2/24/07 FCST: OH/KY/TN/IA/KS/MO/TX/LA/OK/IL/AR

[Kevin Askew]

Very good points. Makes me nervous but will be out in a force of 2 chase/spot vehicles I imagine. Any instibility is really going to make this a dangerous setup. I do anticipate a high risk on 2 days of events. Just too many dynamics present. We have seen these set ups here & know what & how many episodes of severe weather can happen. SPC dont have all the way north to Kankakee IL. in severe weather threat for nothing. Thats the startling thing about this system. Just dont know how the dynamics will pan out against the lack of instibilities? Will be interesting to say the least.

 

[Scott Lincoln]

So with this said, an EF 5 is VERY possible in the KPAH warning area. Sat or sat night. Yeah that sounds like a soothsayer but if history repeats itself we will have a nearly definate outbreak of tornadoes in this neck of the woods.

As a forecaster I would believe it to be a little irresponsible to make such a speculation, especially for a system that wont be in the plains for 4 days...

 

[Jesse Risley]

The dynamics certainly look favorable for a severe weather episode of some degree, somewhere in the central or south central part of the nation. However, let's remember that this storm system is still off the coast of the U.S. and all of this data is based solely on computer models. I think some of this hype is just preliminary anxiety, but I'll chalk that up to a case of chaser withdrawls from last seasons dry spell. We'll see what happens here in the next few days, but predicting major tornadoes this far in advance is somewhat jumping the gun to say the least.

 

[Brandon Sullivan]

Just FYI. Is anyone aware of the extra aircraft/dropsonde data over the north pacific... The new Winter Storm Reconnaissance/WSR07 Project. They fly over and can take data and input it into the models.. It seems to be helping the GFS pretty well. Especially the 0Z GFS. Im not sure if that data has been put into the ECMWF or GEM... Basically, it helps put real data into the models for those systems that arent even on shore yet. So models arent completely making wishcasts.. lol

But on to my forecast.. Im still looking for an event.. But instability has been lacking.. Shear is very impressive, with Helicity values off the charts.. I personally agree with whoever said earlier that the instability is not handled well by the models.. I think with the moisture and and other factors, the instability particularly the CAPE will be higher than forecast. Looks like a problem could be the storms going linear.. With some mini supercells and the usual 60+ mph and 1 inch hail. Early in the day, in OK TX AR MO KS may see some supercells before it goes linear. Were getting near the time when models should begin to converge on a solution... Also, tomorrow the area will be in the SPC 3 day outlook. So we can all get more detailed forecast from them!

 

[beaudodson]

Man - KPAH wind fields before the squall line hits

http://www.usawx.com/13076439041561pahsaturday1.gif

http://www.usawx.com/213154669190807paducah2.gif

 

[SteveCarter]

For what it's worth...lol....the Weather Channel has said, and I quote, "Expect Tornado outbreakS this coming weekend'. As previously stated by numerous people..the concern seems to be the moisture content. The dynamics are setting up beautifully, but IF this does proceed as fast as some models are indicating, moisture may have a hard time catching up to the entire event. Having said this, I'm leaving South Carolina and my initial set-up point will be Paducah, Ky for Saturday. I seem to be out of line with most here, but....Paducah to Memphis seems to be..Imo...where to be. Who knows tho, huh? For those of us who are pretty good chasers, but not the best when it comes to scientific terms, where do you expect the main low to be as of Saturday 0600?

 

[Skip Talbot]

Having said this, I'm leaving South Carolina and my initial set-up point will be Paducah, Ky for Saturday. I seem to be out of line with most here, but....Paducah to Memphis seems to be..Imo...where to be. Who knows tho, huh? For those of us who are pretty good chasers, but not the best when it comes to scientific terms, where do you expect the main low to be as of Saturday 0600?

Steve, I'm a little curious as to your thoughts on a Paducah target. The moisture axis and instability isn't forecasted to move into that area until about 6z Sunday, well into the night. The terrain down there is just wicked, I hope you have some experience with it. It just frightens me that you're going to drive from South Carolina to chase the jungles of the Ohio river valley at night. Maybe you're seeing something that I don't?

I was thinking more along the lines of south of Topeka at 18z Saturday. Given the extreme dynamics and lack of inhibition this will probably be an early show, so I'd like to be in place before noon. I'd like to get right next to the low on the warm front as Davies suggests in his cold core paper. I'm not sold on the chaseability of this setup though.

 

[Bill Tabor]

0z run NAM and GFS have poor dewpoint return up north. It's starting to look pathetic. I may have to back off my prediction of the first High risk. This may be a moderate at most.

Friday may be a better day, but moisture doesn't look too good then either. At least there is some cape forecast to be generated though.

 

[Perry Williams]

IMHO, if there are any violent tornadoes with this impending event, they'll occur somewhere between extreme east Texas and southwest/ west central Alabama.....with the highest risk in central/northern Louisiana and central/ southern Mississippi late Saturday afternoon into Saturday night. Not only does this appear to be an area which will lie underneath an extremely favorable jet (diffluence above 300 mb; strong mid-level dry punch); but is also the most climatologically favorable location in America during the month of February for a major tornado to occur. Based on prior tornadic events I've either witnessed (2/21/93) and researched (2/19/1884), dewpoints in the 60-64 degree range will be more than sufficient for formation of intense tornadoes in such an overall favorable synoptic situation...

