06/01/09 FCST: CO/KS/OK/TX/NE/IA/MO/IL

[jamesmseitz]

This system is not perfect at all but because of it's location in the High Plains I believe it will yield a few descent storms.

The System with enter the Plains at or Near the Co KS boarder and with some instibility and moisture in place. Plus as stated before, the high plain with the front range will produce some up slope in the area. I know the winds aloft will be less than perfect but still is worth watching for now.

 

[Andrew Stoller]

The GFS has been quite consistent now with Mondays potential. Two areas interest me, with the first being northeast CO/western KS. The GFS has consistently showed a short wave coming through the mostly zonal upper flow, with a nice easterly upslope post frontal surface flow. The second area of interest is eastern KS along the front, just south of another short wave. If the short wave over Iowa could end up in better position with the front, it could be a decent setup.

 

[jamesmseitz]

I am liking this day more and more. Andrew is right.... that second wave in Iowa could be good. The upslope on the High Plains is always an interesting play. The mountains do crazy things along with the higher elevation. Have had some great chases there in CO and Wstn KS

 

[Jason McKittrick]

Well it looks like it is time for me to get back up on the horse. Last time I chased April 23rd, got 1 tornado to stick to the tape however blew a head gasket of the way home, boo.....

Just looking at the NAM forecast for Monday. Let me be the first to throw this out there, even if NAM moisture is overdone by 5F I believe we will see a Moderate risk for southcentral and southeastern Nebraska.

Nam is indicating backed surface winds along the warm front out of the SE at 20mph veering to the west at 700mb. Storm motions expected to be ENE@25 so training of cells and flash flooding could become a problem however the recent dry weather my mitigate this sufficiently. Capes are forecast to range from 2000 to 3500, SCC 30-40,STP 3-4, 1k EHI 3.5, 0-3km Helicity ~250 m^2/s^2.

I expect storms to initiate from west to east along the warmfront with HP supercell structures initially transitioning to outflow dominate mini bows by mid to late evening. Looks to me like there maybe some development along the dryline in the panhandles as well with at least one good storm somewhere between Stratford, TX and Mead, KS.

I plan on targeting the warmfront between Seward, NE and Grand Island, NE where shear, instability and favorable terrain are juxtaposed.

 

[Warren Faidley]

Barring any issues with moisture transport, Monday and Tuesday should be two of the best chase days in a long time. I believe shear is under forecasted as are CAPE values. Chase area to be determined by surface features... e.g., outflow boundaries on Tuesday.

W.

 

[Scott Hammel]

We will be heading out for tomorrow as well. Initially I like the CO/KS/NE intersection to start but will definitely plan on heading east and possibly south from there. Steep lapse rates and decent CAPE near 1500 j/kg should provide some good hailers. Hopefully cells can remain discrete for a little bit before going linear and becoming a mess. Don't like the tornado chances too much but it will be the most promising thing I've gone after in awhile. We'll leave Denver probably around 8-9 and head for Holyoke and plan on readjusting from there. Just to add a disclaimer, since I'm heading out expect nothing but sunshine...

 

[Andrew Stoller]

Well, the GFS has the shortwave over western NE, and the NAM doesn't. If that wave can verify, along with the front, I'd expect a couple nice rotating storms firing on the Cheyenne ridge tomorrow.

 

[Mark Blue]

I've been so focused on today that I haven't spent a lot of time forecasting for tomorrow. Since we are in SE NE and some of the parameters I've looked at point to Nebraska as the place to be (or at least one of them) on Monday, we will be targeting the I-80 corridor between roughly Aurora and Omaha. I know that's a big area, but I'll narrow it down in the morning. By the way the SPC is talking about tomorrow I'm hoping this pans out as it's our last day for "Chasecation 2009" and so far we've been "bageled". I like some of the wording they used in the SWODY 2 (tendency to remain discreet, substantial veering with height, etc.). We will see you on the road and good luck to everyone.

 

[Bill Schintler]

Chase Target for Monday, June 1.

Chase target:
15 miles southeast of Beatrice, NE.

Timing and storm mode:
Storms will develop from east to west across extreme southern IA by mid-afternoon, and then further west into southeastern NE through 5 PM CDT. A few supercells will be likely early in storm evolution, before transitioning into a linear mode.

