No Freezing Rain This Morning

December 15, 2017

8:30am Friday

I’m not working today, but figured I should check in and let you know that we’re in the clear now.  NO FREEZING RAIN THIS FRIDAY AM, or at least nothing that will freeze on roads. There have been a few reports of a windshield or deck getting a brief icing, but that’s it.  We knew today was going to be a close call: a clear night with temps below freezing followed by rain arriving at sunrise.

web_metrotemps (1)

The good news is that clouds arrived a few hours ago and temperatures have risen to or above freezing. ALL METRO ROAD SENSORS SHOW PAVEMENT TEMPS WELL ABOVE FREEZING. East wind has also ended so no new “supply” of chilly air is on the way. Enjoy the return to cool & showery weather without the wind!

Speaking of wind…it’s gone!  As forecast the easterly gradient is down to almost nothing this morning after 11 days of strong east wind.  Relax and enjoy the quiet if you live in/near the western Gorge.  But don’t worry, our old friend (East Wind) will likely be back for Christmas Weekend.

Chief Meteorologist Mark Nelsen


Evening Earthquake, East Wind, & The Next 10 Days

December 13, 2017

10pm Wednesday

Did you feel the quake last night?  The largest earthquake in our area in the past 2 years hit just a mile or so east of Scotts Mills.  That’s near Silverton.

A 4.0 sure doesn’t generally cause damage, except we did get one photo of a Christmas ornament fallen off a tree, and a tree fell off a bookshelf.  For some of us it was the first quake we’ve felt since that Spring Break Quake in March 1993.  This quake was centered within a mile of that one!  Check out all the 4.0 or larger quakes (over land) in our area since 1990

Let’s talk weather…

The easterly wind has spread back across more of the metro area this evening and gusts within the Gorge increased a bit too after a lull yesterday afternoon/evening.  Check out the past 9 days…ridiculous and the longest/windiest period we’ve seen since January 2009.

The very good news is that the airmass coming in with Friday’s cold front is MUCH colder overhead which will kill the inversion and kill the high pressure in Eastern OR/WA.  In fact by Friday afternoon I expect a breezy WEST wind through the other end of the Gorge.  Yes, Friday afternoon it should be calm at Vista House for the first time in 11 days!

The upper-level ridge over us will weaken a bit over the weekend, then strengthen again, but a bit farther west as we go through the next 7-10 days.  You can see the change from tonight’s 500mb map…

to 10 days out…Saturday of Christmas Weekend

During this time one or two cool systems will drop in over us from the north or northwest.  First will be Tuesday/Wednesday and possibly a 2nd late next week.   Neither will be all that wet, but bring showers and some mountain snow.  This setup will likely turn us a bit cooler as we head toward/into Christmas Weekend.  But models are in disagreement on exact placement of the ridge.  If it’s close to us we’ll just have sunshine and easterly wind again.  If it sets up farther offshore we’ll be significantly colder (arctic air) and that brings up the possibility of snow.  I’m leaning toward the first option for now.  It’s still a mainly dry pattern as I pointed out on my 12 Day Trend graphic this evening:

This is bad for ski resorts; we need new snow, and no significant snow is in sight for the next 6 days.  Christmas Break skiing/snowboarding will be limited, at least to start.  Hopefully that midweek system will produce at least a foot of snow.  We’ll see.

Chief Meteorologist Mark Nelsen

What Happened to “The Coho Wind”?

December 12, 2017

We’re going through what will likely end up as the strongest east wind event of the cold season…so let’s take a look back.  Do you remember the one winter when that wind had a name?

It was 20 years ago this month…

In 1997 the Oregon Chapter of the American Meteorological Society undertook an ambitious attempt to give the seasonal wind a name.  Why not? The dry east wind is called a “Santa Ana” in southern California.  Reno has the “Washoe Zephyr”.  Northern California gets a “Diablo” wind.  The Great Plains have a “Chinook” (although originally assigned to our warming southwest wind here).  But all through written history in our area the easterly winter wind has always just been referred to as “The East Wind”.  Local Native American tribes just called it an east wind in their distinct language.  And of course they were likely smarter than us, not camping near the west end of the Gorge in the winter.

A group of us figured it deserved a special name and ran a contest through the Autumn of 1997 to find a new name.  It was a huge collaborative endeavor with all local radio and TV stations getting involved.  Dozens of local and Pacific Northwest newspapers ran the contest or at least ran stories about it.  It was even mentioned by The Weather Channel.  You couldn’t avoid hearing about it at the time.

The volume of entries was far greater than expected; nearly 7,000! Pat & Sara Timm opened/sorted compiled the entries into a database.  Some were duplicates and the final 54 page listing contained 2,424 unique names.  We’re talking some really good names, but some real strange one too.  “Big Bad Momma”, “A Real Nipple Popper”, and “Devastating Doozy” come to mind as I peruse the book of names I still have in my file cabinet.

