December 27th wind storm recap

December 29, 2022

11pm Thursday…

I was off on holiday/vacation the past 4 days. After a quick Christmas morning post on social media, I pretty much checked out through yesterday. During that time the thaw finished, downpours commenced, and we had a windstorm. This post is mainly just a recap. That way in the future when I look back this event I’ll see what happened meteorologically.

It was VERY tough to get rid of that cold air. Sure enough, models pushed the cold easterly flow out too quickly last Friday/Saturday and we warmed very slowly on Christmas Eve. That easterly flow continued, although above freezing, through Sunday and Monday. Some spots in the valley hit 60 or higher on Christmas Day in the southerly flow!

(kptv)

By the way, at this point we’re experiencing the coolest December since 2016. That’s a combination of consistently cooler temps and the 3 days of REALLY cold stuff! Still, Portland did not make it down into the teens this time. I think it’s been about 6 years since Portland has dipped below 20! There’s still a chance for another 6-7 weeks or so of course.

As for rain, what a soaker! Between 4-5″ rain in Portland during the 4 day period ending Tuesday the 27th

(kptv)

This rain played a large part in the destructive windstorm on Tuesday. I’ve always noticed our windstorms are more “productive” when we have soaked/saturated soil at the same time. On Tuesday morning, a well-forecast “bent back occlusion” moved inland across southern Washington and northern Oregon. Here’s the WRF-GFS surface forecast for 10am Tuesday, just 6 hours after model initialization time. A main 973mb low moving toward the northern tip of Washington, while a secondary trough or possibly closed surface low moving toward Astoria. Both were beginning to “fill” or weaken.

(kptv)

This is a sort of “double-barrel” low. Radar confirmed this DID occur, in fact the surface “trough” moving onto the coastline sure appeared to be a closed area of low pressure.

(kptv)

That low was weakening while moving inland. Here’s the 1pm forecast

(kptv)

Peak wind for many of us occurred around this time (Noon-2pm). as the weakening low passed by to the north of Portland, tightening pressure gradients. Then by 4pm, the dying low had passed over and east of the Cascades

(kptv)

At this point wind was peaking over the central/eastern Gorge, valleys around Mt. Hood, and north-central Oregon. This DID finally wipe out the last of the cold air as temperatures finally jumped into the 40s in Hood River and The Dalles.

The peak gust of 48 mph at PDX was the strongest southerly wind there in almost two years. We really didn’t have any windstorms (from the south) last winter. Just about all official gusts were in the 45-55 mph range in the lowlands. Here are metro gusts, note Troutdale’s gust is from the east as the storm approached.

(kptv)

Valley wind gusts

(kptv)

And then those strong west/southwest gusts in the Gorge and Hood River Valley

(kptv)

70-80 mph on the river? Must have been quite a sight to see the spray blowing across the water like a hurricane!

Unfortunately there were at least 3 incidents in which trees fell on highways, hitting vehicles and/or causing collisions which led to deaths. East of Seaside on US26, east of Government Camp on US26, and I-84 near Bonneville Dam.

One part of the storm that’s most surprising is the amount of damage and power outages; both seem to be well beyond what we would expect with 45-55 mph gusts (for most of lowlands). To me it appears the damage is more like what we’d see with gusts 55-65 mph. This has happened in the past, and will happen again. Extremely wet weather saturated soils, allowing trees to uproot more easily. Portland alone picked up over 4″ rain in 4 days

(kptv)

You can see the effect on outages. LOTS of us lost power; I was lucky and only out 14 hours. At this moment (10:30pm Thursday), 1,500 of you are still out of power according to PGE’s website. This storm was similar in scope to January 2021, but not as bad as the April 2017 windstorm.

(kptv)

So, lots of rain, then strong wind = plenty of falling trees. We were fortunate that surface low was weakening instead of strengthening as it moved onshore and through SW Washington. Some of Portland’s strong storms (much stronger than this one) have come from that setup.

That’s it for now, I see uneventful weather this weekend as 2022 rolls into 2023. No storms, cold, or snow over the next week as the jet stream aims mainly at California.


