Quick Storm Wrap and a Look Ahead

January 6, 2019

6pm Sunday…

Well that was a quick little storm wasn’t it?  But at the height of it around 11pm-midnight there were 45,000 or so PGE customers out of power; the largest number in Clackamas County.  A huge transmission line failed in Vancouver leading to most of the outages up in Clark County.   You can see how that 45,000 number compares to big windstorms like 2006 and 1995

mark pge poweroutages lengthoftimeout

 

The peak gust of 54 mph at PDX around 11pm was the highest since the April 2017 windstorm.  Yes, that was a weirdly out-of-season storm wasn’t it?

wind metro peak gusts today

Looks like all the official airport observing stations in the North Willamette Valley were between 44 and 54 mph.  To be honest, a bit weaker than I expected.  I figured we would see a few more 50+ gusts at Hillsboro and Troutdale or Vancouver.  Close enough I suppose.  The stronger wind gust models were right on, including the trusty WRF and ECMWF.  Timing of wind arrival was excellent except for the slow GEM.   Our RPM was somewhat abysmal with respect to intensity (surprise!).  That’s the model used by The Weather Company (IBM) formerly WSI.  They supply weather graphics/computers to three of four local TV stations (including FOX12).  We show that model for future cloud/rain/snow graphics but do have the ability to show ECMWF, GEM, & GFS as well if needed.  Luckily it’s about to be replaced by IBM’s MPAS & Deep Thunder modeling.  That should do better, we’ll see.

Looking ahead, we are in a chilly airmass with sticking snow levels down to 2,000′ or a little under tonight and tomorrow morning.  This is one of only two times we’ve seen it that low this season!  What a mild winter… Showers end tomorrow morning giving us a dry Monday afternoon.  The pattern the rest of this week is very mild with occasional light rain as a deep storm wraps up offshore tomorrow and Tuesday, then the leftovers move inland Wednesday.

Another mild wave moves inland Friday night and next Sunday.  Note the very high snow levels much of this upcoming week; passes remain clear after tomorrow night.

ecmwf snow level from 850mb temps long term

Looks like we hit the snow jackpot just in time for Christmas Break; kids are all back in school tomorrow and then snow conditions are going downhill.

Speaking of snow, I see nothing remotely close to lowland snow the next 10-15 days, which will take us to the 3rd week of January.  Check out ECMWF & GFS ensembles for snowfall; I’ve chosen Aurora so it picks a grid point in the middle of the valley…nothing shows up from any ensemble member!

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ECMWF ensemble forecast highs/lows shows the mild pattern next 15 days,

kpdx_2019010612_eps_min_max_15

I’ve mentioned this earlier in the year, but this season reminds me of El Nino year 2002-2003 so far.  Unusually dry in November then decent snow in mid-late December, now the pendulum seems to want to go a bit warmer.  Although we’ve avoided any sort of big Cascade meltdown from a Pineapple Express.  You can read about that Cascade snow season in the Ski Mountaineer Web Site.  Quite a detailed account of several snow seasons on that site.  Looks like a lot of work; someone got tired of writing after 2006!

Now we do have one “weather event” this week and that will be strong east wind Tuesday.  The deep low offshore and high pressure east of the Cascades gives us at least 8 millibars easterly flow; lots of chilly east wind with rain that day.  And it may be somewhat widespread in the metro area.

That’s it for now…enjoy the mild weather this week.

Chief Meteorologist Mark Nelsen

 


Strong Wind Arriving

January 5, 2019

10pm Saturday…

Models have done a very good job showing the strong southerly wind surge arriving in the metro area between 10pm & Midnight or so.  Strong wind hit Salem in the past hour and now it’s arriving in Portland.  The easterly Gorge gradient has rapidly died down so ALL of us get that strong southerly direction the next 2 hours or so before dying down.

At 10pm here at the peak gusts so far, most notable for a few strange spots which we typically don’t see strong wind reports from

Hillsboro 37
McMinnville: 54
Yamhill:  53
Aurora: 48
Estacada-Springwater: 44
Salem: 54
Salem (Hwy 22 near State Penn):  62
Eugene: 43

I’m not on the air right now due to a death in my close family earlier today.  But Anne Campolongo will be doing a great job on FOX12; you can watch for the next hour.  Don’t worry, this weather geek stuff relaxes me and I enjoy it or I wouldn’t be posting.  Strange, but true!

Be careful as always if you use a generator/candles/heater while the power is out tonight.  I see there are already 11,000 PGE customers out of service right now.

