691 FXUS61 KCLE 051130 AFDCLE Area Forecast Discussion National Weather Service Cleveland OH 630 AM EST Thu Dec 5 2019 .SYNOPSIS... A weak ridge of high pressure will build in from the southwest today. Weak low pressure moves east from the upper Midwest across the lower Great Lakes late tonight with a trailing cold front moving east across the region late tonight into tomorrow morning. Strong high pressure will move southeast to the Ohio Valley by Saturday morning and move east to the New England coast by Sunday. Low pressure will slowly move east across the Great Lakes region on Monday and Tuesday with high pressure beginning to build in from the west on Wednesday. && .NEAR TERM /THROUGH FRIDAY/... Raised pops slightly to adjust for radar trends of lake effect snow. Have allowed the Winter Weather Advisory for Geauga County to expire given the expected downtrend of lake effect snow. Less than an inch of snow is still possible in Geauga County through the morning hours. Around an inch of additional accumulations possible in Ashtabula and Crawford, with an additional 2 inches possible in southern Erie County. Original Discussion... Radar and satellite trends over the past several hours show a downward trend in lake effect snow intensity and coverage. This is expected to continue as drier air approaches from the west, decreasing the amount of moisture available. However, there is still a fair amount of snow expected through this morning, especially for inland parts of northwest Pennsylvania, where as much as 2 to 4 inches of additional snow can be expected. Lake effect snow is expected to end for the secondary snow belt by 12 UTC this morning and then slowly decrease in coverage from west to east this afternoon, ending for northwest Pennsylvania by 00 UTC Friday. In coordination, cloud cover will also slowly decrease from west to east, allowing many to finally see some sunshine this afternoon. Areas with the most sunshine, such as central and northwest Ohio, may have high temperatures eclipse 40, while northeast Ohio stays in the mid to upper 30s and northwest Pennsylvania in the low to mid 30s. Very weak low pressure of around 1008 mb has developed over the northern Great Plains this morning and is expected to move east across the upper Midwest today and the lower Great Lakes tonight. Forcing with this low pressure system is weak and moisture content is rather low. However, it's enough to introduce the chance for rain/snow in northwest Pennsylvania late tonight into early Friday morning. Very light scattered rain showers may overspread parts of northeast Ohio and central Ohio late Friday morning into early Friday afternoon. Light lake effect snow will follow for northwest Pennsylvania and far northeast Ohio after the low pressure's trailing cold front moves east across the area Friday afternoon. Temperatures will be near 40 late Friday morning into early Friday afternoon with a slow decline following the frontal passage. && .SHORT TERM /FRIDAY NIGHT THROUGH SUNDAY NIGHT/... Light snow showers will linger in mainly NW PA on Friday night with lingering northwesterly flow ahead of the building surface high. Light snow is expected during the evening but moisture depth and ice content in the cloud will become questionable by morning as moisture strips away at 850mb. Sufficient low level lift and orographic effects may result in a light precipitation continuing overnight and will need to keep an eye on potential for light freezing drizzle before precipitation comes to an end. Elsewhere lows on Friday night will depend on where clouds clear out. Expecting the eastern half of the area to hold onto clouds while NW Ohio and possibly portions of north central Ohio attempt to clear out. As long as clouds clear in the west, lows in the lower 20s are possible while lows in the upper 20s will be more likely downwind of Lake Erie. Ridging both at the surface and aloft will move overhead on Saturday. Southerly flow and warm advection will develop Saturday night into Sunday with cloudy skies returning. Good moisture advection is expected by Sunday night ahead of the next trough with chances of rain expanding overnight. && .LONG TERM /MONDAY THROUGH WEDNESDAY/... Energy diving south out of Canada will lead to amplification of the upper level trough over the Plains Monday and Monday night. A wave of low pressure is expected to develop ahead of the deepening trough and track northeast through the Central Great Lakes. This will provide good support for a window of rain focused in the Monday afternoon through Monday night timeframe. Most areas will also see above normal temperatures in the 50s during this time. Low pressure will continue northeast into Quebec on Tuesday pulling a strong cold front with arctic origins east across the area. Models are favoring a westerly flow setting up across Lake Erie in the wake of this cold front which could signal a lake effect snow set-up for areas closer to Lake Erie. It is a little soon to have confidence in the orientation of the trough and favored snowfall areas but 850mb temperatures falling to near -20C will bring lake effect snows to portions of the area. There is high confidence in below normal temperatures for the middle of next week. && .AVIATION /12Z Thursday THROUGH Monday/... Light lake effect snow continues this morning, though with far less impacts. MVFR conditions are isolated to KYNG and KERI this morning and possible into the afternoon. Snow showers should continue to slowly decrease in coverage today as drier air arrives from the west. West and northwest winds will continue to slowly weaken and back to the southwest during the afternoon/evening hours today. Another system with precipitation begins to approach KERI towards the end of this TAF cycle with MVFR possible at the end of the TAF cycle near KERI and KTOL. .OUTLOOK...Non-VFR possible on Friday and Friday night with rain/snow showers. Non-VFR likely late Sunday through Monday with rain. && .MARINE... The Small Craft Advisory has expired west of the Islands and will gradually end from west to east through this evening. Northwest winds of 15 to 25 knots will back to westerly and slowly decrease. Waves of 4 to 7 feet will also gradually diminish today as high pressure expands east across Lake Erie. A weak area of low pressure is forecast to slide east across the lake tonight, pulling a cold front south behind it on Friday. Waves of 3 to 6 feet will develop again on Friday and Small Craft Advisories will likely be needed east of Vermilion Friday afternoon and evening. A large area of high pressure will build east across the lakes on Saturday, reaching the East Coast Sunday. A warm front will move north across Lake Erie on Sunday followed by a cold front on Tuesday. Small Craft Advisories will be needed again begin on Tuesday afternoon and continuing through the mid-week period. && .CLE WATCHES/WARNINGS/ADVISORIES... OH...None. PA...Winter Weather Advisory until 10 AM EST this morning for PAZ003. MARINE...Small Craft Advisory until 7 PM EST this evening for LEZ148- 149. Small Craft Advisory until 1 PM EST this afternoon for LEZ144- 145. Small Craft Advisory until 4 PM EST this afternoon for LEZ146- 147. && $$ SYNOPSIS...Saunders NEAR TERM...Saunders SHORT TERM...KEC LONG TERM...KEC AVIATION...Saunders MARINE...KEC