textproduct: Wilmington

KEY MESSAGES

1) Showers and thunderstorms with very heavy rainfall are expected at times from Thursday night through Saturday.

2) Temperatures increase steadily after Fri, with heat indicies becoming a threat Sun/Mon.

DISCUSSION

KEY MESSAGE 1) Showers and thunderstorms expected to begin as early as Thurs morning and dominate the forecast from Thurs afternoon through Saturday. A significant increase in moisture begins on Thurs, then gets pushed out of the region late Sunday. Rain could begin as early as overnight Wed in the NW CWA. Expect an increase in shower/tstorm coverage Thurs afternoon and evening, becoming prevalent overnight Thurs through Fri night.

An increase in theta-e air should increase pwat to 2"+, linger along/south of the Ohio thru Sat. Any precip beginning overnight Thurs could be torrential and increase flooding threat over the region. This is day 4 of fcst, so moderate-heavy rain will be honed in on with later forecasts, as well as any severe threat.

Mid and upper level energy will be squeezed out early Thursday in the NW, as the gradient tightens ahead of an approaching s/w. The upper atmospheric low pressure system retreats to the n, though a surface boundary looks to develop overnight Thurs and maintain a presence along/just N of Ohio River through Sat.

Though details are still far from worked out, there does appear to be some potential for hazardous weather during the Thu-Fri-Sat time frame, with Friday appearing the most likely day at this point. Neither instability or shear look higher-end, so it remains to be seen when either (or both) might be maximized over the area. Some models are depicting a surface low moving through the region -- if that occurred, it could increase both forcing and low-level shear, and possibly increase the severe threat as a result. This kind of pattern also supports repeated rounds of deep convection with very heavy rainfall, so flooding threat is also increased. Still a long way from any certainty, but some severe and/or flood potential exists late this week.

KEY MESSAGE 2) Temperatures increasing going into early next week.

After rain-cooled yet muggy air hampers highs on Friday, overnight low and then subsequent temps through the remainder of the forecast will show a steady increase. While the excessive humidity looks to be pushed S/SW later Sun, temperatures will show a strong rebound into the upper 80s. Mon will be a bit drier, but temps 90+ will also be in play. This will bring a threat of excessive heat for these days and beyond the valid forecast period.

While there will be many potential changes to the forecast for the new week, the signals attm felt strong enough to necessitate some inclusion in the discussion.

AVIATION /18Z TUESDAY THROUGH SUNDAY/

Gusts earlier in the forecast have only come through at CMH/LCK this afternoon, and I ran with a persistence forecast through late day. This gave me the opportunity to remove the cu as winds lowered slightly/lost any gusts and then create a new group with variable wind and a more ovc ci deck. All of this is insignificant for the most part and conditions will be VFR through the period, with an occasional bkn deck aoa 4kft.

One exception to VFR conditions is expected to occur at CVG. A reasonably strong inversion will set up, and numerical guidance are all touching on a MVFR vsby restriction here in the predawn hours. KLUK is also showing a typical pattern for morning fog, and looks to go IFR. At CVG, it was odd to see a 7-8 deg sfc dewpoint depression with an inkling of fog. The recent rainfall and robust inversion led me to jump on this signal for inclusion in this latest 18Z forecast.

Fog forecasting is a fickle beast in our CWA, and this could just end up being a very shallow ground fog under the 6' height temperatures are measured at.

OUTLOOK...Thunderstorms are possible at times from Thursday through Saturday.

ILN WATCHES/WARNINGS/ADVISORIES

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