Chief Meteorologist Mark Nelsen


Brief Wind Storm Tonight

January 5, 2019

9am Saturday…

It’s been a real quiet winter so far, and it appears to remain that way the next 10+ days.  But a system sliding up the coastline tonight stands a good chance at giving us the strongest gusts of winter so far…

HIGHLIGHTS FOR WESTERN VALLEYS INCLUDING PORTLAND METRO

  • Today is a quiet weather day, but with an increasing easterly wind blowing out of the Gorge.  Quite windy for the usual spots out there!
  • Sometime between 10pm and 1am a strong south/southwest wind suddenly arrives; it should happen quickly
  • Expect the strongest gusts of this season so far for many of us, 45-60 mph at official observing locations (airports).  I’m sure somewhere on Chehalem Mountain, in the West Hills, on Mt. Scott, or a freeway bridge, there will be a gust over 60-65 mph.
  • This isn’t “the big one”, and it won’t last more than 2 hours or so, but…
  • Strong enough to bring down trees, and knock out power to many areas
  • By sunrise it’ll be quiet again; if you go to bed early and don’t lose your power, you may not know anything happened!

FOR OTHER AREAS

Coastline: The same sequence of events, gusts 60-80 mph are likely out there.  A brief but powerful hit of wind during the same time period as here in the valleys

Gorge: Gusty easterly to calm suddenly late this evening, no significant effects east of Multnomah Falls

Oregon Cascades:  Strong wind during the night, but ski areas will be closed at the time

Central/Eastern Oregon:  Windy, but nothing too unusual.

 

What’s New This Morning

It’s very nice to see ALL models showing the same basic progression of a surface low pressure center coming up the coastline this evening/tonight, a 982-987 center tracking from off Cape Blanco around sunset to somewhere in northern Puget Sound sometime between 1am-4am.  Once again the WRF-GFS from UW along with NAM-MM5 are both most intense deepening the low at the same time it’s moving north.  They both show it strengthening all the way until it moves north of us; never good if you want to avoid a windstorm.  Slide show gives you the basic idea.

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Note the tight packing of isobars for 1-3 hours directly over NW Oregon and SW Washington.  They are also oriented west-east at the same time. This is the PERFECT position for maximum wind gusts in the majority of our viewing area through the I-5 corridor from Longview to Albany.  In fact it’s rare to see such a setup.  This has grabbed my attention along with the quick rise in pressure at the same time.  Big pressure rises = lots of air rushing north.  The pressure gradients are a big deal here too.  NAM-MM5, WRF, RGEM, 3KM WRF-NAM, ECMWF; they all give us at least 15 millibars pressure gradient EUG-OLM.    If this were a 970-975 mph low we’d be in major windstorm territory, but luckily it isn’t.  The overnight ECMWF responded with gusts 60+ in the valley

ecmwf_windgusts

and the 12z WRF thinks we’ll have gusts up around 60 as well; this is very strong for the Portland area with this model.  If we really do get widespread gusts 60+ in the metro area it would be the strongest storm since December 2006.  We’ve had a few events where 60+ hit smaller parts of town, but not like what is depicted on both pressure and wind gust maps from the WRF.

wgsfc.18.0000

At the same time I’ve also noticed a few models don’t have a tight closed low (12z GFS and RPM).  That held back my wind speed forecast a bit from these numbers; I must be getting older and more conservative.

One other factor to consider is convection; pretty good hints that we’ll get hefty showers and/or thunder showers with the passage of the strongest wind; that can mix the stronger wind overhead down to sea level nicely.

By the way, the strongest gust at PDX so far this winter is 46 mph, once from an east wind and once from the southwest.  Hillsboro airport has hit 42, and Salem 48.  We should beat these numbers tonight.

As my boss once said; even the most well-forecast weather events never turn out exactly like we expect.  We have the basic timing and intensity down well, in about 15 hours we’ll see what happens!

A side note:  I want to give a HUGE shout-out to all my peers at the Portland National Weather Service.  As far as I’m aware, they are all going into week #2 with no pay.  Yes, yes, I know there’s a good chance they will get paid when it’s over as in the past.  But that makes the situation even more sad and wasteful than it already is.  In the private sector how many of you would continue showing up for a job if the boss told you “no pay until further notice”?  I’d be looking for another job, wouldn’t you?  Kudos to them for sticking around, staying on the job, and helping to protect lives/property during these weather events.  Remember that next time you complain about “government workers”.

Chief Meteorologist Mark Nelsen

 


Wild West Coast Weekend; Possible Windstorm Saturday Evening In Valley

January 4, 2019

10:30am Friday…

I’ve mentioned numerous times this cool season has been a real dud for weather excitement, and we’re more than halfway through it.  Well now we are in early January and for the first time we have the possibility of a significant wind event or even an actual wind storm here in the western valleys of Oregon and southwest Washington.  It’s only a possibility for now, but I figure it’s my job to keep you updated!

 

What’s happening?

