6/6/09 FCST: NE/CO/KS/OK

[Mikey Gribble]

With the models going back and forth with every run I won't believe anything until the last minute. I'll try to make my final decision with the 12Z or maybe the 00Z tomorrow and verify pulling the trigger with current obs on Saturday morning, but I trust all of these models about as far as I can throw them right now.
I've like Hebron all day, but with the capping issue I thought the safer bet was to move a little farter west. Here is my forecast from earlier btw http://loadedgunchasing.com/blog1/

 

[Melanie Metz]

Yes, H7 temps at 10C aren't too bad. And of course, never make any final decisions until that morning with latest runs and real surface obs! Which is why I don't spend too much time analyzing the 72 or 48 hr much. But at least we see potential! That's enough to get me on the road after work Friday.

 

[Mikey Gribble]

Here is a link to my forecast for Saturday. I am going to target the dryline some place between I70 and the Nebraska border. I explain my thinking in my forecast, which isn't real extensive, but I think there is a good shot of a storm or two breaking the cap over central and northern Kansas.
It basically comes down to a compromise. You have stronger and more backed 850mb winds south of I70, but the cap is stronger. North of I70 the 850 winds start to veer and weaken and continue to do so the farther north you go, so I want to get on the farthest south storm I can.

It's one of those cheat downstream days because it is a lot easier to catch a storm coming at you than to catch one that is going away from you. Here is my forecast http://loadedgunchasing.com/blog1/

 

[Chad Cowan]

Just posted some thoughts for the next few days on my site: chasethestorms.com

 

[Mike Hollingshead]

The 12z WRF has a pretty nice picture for north central NE tomorrow. FWIW

http://www.wxcaster.com/wrfcentralnojava.htm

http://charlie.wxcaster.com/looper/WRF_skewt_loop.php?stationid=_KONL

Skew-t at Oneill at 0z(if you stop it there). WRF has the warm front up there under fantastic shear aloft(50 knot 500mb....100 knot 250mb) and north of the cap. It only has 9c 700mb temps along I80 even. Sure the low level shear is weak, but there is a lot to like on that. Backed low level flow below that veered and increasing with speed aloft flow, pooled moisture at the front, cooler capping...yeah I'd be thrilled if this solution unfolds. Just need any mcs tonight to stay somewhat north. Kind of doubt any mcs tonight is giong to be a killer to tomorrow. Jinx.

It's also firing both north and south NE before 0z.
http://grib2.com/wrf/EAST_WRF5KM_ATMOS_BRF_36HR.png

 

[Craig McPeck]

I am more and more liking the York target for tommorow. Good amount of CAPE, approaching 3000, Good amount of shear, 60-65 dew point. Seems like an idea location.

 

[Ken Johnson]

The 12z WRF has a pretty nice picture for north central NE tomorrow. FWIW

http://www.wxcaster.com/wrfcentralnojava.htm

http://charlie.wxcaster.com/looper/WRF_skewt_loop.php?stationid=_KONL

Skew-t at Oneill at 0z(if you stop it there). WRF has the warm front up there under fantastic shear aloft(50 knot 500mb....100 knot 250mb) and north of the cap. It only has 9c 700mb temps along I80 even. Sure the low level shear is weak, but there is a lot to like on that. Backed low level flow below that veered and increasing with speed aloft flow, pooled moisture at the front, cooler capping...yeah I'd be thrilled if this solution unfolds. Just need any mcs tonight to stay somewhat north. Kind of doubt any mcs tonight is giong to be a killer to tomorrow. Jinx.

It's also firing both north and south NE before 0z.
http://grib2.com/wrf/EAST_WRF5KM_ATMOS_BRF_36HR.png

That shows a huge hook with that supercell across southeast Neb. at 39HR. Man I hope this works out!

 

[Chris Allington]

I think we will be opting for the Southern target as well, somewhere near the Hastings area around 4pm. I like the way low/mid 60s dews are starting to show up across most of C OK streaming N-ward, with some 60s visible in KS as well. Hopefully we wont have mixing issues as most afternoons we have gotten down into the 40s during peak heating.

 

[Bill Schintler]

Chase Target for Saturday, June 06

Chase target:
15 miles east of Lincoln, NE.

Timing and storm mode:
Storms will initiate along a frontal boundary late in the day (6 to 8 PM, CDT), with all forms of severe weather possible early in storm evolution. Later, storms will evolve into a large complex and track east through IA and MO. The severe weather threat will transition into that of heavy rainfall.

