August 9th, 2006 severe; northern plains under the gun

[wxmann_91]

Dean, are you chasing this setup?

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For this setup:

Good news:
a) Deep layer shear is sufficient for sups
b) No thermonuclear cap; CINH is negligible; 700 and 850 mb temps will be marginal but okay, but WRF initates precip
c) Backed winds dramatically increase moisture; LCL's will finally NOT be a problem
d) MCS in morning may leave a boundary to work with in the aftn.

Bad news:
a) Low level shear is weak, tendency for cells to become outflow dominant (THIS IS HUGE)
b) MCS rolling thru morning may add to CINH.
c) NAM has trended downward on instability and SRH
d) It's still 2006.

After a quick glance at modes, here is my outlook:



FWIW, GFS progs nearly 10,000 j/kg of CAPE at OAX :

http://img215.imageshack.us/img215/1053/indexcd8.gif

[wxmann_91]

I don't know if anybody cares, but the GFS is absolutely crazy, progging over 11,000 j/kg of CAPE for Aurora, NE!! I don't think I've ever seen such high CAPE values before...

http://img214.imageshack.us/img214/3525/indexng7.gif

[dean]

they're just going crazy with that! i saw one LI in northeastern Nebraska of something like -16.7! CAP is going to be a problem though and shear definately isnt great either. if i was going out today, i would be heading over towards Mitchell, SD as they look to have good parameters, a weaker cap, and good road options.

[WindRunner]

Yeah, in the outlook SPC mentions the cap being stronger the after the MCS this morning.

And the GFS is just crazy. 12Z sounding for OAX had almost 1000 for the CAPE.

However, a 19Z sounding at Aberdeen reveals a slightly more potent environment, with strong shear and around 4000 J/kg CAPE, and LI's at -12 with good lapse rates around 8 C/km. OK, so that is a pretty good setup, but not much is popping as of yet, thanks to the cap again.

[Bunkertor]

I don't know if anybody cares, but the GFS is absolutely crazy, progging over 11,000 j/kg of CAPE for Aurora, NE!! I don't think I've ever seen such high CAPE values before...

http://img214.imageshack.us/img214/3525/indexng7.gif

11.000 CAPE ? Do you think that´s possible. That must be a mistake.

[dean]

some very nice storms out there right now, if these hold up overnight, we could have a very strong squall line later tonight.

[WindRunner]

Yeah, looks like a line trying to form up north and west of Aberdeen. Might make it a noisy night for you, dean, whether a squall line develops or not.

[dean]

If these storms continue to develop eastward in to eastern MN then it should be a fun night. I wont be seeing the storms that are out in the Dakotas tonight because they are all moving south to southeast, but if convection continues to build into northern MN then i may have a chance.