6/9/09 FCST: KS/OK/MO

[Michael O'Keeffe]

Surprised no thread has been started about this! The latest 12z NAM looks pretty good for tornadic supercells in SC/SE KS tomorrow. Directional shear is great creating some massive hodographs from Wichita to Emporia east to Chanute. CAPE will be OK with 2000-3000J of CAPE over the region and helicity will be great with 0-3km values approaching 500 m2/s2 and 0-1km values 250+ m2/s2. The low level shear looks great with a nice SE LLJ with winds between 30-40knts. The cap also looks breakable along the warm front which is another plus. I don't see many flaws with this one so we should really be watching it!

Check out this sounding at 0z Tues. for Wichita
http://beta.wxcaster.com/cgi-bin/parse_skewt_trace_all.cgi?model=NAM&STATIONID=ICT

 

[Andrew Butler]

Weak surface inflow doomed what most of us thought was going to be a good tornado day yesterday, and just quickly glancing at things I can see potential for some problems there. I'm just trying hard to find a fly in the ointment of an otherwise great looking set up.

Best looking hodos I've seen all year...

 

[Chris Allington]

Really like the forecasted shear profiles and hodos on the NAM, but the GFS has the better instability. Either way we will be trying to find the warmfront wherever it sets up with some surface heating. Potential convection should be going on most of the day elevated on the north side of the front, but this might help reinforce the boundary. SEly surface winds with WSW 40-50kt winds in the mid-levels look great as well. Even if there arent many tornados someone should be able to find some incredible structure somewhere. We will be out and are currently targeting somewhere just E of the Whichita area.

 

[Mikey Gribble]

I just noticed tomorrow's setup literally 30 minutes ago. I've only browsed the models briefly, but that is a seriously good combination of paramaters coming together. From what I've seen that should easily make moderate risk 15% tornado probability along the warm front. I may be missing something since I just glanced at it, but it looks to me like tomorrow is a solid tornado setup.
As soon as I finish forecasting I'll post then.

 

[Tim Supinie]

I've been watching this setup for a couple days now, and I can say that I really like the NAM's forecast sounding for 21Z 9 June in the Wichita area. Instability could be better for June, but ~3300 J/kg SBCAPE is more than good enough, especially given the shear. Storm motions are pretty good (30 kts), LCLs are reasonable (1000 m). Now, to complete the picture, it needs to completely fall apart on tomorrow morning's 12Z runs ...

Strongly considering chasing tomorrow, but I've got work concerns. NAM has morning activity moving through (hopefully laying down some nice outflow boundaries) and the main show developing in the Wichita area between 21Z and 00Z, so if I were to chase, I'd plan to be in Wichita by 3 or 4 PM.

 

[Chris Wilburn]

I have been watching this setup for a couple days now. Of course it is more uncertain a few days out than a classic dryline setup due to the stationary/warm front placement. With that said both models generally agree on a placement of the front roughly in SC/SE KS into central KS. Also appears to be a dryline punching in from NW OK to just SW of Wichita as well.

The fine details of front placement will obviously be key tomorrow. However, everything else in place for the potential for tornadic supercells. I think staying just east of I-35 will be key as the 850mb winds are forecasted to be pretty anemic just west of I-35. Anyway, the forecasted sounding in a post above for Wichita looks very nice valid 00z. Speed and directional shear are very very nice, which is yielding very nice 0-1 and 0-3 SRH values sufficient for tornadoes. CAPE should be near 3,000 J/kg and td's will obviously not be a problem running generally upper 60's to maybe even very low 70's. There should be some elevated morning convection near and just north of the front that could cause some issues, but I am not too concerned. This could also put down a nice OFB for later in the day when surface based storms will begin to fire. A strong CAP is forecasted at 18z, but quickly erodes sometime between then and 21z allowing surface based convection according to the models. I really don't see too many limiting factors with this setup. At least not enough that could drastically change things. Current thinking is heading to near Ponca City with probable adjustment north into KS and finding where the front is located.

The front currently appears that it has stalled along and just north of I-44 in Oklahoma. It will be interesting to see how far north it meanders this evening and tonight if any.

 

[Eric Bucsela]

Tonight's 00z NAM has backed the surface low, dryline, etc southwestward a bit. Also improved the H5 winds and CAPE in southern KS. Although best 850 winds still are further east, I'd target the area between Dodge and Pratt (maybe south of that depending on how far north the front makes it) at least for initiation. Just a guess right now. We're overnighting in Great Bend and expect more target tweeks after we look at the morning data.

 

[Ken Johnson]

This set up looks good, but I don't like the early convection the 00z NAM paints.

 

[Greg McLaughlin]

This set up looks good, but I don't like the early convection the 00z NAM paints.

If you examine the NAM carefully you can see it weakens the mcs across Kansas between 1pm and 7pm and develops new storms along the outflow from the morning convection in Kansas.

 

[Bill Schintler]

Storm Chasing Target for Tuesday, June 9

Chase target:
Ten miles west of Pratt, KS.

Timing and storm mode:
Elevated convection will be ongoing during the morning in KS, especially in areas N of US-50. This will push east of the area by late afternoon, and then, surface-based convection will fire after 6 PM CDT. A few supercells with an attendant tornado risk will be possible, before storms transition into a multicell complex by mid-evening.

Discussion:
The SWRN CONUS trough will slowly amplify as a 120kt H3 speed max ejects towards the central Plains. At the SFC, low pressure will deepen over extreme SERN CO, with a WF extending E across SRN KS near US-50, which should serve as the primary focus for convection Tuesday. Additional storms may fire further S along a DL extending from the WF from near Pratt, KS through Childress, TX; however, insolation in OK and TX will be limited due to a CI shield. This may be favorable; however, as storms along the DL may more likely remain discrete while initiating only within pockets of clearing of the high clouds. Morning convection, resulting from WAA along the nose of the LLJ N of the WF, will result in differential heating across SRN KS. These storms will push E of the area by afternoon, while leaving behind an OFB that should reinforce the synoptic boundary.