Ice storm in progress as metro area remains frozen through Saturday morning

December 23, 2022

11am Friday…

Unfortunately the forecast is working out as expected this morning.

WHAT’S HAPPENING NOW

  • Cold air is stuck in the lower elevations of NW Oregon and SW Washington with temperatures below freezing anywhere inland from the coastline.
  • All of the coastline has warmed above freezing
  • The Cascades are warming quickly and even Government Camp will warm up to around 40 the next few hours. Santiam Pass jumped from 20 to 40 between 6 and 7am! Cold air is becoming shallower. Silver Falls State Park is in the mid 40s at 1,600′ elevation.
  • Roads are covered in glaze ice in most of the metro area, except far eastside where they are mainly dry or covered in ice pellets
  • Freezing drizzle or rain showers are roaming around the area
(KPTV)

The metro area is locked in the cold air

(KPTV)

This setup continues through the evening hours as showers taper off. Tonight should be mainly dry, except for spots of freezing drizzle.

Last night and this morning wind in the western Gorge and extreme eastern part of metro area was about the highest it ever gets. Troutdale airport gusted over 50, which is rare. I see a gust to 88 at Corbett school, which I think is the highest observed there in the past 15 years

(KPTV)

Yesterday the Vista House wind sensor disappeared. I mean, it really just ripped off the building. You see the observations suddenly go to zero. R.I.P.

(KPTV)

WHAT’S AHEAD

  • All areas from Salem to Longview (including metro area) stay locked in ice through sunrise Saturday
  • During the day, temperatures warm above freezing EVERYWHERE except areas from about I-205 eastward to the Columbia River Gorge, from just north of the Columbia river down to about Powell/Foster road areas. This will be the last place to thaw…most likely not until sometime after 3pm
  • Warming will be dramatic in the valley, west metro, south metro, and SW Washington tomorrow midday and afternoon. Your location could jump from 32 to 55 in an hour or so as south wind arrives! In these areas, road conditions should be MUCH better late in the day and into Christmas Eve (after sunset)
  • This means that much of the metro area will be finished with the ice storm midday/PM tomorrow
  • Moderate to heavy rain falls tomorrow morning through early afternoon. The result will be the heaviest ice glazing so far in the areas still frozen. That’s most likely central/east metro and into the Gorge. But even in those areas, temperatures should rise above freezing at some point Saturday evening. Assume roads will stay iced over through much of the night tomorrow night out there.
  • Finally, Sunday we’ll just see light showers and temperatures above freezing all day. A cool easterly wind returns, but with temperatures warm enough to avoid more freezing rain
  • Columbia River Gorge remains frozen east of Troutdale through Sunday, then a thaw commences (slowly) on Monday.

The next 24 hours is crunch time for weather forecast models. They’ve been pushing warm air in tomorrow and most even think we are above freezing by later tonight in the entire metro area. That’s not happening. As long as easterly flow out of the Gorge continues, we stay frozen. Here’s one example. GRAF short range model thinks we’re around freezing by this evening in Portland

(KPTV)

The Euro has been very insistent pushing southerlies into the metro area by midday or early afternoon tomorrow. I do see about 4 millibars southerly gradient from Eugene to Olympia by 4pm, with easterly gradient supposedly down to 3 millibars through the Gorge. That COULD get rid of the metro cold. It’ll be quite a battle between the retreating cold airmass and surging southerlies, but I’m playing it conservative and assuming it won’t happen for east metro until evening. That’s why we’re forecasting significant ice glazing east metro tomorrow.

(KPTV)

If we get lucky, it’s right. Who’s going to complain that it warmed up “early” if that’s the case? So maybe we’ll get a little Christmas miracle tomorrow evening in the form of warm temperatures and southerly breezes!

That’s it for now, we’ll be on the air at Noon, 4pm, 5pm, 6pm, 8pm, 9pm, 10pm, and 11pm this evening so you can catch me there


Noon Thursday Update: Coldest day in years in Portland, precipitation arrives later

December 22, 2022

12:15pm Thursday…

Everything is proceeding according to plan as they say.

