OHweather

Hopefully your power is back on by now! Sorry to hear about the mess on your property but it's good nothing hit your house. That red elliptical area were winds blowing east with the gust front. The storm was pretty complex...there were east-southeast winds ahead of the squall line (which appeared as inbounds on the radar), a small area of west-northwest winds with the gust front (the red outbounds on velocity), and then a strong surge of northerly winds with a rear inflow jet behind the squall line (which showed up as green inbounds on velocity on the CLE radar). There also was a book-end vortex that came onshore just northeast of downtown Cleveland and tracked roughly east into southern Lake/northern Geauga, which augmented that rear inflow jet. The very strong straight line winds that impacted much of NE Cuyahoga, western Lake, and northwestern Geauga happened as the rear inflow jet wrapped in behind the bookend vortex and the tornado in Chesterland happened in association with that mesovortex. I think what made this one so impactful was the area hit. Out of the 4 tornadoes, two of them had rather long tracks through very populated areas in the heart of suburban Cleveland. Outside of the tornadoes, there were widespread 60-70 MPH winds from Lorain County into the Cleveland area which caused scattered tree/power-line damage outside the tornado tracks. Into the east side gusts increased to 70-90 MPH, locally up to 100 MPH in northeast Cuyahoga, western Lake, and northwestern Geauga. We actually surveyed that extensive area and only found the one tornado track in Chesterland, along with widespread, significant tree damage caused by straight-line winds. That hit a fairly densely populated area in the eastern suburbs. From there, there was scattered tree damage well to the south and southwest of Cleveland including Medina, Youngstown and the Akron/Canton area which added some impact to the power grid...and the rest of northeast Ohio (Ashtabula, Portage, Trumbull and Mahoning) had scattered downed trees with pockets of more intense damage...the bow echo (and associated bookend vortex and rear inflow jet) continued across southern and eastern Geauga, northern and eastern Portage, southern Ashtabula and northern Trumbull and there were more localized pockets of significant tree damage (not quite to the level of the east side of Cleveland but there were probably pockets of 80 MPH wind all the way across to the PA border embedded within widespread 60+ MPH gusts). That added up to a relatively localized but significant impact in a very densely populated area surrounded by a large area of less significant damage which added to the power outages. I think last August's derecho and tornadoes (August 24th-25th overnight) would have been more substantial if it hit in the afternoon or evening and not at midnight. The tornadoes with that event were more significant than with this event and the rear inflow jet aloft on radar was larger and stronger. However (and fortunately), the straight-line winds didn't mix down as effectively at midnight when that came through last August...the damage ended up being significant but streaky and relatively scattered with little damage in between. At peak heating, the straight-line gusts with that even would have been much more widespread and perhaps slightly more significant on the top end, so I think the tree damage and power outages would've been more significant that this most recent event. The June 2022 derecho, which crushed portions of north central and east central Ohio, produced a nasty swath of 60-80+ MPH type winds starting in northern IN and northwest OH with pockets of 100-120 MPH in parts of southern Wayne, Holmes, and Tuscarawas Counties. That would have been worse than this if it hit the Cleveland area. Even the November 2017 macroburst (which was associated with a similar bookend vortex and rear inflow jet as this event) across the Cleveland southern suburbs may have rivaled this event's power outage numbers if it occurred more directly over the Cleveland area and happened when leaves were still on the threes. So my impression is that I'm relatively impressed by this event and it certainly had a high impact, but we've narrowly avoided worse outcomes in the metro area for one reason or another in recent years. So while it is "historic" by a power outage perspective for the Illuminating Company, I do not think it's anywhere near unprecedented for what storms can do in the northern half of Ohio. What allowed this system to produce higher end severe was a combination of a seasonally strong front and wave of low pressure riding along it, which added lift and enhanced low-level shear, a very moist airmass which allowed for good instability to develop, even slightly north of the front in stronger shear, an incoming shortwave which added large-scale lift and supported quick upscale growth of thunderstorms, and fairly strong winds aloft which provided enough shear for organized/rotating updrafts and mesovortex development within squall lines, which supports stronger bow echoes and QLCS (squall line) tornadoes. It was actually quite a favorable set-up for northern Ohio standards.

