2026 Mid-Atlantic Severe Storm General Discussion

[Kmlwx]

5 minutes ago, yoda said:

Some bright sun and blue skies here and off to the west.  I think as long as we can get a good 4 to 6 hours of good heating it will be up to the boundaries and chance as you have stated 

I'm not sure I inherently "trust" any of the CAMs in setups like this. Even looking at all of them and taking an "average" can be off. 

I do think the HRRR (probably due to the fact that it's hourly) does tend to eventually latch onto something close to reality - but even then it can have times where it's sim reflectivity for 2 hours in the future doesn't even match reality. 

But yes - we shall see! Wouldn't be surprised if literally nothing happens locally today - but also wouldn't be surprised if there's a decent swath of 50-65mph wind across a good bit of the area. 

[Kmlwx]

The 13z SPC D1 outlook update still keeps us on the outside looking in. 15% well SW of the metro areas.

[Kmlwx]

The HRRR is pretty much nada now as well.

[Eskimo Joe]

12 minutes ago, Kmlwx said:

The HRRR is pretty much nada now as well.

Historically, we do not have multiple severe weather days in these parts. The radar trends in the Ohio Valley are not encouraging for those east of the Potomac River later today.

[yoda]

3 minutes ago, Eskimo Joe said:

Historically, we do not have multiple severe weather days in these parts. The radar trends in the Ohio Valley are not encouraging for those east of the Potomac River later today.

I'm more watching the N IL complex 

[Kmlwx]

7 minutes ago, Eskimo Joe said:

Historically, we do not have multiple severe weather days in these parts. The radar trends in the Ohio Valley are not encouraging for those east of the Potomac River later today.

Completely agree - the obvious answer here is that as repeated MCS activity rolls through - it pushes the overall boundary a little further south each time. Thus - the "train tracks" are more south vs yesterday. 

I think it CAN happen - usually MCSs on the SAME DAY suffer from this more - but it's definitely a factor even next day. 

I think what to watch for is if something to our SW can REALLY get going - perhaps it can throw off a cold pool just east enough to get some development on the "bookend" NW side. 

[SolidIcewx]

13 minutes ago, Kmlwx said:

Completely agree - the obvious answer here is that as repeated MCS activity rolls through - it pushes the overall boundary a little further south each time. Thus - the "train tracks" are more south vs yesterday. 

I think it CAN happen - usually MCSs on the SAME DAY suffer from this more - but it's definitely a factor even next day. 

I think what to watch for is if something to our SW can REALLY get going - perhaps it can throw off a cold pool just east enough to get some development on the "bookend" NW side. 

Those book ends can mean hella business. I remember one from may 2004. Southern tier of counties in MI got smoked at the 2pm hour. Was a kid at the time but those green skies and golf ball size hail were something else.

[Eskimo Joe]

Obvious derecho ongoing in northern Illinois. Multiple 80mph+ wind gusts.

[yoda]

14 minutes ago, Eskimo Joe said:

Obvious derecho ongoing in northern Illinois. Multiple 80mph+ wind gusts.

Warned for gusts to 100 mph now

[yoda]

Oh ok

Severe Weather Statement
National Weather Service Chicago/Romeoville
1108 AM CDT Tue Aug 11 2026

INC089-127-111645-
/O.CON.KLOT.TO.W.0075.000000T0000Z-260811T1645Z/
Porter IN-Lake IN-
1108 AM CDT Tue Aug 11 2026

...A TORNADO WARNING REMAINS IN EFFECT UNTIL 1145 AM CDT FOR PORTER
AND EAST CENTRAL LAKE COUNTIES...

At 1107 AM CDT, a severe squall line capable of producing both
tornadoes and extensive straight line wind damage was racing toward
Porter County at over 75 mph.

HAZARD...Tornadoes and wind gusts in excess of 100 mph.

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.

These dangerous storms will be near...
  Valparaiso around 1115 AM CDT.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

TAKE COVER NOW! Move to a basement or an interior room on the lowest
floor of a sturdy building. Avoid windows. If you are outdoors, in a
mobile home, or in a vehicle, move to the closest substantial shelter
and protect yourself from flying debris.

This cluster of thunderstorms is capable of producing tornadoes and
widespread significant wind damage. Do not wait to see or hear the
tornado. For your protection move to an interior room on the lowest
floor of a building.

