500 FXUS61 KCLE 130209 AFDCLE Area Forecast Discussion National Weather Service Cleveland OH 1009 PM EDT Thu Jun 12 2025 .SYNOPSIS... A cold front will move south through the area today and stall across northern Ohio Friday night into the weekend, lingering into Sunday. Weak high pressure may briefly build south across the Great Lakes by early next week. && .NEAR TERM /THROUGH FRIDAY NIGHT/... 9:30 PM Update... PoPs and temps look okay for overnight. Virga is developing aloft in response to warm/moist advection and isentropic ascent as the closed low/vort max lifts out of the Mid Mississippi Valley and interacts with the quasi-stationary front. Dry low- levels should keep everyone dry overnight. Uncertainty increases for Friday in terms of timing showers and thunderstorms. The HREF members are in poor agreement in timing the shower/storm development from south to north, mainly due to overall weak forcing other than the boundary, moisture advection, and diurnal heating. Given the uncertainty, see no reason to change Friday`s PoPs at this time, but coverage may end up needing to increase earlier in the day 6:30 PM Update... The forecast remains on track for this evening with no changes needed. The weak cold frontal boundary continues to sag southward and is showing up clearly on regional radar mosaics as a thin line of light returns from about southern Mahoning to northern Marion Counties. Latest mesoanalysis shows only 500-1000 joules of MLCAPE along with quite a bit of CIN along the boundary, so chances for any pop up convection are dwindling. Will need to wait for the deeper moisture from the Mid Mississippi Valley to start to arrive late tonight and Friday, otherwise, dry conditions should prevail. Original Discussion... Awaiting a more consistent push of low/mid level moisture into the region to accompany the cold front pushing southward through northern Ohio. It will eventually become stationary just south of the CWA later this evening into tonight before gradually drifting back northward into Friday. Meanwhile, a 700mb trough axis works into the region tonight from the southwest into early Friday, and this will become the trigger for isolated to scattered showers forming generally after 12Z. The stationary front, back into the CWA, will become more of a focus for convergence and convective initiation with hints of f-gen increasing after 18Z Friday. Another couple of rounds of PVA aloft ripple through late Friday into Friday night. The overall messaging for the sensible weather is POPs on the increase through Friday, coming through in waves into Friday night as the pattern becomes decidedly unsettled as we head into the weekend. Temperatures for Friday will continue to be on the cooler side with primarily 70s north of the boundary and lakeshore zones exposed to onshore winds. Further south, lower 80s are still in play despite the cloudier/wetter conditions. && .SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/... A quasi-zonal pattern aloft will prevail over the region this weekend with the potential for multiple short wave troughs to advect east along it. The first shortwave centered over the Missouri Valley will push east across the Ohio River Valley late Saturday into Sunday. Energy ahead of this shortwave, along with a nearly stationary boundary lingering across Ohio, will prolong the potential for showers and thunderstorms through the entire short term period. The potential for stronger storms with heavy rain will be dependent on the position of the aforementioned boundary, with the best instability south of the boundary. As a result, opted to keep highest chance of PoPs and storms to areas along and south of US-30. On Saturday night, models suggest an associated weak surface low moving across southern Ohio, allowing for a brief period where the boundary shifts south and diminishes rain chances that night. However, by Sunday the boundary ebbs back north and chances of precipitation once again increase. Primary concern this weekend is how much rainfall the area will actually see and the consequential flooding that may occur. Current modeled soundings suggest a warm cloud layer climbing to near 12kft with PWAT values between 1.75-2 inches, which is nearly 90% over the climatological normal. In addition, parallel flow to the boundary at times may lead to training convection in areas. The only component which would aid in enhancing the heavy rainfall potential is a notable LLJ. The updated forecast has a total QPF of 0.7-1" across southern counties, with northern counties receiving notably less with 0.3-0.5 inches. Given the prolonged rainfall, possible flooding is possible in low lying areas, along rivers and creeks, and in urban areas. To highlight the concern, WPC maintains a Day 3 Marginal ERO across the entire area. Saturday highs will be cool, only climbing into the low to upper 70s. Sunday will warm a bit with highs climbing into the upper 70s to low 80s in most areas. Overnight lows will remain mild in the 60s. && .LONG TERM /MONDAY THROUGH THURSDAY/... Long range guidance continues to favor a quasi-zonal flow over the Great Lakes region with the potential for additional shortwaves to advect east along it. These shortwaves will likely present additional chances for showers, although the timing of the shortwaves diverges so confidence is low as to when the best chance of showers will be. Opted to keep chance PoPs for much of Monday through Wednesday. By Wednesday night, it looks like a weak upper level trough will move across the area with associated boundaries at the surface, likely increasing PoPs late Wednesday into Thursday. Still opted to cap potential at slights, but will continue to monitor model guidance and overall trends in the days to come. Highs through the period should gradually warm from the upper 70s to low 80s on Monday into the low to mid 80s on Thursday. Overnight lows look to remain mild in the 60s. && .AVIATION /00Z Friday THROUGH Tuesday/... VFR will prevail through the TAF cycle as a weak cold front that is currently approaching the US 30 corridor becomes quasi- stationary across the region. Moisture increasing from the Mid Mississippi Valley will eventually bring scattered showers and perhaps a few thunderstorms as it interacts with the front Friday, with the best chances being in the mid to late afternoon south of the lakeshore, but expect cigs and visibilities to primarily stay VFR outside of any locally heavier downpours. Put VCSH wording in the TAFs for now since forcing will be minimal other than the boundary, daytime heating, and increasing moisture, but there could be a more defined period of greater coverage in future updates. Winds will generally be N to NE at 5-10 knots tonight and Friday, but the frontal boundary wavering back and forth slightly could bring S to SE winds for a few hours Friday in southern areas near KMFD, KCAK, and KYNG. Outlook...Non-VFR possible in scattered showers and thunderstorms Friday night, becoming more likely on Saturday in widespread showers and thunderstorms, lingering through Sunday. Non-VFR possible again in scattered showers and thunderstorms on Monday afternoon and evening. && .MARINE... A weak cold front has shift just south of the lakeshore this afternoon, allowing for northeast winds of 5-10 knots to develop across Lake Erie. Locally higher winds up to 15 knots will be possible across the western basin, but waves should remain 1-3 feet. This boundary becomes nearly stationary as it tries to push south on Friday. Increased gradient will increase winds to 10-15 knots, possible up to 20 knots at times from the northeast. Highest waves should remain in the open waters, but 2 to up to 4 feet are possible across the western and parts of the central basin on Friday. Will continue to monitor wind trends in the upcoming model updates, but for now not planning to issue a Small Craft given the extremely marginal conditions. Northeast winds will persist into early next week, although weakening to 5-10 knots as the aforementioned boundary shifts a bit closer to southern Ohio. Winds will possibly gain a south-southwest component at 5-10 knots by Tuesday of next week as models suggest a warm front pushing north across the lake, however there is little confidence in the forecast that far out given the weak overall flow and model divergence. && .CLE WATCHES/WARNINGS/ADVISORIES... OH...None. PA...None. MARINE...None. && $$ SYNOPSIS...26 NEAR TERM...Garuckas/26 SHORT TERM...04 LONG TERM...04 AVIATION...Garuckas MARINE...04