Area Forecast Discussion
Issued by NWS Cleveland, OH
Issued by NWS Cleveland, OH
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731 FXUS61 KCLE 251737 AFDCLE Area Forecast Discussion National Weather Service Cleveland OH 137 PM EDT Wed Sep 25 2024 .SYNOPSIS... A weak cold front will slowly move through the area today. High pressure will build from the northwest for Thursday. The remnant low pressure of Helene will enter the Ohio Valley for Friday and Saturday. && .NEAR TERM /THROUGH THURSDAY/... 1230 PM Update... Another line of showers has begun to develop just ahead of the cold front near the I71 corridor. Locally heavy rainfall is possible with this line along with a couple rumbles of thunder, but no severe weather is expected due to limited mesoscale support. These showers will slowly move east through the evening, allowing for conditions to dry out behind the front. Except cloudy conditions to persist with few breaks of sunshine possible across western counties. 930 AM Update... This morning, showers and a few rumbles of thunder have worked their way into the far southeastern tier of counties, extending from Knox to Mahoning Counties with additional showers in Crawford County PA. This will be the primary focus of shower activity today, although cannot rule out some showers a bit further north. Given the marginal mesoscale environment, not expecting anything severe today, but will monitor radar trends for anything rogue. With this update, the only change really needed was adjustments to temperatures as current observations suggest a bit warmer start to the day than previously forecast. No other changes were needed with this update. 630 AM Update... Some shower activity has been in and out of NE OH and NW PA this morning and will continue through today ahead of a cold front. Have added PoPs a touch further west than the previous forecast with the front remaining sluggish in NW Ohio. Previous Discussion... A cold front across Northwest Ohio this morning will slowly move east across the forecast area today. Ahead of the front, additional showers and some embedded thunder will be possible with help of the main trough entering the Great Lakes region, decent moisture in the region, and even a touch of instability. With the energy of the upper trough splitting between a trough to the northeast and a cut off upper low over the lower Ohio Valley, the surface front may not reach the eastern portion of the forecast area until tonight and have PoPs for much of the day to reflect that any shower chances are possible until the front passes to east. High pressure will build from the northwest for Thursday and this feature will allow for dry conditions to return to the area. Temperatures through the period will run close to normal. && .SHORT TERM /THURSDAY NIGHT THROUGH SATURDAY NIGHT/... The remnants of Helene will drift inland and effectively be absorbed into an upper low over the Ohio/Tennessee valleys late this week into the early part of the weekend. High pressure will likely maintain control over the local area through Thursday night, but PoPs begin to increase as early as Friday morning as moisture begins to stream north into the Ohio Valley as the surface low moves northwest into the the vicinity of the Illinois/Missouri/Kentucky borders. From there, the low will churn to the southwest of the local area throughout the weekend and periodic showers with low-end chances of thunderstorms are possible Friday afternoon through Saturday night. There`s still quite a bit to iron out with the progression of Helene as it prepares to make landfall and moves inland in the upcoming days, so opted to maintain consistency and cap PoPs at slight chance to chance. Will continue to refine PoPs as the scenario becomes a bit more clear. If a rainier forecast does pan out, dry air may wrap into the area so it may not be a washout. Precip coverage will probably be highest during peak diurnal heating. The pressure gradient will tighten considerably Friday as the high struggles to maintain control over the region, resulting in breezy northeast winds to 25 to 35 mph downwind from Lake Erie. Highs will generally be in the 70s throughout the short term period but a few spots may touch 80 degrees in southern zones Saturday. With that being said, the temperature forecast will likely change with the precipitation forecast; increased cloud cover and rain chances may result in cooler highs. Expect overnight lows in the upper 50s to lower 60s each night. && .LONG TERM /SUNDAY THROUGH TUESDAY/... The aforementioned upper low will finally begin to gradually progress east across the Ohio Valley during the start of the long term period and periodic showers and thunderstorms remain possible through the remainder of the weekend. There`s still some uncertainty in how quickly the low exits and whether or not a ridge builds over the region so maintained PoPs for the time being. By Tuesday afternoon, an upper trough and surface cold front may approach from the northeast, resulting in additional chances of showers and thunderstorms. Temperatures will be a few degrees above normal Sunday and Monday, but a cooler weather pattern may begin to unfold as temperatures fall to near normal values Tuesday. && .AVIATION /18Z Wednesday THROUGH Monday/... Quiet a mix bag of conditions across the area this afternoon as a cold front slowly meanders east. Behind the boundary/west of I71, ceilings continue to bounce between high end MVFR/low end VFR with winds from the west-northwest at 5-10 knots. These conditions will likely continue over the next couple hours. By evening, most western terminals, including KTOL, KFDY, and KMFD should rebound to VFR through the first half of tonight. For areas along and east of I71, conditions continue to range from IFR to VFR due to a variety of reasons. First off, there are generally lower ceilings ahead of the cold front, generally ranging from 800-1500 ft, but with some scattering in the cloud deck. The second reason is due to ongoing precipitation just ahead of the boundary extending from eastern Cuyahoga County, southwest to Knox County. Terminals that are impacted by this line will likely have visibilities reduced to MVFR/IFR visibilities. In addition, winds will persist from the southwest at 5-10 knots through this evening. In general, this group of terminals are not likely to rebound to VFR until tomorrow. By tonight, winds will become light and variable across the area. For far western terminals, conditions should remain VFR. Elsewhere, especially in areas where it rains today, there is a potential for fog develop that will reduce conditions to MVFR and IFR in spots. The highest confidence in conditions being reduced to IFR visibilities is at KCAK and KYNG where visibilities could drop below 2SM with ceilings lowering below 1kft. KCLE, KMFD, and KERI may see some patchy fog, but with lower confidence opted to only drop them to MVFR with this update. By the end of this period, winds will begin to increase to 5-10 knots from the northeast. Outlook...Strong northeast winds are expected across the region on Friday. Non-VFR may return in showers and thunderstorms this weekend. && .MARINE... A Small Craft Advisory remains in effect from Conneaut OH to Ripley NY until 12Z/8 AM this morning, but southeasterly winds are already beginning to diminish. Winds will diminish to 15 knots or less and shift to the west/northwest as a cold front crosses the lake this afternoon through tonight. By Thursday morning, flow will become northeasterly as high pressure builds over Lake Erie with winds strengthening to 10 to 20 knots as the remnants of Helene move inland on Thursday night. Winds will peak at 20 to 25 knots Friday afternoon into Friday evening, although some guidance members are hinting at potential for winds reaching as high as 30 knots. Small Craft Advisories will most likely be issued for Friday morning through late Friday night or Saturday morning. Northeast winds diminish to to 10 to 15 knots with winds near 20 knots likely in the open waters of the central basin so it will probably remain choppy even after headlines end. East/northeast winds 10 to 15 knots will persist through Sunday. && .CLE WATCHES/WARNINGS/ADVISORIES... OH...None. PA...None. MARINE...None. && $$ SYNOPSIS...Sefcovic NEAR TERM...Campbell/Sefcovic SHORT TERM...Maines LONG TERM...Maines AVIATION...Campbell MARINE...Maines