textproduct: Wilmington

WHAT HAS CHANGED

Increased storm chances for near and north of the I-70 corridor for mid afternoon through most of the evening. Some isolated strong to severe storms may be possible in these areas during this stretch.

KEY MESSAGES

1) Scattered to numerous showers and storms are expected to develop this afternoon though this evening along a narrow corridor near/north of I-70. Some isolated strong to severe storms may be possible.

2) A weak cold front will push through the region Friday evening into Friday night, bringing renewed chances for showers and storms. Another system will impact the region Monday into Monday night, with some severe potential possible late Monday.

DISCUSSION

KEY MESSAGE 1)

An initial band of disorganized showers and storms continues to drift to the SE across portions of N/NE KY and far srn OH. With a lack of any notable instby within this corridor, this activity is expected to remain sub-severe as it continue to clear the local area.

Once we get to mid afternoon, focus will turn to CI, expected across parts of WC and central OH coincident with a narrow axis of WNW to ESE LL convergence that will be maintained near/north of I-70. This will provide enough lift, amidst a largely uncapped environment with ~500-1000 J/kg MLCAPE, to promote the development of an axis of scattered to numerous showers and storms extending from WC through central OH. CI is expected around 20-21z, with the greatest coverage/intensity of storms likely through about 00z before a decrease in storm strength/coverage evolves past sunset with the combined loss of diurnal instby and the environment gradually being worked over. Deep-layer shear will be relatively weak, on the order of about 20-25kts, suggesting that storms should be rather disorganized and will tend to conglomerate into clusters through time and become outflow dominant. Nonetheless, some gusty winds may be possible in the strongest storms, along with some small hail. Some isolated damaging winds and large hail cannot be ruled out, but do think this will be quite spotty in nature, if it occurs at all.

Another item to keep in mind with the afternoon/evening activity is going to be the nearly parallel overlap between the convergent axis (source of lift) and the steering-layer flow, suggesting that some brief training of storms will be possible. This may lend itself to repeated rounds of downpours in an isolated manner, with locally around an inch of rain possible in a few spots, particularly from/near Mercer to Licking Cos OH.

KEY MESSAGE 2) A cold front will move through the OH Vly Friday evening into early Friday night, bringing with it some scattered showers and storms. The forcing will weaken with eastward extent into Friday night, with a less favorable thermodynamic environment as well. While we are expecting showers and storms with the FROPA across at least parts of the area, the prospect of strong/severe storms remains quite low at this juncture. If -- and it is a big if -- there is going to be any severe potential locally Friday evening, it would likely be focused near/W of I-75 and near/S of I-70 into the Tri-State and parts of SE IN and N KY. But confidence on this scenario remains low. Drier conditions should evolve area-wide from W to E by early Saturday morning, setting up a dry and seasonably mild weekend.

Midlevel ridging will build into the OH Vly Saturday into Sunday before a potent system moves into the mid MS Rvr Vlys and OH Vlys for Monday into Monday night. While the specifics of this system are still to be determined, the pattern suggests the potential for some severe storms across at least portions of the OH Vly (highest probabilities favored just W and S of the ILN FA). Ensemble and various AI guidance suggests a S/W digging into the region during this time, with an expanding warm sector out ahead of it early Monday. This strengthening system will likely induce a deepening sfc low, which is fcst to migrate from MO into IA/WI through the daytime Monday, with an attendant cold front flanked to the S. LL and deep- layer flow fields will increase accordingly, setting up the potential for at least some severe activity, potentially leading into Monday night, across parts of the OH/TN Vlys. This is mentioned here strictly for awareness purposes as confidence regarding location, timing, and severity is still a bit too low to include in the HWO at this time.

AVIATION /18Z WEDNESDAY THROUGH SUNDAY/

The AM SHRA/TSRA has dissipated and cleared the local area to the S, with the expectation for redevelopment near/N of I-70 by 21z. While most of this activity may stay just to the N of nrn sites, the highest probs for TSRA will likely focus near KCMH/KLCK between about 22z-01z. PROB30s were maintained in the fcst at this juncture at KCMH/KLCK/KDAY, although TEMPOs may be needed should mesoscale and radar/satellite trends dictate. Activity should wane in coverage and intensity past sunset with the loss of diurnally-driven instby and loss of instby due to the environment becoming worked over.

Further to the S, dry conditions will be maintained for KCVG/KLUK/KILN, with SCT VFR Cu through the evening before some mid clouds (convective debris/blowoff) overspread the area for several hours late this evening. Suppose that some patchy BR cannot be ruled out at nrn sites if the terminals receive substantial rain with the late afternoon/early evening activity, but confidence was too low to mention in the fcst at this time.

SW winds of 10-12kts, with gusts 15-20kts, will be maintained through the afternoon before decreasing to around 5kts overnight. This is outside of any convectively-driven adjustments to wind speed/direction. SW winds of 10-12kts, with gusts around 15-20kts, are again expected Thursday afternoon with some VFR Cu.

OUTLOOK....MVFR conditions will be possible Friday afternoon into early Friday night, along with a chance for thunderstorms.

ILN WATCHES/WARNINGS/ADVISORIES

OH...None. KY...None. IN...None.