Today is a rare sub-25 degree day in Portland. In fact we haven’t seen a day in the 20s since January 2017. Couple that with east wind gusts 35-50 mph and it’s bitterly cold out there (by Portland standards). If I read the numbers correctly, we’ve only seen 4 days with a high temp at/below 25 in the last 20 years! It’s cold…

(Wx Blog)

Along with that, the wind is a big story. Peak gust is 46 mph at PDX so far, with some of the bridges seeing gusts to 50 mph. Rough driving, and a few trees are down here and there. The pressure gradient, the difference in pressure from The Dalles to Portland, is at 15 millibars! The highest I’ve ever heard of was an 18 millibar gradient during the east wind storm December 24th, 1983. I don’t think I’ve seen 15 millibars in my career, but maybe I’ve forgotten one. Regardless, very strong high pressure is squished up against the east side of the Cascades and wind is likely gusting well over 100 mph right now on those Vista House steps…at 15 degrees.

(Wx Blog)

Precipitation is slow to arrive, as we’ve expected. Expect spots of flurries or ice pellets to appear in the next few hours, but my feeling is that anything significant that would freeze on roads and ice things up (liquid rain) will wait until after 5pm. That’s at the earliest. Models are indicating the transition to liquid rain could even wait until 7pm or so. That’s because it takes time for the warmer air to work in overhead. It needs to go well above freezing up around 3,000-5,000′ to change those snowflakes into raindrops. There will be a period this evening when we get ice pellets. That’s when this surface cold layer is so deep that the raindrops refreeze on the way down. They make that little “clinking” sound when they hit the ground, your car, or your head.

Then from 7-8pm or so onward, it’s ALL liquid rain through the rest of this event. Our forecast thinking hasn’t changed…up to 1/3″ ice glazing everywhere in the western valleys overnight through tomorrow afternoon, and a few spots may hit 1/2″ by Saturday sunrise.

ALL VALLEY LOCATIONS FROM LONGVIEW TO SALEM SHOULD STAY FROZEN UNTIL SUNRISE SATURDAY

Models are still in quite a bit of disagreement over when we switch to the warm south wind. So we’re sticking with the reliable “we’ve seen this before” forecast. That means cold air very stubborn to give way to those 55 degree southerly breezes! But that dramatic warming should finally happen Saturday for everyone except inner central and east Portland, and of course the Gorge.

The heaviest rain of this evening is forecast ON Saturday. So areas that don’t thaw Saturday could pick up another 1/2″ of ice glazing. That makes me think this could be a 1″ ice storm in East Portland east of I-205, assuming you folks don’t warm above freezing until late Christmas Eve (maybe well after dark). We will see. This European model forecast thinks all of Portland metro will be above freezing by Saturday morning. It’s warming us too quickly and doesn’t account for the extra freezing rain Saturday. But it’s producing plenty tonight through Saturday morning (when it thinks we’re done)

(Wx Blog)

That’s it for now…I’ll be on TV all late afternoon through 11:30pm! And we’ll try to post updates to our weather app regularly this afternoon and evening too. We do have a separate weather app, in addition FOX12 OREGON news app. You can find it here:


Ice storm for I-5 corridor and metro area Friday, then warming for some of us Christmas Eve

December 20, 2022

7pm Tuesday…

Today was just about the warmest we’ve seen so far in December with temperatures around 50. As the front moves south of us this evening, the rain shuts off, skies partially clear, and colder airmass returns. Expect temperatures down around freezing late tonight and any wet roads will freeze. There’s a good chance some roads dry though before turning icy. Still, be careful during the morning commute!

Tomorrow will be a pleasant, cool, and crisp December day with lots of sunshine and not much wind most of the day. Around sunset, cold modified arctic air will arrive on a gusty northeast wind. This will be the cold airmass that’s been bottled up in Washington the past few days. By Thursday morning the east wind will be blowing hard in Portland and temperatures will be the coldest we’ve seen so far this season…down into the lower 20s! That’s a wind chill in the single digits, something we haven’t experienced in a few years. Assuming we don’t get above 29 Thursday, that will be our coldest day since January 2017.

