
ACCOMPANIED BY INCREASING THUNDERSTORM DEVELOPMENT, WHICH MAY  
EVENTUALLY BECOME SUPPORTED BY INFLOW OF MODERATELY UNSTABLE  
BOUNDARY-LAYER AIR BY THIS AFTERNOON. ALTHOUGH LOW-LEVEL WIND  
FIELDS MAY REMAIN MODEST IN STRENGTH, MODERATE TO STRONG MID/UPPER  
FLOW AROUND THE CREST OF THE SUBTROPICAL RIDGING MAY CONTRIBUTE TO  
SUFFICIENT SHEAR TO SUPPORT A RISK FOR SEVERE HAIL AND STRONG  
SURFACE GUSTS.  
 
..KERR/GRAMS.. 04/07/2020

 

[Sydney Claridge]

Several of the CAMs have been consistently sending up isolated storms (some of which seem to grow into supercells) in the wake of the morning convection over central and southern Ohio in the afternoon hours.  The 06z NAM3K has also moved closer to the HRRR and seems to initiate a supercell in southeastern Ohio.  Although not a CAM, the RAP has also consistently suggested "popcorn" precipitation (possible storm cells?) developing in Ohio at the same general time. 

I am wondering if all of those models think that the morning convection will leave some sort of boundary behind?  While parameters seem better further northwest, the storms there seem to develop more readily into clusters, so if this verifies, portions of Ohio could become a focal point for significant hail and *possible* tornadic activity (the direction of the surface winds near this boundary will be a factor, if they are coming out of the SW rather than the W then isolated tornadoes could be an issue).  The HRRR suggests that the timeframe for this isolated convection to form would be around 18z near the Columbus area, and it is definitely conditional on the amount of subsidence and capping that is in place in the wake of the morning convection.  I do think that northern IN/OH and southern lower MI may be biggest risk areas for severe storms, although a diagonal strip from southern WI all the way the Delmarva will need to be watched.

[Sydney Claridge]

The boundary I mentioned in my prior post is quite evident on the 10z HRRR, extending from near Columbus OH to near Clarksburg WV.  The HRRR shows convective initiation in central OH (NW of Columbus) around this same time.  The model shows backed winds along this boundary (in some areas they are coming out of the south, although other models back the winds less).  There could be a window for a tornado or two if this verifies, provided convective initiation occurs and remains discrete (10z HRRR shows a few likely supercells in SE OH shortly after this), although T/Td spreads are quite large on the SW side of the boundary.

[OHweather]

Re: The Ohio afternoon stuff...can definitely see it as even the NAM soundings don't immediately build the capping inversion in this afternoon, and have a period of relatively uncapped CAPE.  Could definitely see a that boundary occurring due to clouds/rain to the east and sun/warmth to the south resulting in differential heating...but, with the only source of lift being that boundary and the window for this to occur being somewhat brief before the capping inversion does spread east, think it's only a couple of storms that go with a short window to do anything.  Storms would be supercellular given the shear so I could definitely see a large hail threat, but with a weak low-level flow and fairly short window think any tornado threat is still pretty low (but non-zero). 

[Sydney Claridge]

7 minutes ago, OHweather said:

Re: The Ohio afternoon stuff...can definitely see it as even the NAM soundings don't immediately build the capping inversion in this afternoon, and have a period of relatively uncapped CAPE.  Could definitely see a that boundary occurring due to clouds/rain to the east and sun/warmth to the south resulting in differential heating...but, with the only source of lift being that boundary and the window for this to occur being somewhat brief before the capping inversion does spread east, think it's only a couple of storms that go with a short window to do anything.  Storms would be supercellular given the shear so I could definitely see a large hail threat, but with a weak low-level flow and fairly short window think any tornado threat is still pretty low (but non-zero). 

Completely agreed, those surface winds are pretty weak so even getting a brief spin-up is going to be hard, and any such thing would have to be confined to the boundary itself given that LCL heights are pretty high just to the SW and temps are pretty cool just to the NE.  The main action will likely be with any activity that forms further northwest later on, particularly in northern IN and southern lower MI (and maybe northern IL though SPC has backed off on that; likely NW OH too).

[AWMT30]

If we can clear out here in MI today then game on! 

[Sydney Claridge]

SPC has now introduced a 5% tornado risk in the vicinity of the tri-point of MI/IN/OH.  15% hatched hail risk now extends northwest to Chicago, although areas further south (like Cincinnati and Indianapolis) have been removed from the hatched risk.

[CheeselandSkies]

Very odd. Orientation of the risk area makes it look like a northwest flow event. We like those in June/July, not so much in early April.

[Harry Perry]

Intriguing setup around these parts later this evening. Will be interesting to see it unfold.

[Jim Martin]

1 hour ago, BrandonC_TX said:

SPC has now introduced a 5% tornado risk in the vicinity of the tri-point of MI/IN/OH.  15% hatched hail risk now extends northwest to Chicago, although areas further south (like Cincinnati and Indianapolis) have been removed from the hatched risk.

 

[nwohweather]

I actually like the tornado chances in my old stomping grounds.  Great lapse rates and solid hodographs around that warm front is going to more than likely lead to a few tornado warnings across the Toledo/Fort Wayne areas this afternoon.  Lapse rates of 8 are unreal for Northern OH though, you could really see some explosive development and serious hail this afternoon.  

[purduewx80]

1 hour ago, CheeselandSkies said:

Very odd. Orientation of the risk area makes it look like a northwest flow event. We like those in June/July, not so much in early April.

You can already see the right-moving cells in WI on some of the longer composite loops. 

It appears all the differences in guidance for S WI and N IL come down to breaking the cap. Will have to watch that cell in WI even though it may move off the instability axis in the next hour or two. It will lay out a mesoscale boundary near the warm front that may also enhance a lake breeze and its associated convergence in east-central and southeast WI, for a potential initiation area.  It's hard to ignore the consistency of the ECMWF and HRGEM to initiate cells back near MSN, DBQ, RFD, but we definitely need to think about a strong cap holding things back today.

Mid-level lapse rates have been observed near 9C/km at OAX and DVN this morning: 

That plus a ~70KT mid-level jet forecast to overspread the region should allow for quick supercell development around 5-6PM - these will eventually grow upscale into that long, SE-moving squall line overnight.

 

[madwx]

not gonna lie these mid level lapse rates are bonkers.  would love to see this more often this spring/summer.

I think there a good chance for some 2"+ hail especially early on in the development from these storms.  

[geddyweather]

1 hour ago, nwohweather said:

I actually like the tornado chances in my old stomping grounds.  Great lapse rates and solid hodographs around that warm front is going to more than likely lead to a few tornado warnings across the Toledo/Fort Wayne areas this afternoon.  Lapse rates of 8 are unreal for Northern OH though, you could really see some explosive development and serious hail this afternoon.  

Definitely could be one of those "sleeper days" for sure. I don't feel like the hodos exactly scream TOR potential, but think if any development can stay relatively discrete, there's a decent shot at seeing something drop. 

More headline-worthy to me is the hail threat. RAP has a widespread SHIP of 2 for most of the region by 21z. Not gonna lie, I thought the lapse rates were maybe a bit overdone a bit earlier in the week, but seeing many meso models with 8.0-8.5 on the day of is nuts. Throw in a WBZ at what appears to be around 8000-8500ft and the vertical wind shear and I would not be surprised if we see several big stones around the area today. 

[IWXwx]

Enhanced Risk Incoming