  • coho-alaska-salmon

Finally a group of maybe 10 AMS members got together and voted on the top 3, then a final one.  COHO was picked for a couple of reasons:  1) it’s the opposite of a CHINOOK wind (easterly vs. westerly), and 2) the COHO is known as a fierce and tough fish.  There may be other reasons but that was 20 years, 2 jobs, and 2 kids back in time for me.

For that first winter all of us regularly used the name and all seemed okay, but then the name fell out of use somewhat quickly.  As I recall by the following winter (1998-1999) the name was barely used.  I know I didn’t use it the 2nd or 3rd winter.  Why?  I found the people most affected by the wind seemed to hate it most and the people not affected much at all thought it was just fine.  As I recall (again, 20 years ago), I thought if people hate it and want to keep the current “name”, why should I be pushing it on them?  The Portland NWS and all other media stopped using the name as well.  It more  or less went into the history books.  Pat Timm used the name regularly in his weather column (The Columbian) for many years.  I just asked him about it yesterday, he said “I think it was a great name for a number of reasons…Just not enough support I think by the media to promote it. I think with social media now days and the Weather Channel naming almost every storm etc it would make it.”  Pat also says he would be interested in reigniting the name with a new generation of weather watchers.

In the past 24 hours I got an earful on a local (Corbett) FB group when I asked about the naming 20 years ago:  Jeanette- I never accepted Coho, it just was too polished or almost phony sounding. The wind is cold, harsh, and destructive and the only words that seem right are “The East Wind” .  Patrick– Those of us who live in the heart of it know it as The East Wind, a proper noun; not a common noun with a directional modifier.  Jeanie- They tried to force that name on us when we were so proud to live in “Corbett, Corbett home of the East Wind” (a song taught to all local school kids) . The music teacher had made a song about it which the grade school kids had performed many times. There were even T shirts printed with the East Wind blowing.  Catherine- One of the main reasons was that it was folks who didn’t live here or had ever experienced the East Wind who were trying to change the name!!  I think the best was from long-time resident Nev Scott.  She told me 15 years ago “It has always been The East Wind and always will be.  That’s it”  She wasn’t the type of person I wanted to argue with either!

Looking back 20 years, I think the problem may be that you can’t just force a new name onto an existing weather pattern with a known name.  Yes, it does have a name for those most affected; The East Wind.  Those other regional wind names likely came on gradually over many years as settlers move into an area.  Just my best guess on that.

What do you think?  Leave it as it is or try again in the age of social media?

Chief Meteorologist Mark Nelsen



Gorge Wind Storm Dying Down

December 11, 2017

9pm Monday…

The most damaging east wind storm in the western Gorge the past 9 years is finally ramping down this evening…slowly.

Pressure gradients from Portland to The Dalles have dropped dramatically from 12 millibars earlier to only 7.3 now.  Generally the higher the number the stronger the wind.


Windspeed has been slow to respond, but it should continue to drop tonight and be in a more manageable and typical 50-60 mph range tomorrow through Thursday.  Maybe even lighter if we get lucky.

We haven’t seen such high wind for several days since the January 2009 event.  Take a look at the past 7 days down at Rooster Rock:

Mark Gorge Wind 7 Day Gusts

I don’t have all the numbers from Corbett but they were similar, peaking around 80-88 for several days.  Keep in mind that in most winters at that location gusts above 75 are rare.  Last year I think it hit 80 or 82 once.

The Vista House wind sensor is gone.  It was beat up for a few days and then wasn’t there when I drove by this morning.  Probably out in Troutdale somewhere…note the last few wind reports around sunrise.  It made one last stand at 7:06am and then that was it.


The damage hit home today when a friend’s home was demolished by a fir tree last night.  While she was sleeping the tree crashed into her home,  impaling her in the abdomen.  She is still in the hospital and I pray for a speedy recovery.  I do know she’s a tough one!  I’ve always considered the east wind a nuisance (enough to move a couple of miles out of it) and somewhat interesting since it brings ice/snow, but that’s it.  This is the first time I’ve seen someone nearly die from that wind.  It gives you a different perspective as a forecaster…

This is the first time since that 2009 event we’ve seen lots of trees have falling for 3-5 days on homes, powerlines, and roads in a relatively small area up there.  It’s interesting windspeeds have NOT been exceptional in the Troutdale/Gresham area…just incredibly annoying.  That’s different from the 2009 event when the 60 mph gusts spread all the way out to Orient/Gresham/Troutdale areas.  But the weather setup has been the same otherwise:  A sharp upper-level ridge, extremely warm overhead airmass, and 10-12 millibar easterly gradient through the Gorge.

