Not much change in 00z models tonight with most of them just skirting the Portland metro area with snow later Thursday night and Friday morning. If there was any movement, the precipitation is slightly closer to us. Here’s the WRF-GFS model showing accumulations of snow as close as the western suburbs and down around Woodburn and then south.
Still looks great for at least 1″, maybe more, in the areas mentioned in the previous blog posting.
Our 00z RPM is even more white than its earlier run, producing a swath of decent snow all down I-5 from Olympia to Medford! I’m ignoring it…for now.
Models are now pushing even colder air than expected down out of Canada later Friday through Sunday. I see the NAM and GFS both have 850mb temps down to the -12 to -15 range. That would be about 10 degrees fahrenheit at 4,000! We haven’t been below the -12 to -13 range since before 2007…I don’t know when. The lowest in December 2009 was -12.3 at Salem, and -12.5 in November 2010. February 2011 and December 2008 only bottomed out around -10. The 2008 number surprised me. Of course what models predict and what actually shows up on the sounding can be different.
Regardless, we have a true “arctic air” weekend coming up here in the Pacific Northwest. High temps only in the upper 20s to 30 in the metro area. Low temps in areas with bare ground and calm wind should be in the 10-15 degree range. If we get snow cover down the valley, it’s going to be the coldest we’ve seen down there in many years…into the single digits!
Chief Meteorologist Mark Nelsen