2015-05-10 EVENT: IA/IL/WI/MO/SD/MN/TX/OK/AR/LA

[Ben Holcomb]

The likely 2 day outbreak in the great plains will move northeast on Sunday, which looks to be quite the day in eastern Iowa according to the 12Z NAM. With the surface low bombing out as it heads northeast under very strong mid and upper level flow, dare I say Sunday has the looks of a third straight day of outbreak.

Forecast soundings in Eastern Iowa show 150m2/s2 0-1 SRH with cape values near 3000 J/KG by 1pm. Relatively steep mid level lapse rates (6.8-7) look to overspread northern missouri and eastern Iowa.

Early initiation seems likely in my mind, with storms ongoing by early afternoon and quickly intensifying. LCL and LFC levels are the same in pretty much all soundings I saw, which should have the tendency to lead to robust storm development.

 

[Dean Baron]

Mods, can we add SD and MN to the title?

Looks like there is decent tornado potential in northwest IA/southeast SD/southwest MN in close proximity to the low. Instability should be enough to get things going with CAPE around 2000 and nice 0-1 and 0-3 km helictites along the warm front. Surface flow is also very nice with backed 20-25 mph winds. 4km NAM has been showing an arcing band of storms stretching from southeast SD into northwest IA. Could be an early show too. Right now I would say Sioux City, IA as an initial target but that could move east or west. I think tomorrow could be a decent day.

 

[Josh VandenTop]

I've been watching the nw iowa/ ne Nebraska/ see south Dakota target for a few days now. Looking at nam it looks like we should get decent heating and moisture. Cape should be ample to get things going and with 40+shear in place I definitely see tornado potential, possibly even strong tornadoes with what I'm seeing now. I was unable to play today's set up due to commitments at home and living in Sioux Center it's looking like that might have worked to my advantage. As of now I'd agree with Dean, Sioux City by 1 will be my initial target.

 

[Brian McKibben]

MOD: Need to add Oklahoma and Texas too.

00z Nam now has the DL setup along I-44 in Oklahoma. This puts OKC Metro in play for tomorrow. Looks like there is still plenty of upper support in the southern plains too with 50+ kts at 500 hPa.

 

[Rob Gardner]

Leaving at 4:30 am, targeting Northwest Iowa. Based on latest runs of NAM / RAP, expecting initiation between 1 and 2, and looking to play the warm front, esp any storms that can get rooted on it. Motions look to be nice and slow on both models, moving ENE and easily right turning on to the front. Dew points look good, and it looks like the crapvection that was around today won`t be the same challenge in Iowa.. With dew points in the mid 60s, it at least feels like a typical Iowa setup... Anyone else seeing any negatives? I am 0-6 on Iowa chases. Hoping to break the streak tomorrow.

 

[Jeff Duda]

If I were to have left Norman today or be coming from Colorado yesterday, I'd be heading up towards the cyclone center in NE NE/SE SD to play with what may happen with the column being so damn cold and all that background vertical vorticity already in place. Moisture and instability don't look to be particularly outstanding, but I'm sure something interesting will happen there. The HRRRX wants to evolve/grow the current scattered convection in C KS and wipe out a good portion of W IA later on today, so I don't have much confidence in anything happening there.

If I were coming from the east, I'd think really hard about sitting on the warm front draped across C IL into S IA right now. A little better moisture quality than farther west, and more likely to refrain from clouding over, allowing for strong heating and destabilization as the day goes on. The wind profile right now is pretty ugly, and shear is quite weak, but I expect it will improve as the day goes on. Plus, it's a warm front, in Illinois, in May...

 

[Andy Berrington]

Damaging, fairly large tornado has already struck Delmont, SD. Houses and a church steeple reported "down" with injuries per scanner feed and via FSD.