Lots of Wet Ahead! November Gray & Rain Here to Stay

November 7, 2017

6:30pm Tuesday

This fall has been a bright one with lots of sunny days but still plenty of rain in between those days.  But now it appears we’re headed into a long period of gray and rain.  Let’s hit the highlights first:

  1. After today I don’t see a single totally dry day in the next week and beyond.  In fact it’s possible we get some sort of measurable rain almost every day the next two weeks!
  2. Expect a lot of gray, but that is normal from November through February…get used to it, book tickets for the tropics, or drive about 16 hours south on I-5.
  3. Through Saturday the rain won’t be very heavy, but weather systems will likely be stronger NEXT week.
  4. There is no sign of valley snow/ice in the next 10+ days; this will be a mild and wet weather pattern, in fact a bit warmer than what we saw today

You want to see gray?  Take a look at the ECMWF cloud cover forecast from all of the ensembles.  Blue=cloudy, white=clear

Note that almost the entire two-week period the ensemble average is more than 80%.  Then see the total rainfall forecast for the next 10 days.  Lots of rain, yet no specific setup for flooding or a pineapple express.

In the short-term we’ve got a classic Gorge ice/snow storm setup for Wednesday and Thursday…except the atmosphere is just a bit too warm to get either one all the way down to freeway level.  If you live up above 500′ (more likely closer to 1,000′), expect your first snow to ice event starting Wednesday afternoon and continuing through at least Thursday midday.

Peak gusts tonight through Wednesday evening at the west end of the Gorge will likely reach 70 mph in the usual cold-season windy spots.  That’ll be accompanied by sideways rain and 35-40 degree temps…not real pleasant I think…

There is one big bit of good news though…this wet pattern for the lowlands will turn into a heavy snow in the Cascades.  Snow levels through Sunday generally remain above the passes, with a good foot or more accumulating at the ski resorts above 5,000′.  Then we get a HUGE dumping Monday through Friday next week.  ECMWF shows a solid 3-4 feet snow at/above pass elevations:

Even if we get half of that, there’s a good chance we’ll have some decent skiing starting up the weekend before Thanksgiving.  If so, that’ll be fantastic to get the ski season started in mid-November!

Chief Meteorologist Mark Nelsen

 


2 Dry Days, Then Classic Wet November Weather

November 5, 2017

7pm Sunday…

This was sure an interesting weekend weatherwise as an extremely early season “arctic front” (leading edge of cold and dry air) dropped south, west of the Cascades, to around the Twin Cities and then fell apart Friday evening as it passed farther south through Kelso.  That’s about what we expected.  That gave a dusting (or more) of snow to parts of Puget Sound.  Then an area of low pressure at the surface moved across southwest Washington last night and this morning, bringing a gusty southerly wind to all areas west of the Cascades in the KPTV viewing area.  On the north side of that low, snow fell all the way down to sea level in spots today.   So Puget Sound ended up with 2 little “snow events”.  One could argue that it’s now SEATTLE 2, PORTLAND Zero for this “winter” so far.

The ECMWF model was by far the best forecasting this event; you may remember the GFS and even the GEM models kept showing today’s low coming right down into NW Oregon to our south.  Well, we now know that COULD have brought snow all the way into the metro area (or for sure the Gorge) IF those models would have been correct.

Moving along…

A surge of cool air (and high pressure) will pour south into Eastern Washington tonight and give us a 2-3 day period of strong easterly wind through the Gorge and into the east side of the metro area.  That begins Monday afternoon and continues all the way through Wednesday.  This will be the first “cold” east wind of the season.  Highs will only be in the 40s, compared to low 60s with the wind last week.  Quite a change!  Keep in mind you can not go to Vista House to experience the wind through the foreseeable future.  Fire never made it to that location so I’m not sure what the reason is for keeping the road blocked 1/2 mile before that point.  Rumor says that MAY be the situation the entire winter.  We’ll see.  But the good news is the dry easterly wind will give us two dry days…Monday and Tuesday.  Enjoy, because we’re going into a rainy pattern starting Wednesday and continuing through the next 10+ days.  Take a look at the ECMWF ensemble 24hr precipitation forecast.  Each horizontal line across the top is one of the 51 ensemble members.  The lower blue part is the ensemble average, showing several peaks of precipitation forecast.

