Best Christmas Vacation Skiing in 3 Years!

December 28, 2015

9:30pm Monday…

What a run of snow in the Cascades the past 2 weeks or so!  The result has been the best snowpack for late December we’ve seen since December 2012.  Note the snow depth at 5,400′ (Mt Hood SNOTEL site) the past few years on yesterday’s date:

MarkSnowpackDecember_SkiAreas

And that means the snowpack is ABOVE normal across the entire state of Oregon!  The best news is across the southern half of the state: almost double the typical late December snowpack right where we need it.  This will ease the drought quite a bit, especially if we get normal or better snow down there the rest of the winter.

MarkSnowpack_Oregon_PlusFacts

A dramatic change has occurred though, models are showing a very dry pattern for the next 10-14 days…well into the 2nd week of January at least.  A weak system just misses us tomorrow, we’ll get a few showers but that will be it.  Otherwise upper-level ridging will develop later this week over and north of our area.  That will divide storms and/or send them to the north.

MarkJetStream

The result will be warmer than normal temps in the mountains over and west of the Cascade crest.  In the lower elevations and east of the Cascade crest…well, it’s mid-winter and that means big-time inversions developing later this week.

We do have a situation in which we’ll see stronger and colder than “typical” east wind through the west end of the Gorge and metro area too.  That’s because the vast majority of the Pacific Northwest is covered in snow.  Take a look at the snow cover map today, which obviously isn’t perfectly accurate since we know there is no snow on the ground in the Tualatin Valley!

nsm_depth_2015122805_Northwest

It’s probably fair to assume the areas that show less than 2″ on the ground don’t actually have any on the ground.  But the point is that most areas east of the Cascades are cold and snow-covered.  With strong high pressure developing Wednesday and beyond, we’re going to see 10-14 millibar easterly gradients through the Gorge.  Probably Thursday-Saturday will be 100+ mph days at Crown Point, with temperatures only around 30!  Too cold for me , heck, I was freezing up there when it was in the low 40s.  Lots of ice on Gorge waterfalls by this weekend as well.  Gentlemen…start your cameras!

Here in the metro area the combo of the wind and chilly air will give us the coldest weather so far this season.  In fact if we don’t have an arctic blast in the next 6 weeks, this may quite possibly be the coldest weather of the winter.  Calm areas should drop into the 15-20 degree range Thursday and beyond.  This should be mainly a “gap” wind event with strong wind confined to the usual east wind spots.

I am very confident we do have lots of sunshine ahead Wednesday through at least this coming Sunday.  It’ll just be cold!

Chief Meteorologist Mark Nelsen


ECMWF Monthly Run

December 28, 2015

Looks like ridging or split flow is here for the next 2 weeks.  Definitely an “El Nino” look.  We’ll see about the 2nd half of January.  These are ECMWF weekly 500mb height average maps from last night’s 45 day run.  Warmer colors are heights higher than normal (ridging), cooler colors heights lower than normal (troughing).  This is an average of all 51 ensemble members: