650 FXUS61 KILN 211049 AFDILN AREA FORECAST DISCUSSION National Weather Service Wilmington OH 649 AM EDT Sat Aug 21 2021 .SYNOPSIS... Weak high pressure will lead to patchy early morning fog with fair weather for the remainder of the day. A disturbance will interact with an unstable airmass to keep a low chance for precipitation Sunday. An upper level ridge will offer dry and warm conditions Monday. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... Weak surface high pressure will offer light winds and mainly clear skies this morning. These conditions will lead to patchy fog development -- especially in favored valley locations. Fog impacts will improve by 9-10 am with scattered cumulus clouds this afternoon. ILN/s area will be located between TC Henri off the Mid- Atlantic coast and a weak area of lift to the west. Have continued a dry forecast today with high temperatures generally in the upper 80s. && .SHORT TERM /6 PM THIS EVENING THROUGH 6 PM SUNDAY/... Diurnally driven clouds to clear with the loss of heating this evening. Light winds and clear skies will again lead to patchy fog development tonight -- especially in valley locations. Expect lows in the mid and upper 60s; A weak front and an axis of marginal instability will move into the west Sunday afternoon. There may be enough forcing to lead to showers and a few thunderstorms. Have limited pops to low chance category in the western counties and slight chance east. Highs look to range from the mid 80s west to the upper 80s east. && .LONG TERM /SUNDAY NIGHT THROUGH FRIDAY/... Mid-level high pressure will be centered over the central plains states on Sunday night as a weak disturbance drops east of the high down the Mississippi River valley. This disturbance misses the Ohio Valley to the west, providing warm and dry weather to start the work week. The next disturbance may clip the forecast area on Tuesday, allowing the return of a few isolated storms during the afternoon. Meanwhile, a more significant trough begins to shift east through southern Canada, flattening the ridge and allowing better chances of storms and a frontal system to affect the region Wednesday through the end of the week. Temperatures continue above normal through at least Wednesday as highs increase to around 90 degrees. Some moderation in temperatures returns late in the week with increased precipitation chances and decreasing heights. && .AVIATION /12Z SATURDAY THROUGH WEDNESDAY/... Weak surface high pressure has offered light winds and clear skies. These conditions have led to patchy fog development -- especially in river valleys. Have MVFR conditions at KDAY and KCMH with IFR restrictions at KLUK and KILN. Visibilities should improve to VFR by 14Z. Expect only scattered cumulus clouds during the afternoon. Diurnally driven cumulus clouds will dissipate giving way to clear skies this evening. Patchy fog is possible again tonight. Have MVFR vsby restrictions at KILN and KLCK with IFR conditions at KLUK valley location. Winds will be light through the TAF period, generally 5 knots or less. OUTLOOK...Thunderstorms are possible on Sunday afternoon, and again on Tuesday and Wednesday afternoon. && .ILN WATCHES/WARNINGS/ADVISORIES... OH...None. KY...None. IN...None. && $$ SYNOPSIS...AR NEAR TERM...Hatzos/AR SHORT TERM...AR LONG TERM...Hogue AVIATION...AR