andyhb

Satellite image of the extensive blowdown in Iowa from yesterday’s derecho. You can see the tracks of the individual MCVs and bowing segments that enhanced the winds near/north of Des Moines, and then the US 30/I-80 corridors through Marshalltown towards Cedar Rapids and the Quad Cities.

Been watching this elsewhere and that is absolutely an historic derecho for Iowa. Extreme high end gusts (and a lot of them), the duration of damaging winds, it tracking through the most densely populated corridor in the state. Not sure I've ever seen such a duration of 100+ kt returns with any single derecho as I saw with that (from both the DMX and DVN radars). I'd have to imagine some of the reports from outside the bigger cities like Cedar Rapids, Iowa City, and Des Moines are going to be frightening. Particularly in the region along US 30 and I-80 between Des Moines and Cedar Rapids (Tama, Marshalltown) and also NW of Des Moines near Madrid. Can't imagine what Iowa State and the UI campuses look like right now, but I'd imagine it's something along the lines of a war zone.

New TDS west of Springfield.

This might help.

The last several weak Ninas (1996, 2002, 2006, 2009, 2012, 2017, 2018) haven't exactly been promising for severe season either with quiet Mays and Junes for the most part. Would be a real downer after this year went completely down the drain post-April.

Still needs to spread west more if we're going to get a stronger event.

The AA precip over almost the entire Gulf suggests a quiet Gulf?

That shortwave that ejects into the Plains behind it is at a pretty low latitude and it quite strong for June. Would think there could be a considerable severe threat with it assuming the two are separated by a decent degree. CIPS analogs are loaded with big events, but obviously there's a wrench in there with Cristobal.

Curious as to the severe potential with this once the more tropical thermodynamic profiles are somewhat muted into Wednesday. Anomalous wind fields at all levels and plenty of low level moisture would indicate the potential for a pretty significant squall at the very least. A lot of things depend on the speed of Cristobal through the area.

Fixed.

Amphan in the Bay of Bengal up to Category 4 status, rapid intensification occurring.

3 km NAM joins the party near the Capital District into S VT. Can't say you pull area-averaged soundings like this too often up there.

Pretty solid agreement from the 00z convective allowing models (HRRR/ARW/NSSL) for a few supercells in upstate NY and then tracking along the MA-VT/NH borders later. I'm not a huge fan of the relative lack of steeper mid level lapse rates, but at least low level lapse rates are half decent leading to some rather large 0-3 km CAPE. Good wind profiles as well, wouldn't sleep on this setup up there.

Wednesday next week looks like a good opportunity for slow-moving supercells, sign me up.

Not that the upcoming pattern for the next week or so will be great for severe prospects, but this is indeed getting a bit repetitive. Two days after you posted the bolded, there was a localized tornado outbreak along I-35 in S OK that was probably the best April chase day in a portion of the Plains in awhile (along with more tornadoes on 4/24 in SE OK/NE TX).

Estill SC tornado upgraded to EF4.

Really like today's setup south of I-40 in OK. Likely a couple of outflow boundaries to interact with for storms coming off the dryline, plus winds (as of now) are remaining more backed than in model guidance. Residual capping may also encourage rather photogenic storm structure in addition to the tornado threat.

What? Mid-late May is climatological peak season for these areas.

SREF popping a 90 this early (FH 72) is a pretty good indicator of a problem on Thursday.

10+ violent tornadoes and the rest of the numbers usually follow suit. Any outbreak like that automatically earns the title "historic" in my book. Actually any outbreak with more than a half dozen violent tornadoes does so. There are other factors such as location (see: 5/31/1985) and time of year (e.g. 1/21-22/99, 2/5/08) that also factor in.

Pressing X to doubt moisture mixing out that severely so close to the Gulf with unimpeded return flow. Not like the temps are in the upper 90s or 100s either.

Probably worth noting that while the progged warm sector on the models is not especially extensive in terms of northward extent, it is very extensive in the longitudinal (W-E) direction. This matters when you have a setup with westerly winds aloft.

Wouldn't be shocked if we end up with two EF4s out of that lead supercell.

Absolutely nuts.

Good stuff, retweeted.