Looking ahead, the wind is still expected to stop Thursday night.  West wind will be breezy through the Gorge Friday.

Chief Meteorologist Mark Nelsen


2 Evening Questions: When Will the Wind Stop? What About Ice/Snow?

December 10, 2017

8pm Sunday

I was in 3 different public places today in the Gresham/Troutdale area.  The question was the same :  “I’m tired of the wind; I hate it.  WHEN is it going to stop?”

Answer:  Friday the cold east wind will be gone.   Bonus:  At least it won’t be quite as strong Tuesday-Thursday.


Today was day #4 of strong easterly wind across the central/eastside metro area.  That doesn’t count the previous day (Wednesday) when it wasn’t as strong out there, but everyone in the metro area saw at least SOME wind.  It appears there will be 3-4 more strong east wind days.  I drove by the Vista House wind sensor today; it’s bent a little more back against the building and far from horizontal.   There were plenty of people walking (stumbling & crawling) around though!

Wind Metro Peak Gusts East Wind


  1. Cross-Cascade pressure gradient is now the strongest we’ve seen so far for this event at 8pm.  Over 12 millibars from Portland to The Dalles.  The wind is just as strong now as anytime since Thursday and will remain in the same range through at least midday Monday.
  2. There have been power outages that come & go as more trees fall.  Expect more of those tonight and Monday, then fewer downed trees with more reasonable wind Tuesday.
  3. Peak gusts continue in the 70-80 mph range in Corbett area and 45-60 mph range in “upper” Troutdale.  I see two home weather stations have gone over 50 mph up there today.  I think this is the first time I’ve seen it gust above 80 mph on multiple days at that Corbett sensor that has been in place for 4/5 years.  This is an unusual event even for such a windy place.
  4. The weather we’ve seen this weekend continues through Thursday for all of us…valley sun, mountain warmth, & a mild coastline.
  5. There is no sign of a stormy weather pattern, lowland snow/ice, or flooding in the next 7-10 days.  Our slow start to storm season ’17-’18 continues.

Check out those morning lows in the calm locations…some of these are the coldest of winter so far:

Looking farther ahead…I’m confident we’ll be back to showers/rain/clouds/mild temps by Friday. Of course then the question is:


Answer:  A very small chance, it’s unlikely we get ice/snow this time around…whew!

All models are in great agreement that a cold front swings through here in Friday.  That reverses the pressure gradient quickly.  In fact I expect a mild & gusty WESTERLY wind through the Gorge by Friday afternoon.  This is not the usual ice-storm setup with a low coming up from the southwest.  In this case the front is sweeping in straight from west to east.  It wouldn’t be cold enough for snow anyway since the air overhead will be very mild.  At this point models show some weak precipitation arriving Thursday night and early Friday.  Assuming we don’t drop down to freezing Thursday night we’ll be too warm in the metro area for freezing rain.  Assuming precipitation makes it into the Gorge early Friday morning and the wind hasn’t reversed yet, there could be a very brief period of freezing rain out there (central/east Gorge only).  Lots of assumptions though.  I’d give the chance of freezing rain in the metro area about 10% right now and a 50/50 chance of something brief in the Gorge.  So again, this isn’t the setup for an ice/snow event in our area.  Don’t change any of your plans for Friday.  It’s most likely we just have some light rain and Friday ends up around 48 in the afternoon.

Beyond that some snow will likely fall in the Cascades Friday (a little) and then rain or a mix of rain/snow at the ski resorts over the weekend.  Another shot of snow is likely the early part of NEXT week and then…the bad news…models are pushing another warm ridge overhead as we head into Christmas weekend.  That’s almost two weeks away.  Here’s the ECMWF ensemble average of 500mb heights on Christmas Day.  Don’t place bets on a snowy Christmas!


Chief Meteorologist Mark Nelsen

High Winds, Cold Nights, & Another Dry Week

December 8, 2017

6pm Friday

For such a “boring” weather pattern the details for the weather geeks have been fascinating the past 24 hours.  Consider that:

  1. Temperatures soared into the 50s on Mt. Hood today…55 at Timberline Lodge!  In fact a few spots in the western Cascade foothills were in the 60s.
  2. Meanwhile, as expected, temperatures in the lowlands have continued to drop as cool air becomes established in the valleys & Gorge under an inversion.  Today was the coldest day so far this winter at PDX.  That’s right, you need to go UP at least a thousand feet to warm up!

3.  That’s due to the end of the mild downsloping wind off the Cascades.  Now all that air moving from east to west across the state has to squeeze through a very shallow layer under the inversion through the Gorge.  Check out the metro peak wind gusts…all areas west/south/north mainly calm…

4. Yet within the Gorge and far east metro the wind has continued to pick up.  The wind at Corbett has gusted above 70 mph every 10 minute period since 3pm…that’s unusually strong even for them.  The raging wind continues through the weekend.