Models all show that two deep low pressure systems will move onto the West Coast about 24 hours apart.  Those weather forecast models have come together quite a bit this morning showing the first moving north up the Oregon/Washington coastline Saturday evening/night, then a 2nd through southern Oregon and northern California Sunday evening/night.  The first is the one we are most interested in because this could be a strong wind producer.  The second gives southern Oregon a big snowstorm and strong wind down into California but few effects in our viewing area.

Here’s a slideshow from the WRF-GFS model showing the general idea…4pm Saturday a deep low pressure area is off the southern Oregon coast, then it progresses/swings north as an elongated “dip” in the atmosphere.  By 10pm it’s up off the Washington coast.  Air rushes in to fill that “dip” and we get a strong southerly wind as the low passes by.  A “classic” wind storm setup.

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If this exact setup occurs, we’d have a brief but intense windstorm on the coastline AND in the Willamette Valley/Metro as pressure rises rapidly behind the low.  With a strong wind field overhead plus those isobars oriented directly west/east perpendicular to the valley, we would be set for a big wind event.  This is the type of setup that gives us widespread 50-65 mph gusts in the valley; we haven’t seen that for a few years.

Now it’s important to note this is the most “intense looking model”, others are a bit weaker, or have the low almost directly overhead (far less wind).  It’s still 30 hours away so we’ll see what changes with evening and Saturday AM model runs.

A good example is the morning Euro (ECMWF) model run.  It is significantly weaker with a weaker low pressure center, which is barely a center at all.  More of a wind surge coming up the valley at a later time.  It shows more like 30-45 mph gusts, what we’ve already seen this season and no big deal.

WHAT COULD CHANGE IN THE NEXT 24 HOURS?

  • If the low moves directly over the Portland Metro Area, all strong wind would be to the south = no wind storm
  • Models could decide low will be much weaker as the ECMWF does = we just get a regular breezy Saturday evening = no wind storm
  • Models hold the same course and we actually get a widespread strong southerly windstorm in the Willamette Valley, we haven’t seen that in a few years.

SHOULD I DO ANYTHING DIFFERENT BASED ON THIS OUTLOOK?

No, don’t cancel anything or alter your plans this weekend; that would be silly at this point.  Maybe have some candles/flashlights ready in case the power goes out.  Or if you live in a rural area make sure your generator is working.  That should always be the case in our November-February storm season anyway.  Other than that there’s nothing you can do to “prepare” for a wind storm.  It gets windy for a few hours and then it dies down.

SUMMARY

  1. Through 4pm Saturday nothing interesting happens, except for the usual gusty east wind developing through the Gorge and into east metro area
  2. Strong southerly wind is POSSIBLE around sunset and into the evening hours  Saturday throughout our viewing area (especially west of the Cascades) but by no means a guarantee at this point
  3. Get ready for power outages and downed trees if we do get strong wind

Stay Tuned!

 

Chief Meteorologist Mark Nelsen


Coldest Time of Year, But No Lowland Snow/Cold In Sight

January 2, 2019

6:30pm Wednesday…

We’re into early January now, which is the midpoint of our cold/stormy season west of the Cascades.  As mentioned numerous times, this has been a real dud of a “storm season”.

In an average year (rarely is any one year “average”), we are in the coldest time of year west of the Cascades  right now.  That’s late December and the first week of January.  Here in Portland the 30-year normal is 45 & 35 for a high/low temp.  That goes to 46/35 starting Sunday and 47/36 a week from Sunday.  Not exactly a big warm-up, but a sign that we SLOWLY begin to come out of the coldest part of the year the 2nd half of January.  Take a look at January snowfall in Portland the past 11 years.  4 of those years we saw measurable snow

January Snow PDX

So the biggest question I’m getting…Do we see snow/ice in the near/far future?   The short answer is NO

Looking at all the different models it’s quite clear that the mild/splitty pattern continues through the first half of this month.  In two days we have a weak system moving overhead while the southern portion moves well south into California.  Here’s the GFS upper level (500 millibar) map:

fri_4th

By next Monday the jet seems to get itself together briefly for a wetter/active storm system.  Could be some brief weather action early next week

mon_7th

But then by Thursday the 10th things are very splitty again

thu_10th

At mid-month, Tuesday the 15th, both GFS and GEM are trying to develop more significant ridging over the Pacific Northwest.

tue_15th

The ECMWF does not have that upper-level ridging at mid-month so we’ll see how that turns out.

The theme here is that relatively mild and occasionally wet weather will continue.   There is no sign of lowland snow/ice through mid-month in this weather pattern.

Snow Portland Preview

So if you didn’t put on snow tires I sure don’t see any reason to put them on now.  And keep in mind that during these weak El Nino winters February if often mild.  Not always, but often.

That’s it for now, just wanted to give you a quick update during this “coldest time of year”.

