Quincy

I'm not sure where the warm 700mb idea came from, but several people have been mentioning it on Twitter and elsewhere. 700mb temperatures were around +10C when I looked this afternoon and there wasn't much of a capping inversion in place. However, an area of CINH was analyzed over northwestern Kansas, likely a result of clouds limiting surface heating and somewhat lower dew points than forecast. Note that convective temperatures in northwestern Kansas were in the lower 80s, but temperatures struggled to get above the mid/upper 70s. I've spent the past hour and a half writing a post mortem about this:

Late May has a way of squeaking out severe, even if regional (or even local patterns) don’t look particularly favorable. Yesterday had some sneaky severe reports too.

Current storm NW of Goodland is still displaced a bit too far west of an area with much better low-level moisture to the east. I’m watching it and it’s still somewhat elevated and attempting to organize. If it can hang on for another 60-90 minutes, then the tornado threat will begin to substantially increase.

The environment near the western KS/NE border is going to rapidly become very favorable for tornadoes around and after 7 p.m. Let’s see what happens.

Fairly high confidence in a corridor with intense supercell potential from northeastern Colorado into southwestern Nebraska on the nose of a lee cyclone. The parameter space should become very favorable toward and just after 00z for a couple of tornadoes. Forecast soundings show enlarging hodographs and more than ample instability. I wouldn’t be surprised if SPC adds a small ENH risk area, but then again, they’re not predicting for storm chasers. The environment in northwestern Kansas also looks conditionally favorable for an intense supercell, but capping and less focused forcing lead to some uncertainty there.

Put up a thread on Twitter to go into more detail. Just pasting to save typing. If I was going to pick a conditional target area, it would be western North Texas into southwestern Oklahoma. Maybe near Wichita Falls. A storm could thread the needle, but I expect mostly an HP mess.

Not sure what to make of today. The atmosphere is recovering across Oklahoma, but not quite enough. The convection surge has pushed all the way to the Arklatex, outrunning sufficient deep layer shear for supercells. The outflow boundary in western North Texas looks the most intriguing. Large CAPE and marginal shear. The intersection with a dryline and/or cold front are interesting, but CAMs have been performing poorly and may not be resolving CI in the right areas My gut says we see messy blobs of convection by mid to late afternoon. We’ll see.

I opted for the tail end Charlie near Liberal, KS. When I got there, it was struggling and I almost went home, but I’m glad I didn’t. This supercell reintensified and an even better organized storm popped up to its immediate west. I watched this slow moving, distinctly structured supercell for about an hour before it got dark. Got lucky with the lightning self portrait, even though it’s a little cut off. Camera was set to 1/15 and the first shot wasn’t in focus. The second happened to catch some lightning off to the side.

Kansas mesonet obs show dews mainly in the mid to upper 50s around southwestern Kansas, about 2-4F lower than these obs:

Wind profiles are not ideal today, but I’d expect semi-discrete storm modes for at least the first couple of hours before an MCS begins to develop. Tomorrow’s setup heavily depends on the nature of the MCS overnight/early tomorrow and where the outflow boundary ends up. I could foresee targets ranging from western North Texas to southern Oklahoma or the eastern Oklahoma/Ozarks vicinity. Some CAMs suggest the OFB may linger near or retreat back to I-44 in Oklahoma, but I am skeptical about that. Here’s another vantage point of the scene I captured last night:

The last month of May in the U.S. with less than 100 tornadoes was 1970 with 88. http://www.tornadohistoryproject.com/tornado/1970/5/map

Started in Wyoming today. Chased a couple of initial supercells forming near the Laramie Mountains. Not much worth sharing. Next, dropped into the Nebraska panhandle into a more moist low-level environment, but the linear convection kept unzipping southward. Finally watched a tail end transient supercell put on a lightning show in northeastern Colorado. One of my goals this year is to step up my lightning photography game, which could use some work.

The setup tomorrow is a bit similar with a bulge-type feature leading to a locally enhanced area of low-level shear. Wonder if it’s a repeat, but will keep that talk to the other thread. I bailed on the Montana chase idea today. They did have a few transient supercells, but didn’t want to get too far out of position for tomorrow or play around with the complications that come with out of state travelers there. Even though I barely had any contact with anything there, outside of my shoes on the ground.

