January Dry Spell & Lots of East Wind

January 10, 2019

10pm Thursday…

Today was nice wasn’t it?  Bright sunshine filtered through high clouds and temperatures for most of the metro area well into the 50s.  I mentioned Sunday that we’re headed into a slower weather pattern again; that sure is the case this evening.

Highlights

  • I expect little or no rain until at least next Wednesday; you get at least 5 dry days
  • Increasing easterly wind through the Gorge and out into the metro area should keep fog just about non-existent
  • That wind will be persistent and strong east of I-5 in the usual east wind areas; West Hills and west slope of those hills too.
  • Expect lots of sunny days, sometimes with high clouds, and cool/clear nights
  • High temperatures drop a bit early next week as a “cold pool” develops east of the Cascades below about 4,000′

We are in a “split-flow” jet stream through the middle of next week.  Tomorrow morning’s GFS forecast of 500mb heights shows an upper-level ridge building over the Pacific Northwest and a system heading toward California

gfs_namer_012_500_vort_ht

Then by Sunday a strong pocket of high pressure is overhead while California gets a soaking

gfs_namer_072_500_vort_ht

This general setup continues through Wednesday or Thursday.  We get little/no rain next 6 days but almost the entire California coastline gets at least 2″, maybe much more in spots

ecmwf 7 day rain total wgauge usa

Meanwhile up here in the Pacific Northwest I expect a pool of cold air to develop in the lower elevations east of the Cascades.  This happens when we get strong high pressure overhead between November and late February.  Cold dense air = high pressure and it’s trapped east of the Cascades.

Of course that cool air will surge westward through the Columbia River Gorge; 24 hours a day through at least next Wednesday.   We just went through a period of chilly east wind and cold rain the past two days; today the pressure gradient dropped to a very weak 2 millibars from The Dalles to Portland.  But it’s already back up to 5 millibars, headed to at least 8-10 millibars through the weekend.   The result?  Expect the usual 55-70 mph gusts in the western Gorge and 75-90 mph gusts at Vista House.

Enjoy the sunny (but not so warm) weekend; quite a bonus in January.

What do we see farther ahead?  Well, there’s absolutely no sign of low elevation snow/ice in the next 10 days.  We may get something in the Gorge Wednesday/Thursday as moisture returns next week, but not west of the Cascades.

We will see some brief westerly flow and wetter weather the 2nd half of next week and the following weekend.  Models are then trying to develop strong high pressure near the West Coast beyond that time.  The next 3 weeks of the ECMWF monthly run last night show the cool/wet setup late next week then drier weather the following week or two as high pressure develops along the West Coast.  We’ll see, seems like models have been trying to develop these big highs too often this winter, backing off as we get closer.

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Here’s the 32 day rain anomaly.  Of course anything beyond two weeks is a real guess, although it’s interesting this is a typical mid-late winter El Nino setup.  Wet California and Dry Northwest.

eps_qpf_768h_west_129

And here’s the ECMWF ensemble snow forecast for Portland…obviously no sign of any snow.   One lonely ensemble member out of 51 thinks there could be a dusting in the hills one day late next week…  #SAD

kpdx_2019011012_eps24_snow_360

The other night Wayne Garcia pointed out how weird it is that we haven’t even had snow CLOSE.  No reporters standing up at Sylvan brushing slush off the barkdust so far and no sign of that in the next two weeks.   I live at 1,000′ in the far eastern metro area.  This is the first time in at least 14 years that I’ve had no snowfall (at all) through early January.  Even in the bad years I have seen at least a half-inch or more by this point.  Strange stuff this year.

Chief Meteorologist Mark Nelsen