6/19-6/23 Severe Weather Risk

[homedis]

can someone tell me their thoughts for my area (bloomington in) wednesday? from what i can tell i think i'm too far south/west

definitely on the southern edge. But you might still get in on some action

[HillsdaleMIWeather]

Watch is out.

[andyhb]

Some notes I have regarding this...

 

First of all, despite substantial capping in several setups this year, it seems that almost all of them have broken in some fashion, even with relatively neutral height falls or even slight height rises. Whether this speaks to a specific property of the EML this year or not, it seems that convective initiation has really not been much of a problem even in weakly forced setups. Although I will say, none of those setups had 110˚F+ temps in the SW prior to them.

 

Secondly, I am a bit concerned about a morning MCS coming through and dropping a surging outflow boundary that effectively cuts off the area of strongest dynamics from the best instability, although we've seen these things happen before where you have a strong LLJ that ends up partially overcoming this complication (see: 6/22 last year).

 

Finally, the risk to Chicago here is in my mind, very real. Given the low level trajectories S of the warm front, the lake breeze boundary is going to be a non-factor here for most of the metro assuming it doesn't get cut off destabilization early. That could viably leave the city is a perilous position very close to the warm front, with possibly extreme shear profiles in place. We've all seen what can happen when that sort of sweet spot develops...

 

Edit: Oh and I should also mention that almost every setup that has been expected to go linearly dominant this year has turned out to have more discrete cells than expected, just some food for thought.

[cyclone77]

Spc may push it east as well. Based on GFS and NAM solutions, We would be too far west to get in on the action. by 21z the low is located near IA/MN/WI border region limiting the westward extent that the spc has painted on current day 3.

 

IIRC the 6/12/13 event was modeled a bit too far to the east.  SPC ended up backing it to the west.  Sometimes these daytime strengthening surface lows slow up a bit relative to the models.  

[HillsdaleMIWeather]

IIRC the 6/12/13 event was modeled a bit too far to the east. SPC ended up backing it to the west. Sometimes these daytime strengthening surface lows slow up a bit relative to the models.

Of course the issue with analogs is every setup is different. 6/12 is the closest but this one has stronger shear and other differences

[cyclone77]

Of course the issue with analogs is every setup is different. 6/12 is the closest but this one has stronger shear and other differences

 

Agreed, but it's something I'll be watching out for lol.

[Stebo]

Some notes I have regarding this...

 

First of all, despite substantial capping in several setups this year, it seems that almost all of them have broken in some fashion, even with relatively neutral height falls or even slight height rises. Whether this speaks to a specific property of the EML this year or not, it seems that convective initiation has really not been much of a problem even in weakly forced setups. Although I will say, none of those setups had 110˚F+ temps in the SW prior to them.

 

Secondly, I am a bit concerned about a morning MCS coming through and dropping a surging outflow boundary that effectively cuts off the area of strongest dynamics from the best instability, although we've seen these things happen before where you have a strong LLJ that ends up partially overcoming this complication (see: 6/22 last year).

 

Finally, the risk to Chicago here is in my mind, very real. Given the low level trajectories S of the warm front, the lake breeze boundary is going to be a non-factor here for most of the metro assuming it doesn't get cut off destabilization early. That could viably leave the city is a perilous position very close to the warm front, with possibly extreme shear profiles in place. We've all seen what can happen when that sort of sweet spot develops...

 

Edit: Oh and I should also mention that almost every setup that has been expected to go linearly dominant this year has turned out to have more discrete cells than expected, just some food for thought.

As we discussed last night, this is a very good summation of my thoughts. With regards to the second point, if the morning MCS isn't as vigorous, a larger area would really be under the gun even into WI/MI. The thing that is interesting to me is the strength of the system, given that it is near 1000mb which is seasonally strong for this time of year. Another thing I would factor in with respect to the wind fields and instability, the potential would extend far into the night which is typical this time of year especially in situations of strong dynamics.

