2011-04-10 FCST: IA/MO/AR/LA/WI/IL/MN/OK

[Paul Sherman]

Latest RUC Breaks out a Nice looking Supercell in Northern and North Eastern Iowa which races to the NE At Warp Speeds.
Thought Below and Good Luck To Everyone Today - Much Tougher Chase Conditions.
http://plainschaser.blogspot.com/2011/04/sunday-april-10th-2011-chase-target.html

 

[Chip Redmond]

Convection is now progged to start late in the day with a cap holding out most the afternoon. Although this setup doesn't have a blue sky bust threat, after seeing at least 7 tors yesterday and the warm front going northward into bad terrain with incredible storm speeds, will sit this one out. Really wished convection would start early.

Chip

 

[Dan Robinson]

Short-term model guidance (HRRR, RUC) moves the surface low to Lake Superior by evening, with veered surface winds throughout Wisconsin and points south by the time convection fires.

 

[Bob Conzemius]

STATUS: GO
TARGET: Rice Lake

I don't think the hodographs are as good as yesterday, but deep layer shear and low-level shear (especially deep layer shear) look fine. I do like the lower LCLs farther north. Hell, maybe it will be a linear mess, but with that much shear, I don't think that linear, and even the July 27 linear mess managed to produce a few tubes in Wisconsin. Do worry about the flow becoming a little more veered, but with low deepening a bit, this shouldn't be preventative. Would like to have chased yesterday, but didn't have an early enough start (although I would have probably seen the last of the after-dark tubes), and I'm pretty convinced yesterday will end up being the better event, but I usually regret the shots I do not take.

 

[Scott Weberpal]

Not too concerned with the veered surface flow, 0-1km SRH >250 should get the job done - especially further south where the storms will have no issues remaining discreet.

Can't ignore the insane 0-1km helicity and CAPE combination today, and unfortunately that mean violent, fast moving tornadoes.

Heading to Madison after some obligations I have earlier in the day, then deciding from there whether to go west toward my favored target of Prairie du Chien, or northwest as the area around Eau Claire looks very good as well.

 

[Mike Johnston]

Short-term model guidance (HRRR, RUC) moves the surface low to Lake Superior by evening, with veered surface winds throughout Wisconsin and points south by the time convection fires.

Respectfully disagree, Dan. The RUC has precip breaking out over the main target area between 21 and 23z, during which time the low is still west of Lake Superior and there is still an area of backed surface winds over Wisconsin.

 

[Matt Hunt]

I am in general agreement with the SPC forecast once again today. I expect storms to fire south of Minneapolis at about 3-4 pm CDT and race off to the E/NE. It doesn't look like there is anything to trigger a line to the south until after dark. A strong cap will be in place through much of the day. If I were chasing I'd be targeting Eau Claire, WI. I wouldn't want to be too far south, or too far west with this one given the fast storm motions. This may be a day where you're better off to set up in a good location and let the storm come to you. Good luck to everyone chasing!

 

[Bill Schintler]

Chase Target for Sunday, April 10

Chase target:
10 miles south of Waterloo, IA

Timing and storm mode:
Discrete storms may develop ahead of a larger line of storms around 5 PM. Supercells will be likely with discrete storms, and storm motion will be towards the east-northeast at 50 mph.

Discussion:
At 12Z, the exit region of a 130kt H3 streak was approaching the upper-Midwest. Moisture is in place, with 12-13C H85 dewpoints noted over much of WI. The current visible satellite indicates an expanding SC field over MO and southeastern IA, with little vertical growth indicating the cap is still strong due to the EML. Dewpoints have climbed into the lower 60’s over much of IA, and most models except the NAM have initialized too high with LLVL moisture. Investigation of the WV loop indicates a subtle shortwave crossing KS.

At 21Z, the strongest UVM will be located over southwestern IA, where H7 omegas in excess of -10 uB/S will be present. Lesser lift will extend S across central IA. Also, H7 temperatures will cool several degrees between 21Z and 00Z, further weakening the cap. Storms should first initiate along a line from the Twin Cities south to Blue Earth, MN, between 3 and 4 PM. Storms should continue to build south, reaching Des Moines by 5 PM. It also seems possible that one or more discrete storms will initiate just south of Waterloo between 4 and 5. If this occurs,

- Bill Schintler
KD0DJG
www.twistertoursusa.com
12:31 PM CDT, 04/10/11