Dec 18, 2003
Norman, OK
Classic cold core setup for this afternoon in SW and C Oklahoma. The center of a very cold 500 mb trough (temps around -25 C) will pass over western and central Oklahoma this afternoon. A pseudo warm front will setup between Oklahoma City and Ardmore this afternoon, which will enhance low-level shear and lower LCL heights a bit. Deep-layer shear will also be strong, which empirically (according to Jon Davies) supports the possiblity of somewhat longer-lived tornadoes in any low-topped supercells that form.

Also, Jon Davies NSTP composite index is maximized by the RUC from SW OK at 21Z to C OK at 00Z. With insolation likely beginning in earnest shortly, low-level lapse rates will also be maximized which will yield a very favorable environment for the tilting and stretching of the low-level vorticity (which should be in abundance today).

Gabe, this is erie as to how similar this setup is to Nov. 27 in se ks. only here the storms wont be moving 70knts and they will be in c ok. It could be fun... :D

Latest OA shows strong, veering winds in the areas of clearing skies, and the high helicity wind profiles are remaining in the regions with more backed winds under overcast skies. The storms with the best chance of large hail and perhaps an isolated tornado will be those which are closest to the frontal occlusion where the higher helicity will be present.

That's my take - i'm more skeptical about the magnitude of this event, but i'll be watching because these setups always seem to be interesting. :)