9/14/04 FCST: Plains/Mid west

[Andrea Griffa]

Maybe it's still too early but GFS forecast doesn't change from some run....
A good low pressure at the ground and a good long wave through.
The area will be Kansas,Nebraska,Iowa...I'm anxious to see waht it's gonna be. It looks like a good chasing day. What do you think about?

 

[Glen Romine]

This date may still come to fruition - but the likelihood remains rather sketchy still. Last few runs of the ETA have continued to advertise favorable shear profiles during the evening hours over western IA - along with reasonable moisture. However, the moisture is still suspect - as the operaitonal models agree that a surface ridge will remain in place along the Gulf Coast - effectively preventing good moisture return in advance of this system. The ETA may be too far west with its placement of Ivan - which enhances the ridge strength, and while the GFS is further east, the forecast height falls in TX appear inadequate to funnel Gulf moisture northward. Looking at the precipitable water forecast from both models - the disconnect between the moisture pool over the upper MO valley from that further south suggests moisture pooling will likely be key to any tornadic threat that may emerge. At this point - still looks like large hail will be the primary threat. I see SPC has a slight risk outlook for this area as well.

Glen

 

[Mike Hollingshead]

http://www.rap.ucar.edu/weather/model/disp...r48hr60hr24hr30

http://weather.uwyo.edu/cgi-bin/sounding?r...1212&STNM=72261

Well I'm still really green at this forecasting thing and it probably shows every time I decide to open my mouth on it at all. I will also be wishcasting a good deal again as it's quite local. So take this for what it's worth and please inform me when I am just way too far out on that limb. I agree the moisture return looked really scarce on this. I only glanced a day or so ago and it kept ne winds over the gulf through the period...or close to. That Del Rio sounding looks fairly deep to me and that region will have some return fetch to it and a sublte supply of 'real gulf moisture'...or as real as it gets in 2-3 days.

http://www.rap.ucar.edu/weather/model/disp...r42hr48hr60hr30

Yep, I agree.....we need some pooling wonders to help this out. Shear is looking a-ok to me. On a 1-10 hope scale my hopes are around an 8. Early pick of Columbus NE.

Mike

 

[Mike Hollingshead]

http://www.wxcaster.com/modelskewt.php3?mo...&STATIONID=kslb

For northwest Iowa per 18z eta. Ummmm.

 

[Glen Romine]

Still looks like there is some potential for tomorrow in the Mo. River valley area. Moisture is making some progress northward over the surface boundary, and shear profiles look ok for tomorrow (although not much veering at midlevels). Cloud bases probably higher than those forecast by ETA, but if the cap can hold cells from developing too far south out of the better deep layer shear, I think it oculd pull itself together. Mike, you might want to charge up the camera tonight, just in case!

 

[Tony Laubach]

Thought I'd chime in from Colorado...

Not too shabby for early/mid September here in Colorado.. yet another good post-frontal situation shaping up across the High Plains. SPC has expanded the 2% TORNADO RISK from their earlier outlooks to include areas up to the front range as opposed to the small bubble over far northeast Colorado as stated earlier.

My chasing may be severely limited due to being on campus til 4:00p (exam last class) and the fact that my car is in the shop undergoing replacement of a flex plate. However, something locally could happen (wind/hail) that at least could warrent me chasing it to the end of my apartment complex.

In any case, a bummer of my personal situation as I normally have Tuesday evenings off.. figured if I finished my exam early, I could head east from downtown and hopefully make it in time. No go, today...

Hope someone gets this late season chance around here.. fall's gotta be sneakin' in here soon!

 

[Verne Carlson]

SPC just increased the tornado risk to 5% for NE Colorado. From my house here in the foothills I can see a lot of moisture out on the plains and no clouds to keep temperatures down. Seriously considering heading up I-76 if something pops!

 

[Tony Laubach]

Just called the shop to check on my car; going to be at least tomorrow before its ready to roll again; thus officially killing off any chance for a chase beyond my parking lot! Saw Verne's post regarding SPC's 5% and wanted to cry.. ah well.. can't get 'em all!

 

[Tim Stoecklein]

I was thinking somewhere in between Grand Island and Lincoln for initiation, but I don't know if that area will recover after this morning's showers. Of course, what do I know...

I'd go south and east of Lincoln to South of Omaha.

Tim

 

[mikegeukes]

CNTRL/ERN NEB INTO WRN/CNTRL IA
SURFACED-BASED TSTM DEVELOPMENT IS EXPECTED TO BECOME MORE LIKELY IN THE NEXT 1 TO 2 HOURS AND A WW MAY BE REQUIRED.

http://www.spc.noaa.gov/products/md/md2204.html

Mike

 

[Mike Hollingshead]

Interesting you can see that boundary clearly on Omaha's radar running ne-sw right over Columbus embedded in that garbage. The best dews/instability seems to only go west a couple counties into NE and then well east of there. I'm not sure I'd want to go very far west into NE. Fairly stout south sfc winds over much of KS pumping the juice northward into that boundary. 850 jet also nosing ne across c KS pointing right at Omaha. I suppose the Columbus area works for me right now. Going to sit here incase something sfc based does pop in IA on that boundary. Not very thrilled with type of setup though. Look outside and see garbage everywhere. Oh well we shall see.

 

[Mike Hollingshead]

http://www.spc.ncep.noaa.gov/exper/mesoana...is/s2/xover.gif

Going to be a pretty nice turning profile west of Omaha here in a bit. Already is actualy, but evidently the 850 is wanting to back more to the west now.


http://kamala.cod.edu/spc/watches.gif

Severe box out for NE/IA now.

 

[Glen Romine]

Tornado warning from KUNR.

"AT 144 PM MDT...SPOTTERS REPORTED A TORNADO JUST NORTH OF THE
BLACK THUNDER MINE. THIS TORNADO WILL MOVE NORTHEAST AT 30 MPH."

There are a couple of nice looking cells out that way. Some healthier looking convection starting to go up WNW of [edit]DSM[/edit] as well.

Glen

 

[mikegeukes]

2 Severe Thunderstorm Watches have been issued:

CENTRAL AND WESTERN IOWA EASTERN NEBRASKA
http://www.spc.noaa.gov/products/watch/ww0819.html

NORTHEAST COLORADO, EXTREME NORTHWEST KANSAS
SOUTHWEST NEBRASKA AND FAR SOUTHEAST WYOMING
http://www.spc.noaa.gov/products/watch/ww0820.html

Mike

 

[Tony Laubach]

***New thread started for ongoing convection***

SPC has issued an MD for Northeast Colorado and adjacent areas in Wyoming, Kansas, and Nebraska. Main concern is hail and high winds, but MD mentions a possible tornado. Would imagine a SEVERE watch to go up, however, wouldn't be surprised to see it be a TORNADO watch.

Things are looking pretty decent for storms to get going in the foothills; as they move east, they'll encounter higher amounts of CAPE and shear, so would imagine the seeds being dropped over the mountains for storms to fire and move into the better enviornment. Wouldn't be surprised to see severe to tornatic storms going up along I-76, moving eastward out of thr urban corridor.

One storm firing east of Denver now, more in the NOW thread. Other storms should begin to kick off within the next hour or two as the atmosphere continues to destablize. Temps in the upper 70s with dewpoints in the 50s make this a pretty good mid-summer setup in the middle days of September.

***EDIT*** While typing this, SEVERE WATCH went up for NE Colorado and areas.. guess the tornado watch was a wishful thought! :wink: