806 FXUS61 KILN 241719 AFDILN AREA FORECAST DISCUSSION National Weather Service Wilmington OH 1219 PM EST Fri Nov 24 2023 .SYNOPSIS... Slightly cooler air will settle into the region today through this weekend, with light precipitation returning on Sunday. Below normal temperatures will prevail through early next week before temperatures begin to once again moderate. Drier conditions are expected Tuesday through midweek of next week. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... High pressure remains centered over the upper Mississippi River Valley today. With high pressure northwest of the area, northerly flow persists over the Ohio Valley southeast of the high. Northerly/northeasterly flow helps keep temperatures below average today with forecast highs ranging from the upper 30s to middle 40s. Some mid and upper level clouds may stick around today, but low level clouds should scatter a bit later this morning when the low level RH starts decreasing. && .SHORT TERM /6 PM THIS EVENING THROUGH 6 PM SATURDAY/... Midlevel zonal flow will become established tonight through Saturday, with quite a bit of mid/upper level moisture being carried through this quasi-zonal flow. This will be especially the case tonight through early Saturday morning where, despite a relative lack of LL moisture, skies should remain fairly opaque due to thicker mid/high level cloud cover. A gradual clearing trend should evolve as we progress into Saturday afternoon as the better cloud cover gets pushed to the N of the immediate local area. But despite the ample sunshine by the afternoon, temps on Saturday will be very similar to today, perhaps a degree or two warmer across the board. && .LONG TERM /SATURDAY NIGHT THROUGH THURSDAY/... On Saturday evening, surface high pressure will be retreating off the northeast coast, with broad mid-level WSW flow over the Ohio Valley. Attention will turn to an amplifying mid-level pattern, with a wave developing over Kansas and tracking east into Missouri by Sunday morning. The wave will accelerate slightly and pivot to the northeast as it crosses the Mississippi River and moves into the Ohio Valley on Sunday afternoon and evening. This wave will produce widespread precipitation across the ILN CWA -- though generally light, and primarily rain based on current temperature forecasts. While some theta-e advection will be occurring aloft on Sunday morning, boundary layer conditions will change very little initially, with Sunday morning temperatures expected to be largely below freezing. A period of boundary layer theta-e advection will then ensue, with temperatures expected to quickly rise through the rest of the morning and into the afternoon (highs will range from the lower 40s to lower 50s). With the onset of precipitation expected to be after 12Z, there may only be a brief window of time where temperatures are cold enough for snow -- mainly near and north of Interstate 71 in the 11Z-15Z time frame. No accumulations are expected, especially as temperatures will be solidly above freezing before the stronger forcing arrives. There has been a slight trend toward slower progression of this system, with the greatest precipitation chances not exiting the ILN CWA until Sunday late afternoon. PoPs have been increased to 80-percent area-wide. With the base of the trough still moving through the area Sunday night into Monday morning, and some cool temperatures coming into the area in the 850mb-700mb layer, there are signs that some light precipitation will continue to be possible through the night. In cold advection, this light precipitation will likely end up being snow, but with very light amounts (perhaps just flurries in most locations). Nonetheless, some PoPs were added to account for this, ending after 12Z Monday morning. It should also be mentioned that as the cold advection kicks in Sunday night, there are now signs that some 25-30 knot wind gusts could occur. A strong pressure gradient will keep some gusty winds (20-25 knots) in place through the day Monday. With most of the activity expected to remain in the northern stream (Great Lakes and vicinity) through the rest of the week, dry conditions are currently forecast through at least Thursday. Temperatures will be well below normal behind the Sunday wave, with highs in the 30s on Monday and Tuesday. Slightly warmer conditions are expected through the end of the week, but max temps in the 40s will still be a little below normal. && .AVIATION /17Z FRIDAY THROUGH TUESDAY/... Some patchy strips of MVFR ceilings have been observed this morning across the TAF sites. Any persistent MVFR ceilings are expected to scatter this afternoon as drier air works in from the north. Once ceilings go VFR, ceilings should remain VFR for the TAF period with only some middle and upper level clouds above. Northerly winds this afternoon veer to the northeast overnight before becoming light out of the east on Saturday. OUTLOOK...MVFR CIGs likely, with MVFR VSBYs possible, on Sunday and Sunday night. Some MVFR CIGs may linger into Monday. && .ILN WATCHES/WARNINGS/ADVISORIES... OH...None. KY...None. IN...None. && $$ SYNOPSIS...KC NEAR TERM...Campbell SHORT TERM...KC LONG TERM...Hatzos AVIATION...Campbell