purduewx80

For sure. Literally the best model tool in the game IMO.

So what you’re saying is, neither the 10:1 or Kuchera maps are 100% accurate? Definitely agree on the locally higher ratios wherever the better meso forcing sets up. Probably lose some of that to riming and fracturing I’d think.

Yes, exactly. There is a large amount of collaboration that takes place and consistency from office to office is pretty much essential. This is true in both the private and public sector. Ultimately all of that will usually end up producing a superior forecast rather than letting one person or idea drive the bus.

Primary differences though are that we have no terrain to enhance convergence, and y’all also have salty ocean air which can produce efficient snowflakes at warmer temps. I kinda feel like the warmer temps and stronger winds near the lake here Monday will negate any modest lake enhancement. Tuesday is a different story if the colder/slower solutions verify.

Always fun to come in here and see people who aren't meteorologists question the decisions made by the professionals. Easy to be critical when you're hiding behind a screen from a dark corner in the basement. LOT explained their reasoning for not issuing a watch, I'm sure we'll see DVN's here shortly. The products look to be consistent with other NWS guidance, particularly from the WPC. 48-hour probabilities for at least 8" of snow: Surface low track w/ ensemble positions plotted (indicating the amount of spread in both timing and track/location):

The overnight AFD didn't say that. It's definitely still offshore. The system tomorrow is already well inland now. AFD for reference, it's a doozy:

What's also interesting about the synoptic light snows into Tuesday, is that we have steady cold air advection in the lowest 3KM or so with a lengthening fetch over the Lake. This 12Z RGEM sounding for Tuesday afternoon would result in a much deeper DGZ, high-ratio snow and the potential for significant additional accumulations. Most other guidance isn't quite as cold though.

Haha nice. Climo says no.

In case you missed it, the PDF in Ricky’s link mentions an airline official at ORD reported 1” of accum in 10 minutes. 6”/hr rates are extraordinarily rare around here and are usually observed in areas with forced orographic lift or in Nor’easters where you have moisture transport off the Gulf Stream and strong frontogenesis. In this case it was more the forced ascent caused by that compact vort in an atmosphere w/ steep low-level lapse rates centered in the DGZ.

TSSN in SW WI. Looks like a narrow swath of heavy snow is accompanying the intensifying vort max.

speaking of persistence, another morning of anthropogenic snow in the midwest:

I wouldn’t go that far. “Convection” does not mean lightning and thunder are always involved. The convective profile would need to favor cloud tops at or colder than -30C for sufficient charge separation, and there isn’t much evidence of that in current guidance. At least locally, cell motions do not look all that rapid. Steering flow is only 5-15KT, so I think some of these will end up producing surprise amounts tomorrow, especially near any enhanced surface convergence. Nowcasting will have to involve looking for local “heating”, upper level vort max support and any surface troughing, which is similar to what we look for when forecasting thunderstorms in the summer.

Counterpoint, by a virologist, to the science fiction opinion article written by the clever writer a couple weeks back.

This is an area average sounding at 3PM Friday for the Chicago metro from the RGEM. Surface-based instability that includes the DGZ would be a good setup for mod/hvy snow showers.

p.s. it's still there on the 00Z run

It is pretty bizarre. Working in aviation, we pay a lot of attention to cloud heights, depths and in-cloud temperatures. It would be hard to do a historical analysis, but we have seen this persistent pattern since late November where cloud depths are too shallow and warm for significant lake effect. At the same time, there has been an increased incidence of aircraft icing on their way in/out of ORD and MDW. These conditions are also what have led to the prevalence of aircraft- and industrial-effect snow.

In case you missed it.

Would love to know why none of you It'S nO bIg DeAl types are ignoring the other long-term health consequences, many of which we probably don't even know about yet. There are an increasing number of studies looking into the decline of brain health, among other lasting issues. For all we know, the president's widely reported detachment from reality could be a direct consequence of his infection last year.

That's been happening a lot this week! With all the fog and low clouds around, we have more than enough moisture. Local industry has largely been feeding the surprise flurries/snow showers (likely a combo of heat/steam and particulates that act as ice nuclei). There have even been isolated locations around that have picked up 1-2" of accumulation where they've been more persistent.

Nice! Yeah, It's too shallow for DTX or APX radars to pick up. These echoes are from the closer-to-the-lake and more sensitive terminal doppler, TMKE. It doesn't looks as impressive on the NWS radar.

Some legit lake-effect in southeast WI this morning. Remnants should eventually make it to Chicago, but I imagine it won't be quite as intense. Kenosha: KENW 081401Z 35006KT 1/4SM SN FG OVC012 00/M02 A3030 RMK AO2 P0000 T00001022 Racine: KRAC 081405Z AUTO 03012G21KT 1/2SM SN FG OVC005 01/M01 A3031 RMK AO2 P0001 T00061006

JFC that is science fiction. He is a literal fiction author, not an expert on anything related to any of this.

It really was incredible out in Aurora. South-facing surfaces collected the most due to the light S/SW breeze today.

They’re showing up on the terminal Doppler radars. Pretty clear they’re smokestack/industrial-effect given the point plumes. You can see this on the early AM vis sat too where plumes are creating locally deeper clouds.

Heck of a -NAO developing on most guidance now for early January. Will get the East Coast weenies in a tizzy. That trough in the Gulf of Alaska would flood the US w/ mild Pacific air, though.