Looking at the latest model runs, the GFS continues its trend of favoring a more northerly track of the SFC features through KS then the NAM. A mix of the two solutions is prudent, while favoring a southward track indicated by the NAM due to the influence of the OFB from earlier convection. Capping will remain strong throughout the day; however, up sloping flow and increasing convergence along the WF should weaken the cap – especially near the WF/DL triple point. Ample instability should exist within the warm sector, with MLCAPE’s locally increasing to 2000J/kg with mid-60’s dewpoints beneath steep mid-level lapse rates of 7.5-8.0 C/km. Deep-layer shear of 50-60kts will be supportive of storm organization. Additionally, LLVL directional shear will dramatically increase during the evening hours as a veering 50kt H85 LLJ overspreads backed SFC flow along and N of the WF.

- Bill
10:56 PM CDT, 06/08/09

 

[Mikey Gribble]

I am worried about convective evolution more than anything, but along that front conditions are excellent for tornadic supercells. Look at the Enid hodograph and that's not even in the best spot, it's just the first hodograph I grabbed that was close to my target area.

LCL heights behing a little high and convective evolution are the two big unkown and potential spoilers for tomorrow.

If storms can fire in clean clear air and mature before moving across the front and into weaker instability, they could be very good. If a supercell rode that front there is no doubt it my mind it would pose a risk of strong tornadoes.

My target entirely depends on where the front sets up. I really like the setup for tomorrow. As far as strong tornado potential goes, I think this is the best strong tornado environment I've seen this year. EHI is at 10 on both 1 and 3km. 1km SR winds are 40kts and 1km SRH AOA 300kts all with strong deep layer shear and CAPE over 3000j/kg. That is pretty nasty stuff.

Like I said before and I can't say enough, frontal location will be the key to targetting tomorrow. The key to getting strong tornadoes is convective evolution. If convective evolution unfolds well then a tornado cluster is likely IMO.
Here is a link to my forecast on my blog and a map I made http://loadedgunchasing.com/blog1/

 

[Derek Weston]

Could be a big day. We have the *chance* to see great low level shear coupled with very good CAPE -- something we've not been able to manage often if at all this chase season. (at least in territories we want to chase)

Though the cap doesn't seem too big an issue (outside of S central KS) the 4km WRF-NMM precip model doesn't want to break out a supercell until the 02-03z timeframe in central KS. (not that we are to live and die by this model... but I think it's got something to say)

Other concern is the placement of the strongest 850s being placed more towards E KS away from the best CAPE which is back more towards central KS.

Of course the best is SRH also a bit east and north of the ideal CAPE according to the NAM.

So for our sake, hopefully that's a bit off and our ingredients are juxtaposed atop each other in the same region. (again something we've had trouble attaining this season -- this Sunday being another nice example)

 

[jshields]

the SPC has upgrade their risk to moderate for central kansas, with now a 15% tornado risk area and potential for stong, long track tornadoes the shear profiles are very impressive with most areas in central kansas having a 0-1km srh over 300! the nam keeps the cape way further south and west in kansas, but the gfs has it further east in central and eastern kansas up to about I-70. looking at some of the hodos, around manhattan and salina it shows only about 1300 j/kg CAPE, but lcl heights are below 500 meters. so even with the lower cape there should be a good chance of tornadoes. we'll see whether any morning convection and cloud cover messes things up near the warm front where the shear is the greatest. i have to sit this one out i went out sunday and basically used up my trip for the week and my day off from work, so my wife wants me to stay home. it's something i'll have to watch from my computer at work so i'm sure there will be a ton of 'naders good luck all! if it's anything like sunday there are going to be a ton of people out on the roads!

 

[Jason Persoff]

Actually, I just don't think this am's convection is going to screw anything up. The MCS is impressive in N KS right now, but there are indications of an OFB moving south from this convection which, if timed right, will coincide with areas where the warm front will be later today. Between the front, the nose of a small but intense upper level disturbance, and the OFBs from the MCS, there will be an explosive target in the area just around ICT by early evening. The setup is better than a few days ago.

The fact that the threat is a conditional one, one that needs the cap to break, only adds to the intensity of the threat from mesoscale phenomena such as the OFB causing only discrete initial storm modes.

I have to say, the lackluster chasecation I had is killing me with severe SDS. Today's setup is the best I've seen this year and storm motion won't even be that fast and will be over chaseable terrain with reasonable roads. I just...I mean I just can't emphasize enough how envious I am for those out there. For those who live in ICT, though, the day is going to be a long one with the potential for serious badness.

EDIT: I have to laugh. So I've got a full hospital of patients to see, have no $$$s to go chasing now, and yet...after reviewing the setup, I actually logged into travelocity to look for flights. That they are running almost $1000 for me to fly in today and out tonight of ICT is probably the best thing (I can't afford that or convince my wife that this is a worthy expense). So now I know I've done all I could. I can't be there today no matter what. Just had to commiserate.

 

[Jacob Ferden]

Chase target: Wichita

I will be arriving in ICT around 3 PM. I will adjust from there based on the position of the warm front and any notable OFBs. I expect initial surface-based convection to fire along or just east of I-35 between 4 and 6 PM, with the greatest threat for strong tornadoes sometime after 6 PM as LCL's lower. Looks to me like a batten down the hatches sort of day for Wichita, Ark City, Winfield, etc. Good luck to all who chase today!