Area Forecast Discussion
Issued by NWS Cleveland, OH
Issued by NWS Cleveland, OH
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087 FXUS61 KCLE 251354 AFDCLE Area Forecast Discussion National Weather Service Cleveland OH 954 AM EDT Tue Jun 25 2024 .SYNOPSIS... Low pressure will continue to move east across the northern Great Lakes region, moving a warm front north today followed by a cold front Wednesday. High pressure returns for Thursday and Friday before another low pressure impacts the region this weekend. && .NEAR TERM /THROUGH WEDNESDAY/... 930 AM Update... Minor adjustments to pops and temperatures for the rest of the day, as ongoing MCS has now worked southeast into the Toledo metro area. Low confidence forecast with respect to the evolution of this MCS, as most hi-res solutions are not resolving ongoing activity well. Radar/sat and lightning trends suggest relative persistence/slight downtrend in intensity as the eastward progressing portion of the convection displaces away from the best instability. Some uncertainty with the eastward advection of instability over the next several hours, but think that there should be enough that builds into the far western portion of the area for at least maintenance of the intensity of the storms over the next 2-3 hours, with perhaps a slight uptick in intensity. Right now, storms are producing 35-40 kts winds so things remain sub-severe as of right now. Will continue to monitor evolution of the line over the next 2 hours, with no changes planned for the current severe thunderstorm watch through the 12 PM expiration time. 630 AM Update... The MCS discussed in the previous discussion is currently impacting central Michigan and is expected to continue to push south-southeast towards the area. Satellite imagery suggests that this complex is not weakening much and looking at radar there is now segments bowing with strong winds associated with it. Low level moisture and general buoyancy across the area are weaker than to the west, which suggests that the MCS would continue to decay in the area. Confidence is growing that NW OH and the western basin of Lake Erie will be impacted from this decaying system, posing both a damaging wind and heavy rainfall threat this morning. As a result, a Severe Thunderstorm Watch has been issued for NW OH counties and portions of Lake Erie until 12PM EDT. The best timing for strong to severe storms should be between 8AM - 12PM EDT. This is the time to get prepared and secure lose objects outside. Stay tune for any further updates and make sure to have a way to receive warnings. Original Discussion... To start off, this forecast is extremely tricky given the upstream MCS currently ongoing and how this will continue to evolve as it tracks south-southeast towards the area. Hi-res models diverge quite a bit in the handling of this system and there are multiple potential outcomes that can impact the area. The first is that the MCS continues to decay, reaching the northwest periphery of the area near 15Z and resulting in locally gusty winds and heavy rainfall keeping overall impacts fairly minor. The other potential outcome will be that the strength of the MCS maintains and surges south across Lake Erie, impacts a larger portion of the area with strong winds, heavy rain, and isolated hail. There are many factors that will determine how this evolves, including how much instability will ramp up ahead of the MCS and more importantly if that will be enough to break the cap. High EMLs and steep mid-level lapse rates may be able to continue the decaying trend of the MCS, but again if the instability ramps up quick ahead of it then that may be enough to generate more surface based storms and increase the potential for damaging wind gusts. As this initial round of showers pushes south and continues to decay, a warm front will move across the area late afternoon/early evening, resulting in an increase of WAA and moisture across the area. It is important to note that due to the models slowing the progression of the warm front east, high temperatures for today are not only forecast to climb into the low to mid 80s. There remains a lot of uncertainty in any additional convection this afternoon and into the overnight hour, specifically with uncertainty in how well the atmosphere will recover after this mornings convection. Given the increasing moisture and diurnally driven instability, opted to maintain a chance of PoPs this afternoon into the evening ahead of an approaching cold front. Temperatures tonight will drop into the upper 60s to low 70s. To account for the potential of severe weather today and tonight, SPC and WPC has placed much of the area in a Day 1 Marginal Risk for severe weather and excessive rainfall. Primary concerns will be strong, damaging winds and localized flooding. Late tonight and on Wednesday, a cold front associated with the aforementioned low pressure will begin to move east across the area. With good synoptic support and strong isentropic lift, expect another round of showers and thunderstorms to impact the area for Wednesday. To account for this severe potential, SPC & WPC has placed much of the area in a Day 2 Marginal Risk for severe weather and excessive rainfall. The primary hazard with these storms will be damaging winds and efficient, heavy rainfall which may result in localized flooding. High temperatures on Wednesday will climb into the mid to upper 70s. Again, it