Jump to content
  • Member Statistics

    Total Members
    Most Online
    Newest Member

June 20th, 2021 Severe Weather Event


Recommended Posts

2 hours ago, Chicago Storm said:

Could envision a moderate risk being needed if guidance up until this point remains consistent.


you thinking wind or tornadoes?

If tornadoes, that's bold. I could see wind though. Storms moving out of Iowa later tomorrow evening should organize into a robust QLCS of sorts.

Link to comment
Share on other sites

Models looked a lot better for this 12 hours ago. Looks more unorganized/isolated in regards to severe. Have lots of dense fog in the area that has to manage to burn off before mid/high level clouds from lasts nights MCV moves in. Don’t know how we’re going to make it to 89° today under cloudy skies. I would expect isolated supercells initiating around 5-6pm along or south of I-94. Best threat looks to come south of the MI/IN/OH border. Couple of latest HRRR runs show a nice bow blowing through that way.


If we can somehow manage to get some better  instability then obviously the threat would be greater.  

Link to comment
Share on other sites

The NAM has come in and reversed a bit of the bleeding that was happening on guidance last night.

Would suggest a quality threat with the MCV from the Chicago metro into SW MI and N IN during the mid afternoon through early tonight. Then it has a sig environment in E IA and NW IL during the evening and into early tonight.

The cloud cover and precip shield with the hurricane over IA this morning has been steadily fading, with a good deal of clearing already across MO and C/S IL. Everything seems to be on track for now.

Link to comment
Share on other sites

Definitely seems like the ongoing MCV will be a big focus today.  Convection continues to bubble up nicely from central IA down into especially northern MO.  Would imagine that to hold it's own for several hours and eventually increase and become severe later today.  Any place ahead of that feature is in play for today, just depends how soon it takes off and starts producing severe.  Definitely could see some tor potential with that.

Behind it with the cold front is definitely looking pretty good as well.  Very nice synoptic setup for a band of severe with that.  How strong that gets depends on how much Iowa destabilizes later today.  Clearing already working into western IA already.  SPC meso shows steep mid LR out over the Plains, and those will shift into IA later today which will also help.  Forecast soundings show pretty good low-level shear and nice vorticity advection with the potent incoming vort max is nice as well.  HRRR has showed isolated cells popping up ahead out in the open warm sector which may be another good sign.  

All in all should be an interesting day.

Link to comment
Share on other sites

There are several boundaries out there that will mark the northern extent of the severe threat w/ the 2 MCVs, but the eastern-most boundary/front will likely lift a bit north of where it is now as long as clearing continues. The smaller/secondary MCV over MO is probably what will drive the wind/tornado threat across the southern Chicago metro (initiation of sfc-based TS near intersection of an outflow boundary and the lake breeze) into the Detroit area, likely reaching a peak either side of the IN/OH/MI borders. A good chunk of IA is definitely in play, with hail too, especially where the outflows intersect the low/front later on.1844826609_ScreenShot2021-06-20at10_25_06AM.thumb.png.1f5ac51851b5222ef1ff1038ed2fa9d1.png

  • Thanks 1
Link to comment
Share on other sites

4 minutes ago, hlcater said:

Made the decision to forego the MCV in favor of the front in eastern Iowa. Let's see how well that ages....

Could have played both, that's my current plan.

I'm off work from ORD at 2. Guessing by then somewhere in the Ottawa-Pontiac-Kankakee area might be in play with the MCV. Will chase around there for a while before hauling west to the IL/IA border. IKK to DVN can be done in 2hrs and 30mins, and with it light out till 9 now, it's doable. 

  • Like 2
Link to comment
Share on other sites

Just now, Chicago Storm said:

Could have played both, that's my current plan.

I'm off work from ORD at 2. Guessing by then somewhere in the Ottawa-Pontiac-Kankakee area might be in play with the MCV. Will chase around there for a while before hauling west to the IL/IA border. IKK to DVN can be done in 2hrs and 30mins, and with it light out till 9 now, it's doable. 

I still could. Debating it. I just worry that playing the MCV puts you out of position for storms in Iowa and you end up missing both.


I think there's tornadoes from the MCV, but I also think Iowa has a shot to maybe do something better, along with some regional bias 

Link to comment
Share on other sites

Mesoscale Discussion 1032
   NWS Storm Prediction Center Norman OK
   1057 AM CDT Sun Jun 20 2021

   Areas affected...far southeast IA...far northeast MO...much of
   central into northern IL...northwest IN

   Concerning...Severe potential...Watch likely 

   Valid 201557Z - 201800Z

   Probability of Watch Issuance...80 percent

   SUMMARY...A watch will likely be needed for parts the mid MS Valley
   across IL and into northwest IN.  Storms are expected to develop,
   intensify, and pose a severe risk as they move from near the
   IL/IA/MO border east-northeast across IL to the southern shore of
   Lake MI during the afternoon and early evening.  Convective trends
   will be monitored through the late morning and into the midday hours
   for an eventual likely watch issuance.

   DISCUSSION...Radar mosaic late this morning shows a series of MCVs
   located from northeast IA, central IA, and northern MO moving east. 
   Visible satellite shows a growing thunderstorm cluster across
   northern MO associated with the southern-most MCV.  Surface analysis
   places an outflow boundary from northeast MO east into central IL. 
   South of the boundary, southerly surface winds and temperatures in
   the lower 80s with dewpoints near 70 deg F are noted as of 10am
   observations.  North of the boundary, cloud debris has tempered
   surface heating with temperatures ranging from the mid 70s from a
   Quincy to Peoria line and lower 70s over northern IL.

   Model guidance varies considerably regarding the details of
   potential convective evolution across central and northern IL this
   afternoon.  As a result, there is relatively large uncertainty. 
   However, timing of the MCV and its eastward translation would lead
   to the potential for storm development and a corresponding risk for
   severe as it progresses east across the middle MS Valley.  Forecast
   sounding show moderate destabilization across central IL by early to
   mid afternoon (2000-2500 J/kg MLCAPE).  Equally important, the low
   to mid-level flow fields strengthen and forecast hodographs enlarge
   during the mid to late afternoon.  Consequently, it seems the risk
   for organized severe storms (including bows or supercells or mix
   thereof) and the associated severe hazards will increase coincident
   with this wind field response.  Due to the large spread in possible
   solutions for this forecast, observational trends will
   disproportionately weigh in the decision of a potential severe-storm
   watch issuance.

   ..Smith/Hart.. 06/20/2021



Link to comment
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now

  • Recently Browsing   0 members

    No registered users viewing this page.

  • Create New...