562 FXUS61 KCLE 060122 AFDCLE Area Forecast Discussion National Weather Service Cleveland OH 922 PM EDT Tue Oct 5 2021 .SYNOPSIS... High pressure briefly builds south across the area tonight into early Wednesday as the next area of low pressure moves north across the Tennessee Valley on Wednesday into Thursday. This low may linger across the Ohio Valley Friday into Saturday. && .NEAR TERM /THROUGH WEDNESDAY NIGHT/... Only minor changes have been made to the location of the cloud cover as it continues to move southward across the CWA. Changes were made to hourly temperatures to reflect current trends. Latest thinking is that the fog may end up being more of an issue across the central and western CWA as the easterly downslope flow keeps it from developing across the east and southeastern CWA. In any event it should not be as dense as early this morning. Previous Discussion... Generally quiet weather is expected through Wednesday night with high pressure set to remain across the Great Lakes for the rest of today and into Wednesday morning. Some patchy fog may set up across the south and southeast portion of the area late tonight, but it won't be as widespread as this morning, given elevated wind profiles in the boundary layer and at the surface. Wednesday's weather should be quite pleasant with highs in the mid to upper 70s to perhaps even lower 80s. The best chance for any rain showers will be generally west of the I-71 corridor Wednesday afternoon and evening, though confidence isn't too great on coverage given a lack of forcing and fairly dry low-levels. This is partly in due to the departing high pressure Wednesday morning, which will linger across the Northeast and act to stall the next approaching storm system. Cloud cover will increase as we head into the late evening and overnight hours as the low pressure system works its way north across the Tennessee Valley. Lows on Wednesday night will remain warm, moist, and above average, in the low to mid 60s. && .SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/... High pressure at the surface and aloft exits to the north and east through Friday night. Simultaneously, a longwave trough gradually overspreads the OH Valley and Great Lakes from the Lower MO River Valley and vicinity. At the surface, a warm front should drift north- northeastward across our CWA Friday afternoon through Friday night. It will remain unusually warm and humid for early October as a low- level return flow of warm and very moist air from the Gulf of Mexico persists along the backside of the retreating surface high pressure ridge and affects our region. Balmy temperatures persist with overnight lows ranging from the upper 50's to mid 60's and afternoon highs ranging from the mid 70's to 80 degrees. Periods of showers and thunderstorms are possible, especially in the afternoon and early evening of both days, given diurnal destabilization of the boundary layer, and during the warm frontal passage. && .LONG TERM /SATURDAY THROUGH TUESDAY/... At the surface, we should remain along the western periphery of the high pressure ridge and within the impressive low-level return flow of warm and very humid air from the Gulf of Mexico. The aforementioned trough aloft de-amplifies while exiting to the northeast Saturday and Saturday night. By Sunday, ridging aloft should build over our CWA from the southwest and then continue affecting our area through Monday night as the ridge shifts generally eastward. By Tuesday, another trough aloft may overspread our region from the west. Odds favor dry weather through most of the period, but shower and perhaps thunderstorm chances should increase next Tuesday with the aforementioned approaching trough. Unusually warm temperatures persist with daily highs primarily ranging from the mid 70's to about 80F. However, strong low-level WAA and greater sunshine on Sunday may allow highs to soar into the low to mid 80's across most of our CWA. Lows in the upper 50's to mid 60's likely persist. && .AVIATION /00Z Wednesday THROUGH Sunday/... MVFR/IFR conditions will slowly spread southward off of the lake through the evening. Believe all TAF sites will experience these lower clouds through 07Z. The clouds should then slowly lift, maybe erode, near the OH/PA border including NW PA as an east to southeast flow becomes established. This flow should help to minimize the fog threat across the eastern TAF sites. Better chances of lower visibilities seems to be near and west of a KLPR to KMNN line. However dont think it will dip below a mile. MVFR/IFR conditions gradually improve from west to east after 07Z. All locations should return to VFR conditions by early afternoon. Winds remain northeast to east through WEdnesday at 5 to 12 knots. The strongest winds near the the south shore of the lake. Outlook...Non-VFR possible within showers and thunderstorms Thursday and Friday. && .MARINE... High pressure affects Lake Erie through Friday. East-northeasterly to northeasterly winds of 10 to 20 knots and 1 to 3 foot waves, with occasional 4 footers, are expected through tonight. Refrained from issuing a Small Craft Advisory given the marginal forecast conditions. Winds of about 10 to 15 knots out of the northeast through southeast and waves of 1 to 3 feet are then expected Wednesday night through Friday. A warm front should sweep northward over Lake Erie Friday night and shift primarily southeasterly winds of 5 to 15 knots to southerly. Southerly to southeasterly winds of about 10 to 20 knots are then expected this weekend as high pressure regains control. Waves should trend 1 to 3 feet in U.S. waters. && .CLE WATCHES/WARNINGS/ADVISORIES... OH...None. PA...None. MARINE...None. && $$ SYNOPSIS...Kahn/MM NEAR TERM...Kahn/MM SHORT TERM...Jaszka LONG TERM...Jaszka AVIATION...MM MARINE...Jaszka