11/5/08 FCST: IA/MO/AR/E. KS

[Scott Weberpal]

Current GFS indicates a potential chase day next Wednesday, especially in MO through S. IA. A deep, vigorous trof is progged to eject out of the four corners region into the upper midwest with an attendant deep surface low. Moisture will be a major question mark (when isn't it this time of year?), but cold temps aloft should help offset the moisture issue.

At this point, southwest to southcentral Iowa into W. MO appears to be the favored region, but I'm sure the models will have major mood swings before next Wednesday arrives.

Something to keep an eye on.

EDIT: I completely overlooked the E. NE/SE SD cold-core potential during my original post. Low 50 Td's forecast juxtaposed with -20 to -25 H5 temps, and in the immediate vicinity of the deep sfc low. I may actually favor this area over the typical warm sector play if it pans out.

 

[Mike Hollingshead]

I think of two days when looking at this one. November 12, 2005... not so great moisture....time of year....mid-level low to some degree, and location of things. That day the sfc low also played out with tors. I think the mid-levels were a bit less backed than the gfs prog's at the moment. But it is something to watch.

The day I could see it turning out more like is the day Van Dewald got that dusty tor in nw IA. I can't remember the date, but I know you chased it too Scott. Surface low position is rather close to both those days if I recall.

Hopefully the ECMWF will slow down from where the 0z run had things, as it's over by the 5th. Unless you like sw WI, lol. If dews could be there by the 4th I'd even take a two day'r.....but getting them worth much by the 5th might be a challenge. Heck a slower mix with the ECMWF would be great, slow it down, but be more open than the GFS shows the low.

 

[Chad Cowan]

SPC is really bullish with the new 4-8 day outlook. The kinematics are definitely in place, but am I the only one that doesn't see enough moisture there for an "outbreak"?

 

[Brandon Ivey]

Wednesday does look like a potential cold core event looking at the latest GFS run. Right now it looks like SE Nebraska and Eastern Kansas would be the best location to chase in. I-80 down to I-70. The target location is sure to change with future runs, but this system does look interesting. Going back to standard time tonight does not help. It will make that 2-3 hour window of opportunity occur an earlier in the day. Not good for those of us working. I would expect the 2pm-5pm timeframe to become active if this scenario plays out and I will be taking off early from work if it does!

 

[Michael O'Keeffe]

I noticed that as well, but the 12z GFS looks a lot different. The GFS is justing killing me showing a cold core setup in Nebraska one moment the next it looks like a weak warm sector event. I will likely wait for the ETA tomorrow before really start forecasting for this setup because who knows what's going to happen.

However it really could be interesting if we could get some cold core or even some decent CAPE in the warm sector.

As of the 12z GFS I'd look to SW Missouri as it always seems to perform well in these types of setups. Jan 7?

 

[Mike Hollingshead]

Apparently the 12z runs are the "crap runs" and 0z runs are the "nice" ones....on the GFS. Night it looks good, morning it looks bad. If you want to see where the NAM is, just compare it with last night's 96hr 500mb run on the GFS and its/NAM's 12z 84hr 500mb run. The current 84hr run of this morning's NAM much more closely matches how the GFS was handling it last night....so that is a good sign. And heck even the 12z GFS I could see some hope in IA and a likely chase day for sure.

 

[Scott Weberpal]

SPC is really bullish with the new 4-8 day outlook. The kinematics are definitely in place, but am I the only one that doesn't see enough moisture there for an "outbreak"?

It wont take a ton of moisture for a good coldcore event. Even low 50 Td's will be ample under such cold temps aloft. Tornadoes in the warm sector may be more difficult to come by north of the KS/OK border into AR.

 

[Mike Hollingshead]

As for moisture and November, this might be of some use. Thanks for the link Dick.

http://w1.spc.woc.noaa.gov/exper/ma_archive/

Put in November 12, 2005. T/TD/Wind 23z and Past 6 hours. Then look at central IA where big tornadoes occurred late afternoon.

 

[Andrew Stoller]

This system though doesn't look to have nearly the kinematic wind field of the Iowa set up 3 years ago. Look at how backed the surface winds were then compared to how they are projected for this setup. This setup looks quite cold front/squall linish as of now. Although with 5 days out, the system might not even be there by Wed!

 

[Dustin Wilcox]

I have about as much faith in this being a legit chase day as I do the Huskers upsetting the Sooners tonight. 12Z was a sour trend, and that was followed up by the always trusty 18Z which looks just as poor. I'm putting on my rally hat and hoping the thing slows down and that sfc low doesn't kick out so quick, if anything sub 997 is sitting over NE/IA area backing the winds under that upper level energy, I'll be happy. I'd have a hard time drawing up a better week than the skers upsetting the sooners, followed up by a November tornado; though currently both scenarios seem quite unlikely...

 

[Scott Weberpal]

This system though doesn't look to have nearly the kinematic wind field of the Iowa set up 3 years ago. Look at how backed the surface winds were then compared to how they are projected for this setup. This setup looks quite cold front/squall linish as of now. Although with 5 days out, the system might not even be there by Wed!

Last nights run had the sfc winds significantly more backed as did the run the night before. As mentioned, the 12z runs have looked terrible while the 00z runs have looked great. If last nights run comes to fruition, it should be a significant event; if it ends up more like this mornings run, expect a washout.

 

[Andrew Stoller]

Last nights run had the sfc winds significantly more backed as did the run the night before. As mentioned, the 12z runs have looked terrible while the 00z runs have looked great. If last nights run comes to fruition, it should be a significant event; if it ends up more like this mornings run, expect a washout.

Ahhhhhhhh, makes sense. I hadn't even looked at models or the SPC for the last 3 weeks until this afternoon.

 

[Scott Weberpal]

Yeah, they've been bouncing around. 2 nights ago it had a 984mb low centered over Sioux Falls with ape**** kinematics to boot. Obviously this mornings run leaves a lot to be desired. I'm placing low confidence in all the GFS runs at this point, and may have to wait until Tuesday night to make a final decision. Good news is I can easily get out of class/work Wednesday and if need be reschedule my Thurs. morning exam. It would be nice to get out one more time this season, but I'm not holding my breath at this point.

Good news is there will be convection, bad news is cold air for Wisconsin after the low passes.

 

[Scott Weberpal]

Of course the 00z GFS looks good again. Backed SFC flow east of the low and a nice broad warm sector covering most of Iowa. Coldcore looks good in NE, but I'd rather play Iowa if it appears the warm sector will pan out.

I guess I'm in wait-and-see mode now. No point in picking apart each and every GFS run when I probably won't make a decision until Tuesday night anyway.

 

[Michael O'Keeffe]

Wow I agree the GFS does look good on tonight's 00z! The 6z WRF and GFS this morning though both continue to look good which means maybe the 12z GFS may continue to look good as it is showing 60F dews all the way to the KC metro area! The 6z WRF only shows to 18z Wed, but has 1000+j/kg of cape over C KS by that time as it shows dews projected to be in the 60s at that time all the way north to the KS/NE border and a broad area stretching from C KS into W MO. This setup is really starting to become a nice looking event. Now the question is, do you chase the cold core, or do you chase the dryline?