Thursday will be dry until sometime in the afternoon as a few flurries start to fall. Then as we head into the evening hours the flurries change to ice pellets and finally freezing rain, depending on location in the metro area. By Friday morning the entire metro area and everywhere else west of the Cascades will be a frozen, icy mess. More freezing rain falls through the day Friday and that means we’ll basically be in ice storm conditions all day long Friday. Assume all roads will be frozen the entire day. Travel will be very difficult in the entire I-5 corridor.

Saturday should dawn with the same frozen conditions for just about the entire I-5 corridor and metro area. Freezing rain continues to fall at times Saturday in much of the metro area. But at some point later in the day a warming southerly wind should push all areas except central/east metro above freezing. As the sun sets Christmas Eve, a general thaw should be in progress except in those areas. But many areas could be out of power due to thick ice accumulation in the 48 hours before that time.

Rain (or freezing rain depending on location) will continue at times Saturday night through Sunday. The cold east wind should be mainly gone by Sunday morning, so expect ALL of the metro area to thaw Christmas Day. Temperatures in some areas could approach 60 degrees…it’s a very warm airmass overhead through the weekend.

AT THE COAST

The first area to thaw will be the northern Oregon and southern Washington coastline. Expect only a brief period of freezing rain Thursday evening and night, mainly NORTH of Lincoln City. The southerly wind takes over Friday and temps rise above freezing even way up on the Long Beach Peninsula by midday Friday.

(kptv)

IN THE VALLEY & NORTH TO LONGVIEW

This will be the 2nd area to warm up…most likely not really starting until Saturday. As we’ve seen in past ice/snow events, a very thin layer of cold air will remain down to about Albany/Lebanon for freezing rain off/on Friday. As long as wind remains northerly (through Saturday morning), temperatures won’t warm much. This is how it looks for these areas, including north Clark County to Longview. Most likely frozen from tomorrow night until Saturday morning. Now keep in mind the freezing level Saturday will be up around 7,000′ or so. When the south wind DOES arrive, it’s going to be a dramatic warming! Spots could go from 32 to 55-60 in just an hour or two! Up to ½” is possible from Thursday evening through Saturday morning in the valley, luckily nothing like the 1-2″ in spots during the February 2021 event. I think Christmas Eve (after sunset) should see pretty good travel conditions away from the Portland metro area (both north and south)

(kptv)

PORTLAND METRO AREA

As always, since this area is most exposed to cold air pouring out of the Columbia River Gorge, it’ll be the last to go above freezing.

– West of the West Hills, and south of about a Downtown to Clackamas line, temperatures should rise above freezing at some point Saturday. It could be a dramatic warming in those places too…32 to 55 in a short period of time! Clark county, away from the Columbia River, should see at least some thawing Saturday too, even if it takes until later in the day. For these areas, it’s possible you’ll be able to drive around comfortably after sunset on Christmas Eve. We’ll see how that works out.

– Downtown east toward the Columbia River Gorge? I have a feeling this part of Portland could stay frozen until Sunday morning, or at least until sometime overnight Saturday into Sunday. The problem is that A LOT of rain will have fallen down into the subfreezing air from Thursday night through Saturday evening. Hopefully it won’t be like December 1996, but I could see a lot of icing with this event, maybe well over ½” or even an inch of icing. This could be a big ice storm for the east metro area with at least an inch of icing and widespread power outages. Merry Christmas…

(kptv)

COLUMBIA RIVER GORGE

There’s no way the Gorge will see thawing through Christmas Day, so this is a 3+ day long event. Snow at first, and I-84 should “just” be snowy for the first part of Friday. Then ice pellets and finally a change to liquid rain freezing on contact later Friday. From that point through Sunday, it’s all freezing rain in the Gorge. Quite a “Merry No Power Christmas” for some of you!

(kptv)
(kptv)

WHY IS OUR FORECAST DIFFERENT?

Apparently our forecast looks much different than other forecasts for Friday and Saturday, which is a little unusual. Significantly colder and hanging onto freezing rain through Christmas Eve for at least some of the metro area.

(kptv)

Usually I’m the one downplaying snow chances with my “warm bias”.