Discussion:
The NERN CONUS trough will shift N and E, allowing for an increasingly zonal pattern across the NRN tier of states. In the LLVLs, a CF will extend ENE from low pressure over WRN KS, where it merges with an OFB over SRN IA. A decaying convective complex will track across NERN IA overnight, aided by a veering 45kt LLJ. Convection will also initiate between 09Z and 15Z along an OFB arcing across ERN and SERN IA, before weakening by early afternoon. By mid-afternoon, the OFB-reinforced boundary will lie roughly along US-34 in SCNRTL and SERN IA.

LLVL moisture will increase along and S of I-80, with SFC dewpoints approaching 70F and H85 dewpoints AOA 10C along US-34 with attendant instability increasing to 2500J/kg in SERN NEB/NERN KS. Models generally have a poor handle on ongoing convective trends; however, FCST consensus is high with QPF 21Z-03Z, 06/02/09 across SRN IA and into SERN NEB. By mid-afternoon, convection will reinitiate along the IA/MO border. Shear is once again problematic, with the strongest H5 flow remaining well N of the area. However, FCST NAM/GFS soundings near Lincoln indicate 25-30 kts of deep-layer shear along with moderate SFC-2km hodographs with SRH of 100-150m2/s2, which may be enough for rotating updrafts given the degree of instability.

- Bill
9:04 PM CDT, 05/31/09

 

[Chris Allington]

Glancing through tonights runs... I'd say I'd end up somewhere near Fairbury, NE if I end up heading out tomorrow. Both the NAM and GFS put between 2000-2500 j/kg of CAPE with some decent directional shear. SEly surface winds and WSW 500 mb winds make me happy when you put that stationary front into play. I would hope something could ride a little more SEly into the surface flow and better instability just SE of the region. Since its local I'll wait things out before deciding if its worth a vacation day tomorrow.

 

[Craig McPeck]

Looking at some data, it appears that the best cape will remain from I-80 south, with the best shear enviroment displaced from the strongest cape. I will not be going chasing but if i was making a target, just like my chase today, would target Lincoln Nebraska where some of the shear and decent cape overlap. It also appears that due to the MCS not really forming tonight; though their are some storms, it should not have sufficient power to push this front as far as it would have if their would have been a decent MCS across Nebraska and Iowa. I also see several boundries across central and eastern nebraska along the I-80 cooridor which will help the iniation in the storms. Overall, it seems that all the time their seems to be one ingredient that isnt so hot, and thats the shear, and its just not where the highest cape is forecasted. Though i am expecting the cold front to move down tonight and stall along I-80. Watch out for training of storms, could be a doozy with heavy rain amounts!

Just my 2 cents, i may not have as much knowledge as you guys, but i have my opinions.

 

[Brandon Sullivan]

Im adding IA/MO/IL to the thread for obvious reasons..

will be leavin for SW IA or NW MO in morning..

lots will hinge on location of frontal boundary.. the ongoing convection may keep it further south, which nam/gfs picking up on the further south..

Good Luck All

 

[Adam Penney]

I am planning on chasing tomorrow. Concern tomorrow is yet again the meager flow at 500mb. 25-30kts can hopefully be sufficient to initiate surface based convection along the front.

Moisture should be much better tomorrow, and along with lower LCL's, tornado chances should be better as well.

Im hoping for the best, 2009 = BLAH...lol

 

[Andrew Pritchard]

I don't think there will be any problems initiating convection tomorrow. In fact the opposite it likely to be the problem with too much convection not allowing much in the way of tornado production. Popular target right now seems like SW Iowa and NW Missouri, but I may play on a hunch on se Iowa near Ottumwa. Best instability/moisture/upper level support is going to be in the eastern target zone in SE Iowa/W Illinois. Low level shear is not as strong there, but the likely presence of an outflow boundary interacting with the stationary front could help things quite a bit. Just not impressed enough tonight to drive -too- far west for this one. I'll probably pick either a Kirksville, MO or Ottumwa, IA starting point based on position of surface front / ofb in the morning.

Not really day that you can "model chase" very much. Going to have to rely heavily on real-time data.

 

[Scott Hammel]

Not really day that you can "model chase" very much. Going to have to rely heavily on real-time data.

I completely agree. I've changed my target so many times on this that basically now we are heading for Kearney, NE and will just adjust on the fly. Bring your rain jackets...