2011-06-04 FCST: MO/IL/IN/OH

[James Gustina]

Focusing on the OH/IN part of this:

Pretty marginal setup for this weekend. Low swinging down from the Dakotas into the Great Lakes with a warm front draping northwest to southeast from Michigan through Ohio. Cold front bringing up the rear extending from Illinois back into Kansas. Pretty nice moisture spread across Ohio and Indiana with dewpoints forecasted to be up into the 70s. Back through Illinois and Missouri the NAM has the dewpoint in the 60s. Pretty nice instability overspreading western Ohio/eastern Indiana down through Kentucky and Tennessee with SBCAPE being put around 4000 j/kg. Little bit lower across northern Illinois and Missouri at around 3000 j/kg. The two biggest issues I have with this setup are the winds at the surface and the lack of directional shear. The winds at the surface are veered which does not bode well. The directional shear is also lacking for any meaningful storm organization (right now that is). The cap is gonna be pretty strong at 12C at 700 mb, but the temperature climbing into the mid-90s should offset that pretty well. All in all its pretty conditional right now. If theres more turning in the lower levels by tomorrow we should be in business.

 

[Chip Redmond]

The omega blocking pattern/ridge in the central states trying to break down and shift east appears that it will be unsuccessful. The ridge should persist, although a shortwave will make a run for it though across the Great Lakes as the Atlantic upper level cut-off low will weaken slightly. The persistence of the ridge will prohibit winds to back any in the short term. Already, timing is an issue with the shortwave as well with the greatest forcing arriving well after dark and pretty much in the early morning hours of Sunday. WRF is hinting at a decent sized 500mb vort max arriving in northeast Ohio Saturday afternoon. This is likely the result of a ongoing MCS from later today that will cross Canada from Michigan and then reenter the states. That looks to be the only forcing that will permit any convection to occur tomorrow. Tail-end type storms on the outskirts of the system and perhaps a few storms trying to fire on an outflow are possible, but besides that, I don't see a very good chance at organized severe weather tomorrow. It will be mostly dependent on convection from this afternoon as well.

Chip