hlcater

I had time to drive around quite a bit yesterday and traced what was essentially a big X across much of Linn County. From this, two areas of especially intense damage were found. The first being up near Robins/Hiawatha/Midway/Marion, and the second being along US 30 into the SW side of CR and Fairfax. This forest blowdown was near Midway and about half of all trees were snapped, and the ones left had suffered heavy foliage/limb damage. This was not far from the 112mph report, though part of me wonders if the winds that caused damage like that weren't higher? Impressive damage from Marion. Particularly the apartment building that lost roofing. This high tension power line was downed about 2 miles west of Palo. 4 of these were toppled in a row. Another one of those DIs that suggest winds of at least 100mph. The next two pictures are from the US 30 corridor near Atkins. These are from the SW side. The damage here was the most intense I was able to find. Especially the damage to the MAC and surrounding apartments (shown). We were without power for 3 days, having it restored at about 11pm last night. We were one of the first areas to have their power returned yesterday. As of now, many areas of CR(roughly 60%) still have no power and some areas are still blocked due to tree falls and downed lines even 4 days later. This is the worst derecho I have ever experienced and I'm not sure if the scale of destruction from it can be accurately described, especially on the corn crop (as stated already) and will have a lasting impact on Cedar Rapids, both on the surviving trees and in memory. It was like an intense RFD, but lasting 3 times as long and 5 times as wide. Here are two additional albums of pictures. https://imgur.com/a/dvhGA87 https://imgur.com/a/sqSl6Cm

Okay, I've got power and some time to upload/give an account so let's do it. Like I said the morning of, I had been suspicious of derecho potential monday but seeing how my call sunday didnt pan out due to poor convective evolution in the morning, I wasn't gonna bust twice, so I just put a sock in it. Once I saw the storms forming in NE though, I knew it was game on, as that seemed to be the biggest differentiator. If storms didn't initiate/organize in NE, they probably weren't going to at all. With that out of the way, I worked at 3pm so I couldn't afford to go meet the derecho out in the middle of the countryside, so I met it 3-4 miles west of Fairfax. The storm caught me before I was ready and I was expecting the strongest winds right along the gust front but interestingly, my location was such that the strongest winds took awhile to arrive and I distinctly remember thinking "wow, this sucks. 120mph aloft and I'm only gusting to maybe 60mph". Perhaps its best the strongest winds waited, as it gave me time to scout out a nice spot in a corn field where I'd be safe from powerlines/trees. Not shortly after, the core of wind which I estimate consisted of gusts to ~100mph arrived. From that point on, I was just along for the ride. Strongest winds persisted roughly 5-10 minutes, but wind gusts of severe criteria lasted 45 at least. This dash video is the strongest 5-10 minutes of wind. With winds from about 1:30 to 5 minutes being especially intense. Nick Stewart's video is very similar to mine. A farm about half a mile downstream from me suffered heavy tree damage and a grain silo of theirs was tossed/rolled probably 100yds into a field. I made my way towards Fairfax, which had suffered heavy damage, with many trees and powerlines down and one building completely destroyed and its contents strewn downstream. Getting from Fairfax to downtown took an eternity. Most roads were a standstill, and on the stretch of 380 from hwy 30 to H avenue, I counted 8 overturned semis. It took me well over an hour to drive about 10 miles. I worked for the rest of the day(hospital ER) and we were so overwhelmed with the amount of thankfully minor injuries(trees, glass, ceiling collapses, overturned semis, that sort of thing) that we were treating people in the hallways and had to open up overflow areas. The fact the entire city was without power exacerbated the issue. This last pic was from Hiawatha from a family member. I worked the next day as well, so don't have much there. That's the initial experience and pics from the first day, but I'm not done yet .

There were probably tornadoes in the DVN CWA, but when the background winds were similar to what you’d find in a QLCS tor, I have to imagine that’s hard to find.

Clocked in Cedar Rapids. Rode it out in a corn field north of walford where I experienced 100mph wind gusts as the MCV intensified to the north. This is the same axis of damaging wind that came thru Cedar Rapids moving NE. I’ll leave a few pics for now. Worst storm I’ve ever experienced. Still without power and cell signal(1 bar LTE currently). I’ll post more when I can. For now here’s a few. https://imgur.com/a/Ezml1sS

Saw something like this coming last night with the steep lapse rates, big CAPE and 50kt jet nosing in. (Tho I saw something like this coming Sunday too and it never did, due to OFBs and poor destabilization). Well this one’s here, it’s not dying any time soon and I’m ready.

MCS generation parameters are pretty good tomorrow. 5000 CAPE gradient along a warm front oriented favorably towards NW-SE shear vectors, probably 30-35kts of EBWD and a relatively decent LLJ, at least for this time of year and during the day. CAMs disagree wildly on what exactly transpires, but might get a decent storm around here at least.

This summer has been insufferably boring.

TD10 about to waste the best name on the entire 2020 list for a 40mph TS. Sad!

I have been split twice today by thunderstorms.

