10/12/08 FCST: TX/OK/KS/NE

[Michael O'Keeffe]

The 12z GFS is now in nearly full agreement with the ECMWF showing a mean trough moving into the Plains. As of right now both Saturday and Sunday could hold potential, but Sunday looks to be the big day. Moisture, temps, and shear look very nice with this setup. As of right now it looks to be a nice Panhandle day possibly. Many more runs to go, but it is nice to see the models agreeing.

Just because I didn't really address it write above I would like to make it clear this thread is for Sunday. I can make a seperate thread for Saturday if wanted.

 

[Jeff Passner]

At first glance, I don't see much happening Saturday afternoon. There seems to a respectable cap and no significant lift. I can see some storms Saturday night with a strong low-level jet and strong moisture advection.

Sunday does look a very exciting day, although the dynamics remains well west of the area with the latest model runs. A dry line should still form and given the forecasted shear profiles anything that does form could rotate. I still have concerns of warm temps aloft (especially 500 hPa), or a cap that holds until 0000 UTC.

The models have been trending west with this upper low so who knows, this whole thing could shift back many hours if that trend continues.

 

[Adam Penney]

Well once again, the dynamics are certainly there for a big severe weather day, but my big concern at this point is instability. CAPE is progged to be at best around 1200-1500 J/Kg. I will admit, this is really the first time I have paid attention to the "second season", so maybe this time of year, with strong dynamics, 1500 J/Kg may be enough to get the job done. However, call me skeptical at this point. Certainly, SW KS to the OK and TX panhandles look like the favored areas at this point.

 

[Fred Gossage]

The main thing that has me skeptical of the severe weather threat with this system, as mentioned above, is the warm mid-levels. 500-mb temps are progged to be in the -4 to -9 deg C range over almost the entire warm sector through the weekend and Monday. Despite rich boundary layer moisture returning, and decent prospects for insolation in the warm sector, this kills any significant potential for instability. Then, also as mentioned above, the have the problem with the dynamics remaining behind the cold front.... I have a feeling this storm system will be more known for its snowfall totals from Colorado into North Dakota... than a significant severe weather maker.

 

[Andrew Stoller]

Sunday looks like a massive cold front squall line as the surface low ends up way to the north in the Dakotas. But Saturday is still looking a bit interesting as far as discrete cells go. Sub 1000 mb surface low sets up in southcentral CO with nicely backed winds through 700 mb. Dew points in the mid 50s. But instability is just not there with warm mid level temps. CAPE progged to be 750 J/KG at best.

 

[Brian Emfinger]

I don't have a lot of time these days to look over things in depth and I usually just skim through the gfs and wrf. Well, I just noticed the NHC has Hurricane Norbert racing NE into E New Mexico by 11pm Sun. The gfs still shows it out in the Pacific at this time. The NHC doesn't believe any part of the GFS and I'll side with them. How will this tropical system affect this setup?

 

[Andrew Stoller]

As it stands right now, I'd say southwestern KS looks pretty darn good for Sat! 12Z Nam is showing up to 1,500 J/KG CAPE with 60 degree dewpoints directly east/southeast of a 997 mb surface low in south central CO. Winds are nicely backed through 700 mb by 00z Sun, then veer out of the southwest at 500mb to 60 knots, creating up to a 500+ m2s2 storm relative helicity.

Unfortunetally there is still a little CINH and warm mid level temps to overcome, but the Nam does break out lots of precip around Scott City, KS.

I'm keeping my fingers crossed!