5/24/08 FCST: SD/NE/IA/KS/OK

[Mike Peregrine]

Can't let the weekend days slip by us, so I'll go ahead and start one up for Saturday now as well. Looking at GFS primarily at this point, a now rising 1000mb low sits in the same spot in northeast Colorado as the previous two days. Surface winds are a bit worrisome on Saturday, as they are currently forecast on the weaker side at 10-15 kts, again out of the southeast. Dewpoint remains high across central Kansas, with Hays-Salina area looking best. 700mb winds turn to southwest @ 25 kts., 500mb are SW @ 40 kts, 250mb winds are SW @ 25-30 kts.

Not quite as dynamic as the previous two days, and perhaps a bit further east, but with shear and instability still present, Saturday looks like the possibility exists for storms

 

[Mike Peregrine]

Models remain in agreement for Saturday. Forecast low will be 996mb still on Saturday, per NAM with placement over NE Colorado. 1000mb per GFS, over western Kansas. Eastern high appears to be breaking up and starting to move out of the picture. TDs in the 70-75 degree range in eastern Kansas/western Missouri. The dryline will stay in the same areas as previous days, across western Kansas. While the juicier air looks to be well east of the dryline, instability continues to look good from Hays almost to Colby. The winds across eastern Kansas look to be backed, while those in western Kansas are more out of the south. Surface winds still appear generally weak to me. I'm still thinking of a possible chase target evolving over the next couple of days along I-70 that could end up anywhere from Salina to Wakeeney (again). Just get a hotel and set up camp in Kansas this weekend.

 

[Jason Branz]

Agreed Mike. Things I like about Saturday:

850 & 700 mb winds...nice speed maxes move across NW KS by 00Z Sun. A small CAPE/Theta E max is progged around Colby/WaKeeny and northward. There also looks to be decent convergence on the dryline.

What I don't like...well, not much really. And it's Memorial Day weekend, which usually doesn't disappoint.

Target: Hill City KS.

 

[Brandon Sullivan]

Hmm.. Currently heading east from a busy day in central KS...

Pondering over the placement of the SPC forecasts and the GFS/NAM.. GFS seems to be further west with the DL..

Will probably target North Northeast KS, and or adjacent areas of Nebraska..

CAPE/Helicity seem sufficient for a good day..

I like the setup.. Hope for some more tubes..

 

[Bill Schintler]

Chase Target for Saturday, May 24

Chase target:
Mahaska, KS (near the KS/NE border).

Timing and storm mode:
Storm initiation will be 5 PM CDT, with a few supercell storms early in convective evolution. Storm mode will transition to multicell during the evening.

Synopsis:
Omega block will break down over the next 48 hours as closed WRN CONUS low opens up and flow becomes increasingly zonal. Meanwhile, New England trough will lift NE into the Canadian Maritimes by day 3 as low-amplitude ridging becomes established over the SERN US. In the low levels, lee cyclone near Denver will lift N while pulling a WF into the upper Midwest. The SRN end of the WF will remain largely quasi-stationary in nature, and will extend alone a Valentine to Grand Island to Emporia line by 22Z. The DL will mix E during the afternoon, intersecting the WF near Kearney during the same period while serving as a focus for convective initiation.

Discussion:
LLJ axis initially from the CNTRL plains into the NRN high plains will gradually veer E into the upper Midwest and then finally into the WRN Great Lakes in response to the NEWRD transition of the aforementioned S/WV trough. This will result in the NWRD transport of a very moist BL AMS into the CNTRL plains near the retreating WF. Strong instability will result as a plume of steep mid-level lapse rates overspreads the area, with an axis of 2500J/kg MLCAPEs nosing into SRN NEB. Latest MDL trends have underestimated the degree of AMS recovery following tonight’s storms. Elevated storms will be ongoing during the morning along the LLJ axis, primarily in NEB and N of I-80, and storms will move N and E of the area by noon. Thick ST along and E of US-81 early in the day will also exit the area to the E, while allowing for strong SFC heating with SRLY LLVL flow. Convective initiation is delayed until 22Z as a 10-11C H7 thermal ridge shifts E and the divergent RRQ of a 120kt H25 streak overspreads the area. Shear parameters will not be as impressive as was the case the last two days where extreme directional shear existed in the SFC-1km layer coincident with LCLs in the 600-800m AGL range. Nevertheless, 200m2/s2 of SRH and 60kts of bulk shear will be sufficient for storm organization and rotating updrafts.

- Bill
11:30 CDT 05/23/08

 

[Kevin Crawmer]

I really think today has potential. The two negatives are a lower 0 to 1 km shear than yesterday like bill said and the questions on the dry line mixing. The good is it looks like there should be a narrow area of adequate instability and shear in extreme eastern Nebraska. Current target is Lincoln by 1 PM and adjust from there.

 

[Jason Branz]

Sitting in Lexington this morning, and based on morning obs, I think I'll just drift over to York and sit there for a while. Upon first glance, I really liked the O'Neill area due to good convergence, but I'm not too confident about airmass/moisture recovery that far north. Looks like a classic case of thermo south, dynamics north. Hmmm...

