6/2/08 FCST: KS/MO/IL/KY/AR/TN/IA

[Ben Prusia]

0Z runs of both the NAM and the GFS models are indicating the development of a secondary weak surface low and a northward moving warm front ahead of a dryline/stronger surface low (997mb) during the day on Monday. The secondary surface low progged to be in eastern Kansas and associated warm front extending into Missouri look to be the only play in the day as areas nearer to the deeper surface low and dryline should remain well capped.

The models are forecasting 70 degree dewpoints east of the dryline and south of the warm front. Atmosphere should become moderate unstable ahead of the dryline with CINH readings approaching 0 near the secondary low and warm front. Feel that best chances for tornadoes would be nearer the secondary low where winds can remain locally backed. And that is if we can get the cap to break...as areas nearer the secondary low and points west will have to deal with 700mb temps at or exceeding 12 degrees celsius.

SPC has already outlined a majority of Missouri with a 30% hatched SVR potential for tomorrow with a potential upgrade to moderate risk.

 

[Colin Davis]

0Z runs of both the NAM and the GFS models are indicating the development of a secondary weak surface low and a northward moving warm front ahead of a dryline/stronger surface low (997mb) during the day on Monday. The secondary surface low progged to be in eastern Kansas and associated warm front extending into Missouri look to be the only play in the day as areas nearer to the deeper surface low and dryline should remain well capped.

The models are forecasting 70 degree dewpoints east of the dryline and south of the warm front. Atmosphere should become moderate unstable ahead of the dryline with CINH readings approaching 0 near the secondary low and warm front. Feel that best chances for tornadoes would be nearer the secondary low where winds can remain locally backed. And that is if we can get the cap to break...as areas nearer the secondary low and points west will have to deal with 700mb temps at or exceeding 12 degrees celsius.

SPC has already outlined a majority of Missouri with a 30% hatched SVR potential for tomorrow with a potential upgrade to moderate risk.

Glad you started this thread, Ben.

As of the 12z, I LOVE this setup. Winds are much better than they have been for the last week -- backed, strong 850s and SFC; SRH maxes out in E KS/W MO at 0z with pretty decent instability.

I don't see the cap being a HUGE problem per se. In fact, in E KS...I see it holding on just long enough to be beneficial.

As of right now, give me the Manhattan, KS area or maybe a bit northeast. For a day that I didn't expect until looking at the D3 yesterday, I'm rather impressed.

 

[Andrew Pritchard]

Looks like a decent shot for supercells and tornadoes tomorrow across NE Kansas or southern Nebraska. I've already committed myself to getting up early and making the drive over tomorrow (this time of year only comes once, what the hell). Right now probably targeting the Manhattan area along Interstate 70. Maybe a little better kinematics further south, but doesn't look like the cap wants anything to do with eroding down there.

Vertical velocities are spiking with an eroded cap and surface cape of 3500 j/kg around Interstate 70 near Manhattan so I think that's as good a bet as any for some supercell activity.

Biggest concern now is slightly anemic flow at H7 and H5 the further north you get. If we can hang around I-70 we're still looking at around 45 kts of 0-6 km shear which will do supercells, and helicities at 0-3 km are peaking around 400 so tornadoes should be a threat if we get deep convection to fire.

Debated on this day for a while tonight but who knows how long the pattern and my finances will allow so might as well go all out this week.

 

[Bill Schintler]

Chase Target for Monday, June 2

Chase target:
Belleville, KS

Timing and storm mode:
Storms will develop in the target area at 5 PM CDT. Supercell storms capable of a few strong tornadoes will be possible, especially between 7 PM and 9 PM. Storms will later evolve into a large convective complex and track east along the IA/MO border during the overnight hours.

Discussion:
The flat SRN stream ridge will amplify slightly over the next 24 hours, while a couple of impulses move E within the stronger H5 flow. A lead impulse will overspread MO between 18Z and 22Z Monday while a secondary but weaker lift mechanism should follow in its wake and provide sufficient UVM for initiation as convective temperatures are reached. Looking at MDL performance, both the WRF and GFS have apparently initialized several degrees too high with regard to SFC dewpoints in NERN KS, where dewpoints of 55-60F have verified at 00Z.

FCST will once again be a challenge due to the uncertain evolution of at least two convective complexes between 03Z and 15Z. Convection currently underway in NRN through NWRN NEB should expand in coverage and track ESE during the evening on the nose of a 30kt LLJ, but will decrease in intensity after 06Z as the LLJ refocuses further S. Between 04-06Z, a second smaller MCS may develop over SERN NEB and NERN KS. At 3:30Z, weak returns were beginning to show up near the KTWX site, however latest MDLs indicate the LLJ will remain focused further W. Outflow associated with this and the activity over NEB will be critical to timing and location of renewed convection Monday afternoon. Current reasoning suggests that an OFB will push S to a Kearney, NE; to Manhattan KS line by 14Z. This boundary will effectively merge with a synoptic WF and then retreat slowly to the NE, while a DL mixes EWD and reaches a Goodland to Dodge City line through 22Z.

Of concern is timing of forcing, with subsidence within the wake of the aforementioned lead impulse. UVM will increase in NERN KS after 22Z, however, and spread SEWRD through 01Z. Backed 20kt SFC flow and an intensifying LLJ will result in large hodograph curvatures, especially after 01Z with SFC-3km SRH AOA 500m2/s2. Further W along an advancing DL and near a WF/DL triple point, strong thermal ridging with H7 temperatures AOA 14C along with weak forcing should suppress SFC-based convection.

