943 FXUS61 KCLE 262112 AFDCLE Area Forecast Discussion National Weather Service Cleveland OH 412 PM EST Fri Nov 26 2021 .SYNOPSIS... High pressure has begun to build north across the western Great Lakes region as a surface trough lingers across the eastern part of the region. This trough will move east out of the area tonight, allowing high pressure to briefly build in Saturday. A low pressure system will move through the region Saturday night into Sunday, followed by an additional system Sunday night into Monday.A surface trough lingers behind these systems until midweek. && .NEAR TERM /THROUGH SATURDAY/... Scattered lake effect snow showers are still impacting areas in the snowbelt this afternoon. Dry air has begun to push into the area with areas along and west of I-71 seeing dewpoints in the teens. This will continue to push east, gradually ending the lake effect snow from west to east this evening into the overnight hours. This will result in little to no additional snowfall accumulation in areas of the OH snowbelt. In NW PA, the heaviest of lake effect snow has begun to move east of the area as a result of weakening thermodynamic parameters and a diminishing area of convergence along the lakeshore in Erie County. This does not eliminate the potential for lake effect as 850-mb temperatures remain between -10 to -12C and weak to moderate lake induced instability lingers. As a result, areas in the Lake Effect Snow Warning, which is valid until 7 AM Saturday, may receive an additional 1-3 inches of new snowfall, with locally higher amounts possible. Aside from snow, gusty winds up to 25mph from the west-northwest will gradually weaken to light and variable overnight. Overnight low temperatures will be in the upper 20s to low 30s. On Saturday, high pressure will build over the area briefly, allowing for dry conditions to persist into the afternoon for much of the area and warmer temperatures with highs in the upper 30s to low 40s, resulting from an increase in WAA due to south- southwest winds of 5-10 mph. Rain/snow showers will begin to creep into NW Ohio late morning/early afternoon on Saturday as another low pressure system impacts the Great Lakes region. By late afternoon/early evening, all precipitation should be only snow, with the exception along the lakeshore where it may remain above freezing. The bulk of this system impacts the area during the short term period, but for Saturday, little to no accumulation is expected. && .SHORT TERM /SATURDAY NIGHT THROUGH MONDAY NIGHT/... A weak clipper system will move west to east across the area on Saturday night. Model runs over the last 24 hours have trended slightly farther north with the low track and associated placement of precipitation developing along the 850-700mb front. To account for this, have trended pops down across the southern counties and removed any light accumulation south of Route 30. Farther north, a window of snow is possible with accumulations of a half inch to an inch. As the night progresses, dry air will wrap up from the south along with warm advection in the 925-850mb layer which could result in a change over to drizzle/freezing drizzle where precipitation lingers. Given the lack of deep layer moisture which will extend nearly as far north as Lake Erie on Sunday, much of the area will see precipitation end or become light during the morning hours. By later Sunday, an upper level trough will deepen as it crosses Lake Erie, bringing a return of deeper moisture across the snowbelt and an increase in cold advection. In the low levels, a somewhat compact trough that had been in place over the lake, will act as a focus for precipitation. This trough will swing across the snowbelt with additional light to moderate accumulations possible. Early estimates suggest accumulations of 1-5 inches with the higher amounts across inland NW Pennsylvania. Temperatures which are forecast to warm into the mid/upper 30s on Sunday may be a factor for how quickly this transitions back to snow and begins to accumulate during the late afternoon/early evening hours. Deeper moisture pulls away by Monday morning with snow tapering off. Flow will also back on Monday as the surface ridge builds into the Ohio Vally, focusing any lingering precipitation closer to the lakeshore. && .LONG TERM /TUESDAY THROUGH FRIDAY/... Prevailing northwest flow pattern will continue through mid-week while a series of shortwave troughs cross the Great Lakes and New England. Uncertainty remains in how far south the colder air extends during this time frame with temperatures in the near to below normal range. Some light precipitation is possible Monday night as a weak clipper crosses the central and eastern Great Lakes but the flow will generally be southwesterly so Lake Erie will be less of a factor. Another shot of precipitation will be possible behind a front Tuesday night into Wednesday. && .AVIATION /18Z Friday THROUGH Wednesday/... Primary aviation concern for this TAF update remains for KERI, and possibly KCLE, as lake effect snow showers continue. Currently, radar and satellite indicate light snow showers from KLPR extending east to KHZY and KYNG. The heaviest of these snow showers have a history of brief reductions of visibilities to IFR distances, however generally speaking these should keep visibilities 3SM or more. KERI remains the primary concern with snowfall as a Lake Huron connection has developed and light to moderate snow is falling. Visibilities have frequently fallen to IFR, even LIFR at times, along with lower ceilings in some of the heavier bands. This trend will continue into Saturday morning before the surface trough finally moves east, dry air moves in, and lake effect snow is cut-off. For all other TAF sites, an isolated flurry is possible, however visibilities should not be impacted from precipitation. Ceilings are expected to fluctuate between MVFR and VFR this afternoon before becoming steady VFR heights tonight. West-northwest winds sustained to 10-15 knots, gusting up to 25 knots, will persist through 00Z as high pressure begins to build over the area. Winds will become light and variable for all terminals, except KERI, late tonight. Outlook...Non-VFR possible in snow Friday through Sunday in Northeast Ohio and northwest Pennsylvania. && .MARINE... Winds have come down enough on western Lake Erie to allow the Small Craft Advisory to expire west of the Lake Erie Islands, while remaining in effect for tonight east of the Islands. East of the islands, northwest winds of 20-30 knots will continue through the evening, gradually decreasing into the 15-20 knot range by morning. Waves of 7-11 feet will decrease to 2 to 4 feet by Saturday morning. A ridge will build east across the lower Great Lakes on Saturday with winds backing around to the south ahead of the next system. This system will cross Lake Erie Saturday night, before slowly moving to New York state by Monday. West to northwest winds ramp up behind this low and additional Small Craft Advisories will be needed Sunday into Sunday night. Another ridge will build east across the region on Monday followed by another weak clipper system crossing the central and eastern Great Lakes on Tuesday. && .CLE WATCHES/WARNINGS/ADVISORIES... OH...None. PA...Winter Weather Advisory until 7 AM EST Saturday for PAZ001-003. Lake Effect Snow Warning until 7 AM EST Saturday for PAZ002. MARINE...Small Craft Advisory until 10 AM EST Saturday for LEZ146>149. Small Craft Advisory until 4 AM EST Saturday for LEZ144-145. && $$ SYNOPSIS...Campbell NEAR TERM...Campbell SHORT TERM...KEC LONG TERM...KEC AVIATION...Campbell MARINE...KEC