5/23/06 FCST: KS / NE / SD

[Jeff Snyder]

I'm about to head out with a couple others to somewhere between I-70 and I80 LOL. We're going to head to and north of Salina for now, and re-evaluate when we get there. 6z and 12z NAM runs show a little stronger 500mb flow than did yesterday's 12z and 0z runs, so that part is better. Of course, quality and quantity of moisture is questionable, but there's nothing we can do about that. I am concerned about the 4.5km WRF (with explicity convection) forecasting a squall line across the target area this evening. That WRF run usually does pretty well with storm mode, but I hope it's wrong today. Relatively high LCLs won't help the tornado threat any, but respectable low-level shear and 2000-2500 j/kg CAPE (3000-3500 j/kg CAPE if you believe the 6z NAM) may be enough to yield supercells given 40-45kts westerly 0-6km shear.

 

[Edward Ballou]

Been a lot of talk about NE, and I'm sure that's due to people trying to stay local. I'll be the voice of the north - as Scott is at work (maybe he'll be home over the noon hour). Initial target as Mitchell, SD - I'd probably put the line at about Huron to Mitchell to Yankton. DP's from the 12hr Eta are around 67 in that area. Low level shear looks to be about 20 knots, appearing better than the Neb option. Some higher spots of moisture convergence over Yankton area makes me want to watch that I-90 corridor. Finally the cover from this morning appears to be disappating - should help heating a bit. The boundaries are defintiely visible on satellite. Should be a fun day to sit and watch the storms come in - but I think I'd rather go meet them - 3 weeks to the day since my last chase.

 

[Mike Hollingshead]

Well I don't really have a bias towards one target or the other beings as they are pretty much the same distance. I think both will have similar shear since up north the upper backs some but so does the sfc. In sc NE the upper is more veered as is the sfc. I'm starting to wish I was closer to one area! It is extremely rare I pick a southern area down the dryline some. It is also very hard for me to not race after early convection and wait in an area for later stuff. So if I choose the south one I am wondering just how hard it will be for me to wait. It is also hard to tell just how far south things will go.

The ruc has a long area of strong convergence in c KS along the cf by 0z. Here Change the 12 to a 9 if viewed closer to noon or later. Last night's wrf precip forecast that has been used alot lately showed that whole thing quickly becoming a linear mess. So I wonder if perhaps there might be less convergence and linear forcing in the north target. Ruc is also initiating something in se NE in another area of convergence. That area bugs me as I could see something popping there. The other thing that could happen is most of KS being shut down till very late and having one isolated storm do very well with the westerly flow aloft and the very strong southerly inflow. I think like most setups there will be two decent areas. Which one is more prefered is what I can't figure out yet. I guess since I never opt for the southern, later option maybe I should give that try. The northern area it seems the sfc boundary will be under stronger upper flow as well. Uggg. If the winds don't really back at the sfc up there then I don't think I'd want to be there. I guess I wonder what the likelyhood of a more isolated nature up there is.

I'll probably pick the south option very near the KS border and hope that area stays the furthest south for a while. I imagine it should. I really like that area if it can stay isolated for awhile. It would be hard to ignore the 25-30 knots of southerly sfc flow(maybe even a bit more backed if that low being hinted at can be stronger) with a wsw 40+ knot mid-level jet over it. Target has been Red Cloud NE for a while now, I guess I'll just stick with it.

 

[Fritz Kruse]

I am liking eastern SD and far northeast NE for the best chance of tornadic
supercells. However I am still in Dodge and just may go after "Tail End
Charley" in northcentral KS.

The LLJ should be cranking by sunset and may help out in increasing
convergence for any supercells. First pick now is Osborne to Smith Center
area around 7 to 9 pm.

500 to 900mb crossover flow looks adequate for rotating supercells and
if the dewpoints can stay in the mid 60s a few tornados look possible,
although the Temp-Dewpoint spread kind of high. I think the LCL's
will be lower as you go north, and that is why I think the better
chance of tornados is up in South Dakota.

 

[Kurt Silvey]

I too prefer the setup in se SD over the southern target, but I think to get isolation, you will need to be there early, 18 – 21z, as things should line out as they move east.

Sioux Falls - Forecast Discussion

Unfortunately I cannot get out of Omaha until ~ 21z, so my choice is made for me. I will head west and south as quick as possible and hope for a late blooming tail end Charlie along the KS / NE border, maybe somewhere south of York.

 

[PeteMcConnell]

Mesoscale discussion now in effect for eastern SD and NE. Hopefully a tornado watch issued by 2 p.m. Dan Robinson's crew, Kurt Hulst, Pete McConnell and Nick Grillo are waiting and watching in Hastings for things to progress. Hopefully isolated supercells before a line forms. Good luck to SD chasers and the southern groups.

