093 FXUS61 KCLE 210410 AFDCLE Area Forecast Discussion National Weather Service Cleveland OH 1110 PM EST Mon Jan 20 2025 .SYNOPSIS... High pressure builds through the Ohio Valley tonight. A re- enforcing cold front crosses from west to east on Tuesday. High pressure builds back in Tuesday night into Wednesday. && .NEAR TERM /THROUGH TUESDAY NIGHT/... 1100 PM EST Update... The band of lake effect snow over Lake Erie has shifted south a bit more than expected which has allowed moderate snow to move onshore. High res guidance doesn't have the wind shifting much through the overnight so several inches of snow accumulation is possible in northern Erie County, PA, primarily from roughly Presque Isle State Park to North East. Moderate to periodically heavy snowfall in addition to blowing/drifting snow will result in slick travel and reduced visibilities. A Winter Weather Advisory has been issued through 7AM/12Z, but can't rule out needing to extend the advisory if the band is slow to shift north Tuesday morning. There may be some light snow accumulations from northeastern Lake County into northern Ashtabula County, but expect impacts to be limited. 915 PM EST Update... Overall, the forecast remains on track and no major changes were needed with this update. Temperatures across most of the area are in the single digits and a few spots are approaching zero degrees. The band of lake effect snow that is impacting western NY will generally stay offshore tonight, but can't rule out light snow periodically grazing northern Lake, Ashtabula, and Erie (PA) counties. Previous Discussion... Lake effect snow has just about lifted offshore of Erie County, PA and should be able to let the Winter Weather Advisory expire at 4 PM. This snow band will sit just offshore tonight into early Tuesday and could graze the Erie County shoreline at times. Otherwise, we should be done with LES for the time being. High pressure and the cold, dry arctic airmass will lead to a cold but quiet and clear evening and night. Interestingly enough, some cumulus have developed this afternoon but will quickly dissipate with sunset. Lows tonight are still expected to generally fall to a -5 to 5 above range. It likely will be hard for winds to decouple tonight, though a narrow surface ridge axis will extend out of the Ohio Valley and towards central and east-central Ohio. With at least some fresh snow in that area, it's possible some lower-lying areas decouple and see temperatures tank locally more than expected. Wind chills will generally bottom out in the -14 to -22 range tonight, which is solidly within the "advisory" realm. A shortwave and surface cold front will move across the region from west to east on Tuesday, bringing a modest increase in synoptic moisture and some lift to the region. Some mid-level clouds should spread in late tonight into Tuesday morning as PVA/height falls ahead of the shortwave and modest low to mid- level warm air advection/isentropic lift arrive. Some very light snow could break out ahead of the cold front Tuesday due to the isentropic lift. The more interesting feature will be the cold front itself. Decent low-level convergence, along with sufficient low-level moisture and steep low-level lapse rates, will yield potential for snow showers along and just ahead of the front. This forecaster was a bit amused to see forecast soundings depicting just a little bit of CAPE ahead of the front on Tuesday in such a cold airmass. In response, hit most of the area with chance (30-50%) POPs for a rather brief window from west to east on Tuesday. Have lower POPs (10-20%) in the Toledo area and actually increase to likely (60-70%) from our eastern couple tiers of Ohio counties into Northwest PA. Snow amounts will generally be less than 0.5" west of I-77, with locally up to an inch possible farther east. There could be a brief period of travel annoyances on Tuesday with any snow. While amounts are light, it will be quite cold and any measurable snow will stick to roads. Also, there could be a convective component along the front, leading to brief intensity with some snow showers. Given the cold and dry arctic airmass, most or all of the clouds and snow growth will take place above the preferred dendritic growth zone on Tuesday. This will likely mean smaller flakes which won't have an exceptionally high snow to liquid ratio, but could effectively reduce visibility. Highs on Tuesday will generally warm to a 5 to 12 degree range, with a bit of a non-diurnal trend possible in Northwest OH with cold air advection kicking in during the afternoon behind the frontal passage. Wind chills recover a few degrees Tuesday afternoon, though will struggle to warm above -5 to -15. The front exits east Tuesday night with high pressure building quickly out of the Ohio Valley, leading to a dry and mainly clear night. Lake effect will try to briefly come back onshore into Erie County, PA right behind the front before lifting back over the lake. Don't want to entirely rule out a quick inch or so of "dusty" snow if that happens. Otherwise, the big story will be the cold. Clearing skies, rather fresh snow pack across the eastern two-thirds of our area, a "refreshed" cold airmass right behind the front, and slackening pressure gradient