But this is a setup I’ve seen time and time again, even the highest resolution models scouring out the thin cold layer too quickly. Sure, it’s better than 20+ years ago, but still issues. Check out this gem from a blog post in December 2016. It’s almost like Mark from 6 years ago is leaving me a message… “After countless events like this, I should have realized (again) that unless models forecast a significant southerly wind push up the valley, or a decent westerly wind in the Gorge, temps won’t warm up quickly at all” Blog post is here: https://fox12weather.wordpress.com/2016/12/09/cold-air-stuck-in-gorge-ice-snow-continue-tonight/

During that event, which wasn’t even as cold as this one is forecast to be, it only warmed up 2-3 degrees in a 24 hour period. So…we’re going very conservative with the warming Friday through Saturday, and thinking the Gorge stays frozen. Even the ECMWF model has 9 millibars easterly pressure gradient through the Gorge Saturday morning, and still 5 in the afternoon. The cold air will still be blasting into the east metro area on Saturday. Only on Sunday does it briefly go flat, but then returns to 5-6 millibars easterly Monday and Tuesday. I see a long duration ice storm out there with I-84 potentially closed for several days over the Christmas weekend.

That’s it for now…enjoy the dry weather tomorrow!


Widespread freezing rain (ice storm) likely heading into Christmas weekend

December 19, 2022

1pm Monday…

The timing couldn’t be any worse could it? I know LOTS of you have plans for either road or air travel late this week and into the holiday weekend. Well, it appears the biggest winter storm we’ve seen since the Valentine’s weekend snow/ice storm in 2021 is headed our way. This includes not only the Portland metro area, but likely even (briefly) reaching out to parts of the coastline and down into the entire Willamette Valley. And the Gorge…well, most likely not much will be moving there Friday through Christmas Day. It’s still 3-4 days out, but our models are in excellent agreement on timing and impacts. First a summary for the TL:DR folks

Summary & Timeline

  • Cold arctic air pours south into the northern half of Oregon Wednesday night and Thursday. It’ll be relatively shallow cold air west of the Cascades, less than 2,000′ deep; much deeper east of the Cascades in northern Oregon.
  • Thursday will be bitterly cold in the Portland metro area. Gusty east wind and highs only 25-30! We haven’t seen that in two years. Wind chill down in the single digits and teens all day. Gusts could top 40 mph. Yet we remain dry through most of the daylight hours. At some point late Thursday (sometime between early afternoon and midnight), snow or ice pellets begins falling. Exact precip-type is TBD, but my gut feeling is that we’ll only see a brief period of snow if we get it.
  • Between Thursday evening/night and Sunday, several waves of rain will pass overhead. Snow levels jump to 7,000′ and above through the weekend! But the stubborn thin layer of cold air persists in the Willamette Valley, metro area, and Gorge. These events almost always proceed in the same order. As cold air thins in the valley & coast first, freezing rain (liquid rain that freezes on contact) changes to rain as temps rise above 32 degrees. At some point west/south metro go above freezing, then east metro rises above freezing. This process should take about 2 days in this pattern. Then, finally, the Columbia River Gorge starts a thaw. That final step likely won’t occur until at least Christmas Day (Sunday), or even Monday! This setup is “perfect” for a major ice storm, if not in the valley or metro area, for sure in east metro and into the Gorge.
  • So…expect widespread freezing rain Thursday night and Friday, then more freezing rain Friday night and Saturday in much of the metro/Gorge (only). Then by Sunday hopefully just about all areas west of the Cascades will be above freezing and Christmas can proceed (with lots of leftover power outages). The Columbia River Gorge will be locked up snow, then ice from Friday through Sunday. Melting may not occur until Monday there. Plan on staying in place out there. Although possibly Friday could be mainly snow east of Multnomah Falls = better.
  • Assume much of the I-5 corridor could “shut down” driving-wise Friday, for one day. Then there’s a decent chance at least half the metro area is still frozen through Saturday. Maybe roads are much better west/south metro…maybe. Worst-case scenario is that it’ll be hard to move in much of the Portland metro area all of Friday and Saturday with lots of freezing rain and power outagesA memorable Christmas ice storm. Best case is that most of the I-5 corridor is in good shape by midday Saturday and ice storm conditions are only confined to east metro areas near the Gorge. That’s best case.
  • Flying Friday or Saturday? Well, be nice to those folks working at the airport because their job is now much tougher. That could be a mess

IF YOU HAVE A CHOICE, TRAVEL ON THURSDAY. It should be dry throughout the region

Details

It’s great to see models in really good agreement 4-5 days ahead of time. By Saturday evening it was becoming obvious that something big is on the way late this week. The upper-level pattern remains the same with a cold upper trough just to our north.

