6/16-6/18 Severe Weather

[KeenerWx]

To my dusty cobwebbed eyes, it looks like the threat may have modulated downward for much of LOT CWA. Window for recovery is fairly brief after morning to early afternoon convection.

[TheNiño]

Actually asking. What is the effect of the tropical storm going to have on this? It has to have some impact I feel like it’ll steal some energy, no? Nobody seems to be talking about it and I’m legit asking 

[Jackstraw]

2 hours ago, sbnwx85 said:

SPC not making many changes to the Day 1 forecast except extending the 10% tornado risk and CIG 2 north. There maybe more small changes but it’s too late to dig into it. A great read below.

Day 1 Convective Outlook  
   NWS Storm Prediction Center Norman OK
   1256 AM CDT Wed Jun 17 2026

   Valid 171200Z - 181200Z

   ...THERE IS A MODERATE RISK OF SEVERE THUNDERSTORMS OVER ILLINOIS
   AND INDIANA...

   ...SUMMARY...
   An outbreak of severe thunderstorms is expected today, with primary
   threat centered over Illinois and Indiana. Several intense
   tornadoes, swaths of damaging gusts over 75 mph and damaging
   wind-driven hail will all be possible.

   ...IL...IN...MO...OH...
   An intense mid and upper level jet will nose southeastward across
   the Midwest today, with a prominent leading disturbance moving out
   of IA and into IL through midday. Severe storms are likely to be
   associated with this early wave as a southwesterly low-level jet
   increases to 60 kt and rapidly bring instability into the area. This
   initial activity will bring damaging winds to eastern IA and
   northern/central IL. This system is expected to weaken later in the
   afternoon, but some remnants will move across IN. 

   Ahead of this early activity, a warm front will push north across IN
   and OH. New severe storm development, perhaps transitioning out of
   the remnant activity and/or forming near the warm front, is possible
   across northern IN into northwest OH. Shear profiles will be
   excessive, with tornado risk only conditional on minimal instability
   being present. The result may be a isolated tornadic supercells.

   To the west, the air mass across northern MO, IL, and into central
   IN will easily recover and rapidly destabilize due to strong
   southwest winds. A 60+ kt low-level jet is forecast, with notably
   strong winds around 700 mb as well (surface to 3 km shear values may
   exceed 60 kt). A plume of 65-70 F dewpoints will likely extend from
   central MO into IL and western IN in the 21-00Z time frame,
   contributing to 2000-3000 J/kg MLCAPE.

   A broken line of supercells is likely to develop and mature roughly
   from northern IN into central IL and MO around 21Z and spreading
   east/southeast through early evening. Given the clearly
   supercellular shear profiles, linear storm mode is unlikely for most
   of the event. Long-tracked supercells producing tornadoes and
   damaging hail are likely.

   Finally, the warm frontal position will need to be monitored near
   the IN/MI border. Even if instability is elevated into MI, extreme
   shear and lift may still yield damaging winds and even a tornado
   risk. As such, probabilities have been increased into far southern
   Lower MI.

   ...Upper TX Coast into the northern Gulf Coast...
   The NHC forecast shows Potential TC One moving into southwest LA by
   00Z. Wind fields associated with this system will strengthen out of
   the south ahead of it, resulting in areas of strong low-level shear
   from TX into southern LA, and possibly into MS. Mid to upper 70 F
   dewpoints will contribute to modest CAPE values, supporting embedded
   stronger cells with tornado potential.

   ..Jewell/Weinman.. 06/17/2026

 

Yep. They're really bullish on keeping the main event long tracked lines of sups with little consolidation. That surface low looks to do a good job of clearing out the brewing line in Iowa after it moves through later. 60+KT LLJ on some of the models is nothing to scoff at. Good long track sup setup its looking like between I70 an I80.

[Jackstraw]

4 minutes ago, TheNiño said:

Actually asking. What is the effect of the tropical storm going to have on this? It has to have some impact I feel like it’ll steal some energy, no? Nobody seems to be talking about it and I’m legit asking 

If it was bit stronger and a bit larger, yeah it could shunt the surface moisture flow into the OH Valley.  But I think its too little too late. It's already embedded into the established SW flow of the incoming trough over the conus and will like be absorbed into it. Not a non 0 effect but not as much as if it were stronger IMO. Crazy jet dynamics with the incoming trough, gonna be hard to overcome those.

[luckyweather]

3 hours ago, KeenerWx said:

To my dusty cobwebbed eyes, it looks like the threat may have modulated downward for much of LOT CWA. Window for recovery is fairly brief after morning to early afternoon convection.

haven’t read this am’s and yet but yesterday pm lot afd ack’d this and basically said the strength of the low may aide in overcoming this

 

[Chicago Storm]

G78MPH in Cedar Rapids with the bow.

[Torchageddon]

Another morning, another ripping bow echo at 8am in Iowa!

[metallica470]

5 minutes ago, Chicago Storm said:

G78MPH in Cedar Rapids with the bow.

Looking like some crazy winds on the south end of the bow as well with radar showing 100mph as also mentioned in the mesoscale discussion 

[Powerball]

No other place in this sub severe weathers like Cedar Rapids...

[hawkeye_wx]

Here, farther north in the city, we got 50+ mph wind as the severe bowing missed a hair south.  However, this is the second torrential comma head we've been under in the last week.

[WxWatcher007]

11 minutes ago, hawkeye_wx said:

Here, farther north in the city, we got 50+ mph wind as the severe bowing missed a hair south.  However, this is the second torrential comma head we've been under in the last week.

Saw a gust to 94 reported a little earlier to your west. How frequently do you guys get gusts 74+ out there?

[hawkeye_wx]

4 minutes ago, WxWatcher007 said:

Saw a gust to 94 reported a little earlier to your west. How frequently do you guys get gusts 74+ out there?

60 mph is pretty common in severe storms.  74+ mph is not super rare, but it's much less common.

[Chicago Storm]

Actually asking. What is the effect of the tropical storm going to have on this? It has to have some impact I feel like it’ll steal some energy, no? Nobody seems to be talking about it and I’m legit asking 

it’s over up north.

[hawkeye_wx]

I've received another 2.1" of rain this morning.  This puts June over 8".  We are really getting clobbered this month.

[cyclone77]

Don't think many anticipated the wind aspect to be as impressive as it was with the morning MCS out in Iowa.  The areas hit hardest had dews in the upper 40s/lower 50s shortly before being hit by it.  Very impressive.

Gonna get sort of some comma head action here, but no severe worries.  Think our severe threat is cooked here, as redevelopment later today will be south/southeast of the area.