I notice temperatures in the mountains will probably warm a few more degrees by Sunday as 850mb temps rise into the mid teens.  The strongest wind event I remember in the Gorge was when 850mb temps got up around +18 in January 2009.  That really squeezes the air down and speeds it up.  By the way, I drove by the Vista House wind sensor at midday.  It looks beat up, bent down and back a bit, which accounts for the “low” wind speed there the past two days.  Combine the wind and cooling airmass coming through the Gorge and it feels like mid-winter out there.  Here are the 6pm windchill values.

Ice has also begun to form on Gorge waterfalls.  It will be a great weekend to check out the wind, waves, and icy waterfalls in the Gorge.  I found this just on the road to Vista House at midday:

And the river will look like this pic from Kirk Mattila.

With such a dry airmass and our long winter nights, temperatures in calm areas have been plummeting.  Check out the mid 20s in many areas this morning.  Expect more of the same the next few days:


This general pattern continues through about Wednesday next week.  That will be our 10th dry day in Portland.  However it appears things will be changing after that time.  The most reliable model and its ensembles show onshore flow (and the end of the cold east wind) Thursday/Friday next week as the strong upper-level ridge flattens and systems go by to our north.  This happens to be the one pattern that can minimize or eliminate the threat for snow/freezing rain as we go back to milder weather.  We’ll see how it pans out, but we might be back to gray and drippy conditions later next Thursday or more likely Friday west of the Cascades.

Beyond that, models are in disagreement whether we go into a cooler/showery pattern with the big ridge moving farther west offshore, or stay in milder westerly flow with weak ridging.  The net effect doesn’t appear to be a return into a soaking wet November-like pattern.  Note the ensemble average precipitation from the ECMWF is only 1″ in the week leading up to Christmas.

So enjoy at least another 5 days of dry weather with sunshine, then most likely we’ll turn at least a little wet and much grayer late next week.

Chief Meteorologist Mark Nelsen

Here Comes The Wind!

December 5, 2017

7pm Tuesday

I mentioned in Sunday’s post that we’re in this weather pattern for the long haul.  Now, two days later, all models are keeping us dry or almost dry through the beginning of many school’s Christmas Vacation.  That’s Saturday the 16th for many kids.  Some schools are waiting one more week though…it’s a bit staggered this year.   Regardless, I’m quite confident the weather pattern will be VERY slow the next 10+ days.  Check out the ECMWF model’s ensemble precipitation forecast.


It looks extremely complicated but it’s really not.   Each horizontal line on the upper half of the image is just one of 51 ensemble members; a slightly different version of the same model run.  We’re looking at 24 hour rain/snow totals.  Time goes from today on the left side to two weeks from now on the right side.  The bottom section is just the average of all of those ensembles.  Two key points here  1) The first decent rain chance isn’t until Friday/Saturday the 15th/16th.  2) Very few members show a rainy pattern and 3) A few produce no rain at all through the 19th/20th.

High pressure is developing east of the Cascades and will strengthen as cool air deepens in the lower elevations over there…

Mark EastWind ColdAir Builds Basin

That cool/dense air can only move through the Cascades in the Gorge if it’s less than 3,000′ thick.  That layer of cool air gets squeezed down much thinner as it moves into Western Oregon.  The wind accelerates as it moves from Cascade Locks to the Troutdale/Camas areas.  This pattern will continue as long as the upper-level ridge sits along the West Coast…through the next 10 days.  So you folks in the western Gorge and eastern metro area have a long period of screaming easterlies ahead…sorry!  This will be what we call a “gap wind” event where the areas downwind from the Gorge get the wind, the yellow areas on the map:

Warnings Gorge and Metro East Wind

Other parts of the metro area stick with mainly light wind.  The strongest wind will at the western “exit region” of the Gorge.

Warnings Gorge and Metro East Wind2

Peak gusts there should generally be in the 60-80 mph range the next few days.  Of course if you’re right on an exposed point (Crown Point), the wind can be even stronger.  This is the setup where you can easily record 100+ mph gusts on the steps at Vista House.  Enjoy, but bring a ski mask and a thick jacket!

Temperatures will be gradually cooling at the lower elevations the next few days (no more 50 degree highs!) while the mountains warm up as the upper-level ridge builds overhead.

On a brighter note, today’s sunset is the earliest of the year…it’ll be 4:27pm for the next 10 days.  By New Year’s Eve we’ll gain 10 minutes of daylight in the evening.  Summer isn’t far away right?

Chief Meteorologist Mark Nelsen