811 FXUS61 KCLE 192233 AFDCLE Area Forecast Discussion National Weather Service Cleveland OH 633 PM EDT Tue Oct 19 2021 ...00z TAF Aviation and Near Term Forecast Update... .SYNOPSIS... High pressure will persist over the area through Wednesday, followed by a low pressure system and cold front on Thursday. A trough may linger across the area into Saturday. && .NEAR TERM /THROUGH WEDNESDAY NIGHT/... 630 pm update... The weather is very quiet this evening and overnight. No changes were needed to the ongoing forecast at this time. Previous discussion... Quiet weather is expected through Wednesday as upper- level ridging and high pressure persists across the region. Despite warm temperatures from this afternoon, clear skies will allow radiational cooling to bring temperatures down into the mid to upper 40s tonight. Above average temperatures in the low 70s are forecast for Wednesday as the ridge continues to build, resulting in pleasant weather conditions under mostly sunny skies. By Wednesday night, a strong upper-level trough approaches from the west. Strong forcing and ample moisture content content will result in the increase of precipitation chances late Wednesday night with a slight chance of a thunderstorm for the western portion of the CWA. && .SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/... A quick moving, rather potent upper-level shortwave trough will move across across the Great Lakes region Thursday morning into the afternoon hours. Early on Thursday, a cold front will move across the area. Models continue to suggest an additional cold front moving through the area again Thursday night. Although overall forecast instability remains low for Thursday, there is vertical speed sheer over the area. That coupled with an associated moisture axis and upper level support, there is a high shear-low CAPE severe weather potential on Thursday. Primary concern will be the mixing down of stronger winds aloft in thunderstorms. Have opted to include chance of thunderstorms in the forecast, however it will be difficult for storms to develop large enough to produce thunder, so this will need to continue to be monitored. Currently, SPC has issued a Day 3 Marginal Risk for severe weather for the eastern tier of counties. High temperatures on Thursday will be in the mid to upper 60s with overnight lows dipping into the mid 40s. On Friday, a weak shortwave will again move along the southern edge of the upper level trough, providing support for additional showers. The bulk of moisture appears to remain along the southern tier of counties during the day Friday, shifting northeast towards NE OH and NW PA for the overnight hours. This will be the primary source of shower development during the day before switching over to a mix of synoptic and lake effect rain showers overnight. The short term remains an active weather pattern, but overall QPF remains fairly low with the bulk of it occurring Thursday. With each passing shortwave, a cooler airmass makes it way further over the area, allowing for highs on Friday to be in the mid to upper 50s and overnight lows in the low 40s. && .LONG TERM /SATURDAY THROUGH TUESDAY/... The start of the weekend will again be associated with a passing shortwave trough aloft as an upper-level low center north of the Great Lakes will continue to rotate in nearly the same location. This will allow for the continued cool air to be advected into the area and for northwesterly winds to persist. With this orientation, lake effect rain showers are likely for the snowbelt areas on Saturday through the evening hours. After Saturday, models begin to diverge in agreement with handling the next low pressure expected to develop somewhere in the central part of the country early next week. Most notable of this period will be the more seasonably cool temperatures in the 50s persisting through the period and the potential of the first frost as overnight temperatures dip down into the low 40s, possibly into the 30s. && .AVIATION /18Z Tuesday THROUGH Sunday/... VFR weather will continue for pilots flying in and out of northern Ohio and northwest PA during this TAF period. High pressure is over the region with mostly clear skies. Winds will be from the southwest around 5 to 10 knots now through Wednesday afternoon. Outlook...Non-VFR possible in showers and isolated thunderstorms Wednesday night into Thursday. Non-VFR likely in lower ceilings Thursday night into Friday. Non-VFR may persist Friday into Saturday with lower ceilings and scattered showers. && .MARINE... Currently, a Small Craft Advisory is in effect for the eastern basins through Wednesday afternoon as the lake sits on the northern edge of a high pressure system. This high pressure over the eastern U.S. will continue to drift eastward through Wednesday afternoon. On Wednesday evening, a low pressure will move into the western Great Lakes, shifting winds to southwesterly ahead of the system. By Wednesday night/Thursday morning, winds will again increase to 15-25 knots resulting in the likely need of an additional Small Craft Advisory for much of Thursday. Once the associated cold front moves east of the area, winds will shift to northwesterly and weather to 10-15 knots across the lake. These conditions will persist through the weekend. && .CLE WATCHES/WARNINGS/ADVISORIES... OH...None. PA...None. MARINE...Small Craft Advisory until 2 PM EDT Wednesday for LEZ147>149. && $$ SYNOPSIS...Saunders NEAR TERM...Griffin/Saunders SHORT TERM...Campbell LONG TERM...Campbell AVIATION...Griffin MARINE...Campbell