5/29/07 FCST: TX/CO/OK/KS

[Dustin Wilcox]

The last couple of runs this setup has really begun to look good for supercells in portions of the Panhandles and SE CO. I like the Guymon OK area where one can go any direction quickly, and with a decently curved looping hodograph, over 3000j/kg CAPE and a 3km EHI of 8.4 and 1KM of 5.5 one may not have to travel far. Nice backing of surface winds will occur near the surface low, and per the 12KM 12Z ETA nice backing of a 40kt LLJ will be present over the region. The same run also has a piece of energy bringing 40-45kt Westerly and maybe even WSW 500mb flow over the region by 0Z. Helicity values as usual really increase shortly after 0Z IMO tomorrow looks really good per the latest model run.

 

[Andrea Griffa]

The last couple of runs this setup has really begun to look good for supercells in portions of the Panhandles and SE CO. I like the Guymon OK area where one can go any direction quickly, and with a decently curved looping hodograph, over 3000j/kg CAPE and a 3km EHI of 8.4 and 1KM of 5.5 one may not have to travel far. Nice backing of surface winds will occur near the surface low, and per the 12KM 12Z ETA nice backing of a 40kt LLJ will be present over the region. The same run also has a piece of energy bringing 40-45kt Westerly and maybe even WSW 500mb flow over the region by 0Z. Helicity values as usual really increase shortly after 0Z IMO tomorrow looks really good per the latest model run.

Moreover we have to say that by 12Z the mid level flow is improving, with value of 40-45 that could be sufficient to tilt some nice updraft and we could have a chance for some isolated tornadic supercell, if the models confirm, as we have a very large amount of low level shear and amazing hodographs plus dews in the low 60.Too bad for the lack of high level flow that could lead to the formation of HP supercells, not too simple to chase.
So far I like so much the triple point w of Elkhart and the dry line in the Guymon/Texhoma zone.

 

[Bill Schintler]

Chase target for Tuesday, May 29

Storm chasing target for Tuesday, May 29:
Selkirk, KS (40 miles NW of Garden City).

Timing:
Storms will initiate in eastern CO along and N of US-40 by 4 PM CDT, and then develop southeastward towards the deeper moisture and optimal shear in the target area by 6 PM.

Storm mode:
Supercell storms during the first hour or two of storm evolution, with a full spectrum of severe weather including a short-lived tornado or two. Overnight, storms will evolve into a large MCS and track southeast towards Garden City, KS, making for a good nighttime lightning show for chasers who elect to stay there for the night.

Synopsis:
Evening analysis indicated deepening H5 trough over the NWRN CONUS with strongest height falls noted over CO. Soundings in NM and CO all indicated steep lapse rates from the SFC through 600mb, and differential advection of this airmass from the SW and deep moisture with SFC dewpoints AOA 60F from the SSE during the period will result in an EML.

Discussion:
Strong synoptic-scale assent will exist at the exit region of a 55kt H5 speed max rounding base of closing ULVL trough. During the day, SFC low-pressure will strengthen and drift slowly to the S towards Dalhart, TX in response to both ULVL dynamics and strong differential SFC heating. A WF will extend to the NE of the SFC low and a DL will mix EWRD into extreme the WRN TX panhandle and KS. Insolation will be limited N of US-40 in WRN KS and ERN CO as a mid-level cloud deck develops during the afternoon in response to isentropic up-glide along the 320-330K SFCs N of the WF. Regarding model performance, previous runs of the GFS had trended more to the N with SFC and ULVL features then the NAM, however the latest NAM has come into close agreement to the GFS.

Capping will be in place throughout much of the afternoon however SFC forcing near the triple point of the WF and an advancing DL should be sufficient for convective initiation. Once storms develop, a brief window of time will exist as they move NE of the triple point into an environment with impressive hodograph curvatures (SFC-1km and SFC-3km) along with SFC dewpoint spreads of 10F contributing towards LCL’s AOB 1000m AGL which may be favorable for brief tornadoes until supercells move too far NE into the stable cool-sector airmass. Modals also advertise a compact 30kt H7 speed max that will approach SWRN KS after 00Z, and this feature should enhance shear and hodograph curvatures. A 45kt LLJ nosing into SWRN KS will assist in the maintenance of a strong MCS during the overnight hours.

[FONT=&quot]- bill[/FONT]

 

[Shane Adams]

5/29/07 NOW: CO/KS/OK/TX

Chad Lawson and I are heading northwest to Liberal, KS. Will adjust from there, but we're liking our chances for a few tornadoes today. Just enough cap to keep things isolated for a few hours at least, plus great backing winds along with a (semi) h85 "jet" working its way into the SW Kansas area by 0Z. Windfields in the h7-25 range are somewhat weak, but the directional shear is good. Helicity values should be quite favorable for spinning storms, and with cooler temps just east of the low, the dewpoint depressions should set up well for tornado chances, as long as storms can remain discrete. Feels like a "sleeper" kinda day that could produce quite the trophy....we plan to be there when it happens.

 

[Richard Halter]

Seems easier and nicely clustered today

Chuck Vlcek, Steve Flood and I have a long way to go ;0 - McCook to Dodge City to probably Garden City and watch for the development. Love the latest SPC progs, may not need to do a lot of driving over the next three days - after all the miles north and south, I hope the SPC and the conditions merge into a caprock picnic!

 

[Angie Norris]

Heading out the door...starting point Panhandle TX...can easily adjust north, east or west from there. Tolerable shear, dewpoints good with deep moisture, very nice CAPE (~3500J/kg)...when the cap breaks, we should see some good storms.
Good luck, safe travels and happy hunting to all!!

 

[Jeff Snyder]

We're about ready to leave for the northern TX panhandle / OK panhandle / maybe extreme se CO area... Main concern is meager mid-upper level flow. But, as others have noted, directional shear should be quite good by evening as backed surface flow underlays westerly midlevel flow. With moderate to strong instability and good veering wind profile, supercells seem like a good possibility. The 12z AMA sounding isn't particularly nice, except for the favorable lapse rates. That said, deeper moisture should reside just east of there (see DDC sounding), so I expect deeper moisture to be pulled westward into the central panhandles later this afternoon. It isn't the best setup by any stretch of the imagination, but we only have a limited time left with the mobile phased array, so we're taking a shot at it.

 

[Stuart Robinson]

TARGET: TRIBUNE, KS - Long haul from Jamestown, ND. Drove down to Valentine, NE late last night and caught a few hours sleep. Thank god for Starbucks in North Platte, NE. I like the backed surface winds in western KS northeast of the surface low. Nice 30 kt westerly jet at 500mb progged by RUC and ETA to exit over eastern CO by 00z. It's good to be back in the ole stomping grounds. Agree with others on several days of chasing ahead. What a turn around in the models from just a few days ago. TM

 

[Andrew Stoller]

I agree with Stuart; Tribune would be an ideal starting spot; heck, maybe even a hint more northwest from there like Burlington. With the position of the surface low, southeast CO is Capeless and dewpointless but a tongue of solid 50+ to near 60 dewpoints seems to advect west right along I-70 into northeast CO/northwest KS/southwest NB. The RUC hardly breaks anything out around southwest KS; everything is more to the north around Goodland.

 

[Mark Blue]

I also tend to agree with Andrew about the RUC and how things fire around 21Z today. My wife (Jane) and I want to work our way towards AMA (the next two days especially), but for today we are heading for Goodland and maybe as far south as Tribune KS. We're in NE Colorado right now (Wray area) and the moisture in the air is thick. In fact, it's raining lightly as I type this. It's taken me three hours to pick a target point, and I'm finally commiting to west central KS.