It seems that a brief period of light synoptic snow is fairly likely for most of northeastern Ohio Thursday afternoon. It probably struggles to stick in most areas, but some hilly areas may see a slushy coating.
As for lake effect, the air coming down at the end of the week is much colder than the airmass we saw last weekend when accumulating snow was mostly confined to the highest terrain in SW NY, however, the fetch is short which adds different complications.
Water temps are still fairly toasty in areas that we care about for a NW flow event, though the waters over western Lake Erie are into their yearly free-fall…
The airmass Thursday night into Friday features 500mb temps of -32 to -35C (even colder near BUF), a difference of 45C or so over central and eastern Lake Erie. 700mb temps will be -22 to -24C, a 35-38C difference, while even 850mb temps will be -11 to -12C, a 24-26C difference. These values are all extreme. The issue is fetch and how long any lake effect lasts.
The Cleveland sounding at its peak is perfectly fine, with extreme instability and EL heights over 15k feet, little shear, and moisture depth to almost 10k feet. Unfortunately, this look only lasts a few hours with moisture depth and inversion heights falling quickly towards morning.
The Erie soundings are nuts, and last longer, well into Friday morning. There is a bit more shear, but that seems to be partially due to the model trying to simulate an intense lake effect band off of Lake Huron that is messing with the wind fields.
With our short fetch events, some sort of synoptic lift and/or upstream lake connections seem to be mandatory for good snow…
The Lake Huron connection should go into extreme SW NY or NW PA (the NAM does swing it west after this image). As usual with a NW flow, there will be some sort of Lake Superior/Michigan connection into the Cleveland area that can bring a narrow band or two of enhanced snow, especially in the hills. This connection likely dies down early Friday as the ridge builds in, though the Lake Huron one may last through a good portion of the day Friday.
The models do swing a weak shortwave through late evening into the overnight Thursday night. This would help for a few hours, though after this passes the ridging starts building in from the west and the environment becomes less conducive in NE Ohio (again though, downwind of Lake Huron will be conducive into a good chunk of Friday).
The above image is the NAM BUFKIT “overview” for Erie…the red contours are omega, greater than -15 is considered to be strong. The fill is RH (height is on the right), the snow growth zone is the pink/yellow outlined area that is sitting from 4-10k feet Thursday night through Friday, the low-level wind direction is plotted by the dotted lines (direction in degrees on the left), and time is on the bottom (in Z time). A busy image. But, what it shows is a classic “cross hair” signature (strong lift in the snow growth zone) for about 12 hours late Thursday night into Friday, indicative of heavy snow potential, with the winds only shifting slowly…moisture depth doesn’t really decrease until Friday evening. It is really hard not to get warning criteria snowfall with this type of signature.
My overall guess for NE Ohio is 1-3″ for most areas (perhaps little to none right along the lake) from Lorain and Medina Counties points east, even as far south as Akron/Canton and Youngstown. Short duration, short fetch events usually underwhelm, though with a NW flow many could see that light accumulation of snow. If the upstream connection parks in the hills south or east of Cleveland for several hours late Thursday night into Friday morning someone could see locally several inches, but I think that’s the exception and most see an inch or two.
For NW PA this seems like a very favorable setup, though whether or not the band slowly moves around or sits somewhere may determine how high the totals get. I think a widespread 3-6″ in interior NW PA (and extreme SW NY) is a decent bet, but locally up to or over a foot if the band off of Lake Huron is organized enough. The lakeshore will see less, but under the Lake Huron band can accumulate decently.
Let’s see how this trends over the next couple days…and probably more chances coming up with even colder air next week. I’m in NE Ohio for a few days around Thanksgiving, let’s not freeze the lake before then!