(KPTV)

It sends a little upper-level system (shortwave trough) through the Northwest late tomorrow and Wednesday morning

(KPTV)

Then by Thursday evening, a warm southwesterly flow is developing in the upper atmosphere. Snow levels are going through the roof as a system approaches. This warm/wet pattern will continue through much of next week too. Best skiing is in the next 48 hours!

(KPTV)

Here’s the problem, at the surface that Wednesday system moves by and allows cold arctic air to pour southward. By 7am Thursday, this model (likely a little too cold), shows temperatures around 2,500′ at ZERO over Hood River and The Dalles. We haven’t seen air that cold in a few years, that’s colder than with the February 2021 event. Now I mention it’s “too cold”, but Thursday has looked the same on maps/models for a couple days.

Wx Blog Images
Wx Blog Images(KPTV)

That cold air will pour through the Columbia Gorge Wednesday night and Thursday, blasting us with strong wind, temperatures in the 20s, and bitterly cold windchill. It also filters onto the north coastline and south to Eugene. Notice the strong easterly wind 50-60 mph just a couple thousand feet above the surface on the WRF-GFS model…for Thursday

(KPTV)

Most models have precipitation arriving 4pm-10pm Thursday. That’s just a first guess. So the first snow/ice pellets/freezing rain MAY impact the Thursday evening commute. If it starts as snow, it can’t last long because forecast soundings imply warming overhead happens quickly. This GEM sounding from 7pm Thursday shows the warmer layer arriving overhead around 3,000-5,000′. “Warm” means above freezing in this case. I don’t see any model producing more than 1/2″ snow before the changeover.

(KPTV)

One big question is how much precipitation do we get Thursday night through Saturday? Models are all over the place so we’ll have to wait and see. Generally anything over 1/4″ ice glazing in the Willamette Valley and much of metro starts to cause power outages. Once it hits 1/2″, then things are getting real with lots of limbs down and outages. Here’s the Euro’s guess. This is by midday Saturday. Icy. Then of course there would be more ice later Saturday and Sunday IN the Gorge where temps likely remain below freezing.

(KPTV)

What Could Change the Forecast?

The number one element that could throw things off is if models are handling the arctic airmass to our north badly. If Portland is only 35 on Thursday/Friday instead of 28, that’s a very different story and much of the Willamette Valley and coastline could avoid freezing rain. We’d have a shorter episode of freezing in the metro area too, maybe Friday only. For now I’m not seeing that, especially since the dependable models have handled the southward progression of arctic air today quite well. It has made it into north-central Oregon and west of the Cascades down to Seattle. It will actually be pushed back out of those areas tomorrow as southerly wind takes over for a day, but then it’ll be pulled back south Wednesday as mentioned earlier.

Lots more details to come this week. I’ll be at work every day through Friday and we have all our morning/evening shows on TV. Stay tuned!


Dry days continue through Saturday, but watching cold/snow possibilities for next week closely!

December 13, 2022

It’s that time of year…we are now in “primetime” for snow/ice west of the Cascades. The two months from mid-December to mid-February? It’s peak season for region-wide cold blasts or day-long ice/snow storms. It’s rare for either of those to happen outside of this time…west of the Cascades. Models HAVE been teasing us for at least 5 days, hinting that something MIGHT be up for early next week. Some weather apps or forecasts elsewhere would have you think some sort of big freeze or snowstorm is on the way. But, for now, I’m not seeing that. You’ll notice our FOX12 Weather App just has some mixed showers in it for Monday and no “freeze”. For now…

First, we are in a relatively pleasant period for the rest of the week. At one point (last week) it appeared a cold airmass would descend south on the east side of the Cascades, giving us a long period of very cold east wind. That has instead turned into just two days of “normal” gusty easterly wind blowing through the Gorge and east metro areas. That’s Thursday and Friday. At least that will clear out the fog/clouds tomorrow afternoon, leaving us with sunny days both Thursday and Friday. We’ll be staying dry through Saturday too. That’s due to a very strong upper-level ridge sitting over the eastern Gulf of Alaska. It’ll be there through Thursday, blocking all wet Pacific weather systems.