Discussion:
A frontal boundary extending NEWD from deepening low pressure over ERN CO should provide the primary focus for another round of severe WX Saturday afternoon, with isolated development further S along the DL in NE to OK. Tonight, the LLJ will aid in the maintenance of an MCS that will track E through NEB, with a resulting OFB roughly along I-80 in ERN NEB by mid-afternoon Saturday. Meanwhile, the synoptic CF will shift SLY S and E, intersecting the OFB near Lincoln by 22Z. Further W, a DL will extend S from the boundary, oriented roughly along US-81 in KS. SC will blanket ECNTRL and NERN NEB during the morning, but will shift NE of the area by the afternoon while allowing for near-maximum insolation (some broken upper-jet CI will persist, but that should not affect heating significantly).

Strong capping will be in place much of the day owing to the presence of the EML, however convection should fire in ERN NEB as stronger UVM approaches after 23Z. Shear and forcing will increase as a piece of energy ejects from the WRN CONUS trough and 90kt H3 flow overspreads the region. Latest indications suggest development of a mesoscale low along the boundary, W of OMA at OOZ; and the NAM, GFS, and most SREF members develop QPF east of this feature after 00Z. Further S, more isolated convection should develop along the DL in KS, building N to S along US-81 from Red Cloud, NEB; to Dodge City, KS by 02Z. Tornado potential should be minimal along the DL in KS due to weaker shear and large dewpoint spreads as temperatures rise into the low-90’s; however, instability and deep-layer shear will support medium- to high-based supercells.

In ERN NEB, deep layer shear AOA 50kts will support storm organization and supercell development. Additionally, LLVL directional shear will increase after 00Z, with SERN NEB lying along the WRN periphery of a 30-40kt LLJ. MLCAPEs will locally increase to 2000J/kg as SFC dewpoints increase to nearly 65F beneath steep mid-level lapse rates approaching 8.5C/km. Storms will grow upscale into a large complex and track E along the IA and MO border, as the LLJ again increases, with heavy rainfall likely given the orientation of the LLJ parallel to the SFC boundary.

- Bill

10:25 PM CDT, 06/05/09

 

[Brian Stertz]

Tomorrow I am quite a bit concerned with forecasted low 850mb moisture, cap issues, and higher LCL's during the daytime hrs. The 00z NAM pops C. Kansas on the dryline/wind shift line by evening. It looks like the better supercell and possible tornado threat will occur after dark here. The Lincoln NE to Fairbury NE area looks to be a solid target on the nose of a pretty healthy theta ridge. Not seeing much QPF on the NAM there, but this would surely be an area of concern. Another pocket of potential supercells and isolated tornadoes will be after dark across NW Oklahoma east of the dryline and dropping LCL's in the 00z-06z period. Time to keep a watchful eye on the RUC tomorrow. It did an admirable job today except for overdosing the CAPEs somewhat. Saturday could be an interesting evening/night chase. Hmmmm.....

 

[Mikey Gribble]

I just copied and pasted from my blog, so here it is and here is the blog if you want to see the other posts. Shameless plug, cough lol. http://loadedgunchasing.com/blog1/

Well that’s a tricky little forecast. The NAM now has 700mb temps down to 10C all along the dryline and is showing scattered precip all along it down into Oklahoma.
I am going to head north towards I70. I would like to get on a storm that fires in the I70 corridor along the dryline for a few reasons. It appears to have the best overlay of instability and SRH just northeast of there. I’ve liked that link kink bulge in the dryline for the last several runs and it’s right along I70 as well.
I gotta swing through Emporia and pick a guy up and then we’ll probably hit I70 and check everything out. Actually we have internet in the car so we should know whats going on. LCL’s were pretty damn high when I looked at forecast soundings this morning, but after just glancing at a map on wxcaster they weren’t that bad if storms can fire early enough to get east into the upper 60 dewpoints. I think I have about a 40% chance at best of seeing a tornado, I just really want to get out there and see a good supercell.
The one huge thing that bothers me and always does is veering 850mb flow. I absolutely hate that. It always screws up the tornado potential. If 850’s were backed tomorrow I would think I was in business. Veering 850’s will chop my confidence level down about 75% so now I think my chances of seeing a tornado are about 15%. I would like to pick up on a storm going up just south of I70 where 850’s back slightly more.
Screw it. I’ll take what I can get. I will see you all out there tomorrow. I’ll be the one wearing a bannana hammock (speedo)and a cowboy hat if you want to say hi. I’m going to try to get a little sun on my thighs in this 90 degree weather. If I start catching any odd looks or people think its in poor form to wear a speedo like that I have a back up pair of plum smugglers from when my dad used to coach softball. That will cover a little more thigh, but not much.

