Information is from the NWS Wilmington, OH Office

ILN Area Forecast Discussion/SKEW-T

FXUS61 KILN 201442

Area Forecast Discussion
National Weather Service Wilmington OH
1042 AM EDT Sun May 20 2018

A surface boundary enhanced by weak disturbances will be the
focus for shower and thunderstorm development today into
Tuesday. High pressure is forecast to provide drier conditions
starting Wednesday and continuing for the rest of the work week.


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14Z surface analysis shows that the boundary has sagged into southeast Indiana and across southern Ohio. The shallow stable layer should mix out through early afternoon which will allow the effective boundary to jump back north closer to I-70. Convergence will be weak along the boundary, but it should serve as a focus for pooling moisture which will enhance instability along it compared to the rest of the region. High resolution guidance has locked on to a disturbance moving out of dying convection to the west and then initiating storms in eastern Indiana near the boundary late this afternoon and then progressing east southeast across the forecast area into the evening. This looks like a damaging wind threat with some marginally severe hail not out of the question. Have adjusted corridor of higher PoPs north based on where boundary is expected by time of convective initiation.
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Storms that develop late this afternoon will continue to track across the forecast area into the evening. Later tonight, additional short wave energy may trigger more showers and thunderstorms. For Monday, thunderstorms will be possible again in the persistently unstable airmass positioned along the slow moving boundary, aided by another round of short waves embedded in the mean flow. High temperatures reaching around 80 will allow enough instability for continued thunderstorm development.
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&& .LONG TERM /MONDAY NIGHT THROUGH SATURDAY/... Active weather pattern to continue through early next week with ILN/s FA on the periphery of mid/upper level ridging. Mid level shortwave to induce a surface wave that tracks through the area Monday night and Tuesday. This will allow an associated surface front to drop southeast through the Ohio Valley Tuesday. This will offer a continued threat for showers and thunderstorms. Warm temperatures to continue with Tuesdays highs from the upper 70s northwest to the lower 80s southeast. Northwest flow aloft to develop with surface high pressure building into the Great Lakes. A lingering chance for showers/thunderstorms will persisting the southeast early Wednesday, otherwise expect dry weather. Expect highs Wednesday in the upper 70s to lower 80s. The surface high will build southeast with continued dry weather Thursday. Above normal temperatures with highs from near 80 north to the lower/middle 80s south. Southerly low level flow develops on the backside of retreating sfc high pressure Friday with mid level ridging building into the Ohio Valley. Temperatures will warm up with highs in the lower and middle 80s. Mid level flow backs ahead of a developing trof with moisture increasing Friday night. Will mention chance pops for showers and thunderstorms Friday night west and across the entire area Saturday. Warm temperatures to continue with highs Saturday generally in the middle 80s. && .AVIATION /14Z SUNDAY THROUGH THURSDAY/...
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MVFR to IFR clouds across much of the region will diminish over the next few hours. Scattered cumulus will develop this afternoon. Thunderstorms may impact the area between 21Z and 01Z with the greatest potential from KDAY to KILN. Once convection passes, expect VFR conditions during the evening. Some MVFR visibilities may develop late in the period in mist/fog. OUTLOOK...Thunderstorms possible through Tuesday.
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