4/5/10 FCST: NE,KS,OK,IA,MO

[Mike Smith]

As discontinuous retrogression occurs the first of the week, the trough digging in from the Northwest may lead to a surprisingly potent "day before the day" setup on Monday.

The moisture from the early weekend system (April 1-2) will not be scoured out and will time have to increase during the late weekend creating the first warm frontal opportunity in the Plains this year.

Strong jet stream with digging (and possibly negatively tilted short wave) will induce rapid pressure falls in the Plains (KS-NE) that are likely to keep surface winds southerly with very strong veering to 500mb.

Good dryline opportunity for supercells in NE-KS-OK with warm front opportunity from E NE to W. IA and possibly NW MO.

If I were going to pick one day (in the Plains) to chase out of the next seven, this would be the day.

 

[Kevin Walters]

I was looking at NE and IA for possible warm front activity as well. Moisture might be an issue, although that often takes care of itself. The wind fields look good so things could get interesting.

 

[Greg McLaughlin]

If I were going to pick one day (in the Plains) to chase out of the next seven, this would be the day.

I agree Mike. The things appear right now, MON looks to have the best potential from the way I see things. I am hoping things actually pan out. It appears moisture will be much deeper as the GFS is showing 850mb Tdps aropund 15C which is pretty good. It also appears like we could have pretty good convergence along the dryline. I will be keeping my fingers crossed over the weekend.

 

[Brian Stertz]

The Euro was hinting at maybe an outbreak solution, and then it turned into a quickly progressing wave...mainly impacting areas north of I-70. Strong shear...adequate
LL moisture should make either Monday 4/5 or Tuesday 4/6 into the big severe wx days. Convergence may be somewhat suspect south of I-70 with veered winds. Things will have to be watched. If the system could slow down some, this could make Tue. extremely interesting for chasers....even as-is...things could be quite good one or both days. Think Mother Nature's alarm clock is about to go off.

 

[Scott Hammel]

I've actually ditched chasing Thurs/Fri in favor of this day. This looks to be quite an interesting setup that should definitely yield supercells. The 12z GFS shows a nice ribbon of CAPE from S KS all the way up to NE with values in the 1000-1500 range. Good veering winds and sfc dews around 60ish through most of KS. And there isn't a Ft. Knox-like CAP to break like tomorrow! If things hold up over the weekend, I will be out for this one...

 

[Chris Wilburn]

I agree Mike. The things appear right now, MON looks to have the best potential from the way I see things. I am hoping things actually pan out. It appears moisture will be much deeper as the GFS is showing 850mb Tdps aropund 15C which is pretty good. It also appears like we could have pretty good convergence along the dryline. I will be keeping my fingers crossed over the weekend.

I agree as well. This day has looked good for the last few runs or so. Directional shear is very nice compared to what this Friday has in store which is good. Nice dryline from NE to TX. Models now show some CAP in OK, but less in KS. Hard to tell these things 5 days out so just pointing that out as of now. Like you mentioned td's at 850mb are near 15C which is a plus for sure. Everything looks good as it stands now. Plenty of moisture and a tongue of over 2,000 CAPE from in KS just west of I35. Hopefully this pans out as it looks really nice right now!

 

[Michael Riedl]

This is looking as a great day so far. The 18Z GFS (off hour I know) paints an area of 2000+ CAPE through Central OK into SC KS, where the CAPE appears to be the highest.
The 18Z GFS shows td's at the surface are around 65 through most of OK and Southern Kansas. There is a small cap but not too strong and definitely not unbreakable. Good enough to keep the Crapvection down.

If I were picking a target this early I would go with Enid, Oklahoma.

 

[Jeff Duda]

I have also been watching this day since yesterday. Great dynamics. I just hope the thermodynamics work out. Otherwise it will be a wasted setup. Also the GFS has been bouncing around on the timing/location of the surface features. I believe the 00Z run from two days ago suggested this would be a Tuesday event, then progressive runs bumped it up to 06Z Tuesday as the best positioning for action around IA/NE, and now has forwarded it to good timing on Monday. Will have to wait and see how the NAM handles this as it works into the 84-h window.

