Rain and Mountain Snow On The Way

January 28, 2014

Tuesday, 11pm…

A nice wet evening out there with a good quarter to third of an inch rainfall in the metro area so far.  That was nice after a total forecast BUST this morning; couldn’t believe it when I looked out the window at 9am and it was dry!  Grrr…

Now we have a very warm flow of air coming in from the southwest and that will continue through tomorrow afternoon.  With surface low pressure passing by to the north, we should see a southerly breeze developing later tonight for most of the valleys west of the Cascades.  The result will be temps in the 50s!  Enjoy, because then we’ll turn chilly for the next 7-10 days.  Probably not COLD, but just cool with snow levels between 1,500′ and 3,000′ until further notice.  The bad news is that we just have one dumping of snow the next 48 hours and then it’ll be mainly dry for the following week.

MarkSnow_MtHoodFcst_2013

I’d avoid skiing tomorrow and go for Thursday and Friday as a result.

Here in the lowlands our weather will remain quite dull over the next week as high pressure pushes a bit farther offshore and we get into a split flow jet stream pattern.  Or a ridge just to our west.  Either way, not a whole lot of anything happening.

Over the past few days, some runs of some models have been hinting at an arctic blast the middle/latter part of next week.  That would be from ridging building farther north into Alaska; putting us in the cold northerly flow behind it.  I haven’t mentioned it either on the air (because it’s past the 7 Day forecast) or here because I haven’t seen much consistency.  The 00z GFS and 12z ECMWF ensemble charts generally keep the real cold stuff away:

tseries_850t_000-360_Portland tseries_850t_000-384_Portland

Of course there are plenty of cold members and quite a bit of uncertainty.  The 00z GFS operational model is a warm outlier, but not outside the range of possibilities.  The new 00z ECMWF is very similar (no chart yet), showing a very splitty and weak flow through an upper-level ridge offshore next week.  Take a look at Day 10…that’s some weak sauce!  In fact this latest run has no rain in most of Oregon for 7 days again beginning this Friday afternoon.

500vty_f240_bg_NA

Chief Meteorologist Mark Nelsen