Well, isn’t this getting interesting? At 8pm we can see snow coming down at 1,800′ on our KPTV tower and snowflakes mixed in with the rain on our Fox Tower Camera (450′). Temperatures are falling steadily due not to radiational cooling, but cold air pouring inland. But first a scolding about "wishcasting". In forecasting class up at the UW we were taught to be very careful about this…you really want something to happen (snow) so your forecast basically veers towards what you want to see. There was a ton of this on the comments the last 24 hours. Many of you were convinced the low was headed into Oregon even though EVERY SINGLE model showed it moving inland somewhere either in Western Washington (GFS, ECMWF, MM5) or Vancouver Island (NAM). In the end the GFS-MM5 from the UW once again NAILED it with a passage around Hoquiam then inland to Seattle. I for one am amazed the model can do so well. If 2 weeks ago before the windstorm I would have suggested the low was heading into Newport instead of Hoquiam, I would have been laughed off the blog. My forecast would have been for light north wind instead of gusty east wind. So why was the "snow low" different? It wasn’t and the main reason many were expecting it to go south was because they (I too) would really like to see snow. So my point is to watch out in the future, but there’s nothing wrong with speculating on possibilities either.
Forecast tonight/tomorrow is pretty simple…very cold onshore flow continues until late tomorrow evening. Snow levels are down to around 1000′ right now and will hover between sea level and 1000′ through tomorrow. That means anyone COULD see snow, but it’s far more likely as you go up in elevation. There doesn’t appear to be a ton of moisture, but 2-4" at/above 1000′ seems safe. A heavy shower band could dump 1" even to sea level but that’ll be tough to do during the daytime. Some sort of dying "arctic front" seems to come through here tomorrow evening, then it’s on to dry offshore flow for Wednesday. Gorge winds kick in Tuesday night. That gives us a chilly 35 or so (with sunshine) Wednesday.
00z GFS is insistent on busting a weak system inland Wednesday night or Thursday morning. Obviously that’s either a snow or freezing rain producer. It won’t be a prolonged event because the low is going by to the north as it passes through Canada, unlike our ice storms where a low swings by to the west and then moves offshore again…Mark