5/12/2010 FCST: IA/MO/KS/OK/IL

[cstrunk]

Well I know everyone was pretty focused on the event on Monday. Tuesday and Wednesday may have potential as well. This thread will be for Wednesday because it's the day I'm looking at as my next possible chase.

The NAM and GFS place a surface low somewhere in the NE/IA/MO/KS border region. The NAM is about 50-100 miles farther north with the placement of surface features than the GFS. The NAM has a warm front stretched out across the IA/MO border and what looks to be a cold front crashing in through central KS and points SWWD. Both models are pointing to dewpoints nearing 70F and there will be sufficient CAPE along the cold front, with less available along the warm front.

I'm very new to forecasting and just wanted to get some discussion started for this day. Curious to hear what others have to say.

*Edit - It looks like I should have listed the date first in the title. If a mod sees this, could they correct it? Thanks.

 

[Matthew Piechota]

I would also add IL to this thread as atleast west central IL could be in play for svr on weds. Just saw that SPC just put out a 30% hatched area and the setup does look interesting.

have 50-60kt flow at H5 out of the WSW to almost due west with slightly veered winds at H85 in KS but have more of a southerly component to them in IA/MO over top a nice theta e rich environment with CAPE values between 2000-3000 j/kg with dew points in the mid and upper 60's along and south of the warm front.

will look more at the setup tomorrow as I have been up studying for finals and now time for bed.

 

[cstrunk]

Yes, Illinois should also be added to the title.

It looks like the cold front will be crashing southeastward, so not looking good there. The warm front looks like a decent play, just need to take a closer look and see what part along the front looks best.

I'll see how the models differ tomorrow and try to get some idea of a target tomorrow. I may be starting in the St. Joseph, MO area due to other activities. But I'll be ready to go on Wednesday from there, and would be interested in teaming up with someone. Send me a PM if anyone is interested.

 

[Jason Berner]

Taking a quick look before bed the current NAM shows storms firing up between 18 & 21z on Wednesday (of course it has to be right during one of my atms finals). Looks like all the conditions are atleast present for some strong storms and some possible supercells. Dewpoints will be up near 70 with CAPE values of 2500-3000 J/kg over good portions of KS/MO/IL. Sfc-500mb bulk shear of 50+ kts should be sufficient to get some of the storms spinnin. Storm motions along the warm front are not unexpectedly much slower than we have been seeing out on the plains. From what little I've looked at, it looks like you could def. see some chaseable storms out of it but I think your biggest threat will be more the hail and wind...especially with the possibility of more elevated storms along the warm front.

I'm interested, atleast, in looking at this more tomorrow and wed. morn. to see if it is something worth tryin to get out on later in the evening. It's not as often we get to see some of the fun stuff I get to watch on live streams out this way but hopefully it'll pick up more here in the next few weeks over here. Hopefully a few more people start to chime in with their forecasts so I can continue to learn and get better at forecastin this stuff.

 

[jeremy wilson]

Hmm, this feels like a sleeper day to me. Forecast hodos for low level shear look nice in e central kansas on wednesday. Cape looks awesome and at they won't be moving at warp 6. I'd bet on a few spinups along The front somewhere and i'll get a nice light show on The way back to texas.

 

[Jason Haller]

This day is look okay to me. The biggest question for me is if the atmosphere will recover from the storms that are in the forecast for tonight and in the morning hours Wednesday. Looks like a good chase day for my area with storms firing just to me east if the models prove out.

 

[John Farley]

Looks like a potential play across northern MO possibly into west-central IL along the warm front - very good combination of shear and instability right along the front so if a storm gets rooted in the front tornadoes could be a possibility. NAM has EHI as high as 6 near the front in north-central MO. One concern for me is that the NAM doesn't break out much precip except well north of the front where storms will be elevated and well south of it where the shear won't be maximized. But it certainly looks like a potential chase day to me.

 

[Robert Reynolds]

I'm liking the current 00Z Nam for the Kansas City area, although it did look a little better last night. Nearing 3000 CAPE, LI's -6, 3 km EHI 3.2, and low LCL's/LFC's (354 m/516 m, respectively). GFS shows similar, with slightly higher CAPE but more CIN. Helicity is not overly impressive at the movement, but we'll have to see what future runs hold.

 

[Ryan Wichman]

Here is an excerpt from the latest CA forecast:

The noxious trough that has been responsible for the past few days of active weather on the Plains will start to eject eastward towards the Great Lakes on Wednesday. With the ejection of the trough, a low pressure system will move into the Kansas City area by midday Wednesday. A coterminous warm front will be draped across the Missouri Valley, extending roughly along the U.S. 36 corridor from St. Joseph, MO to near Springfield, IL.

While both the NAM and the GFS are fairly harmonious in regards to the position of the warm front (per the 12z run on Tuesday), the GFS is a soupcon south of NAM in it’s placement of the frontal boundary at 21z on Wednesday. Per the surface maps shown below, the triple point is progged to move across northern Kansas, and should eventually reach the KC/Cameron area by 00z.

