Snow Chance For Friday Increasing

December 18, 2013

10:30pm Wednesday…

Models have speeded up the timing of the return of moisture Friday morning.  What does that mean?

MarkSnow_PortlandOutlookPercentages

MarkSnow_PortlandOutlookPercentages2

Our RPM model has actually backed off a bit on possible snowfall at that time, showing just about everything north and east of the metro area.  However the UW-WRFGFS model has painted a larger area of snowfall over us sometime after 2am Friday:

wrf_snow

Notice the 2″ forecast for Scappoose, St. Helens, and most of central/north Clark County…more moisture available in those areas.  And if the faster timing continues in the next 2 model runs, just about all of it happens before the sun rises.  As a result it could be snowy morning commute across the far northern part of the metro area.

All models show a rapid warmup several thousand feet up after 7am now.  Snow can’t keep falling after that time for just about all areas.

We’ll be watching closely to see what tomorrow morning’s runs show.

Chief Meteorologist Mark Nelsen