10/22/04 FCST: Plains/midwest

[Robert Dewey]

Northeaster KS and southwestern NE looks like the best bet at this point. Cloud tops in southwestern KS appear to be warming, but I am doubtful of any sunshine given the high RH values at pretty much all levels...

The best area looks to be between just north of LNK, NE to down to SLN, KS - RUC soundings reveal that a SFC parcel of 72F/66F yields 2300-2500J/KG of CAPE across this region, with a ESE SFC flow, and excellent speed shear. 12Z ETA has even better shear in this region, but odd looking SFC parcels (temps nearing 80F, and still a small CAP). Helicity on both models is up near 350m2/s2 across the initation region. Since storms will be initiating in this area, supercells are more likely than areas further east, where convection should be predomently linear by the time it gets there.

Other than that, like I said, I would place bets on eastern/northeast quadrant of KS and southeastern NE...

Will see how this works out (or doesn't)...

 

[Shane Adams]

I'm still at home here in OUN watching things evolve. Not thrilled at all by the profiler data I've been seeing, and SPC's composite page paints ean equally-disheartening picture. Not much LL veering at all, so tornadoes look like an extreme longshot. There's already isolated stuff developing down in NW Texas ahead of the grungeline, and they're moving into an area of maxed CAPE. I'm still not convinced it will matter because of the crap wind fields, but I'm continuing to monitor.

My plan was to remain south of the line, and the Texas activity is the reason why; I believe that's the best area for any possible tornadic activity today because of the maximized heating and CAPE, plus the fact that there's still a lot of "room" ahead of the crapline for isolated storms to develop and flourish. I'm betting on the oddball storm ahead of the line in that region today, otherwise I'm not spending any money or doing any driving - win/win for me.

 

[Bill Schintler]

Chase target for today, October 22

Target:
Marshall, MN.

Timing:
4 PM.

Storm mode:
A few compact supercells early in storm development, with some F0-F1 tornadoes.

Discussion:
A few tweaks from 00Z discussion. As expected, the CI shield is lifting slowly to the east, leaving an extensive area of ST over the FA. The stratus was starting to erode in CNTRL NEB. Latest guidence trends away from a dryline along the MO river, and the primary boundary now appears to be an E/W oriented WF which will become defined in SW MN late in the day. Instability is marginal, however it appears as though a small area of CAPE to 1000 J/kG is possible in this area providing erosion of the ST and a small window of insolation. Shear parameters are impressive. SRH values in excess of 450 will be found along and NE of an Estherville, IA to Watertown line. Very impressive large curving hodographs will be found in this area between 22Z and 00Z.

bill

 

[Tim Stoecklein]

Not to burst anyone's weather balloon( :lol: ), but we're seeing some small stuff firing to our west here in Manhattan and it's moving NE at 50mph!! Better hitch a ride with Mike H in that speedy Mustang to keep up today.

Tim

 

[David Draun]

Blaaaahhhh. What a dreary, damp day, definitely not conducive to storms right now, especially here. It's humid though, if you don't count the cold. 52/48 T/Td. I don't see it reaching above 60 this afternoon, with all of the low and high stratiform crap. What a disappointment. I would have liked to see a MDT risk today with hatched areas and everything. RUC 6 hour DVN sounding is making me laugh right now. Conv temp is 96 degrees, and estimated max is 83. HA HA HA. I don't see it happening at all. Storms will definitely be elevated if they develop. Thermonuclear cap anyone?

The 12 hour ETA for my area (LOT) is also funny as hell with high forecast max temps and convective temps. CIN is well above 8000 J/kg. Nice LCL though, but the LFC is -1mb. How? Never seen a negative LFC before.

Area forecasters mention a rainy night probably from an mcs or something. (MCS in lower case, to emphasize crappiness) What's that system next week supposed to be like?

 

[Stuart Robinson]

Well the SPC just issed a MD for NE KS, SW NE for ELEVATED thunderstorms

http://www.spc.noaa.gov/products/md/md2349.html

 

[Amos Magliocco]

I'm just west of Emporia. There's good news and bad. Good news is SVR warnings both north and south KS. These storms are fast because they're elevated above the cap, but their intensity suggests steeper lapse rates than we'd foreseen. Air mass is primed. More good news: some areas of cloud cover are thinning. I saw the sun on my trip from Lawrence down here--not clearly, but through the thin cirrus. Note vissat image with clearning near Manhattan and note sfc temps there on latest chart. Pool of upper 70's near the clearing; close to what Roger named as our convective temp for sfc-based in his MCD. Dryline sufficient for lift, I think, between here and DDC.

Bad news: cloudy and capped. 11:30 and no real insolation yet. October. LOL. Low levels too veered; too little SRH. So on and so forth.

But I'm still glad to be chasing. It's great to be out of the forest for a while!

