2017 Spring/Summer Severe Wx Thread

[Tom]

Latest 12z GFS run highlighting the same areas getting pounded by strong/training storms overnight Friday...nocturnal jet in full effect...

 

 

 

http://www.tropicaltidbits.com/analysis/models/gfs/2017072012/gfs_mslp_pcpn_frzn_ncus_7.png

 

http://www.tropicaltidbits.com/analysis/models/gfs/2017072012/gfs_mslp_pcpn_frzn_ncus_8.png

 

 

 

http://www.tropicaltidbits.com/analysis/models/gfs/2017072012/gfs_apcpn_ncus_10.png

[St Paul Storm]

Awesome Loop of last night's storms. Check out those mesocyclones.

 

https://twitter.com/NASA_SPoRT/status/888058189912080385/photo/1

[Tom]

18z High Rez NAM coming in hot for Fri-Sat...

 

http://www.tropicaltidbits.com/analysis/models/nam3km/2017072018/nam3km_mslp_pcpn_frzn_ncus_36.png

 

http://www.tropicaltidbits.com/analysis/models/nam3km/2017072018/nam3km_mslp_pcpn_frzn_ncus_39.png

 

 

 

18z NAM...

 

http://www.tropicaltidbits.com/analysis/models/namconus/2017072018/namconus_apcpn_ncus_18.png

[Tom]

MKX's take on heavy rain potential...

 

http://www.weather.gov/images/mkx/wxstory/Tab2FileL.png

[bud2380]

man, the same spots keep getting hammered.  Reminds me of winter.  At least we have received some moderate amounts of rain down my way, but we could use a little more still.  

[Niko]

Dry is the key word here. Turned on my Sprinklers as my grass is turning a little brown. Mother nature is not providing. Maybe tomorrow SEMI will get some juicy storms! Dry air on the way for next week. So far, yesterday was the first time my area hit the 90s this month, WOW!

[Tom]

00z NAM 3km hammers S WI...

 

http://www.tropicaltidbits.com/analysis/models/nam3km/2017072100/nam3km_apcpn_ncus_19.png

[Tom]

Both NAM models have shifted the heavy rain band south and keeps the action where it has been firing up.  Here are both 12z runs...

 

http://www.tropicaltidbits.com/analysis/models/nam3km/2017072112/nam3km_apcpn_ncus_9.png

 

http://www.tropicaltidbits.com/analysis/models/namconus/2017072112/namconus_apcpn_ncus_9.png

[Tom]

Latest HRRR run pretty much agrees with the NAM...

 

http://www.tropicaltidbits.com/analysis/models/hrrr/2017072113/hrrr_ref_frzn_ncus_12.png

 

http://www.tropicaltidbits.com/analysis/models/hrrr/2017072113/hrrr_ref_frzn_ncus_15.png

 

 

http://www.tropicaltidbits.com/analysis/models/hrrr/2017072113/hrrr_ref_frzn_ncus_17.png

 

 

http://www.tropicaltidbits.com/analysis/models/hrrr/2017072113/hrrr_apcpn_ncus_18.png

[Tom]

HRRR picking up on a secondary band that crushes CR area...

 

http://www.tropicaltidbits.com/analysis/models/hrrr/2017072114/hrrr_apcpn_ncus_18.png

[Tom]

Flooding potential is not looking good for N IL...

 

[Tom]

As was the case with last weeks event, models are shifting south with the corridor of strong/training storms and N IL is in the hot zone once again.

 

 

 

 

 

Based on what I'm seeing, this will be an interesting evening for a lot of IA/IL posters...WI posters borderline....

 

Run after run, HRRR keeps showing 2-4"+ over N IL...

 

http://www.tropicaltidbits.com/analysis/models/hrrr/2017072117/hrrr_apcpn_ncus_18.png

[Tom]

IA folks about to get a either a Severe Thunderstorm or Tornado watch soon...

 

http://www.spc.noaa.gov/products/md/mcd1380.gif

[Tom]

Courtesy from Skilling:  Does this heavy rain corridor look familiar???  That would suck for the DP and Fox River's...

 

 

 

[Tom]

@ Jaster/WestJim, you guys are not out of the woods!

[St Paul Storm]

Not warned at this point, but that cell headed for Rockford looks interesting. Gonna head right down I-90.

[Tom]

Not warned at this point, but that cell headed for Rockford looks interesting. Gonna head right down I-90.

Been reading its SWS's and it has been producing torrential rains. I got a bad feeling he rivers are going to all be screwed in N IL. Another major flooding event?

[St Paul Storm]

Been reading its SWS's and it has been producing torrential rains. I got a bad feeling he rivers are going to all be screwed in N IL. Another major flooding event?

My wife and son just landed at O'Hare. Glad they got in before the storms hit this evening. Northern LOT gonna get pounded with flooding rains again it appears.

 

That warned cell in ND at 70k ft?? Skies finally clearing here. Unfortunately too little too late. The clouds from this morning appear to have ruined another great severe setup.

[Niko]

Good shot of Thunderstorms late tonight into tomorrow morning in SEMI. Hopefully, we get drenched.

[Tom]

Wow...Tennis ball sized hail...

 

 

 

Severe Thunderstorm Warning Severe Weather Statement
National Weather Service Chicago/Romeoville Il
448 PM CDT FRI JUL 21 2017

ILC031-043-212230-
/O.CON.KLOT.SV.W.0134.000000T0000Z-170721T2230Z/
DuPage IL-Cook IL-
448 PM CDT FRI JUL 21 2017

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 530 PM CDT
FOR NORTHEASTERN DUPAGE AND NORTHWESTERN COOK COUNTIES...

