purduewx80

What’s your flake quality like?

Hanging your hopes on one operational model run will usually end in disappointment.

Doesn’t quite go out that far, but GHD 1 is showing up as the number 3 CIPS analog for Wed eve.

Alaska was most definitely not ice-free. The mountains were glaciated, while the interior was ice-free because it was a desert. Moisture sources were farther removed due to much lower sea levels.

Not sure I've ever seen it, but it's similar to when we have a connection to another Great Lake (Superior-to-Michigan, Huron-to-Erie/Ontario, etc). In this case, the heat, moisture and ice nuclei from smokestacks is pre-conditioning the atmosphere, so the band ends up being stronger.

There should be a 3/4hr band where the 850-700 frontogenesis sets up - easy over on ratios there. Northern parts of the modeled QPF have the forcing above the DGZ, so those areas would be pixie dust. Pretty wild to see another winter event with summer-like 700-500mb lapse rates.

Kinda hard to see on the composite, but the TMKE terminal Doppler reveals that industry in WI is contributing to the heavier lake effect bands affecting areas near and NW of GRR this morning.

Having a hard time buying the forcing lasting into eastern MI. Most guidance has an energy transfer to the coast which is why the snowfall amounts should gradually taper from what IA/NE see.

Just poked through that 06Z HRRR run, wow. Pretty much ideal for at least 20:1 - light winds, lift in the DGZ (which is 9k-10k feet thick!) and 700-500mb lapse rates 6.5-7.5. 06Z NAM frontogenesis at both 700 & 850mb would also imply a swath of heavy snow across IA into far S WI, N half of IL/IN and S 1/3rd MI.

Nice convective look to the vis shot. Just saw a flash NE of BMI. Should be some bursts of +SN the next couple hours in Chicago. Gonna be nasty if/when everything freezes up later in the eve.

same here in the city. how...shocking.

That's bright banding, where precip is mixing and/or snow is melting. No lightning in that area though the precip is convective.

About as good as it gets w/ lapse rates at SGF this morning, though dry air is factoring in. 8.9C/km max mid-level lapse rates, and 8.3 from 700-500mb, w/ 147 J/kg of MUCAPE. Max lapse rates 2-6km are similar in a pretty large area of the warm sector.

Nice altocu field at sunset this evening, indicative of the already steep lapse rates below 500mb.

Hahaha beat me to it.

Feeling pretty good about seeing some TSSN in the region tomorrow. Will want to see lapse rates verify on the 12Z TOP and SGF soundings. At the very least some swaths of 1-2”/hr rates are probable.

Giving me 07-08 vibes when I lived in Madison.

Won’t hear me complaining about 35 and sun prior to a weekslong bullshit air mass. Go outside.

Correct! Looks like it's 1058.5 mb

Energy looks strung out and less phased, so it’s overall not as warm ahead of the front aloft nor does the low deepen as much. Still will have some areas that cash in on a few hours of mod/hvy snow tomorrow.

Lake effect belts should do extraordinarily well over the next week or two. Probably talking several feet of snow given the air mass and vortex just north of the Lakes.

Pretty big changes upstairs (see below), but it didn't really translate to much difference at the surface. The splotchiness of snow accumulations in these parts is indicative of dynamic cooling. Probably going to have to rely on that south of ~88/290 as others have mentioned. Don't think we should disregard that scenario given the ingredients showing up on a lot of guidance: steep lapse rates, 500-250mb left exit region dynamics, highly focused WAA, but air temps will almost certainly be above freezing for at least a few hours S/SE of wherever the surface low ends up tracking. Whatever snow ended up falling in those areas may not accumulate on roads (unless it's heavy) but could add to the snow depth a bit.

It is totally different with the upper energy on every run. Most of the short waves involved still aren’t in its domain so it will probably jump around for at least another 24 hours.