There was a small embedded tornado track from far southern Lake County into the northern portion of Chesterland, but otherwise it seems like most of the damage from the east side into Lake and Geauga was due to a very strong rear inflow jet punching into the bowing line of storms.

That was certainly the event of the year around here. More than half of Lake and Geauga are still without power, and the outages have barely come down since last evening.

More than half of Lake and Geauga Counties are still without power in NE Ohio, with outage numbers barely budging in Cuyahoga County since last evening (down slightly to a bit over 200k outages/38% out in the county). Impressive event with what will likely be a handful of confirmed tornadoes and widespread straight-line wind damage.

I do think that if a tornadic supercell played out over NW OH that the lake influence may have still had in effect on it as it approached the lake, though in this case I think other factors just prevented a tornadic supercell altogether. Fully agree with this. I do think that as you suggested, the CAPE gradient suggests some sort of boundary (often a front or outflow, sometimes differential heating) with winds often more backed along and on the cool side of boundaries...with boundaries also providing for low-level convergence/lift which can aid in getting stronger updrafts. Whatever the reason(s), I've heard the words "it's always on the gradient" uttered more than a few times in operational meteorological settings. Also agree that the storms in Michigan on Tuesday benefited from stronger forcing, and per this RAP sounding (likely not perfect but hopefully close) low-mid level lapse rates were steeper than the NW OH sounding. Can also note some very large hail analogs on the bottom right, with a higher % of the loose matches being significant than in the NW OH sounding. Surface winds along and on the cool side of the warm front were SE, which would increase SRH from what this sounding shows:

On that sounding the two main negatives that stand out to me are the poor low to mid-level lapse rates leading to a tall/skinny CAPE profile along with weak storm relative winds and a messy hodograph in the 2-4km layer. Here's essentially the same sounding from Pivotal with height in km placed on the hodograph, helps visualize the lack of shear in the 2-3km layer (2 and 3km are almost on top of each other): I'm guessing that between the skinny low-mid level CAPE profile and relatively weak storm relative winds in the mid-levels there might have been more of a struggle to maintain strong/deep updrafts around NW OH than you'd otherwise expect with over 1500 J/KG of MLCAPE, 60+ knots of effective shear and 200-300 m2/s2 of effective SRH. You can sometimes get more severe wx out of a lesser amount of CAPE that's all focused below 400mb with a thicker CAPE profile than with a greater amount of CAPE but with a skinner CAPE profile through a deeper layer. The other thing that stood out to me in northwest / north central OH was just where storms initially developed. The storms that initially developed from east-central IL into central IN ended up being the main show in the northern OH Valley and fired on the nose of the deeper instability advecting in from the southwest. The mid-level flow was southwesterly, so these storms developed upstream of northwest OH. I am guessing that as these storms grew upscale that some subsidence and warming in the mid-levels occurred. I think that's why the cell that went tornado warned east of Fort Wayne into Northwest OH did OK for a bit but then started weakening as activity to the south/southwest continued to grow upscale. It's possible this led to warmer mid-levels and an even worse CAPE profile over NW OH in the evening than the RAP sounding suggested. The cells that developed over NE IL/far NW IN and tracked into MI were beneath the divergent left-exit quadrant of a jet streak rounding the base of a negatively tilted trough so had the benefit of stronger forcing and were more separated form the Ohio Valley storms. And as we all know those storms certainly produced. It's been a frustrating spring for convective forecasting in the northern 1/3 to 1/2 of OH. Every setup has had shear but most setups, outside of March 14th, have had relatively marginal thermodynamics. If you get sustained deep convection you'll get tornadoes in these set ups given the shear, but if you don't get that because there's just not quite enough instability everyone thinks we're nuts for predicting a risk of tornadoes. March 14th and April 17th produced (though March 14th had great thermos, the main uncertainty was how far northeast the instability would get behind earlier day rain). A few other of these high shear, marginal instability setups (April 2nd, April 11th, yesterday) did not produce locally.