A change arrives this weekend, the ridge “retrogresses” or backs up. Then it amplifies northward into Alaska. That leads to a sudden southward plunge of cold polar/arctic air through western Canada,

By Sunday, this leaves very cold arctic air poised just north of the US/Canada border. This setup can bring snow down relatively close to sea level, but we don’t get a big freeze or guaranteed snow. That westerly flow overhead leads to light (rain) showers Sunday with onshore or southwesterly flow at sea level = mild.

What happens BEYOND Sunday is still up for debate, but models are definitely leaning toward WARMER compared to previous models runs the past few days. The main issue is that (as of this evening) no model is plunging that cold upper-low straight south into the western USA. That would give us a regionwide arctic air outbreak (2013, 2009, 1998, 1990, etc…). In fact, if the upper low doesn’t move any farther south than the position above, that means no arctic air makes it down into Oregon! Notice it still looks about the same on this model (morning ECMWF run) for Tuesday compared to Sunday; not much has changed since the cold low hasn’t moved.

We can get snow to sea level in this pattern, but that’s with onshore flow and we end up with something like we had last Christmas Day. Sloppy/heavy wet snow showers, especially on the hills. For the geeks, we need 850mb temperatures (Celsius) down around -7 to -9 for lowland wet snow in this pattern. Right now I see -5 to -6 Sunday (no snow), and -4 to -6 ensemble average ECMWF temps Monday (no snow). High temperatures those days would be in the 38-45 degree range. Models are hinting an organized wet system could move onshore late Monday or Tuesday though. The Euro has a slightly deeper trough and keeps the solid precipitation south of us late Monday and Tuesday AM. That’s something to watch because a rapidly deepening low pressure center close to a very cold airmass can lead to issues forecast-wise.

What about Tuesday? You’ll notice the last day of our 7 day forecast looks similar; cool, but not really COLD. I’m ignoring this morning’s very cold ECMWF model run. It pushes cold a bit farther south than other models; PDX gets -11 or -12 850mb temps. Unfortunately (or fortunately for my forecasting sanity), the ensemble average is only -4! That means most of those ensemble members aren’t nearly as cold and that’s the better forecast option. Not as fun, but a good move.

Based on all this, our 7 Day forecast, both on TV and app, looks like this:

We could easily get through the next 7 days with no sticking snow. For that reason I haven’t called any of those days a “Possible First Alert Weather Day” because at this point I don’t see any weather that would disrupt your plans in the lowlands of NW Oregon and SW Washington.

That said, keep in mind that cold arctic air will be just to our north Sunday through Tuesday. A slight change could bring moisture onshore and pull at least a bit of that cold air southward or westward through the Gorge. I’ll be watching closely!

…Chief Meteorologist Mark Nelsen


What happened to the “Coho Wind”?

December 6, 2022

Do you remember the ONE winter when that cold east wind that blows out of the Gorge had a name?

It was 25 years ago this month…

In 1997 the Oregon 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 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.

But 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. This is the only time in my career I’ve seen these groups get together on one project. 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 of Felida opened, sorted, & compiled the entries into a database.  Some were duplicates, but 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. I notice the paper is starting to turn just a bit yellowish. Uh-oh, that means I’m aging too.

Finally a group of maybe 10 AMS members got together and voted on the top 3, then a final one. I still remember it was the backroom of the McMenamins on Broadway. Talk about “backroom deals”! 

The name 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 25 years, 2 jobs, and 2 kids back in time for me.

Coho Blog

What happened?

For that first winter all of us regularly used the name and all seemed okay, and I mean TV forecasters, the National Weather Service, and newspapers.

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, 25 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 Eye weather column (The Columbian) for many years.  I asked him about it at around the 20 year mark. 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.

Back at the 20 year mark I got an earful on a local (Corbett) Facebook 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 20 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 25 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?