FXUS61 KILN 301036 AFDILN Area Forecast Discussion National Weather Service Wilmington OH 636 AM EDT Wed Apr 30 2025 .SYNOPSIS... Frontal boundary stalls out near the Ohio River today. This front eventually lifts back northward as a warm front, which will result in periods of showers and thunderstorms through tonight. Thunderstorm chances increase on Thursday with additional energy moving through. The pattern looks to remain unsettled through at least the beginning of the weekend as an upper level trough persists over the Ohio Valley. && .NEAR TERM /THROUGH TONIGHT/... Showers have shifted southeast of the region this morning, but the progression of the cold front has slowed. This is resulting in some pooling moisture and thus surface visibility reductions for portions of southern OH/northern KY and southeast IN. Dense fog is very patchy, so will just issue an SPS to highlight some of the reduced visibilities early this morning. Dry weather conditions will initially return for the beginning of the day across the CWA. However, this stalled front near the Ohio River will act as a source of lift, which will interact with a relatively warm and humid air mass that persists for locations in southern OH into northern KY. Given this setup, some CAMs try to initiate isolated shower/storm development near the Ohio River this afternoon. Any storm that spawns could produce small hail and locally gusty winds. While severe chances remain low today, it is still a non-zero threat. A gradient in highs and especially surface dewpoints will be expected today. Highs near the I-70 corridor will be in the upper 60s to lower 70s, with dewpoints being more pleasant in the mid-40s to near 50. Further south, highs will approach the middle to upper 70s, but dewpoints will be in the upper 50s to middle 60s, making it feel a lot muggier. && .SHORT TERM /THURSDAY/... The stalled front will actually begin to lift as a warm front late this evening and continue through the overnight hours. As the front lifts northward, episodic showers and thunderstorms will be possible through a good chunk of the night. These storms will be elevated, so not anticipating a severe threat. By daybreak Thursday, the front will be located near the I-70 corridor and continue lifting northward. The ILN fa will be firmly planted in the warm sector of a surface low developing from a robust shortwave propagating northeastward from the Ark-La-Tex region. Shower and thunderstorm chances will greatly increase by Thursday afternoon, with the potential for multiple rounds of storms. It does appear that a complex of storms will initiate during the afternoon and quickly develop into a QLCS (which would be the primary severe threat). SBCAPE values could increase to 1000-1500 J/kg just before storms build in. Wind shear profiles show sfc-3km values near 30 kts, which would help promote some organize convection. Hodographs are more straight given the unidirectional flow out of the southwest, so currently not anticipating a tornadic threat. The primary threat would be damaging straight-line winds, with hail being a secondary threat. && .LONG TERM /THURSDAY NIGHT THROUGH TUESDAY/... Showers and thunderstorms will be ongoing at the beginning of the period, with some strong storms still possible. The more robust activity will diminish through the evening as upper support lifts northeast and instability decreases. However, some showers and thunderstorms may linger with a weakening surface boundary in the area. Northern stream short wave will dig southeast Friday into Friday night. This, along with diurnal heating, will be sufficient to bring an increased chance of showers and thunderstorms again during the day. This will continue into Friday night as weak low pressure and a cold front finally move through. At this point, guidance diverges as the flow transitions into a blocky pattern. The GFS and much of its ensemble system are quite progressive with the trough, not closing it off until reaching the Maritimes, allowing high pressure to build into the region and predominate. Meanwhile, the ECMWF and CMC along with many of their respective ensemble members close off a low near or west of the Appalachians which then meanders about the region through the rest of the period. Needless to say, these two scenarios would result in a substantial difference in sensible weather. The NBM and the lag built into that is still pretty optimistic. But with the trends seen in the ECE and GEPS, have begun to trend the forecast to more clouds and low PoP chances. && .AVIATION /10Z WEDNESDAY THROUGH SUNDAY/... Cold front has finally passed through all the terminals. Winds will continue to veer clockwise through the rest of today, eventually shifting to the southeast by the afternoon. Surface winds will remain around 5-10kts through the majority of the period. Did highlight increased surface winds and gusts at KCVG for the extended taf. The front stalls out south of the Ohio River today, which could result in additional thunderstorm development late in the day today, mainly for our southern terminals. Shower/storm potential will shift northward through the night as the stalled front now lifts back north as a warm front. Models keep any convection pretty isolated, so have not yet included in the TAFs, but a mention may be needed at some point depending on how hi-res models trend. OUTLOOK...MVFR/IFR conditions likely Thursday into Thursday night along with a chance of thunderstorms. MVFR conditions possible Friday into early Saturday. && .ILN WATCHES/WARNINGS/ADVISORIES... OH...None. KY...None. IN...None. && $$ SYNOPSIS...Clark NEAR TERM...Clark SHORT TERM...Clark LONG TERM... AVIATION...Clark