As data becomes bettered sampled, I believe the track of the low may bit a further north then the Ohio River Valley, closer to the NAM guidance at 12z and now 00z. This track would take the low from the St Louis area...slightly east northeast to between Indianapolis and Evansville...across Dayton to south of Columbus. This system will have an ample supply of moisture coming in from both the southwest and later; the gulf. That's one of its big pluses for snow amounts, a broad area of moisture. The big negative will be the cold, Arctic high in the northern lakes funneling dry air into the Saginaw Valley and Thumb leading to a distinct cut off of the heavier snow. I've upped the snow totals based on the strong consensus of the model precipitation; albeit still allowing for a bit of a cut back of the NAM snowfall totals. See general snow amounts forecast below:
I feel the NAM's storm track and GFS snowfall are better inline to what I'm seeing most likely for the event: There will be a rather sharp line of demarcation from north to south with this system. Look for 1" - 4" north/south in the Saginaw Valley and Thumb Region; 4" - 8" from the Flint area east across to Port Huron and then south into the Ann Arbor area to Metro Detroit. Further south across the Southeast corner of Lower Michigan 7" - 10" of snow is possible.
As the system continues to be better sampled, look for updates on this evolving storm.
Original -1/30/15 -
Our meteorological guidance is converging on a likelihood of a snowy Super Bowl Sunday across Southeast Lower Michigan; particularity in the south. All the latest model information tracks a low pressure center across the Ohio Valley on Sunday. Depending on the exact path of the storm will determine snowfall amounts across the region.
At this time; given the guidance and meteorological background; I think the NAM is too wet and predicts too much snowfall over Southeast Lower Michigan (5" - 12"+ - highest south). Whereas the GFS's track and snowfall are better inline to what I'm seeing most likely for the event (1" - 3" north & 3" - 7" south). Not surprising (as compared to the GFS), the European and Canadian Models are painting a similar picture for extreme Southeast Lower Michigan as far as snowfall but with just an inch or two over the far north (Saginaw Valley/Thumb region). Of course; as better data is sampled tonight and tomorrow these amounts could change but that's the way it looks to me at this time.
Our NAM Model:
Has the track of the storm center the furthest north (and thus the most moisture
and snowfall) with the center moving across central Indiana and Ohio.
Our GFS Model:
Has the track of the storm center a bit further south across the Ohio River Valley (and somewhat less snowfall) with the center moving on a line pretty much from St Louis thru Louisville to Cincinnati.
The European /ECMWF/ Model: Note in two time panels 12z Sun and 12z Mon with the 60Hr N/A; moves is further south across mainly southern Missouri and central Kentucky to southern W Virginia.
The Canadian /GEM/ Model:
It is pretty much in an agreement with the Euro and moving it across the Ohio River Valley.
I'll update with later guidance on Saturday, or if need be... late tonight.
Bill Deedler -SEMI_WeatherHistorian