Was sweating the cirrus here in Cleveland but it was thin enough that you could see through them enough to see all the cool stuff. Had the 360 degree sunset effect on the horizons with the cirrus adding some color. Briefly saw a couple of planets. Bats came out, streetlights came on. It was about as dark as it is immediately when the sun sets I would say. Seeing the corona and some solar flares was awesome. The difference in the amount of light between a 99% eclipse and totality was impressive. As soon as even the smallest bit of the sun came out from behind the moon the light noticeably increased. Overall I'd say it exceeded my expectations.

A few comments on this event, focused on the Ohio Valley... 1. An enhanced risk (for winds and possibly tornadoes too, pending surveys) was warranted across the Ohio Valley. From a verification stand point I do not think the Moderate Risk panned out anywhere (especially for tornadoes). The northern extent of the threat was significantly less than outlooked. 2. The main reasons this busted were due to repeated rounds of convection that were ongoing both along and north of the warm front and in parts of the warm sector from last night through all of today. This chewed up the EML and limited destabilization farther north and east. You can tell that convection that tried firing along the cold front and a pre-frontal trough in the late afternoon and early evening was struggling due to limited spacing between it and pre-frontal convection that was already ongoing. The storm mode was also messy, probably because junk developed quickly in the warm sector and it was impossible to come back from that. 3. I was concerned about some of the uncertainty and was surprised to see the Day 2 moderate (at least as far north/east as it was). I felt the 12z HRRR and NAM on Monday did depict outbreak scenarios and that the outlook needed to ramp up from the morning outlook on Monday...but there were enough CAMs with less exciting solutions for multiple reasons that the moderate risk was certainly an aggressive forecast. However, I thought something significant still had a decent chance to play out somewhere (likely in the Ohio Valley). With such a large warm sector, deepening low pressure and insane wind fields, it felt like it would be hard to avoid somewhere destabilizing and having a supercell or two take advantage of that locally more favorable environment. It's possible there were a couple of strong tornadoes today and there were probably more than a few weak tornadoes, including with the morning QLCS into WV. However, I would say I definitely expected more to happen even if certain parts of the threat/outlook didn't sit great with me. 4. The Tennessee Valley generally busted too, due to junky convection firing too early in the warm sector down there. This whole event was cursed apparently. 5. Given a fairly legitimate potential for a significant tornado or two somewhere this threat certainly required stronger than normal messaging. However, I feel like the way severe weather outlooks are often presented does not always do a good job of advertising uncertainty or bust potential. It's just "strong to severe storms possible between 3 and 8 PM, here's the outlook showing a slight risk". While I saw a couple of people in OH on Monday mention potential for ongoing clouds/rain earlier in the day to mess with the threat that generally was not mentioned until today when it was in fact raining. Instead, the messaging was focused on what is pretty much an unprecedented severe weather outlook, a Day 2 moderate risk driven by tornadoes. That was messaged as a very rare outlook for Ohio (which is not incorrect) and took on a life of its own. The event couldn't bust without meteorologists looking bad, so of course it busted for most of OH. Overall, severe weather risks that have a ceiling of a regional tornado outbreak but legitimate bust potential are a challenge to message and there's room to get better at it.

The stuff currently developing from central IN into KY (and anything that fires immediately ahead of it) will be “the show”. We’ll see what the show ends up being. Airmass recovery attempting to occur ahead of that activity but it’s a short window to do it. The low is deepening so wind fields will be extremely robust. We’ll find out quite a bit about if much will happen in the next few hours.

