1/27/08 FCST: OK, KS, AR, TX, MO, IA, IL

[Mike Hollingshead]

Perhaps a bit on the early side of things, but it's within the 7 day range. ECMWF the last two runs has indicated a strong system coming out this Sunday, deepening to a 978sfc low by 12z Monday. 18z GFS is now onboard with a very dynamic system Sunday in the central and eastern plains.

A look at the sfc obs show upper 60 dews along the coast at this time. A cold front should arrive later in the week giving them a fair smack south. That is prog'd to turn around pretty quickly though. A strong low level jet and deepening sfc low should return that moisture north through the plains, for maybe an interesting day Sunday.

Something to keep an eye on. The 18z gfs is rather wild.

http://weather.cod.edu/forecast/AVN/OFFAVN/avn_usUS_250_spd_126.gif Very strong upper jet.

http://weather.cod.edu/forecast/AVN/OFFAVN/avn_usUS_500_spd_126.gif
Very strong mid-level jet, lol....a watch them fly by day if there are storms.

http://weather.cod.edu/forecast/AVN/OFFAVN/avn_usUS_850_thetae_126.gif
Strong, but veered low level jet. May not be too big of an issue if there remains deeper moisture just below that.

http://weather.cod.edu/forecast/AVN/OFFAVN/avn_usUS_2_temp_126.gif
Strong surface low(ecmwf also indicating this) so hopefully there can be some more southerly and less backed sfc and lower level winds.

Yeah it'll change several times between now and then, but it's nice to see some sort of agreement already(and most importantly that the better ecmwf model likes this whole idea of a strong system Sunday).

 

[Chris Wilburn]

It sure is nice to at least see something on the horizon, esp. warmer temperatures. The models do bring in a strong system with a nice surface low and strong upper level support. Moisture looks good too with mid to upper 50 dews in SE KS/ Eastern OK. The veered 850mb flow doesn't look good, but if we can get backed surface winds that will help. I agree Mike that things will change several times before then, but at least it gives us a reason to look at the models. I would even go for a nice squall nice/ MCS type event with some good lightning. As usual only time will tell.

 

[Bill Tabor]

GFS shows dews fairly low except down in Tx and some extending into southern MO, AR, eastern OK, LA. Some decent wind fields could perhaps generate something worthy of monitoring though it's very iffy at the moment.

http://www.rap.ucar.edu/weather/model/displayMod.php?var=gfs_sfc_dewp&hours=hr120hr132

This as I consider turning off Threatnet for the off season.

 

[Mike Hollingshead]

GFS shows dews fairly low except down in Tx and some extending into southern MO, AR, eastern OK, LA. Some decent wind fields could perhaps generate something worthy of monitoring though it's very iffy at the moment.

http://www.rap.ucar.edu/weather/model/displayMod.php?var=gfs_sfc_dewp&hours=hr120hr132

This as I consider turning off Threatnet for the off season.

Well, the 12z gfs looks like crap and really doesn't look much like the 0z and 12z ecmwf or the 18z gfs. I have no clue how off hour runs catch onto things and look so much different, but I've seen it do that often, only to be followed up by the next normal run with that change in place. We'll see on tonight's run if that happens. Either way, ecmwf more supportive than the 12z gfs.

 

[Mike Hollingshead]

And there it goes, 0z gfs took the trend of the 18z run, though a hair slower on Sunday. Dews have a little work to do, but they are close enough to be very interesting if things continue.

Edit: Now looks like the 12z gfs and 0z ecmwf have both slowed it down even more. So it comes out more overnight Sunday. Hopefully this slowing will continue and have it come out Monday, with more time for dews to recover.

Edit: Looks like the slowing trend is continuing. Any way to change the date for this thread? Looks like Monday will be the day.

 

[Brian Emfinger]

Well the 0z GFS at hours 120-126 (0z Tue-6z Tue) is bringing up 60 deg dewpoints into SE OK and SW AR with cape values around 750 from Dallas through much of Eastern Oklahoma and even a sliver northward into central MO. Every pressure level is out of the SW but there is plenty of speed shear. Thunderstorms look like a good bet and I imagine we will see some severe thunderstorms with strong winds (60kts at 850) being the likely main severe threat. The 6z GFS is out now and the 114 hour (0z) is showing much more southerly winds than the 0z GFS...if that trend can continue then I think we could have a marginal chase opp for SE and E Central OK.

 

[Derek Weston]

Looks like linear fun to me -- that's some rather unidirectional sheer.


Although last setup in the midwest that brought us some fun didn't look too good in the sheer department... (though, if I recall correctly, still better than this)

 

[Dustin Wilcox]

Edit: Looks like the slowing trend is continuing. Any way to change the date for this thread? Looks like Monday will be the day.

It continued for a couple of runs until this mornings 12Z, much faster and pretty much puts a fork in any hope for decent convection, the surface low (972 FWIW) previous forecast to be over SD MON now shoots of to the NE, maybe still keeps some hope for areas just East of the plains, if you feel like chasing rockets through the hills, but even that has diminished some. If only we could get a system like this in 2 months!!

 

[Mike Hollingshead]

You know it really sucks what has happened to the return flow prog'd for this system. It was kicking in fairly early and showing decent dews into KS. Now that cold front and high slips into the gulf late and simply kills the dews. Mid 60 dews in the central gulf right now, with 70 in the west central gulf. It only sucks because it is indeed slowing down for Monday. 0z ECMWF has the sfc low in ne SD Monday evening now. Hell 6z nam has the dryline in central KS at 6pm Monday....what bit of dews there are. Even has the strong little vortmax in sw KS at 18z now, moving over the dl during the afternoon. Damn the dews. I wonder how little dews one can get by on this time of year, even with it not being cold core. Wonder if 50 could be interesting. I'm trying too hard with this one, I know.

 

[Michael O'Keeffe]

I am very interested in Central Kansas Monday afternoon and evening! The 12z NAM is showing we will have sufficent moisture and temps, with very good 250mb winds, 500mb winds, and decent 850mb winds. CAPE will be around 500-600 j/kg which is good enough for this time of the year. I really like the enhanced vorticity over I135 that is right near the dryline/cold front intersection. If something can initiate right in that area I wouldn't be surprised to see a tornado or two with all of those factors in place and the great shear. It is something we really need to keep an eye on.