Although upper-level dynamics are not overly vivacious, low-level hodographs will enhance the ability of storms to become tornadic in the vicinity of the warm front, should any storms develop in the warm sector and interact with the frontal boundary.

While 700 mb temperatures will be increasing throughout the day Wednesday, due to a more studious EML advecting into the region, if storms do develop in the warm sector they should be isolated or scattered in nature.

You can read it all here: http://convectiveaddiction.com/2010/05/11/fcst-051210-ksmoil/

As a side note, I am a bit concerned about the lack of precip breaking out. But tomorrow it should become obviously whether or not storms will fire east near the Mississippi River.

 

[John Farley]

This evening's NAM run would suggest a potential play in east-central MO or west-central IL just northwest or north of the STL area. It breaks out some decent precip by 21Z and moves it over the warm front just north of STL, in an area with CAPE around 3000 and decent directional shear, especially near the front. This is probably getting down to too much specifics this far ahead, but if this scenario plays out then the general area from around Roodhouse to Pittsfield, IL would be a good play. One challenge in this area is that if you are on the wrong side of them, both the Mississippi and Illinois Rivers are in that general area to spoil your day, with very few crossings. So if this area is the general play, just east of the Illinois River or somewhere right by a bridge over that river (i.e. route 106 or I-72) might be a good place to set up.

EDIT - Local TV mets and NWS St. Louis and Lincoln discussions indicate thinking that capping will prevent daytime storms except perhaps much farther north. GFS also is consistent with this thinking, in fact breaking out very little daytime precip anywhere in MO or IL. But the NAM as I earlier mentioned breaks out precip just NW of the STL area then moves it up through the central IL area near where it positions the warm front. So again we have some model disagreement. Hopefully things will be clearer in the morning, either supporting the west-central IL target, suggesting a trek to northern MO, or suggesting don't bother. No doubt instability and shear will be supportive of tornadoes near the warm front if storms can develop, but at this point I would say it is not clear that they will.

 

[Chip Redmond]

Right now am heading through Illi on 64 shooting west. A couple chase days on our way back so we figured what the heck. Initial target was Columbia since it was going to be right along the warm front and was hoping for storms to ride the frontal boundary. With the 0z run, it appears the other boundaries we were hoping for from the morning convection will not be significant as the precip sheild will be so expansive that no significant boundaries will be laid. There is also a big difference in the initiation guesstimations in the models as mentioned before that questions just where or if any boundaries will be remaining.
With a impressive streak at the 500mb level at 65+ knots in western MO, along with a triple point as mentioned earlier, feel this area will be better sheared. With frontal forcing convection is nearly guarenteed but timing remains an issue (hopefully it occurs before night). It will be interesting to see the cloud cover situation in the wake of the crapvection. Instability shouldn't be a problem as long as the sun makes an appearance. This will hopefully be slightly better chase territory (I hope, since I've never been to this part before) than the original target. The only thing that bothers me is the road situation in that part of the state. I suppose we will see what happens.

Chip

 

[Mike Peregrine]

Guess I'll try my hand at a forecast here. The 6hr HRRR is showing what looks to be a storm developing by 1800 south of Lawrence, with lots of leftover debris in eastern Kansas/central Missouri. EMC 4.0 km WRF simulations also look cluttered, but shows what looks to be possible supercells along the boundary to the south of Lawrence/KC, moving across the metropolitan area. NSSL's WRF places what looks more like an MCC further south in SE Kansas, moving swiftly across Missouri between 08-12hr runs.

I wonder about the timing of best helicities arriving to the area and storms not being able to remain isolated, and also the degree of cloud cover leftover this afternoon from early morning convection. For now I guess I'll assume that we will see some sun in the warm sector at some point this afternoon and lean toward the area between Lawrence and Emporia, possibly following storms into the Kansas suburbs (during rush hour).

EDIT - if isolated supercells do fire, I can definitely live with 25-30 kt fcst storm motions easier than the stuff on Monday ... storm motion was my sole deciding factor in sitting that one out. I'm getting too old for the fast stuff!

 

[ABlaser]

Totally agree mike, homey here don't get into 50kt storms no more

 

[cstrunk]

I'm not liking all of the cloud cover so far around the Kansas City area, but I suppose it is only 10:30 AM. Some breaks in the clouds can be found to the south and southwest. Hopefully we can get some more of that to burn off.

As it stands, I think Emporia, KS would be a good target. I'm still in St. Joseph, MO. I'm going to have lunch and probably make the decision to head farther south after I take another look at things.

If anyone is interested in teaming up, let me know.

 

[Mike Peregrine]

Totally agree mike, homey here don't get into 50kt storms no more

Yeah, just never seems worth it ... especially with seven gazillion chasers around. You shouldn't have moved back to ICT so we can start our own 40 year old chase team. But we'll have to talk about that in another thread ... lol.

Here's a snap of vis sat for kicks:

There is some breakage in the zone, but why am I still not excited about today?

This seems like such a take or leave sort of thing to me ... I'm just not sure of there being a decently sheared environment at the time of initiation, I guess. Maybe we'll be pleasantly surprised. But right now I'm just not groovin' on this one.