0z HREF probability for STP >3 and member updraft helicity (supercell) tracks. Mod-high probabilities for STP >3 from central OH-IN through parts of KY & TN surrounded by lower probabilities, with sct'd individual member supercell tracks. The setup has a high ceiling, but: Neighborhood probabilities for supercell tracks are moderately high in the Ohio Valley (best environment), high in the Tennessee Valley (slightly lower STP >3 probs), and low-moderate north into IN/OH/W PA (lower confidence in STP >3 farther north). There is uncertainty: For instance, the 0z HRRR has extensive elevated convection in the Ohio Valley that continues through midday, with warm sector convection becoming widespread by 18z. This would be some sort of (potentially more middling, though with conditional risk for strong tornadoes still) OH/TN Valley tornado threat but with more limited northward extent into IN/OH. On the other hand the NAM clears the morning Ohio Valley convection slightly quicker and also delays warm sector initiation longer into the afternoon. This would lead to a likely more significant tornado threat in the Ohio Valley that extends into much more of Ohio. The NSSL WRF is a bit in between. It clears the Ohio Valley morning convection a bit quicker but also has a fairly busy warm sector by mid-afternoon. Verbatim it still would be a somewhat messy Ohio/Tennessee Valley evolution but there would be a tornado risk, especially in the Ohio Valley where there could still be a conditional significant tornado risk with this sort of evolution. In terms of northern extent, there'd be at least some threat for most of Ohio along and south of the warm front. And finally, the ARW with similarities to the NSSL, clearing the morning convection fairly early and developing warm sector convection a bit quickly (tho not as fast as the HRRR), with a middle ground solution in terms of overall tornado risk and northward extent into OH: Some subtle adjustments can probably already be justified for the initial day 1 outlook at 2 AM eastern...however, I doubt there will be anything wholesale until later in the morning when it's much more obvious how the ongoing convection is behaving. 3z HRRR would probably play out somewhat close to the 0z NSSL WRF if it ran out further...

I'd lean more towards the convection eroding the EML than the other way around.

Yes, my take on the 0z HRRR was that it being more expansive morning MCS in the Ohio Valley, with elevated convection continuing to fire overtop its cold pool through the early afternoon and convection firing in the warm sector and becoming widespread by mid-afternoon, were why it didn't really destabilize north of southern OH. We may have a better lean on how that will play out within the next few hours. Yes, I assume there was a ton of internal discussion about the outlook. I was off today so can not confirm or deny. It is a tough spot, and the initial day 2 pulling things farther south really made things worse. I do think that the setup can support one or two long-tracked, violent tornadoes, so based on that I can not fault the day 2 moderate risk. If you expect long tracked, violent tornadoes that's more than an enhanced risk. I could perhaps quibble with it being placed so far northeast, but I do think there is a conditional threat in at least the entire moderate and enhanced risk areas so I can't totally fault it either. Some of the messaging I've seen regarding this threat is some of the strongest I've ever seen around here...there is something to be said about being sure before breaking out the strongest possible messaging. I'm both worried about the higher end of the potential and what that could look like (even if it's just one or two really nasty tornadoes) but am very uncertain on where or if we'll see that pan out.

Considerable uncertainty, largely driven by ongoing/earlier-day convection, is definitely a familiar feeling for the Ohio Valley. There certainly is higher-end tornado potential if a portion of the warm sector is relatively clear and can recover through at least the mid-afternoon, and I feel like that's more likely than not to occur somewhere in the vicinity of central/southern IN, western/southern OH, and perhaps adjacent northern KY. Where exactly that occurs and how large of an area it is are certainly in question. From a messaging perspective this is kind of brutal...I'd consider northern and even central (especially east-central) OH to be on the fringe. If ongoing convection and clouds clear quickly enough there's still a viable scenario where those areas recover enough to have a threat, and given the amount of shear in place that needs to be messaged. However, it's also possible that little happens on that northeastern fringe. We've already gone all-in with a tornado-driven moderate risk, so while I'm personally hoping for (and sort of leaning towards) nothing too noteworthy happening in the Cleveland metro and my immediate vicinity just south of Cleveland, a total whiff in the northern/eastern half of Ohio would be a strike against public trust in the severe wx forecasts.

Some random thoughts based off of the 0z NAM and HRRR...how quickly morning convection exits and allows the warm front to start lifting, along with if convection starts getting pretty widespread in the Ohio Valley by mid-afternoon, which would further limit northward/northeastward moisture return and recovery, are both major sources of uncertainty regarding the northeast extent of the tornado threat. Also, models are still trending slower/west with the low and jet streak. I think the northern/northeastern portion of the higher tornado probs should be trimmed, perhaps notably, and the overall highest tornado probs shifted a bit farther SW. We'll see what the rest of the 0z models show and what the initial day 1 outlook comes up with.

Broyles has gotten better over the years and usually the SPC is pretty good about not whipping around the outlooks too much, but I don’t think anyone was very happy with the initial Day 2 outlook this morning to say the least