 

[SteveCarter]

I'm a little curious as to your thoughts on a Paducah target>>>

After looking at the latest NAM and GFS models....grrr...Paducah may not be so good afterall, but honestly....I'm getting more confused as time goes by. I wondering if there might be a secondary low forming somewhere in western Texas that could boost a shot of moisture into the main low. GFS models have the low (the big one) moving from NE Kansas into central Illinois...thus my Paducah theory. NAM has it going from southern Oklahoma into southern Illinois. I think the dewpoints will cooperate in this this, but as always...everything changes with every forecast. I know the Paducah area very well tho, and love the flat prairie topogrophy from there into Illinois. So...for the time being...lol until next forecast....I'm now moving a little south into the Dyersville TN area to the boothill of MO. Thing is....darkness. Won't even try that one. Any thoughts about YOUR target areas Friday 1600, and Sat 1600? Or the possibility of a secondary low forming?

 

[Mike Hollingshead]

0z run NAM and GFS have poor dewpoint return up north. It's starting to look pathetic. I may have to back off my prediction of the first High risk. This may be a moderate at most.

Friday may be a better day, but moisture doesn't look too good then either. At least there is some cape forecast to be generated though.

Sat 6am gfs TDs.....before precip gets into the model thoughts too much

Sat 6am gfs sbcape...GFS

With the high likelyhood of heavy precip in the a.m. I'm not sure you'll ever see what you "want" to see on the model. Enough moisture should be in place for the cold core event, and I doubt the heavy precip will kill it off. And if it's not as bad as it thinks with precip, I can't help but imagine more than enough moisture and instability will be in place for this(it's nice it does't take much lol). This isn't some new signal on this run.

They "weren't there" the last run, just like this one: 12z gfs run for Sat noon

My early target is now Salina....obviously early.

Edit: And this might be worth a look as far as moisture making it north(according to the model) 0z gfs run 6am

ECMWF has been very similar to the current 0z gfs with the sfc low track.

 

[Paul Knightley]

For Saturday, I think I'd play the cold-cold set-up in E or NE KS/NW MO, just NE of the main 500 hPa low...GFS 06Z/ECMWF 00Z in broad agreement on this region.

 

[Michael O'Keeffe]

The 00Z ETA showed the triple point over SC/SE KS. The area across SC/SE KS into SW MO is primed for low-topped tornadic supercells by late Saturday morning into the early afternoon. Though moisture will be meager a few supercells will be able to sustain themselves in to low-mid 50 dewpoints. The dryslot will clear out any of Friday's left over convection. Steep lapse rates and strong wind fields will be more than enough to support strong updrafts and tornadoes.

Later in the day more cells should erupt along the dryline in SW MO, E OK and W AR. These storms will quickly merge into a broken squall line, but still be capable of tornadoes. The squall will blast eastward bringing the possibilty of strong tornadoes over E MO, E AR, and S IL.

Current Chase Target: Independence, KS

 

[Brian Stertz]

Update based on 12z ETA (2/22)

UPDATE: the 12z ETA shows things setting up a little bit further west in C.Kansas. The forecast model roller coaster will likely continue as the models try to sort out this bowling ball storm and ripping jet heading for the C/S Plains and Mississippi Valley.

I am still liking the corridor from Emporia to Winfield KS to Bartlesville OK eastward into SW MO as the chase target. From 6z Meso Eta...it shows decent 0-3km CAPE and good 0-6km bulk shear. With some help from the dryslot, the sunshine should allow things to brew nicely and some low topped supercells should emerge. Info at 18z Sat. is below.

http://www.wxcaster.com/CONUS_MESO-ETA_0-3KM_CAPE_60HR.gif

http://www.wxcaster.com/CONUS_MESO-ETA_BNDLYR-6KM_WINDSHEAR_60HR.gif

 

[Mike Peregrine]

GFS certainly likes to break the precip out further west. But I'd agree with Brian that the better wind environment should set up a bit to the east. This will definitely be a day to watch soundings. If a person ends up too far west there will be absolutely no hope of catching up again. At the same time, this looks to be a heavy precip system. Lots of moisture working its way into this storm. I really have faith that it can work and that the skies will clear in time for a show, but it could easily go either way. For those who are basing their forecasts off of SPC convective outlooks, keep in mind that on this storm, the hatched probablistics are likely designating the nocturnal aspect of this system. From a chaser's perspective who is interested in daytime storms, pinpointing the western-most initiation is the most important thing. Even though Kansas doesn't look appealing on the SPC map, it is that possibility for mini-supes that is drawing the attention of several on the board. For those deeper in the midwest (Illinois, etc.), even though the low is progged to move through quickly, I wouldn't get my hopes up for anything before dark. Also, I agree that climatology heavily favors the south and Gulf coast this time of year. But again, from a chasing perspective, the forecasts are concentrating on what can happen in good terrain. I think it's also a good thing to increase awareness on these types of events, whether what we 'assume' will happen actually does or not.