Monday Evening Update

November 10, 2014

9:30pm…

Get ready for strong wind tomorrow!  The National Weather Service issued a High Wind Warning this afternoon for the metro area and Cascade foothills, forecasting gusts as high as 60 mph from the east as cold & dry air out of Canada surges south and over the Cascades.

Most locations will see gusts in the 35-50 mph range, but the favored spots (Battle Ground/Hockinson) could see winds a bit stronger in gusts.  We’ll see how that works out.  Either way a beautiful day with the air turning very dry and blowing all the leaves off the trees.  Sunshine from sunrise to sunset.

Pretty much the same thing for Wednesday as my thinking from last night’s post hasn’t changed much.  Models are waffling on the cold air a bit.  For example the WRF-GFS says The Dalles will be 35 tomorrow and PDX’s high will be 40.  It’s running too cold.  I think it’ll be more like 38 and 45.  Or PDX could be even warmer.

I still don’t see snow west of the Cascades Thursday unless we get a spot up against the east slopes of the Coast Range or the Scappoose/St. Helens area.  Our RPM and the soundings from the WRF-GFS say no snow for the metro area since there will be a warm layer up around 3,000′.

Freezing rain west of the Cascades?  Looks unlikely, but there may be isolated spots of icing since it appears the precipitation will be holding off until close to sunrise Thursday.  This will be determined by how cold the airmass ends up over us by Wednesday.  We’re really not sure how well models are handling that airmass yet.  Here are the graphics I used this evening:

MarkSnow_TextPanel MarkSnow_TextPanel2

As for the Gorge…wow!  Evening models have a LOT of moisture for heavy snow/freezing rain.  We don’t lose the easterly flow, so the cold air is going to last awhile.  This COULD be a historic November snow/ice storm out there.  Take a look at the WRF-GFS snow forecast below…a solid foot or more in the central/eastern Gorge during the 24 hours from Thursday to Friday morning.  The thick ice (freezing rain) at the west end of the Gorge (Corbett and hills above Washougal) would be devastating with .50″ to 1.50″ rain equivalent.

or_snow72.84.0000

That forecast is ever so slowly backing off on snow here in the western lowlands.

So that’s it for now…batten down the hatches for wind tomorrow.

Chief Meteorologist Mark Nelsen


Past Events Can Help Current Forecasts

November 10, 2014

1pm Tuesday Monday…

Just a quick note as I’m making my forecast.  Take a look at the blog post from the freezing rain event on March 1st.  The one where the WRF-GFS was forecasting snow in the cool east wind part of the metro area?  It ended up being all rain in the metro area except freezing rain east of I-205 (not on roads).  Freezing rain at my place at the west end of the Gorge and ice pellets from Bridal Veil east.  This was the snow forecast map:

wrf_snowendsundayam

Look familiar to those of you checking out all the maps today?

Models were too cold that time around and it’s real interesting to read past thoughts as the event approached.  Take a look here:  https://fox12weather.wordpress.com/2014/02/28/a-chilly-windy-march-weekend/