2020 failing to even produce garden variety thunderstorms and opting for cold stratiform rain. Classic!

look what 2020 has reduced people to this "event" lol

models keying in on the potential for a seasonably robust shortwave to rotate through the area saturday into sunday. As to be expected with a feature like this, models are highly variable from run to run but seems like an opportunity for some severe weather for someone. Biggest concern overall for me right now is the extent of destabilization that occurs given that cloud cover/junky convection look assured given lack of an EML. GFS overall has been the most "impressive" member of guidance which has had a stronger surface low and therefore a more organized low level response and backing of winds. Not a super impressive setup by any means even on the GFS, but when it's 2020, you grasp at straws.

really cant help but think we see storms struggle to maintain supercell structure tomorrow, but I dont know of any analogous environments. just that effective shear and cloud layer shear are far below the threshold you'd expect. Don't think we go unpunished for that so to speak. That being said, 400 0-1km SRH and ~150 0-3km CAPE are probably good for something. Would probably be staring at a moderate risk if the profile above 500 wasn't worse than garbage.

Tomorrow’s setup in IL/IN is completely foreign to me and I honestly have no idea what to think of it. Especially the hodographs. 0-6km shear is nothing short of substantial and likely results in storm motions exceeding 40kts, but wind aloft is significantly backed and in much less magnitude. The result is a hodograph I’ve literally never seen before where it doubles back on itself. What the result of this is, perhaps rain on inflow? Similarly, never seen 0-6km shear contrast with abysmally low EBWD that is typically far too low to support supercells. To me, storm speed seems to suggest that this environment appears far more sheared than it actually is in a storm relative sense. If storms can initiate on a confluence zone in S IL or elsewhere, my guess is that we get fast moving clusters of storms and transient supercell structures with perhaps a few tornadoes owing to large SRH values present(note the sounding posted is on the conservative end of guidance) I’d feel better if EBWD and cloud layer shear weren’t in the gutter. Thermos should be sufficient but not stellar and shear aloft is better with northward extent tomorrow. Definitely interested to see what results from this.

This is easily going to be one of the worst storm chasing seasons of all time.

The storms a few nights ago dumped on me. Measured 1.98”.

This month is just about locked in for the worst May ever. Far cry from how things looked even 10 days ago. Tomorrow/Saturday could be decent but its not gonna save the month. It really is fascinating considering that the second half of May looked good as late as May 13th.

Can we just take a moment to appreciate the beauty of this?

In other news, tomorrow looks conditionally fun for some low topped supercell action and perhaps a few tornadoes assuming atmosphere sufficiently destabilizes. Environment is very similar to today's setup in the Arklatex and is reminiscent of classic low topped supercell days.

Finally getting around to it, but I also chased the HP supercell in Iowa last Thursday. I never did find my localized area of backed winds, but was bored and needed something to occupy my time so I went out anyways. Storm went up farther west than I thought it would, initiating all the way back by I35, when I was expecting initiation near Oskaloosa or Ottumwa. Arrived on the storm near Melcher Dallas and found it to be OD and sucking strong but cold inflow. This is just how this storm was, and never at any point while I was on it did I think it had any significant tornado potential. Chased it to near Washington, where I let it run over me and went back to catch some rainbow/sunset stuff. Core was far more intense than I was expecting it to be however, and I encountered what I would crudely estimate to be winds in excess of 75mph and some pea size hail. Fun local chase overall.

The NAMs show the type of environment I’m looking for with regards to tornadoes. Both have an area of localized backing in W IL with good thermos.

I would ideally like to see more surface backing tomorrow(to SSW or even due S) than is currently modeled if I were forecasting for tornadoes. Storm motion is also boundary parallel, but that doesn't seem like a variable that is likely to change. Lapse rates through 500mb per 18z runs are actually quite steep (all exceeding 7.0*C/km) and would support a damaging wind and potentially even a hail threat should any supercells evolve. I'll be out if it looks like any enhanced corridors of low level shear are likely to evolve. Looking pretty sloppy regardless.

Looking at medium to long-range ensembles, the signal for a potentially active pattern is really quite strong(especially given the range) and it's hard not to like what is being shown. First off, subtle system coming into the west next week will probably yield some chase worthy days with a potential lull for a few days over the weekend.By weeks 2/3 things really get interesting, the modeled jet extension starts to come into play here and this is where that super consistent -- both run to run and model to model -- signal is located. Northern hemispheric pattern is also following a rather textbook evolution that tends to lead towards active periods for plains severe wx potential and supports this evolution. The current ridge over the Yukon/Alaska slowly retrogrades with time and ultimately ends up somewhere over Eastern Siberia. Furthermore, a ridge looks to build to a limited degree over Hawaii, with multiple strong waves crossing the pacific on a track for the western US courtesy of an active jet. Looking like the long-range could evolve into a fairly active stretch and given the range there's really quite the signal for it. It also makes sense with AAM/GWO transition but the mechanisms of how AAM and tropical forcing mettle with patterns is not my cup of tea (though to be fair none of this hemispheric stuff really is). One last thing is that the AAM/GWO transition is not as amplified as last year which might mean that the resulting pattern is not as amplified (someone correct if wrong), and if that is the case, combined with an Actually Present EML™, could set up a really nice chasing period. I'm obviously very optimistic.However, one thing that does put me on hold here is the tendency for low latitude troughing to show up on some ensemble runs. The gulf is cooking this year so whether or not this actually has any significant effect with such a strong gulf and being in the second half of May remains to be seen, but it is there off and on and is worth noting.But for now, let's just treat ourselves with this. 18z GEFS pacific pattern gif just because:

Sleeper setup that could be alright if moisture/thermos are there. Nothing high end and there's a ton of uncertainty regarding convective evolution, but these tight surface lows kind of have a hot hand in 2020. I'll be keeping a half eye on it for potentially a local chase Tuesday.