Kaner88

Severe PTSD after the current system, I figure a starting point of 1" makes it difficult to disappoint. (though at least 2" seems believable even on drier guidance)

Hoosier singlehandedly selling me the straws I'm grasping

Has also sped up the Arctic front slightly across Chicagoland... not looking forward to it

All we need is the 0z GFS and Euro yanking this storm west 150 miles and this thread is done for

This is giving me PTSD flashbacks to a Christmastime storm a few years back when I stayed up late into the night comparing every pixel on the SPC mesoanalysis MSLP charts to what the HRRR/RAP suite was showing as a big low moved through Indiana, to sniff out any signs the low was actually gonna be west of where models had it (giving ORD more snow). Needless to say, it did not happen.

time

Thru hour 12

Third straight run of outright halving QPF in Chicago from last night's 0z Euro... from 1.2" to 0.15" in just 36 hours. Not a great performance by model guidance across the board with this storm.

Question becomes, what happens if the Euro goes with the GFS? And to a smaller (but more likely) degree, what do we do if the Euro kinda ticks west to a middle zone between non-GFS 0z guidance and the GFS? Places Chicago in a tricky spot. Edit: Adding to the trickiness is the GFS ENS almost doubling downtown Chicago QPF from the 18z run to ~0.5" through Saturday AM now.

Gonna say 4" here roughly near ORD with some wicked winds & cold, can't go thru the emotional rollercoaster again like the GFS wants me to jump on

0z GFS QPF.

Can't believe I'm spending my Tuesday evening comparing 500mb vorticity ribbons across Wyoming and Colorado from the 0z NAM to previous runs

18z Euro actually a tick east after Hour 60 as the low crosses northwestern Ohio; leads to a small shaving of northern IL QPF.

Not sure what you're getting at, as RC explained in the first thread these snows are unlikely to be 10:1 but will also struggle to reach the kind of ratios that spit out higher numbers via the Kuchera method. Somewhere in the ballpark of 15:1 ratios appears appropriate for this storm.

LOT updated snow forecast range.

18z GFS QPF through late Friday PM early Saturday AM... suppose you could have Chicago somewhere in a 6-8" range if we stick with a 15:1 average ratio or so

Straw grasping in full effect, seems like the 18z GFS is showing the slightest slowing as the energy drops down through the Rockies, a modest reversal of previous trends (see attached gif).

Snippet of a detailed LOT AFD, with the smallest of bones tossed to us snow weenies in bold. Personally very impressed with the intensive messaging re: winds and cold, saying not to focus exclusively on snow when it comes to dangerous impacts. * Our storm system trended more progressive (faster movement and farther east track of strong surface low) vs. earlier forecasts, which will limit the snow amounts vs. earlier thinking, though confidence is still lower end on exact snow totals. Barring a notable change back to earlier model solutions, the snow amounts will be on the moderate side (roughly 3-7" at this vantage point), with possible exception of Porter County Indiana. This area may be close enough to be in the envelope of the heavier deformation snows on western fringe of the cyclone as well as see some modest lake enhancement contribution. Given the large swings over the past few days in the model guidance and the complexities of the setup, some shifts back to a slower and farther west surface low track (and more snow) are a lower but not zero probability scenario at this point. * For the above reason, the message continues to be a de-emphasizing of snow amounts and an overarching emphasis on the combination of falling snow, strong west-northwest winds (peaking Friday) causing blowing and drifting snow and potential blizzard conditions, and temperatures and wind chills crashing to dangerous levels that will result in dangerous to life threatening conditions for anyone who gets stranded outdoors. * We cannot stress this point enough. Do not focus on the snow amounts (which will be difficult to measure as is). The conditions later Thursday through Friday night will be more akin to what is common in the northern Plains vs. our portion of the Midwest. Any non-local travel is encouraged to be rescheduled. Forecast temperatures stay below zero through the day Friday, with wind chills on Friday bottom out at 25 to 35 below zero, which will be the the coldest conditions for most of the area since late January 2019. There is expected to be light very small Arctic-type snow or at least flurries falling late Thursday night through Friday, exacerbating blowing and drifting snow issues, particularly in open areas, with exposed north to south roadways most susceptible. Higher snow rates potentially persisting through Friday in parts of northwest Indiana (especially northeast Porter County) may increase the risk of true blizzard conditions there.

Impressive Heavy Freezing Spray Watch for Lake Michigan, usually don't see freezing spray stuff outside of Alaska in my experience.

It would only be fitting that this storm ends up plowing northwest again, led by the 18z ICON or something

I suppose the biggest question now is, for those more knowledgeable, is this looking like a believable final track or do more shifts appear in the cards? Between snow coming in above expectations in the Pacific NW & recent model trends favoring east shifts, feels like no one knows what's happening (or, more accurately, I have no clue what's happening).

I've got family wanting to know if they should make the drive from Nashville to Chicagoland Friday; my initial reaction was no but if we're set to get like 3" in the city, doesn't strike me as the kind of crippling blizzard set-up that was being advertised (both in terms of amounts, obviously, but also shifting the focus of winds east towards MI). This is a mess

ECMWF has now halved QPF for Chicago for two straight runs... 24 hours to go from 1.2" to 0.3" QPF

LOT forecasted snowfall through 6 AM Friday; issued before the mess that these 12z models started bringing, but after the 0z suite.

Judging by the neighbor that is currently running their snowblower in the driveway, I'm assuming local news hasn't backed off on the blizzard stuff (at least in terms of snow totals; winds are still there, of course) quite yet