6/07/10 FCST: KS/NE/CO/SD

[Greg Blumberg]

Normally when I wake up, I'll check the sounding data and other information before posting a forecast here, but it seems I woke up too early. Anyways, I'm gonna scratch that outflow boundary theory. The MCS line from last night that I posted is already down near Oklahoma by now. I will say that is a very impressive line though.

 

[Andrew Stoller]

Regarding LCL heights today - I think the issue might be mitigated by cooler temps north of the warm front - temps are progged in the low to mid 80s the further north you go towards the Cheyenne ridge, with temps near 90 along the front. So we could realistically see localized areas of 85 over 65-70 for temp/dew spreads.

Surface low looks to end up possibly further south and west today by 00z according to the RUC - placing it at or southwest of Denver by 00z. Initiation will likely take place as it usually does from Denver north into the Laramie range.

Two targets I'm looking at today - catch the initial storms around Cheyenne to Denver, or park in Big Springs, NE and wait for everything to mature as it comes off the Cheyenne Ridge. It seems like every time there's a setup like this, a big monster supercell organizes off the east end of the Cheyenne Ridge.

 

[Matthew Crowther]

There is a huge difference between the GFS and NAM regarding cap strength/700 temps- the GFS is much warmer at 700mb, if it is correct the KS/CO area will be shut out. This reminds me somewhat of June 6th last year- some people busted in NE Colorado because the cap was too strong down there- right now I am in Julesburg after yesterday and unless I see something different I will be inclined to play eastern WY or the panhandle- the RUC breaks out storms north of CYS by 00Z.

EDIT, meant June 5, 2009

 

[Adam Adkins]

I remember I busted june 6 last year on my first ever chase because of the cap over NE colorado. If it doesn't show any signs of eroding I will be staying put. However the RUC shows CAPE values over 5500 j/kg, which should be enough to break the cap.

 

[Michael O'Keeffe]

Looking at the 12z RUC it appears the cap will be very strong across all of KS and CO. It appears the only shot at daytime storms will be in SE Wyoming into the NE Panhandle. This area has great directional shear profiles, better upper level support, and good helicity values along the Cheyenne Ridge. The HRRR has a few nice storms firing around Cheyenne at 21z and tracking ESE into far NE CO and the NE Panhandle.

With that said I think there could be a few tornadoes today with any storm that can fire in the warm sector but it will be tough outside of a few areas.

 

[Adam Adkins]

It looks like the CAP will erode completely farther south near the palmer divide - but that brings into play how far north the warm front will be. The GFS is way north while the NAM is actually that far south.

 

[Mikey Gribble]

I really like the area along the southern Nebraska panhandle border with Colorado where LCL's are lower. A tornadic supercell is looking pretty likely in that area this afternoon IMO. I'd set up east of Cheyenne 40 miles or so if I could have my choice of targets. As it is though, we are running late so that may be out of reach for us. We just now got on I70 at Salina. We are going to be pushing it big time. I hate feeling like you are late all day. Its costed me a lot of tornadoes in the past and that very well may end up happening again today.

 

[Adam Adkins]

I am just concerned with CAP. The RUC shows a very strong cap throughout the afternoon. If it can be broken then we will have quite the show but if not it could wind up being just like june 6 of last year.

 

[Darren Addy]

Not too worried about the cap today. It looks hellacious early but notice the NAM depression in the 700mb temps in SE Wyoming pointing to the NE/CO border area by 21z:

and look how nice that area becomes by 0z (700mb temps):

an area that JUST HAPPENS to also have the best 0-1km EHI (at 0z):

My target area this morning began with a Sterling, CO to Kimball, NE line.
I think I'd narrow it to a LaGrange, WY to Kimball, NE to Brush, CO triangle (which is not as large as it sounds).

NAM's model skew-t for Kimball has an STP of 6.5 at 0z.

 

[Mikey Gribble]

here is a quick map I made for my blog. I think there is a pretty good chance for an isolated tornadic supercell to develop near Cheyenne and track east along the area I circled in red on my map. The cap shouldn't be too much of an issue up there. LCL heights are also managable. Farther south LCL heights are more of a concern, but I think a couple tornadoes are also possible with storms firing northeast of Denver. The WRF simulated radar product may have pegged the forecast today. There is a lot of consistency in developing two or three discrete storms between Cheyenne and Denver. I really want to make it up to the Colorado border with the NE panhandle, but that may not be happening since we are a little late. We are going to keep heading that way and hope for the best though. Good luck if you're out chasing today

 

[Bart_Comstock]

/!\ A word of caution to those chasing today. US Hwy 385 in Southern Yuma County, Colorado is down to one lane and requires a pilot car escort. Once south of Wray, Colorado be careful to not get caught off guard by a storm while trying to navigate the road construction. further more there is a spot a few miles north of Wray on 385 that also has a flager. /!\

So far I am thinking my initial target of Holyoke may be a tiny bit too far south east and now I am quickly trying to get farther NW towards Wyoming. I really think the cap will be overcome. The HRR has a nice cell coming out of Goshen County, WY at 22z. That is a bit early for when I wanted to see something like this as I am still a bit far south but I should be able to make it. Really just as others have pointed out I think the sweet spot will be along the CO/WY/NE Panhandle boarder. My new target is either Sidney or Kimball, NE.

For any new chasers out, do watch out for the poor road networks out there and make sure you be careful of data holes as well. Rely on your eyes first then your radar.