6/11/2010 FCST: CO KS NE SD IA MN

[jamesmseitz]

Been watching the dates around this for awhile now and find them very interesting and extremely tough to judge. There is a very definite warm front with great Cape, Lift and the cap eroding. KS the surface temps are through the roof a storm or 2 seems possible there as well so I included them. The shear seem to be ok at best, but what interests me about this day is the upper level winds curving to the right starting about Omaha up to the MN area.

Right now and the last few days the East NE, North IA and MN seem to be a play with the storms pulling away and either riding the warm front. The lack of movement from the front might help storms move off of it and begin to spin. CIN was disappearing by the 00Z Saturday time frame but the lack of Deep shear is troublesome but I have seem tornados in less. I have no doubt on big storms in the area but I realize that mode is a very real issue. I can't seem to wrap my head around the type of storms but I still think a chase is and will be in order.

 

[Rob H]

The Sioux Falls-Omaha axis and eastward across the MN/IA border looks interesting to me at the moment.

Kansas looked to be a marginal play based on some of the things you touched on - on the 6Z GFS, LCLs are easily over 1700m for much of the state and 700mb temps are 15deg or higher indicating a cap that probably won't break across KS and parts of NE/IA/MO. The 12Z NAM is showing a marked difference in surface temps in KS which would improve the odds of that play considerably. The NAM is also less aggressive in its placement of 700mb temps.

I like the hodographs in an area from the MN/IA border and traversing down through Omaha or thereabouts. While the majority of the lift is in KS/CO from that dryline/front, models are showing minor 700mb vertical velocity on the MN/IA border and near Omaha that might be enough to kick things up.

There is a demarcation of 30kt or greater bulk shear across NE/MN so it's feasible for some of these storms to fire up and organize into supercells once they move NE into better winds. The 12Z GFS has the bulk shear spreading into IA a little more.

 

[Andrew Stoller]

NW KS/Eastern CO look like good area tomorrow - most likely a convective outflow reinforced front will be backed into eastern CO into western KS. Trough and associated jet stream will finally be overhead, as will much cooler 700 mb temps (THANK GOD). Overall upper cooling much better Friday compared to the previous few days. Deep moisture will be in place with moderate instability and much better deep layer shear. Sustained surface based moist convection looks likely. I'd probably target the I70 corridor from Limon to potentially Oakley KS and go from there. NAM has big time CAPE and EHIs near Hill City by 00z with what looks like a monster supercell, so must keep an eye on that, but the EML looks to have moved into that area as well.

 

[Eian Greene]

NW KS/Eastern CO look like good area tomorrow - most likely a convective outflow reinforced front will be backed into eastern CO into western KS. Trough and associated jet stream will finally be overhead, as will much cooler 700 mb temps (THANK GOD). Overall upper cooling much better Friday compared to the previous few days. Deep moisture will be in place with moderate instability and much better deep layer shear. Sustained surface based moist convection looks likely. I'd probably target the I70 corridor from Limon to potentially Oakley KS and go from there. NAM has big time CAPE and EHIs near Hill City by 00z with what looks like a monster supercell, so must keep an eye on that, but the EML looks to have moved into that area as well.

Some of the Local Media outlets are already saying "moderate risk" of severe weather this afternoon, esp east of PUB. Norman has their 5% Tor area coming all the way back to the Rampart mountains of the Front Range, meaning anyone in COS might see something worth chasing fairly close to home if everything verifies...

Should I decide to go out chasing today, I'd target either A: a line NE from Calhan to Limon, or B: La Junta, CO and see where the sup's get their acts together at.
La Junta's looking like a good bet since their DP is sitting around 60 and Limon's is a hair over that.

Diurnal heating and a (and a few other factors) *should* add more instability instead of resulting in the last 2 day's setups busting for southern CO. (blame the 700Mb temps being too high and thus a strong capping layer killing any convection)

An obs that is worth tossing in there is... The NWS @ PUB is suggesting the best shear/instability on the Palmer Divide... Ala Jun 15,2009-ish event.

That said, you can't write off the Palmer Divide, since so many favorable setups and storm motions occur up there anyway, thus option A is looking pretty favorable, especially after 3-4 PM.

 

[Eric Bucsela]

Based on the latest RUC, I'm liking the space bounded approximately by LastChance - Burlington - Yuma. That area appears to have the best CAPE, low-level shear and pretty low LCLs. RUC initiates some storms in that region by about 22Z. BTW, I second Andrew's comment that it's nice to see reasonable 700mb temps for a change!