 

[Scott Olson]

Been a lot of talk about NE, and I'm sure that's due to people trying to stay local. I'll be the voice of the north - as Scott is at work (maybe he'll be home over the noon hour). Initial target as Mitchell, SD - I'd probably put the line at about Huron to Mitchell to Yankton. DP's from the 12hr Eta are around 67 in that area. Low level shear looks to be about 20 knots, appearing better than the Neb option. Some higher spots of moisture convergence over Yankton area makes me want to watch that I-90 corridor. Finally the cover from this morning appears to be disappating - should help heating a bit. The boundaries are defintiely visible on satellite. Should be a fun day to sit and watch the storms come in - but I think I'd rather go meet them - 3 weeks to the day since my last chase.
[/b]

LOL. Im already in Mitchell, im planning on heading SW of here to my target in the next hour. The RUC forecasts good helicity just S/SW of here at 21z and then the rest of Eastern SD at 0z which should be quite nice given the western edge of a 40kt LLJ and backed surface low.

 

[Kyle Masters]

I'm looking at the Mitchell/Chaimberlain area in SD to start with, and work my way back east following the storms. Judging by some of the dymanics, everyone I know calls me crazy, but I just have one of those "outbreak" type gut feelings. I hate those...

Anyways, with 60's dewpoints, the LLJ flaring up, and the cap starting to weaken, starting to look interesting so it's about time to close up shop and head west.

If no tubes are out, at least I'll probably get to see some good structure and some large hail. My plan is to beat the storm back to where I live so that I can get ahead of it and get some pictures of the leading edge of he system.

Good luck everyone out today!

 

[Ryan McGinnis]

I'm sittin' in Lincoln right now trying to decide whether to take a day off of work or not. South Dakota is outta the question for me right now, and I'm not sure if it's worth driving that far west. I do notice on the surface obs that there looks like there's a bit of a dry punch coming up from Kansas into SC/SE NE. Tds here in LNK are 64, and as you look W and SW on the surface chart, you see a line of Tds in the 55 range.

 

[nickgrillo]

I'm currently in Hastings relaxing with everybody at Pete McConnell's place (right off Hwy 231 S) and waiting on initiation (in a prime area right now I'd think). Latest RUC mesoanalysis shows widespread 1500-2000 j/kg sbCAPE across the area, with strong low-level turning with height yielding 100-150 0-1km SRH. Strong insolation and associated low-level convective mixing has slowly decreased Tds a bit across southern NE and northern KS -- which, per latest RUC mesoanalysis has decreased CAPE ever-so-slightly around this region -- and is also maintaining the high LCLs (i.e. 1600m AGL). Nevertheless, southerly 850mb flow below strong 30-40kts southwesterly flow aloft at 500mb still poises a favorable deep-layer shear profile for supercells, with 40-45kts of 0-6km shear progged in the region by later this evening.

Convective initiation should occur further to the north in a few hours, and slowly build southward. As Mike H pointed out, there is significant convergence progged along the sfc trof/dryine in central KS later this evening, which could provide strong enough forcing for ascent of low-level parcels. I'd think SPC would go with a big red box from eastern SD and then southward to the KS border...

I'm still sticking with the "southern" target.

 

[Kyle Masters]

Sort of off-topic, but what happened to that map that used to be on the stormtrack page where everyone could add their targets and it'd show where everyone's going?

These storms that are firing along the MO river in SD and south of there can't be the ones that are supposed to get nasty, are they?

 

[Kiel Ortega]

I feel lucky I don't have to make any tough choices today as I am in Norman working on Project SHAVE (http://ewp.nssl.noaa.gov/projects/shave). Kinda wondering about the southern NE (which is C NE I guess) target as it looks as if the southern-most vort lobe just over the N CO Rockies is doing as the models said it would and join the other two to the north to make a fairly large vort lobe over W SD. Seems it's going to jet out over W NE; this is per water vapor and vis sat and the cu field in W/C NE towards SC SD. Best wind profiles at the time are towards northeast NE/SE SD, with absolutely horrible profiles from the 18Z ABR sounding. With current RUC analyzed 0-6 km shear near the dryline(?) in C NE getting very parallel to the surface bndry. If cells can't get going early, looks like a linear mess; however, if the southern vort lobe really does just take off, there might be some areas in C NE with some very favorable shear profiles for a supercell (which hopefully won't be embedded in a mess). Best of luck to all who are out.

***EDIT*** Go figure as I typed and help set up machines, some stuff initiated in N NE...let's see how they do :-/

 

[Bart_Comstock]

FYI: There is now a red box over most of Central and E SD, and much of C Neb and NE Neb. Some cells are starting to pop up in NC Neb, however there are not yet any warnings with these cell.

I am currently in York, NE, and although it is tempting to move North I agree with Nick, and I am going to currently stick to the "southern" chase area.

 

[Chris Allington]

Already looking like the storms currently forming are not isolated enough... everything kinda went up at once and appears to be struggling. Also surface moisture seems to be mixing out pretty quickly now with many stations going down a few degrees in the past hour...

 

[Kyle Masters]

I'm thinking that these storms that are there now may be to far south to tie into the energy that's available up north, over the MO river in C SD. I'm feeling that these storms will be more linear in nature, and to the N, E and S of this system there will be more isolated and stronger storms. The dynamics just look better to the N, E and S of the present precip areas.

I just think that the system needs to move farther east before the real show starts.

EDIT: although, the cell is far away from the FSD radar, the cell east of Chaimberlain, SD (just crossing I-90) is starting to pick up a nice velocity profile on the last few scans