The boys had this to say around 9:30 am:
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
A weak front will slowly drift to the SE into WC OH by this
afternoon, with some drier air attempting to filter E into the NW
third of the ILN FA by midday. To the SE of that, particularly near
and S of the I-71 corridor, sfc dewpoints in the upper 50s to lower
60s will support some fairly good diurnal destabilization across the
SE 2/3 of the local area by early afternoon, characterized by MLCAPE
on the order of 1000+ J/kg in these areas by 18z.
There are likely going to be two areas of storms that will be the
focus as we progress through the daytime. Firstly, although the
forcing and lift should be somewhat meager, the tightening instby
gradient, which should position itself very close/nearly parallel to
the I-71 corridor by 18z, may be just enough amidst an uncapped
environment for ISO/SCT convection to develop within this axis by
early/mid afternoon. This CI is most favored early afternoon within
a corridor stretching from near Franklin Co IN to Delaware Co OH,
particularly E of I-75 and near/S of I-71. This activity, which
should be cellular/discrete in nature, perhaps merging into small
clusters, may pose a local large hail and damaging wind threat as it
shifts to the ESE more into central/south-central OH by 21z as the
pool of instby shrinks with drier air infiltrating from the W.
Meanwhile, the second focus is going to be a better organized
MCS that will be approaching from the SW by 21z, moving into far SE
IN and N KY by 21z and expected to track to the ENE through 01z. This
will place the best severe threat early evening across the SE third
of the ILN forecast area. Some convection along a warm advection
wing ahead of the MCS is also possible. The severe threat may persist
a bit past 01z as the mature or decaying moves across NE KY and far
southern OH into mid evening, with the severe threat decreasing late
evening.
With sufficient effect bulk shear on the order of ~30-40kts and the
LL bulk shear vector oriented at approximately 250 degrees at 40kts,
any N-S or NNW-ESE oriented linear segment will bring with it an
elevated damaging wind risk, which seems most favored in parts of N
KY and far south-central OH within that 21z-01z time frame.
