6/22/10 NOW:WY/SD/NE/MN/IA/IL/IN

[James Gustina]

Looks like a little CU field in northern Wyoming is deepening a little bit, along with storms attempting to pop up along an outflow boundary in Illinois going into Indiana. The third CU field is in southern Nebraska right now and looks a little bit deeper than those in Wyoming. I'd guess the pinpoint will be central Nebraska-ish as those explode in the 3000 j/kg of CAPE to the north.

http://w1.spc.woc.noaa.gov/exper/mesoanalysis/s13/1kmv/1kmv.gif?1277235215317

 

[Tim Marquis]

Looks like some CU is struggling in northern Iowa. 18z davenport sounding suggest a convective temp of 95. As of right now its around 88 across the northern part of the state. Looks like the cap is going to hold.

 

[James Gustina]

The cumulus field in Nebraska keeps trying but is having issues it would seem. That Colorado one exploded(as evident by the tornado warning).
http://w1.spc.woc.noaa.gov/exper/mesoanalysis/s13/1kmv/1kmv.gif?1277242093591

 

[Derek Weston]

Reportedly a large and dangerous tornado not too far NE of Fort Doge currently. (10:42 central) Clarion Iowa would seem to be potentially in the path of this storm.

Further west another tornadic supercell just a bit west of Fort Dodge.

LLJ kicked in and the storms erupted...

 

[Tim Marquis]

Looks like the cap held till the main vort moved in tonight. Storms are still descrete, I wonder when this will blob out into a MCS.

 

[Jeff Duda]

Looks like SPC failed again today. It's still a mystery to me how those storms in Iowa are doing that. I sat in the Council Bluffs to Missouri Valley, IA area for hours this afternoon watching vigorous CU turn to a few good updrafts then just *POOF* and die. Then suddenly after peak heating is gone, surface based storms suddenly erupt.

 

[James Gustina]

I'm amazed anything got started in Iowa myself. Looks like when this turns MCS/possibly derecho later on it'll nail Illinois in the dead of night.

I think they had one of the assistant mesoscale forecasters do it again today. I don't trust tomorrow's either. SPC forecasters are still great but they're having to let they're new people learn by trial and error i guess.

 

[Penny Lehner]

Drove a few miles north of Fort Dodge and witnessed the wall cloud. At that time I noticed no lowering but 10 minutes after I got back home, a large funnel was reported. Sirens have went off a couple times but they are quiet right now. Would love to be out in it but I have my 2 year old grandson and I won't put him in harms way just to see a storm. Standing on my back porch waiting right now as the circulation to the west is supposed to pass right over my house. The lightening is non-stop. A very interesting evening to say the least.

 

[matt doolittle]

Sitting right in the middle of the path of 2 separate cells. Reports are pouring in of tornados, funnels,wall clouds. It's getting CRAZY here.

 

[Rob Wadsworth]

My farm is in Storm Lake. So far, everything has passed it by. Gonna be a long night for me.

 

[Rean Clover]

Confirmed Tornado Marcus, Iowa

 

[James Hammett]

Looks like SPC failed again today. It's still a mystery to me how those storms in Iowa are doing that. I sat in the Council Bluffs to Missouri Valley, IA area for hours this afternoon watching vigorous CU turn to a few good updrafts then just *POOF* and die.

Me too, Jeff. As Derek mentioned it looks like the LLJ cranked up and they went to town. SPC had a 10% TOR up there all day but given how late they issued the TOR watch they must not have expected those cells to strengthen/sustain like they did.

 

[Jeff Duda]

Me too, Jeff. As Derek mentioned it looks like the LLJ cranked up and they went to town. SPC had a 10% TOR up there all day but given how late they issued the TOR watch they must not have expected those cells to strengthen/sustain like they did.

Let's not forget how they issued a tornado watch for C/E NE for no apparent reason, and that watch is now being replaced by a Severe Thunderstorm watch...

 

[Jason Bolt]

If a SVR watch is in place, then many TOR warnings or reports come in, why doesn't that watch get upgrades to a TOR watch?

 

[Jeff Snyder]

If a SVR watch is in place, then many TOR warnings or reports come in, why doesn't that watch get upgrades to a TOR watch?

It matters if the threat is expected to persist on the timescale of most watches (4-6 hours) over the spatial scales of most watches. Hindsight is 20/20, but it's not worth upgrade to a Tor watch if the threat is expected to be very isolated and/or short-lived. Considering a severe watch is already in place, and there exists a great likelihood for widespread non-discrete convection, it must have been deemed not worthwhile to cancel the existing watch in favor a new tor watch. Note that the latest MD mentions the tor threat that exists in northeastern Iowa (EDIT: see my EDIT below).

Despite nocturnal cooling, very high dewpoints (75-77 F widespread it seems) may give the storms some chance of remaining near-surface based. However, the trend has been away from discrete mode, so the tor threat may further diminish.

EDIT: This is what I get for not following the event too closely... There IS a tor watch in effect for north-central Iowa! See http://www.spc.ncep.noaa.gov/products/watch/ww0389.html . The counties under the tor watch WERE upgraded from Severe Thunderstorm Watch 388 a little less than 2 hours after 388 was issued. The watch graphic for T389 looks interesting, since the tor watch literally sculpts out the middle of Severe Watch 388.