Mon, Dec 9, 2013 winter storm forecast for Sat, Dec 14

Computer models predicting extended forecasts.

1:00 p.m., Dec 9, 2013 comment by JustaSooner at ToledoTalk.com:

Last couple of GFS runs hinting at a possible significant snow for you guys by the weekend. Forecast will likely change around a bit, but will throw this out there.

QPF - total liquid equivalent of precipitation

Timeline
By Midnight Saturday AM - Light snow dev, 0.05-0.1" QPF, < 1" Snow
Midnight Sat to 6AM Sat - Moderate snow, 0.25 to 0.35" QPF, 3-5" Snow
6AM to Noon Sat - Light/Mod Snow, 0.15 to 0.25" QPF, 2-3" snow
Noon to 6PM Sat - Light Snow, 0.10 to 0.15" QPF, 1-2" snow
6AM Sat to Midnight Sun - Light snow, 0.05 to 0.15" QPF, 1-2" snow
Midnight to 6AM Sun - System snow ending, < 0.05" QPF, < 1"
Remaining of the day - some snow showers from lake effect off of Lake Michigan possible.

I went with a basic 10:1 ratio for the snow amounts here, though forecast soundings indicate that the ratio could be closer to 15:1 at times, especially towards the end. This is all worst case scenario stuff as things evolve a lot being this far out. Air profile doesn't support sleet or freezing rain, so at least icing should be minimal. Snow range on this model run is about 7 to 14" across the Toledo metro area.

! posted by JustaSooner on Dec 09, 2013 at 01:01:55 pm # +

Mon morning, Dec 9 area forecast discussion by the Cleveland NWS:

long term /friday through sunday/ [dec 13-15] ...
more wintry weather expected during the long term period. will
start the period out dry friday but precip chances will increase
friday night into saturday. the new 00z models have differing
solutions but both give the area another round of snow. the ecmwf
solution which has been more consistent and is preferred today has
low pressure passing to the south with an inverted trough swinging
across the local area. this setup is favorable for accumulating snow
and if the 00z run is correct some areas may need headlines. the
gfs has a much more northern low but also gives several inches of
snow to the area. expect confidence to increase as the week
progresses and the models sort themselves out.
! posted by jr on Dec 09, 2013 at 01:45:26 pm # +

Mon evening, Dec 9 TT comment by JustaSooner

Toledo area specific timeline on the latest models.

12Z Euro Model
Friday through 10PM: Snow starting from the SW, no accum.
10PM to 1AM Sat: Light snow, 1-2"
1AM to 4AM: Light snow, 1-2"
4AM to 10AM: Light/Mdt snow, 1" north to 3" south
10AM to 4PM: Light snow, ~1"

Worst case: 4-8" snow

18Z GFS
Through 1AM Sat: Light snow starting, < 1"
1AM to 7AM: Mdt/Hvy snow, 3-5"
7AM to 1PM: Mdt snow, 2-3"
1PM to 7PM: Light/Mdt snow, 1-2"
7PM to 1AM Sun: Mdt snow, 2-3"
1AM to 7AM: Light snow, 1-2"
After 7AM: Scattered light snow/squalls from Lake Michigan

Worst case: 9-16"

So the main take away...

Models are being consistent now about bring in a snow storm up the Ohio River valley at the end of the week. It is likely that there will be an area of heavy storm. The exact path will vary and intensities will jump around a bit the next few days. The GFS is pretty intense right now on amounts and a lot of that is due to projected strong wrap around. It wouldn't be unrealistic based on the forecast surface winds to assume there will be some lake enhancement to the snow for the Toledo area - as rare as that usually is.

Late Saturday there is a chance some warmer air will get pulled up and this could induce a bit more sleet into the precip, which of course brings snow totals down.

Again, nothing locked in. I've seen GFS switch 48 hours out and have a completely different solution. However, right now ECMWF and GFS are in a pretty good agreement overall - so that deserves attention.

! posted by JustaSooner on Dec 09, 2013 at 06:08:06 pm # +

My Tue, morning TT comment regarding the morning's area forecast discussion issued by the Cle NWS:

Tue, Dec 10, 2013 - 6:39 a.m. NWS area forecast discussion

long term /saturday through monday/...
an interesting forecast shaping up.
the 00z models are in much better agreement than they were yesterday. the gfs has come around to the ecmwf solution of low pressure passing to the south. later shifts will have to monitor this but for now will go with all snow. there is a good possibility some headlines may be needed.
! posted by jr on Dec 10, 2013 at 09:09:14 am # +

Noon time, Tue, Dec 10 TT comment by JustaSooner

Quick run down of the latest models precip amounts...keep in mind these are going to keep fluctuating, so just expect that it is going to snow. :)

All amounts are snow using 10:1 ratio.

00Z Euro/ECMWF
Through 10AM Sat - Trace to 1" (east to west)
10AM Sat to 1AM Sun - Light Snow, by 1AM an add'l 2-3"

Totals down to 3-4".

12Z GFS
Through 1AM Sat - Trace to a half inch of snow.
1AM to 7AM - 1" to 2"
7AM to 1PM - 0.5 to 1"
1PM to 7PM - 1 to 2"
7PM to 1AM Sun - 1 to 2"
After 1AM - System snow ending, < 1"

Totals: 3 to 8 inches.

! posted by JustaSooner on Dec 10, 2013 at 12:09:51 pm # +