892 FXUS61 KCLE 182149 AFDCLE Area Forecast Discussion National Weather Service Cleveland OH 549 PM EDT Wed Sep 18 2019 .SYNOPSIS... High pressure over New England will continue to drift slowly south tonight and Thursday reaching the Mid-Atlantic states on Friday. The high will finally weaken and drift offshore Sunday as a cold front approaches our region from the west. && .NEAR TERM /THROUGH THURSDAY/... Most of our forecast through tomorrow morning remains valid. Only change was to freshen our sky grids based on observed trends and NAM12 guidance. Even so, skies will likely trend clear or mainly clear as high pressure remains in control. PREVIOUS DISCUSSION...Models show a fairly sharp upper ridge axis on a line from roughly Indiana, across the Great Lakes into Quebec. This ridge will remain across the region through the near term period, eventually drifting east Saturday. At the surface, high pressure over New England will continue to drift slowly south tonight and Thursday, eventually reaching the Mid- Atlantic states Friday where it will stall. This high will remain in control of weather across northern Ohio and nwrn PA through the near term with mostly clear skies and light east to southeast winds. Temps guidance has been on the cool side recently and given the dry air and abundant sunshine will go a few degrees above guidance especially for Thursday. && .SHORT TERM /THURSDAY NIGHT THROUGH SATURDAY NIGHT/... An Omega like block in the upper level weather pattern will continue for the end of the week with a large and expansive upper level ridge from the Great Lakes region down to the Gulf Coast region. Upper level heights will continue to increase on Friday afternoon with the ridge starting to break down by late Saturday. The warmest weather will likely be either Friday afternoon and Saturday afternoon. MOS guidance has been way too cool by 5 to 7 degrees recently. We bumped up high temperatures for the end of the week to the middle and upper 80s and that might be too conservative given the very large upper level ridge. An upper level trough begins to move across the Great Lakes region and breaks down the ridge late Saturday into Sunday. A slow moving frontal boundary will also be crawling through the Great Lakes region this weekend. Showers and thunderstorms will be likely late Sunday, Sunday night, and wrapping up on Monday. The heaviest rainfall will remain to our west across the Midwest. Guidance indicates a general half inch to one inch of rainfall can be expected with the highest rainfall amounts across northwest Ohio. && .LONG TERM /SUNDAY THROUGH WEDNESDAY/... The front will be slow to clear the area on Monday with lingering showers across the eastern and central portions of the area. Drying conditions and clearing skies will be slow from northwest to southeast. Weak high pressure moves in across the area on Tuesday with more active weather moving in the region by the middle of next week. && .AVIATION /18Z Wednesday THROUGH Monday/... High pressure dropping south from Quebec will keep skies clear through tonight and into Thursday. The airmass is fairly dry as well so do not expect much early morning fog. Will keep TAFS VFR with mostly clear skies through the period. .OUTLOOK...Non-VFR possible Saturday morning in patchy fog and Sunday night with showers/thunderstorms possible. && .MARINE... An easterly flow 10 to 15 knots will remain over the lake tonight shifting to a southeasterly by early Thursday morning. There may be a slight increase in water levels on the western end of the basin tonight but not expected to reach levels to cause any flooding. Generally 1 to 2 feet waves are expected in the near shore waters with 2 to 4 feet expected in the open waters tonight. With an offshore and southerly flow expected on Thursday, waves will generally be around 1 foot. Light southerly flow over the lake will continue through the end of the week. A stronger low pressure system will develop across the upper Great Lakes region by this weekend, with south to southwest winds increasing 10 to 20 knots Saturday afternoon and increase up to 25 knots by Sunday morning and afternoon. We may need Small Craft Advisories sometime later this weekend. && .CLE WATCHES/WARNINGS/ADVISORIES... OH...None. PA...None. MARINE...None. && $$ SYNOPSIS...TK NEAR TERM...Jaszka/TK SHORT TERM...Griffin LONG TERM...Griffin AVIATION...TK MARINE...Griffin