will set the stage for surface temperatures to plummet Tuesday night. Have air temperatures falling to -5 to -15 in general, slightly warmer near the eastern lakeshore. Lighter winds will work against extremely cold wind chills, though it may be hard for winds to go completely calm. Wind chills will bottom out -20 to 25 across most of the area, and still can't rule out a potential need to eventually upgrade parts of the area to an Extreme Cold Warning (criteria is -25F). With dew points expected to drop to the -15 to -20 range, room is there for low-lying and less- urban areas to drop to near or below -20 degrees if they're able to decouple. Hard to get this in the forecast grids, though did lower temperatures from the prior forecast a bit, especially in lower-lying areas where we have relatively lighter winds in the forecast. Infrastructure issues caused by the cold will peak Tuesday night-early Wednesday. && .SHORT TERM /WEDNESDAY THROUGH THURSDAY NIGHT/... Slowly will be coming out of the coldest air of the season for the area, with teens Wednesday and a significant jump Thursday back into the 20s with some brief low level warm air advection. 850mb temperatures climb into the -10C range Wednesday as the Canadian high pressure system that brought the cold airmass shifts east of the CWA and a clipper system tracks into the northern Great Lakes. Expecting a cold front shortly thereafter from the surface low over the northern lakes on Thursday bringing a few snow showers with it along with a weak reinforcement to the chilly air that has plagued the region for the month of January. The pattern is very progressive with that cold front off to the east very quickly and high pressure back into play for Thursday night. Some questions in the forecast at this point with the potential for lake effect behind the cold front. Favorable lake effect snow wind directions are not a slam dunk and might be a little more variable during the Thursday night period, so only carrying low POPs/snow amounts at this time, but will be something to watch going forward. && .LONG TERM /FRIDAY THROUGH MONDAY/... Pattern aloft becomes more zonal, which will allow temperatures to push towards the freezing mark heading into the weekend as more moderate air that has been pinned well to the south is allowed to creep back northward. No major systems on the horizon, but could see a couple weak troughs aloft push through in the long term period, largely benign. Still going to be largely below normal for temperatures as we head into the last week of January. && .AVIATION /06Z Tuesday THROUGH Saturday/... VFR with some mid-level clouds will persist through tonight with ceilings lowering to low-end VFR or MVFR as a cold front moves east across the area Tuesday. A band of lake effect snow should remain to the north of KERI through tonight, but can't rule out light snow periodically clipping the terminal. Snow showers associated with the cold front should generally remain east of a line from KTOL/KFDY and will be relatively fast-moving. A brief period of IFR visibilities is possible at eastern terminals, but confidence in snow coverage is too low to include prevailing sub-MVFR conditions. Opted for PROB30 for reduced visibilities for the time being. Ceilings should improve relatively quickly once precipitation ends. Winds will be out of the southwest around 6 to 12 knots tonight with winds becoming more westerly and increasing to 10 to 15 knots with gusts to 20 to 25 knots Tuesday afternoon. Outlook...Mainly VFR expected Tuesday night through early Thursday. Non-VFR possible in scattered snow showers Thursday. && .MARINE... Freezing Spray in the open waters east of Avon Point continues to be a potential hazard through Tuesday night with southwest wind gusts reaching 25-35kts. The Heavy Freezing Spray Warning remains in effect during this period. As the lake becomes less turbulent through mid week and into the end of the week, continued ice coverage is favorable with the coldest airmass of the season currently in place. Mainly iced over from Vermilion west, although lots of ice shifting still taking place with wind direction changes. Winds do not come down below 15kts until Thursday. Small Craft Advisory issuance has been suspended until further notice for nearshore waters from Maumee Bay to Ripley due to extensive ice cover. && .CLIMATE... Arctic air persists through Wednesday. The coldest temperatures are expected late Tuesday night into early Wednesday morning with forecast temperatures approaching record lows for 1/22. Below are the current record low temperatures for 1/21-22. Date Toledo Mansfield Cleveland Akron Youngstown Erie 01-21 -20(1984) -19(1985) -17(1985) -24(1985) -20(1985) -16(1985) 01-22 -12(1936) -10(1936) -10(1936) -13(1936) -9(2022) -7(1970) && .CLE WATCHES/WARNINGS/ADVISORIES... OH...Cold Weather Advisory until 10 AM EST Wednesday for OHZ003- 006>014-017>023-027>033-036>038-047-089. PA...Cold Weather Advisory until 10 AM EST Wednesday for PAZ001>003. Winter Weather Advisory until 7 AM EST Tuesday for PAZ001. MARINE...Heavy Freezing Spray Warning until 1 AM EST Wednesday for LEZ166>169. && $$ SYNOPSIS...Sullivan NEAR TERM...Maines/Sullivan SHORT TERM...26 LONG TERM...26 AVIATION...Maines MARINE...26 CLIMATE...