 

[Mike Hollingshead]

I'm feeling more comfortable at least with Monday's op and setup unfolding close to how the 0z GFS now has it. Doesn't mean I figure it has the handle on the 6th yet though!

The front/moisture issue seems to have vanished, stalling it just into the gulf and then letting it return north a lot sooner than it had been showing early on. Last several runs are fine with that and moisture return.

It now has the sfc low forming way west and slower like ECMWF was thinking as well as a few Canadian runs. The warm front looks like a pretty solid play now right where the dl arc and hot air will intersect it. Right now that is somewhere out around sc NE/nc KS border. Fine by me if that is what ends up happening for the day before the day. Hoping GFS is still out to lunch on how fast it slams the through through on the 6th. But regardless, doesn't seem now all that will have much effect on the 5th.

Near/west of CNK forecast sounding and hodo off the GFS is closest I could get it to pull from(dropper jumps to set spots evidently).

Given pretty flat mid-level flow and lifting front. Mmmmmmm just a hair.

 

[Jim Bishop]

Like everyone else, I'm excited seeing what the GFS shows for Monday. But the European and Canadian models are much slower to eject the shortwave. So it may be that Monday is a decent setup, but with a strong cap and no upper support, and Tuesday ends up being the big day. We'll see...but one day early next week should be big.

 

[Mike Hollingshead]

Yeah, wow are the Canadian and ECMWF really liking that much slower idea, even slower than they have been and they have been the slow ones. GFS is going to have a lot of catching up to do at this rate. They do now put the question mark fully on Monday. Right after I got all comfortable with it happening to the west. Something tells me GFS won't catch on today yet either.

Edit: As 12z GFS pretty much holds firm. Sigh. Come together already damn it. Though heck, it's slowing Tuesday down considerably! "shocker" there. Hell looks a bit like that wildly intense ECMWF run the other night. Maybe we are finally going to get somewhere. I only hope we don't get one "too late" day followed by a day to the east and that is it.

 

[Brian Stertz]

Seems to me that the slower trend and consistency of the Euro is to be believed. This will put the beefier supercell/tornado action for Tue 4/6...and maybe a day 2 event on Wed. 4/7. May be dealing with capping on Monday but will keep an eye and continue to monitor....warm sector looks like it could be plenty energetic.

 

[Adam Penney]

Seems to me that the slower trend and consistency of the Euro is to be believed. This will put the beefier supercell/tornado action for Tue 4/6...and maybe a day 2 event on Wed. 4/7. May be dealing with capping on Monday but will keep an eye and continue to monitor....warm sector looks like it could be plenty energetic.

I agree. The 12Z GFS has 700mb temps running near 10C and poking into Oklahoma at 0Z Tuesday. From the overall perspective, the off-hour 18Z GFS has trended more towards the slower solutions recently displayed by the Canadian and ECMWF models, showing the bulk of the forcing hanging back until Tuesday(4/6).

With the lack of forcing on Monday, the CAP may be tough to break. However, in contrast to what we have been seeing during recent setups, are the CAPE values continuing to be progged AOA 2,000-2,500 j/kg, and dewpoints look to be solidly into the low to mid 60's in the target region, so the chance at breaking the CAP on this day, may be doable.

Agree that Tuesday may in fact end up being the "day' as the slowing trend has continued, now displayed by the 18Z GFS.

 

[Derek Weston]

GFS continues with its one and done Monday play. As of this 0z... would be a huge day in So. Kansas if it came to fruition. (hopefully no big cap issues... we've got some impressive parameters)

Do remember the GFS winning out at times over ECMWF... be interesting to see how this all unfolds.

 

[David Wolfson]

To my eye the models seem to be settling on a pretty significant tornado possibility coming out of south central KS for late afternoon and evening. 00Z yesterday a Hutchenson target was also showing and the timing is starting to lock in. The really stout dryline and shortwave screaming in (by +24h all the dynamics are showing their passports at the Canadian border!) should be more than enough to break the cap and the 2000+J/kg CAPE takes it from there. Plenty of shear... just a lot to love.... Storm motion from 240 at 40+kts or so should add some excitement for those doing their first chase-day shakeout.

As the above comment about 00Z on the 7th suggests, I won't be the one to start a FCST thread for the 6th, although I might if I lived in eastern MN or WI.