 

[Darrin Rasberry]

Ramming actual surface conditions against the NAM/GFS/RUC progs for 06Z demonstrates two things:

1) The NAM, RUC, and GFS all have, currently, an excellent handle on the system;

2) Neither the GFS nor the NAM progged the current MCS precip mess very well, but the NAM may have the better handle on it due to the extra convecticrap it predicted for Iowa tonight (which will instead simply inherit the Nebraska mess if it survives sufficiently). The RUC seems dead-on, however.

What saith the RUC versus those two? From the 03Z RUC's 12-hour forecast, the corpse of the MCS will still have instability developing in its wake still, agreeing with the GFS scenario (which does not prog as heavy of a remains) - while the NAM's precip forecasting, similar in coverage to the RUC's, eliminates all instability for the affected areas in Iowa. This is of special note due to the further similarities between the RUC and the GFS with progged wind values in these areas throughout 850/500mb, a progression which, especially with the 500's, the NAM disagrees. The GFS and NAM further butt heads at 00Z over the much-maligned shear and turning - the GFS, note, has excellent speeds and some LL backing with height in Iowa (although I don't get what's up with the 700mb's) while the NAM doesn't provide as much backing in the lowest levels.

I am noting also that the RUC slows the system down a bit more than both the NAM and (especially) the GFS as far as its east-west progression of the low.

My targets are: (1) NC Kansas, (2) SC Nebraska; (3) Far W Iowa. with my (1) target as such (barely) because of the better potential sans the precip remnants with respect to (2), and the fact that it could be uncontested as far as flow goes. But (2) is nearby, with (I think) lower LCLs predicted for the area. But the conditional (3) could be my actual play tomorrow if all the ingredients come around, due to the stronger shear and more than sufficient progged instability.

Definitely a day to watch carefully as we're heading out of DMX westbound down I-80.

Prediction for the SPC: 15 percent hail and wind over the obvious region; 30 percent wind for the four corners region into SC to C IA for the inevitable MCS; 5 percent area for tornadoes covering over the three areas above with 2 percent elsewhere, and a possible 10 percent upgrade when the best parameters are known during the day and especially if (3) turns out to verify.

Don't count out the GFS just yet, folks!

 

[Andrew Pritchard]

Looks like southwest Iowa will be as good a place as any this afternoon and evening. Low over southern Nebraska should continue to push eastward to near Omaha by this afternoon. With the aid of the earlier mcs dew points in southern Iowa are in the lower 60s. Surface winds should remain backed ahead of this low, and along the surface front / outflow boundary. Cape will be higher further southwest in eastern Kansas, but LCL's will be a lot better in SW Iowa, and the cap will be a lot weaker. If any storm can go up just ahead of the low and along the ofb I think it stands a chance at producing a tornado.

Current target is Red Oak, Iowa.

 

[Ben McMillan]

The impact of the overnight MCS on today's set-up is becoming more clear. The 12z RUC is favoring a central and southwestern Iowa initiation by 00z.

http://www.weather.cod.edu/forecast/RUC/GL/rucGL_0_cprec_12.gif

This is a bit further east than originally expected, however I'm not complaining as it's a shorter drive for me. Northeast Kansas in still in the mix as well as the possible location for tail-end charlie.

 

[Darrin Rasberry]

Looks like southwest Iowa will be as good a place as any this afternoon and evening. Low over southern Nebraska should continue to push eastward to near Omaha by this afternoon. With the aid of the earlier mcs dew points in southern Iowa are in the lower 60s. Surface winds should remain backed ahead of this low, and along the surface front / outflow boundary. Cape will be higher further southwest in eastern Kansas, but LCL's will be a lot better in SW Iowa, and the cap will be a lot weaker. If any storm can go up just ahead of the low and along the ofb I think it stands a chance at producing a tornado.

Current target is Red Oak, Iowa.

Glad I'm not alone in noticing. The models are making things better for the Iowa area, and it will be amazing for Central IA AND SW IA both where the cells can interact with the respective boundaries once they develop. I'm going to play the northern target since it's progged at least by the RUC to be right over my house (the NAM progs it west of here).

I'm rolling the bones. To blazes with Nebraska; it's make it or break it right here. Target: Des Moines (in case something doesn't happen up here of course). OMW out the door right now!