Chief Meteorologist Mark Nelsen


A Warm December ends With a Cold New Year’s Eve

December 30, 2018

5pm Sunday…

We had a nice cold front pass through the region Saturday evening, leaving us with scattered showers and sunbreaks today.    Tonight skies begin to clear out as we get into a cool northeast flow for a couple days.  This isn’t an “east wind comes blasting in with bitter cold temps” sort of setup.  It’s just back to normal temps or even a little below (especially at night) for most of us.  That’s something we haven’t seen much of the past 2-3 weeks.  Since early October we’ve been in a mild/warm weather pattern much of the time.  This December will likely end up in the top 10 warmest at PDX.  As of the 29th, it’s the warmest since 1979, but that will change with cooler temps this evening and Monday.

Month Climate Temps Calendar

We have caught up on rain, making it just about average for December.  Snowpack has been slowly improving the past week as well.  Now over 50% throughout Oregon with much of Eastern Oregon right at average.  Very nice! Considering I can hardly see movement on Hwy 26 @ Timberline Road on the ODOT camera at 5pm, I’m guessing that a LOT of you are enjoying the snow?

or_swepctnormal_update

One thing we’ve been missing?  Those of us in the east wind areas missed the cold nights in early December, meaning some parts of Portland central/east metro have barely seen a frost!  PDX has hit 32 four different times, and will likely do it either tomorrow morning or by midnight tomorrow night once again

Mark Warm Low Temps

That’s quite unusual, even for that relatively urbanized location at the airport.  All the rest of us in the western valleys have been down into at least the mid-upper 20s.

Mark Warm Low Temps2

You can see that most Decembers we get at least down into the mid-upper 20s at some point at PDX

December Coldest Night Each Year

 

We are 1/2 of the way through our “storm & cold” season and I think it’s fair to say it’s been a real dud so far.  It shouldn’t be a surprise in this El Nino winter; these are sometimes quite boring for the geeks like me.  Yes, I know it’s not officially an El Nino, but most likely it will be considered one once we look back on it.  It’s especially disappointing considering it’s our second consecutive cool season (so far) with not much exciting weather.  You may recall that last year was a real dud from November through mid-February, except for that Christmas ice/snow.

What’s ahead?

It’s very clear that we’re back into a ridgy/split-flow pattern for the next 7-10 days.  Little or no storminess, just occasional wet weather systems.  Temperatures will likely be milder than normal for at least the first week of January.  The 18z GFS shows 3 systems splitting as they move towards the coastline: this Friday, Wednesday the 9th, and Friday the 11th.

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The ECMWF model is a little more consolidated the next 10 days, but still “weak” looking.

SUMMARY

  • THERE IS NO INDICATION THAT WE’LL SEE ANY LOWLAND SNOW/ICE IN THE NEXT 10 DAYS
  • NEW YEARS EVE WILL BE CHILLY AND CLEAR AT MIDNIGHT; POSSIBLY A FEW SPOTS OF FOG DEVELOPING LATER
  • NEXT CHANCE FOR RAIN IS THURSDAY

Chief Meteorologist Mark Nelsen

 


Those 12 Days of Christmas? Looking Quiet Weather-Wise

December 26, 2018

7pm Wednesday…

Merry Christmas to all!  Hope you had a great holiday and enjoy this fun Christmas Week leading up to the New Year.

I’m confident the weather won’t be affecting your plans much.

Why?

Because after some briefly exciting weather mid-month things are back to “slow” once again which has been the story since early November.  Mild too.  This December is running 8th warmest of the past 75+ years at PDX.

Here’s what I see as we head through these 12 days of Christmas (through Friday the 4th):

  • No sign of arctic cold or low-elevation snow
  • No sign of freezing rain in the metro area
  • No big storms with high winds or flooding

We have just ONE organized warm/cold frontal system coming through Saturday through early Sunday.  Even that one isn’t very impressive, but will give us a nice shot of Saturday night rain and mountain snow.   There are hints another organized system could come through about a week from tomorrow too.

Note the ECMWF meteogram shows nothing interesting temp-wise (unusually warm OR cold) the next 15 days.  This is the average of all 51 ensemble members:

KPDX_2018122612_eps_min_max_15

Far more interesting from a meteorological standpoint is that NONE of those ensemble members show snow in Portland during the next two weeks.  The point here is that we seem to be in weak upper-level ridging and/or a splitty/weak jet stream for the next 10-15 days.  On any typical winter day I’ll see at least a few of those horizontal lines showing some snow at some point during the next two weeks.  That shows there is good agreement on an average to above-average temperature regime to start January.

KPDX_2018122612_eps24_snow_360

That said I don’t see a dry east wind setup to give us significant sunshine until next Monday; we’ll be seeing plenty of gray tomorrow through the weekend.

This IS turning out to be a typical weak/moderate El Nino cool season in our area…a bit drier and warmer than average.

Chief Meteorologist Mark Nelsen