 

[David Draun]

Well the SPC just issed a MD for NE KS, SW NE for ELEVATED thunderstorms

http://www.spc.noaa.gov/products/md/md2349.html

They are expecting surface based thunderstorms later. The CAPE and steep lapse rates above the inversion layer they mention are pretty good IMO. 2000 J/kg-3000 J/kg is not too shabby.

 

[Mike Peregrine]

Vis sat is showing clearing in NE Kansas now ... fairly substantial around the Marysville-Concordia areas. I will probably head somewhere between Marysville and Beatrice this afternoon. As David mentioned, though this is remaining elevated now, it is expected that storms will be able to become rooted in the boundary layer as the day progresses. Hopefully won't be too late. And hopefully storm speed will slow. I am more hopeful now that I see the stratus deck giving way to thinner cirrus coverage closer to home. Amos may have to wait a bit longer for insolation in the Emporia area, as fairly heavy stratus appears to still hold an envelope further to the south. Also wondering if this line that is visible on the back side of the cirrus canopy (Western KS) may turn out to be convective in nature? - If so we may see the development of a linear event.

 

[Mike Peregrine]

How interesting is this ... 1630 showing 5% probablistic over TEXAS now -

THOUGH DAMAGING WINDS AND LARGE HAIL WILL REMAIN PRIMARY THREAT...SHEAR IS MORE THAN ADEQUATE FOR SUPERCELLS WITH SUFFICIENT LOW LEVEL SHEAR/RH IN PLACE FOR A THREAT OF TORNADOES ONCE STORMS ROOT INTO THE BOUNDARY LAYER THIS AFTERNOON

Fast moving CF in Kansas may cause problems in producing a decent show here if it undercuts the boundary layer too sharply, too quickly. I'm guessing we'll see a squall line here ... but still guessing.

 

[Mike Peregrine]

RUC model forecast showing SRH looking quite poor -

http://beta.wxcaster.com/models/RUC/CENTRA...KM_SRH_09HR.gif

This seems to jibe with ETA, which shows better helicity to the north -

http://beta.wxcaster.com/models/eta/centra...KM_SRH_09HR.gif

SBCAPE:

http://beta.wxcaster.com/models/RUC/CENTRA...S_CAPE_09HR.gif

500mb winds are trucking today - 55kt in NE Kansas ... yuck.

Concordia forecast Skew-T with ETA/GFS/MM5:

http://www.wxcaster.com/modelskewts.php3?f...STATIONID=72458

Emporia:

http://www.wxcaster.com/modelskewts.php3?f...&STATIONID=KEMP

 

[Scott Olson]

Threat is materializing for Eastern South Dakota, NW Iowa and SW MN...
They put me in the 5% zone here in Brookings on the Border with Iowa. And seem to suggest that the lack of QPF modeling is the only reason stoping a moderate risk. Still im going to goto Sioux Falls and use the public doppler monitor at the east mall. Still think the real potiental is on the nose of the jet which should be a bit more east. Watching to make sure the dry punch evolves as planned, still pretty cold here and nice layer but once it starts breaking temps should rise fast. Most likely chase target is going to be about 30 miles east of Sioux Falls on the border of IA/MN. Things should get interesting as of 21z, hopefully quickly cause the sunsets here not to long after 23z.

 

[Dan Christianson]

what to do"?

:?: Well it looks like another day of CLOUDS CLOUDS CLOUDS im not an expert on alll the weather analysis, im seeming to think IA is a best bet for chasing, even if the tornado potential is North and into MN"? i see a nice storm in MO but prb jsut a heavy rain producer, if i was to pick an area for chasing id say I-80 east and I-35 cooridors.... anyone think things will get intresting by 2pm or earler? im pretty sure we will see something jsut a feeling but then again who know's


any thoughts"....


dan.c

 

[Mike Peregrine]

Yeah - that storm in NW Missouri is elevated ... though it has grown substantially. It's also moving at about 50kts to the northeast ... no fun.

 

[Robert Dewey]

I don't think things are lookin so hot for today...

If I was out chasing, the best are still looks like northeast quadrant of KS, southeastern quadrant of NE, extending into southwest IA and northwest MO... Helicity isn't as good as further north, but it's decent at 250-300m2/s2. As expected, mid and upper level clouds are streaming northeast ahead of the main 500mb low, with low level clouds filling in rapidly just southwest of MN. Even so, SFC temps are already in the mid to upper 70's with dewpoints in the mid 60's across the KS region, which yeilds CAPE in the range of 2250-2500J/KG through the afternoon and evening, with a 1C cap at 850-700mb.

The dryline is expected to punch eastward, at the same time the 500mb jet edges into the region, with the tightest gradient/best moisture convergence centered on the eastern KS/NE/MO region later this evening (21Zish), which will likely overcome the CAP and allow storms to become SFC based - Thus I think the best threat is still in that region. Supercells look like a good threat, but not necessarily tornado producers...