At 448 PM CDT, a severe thunderstorm was located over Schaumburg,
moving east at 25 mph.

HAZARD...Tennis ball size hail and 60 mph wind gusts.

SOURCE...Radar indicated.

IMPACT...People and animals outdoors will be injured. Expect hail
damage to roofs, siding, windows, and vehicles. Expect wind
damage to roofs, siding, and trees.

[Tom]

Thunderstorm Watches hoisted for all of N IL and most of E IA...

 

Tornado warned cell popped up just south of CR near Iowa City...I think we have a member near there...

 

 

 

Tornado WarningSevere Weather Statement
National Weather Service Quad Cities IA/IL
459 PM CDT FRI JUL 21 2017

IAC103-212245-
/O.CON.KDVN.TO.W.0048.000000T0000Z-170721T2245Z/
Johnson IA-
459 PM CDT FRI JUL 21 2017

...A TORNADO WARNING REMAINS IN EFFECT UNTIL 545 PM CDT FOR CENTRAL
JOHNSON COUNTY...

At 459 PM CDT, a severe thunderstorm capable of producing a tornado
was located near Kalona, or 11 miles southwest of Iowa City, moving
east at 15 mph.

HAZARD...Tornado and golf ball size hail.

SOURCE...Radar indicated rotation.

IMPACT...Flying debris will be dangerous to those caught without
shelter. Mobile homes will be damaged or destroyed. Damage
to roofs, windows, and vehicles will occur. Tree damage is
likely.

[Tom]

Western burbs by my place getting crushed by a severe cell producing 1.25" hail...

[Hawkeye]

I'm not really liking the trend.  The southern Wisconsin and eastern Iowa convection should link up and blast northern Illinois over the next several hours.  The HRRR shows this well.  From CR west, there's still nothing popping.  The HRRR now delays development back to central Iowa until later, with just a narrow tail of convection passing over a lucky few.  The main show should be east.

[St Paul Storm]

Hoping the storms that fired in ND and N MN hold together as they pivot SE. The atmosphere seems to be recovering here in the Twin Cities as the skies cleared around 3:30. This may be a sneaky MCS developing that the models missed due to the earlier convection. Long shot....but we'll see.

[Tom]

Major flooding and wind damage from that cell...

 

 

 

[Tom]

Initial reports even suggesting a microburst hit the area...

 

 

 

 

 

[Niko]

And....here is my thunderstorm potential from NOAA:

 

Hazardous Weather Outlook

Hazardous Weather OutlookNational Weather Service Detroit/Pontiac MI353 PM EDT Fri Jul 21 2017MIZ047>049-053>055-060>063-068>070-221030-Midland-Bay-Huron-Saginaw-Tuscola-Sanilac-Shiawassee-Genesee-Lapeer-St. Clair-Livingston-Oakland-Macomb-353 PM EDT Fri Jul 21 2017This hazardous weather outlook is for locations along and north of M-59..DAY ONE...This Afternoon and TonightThere is a chance of thunderstorms late tonight. These storms are notexpected to be severe, but will be capable of producing heavyrainfall.  Storm motion will be east at 30 mph..DAYS TWO THROUGH SEVEN...Saturday through ThursdayThere is a continued chance of thunderstorms on Saturday and Sundaywith the best chance Saturday morning. The storms on Saturday are notexpected to be severe. An isolated marginal severe storm is possibleon Sunday as a cold front tracks through..SPOTTER INFORMATION STATEMENT...Spotter activation will not be needed today and tonight.

[St Paul Storm]

Holy wow, Tom. Thanks for sharing. The wife is in Downer's Grove and she says nothing is happening there....yet.

[BrianJK]

Holy wow, Tom. Thanks for sharing. The wife is in Downer's Grove and she says nothing is happening there....yet.

 

That nasty cell just barely brushed my area.  The Downers area and anywhere south probably got a few drops at best.  Radar is pretty well lit to the west, so this evening may be quite active.

[Tom]

That nasty cell just barely brushed my area. The Downers area and anywhere south probably got a few drops at best. Radar is pretty well lit to the west, so this evening may be quite active.

Yup, training signature evident in radar. Someone will get 6"+ total by tomorrow am

[Tom]

While you guys out in the Midwest are getting a taste of severe wx, out here, albeit it rather minimal comparatively speaking, I just experienced a storm that blossomed out of nowhere right above my place and had a mini micro-burst with some dust out ahead of it.  It literally formed right overhead.  I've never had that experience before out here.

[St Paul Storm]

Severe thunderstorm watch now extended south to the very northern outskirts of the TC metro. That line is holding its own. Nothing better than a midnight squall line. It's expected to weaken but we'll see. Bring it.

[BrianJK]

Its wild to see the multiplie individual cells within the cluster all doing their own thing.

[Tom]

Not good....not good...hearing radar estimates out west of 2-3"/hr...

 

[Tom]

Significant wind damage all across the western burbs and lots of hail reports from that super cell...

 

 

 

 

[St Paul Storm]

LOT radar looks like a Christmas tree right now with those colors. Daymn! Good luck and be safe all.

[Tom]

HRRR continues to pummel N IL with a secondary plume of moisture after 1:00am...6"+ totals are becoming more likely...

[Tom]

IA folks not out of the picture yet...latest SPC Mesoscale discussion talking about some possible storm development later tonight...

 

 

 

Farther west across IA, there is some concern that a strengthening
southwesterly LLJ will initiate new convection atop reinforced
outflow late this evening. If this occurs large hail could become a
concern with elevated storms across this region.

[Hawkeye]

Northeast Iowa convection blowing up again.

[St Paul Storm]

N IL is in for a long night with that new stuff around Dubuque and Decorah, IA. Never-ending training. The nighttime LLJ doing work.