[Hoosier]

Some notes I have regarding this...

 

First of all, despite substantial capping in several setups this year, it seems that almost all of them have broken in some fashion, even with relatively neutral height falls or even slight height rises. Whether this speaks to a specific property of the EML this year or not, it seems that convective initiation has really not been much of a problem even in weakly forced setups. Although I will say, none of those setups had 110˚F+ temps in the SW prior to them.

 

Secondly, I am a bit concerned about a morning MCS coming through and dropping a surging outflow boundary that effectively cuts off the area of strongest dynamics from the best instability, although we've seen these things happen before where you have a strong LLJ that ends up partially overcoming this complication (see: 6/22 last year).

 

Finally, the risk to Chicago here is in my mind, very real. Given the low level trajectories S of the warm front, the lake breeze boundary is going to be a non-factor here for most of the metro assuming it doesn't get cut off destabilization early. That could viably leave the city is a perilous position very close to the warm front, with possibly extreme shear profiles in place. We've all seen what can happen when that sort of sweet spot develops...

 

Edit: Oh and I should also mention that almost every setup that has been expected to go linearly dominant this year has turned out to have more discrete cells than expected, just some food for thought.

 

 

You couldn't model the synoptic warm front in a more prime location for Chicagoland than where it is right now.  Anything discrete would have the potential to be a big problem. 

[Hoosier]

As we discussed last night, this is a very good summation of my thoughts. With regards to the second point, if the morning MCS isn't as vigorous, a larger area would really be under the gun even into WI/MI. The thing that is interesting to me is the strength of the system, given that it is near 1000mb which is seasonally strong for this time of year. Another thing I would factor in with respect to the wind fields and instability, the potential would extend far into the night which is typical this time of year especially in situations of strong dynamics.

 

 

GFS/NAM both have 925 mb winds around 50+ kts. on Wednesday evening/night.  Wouldn't take much to bring that down even well after dark.

[andyhb]

Still incredible soundings coming off the 18z NAM (and relatively early in the day too), with a larger area uncapped.

[Indystorm]

The late Tues/Wed. a.m. MCS location and trajectory seems to me to be the most important variable at present.for a set up that is quite perilous for the Chicago metro as modeled.

[hlcater]

DVN's thoughts. 

 

 

Wednesday...a challenging forecast for sure with much dependent on
what occurs Tue night convection-wise, and how fast the associated
convective debris and any outflow boundaries can clear as Wed
progresses. The incoming SFC wave and it`s path also very important.
Assessing the 12z model solutions, the GFS and especially the NAM
have are furthest north with the low pressure moving from west-to-
east acrs northeastern IA into far southern WI. The 12z ECMWF is
further south an moves the sfc low east generally along I80 toward
the Quad city area by 00z Thu. The NAM and GFS with their further
north placement essentially CAP off most of the CWA with warm wedge
of H7 MB air, and have explosive convection taking off just to the
north and northeast of the CWA by Wed evening. High shear and plenty
of thermodynamics suggest severe supercell storm development in these
areas by late afternoon with a large hail and tornado threat, then
congealing into a high winds producing MCS as it propagates acrs the
southern GRT LKS and toward the eastern OH RVR Valley. The further
south ECMWF would place the northern and especially northeastern
CWA/NW IL in and area of initial development late Wed afternoon and
early evening, then moving out of the area by late evening. Will
adjust POPs accordingly with highest in the northeast, and again
favor the ECMWF (with warm front or lingering outflow boundary
adjusted further south as a focus) with a Severe threat in the north
and northeast.

[chase_stormz]

Still incredible soundings coming off the 18z NAM (and relatively early in the day too), with a larger area uncapped.

 

Pretty scary stuff coming from the NAM forecast soundings for the past 24 hours. It honestly will come down to storm mode in my opinion and the exact location but your concerns for the Chicago burbs and metro are very real. I hope people have their safety plans in place just in case.

[andyhb]

The thing that strikes me compared to 6/12/13 is there is a much larger area of backed surface winds forecast with this one (not only restricted to the frontal zone). In the analog case, that was basically limited to an area very close to the warm front, although we still had a few sig tors in IA with that event.

[Hoosier]

Pretty scary stuff coming from the NAM forecast soundings for the past 24 hours. It honestly will come down to storm mode in my opinion and the exact location but your concerns for the Chicago burbs and metro are very real. I hope people have their safety plans in place just in case.

 

 

There's a large annual outdoor festival a couple towns over from me that kicks off on Wednesday.  It seems like there's usually a weather disruption at some point but I'm not sure the last time there was a potential severe threat of this magnitude.  I think they have somebody that monitors the weather though so that's good.

[chase_stormz]

There's a large annual outdoor festival a couple towns over from me that kicks off on Wednesday.  It seems like there's usually a weather disruption at some point but I'm not sure the last time there was a potential severe threat of this magnitude.  I think they have somebody that monitors the weather though so that's good.

 

The Cubs and Cards (Go Redbirds   ) have a mid-afternoon game Wednesday as well at Wrigley.

[A-L-E-K]

Twas a good run

[HillsdaleMIWeather]

Jesus god the 18Z NAM has widespread PDS TOR or nearly PDS TOR all night Wed.

[Stebo]

Jesus god the 18Z NAM has widespread PDS TOR or nearly PDS TOR all night Wed.

Yeah the potential would last long after dark with this one. Soundings are uncapped all the way to Ohio by morning.

[hawkeye_wx]

This will be the first event this entire season with both good instability and good shear available in my area.  At this point it is looking like an MCS will pass through eastern Iowa after 10pm Tuesday night.  We sure do get a lot of our storms at night.  The models have the system off to the east for the Wednesday re-fire.

[andyhb]

If that morning MCS comes through early enough, could be dealing with a situation where you have heated outflow boundaries (i.e. air mass character on each side of the boundary is not dissimilar) to act as additional foci for storm intensity/initiation in the afternoon.

[HillsdaleMIWeather]

18Z GFS: Looks a bit more  north. Chicago looks to get slammed then IN/MI/OH up to about north of Lansing. 

[knitwx]

There was damage in SO. Bend and Mishawaka In. when that line of severe storms blew through. There are trees and powerlines down in the South Bend Metro. Power is out for thousands of people and trees are down on Grape road, and Ironwood both major streets.

[nwohweather]

If that morning MCS comes through early enough, could be dealing with a situation where you have heated outflow boundaries (i.e. air mass character on each side of the boundary is not dissimilar) to act as additional foci for storm intensity/initiation in the afternoon.

This is what I was thinking it would do

[HillsdaleMIWeather]

If that morning MCS comes through early enough, could be dealing with a situation where you have heated outflow boundaries (i.e. air mass character on each side of the boundary is not dissimilar) to act as additional foci for storm intensity/initiation in the afternoon.

Just realized that as well, remember 7/1/14? 

[Radtechwxman]

Timing is crucial on this. The Tues night-Wed morning MCS will have a major impact on how Wed pans out. If the MCS clears too early and we get widespread clearing, those strong 850s will push that hot capped air mass far north. We almost want the morning convection sticking around through at least early to mid morning so the wf doesn't scream north

[Hoosier]

Afternoon LOT afd was pretty lackluster.  They mentioned the heavy rain threat but no discussion of severe prospects.

[Stebo]

Afternoon LOT afd was pretty lackluster.  They mentioned the heavy rain threat but no discussion of severe prospects.

Very strange considering they are in an ENH already...

[Indystorm]

Garden variety t storm here at Fortville now.  Svr warned ne of me.  Yes, I was surprised by that LOT AFD.

[andyhb]

Tornado warning for Ottawa, looks to be a supercell with a hook approaching the city from the W and fast.