- bill
11:00 PM CDT, 06/01/08

 

[Mike Hollingshead]

I think I'm going to have to take a trip west tomorrow to central NE.

http://www.wxcaster2.com/CENTRAL_ETA_SFC_SLPTMPDPTWINDSLI_24HR.gif

Figure storms could fire off that boundary near the SD border arcing sw, then drop southeast off of it.

Thedford 0z FCST Sounding

Ainsworth 0z FCST Sounding

A storm in that environment would likely prove intersting, especially with no real strong sfc forcing. Just has that feel of a day where storms pop out there and drop se as flying eagles for a few hours. Big cape, great turning and lovely vent. 4km NMM WRF doesn't like it, but that's fine with me. Also, should maybe be some outflow boundaries to perhaps serve as initiation points.

Target: Brewster to Broken Bow.

 

[Brian Stertz]

IMO need to add NE Colorado and W. Nebraska to this thread. Things look very scary for tornadoes and punishing hailbombs with good upslope component and mid-upper Td's into High Plains.

 

[Darrin Rasberry]

Color me unimpressed for Iowa as of the 00z. I guess that massive flood-causing MCS must've stolen the instability outta here for a while. Decent helicity, temps/dews,temps aloft ... perhaps a lifting mechanism could be needed but whatever - it doesn't matter. You can't do terribly much with no CAPE.

GFS has poor moisture depth at 850 and a feature in SE Iowa that the WRF doesn't see. GFS also breaks out much less precip, and is less confident pushing the dryline than the WRF.

Assuming the WRF, I like the bulge in KS on the dryline but it's pretty hot there IMO. Good instability north of there so maybe there could be some storms that pop along the NE/CO to NKS/CO border if elevated yard trash doesn't steal its thunder from down south first. Otherwise I don't see what's going to kick these things off in the sector away from the dryline. Would be interested in seeing what the more knowledgeable think of this; IMO it is a bit difficult to read for a beginner like myself.

 

[Andrew Stoller]

Looks to me like capping and CINH will be a big concern tomorrow, especially the further west you go. 700 mb temps are in the 18 to 20 degree range. Nothing broke through that in NE CO today (6/1/08)! And as soon as storms that formed in the cooler mid levels reached the high 700 mb temps, they went poof.

The previous WRF run had a slot of cooling right around Goodland at 00z but now it's back to an oven.

Things are cooler in NE though. The ridge over the south central US/Texas needs to get out.

Based on this, I'd head for the NE panhandle again today, maybe even further north into the Black Hills. Models again today break out precip in the higher terrain north of the Cheyenne ridge, and any kind of convection further south into CO/western KS holds off till 03z after things cool off a bit.

 

[Derek Weston]

Color me unimpressed for Iowa as of the 00z. I guess that massive flood-causing MCS must've stolen the instability outta here for a while. Decent helicity, temps/dews,temps aloft ... perhaps a lifting mechanism could be needed but whatever - it doesn't matter. You can't do terribly much with no CAPE.

GFS has poor moisture depth at 850 and a feature in SE Iowa that the WRF doesn't see. GFS also breaks out much less precip, and is less confident pushing the dryline than the WRF.

Assuming the WRF, I like the bulge in KS on the dryline but it's pretty hot there IMO. Good instability north of there so maybe there could be some storms that pop along the NE/CO to NKS/CO border if elevated yard trash doesn't steal its thunder from down south first. Otherwise I don't see what's going to kick these things off in the sector away from the dryline. Would be interested in seeing what the more knowledgeable think of this; IMO it is a bit difficult to read for a beginner like myself.

Yeah, pretty easy to see what is wrong with Iowa....little CAPE or upper level wind support to work with tomorrow -- everything is further west. Perhaps western Iowa will see a few things fire late... but more likely just MCS junk overnight.

As for the other areas... (as I'm reading it...)

Based on the WRF/NAM.... You've pretty nice directional shear from W/C Nebraska through E Kansas... Of concern are weakish mid level winds. And the 850s through Nebraska aren't of exceptional intensity.

The NE corner of Colorado ought to have some decent dews, and considering nearby placement of the low, might hold some interesting potential.

What is going to kick things off away from the dryline/coldfront? Watch the warm front... Outflow boundries could be of interest too.

Really short based on looking over latest NAM:
Likes: Directional shear, CAPE
Dislikes: CAP/timing issues, possibly weakish mid or upper level flow. (upper through Neb -- fine in KS)

I think NC to NE Kansas really has some potential if things fall into place...

 

[Mike Peregrine]

Satellite is just a mess of MCS debris this morning across almost all of Nebraska and most of northern Kansas. Finding sun-reinforced instability seems like it would be troublesome today. The SPC seems to feel that the ongoing MCS should gain strength/intensity as it approaches the Missouri River valley. I'm not a fan of these situations. Embedded supercells within clusters are hard to pick out, and even harder to maintain enough isolation to produce something of real interest. Guess I'll be watching satellite all morning. The good news is that these ongoing storms should be making the cap more pliable, so I wouldn't think that would be as much of a concern as it looked to be to me last evening. After looking at this, I almost think west is the better option, if a person had time for a trip to eastern Colorado or western Nebraska. Tough call -

EDIT - looks like the clusters around Jewell/Republic counties and vicinities are indicating TVS signatures on the southern ends of several cells now. Ugh. The one going into Cloud county is showing 74 kts of gate-to-gate shear. Nice.

 

[Chris Hayes]

With all the cloud cover remaining over western and central Nebraska, I'm glad I've opted to remain in Salina for the day, and hope to catch some storms that form over NE KS, SE NE. There is some clearing across this part of the target area. Hopefully it'll be enough to provide enough instability to break the cap ahead of the WF later this afternoon. Trying to find an outflow boundary that may have been left behind the MCS over eastern KS and western MO, as that might provide additional focus for development this afternoon. Good luck everyone venturing out.