9/29/07 FCST: SD / NE / CO / KS

[Brandon Lawson]

I realize things are looking bleak for any kind of sugar coated weather on Saturday and the SPC even mentions downgrading their 4-8 outlook, but the fact that somewhere in the plains could see severe weather on Saturday(the best possible day of the week for me to chase during school) has me doing my usual wish forecasting. And heck, why not? I'm chase starved.

Right now I'm wishing for a northern KS chase with better than forecasted dewpoints. Discuss.

 

[David Drummond]

Please start a thread in the Target Area for discussions this close. Events within 7 days need to be in the Target Area formats rather than Weather and Chasing. Thanks.

 

[Dustin Wilcox]

Timing is big, latest trends have been to slow the wave down a tad bringing the core of the energy across the plains after dark. Moisture seems to be ample according to model solutions, though I think they may be a little suspect given moisture conditions across the gulf states, regardless given strength of wave and forecast strong wind shear, I'm remaining optimistic, and hoping for deep cyclongenesis, after all what could be better then a Fall Saturday chase during an non-televised husker game, it would be awesome to get a chase in while listening to the game on the radio with combines harvesting in the foreground and a nice little supercell in the background.

 

[Brandon Lawson]

Please start a thread in the Target Area for discussions this close. Events within 7 days need to be in the Target Area formats rather than Weather and Chasing. Thanks.

I apologize for that. I didn't think the conditions warranted a real forecast thread and I just decided to post something more for general discussion. That's why I was talking about wishcasting. And now the models look even worse than before with regard to the moisture.

Why did we have high dewpoints all during the month of september only to have them wiped out when we finally get a trough?

 

[Jeff Snyder]

Just as an FYI -- I moved this thread from W&C into Target Area...

I agree that there is potential for Saturday, though uncertainty remains very high. Tonight's GFS run, predictably, hangs the trough back a little longer (at least compared to a few previous runs), which seems to put the "sweet spot" out of phase by about 12 hours for my personal preference (overnight Saturday into Sunday morning). As it is now, the best risk Saturday may be from northwestern KS into NE and SD, pushing into the Upper / Mid MS River Valley and western Great Lakes area Sunday (but that'll be another thread). As noted, moisture availability will be highly questionable, with model forecasts indicating poor Tds for much in the way of a significant event. I'm not entirely sure where the >60F Tds go between now and Saturday, since short-term model guidance (e.g. NAM) indicates >60F tds in OK through Friday evening, before those Tds drop Saturday on stiff southerly winds. I do think that TD13 in the western GoM is making a mess out of our return flow situation, and we may end up with recirculated continental air on the south side of the large surface high that'll be centered over the Great Lakes Friday and Saturday. Looking at 850mb heights and Tds, it appears that 850mb-level ridging noses a little too far into eastern and central TX for my liking, and some subsidence associated with that large high/ridge may be drying out the low-levels (and some of that drier air may mix down in strong low-level flow Saturday).

Shear profiles appear to be supportive of supercells Saturday, mainly N of I70. With marginal low-level moisture, however, instability may well be a limiting "ingredient".

The latest ECMWF that I've looked at (12z/26) showed the strong shortwave trough farther south and a little slower than the latest GFS. If that ECMWF verifies, I'll be quite excited about the eastern Plains area Sunday (though, again, that'll be a different thread).

 

[Mike Hollingshead]

Huron SD 0z Sun NAM Forecast Sounding

I'd say if those prog'd mid-60 dews get into the Dakotas and the nam is right, the crap may hit the fan from Canada to KS. I mean that's quite the shear profile. I just hope it picks a day and does it, and doesn't do something closer to what the gfs is showing now. GFS still a little slower than the nam, but both sure zing it on out and hose Sunday.

Needless to say I'm cheering for the NAM now, but am really scared it's just too fast and like seems the case more often, the GFS will have the better handle on this. Even the GFS run leaves some hope, but not like the current NAM...for Saturday.

250mb

850mb

SFC TDs

0-1km EHI

 

[Scott Weberpal]

Could be a big event north of I-70, however, I have little faith for daytime convection. Cap will be extremely stout, and even with mentioned height falls in SPC outlook, convection by 7 pm is an outside shot. I'd be chasing tomorrow if I felt better about the prospects for initiation before dark.

 

[Ryan Pfannkuch]

Can't say I'm terribly excited about surface Td values in the mid 50s to MAYBE low 60s...but the strength of the deep and low level shear has talked me into it...and I'm gonna be trekking west this afternoon for better or worse.

I was debating back and forth about what portion of the SLGT risk area to target...and I've finally settled on the southern portion...generally along the NE/KS border in a triangle between McCook...Imperial...and Goodland.

My Saturday expectations have been tempered a bit over the past few days...especially after Friday ended up being a sneaky "day before the day" sort of setup (congrats on catching some nice storms Mike U.)...but if something can remain discrete for awhile you never know.

 

[Andrew Stoller]

Think I'll head out..............it's Fall, it's Saturday................could be some isolated Supercells. Heck yea!!!

The RUC really seems to initiate the convection around Burlington; maybe even a bit further south towards Cheyenne Wells, CO. As of now, I have my sights set on about Seibert, CO. Good road options north/south, and of course, east on I-70.

 

[Mike Umscheid]

I was debating back and forth about what portion of the SLGT risk area to target...and I've finally settled on the southern portion...generally along the NE/KS border in a triangle between McCook...Imperial...and Goodland.

That's exactly my target, and I await here in Benkleman. Temps, despite the cirrostratus are in the mid-upper 80s. Something should pop real soon with that nice forcing coming out of the Rockies. I am expecting to see a decent severe storm with near 60 dewpoints just east of the dryline...tornado threat appears limited... if only the dews were in the 63-64 range. The RUC was overdoing the surface dewpoints unfortunately. We'll see what happens..

 

[Brandon Ivey]

I chose to make the long drive to play the southern target as well. I am currently sitting in Goodland, KS. Looks like storms are trying to organize in Eastern Colorado. I agree with the ruc overdoing the dew points by 3-5 degrees. I just hope its indications of the SFC and 850mb backing somewhat towards 0Z hold true. Surface winds here are dominately out of the SSW with some gust out of the SSE. We will see what happens. May be a long trip with little rewards. I should have chased yesterday rather staying in Wichita. As always, nice images Mike U!

 

[Mike Hollingshead]

Well, that little storm that just went over North Platte was wound the hell up as it did so. Hopefully this next one can be a little better rooted. Seeing what that little one just did...

Wow, just looked at a new sfc plot. Surprised to see things backing that much.

So much for that thought. Looks to get messy soon. Sucks seeing all the tops going up down to the sw and know they probably won't have time alone.