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3/1 - 10AM EST - Update
Latest indications are going forecast looks good but will tweak the area involved and amounts up slightly. The heaviest area of snowfall should extend across Washtenaw and Wayne counties into portions of Livingston, Oakland and Macomb. Generally 4-7" are likely in these areas rather than 3-6" due to change-over likely a bit earlier in some areas. Isolated locations better than 7" possible in areas where snow accumulates on faster due to lower air/ground temperature. Be advised the snow will be wet and heavy as temperatures fall slowly into the lower 30s by evening. Also; a period of rain mixed with snow and sleet is possible before the change-over.
2/28 - 230PM EST
After beautiful, early spring-like weather these past several days; winter will roar back for the first day of March with strong, gusty east-northeast winds shifting to north, rain - moderate to heavy at times - and to top off the day; snow some of it coming in moderate to heavy bursts. Since rivers were and still are on the higher side, how much rain/snow that ultimately falls may aggravate earlier problems. For the latest river data; follow the NWS River statements and forecasts if issued. Another issue that may crop up will be the potential of ice pushing west and jamming along with higher water levels along some of the shore waterways due to the strong east winds backing to northeast, then north by late in the day. Fortunately, the system will be fairly quickly moving so the conditions won't be long lasting.
My interest in the possibility of the stormy system was first sparked back last Sunday while looking at the models and remarking to my a few of my colleagues. There was a possibility, in my view of the beginning process of phasing of jets over the southern Great Lakes as a low moved across the Northern Ohio Valley/Southern Great Lakes. I will say; the models have had a devil of a time trying to project how much cold air would be available at the surface and even more importantly, aloft. This is not surprising as I have witnessed other late winter scenarios where this was a problem. This combined with the vertical lift and available moisture was setting the stage for a potential big mess Thursday into Thursday night. With the jet folding and phasing of the polar stream and subtropical, this is, at the very least one of the more complex systems this winter.
Since this forecast has been somewhat difficult for some of the main models to come to a general consensus; especially snowfall - where and how much - let's look at the most recent projections of the GFS and NAM together and my preferred forecast & maps . Note the GFS & NAM models have stepped up in a consensus.
Upper jet /500 MB/ @ 1PM Thu 3/1
PREFERRED PREFERRED
Surface Maps @ 1PM Thu 3/1
PREFERRED
Snowfall Totals @ 1AM 3/2
PREFERRED SNOW AMOUNTS
PREFERRED PLACEMENT
To the NAM's credit, the GFS has been the most erratic in both placement and amounts the past few days. The GFS has projected the snow to fall mainly over the central and even northern part of Lower Michigan. This action actually follows it's pattern this winter with major storms and in my opinion, has been the more unreliable performer of storms followed between it and the NAM. The European has also been more erratic this winter. Looking at the latest 12Z data, The NAM appears aggressive with snow amounts and doesn't take a realistic account the warmer grounds and low level temperature. However; following the models all week, it seems to me it had a better handle on earlier upper jets and snow placement but not amounts.
I'll update later today on my Facebook Weather Historian page with mainly shorter term models
Making weather fun while we all learn,Bill Deedler -SEMI_WeatherHistorian
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