I’ve had an opportunity to look more closely at progs for tomorrow. Upper level winds are unidirectional and display some VBV characteristics, especially across the northern High Plains. It does not help that deep shear vectors will be nearly parallel to the initiating boundary in most cases. Low-level CAPE looks minimal at best. With that said, wind profiles show enlarged low-level hodographs with 850mb winds SSE/SE. My guess is there could be a few initial supercells before storm mergers and surging outflow turn the storms into a linear mess. CAMs are varied with where CI will occur, but really a tall swath up and down the High Plains could see activity.

The synoptic pattern favors episodes of severe thunderstorms from the High Plains, across the central/northern Plains through mid to late week and potentially continuing through this weekend. The trough axis over the Rockies early this week should initially favor the High Plains Wednesday/Thursday and gradually shift east across the central states in the 2-3 days following. I’ll defer further discussion to y’all from here on out, as I’m trying to not get too caught up in the medium range. Wednesday features an enhanced (ENH) over the far eastern Wyoming and adjacent areas...

Quick glance for the deadly Louisiana tornado... About 35 knots of bulk shear with 500mb winds out of the NW, backing to SW at the surface. Marginal MLCAPE ~500 J/kg, however there was sizable 0-3km MLCAPE around 100 J/kg. A localized area of 200-300 m2/s2 0-1km SRH was also noted. LCH didn’t launch a RAOB, but the 00z 5/18 SHV sounding gives a rough idea of the mid to upper profile. There was more backing of low level winds where the tornado occurred, resulting in larger 0-1km hodographs. https://www.spc.noaa.gov/exper/soundings/20051800_OBS/

I’ll take a look into this... Had a few transient supercells in Montana today, but the instability axis was too narrow and meager to support anything more. Tomorrow’s setup is in the same general area, except moisture return should be better.

Dragged myself up to Montana for a couple of days... Never chased this far NW before. Today might see a high based supercell. Tomorrow looks more favorable. Either way, deep layer shear is impressive and it doesn’t take much moisture at these elevations... Wednesday looks like a mess up and down the high plains with unidirectional mid/upper level winds. There should be some backing of low-level flow, but I’m not overly excited at this point.

Caught a shelf cloud in Iowa before it got dark:

I followed that storm into Iowa. It looked really interesting for a while, but low level rotation was not very focused. Did see a lot of very low hanging appendages though. It died upon crossing into Iowa.

The Arklatex setup has some tropical characteristics to it. Definitely not something you’d usually see in May.

It does. I haven’t cracked its code yet... Today looks interesting, but I do see a few potential caveats. First, low-level instability looks good, but CAPE profiles aloft should be quite skinny. Second, low level winds are backed, but forecast soundings show only modest enlargement of 0-1km hodographs. Moisture looks sufficient and breaks in the clouds are allowing for some destabilization. Forcing is a little bit nebulous prior to 00z, but storms could initiate in three regimes: 1. In the narrow warm sector as capping is minimal. 2. Near an effective warm front. 3. On the SW flank of ongoing convection. It looks like the strongest forcing does not arrive until after sunset. I still think a few storms can initiate, but if upper level support was just a bit faster, I think we’d have a higher ceiling. On the flip side, modest forcing might save this from rapidly blowing up into a sloppy mess. I’m interested to see how it turns out.

Heading toward northeastern Colorado. Not the most impressive setup, but wind profiles along with modest instability might support a supercell or two. Not playing with that junk in Oklahoma. Deep layer wind profiles are hideous for mid-May.

I caught the beginning stages of that storm:

A few areas to consider today... The most obvious seems to be southeastern Kansas. With strong/extreme instability and modest shear, I’m not sure if we’ll see a clustered mess or a slow-moving supercell just before 00z. It could go either way. The dryline/front intersection out west looks interesting, but large T/Td spreads and marginal shear could lead to junk as well. Keeping an eye on Colorado and Nebraska as well for good measure.