This is going to be brief...I will provide a more detailed view tonight.
I have just taken a look at the latest (18 UTC) NCEP (NWS) model runs, the U.S. and ECMWF ensembles, and the runs from major modeling centers (UKMET, CMC, etc). The trend is much more threatening for Wednesday and it appears that we will have a major, highly disruptive snow event.
The big question for days...the question on which the forecast depended on...was where the trough/low pressure would go. Head north of us, we get perhaps 4-8 inches of snow, followed by a few hours of rain and then the whole thing starts melting. The snow would start around 3-4 AM on Wednesday AM. This is the best case (if you don't like a crippling snow event)
But some models...some very good models...were taking the low farther south, which would extend the period of snow or prevent a turn over to rain altogether. The Canadian GEM and UKMET office were going this way. Then then NWS NAM for the 12 UTC (4 AM) run. In the 18 UTC run both the NAM and the NWS GFS (normally the best NWS model around her) is taking a more southern route. And the 15 UTC NWS SREF ensembleis doing the same thing (at least the ensemble mean). Ok, this is getting a bit techy..sorry.
The bottom line is that there is a serious threat on Wednesday of 8-15 inches of snow over the region, with a minimal turn over to rain. The biggest snowstorm in years. Anyway, before anyone goes out and buys a snowblower, lets see what tonight's runs show. If they continue this trend then Slushmageddon might be replaced by Snowmageddon. In almost any conceivable case, Wednesday morning is going to be very problematic for travel...I suspect there will be a lot of school cancellations and the like.
The main roads around Seattle are in very good shape now, but the Wednesday event could dwarf the weekend snow.
More excitement: My lost dog Leah was just spotted near 64th Ave W & 222nd St SW in Mountlake Terrace.