9/21/05 NOW: WI/MI/MN

[nickgrillo]

Few severe thunderstorms now ongoing across in ne WI near the warm front. Obvious supercell to the north of Heshena... With large hail likely associated with it (>60 VILS) and given the favorable low-level and deep-layer shear across the area, I'd definitely wouldn't rule out a tornado or two associated with these storms...

 

[rdale]

With dew points only in the mid-50's, the LCL is nearly 7000ft and that'd be quite a tube to get down to the surface! Nice convergent rotation in some of those cells but I can't imagine there's going to be much TOR threat as the spin doesn't look very strong at all.

I want to know what sort of whopper of a fire is going on northwest of Milwaukee - the GRB radar shows what looks to be a massive smoke plume extending nearly 60 miles but I can't find anything on sat.

- Rob

 

[Andrew Khan]

Pretty strong convection in MN right now. Tornado and severe thunderstorm warnings active. I see rotation very clearly, and haail is absolutely there, with a VIL of 78, what can you expect. This is a very thin storm, almost a line segment. WI did indeed get hail, but nothing to worry about, tops being .50 in.

 

[nickgrillo]

I'd think even thou the LCLs are high invof the Sterns county storm... It's pretty much right on the warm front, therefore - I'd see it becoming more SFC based. Boundary layer is pretty unstable along/south of the front - with widespread 2000-3000 SBCAPE.

EDIT: Storm to the southwest of Sterns county has just been TOR-warned too... Very nice couplet/low-level mesocyclone apparent right between Willmar and Kandiyohi. Nice and isolated, too!

 

[Andrew Khan]

It's amazing to see how fast these storms can evolve. The storm that was far away, is now tornado warned. And the cell at the SW side, now has a meso-rotation with very high dBZ values. I think I am beginning to see a hook echo in Stearns county! Yes, I'm sure now it is! It has two meso rings on it, and a TVS. Nick, do you see the Hook?

 

[Chris Carlson]

Watching this one on radar. No reason for me to leave as it appears I will probably be in the middle of this one. Just as I write this, I'm hearing the tornado sirens going off. I'll report anything this happens here of course.

 

[Andrew Khan]

Four Tornado warnings currently active in MN, rotation is increasing, and is quite strong. I wonder if this will drop a tornado or two. There is a rotation-segment, thats tight it is 8.0 nm in diameter.

 

[nickgrillo]

* AT 610 PM CDT...RADAR INDICATED A STORM CAPABLE OF PRODUCING A
TORNADO...13 MILES WEST OF LITCHFIELD...OR ABOUT 12 MILES EAST OF
WILLMAR...MOVING EAST AT 30 MPH. THIS STORM HAS PRODUCE FUNNEL
CLOUDS NEAR ATWATER IN KANDIYOHI COUNTY.

I definitely would pay attention to the Kandiyohi-Meeker county storm... Nice strong, tight low-level mesocyclone near Grove City. I'd have to bet the funnel cloud reports from this thing are authentic...

 

[Andrew Khan]

Yes Nick, the Kandiyohi-Meeker county storm, is even developing a Hook Echo. How are you able to see a tight low-level mesocyclone?

 

[tom hanlon]

Very clearly a strong storm up there. Looks a little too close to what I assume would be suburban areas. Latest radar showed some weakening. Hope whatever tor happens to drop that it finds an uninhabited space and tears up only a field or two.

Doubtful that any other storms will get as strong and this one seems to be weakening. So maybe not today.

>edit<
One tor report so far so I guess my assumption above was not on target. Wonder if Chris got near that cell in time.

--
Tom Hanlon

 

[Chris Carlson]

Wow, this was very intense. Probably the most intense I've ever been in. I recorded 1 inch of rain but I'm guessing we got more. Just writing this my power has flashed twice but I'm on battery backup. Winds had to be at least 75MPH. I have some minor water damage for the first time ever. My sliding glass door couldn't take the wind and rain and water starting coming up out of my floor. This is only a 2 year old house. Some minor street flooding and tree damage. I haven't gotten out to survery my house but wouldn't be surprised to have some roofing missing. I could go on forever but just keep an eye on this one.

 

[Andrew Khan]

Wow, what a severe weather mess thi sis. This is a very very powerful storm system, and has dropped numerous funnels and has reports of a tornado on the ground, and, could still possibly be. It will be heading towards the twin cities if it is in fact on the ground. Rotation is EXTREMELY strong, and is generating new meso's/TVS' every second practically. Can we classify this as a Supercell? Wow, a hail report of 2.75 in, that's pretty big. There has also been some wind reports from this storm. I'd say this is a pretty dangerous situation. I hope someone will have pictures of this!

 

[Andrew Khan]

Wow, just wow......3 tornado warnings, 7 thunderstorm warnings, and now 4 flood warnings....this thing just keeps churning.

 

[Jeff Snyder]

Andrew,

I would say that the storm that approached and passed immediately north of the Twin Cities was an HP supercell, with a very strong, rain-filled RFD. The storms have now taken on the look of an MCS, so the tornado threat is diminishing with this cluster. Also -- it's relatively common to have meso and TVS indicators tripped for strong shear along MCS gust fronts. Such indicators do NOT usually indicate a tornado potential -- just horizontal shear along the gust front. Yes, you can get brief gustnado type activity along this area, but a TVS along the leading gust front of an MCS USUALLY doesn't represent the same hazard as a TVS in the updraft of a supercell...

Latest LSR:
0703 PM TSTM WND DMG ANDOVER 45.26N 93.33W
09/21/2005 ANOKA MN LAW ENFORCEMENT

THREE HOUSES DESTROYED...PEOPLE TRAPPED IN DAMAGED
HOUSES.

 

[Andrew Khan]

So it's no longer a supercell then, it's just an MCS? Why did the tornado threat die down here after?