The only real obvious breaks in there are the next two days.  But it gets gloomier; check out the cloud cover forecast for the same period.

Wow…that’s a lot of gray!  The ensemble average for cloud cover is around 80% through the next two weeks.  Hmm, seems like November to me!  Total rain in the next 10 days or so doesn’t appear to be excessive since systems will be relatively weak

There IS some good news if you are a skier.  Snow levels will rise after tomorrow, and linger in the 4,000 to 5,000′ range through most of the next week.  The result is additional snow base-building at the top of Skibowl and a good part of Timberline and Mt. Hood Meadows ski areas.

I think there should be a solid 2 feet or more on the ground in those locations, not just fresh snow but a building base.  This is a good sign that we might have a good start to the ski season like last year.  #FingersCrossed.  Down at Government Camp it’ll be a mix many days during the next week so you folks will likely lose some of your 10-12″ on the ground right now.

So there’s no sign of a real stormy pattern (wind or flooding), and no sign of low elevation snow or freezing rain in the metro area.  Now depending on how cold the airmass is in the eastern Gorge Wednesday, it’s possible we get either snow or freezing rain out there, but we’ll see about that.  Might just be up in the higher valleys away from the towns.  More on that in the next two days.

Enjoy the dry weather!

Chief Meteorologist Mark Nelsen

 

 


Snow To Sea Level Up North, But A Chilly & Wet Weekend For Us

November 2, 2017

7pm Thursday

November is here but the weather pattern the next 5 days looks more like December.  That means cold rain showers in the valleys and lots of mountain snow, plus some snow (above freeway level) is likely in the Columbia River Gorge too before the weekend is out.

Today we actually have an “arctic front” sitting across the northern part of Washington State draped east and west from an area of low pressure over the Strait of Juan de Fuca.  I’ve colored it in red on this sea level pressure map.  You can see the cold air north of that line.

It’s a boundary line between chilly/moist Pacific air to the south and dry/cold modified arctic air to the north.  North of the line sticking snow is falling down to sea level (or very close).  A gusty northeast wind is blowing across NW Washington and snow fell today (on November 2nd!) at the border crossings you’ve likely used to get to Vancouver BC.  The arctic air has pushed south due to a northerly flow in the upper atmosphere from NW Canada all the way down to Washington

Overnight the low pressure will weaken and drift south.  But the cold burst of northeast wind won’t make it any closer to us then around Seattle west of the Cascades.  That leaves us with scattered showers and a snow level down to around 2,000′ or so the next two nights in our area.  Friday will feature a mix of showers, sunbreaks, and cooler temperatures.

A 2nd disturbance drags more of that arctic air over the Pacific Ocean and spins up a low pressure center Saturday evening.  That low moves inland across SW Washington Saturday night and Sunday.

This means another burst of snow in the Cascades and valley showers later Saturday through Sunday.  Luckily the low is passing by to the north which will minimize any cold air getting pulled westward through the Gorge.  One of the inferior models (GFS) was showing just this setup in the past few days, but it has now come around to the “warmer” models.  That said, in such a chilly airmass it’s always possible we’ll see snow at the eastern end of the Gorge.  If you live in the upper Hood River Valley or anywhere else near/above 1,000′ at the east end of the Gorge there’s a pretty good chance you’ll wake up several inches of snow Sunday morning.  If the low comes any farther south than forecast, snow could fall very close to river level too…if it does.  Here in the metro area our wind should be southerly, pushing snow levels up to around 3,000′.

To summarize:  The next few days will be cool and showery in the lowlands, with highs only in the 40s Saturday and Sunday.  Lots of snow will fall in the mountains, but snow won’t stick at any point below 2,000′. 

How much snow in the Cascades?  The ECMWF seems reasonable bringing a total of around 2 feet above 5,000′

Once the Sunday system exits, we’ll be left in a cool and mainly dry beginning of the week (Monday & Tuesday).  Models diverge quite a bit for the 2nd half of next week.

The more reliable ECMWF shows mild atmospheric river event the 2nd half of the week and into the following weekend.  This would of course bring more rain than snow to ski areas.

But other models keep us in a cooler pattern with several more surges of cool air coming in from the northwest the next two weeks.  Regardless, you can enjoy this early taste of a winter chill!

Chief Meteorologist Mark Nelsen