6/19/10 FCST: KS/NE

[Andrew Stoller]

If the scorching 700 mb temps can be overcome, something big will likely pop from about Hill City, KS to perhaps Kearney, NE along the front that's going to be stalled out in that area. Moderate instability and potentially extreme EHI numbers are showing up run to run on the NAM, which does show precip breaking out by 00z. Unfortunately the GFS is buying into the cap and not breaking out anything. Looks to be some upper level energy still ejecting out from the west in the upper levels, which, along with frontal convergence, might overcome the cap.

It's all or nothing!

 

[Bill Schintler]

Chase Target for Saturday, June 19

Chase target:
Alma, NE (south central NE, near the KS border)

Timing and storm mode:
Storms will redevelop along a retreating outflow boundary. All modes of severe weather is possible, including a tornado or two. Storms will track towards the east at 30 mph.

Synopsis:
UA analysis indicates ridging over the Upper Midwest, with a shortwave departing the area over the western Great Lakes. Further west, height falls were occurring over the Four Corners area. Currently, an elevated MCS is tracking E along the NE/KS border. An attendant outflow boundary, currently along a line extending from Russell to Ness City, was tracking south at 20 mph. A moist airmass was in place along and south of the boundary, with dewpoints generally in the mid 70’s. The 12Z TOP sounding indicated moisture extending from the surface through 700mb.

Discussion:
Renewed convective development should occur along a retreating outflow boundary in north central KS, along the northern extent of a stout thermal ridge at 700mb. Once storms form, ample instability will coexist with impressive shear parameters. MLCAPE should increase to at least 3000J/kg. Enhanced clockwise hodographs will exist along and just north of the boundary, with SFC-3km SRH AOA 300m2/s2.

Bill Schintler
9:15 AM CDT, 06/19/10

 

[Mikey Gribble]

post from my blog...

We decided to chase today and left town an hour ago. Planning on heading west on I70 to Russel area and then heading north a tad. All depends on where the best surface convergence is setting up. I’m worried about dewpoints recovering in the wake of earlier convection. That could be a problem. The RUC has been very consistent in destabilizing the environment from west to east in the wake of morning precip. That is starting to look realistic as it is already underway. Whether or not thermodynamics will be favorable for tornadic supercells by late afternoon along the NE/KS border area remains to be seen. Its a Saturday and close to home so its worth a try.
Deep layer shear may be a bit of an issue too, but you never really know how storms are going to react in an environment with good low level shear and lower end deep layer shear, so all you can do is go and hope for the best. I will be streaming video this afternoon if you want to check it out.

 

[Mike Smith]

Haviland, KS profiler ( http://www.rap.ucar.edu/weather/upper/hvl_wp.gif ) is surprisingly favorable for supercells at 19Z. Winds are 60kt at 19,000 ft. with nice veering with height.

There are two boundaries. One boundary extends from Ft. Scott to Eureka to Wellington. A second extends from Eureka to Bazaar to Salina.

Water vapor satellite shows a weak impulse along the KS-CO border from Goodland to Elkhart with PVA-induced ACCAS from Ness City to SW of GUY.

SPC tools indicate 5000+j of uncapped 100mb MLCAPE from HUT to GBD!

I think Mikey's thinking of RSL as a starting point is pretty good. If the airmass is indeed uncapped in the face of the short wave, supercells could develop very rapidly in central Kansas. Over time, it may well evolve into a derecho (with extremely high winds based on instability and downdraft CAPE).

 

[Mikey Gribble]

Yeah I don't understand SPC's thinking at all with this afternoons setup. I must be missing something, because the atmosphere looks absolutely primed for supercells this afternoon if the RUC is to be believed, which so far all indications are that it is on track with this one. We are heading from Russel over to Hays right now. Nice CU fields starting northwest of here. It looks like that weak storm that moved through a few hours ago may help enhance convergence.
I am absoutely baffled at why they don't drag the severe probabilities a little farther south and at least make a mention of tornado potential in the latest forecast. I have to be missing something major here.

 

[Eric Bucsela]

Yeah I don't understand SPC's thinking at all with this afternoons setup. I must be missing something, because the atmosphere looks absolutely primed for supercells this afternoon if the RUC is to be believed, which so far all indications are that it is on track with this one. We are heading from Russel over to Hays right now. Nice CU fields starting northwest of here. It looks like that weak storm that moved through a few hours ago may help enhance convergence.
I am absoutely baffled at why they don't drag the severe probabilities a little farther south and at least make a mention of tornado potential in the latest forecast. I have to be missing something major here.

It looks great to me too. The EHI's and LCL's on the 20Z RUC seem perfect for tornadic supercells, and the cap seems breakable - obviously since we have initiation now in N Cntrl KS. We'll see how it plays out. Good luck to those of you luck enough to be able to chase today.