is important to note that this entire forecast is highly dependent on the evolution of the ongoing MCS over the upper Midwest and is valid to change/be adjusted in the coming updates as models begin to handle the evolving complex better. && .SHORT TERM /WEDNESDAY NIGHT THROUGH FRIDAY NIGHT/... The short term forecast period will be fairly quiet, especially compared to the days before and day after the period. A cold front will be exiting the forecast area on Wednesday night and have quickly fading PoPs with clearing skies and falling temperatures into the lower 60s. High pressure will build in behind the cold front for Thursday and Thursday night and temperatures will be cooler than normal in the 70s during the day. Clear conditions and a decoupling atmosphere should allow for temperatures to fall considerably on Thursday night into the 50s with some upper 40s here and there, mainly NE OH and NW PA. The surface high pressure will shift east for Friday and return flow back into the region will allow for temperatures to climb back into the 80s. The return flow will also allow for better moisture to return with 60 degree dew points returning by evening. Shower and thunderstorm activity upstream will start to enter the region on Friday night. While the atmosphere will have more moisture to work with by Friday night, a stabilizing air mass with nightfall will allow for just some scattered convection with minimal concerns. && .LONG TERM /SATURDAY THROUGH MONDAY/... A cold front with a supporting upper trough will move through the region on Saturday and allow for widespread chances of showers and thunderstorms. The intensity of convection will be based mainly on the timing, which at this point could be during the afternoon hours, so storms could have some punch with them. Temperatures before any showers and storms on Saturday could rise into the upper 80s and perhaps give 90 degrees a brief tap, if the system slows up a bit. The trend for Sunday into Monday will be dry with high pressure building back into the region and temperatures will remain slightly below normal with the cooler air mass in place behind the cold front. && .AVIATION /12Z Tuesday THROUGH Saturday/... Pleasant aviation conditions this morning with winds from the south at 5-10 knots will become less desirable beginning mid to late morning, especially for KTOL. An MCS continues to trek across central Michigan this morning and is expected to impact NW OH between 13-16Z with strong, damaging wind gusts and heavy rainfall the primary concern. Conditions in these storms will quickly diminish to IFR, but possibly MVFR, as heavy rain reduces visibilities at KFDY and KTOL. The remainder of the terminals will likely see precipitation onset late this morning/early afternoon, although impacts should remain minimal for these terminals. As the environment tries to recover this afternoon, there is an additional threat for scattered showers and thunderstorms across the area, but confidence in timing and location is fairly low at this point as it is highly dependent on what happens over the next couple hours. Opted to handle the uncertainty with VCTS at most terminals, but cannot rule out MVFR conditions in any terminals that get storms. By Wednesday morning, a cold front will move towards the area, bringing widespread showers and thunderstorms and lowering ceilings to at least MVFR conditions. Quite a messy aviation day going forward, but storms should not be widespread until late tonight/early Wednesday morning. Winds from the southwest will quickly ramp up this morning to 12-16 knots, gusting up to 20-25 knots through the afternoon hours. After sunset, winds will weaken to 5-10 knots and remain from the southwest through the end of the period. Outlook...Non-VFR possible in showers and thunderstorms today and Wednesday. Non-VFR possible again in showers and thunderstorms on Saturday. && .MARINE... High pressure will continue to the east of the region today and return flow with south to southwest winds behind a warm front will persist across the lake. The pressure gradient and surface winds will increase later this morning and into the afternoon as a storm complex enters from the northwest and will allow for winds of 20-25 kt for a 6-8 hour period. Believe the 20 kt sustained mark gets to about Cleveland and have extended the Small Craft Advisory east. The window for stronger winds is later than previously forecasted and have a later end time to encapsulate the entire event. Showers and storms will be possible across the basin today and tonight and convective marine headlines will be possible. A cold front will cross the lake on Wednesday and flow will become northwest. The pressure gradient over the lake does not look impressive enough to have substantial northwest flow to allow for a great increase in waves. Flow will become lighter and northerly with high pressure on Thursday. Southeast flow returns to the lake on Friday with a warm front lifting across the region, as high pressure moves east. A cold front will cross the lake on Saturday. Southwest flow will increase ahead of the feature and could approach the need for a headline. && .CLE WATCHES/WARNINGS/ADVISORIES... OH...None. PA...None. NY...None. MARINE...Small Craft Advisory until 7 PM EDT this evening for LEZ142>146. && $$ SYNOPSIS...Campbell/Greenawalt NEAR TERM...Campbell SHORT TERM...Sefcovic LONG TERM...Sefcovic AVIATION...Campbell MARINE...Sefcovic