2014-06-27 FCST: NE/KS/SD

[Royce Sheibal]

Been quiet lately, thought I'd throw out a forecast for you all to consider. It's awfully late in the season, but NW KS and C NEB are still climatologically favorable for tors and even sig tors.

The GFS brings the shear quite a bit further north and east than the NAM for friday. Based on GFS output, I'd say we're looking at broken bow up to norfolk as prime supercell formation. However, the GFS has been WAY too fast last few days, so perhaps we'll take a look at the NAM. The nam is holding shear and initiation way back into NW KS up to north platte and valentine. This seems like the most likely scenario, and the SPC has put out a 30% hashed area that supports this. May get moderate tomorrow?

I'd like to see what the RAP puts out tomorrow morning before i'd pick a final target, as it was pretty accurate at predicting the 6/16/-6/18 supercell formation. With bulk shear in the 40-50kt range, insanely high LI, and good moisture convergence, it would not be a surpise to see a few tors.

Update: West Central Neb around North Platte down to Dodge City is looking really promising for isolated tors. Anyone take a look at Sunday? I think we could see a major event in NE/IA/KS/MO.

 

[Taylor Wright]

I keep thinking there's no way we can get another trough out of the season, but here I am pleasantly proven wrong again.

A nice neg. tilted trough crashing into the central plains with a sharp dryline forecast in western Kansas. Unlike previous setups I've eyed in Kansas recently, the NAM has winds backed along the dryline. I've noticed negatively tilted troughs tend to over-perform despite weak flow aloft. With only 30-40 kts of 300 mb winds forecast by the NAM, this is an issue, but I'll think I'll stay south where the streak can maybe poke in a little bit. CAPE is above 3000, and shear should be sufficient for supercells.

The biggest problem about this setup is that it's on a Friday, which means I'll have to fly west after I get off at 4 pm, carefully driving the speed limit, and I'll have no choice but to go for the southern target around Dodge City and hope I don't miss the show. I'll also be without reliable data. LCLs aren't great down there, but if dews can stay in the mid or upper 60s this problem might solve itself. 300 mb winds aren't as backed down there south of the warm front.

I'm going to go out on a limb and say tomorrow will over-perform, given the history of negatively tilted troughs.