 

[Chris Hayes]

Main concern thismorning is the moisture return into eastern and central Nebraska. 60s dewpoints dont start till southern Kansas, and you have 40s to low 50s dewpoints across Nebraska. I like the fact that there's an outflow boundary from about Salina NNE into Nebraska that might enhance supercell formation. So, what I think I'm going to do today is head toward he state line and adjust from there. Might head further into Nebraska if moisture return is more than sufficient. I think the southern target is more favored today. Target: Hebron to Beatrice.

 

[Mike Peregrine]

Doesn't look like the storms will slow down for us much today, but at least they'll be moving in a more familiar direction! RUC indicates best moisture return and Theta-E ridge across extreme SE Nebraska. I also like the wind down there, and feel there is a good shot at a supercell later on, provided instability can come up. My preliminary target is Beatrice, which can be revised after lunch. I really hope something does pop up around there, because its familiar ground.

 

[Mike Hollingshead]

Hmm, maybe this morning's strange occurrence is a sign of a better day for me(or not, since I thought my gps working on gr for the first time yesterday would be that day's good sing). Woke up groggy as hell and noticed a rainbow colored circle next to the door. Looked almost like someone spilt oil there, but it was a little too luminated. I was just like, I know I'm really tired and all but what the hell! The blinds were closed, and it was right next to them. I'm like, eh! Then I look clear across the room and see another on the mirror, lol. Sun was shining straight through the peephole in the door creating two circle rainbows, one on the mirror and one back next to the door. That was slightly fun to photograph as it did this for the next 15 minutes or so. Just wished I'd thought of a few ways to do it sooner. It was "light" on what would become a good day(?). Then I turned the pc on and looked at reality!

Bah at that massive mcs ongoing. At least it is early I guess, but man I hate chasing a small pinched moist axis. I also hate guessing on return, but am slowly more encouraged upper 60 dews can reach se NE. I'm far less thrilled with today's setup obviously, but it seems I see better things on lesser days than I do on better days(even though the better days are producing, lol). Anyway, today seems all about getting the instability up here where there's a little better sfc convergence, then hoping for some good deviation to increase the sr low level shear. Biggest concern, the juice getting here. I'd say Hebron is as good as target as any. Now how to take a few hours to get there from here in McCook.

Go dews go.

 

[Jonathan Whitehead]

Well another day in the office for me, but im getting used to it.

Currently trailing line of showers and thunderstorms are developing from the MCS in east KS SWWRD to just west of ICT . Not really sure what initiated it, but obviously shows that airmass over the region is nearly uncapped. Would love to have a 12Z sounding for ICT. Bout half hour ago walking into work downtown I did see a few breaks in the low overcast cloud deck and saw tall hard towers above it thru the breaks. Nothing big but it showed what atmosphere is like not too far above surface. If we can get a cap in place and some insolation, I think this area would be primmed to see some interesting activity in the afternoon. But unlike the past 2 days, theres a lot more "ifs" with today.

 

[Brett Adair]

Shear may not be the best, but given instability fields I would play the ICT - SE KS area into N OK. I look for enough insolation to occur to yield a few "beasts" in this area later today. SRH isn't terrible with the boundary around (0-1km AOA 300 m2/s2). May not be a bigg chaser convergence down there either.

 

[Tim Marshall]

TARGET: Pratt to Great Bend, KS TIME OF DEPARTURE FROM SALINA: 1 PM. Looks like tornadofest -day 3. Overnight convection has stabilized the air mass in eastern KS and NE, but the MCS is out of here and strato-cu is strobing the sun here in Salina. I expect the "juice" in central OK will return to KS throughout today. I like the WRF sharpening the dryline in southern KS and I don't like the narrow CAPE tongue in SE NE. I also don't like the subsidence of the departing storm system from yesterday north of here. In contrast, the RUC shows no such sharpening of the dryline, 70 dewpoints roaring back into SE NE and precip breaking out there. Hmm. Should I go north or southwest? Given this dilemma, I'll stay put awhile here in Salina, have a leisure lunch myself, recheck the data, then probably head southwest. For the rest of the memorial day weekend, it looks like chase days each day through Monday, before a ridge builds temporarily over the central plains. TM

 

[Brandon Sullivan]

Left Salina, KS early this morn. About 10 minutes out from York, NE. Which will be our target. Dewpoints beginning to advect northward toward the area behind the ongoing MCS to the ESE.

Sun is shining brightly here, and winds are out of the south, at about 10 MPH.

Going to stop in York to analyze, with a seemingly good road network,

Good luck all. Looks like better daytime tube potential, compared to our other tubes at night...

 

[Brian Stertz]

Latest RUC looks good...

Like the looks of the latest RUC east of a O'Neill to Columbus to Fairbury NE line. Things looks especially good across EC/SE Nebraska into extreme WC/SW Iowa where strongest instability/shear is located...and the width of the theta ridge is widest. The chances of the show being over quickly are higher as you go north into NE Nebraska and W. Iowa...where there is a narrowed instability poke. Presently in York NE and planning on maybe fudging a little east towards Lincoln-Omaha area this afternoon. I like today if the RUC pans out....