379 FXUS61 KCLE 170853 AFDCLE Area Forecast Discussion National Weather Service Cleveland OH 353 AM EST Thu Dec 17 2020 .SYNOPSIS... A trough lingers over the upper Ohio Valley region today. High pressure will build into the area on Friday and will remain overhead through Saturday. A low pressure system will enter from the west on Saturday afternoon and move through the region on Sunday. High pressure will return to the region early next week. && .NEAR TERM /THROUGH FRIDAY/... The near term forecast is a bit of a quagmire to start as an inverted trough will linger over the region today and tonight. This feature will provide some fairly weak lift across the area and with a saturated low-level air mass in place, allow for scattered light precipitation through the day. The question, however, is what precipitation will actually fall. Saturation around 700 mb where temperatures are around -12 degrees Celsius are allowing for ice crystals in the clouds this morning and falling precipitation remains as snow. However, satellite shows that there is some ice loss over western and central Ohio, which would mean any precipitation falling is liquid and with surface temperatures below freezing, is prompting a light freezing drizzle threat. The window for ice loss appears to be primarily this morning and have reintroduced some light freezing drizzle into the forecast for some of the area. Elsewhere, snow will remain favored if it does precipitate. Colder, saturated air reenters the region this afternoon and all precipitation will switch back to snow. Accumulations today will be quite minor, featuring a few tenths of new snowfall. If there is an area to watch for higher snowfall, it would be north central Ohio around Erie, Huron, and Sandusky Counties, where snow could become somewhat lake enhanced to try to squeeze out a few more tenths of new snow accumulation. The inverted trough weakens tonight and less lift will mean less precipitation potential across the region and have PoPs coming down through the overnight. High pressure builds in from the west for Friday and drier air will end the precipitation threat. Temperatures through the period will remain December-like with 30s for highs and 20s for lows. && .SHORT TERM /FRIDAY NIGHT THROUGH SUNDAY NIGHT/... High pressure moves to the east coast Friday night allowing a warmer southerly wind to develop. This southerly flow will persist ahead of a weakening cold front that will stall over the central Great Lakes. This boundary then becomes the path for low pressure to move along on Sunday. The cold front should then cross the region by Sunday afternoon. Best chances of precipitation look to be Saturday night into Sunday. There could end up being some light accumulations of snow. Current thinking is generally an inch or less but we will monitor this potential through the end of the week. Slightly above average temperatures are expected in the short term. Highs within couple degrees of 40. Lows in the mid 20's to lower 30's. && .LONG TERM /MONDAY THROUGH WEDNESDAY/... Progressive pattern will continue into next week with another trough moving into the central Great Lakes on Monday. Not all that much moisture work with this time so precipitation amounts look to be light and mostly across the northern CWA. High pressure ridges into the area on Tuesday but is quickly nudged eastward by a stronger storm system that will lift west of the region on Wednesday. The region remains on the warm side of each of these storm systems. Highs through the longer term will remain above seasonal averages. Highs may reach the mid 40's for portions of the region on Monday and again on Wednesday. && .AVIATION /06Z Thursday THROUGH Monday/... Residual snow showers continue across the region this morning with a mixed bag of conditions ranging from MVFR to LIFR. The main snow shield is exiting the region and snow will become more scattered overnight, fleeting among the terminals. Ceilings will favor levels under 1500 ft with decent low level moisture lingering through the region. Weak lift will persist through the region on Thursday, supporting very light snow in most cases. However, there is a a chance that this precipitation may teeter into drizzle/freezing drizzle vs snow. For now, have some vicinity shower mentions in the TAFs for the periods of lighter precipitation. Regardless, MVFR or lower ceilings will be favored. Eventually, lift will become marginal enough to end the precipitation and the main aviation concern will be low ceilings overnight into Friday. Outlook...Periods of non-VFR possible with snow and/or rain showers this weekend through Monday. && .MARINE... Weakening low pressure will persist over eastern Ohio into western PA. This should keep northeast winds going on the lake into early Friday with speeds remaining under 15 knots. High pressure builds onto the lake from the south on Friday but will drift to the East Coast of the US by Friday night. Expect to see southern winds become southeast as low cold front weakens moving through the central Great LAkes on Saturday. This boundary will become the track for low pressure to follow into Sunday. The low on Sunday will bring an increase in southwesterly winds which may build waves to near 4 feet from Geneva-on-the-lake to Ripley. Strongest winds arrive at the beginning of next week. && .CLE WATCHES/WARNINGS/ADVISORIES... OH...None. PA...None. MARINE...None. && $$ SYNOPSIS...Sefcovic NEAR TERM...Sefcovic SHORT TERM...MM LONG TERM...MM AVIATION...Sefcovic MARINE...MM