nsrobins

I have no reputation for identifying storm initiation but am hoping to acquire one through this escapade (sic. Red Dwarf). Storm mode sig supercells initiating on OFB in wake of earlier MCS in a line Joliet, IL to Lafayette, IN from 20.30Z this afternoon. Potential for long-track tornado it the cell roots to the boundary.

Well what do I know?! SPC update has shifted the risk area SOUTH and Chicago Metro now only Slight zone. These guys know what they're doing for sure but they must be totally dismissing the HRRR and NAM4K ppn output.

According to SPC archive there have been no HIGH risk days so far 2015. The last HIGH risk was 3rd June 2014. There have also been no PDS issued in 2015 as far as I know. Am happy to be corrected. Anyway, hasn't happened yet but don't be surprised in an upgrade is considered for this evening. The next SPC output is due 13.00Z. Given another HRRR run showing cells on the very N boundary of the current MDT risk, an adjustment north in area is likely to include the whole Chicago metro region.

HRRR has shifted the greatest sig supercell risk north towards the Chicago metro area from 21Z, plonking a discrete cell right over Chicago itself. This is being closely monitored I would think, and should parameters consolidate in the next few runs I wouldn't be surprised to see a conditional HIGH risk being introduced given the population density at threat.

Some detail now on spatial distribution of risk for Monday with SPC pinning a 10% hatched over most of IL. The instability can't be doubted (some output has in excess of 5K worth max cape by 20Z), but there is no definitive tor level shear that I can see (edit: always check before posting. There is infact a decent 500mb flow over backed surface central IL) but I think what's driving the risk is finer mesoscale level (OFBs) so if I was chasing I'd be watching the MCS and the associated outflow. Still the Potential exists tonight for a few strong tornados

Two dates carved in stone for the next few years - A two-week Midwest chase 2016 and then the big one - a total eclipse US tour 2017. Live the dream!

An unseasonably moist and unstable set-up looks likely to develop from IA east and south through Monday - Wednesday next week. All severe threats including significant tornados are likely.

Interesting situation in next few hours as a line of tornadic supercells bears down on the St Louis Metro area. Parameters could maintain their discrete nature until they threaten St Louis, or else they could well line out with attendant SLW threat. Either way a severe weather risk continues through 02Z Mon.

A warm welcome home to the Netweather chasers after a fantastic roller coaster season. Floods, hail, tornados, lightning, thousands of miles and even the Northern lights have entertained us for the last seven weeks or so. A big thank you from me for sharing your stories, and even allowing me to catch you up on a couple of occasions. The bonus shelf cloud and nocturnal tornado we shared together near Colby, KS was one of the highlights of my chase. Roll on 2016 😎

Fortunately for residents around the Lakes a less severe evening than many models forecast. Another one for the 'wasn't it, didn't it' scrapbook

Still balanced this evening in the SE WI and N IL metro area for potential strong tornados. The ingredients are there but confidence in the timings coming together is low hence SPC are holding an upgrade in risk for a few more hours. Regardless the environment behind the MCS complex that will move W to E over the region by early afternoon is modelled to become explosively unstable with 5000+ CAPE available under a screaming 80kn W 500mb jet and a SSE surface inflow. EHI values of 8+. Should monitor obs later as the tornado risk will be linked to the backing surface flow IMO which in turn will be dictated by the surface low and trailing CF position. We might be in a position that tornados (waterspouts) develop over the lake itself.

The 12Z NAM today if anything increases the chances of violent long-track tornados in S WI and N IL Mon afternoon. Some of the highest EHI and SRH values (bulk shear 70kn) this season anywhere in an impressively unstable environment must surely be a concern for the metro areas of Milwaukee and Chicago.

I might look at this in more detail later once Fathers Day duties are over. 00Z NAM places some upper wind profiles over the region, which would put metro areas including Chicago at risk IMO from a strong tornado Mon pm

Some sort of severe end regional event is likely in the Great Lakes region of WI and IL on Monday afternoon, with an SPC Enhanced at 3 days (quite rare). The usual model spread exists but the general pattern with a very strong upper WNW flow overriding high CAPE would promote rotating supercells in the deep layers with attendant tornado probabilities. Worth keeping an eye on if you're into late season virtual chasing.

The MDT was raised for enhanced winds, in association with the bowing MCS that is currently racing across north IA and MN. 90mph+ wind gusts being reported. Not all categorical risks are for tornados.

Powder keg instability in target area. Meso shows nearly 3500 max CAPE over Gillette, WY and effective shear up to 60kn. I would expect cells to explode over the far NE WY in next half hour and grow upscale later into a mean beast of a bowing MCS.

I don't think you're far off the right area today with a shift North into W central SD or maybe over into far NE WY. The highlight of the parameters has to be directional shear, with it maxed out at 180deg between the surface and 700mb according to the hodo near Newell, SD at 22Z. Yes weakfish flow at the surface but pretty decent at 500mb which probably accounts for the concern in a fast-moving bow/derecho later with attendant damaging winds. Tornado chances fairly decent early on IMO in target area (Spearfish/Newell SD) and HRRR pops up a cell at 21Z near to Devil's Tower, WY

I acknowledge your point, but if you can see through the inevitable technical issues the chasing and terrain up in the central and high plains is some of the best there is IMO. The workaround for the virtual chaser is to use a combination of the NW info flow and some of the other live feeds available (TVN, ChaserTV for instance), and on active days embed the live news channels who regularly break in to schedules to stream storm coverage. I think the term 'apathy' is more perspective than subjective.

That's what happens when you spend too much time with Cling-ons

I'm going to start a discussion for a slight risk 5% tor for the above area Tues 16th June. 09Z HRRR confirms earlier RAP in developing one or two decent looking discrete supercells in far NW NE and far E WY at 21Z. I like the area between Harrison NE and Lusk WY for shear as the LLJ cranks things up later. Could be a residual boundary to look out for. Edit: GPS puts you in Lamar now. You could get to far NW NE by initiation but it might be breakfast on the go. An alternative would be to chase upslope in SE WY, but IMO tor risk is lower here. This begins a three day play in roughly the same region.

It's actually not surprising. Once you get West of the 214 it really is totally open and empty for miles on end.

I love those timelapses, and a great choice of music: 'We are Here' AKA 'Two Steps From Hell'. Quite appropriate actually.

Welcome to the party to Tour 4 and good luck in your travels.

Paul my interpretation of current output suggests an interest exists in E CO Thurs afternoon should the timing of impulses trigger initiation here. The LLJ looks favourable for rotating storm in an upslope regime.

There is certainly a correlation between ego and the number of antenna (in theory of course). I can understand maybe two long antenna (one mifi signal booster and one shortwave radio), but some of the vehicles I saw had over half a dozen of various lengths and floppiness. I also wonder at the validity of hazard light gantries. One team (Minuteman disaster response) had blue emergency service lights which may or may not be official. If their primary purpose is to follow a tornado damage path and assist if necessary then I could understand it. Although the vast majority of chasers would stop and assist, I fear not all do and of course very few tornados actually impact populated areas anyway.