&&

LAT...LON 4122 8697 4127 8706 4129 8712 4127 8719
      4124 8722 4162 8723 4163 8716 4165 8715
      4165 8710 4171 8693 4124 8693
TIME...MOT...LOC 1607Z 275DEG 59KT 4145 8727

TORNADO...RADAR INDICATED
MAX HAIL SIZE...0.00 IN

[Kmlwx]

It's heading pretty east for now - but these things tend to bend more and more SE with time. Additionally, I feel like subsequent linear MCS lines tend to go more south than the preceding ones. But worth watching how big of a bend to the SE it starts curving. If it's significant probably game over for storms for us. 

[WxUnit]

HRRR has been anticipating the southeast turn very shortly. If that doesn't happen, and it keeps chugging east we'll know it'll be a nowcast situation for this evening. Regardless these MCSs have been fascinating to watch so far. More then I can remember over the last day running over the same areas.

[Kmlwx]

15 minutes ago, WxUnit said:

HRRR has been anticipating the southeast turn very shortly. If that doesn't happen, and it keeps chugging east we'll know it'll be a nowcast situation for this evening. Regardless these MCSs have been fascinating to watch so far. More then I can remember over the last day running over the same areas.

One thing that SPC mentioned in the relevant mesoscale discussion for the ongoing potential derecho - is that the areas east and southeast are pretty well hindered by earlier convective activity. They seem to think this may reduce the threat as it heads ESE but also that new and stronger activity may form on the southern flank. This would be inline with the CAMs and would lead to probably nada for us. 

[WxUSAF]

27 minutes ago, Kmlwx said:

One thing that SPC mentioned in the relevant mesoscale discussion for the ongoing potential derecho - is that the areas east and southeast are pretty well hindered by earlier convective activity. They seem to think this may reduce the threat as it heads ESE but also that new and stronger activity may form on the southern flank. This would be inline with the CAMs and would lead to probably nada for us. 

The heaviest reflectivities are making a hard south turn to my eye

[Kmlwx]

Yep. Today looks mostly dead for us save for some overnight downpours here or there. 

[Eskimo Joe]

16 minutes ago, WxUSAF said:

The heaviest reflectivities are making a hard south turn to my eye

The morning convection removed any chances for severe weather in these parts. As SPC and @Kmlwxsaid, the atmosphere is largely capped and void of any meaningful surface instability.

[Eskimo Joe]

2 hours ago, yoda said:

Warned for gusts to 100 mph now

This probably will get classified as a derecho. Incredible stuff to witness today. One of the higher end wind events I've seen.

[Kmlwx]

1 hour ago, Eskimo Joe said:

The morning convection removed any chances for severe weather in these parts. As SPC and @Kmlwxsaid, the atmosphere is largely capped and void of any meaningful surface instability.

It's worse to our west (like WV). At least some sunshine has rebounded CAPE above 1000 in the metros seemingly. But still probably isn't going to do much. WV is devoid completely of CAPE 

[vortex95]

Yesterdays wind reports?...wow.   You'd think it was a bona fide derecho!  It wasn't, but the MCS areal coverage was very impressive NE to SW PA to VA.

Also, the classic DC split occurred, at least for CGs.  Take a look at the plot from later ydy.

There was an uptick on CGs in downtown Silver Spring after the line moved through N side of the city.  Saw some good CGs and heard some solid booming thunders to my S.

[Eskimo Joe]

4 minutes ago, vortex95 said:

Yesterdays wind reports?...wow.   You'd think it was a bona fide derecho!  It wasn't, but the MCS areal coverage was very impressive NE to SW PA to VA.

Also, the classic DC split occurred, at least for CGs.  Take a look at the plot from later ydy.

There was an uptick on CGs in downtown Silver Spring after the line moved through N side of the city.  Saw some good CGs and heard some solid booming thunders to my S.

Two observations:

1.) If there was more DCAPE, the wind reports from Berkley Springs, WV to just north of Annapolis would've been more impressive. Entirely possible that some 70-80 mph gusts would've even been capture on the Maryland mesonet. The Thurmont, Lisbon, and Clarksville sites were hit smack center by that northern cell.

2.) The lightning yesterday was impressive in my neck of the woods. Several positive lightning strikes that were quite brilliant to witness.