Worst East Metro Ice Storm in 20 Years, But The Melt Is On!

December 10, 2016

As of 11am Saturday all metro area temps are above freezing, including the extreme western Gorge, west of Bridal Veil.  At my home it’s jumped above freezing as the southerly breezes arrive.  There have been widespread reports of 1″ or more ice across the east side of the metro area, with 2″+ in Corbett.  We haven’t seen ice accumulations like this since the disastrous 1996 storms in late December that year.  (10pm edit:  I wasn’t very specific.  This is the worst we’ve seen east of I-205 since the 1996 storm.  I’m totally aware that January 1998 and January 2004 saw extensive and damaging icing south/central/west metro that was worse than the past few days…by far.  In those events the eastern metro area that was hammered the past 24 hours saw far more snow and thinner ice accumulations, they were deeper into the cold air)

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Warming will continue the rest of the day and temperatures should jump into the 40s.  Be safe out there with ice falling all over the east side of the metro area!

Earlier today there were 25,000 of you out of power in PGE’s territory.  I haven’t seen that with ice in a long time.  All because the temperature was 30-32 instead of 33-35!

By the way, I did make it home last night, but ended up walking/running the last mile.  There were 3 whole trees down on my road and of course lots of pieces of ice crashing down.  Quite a surreal experience at 1am to be walking down an icy road with big bangs/thuds/crashes in the woods.  That phone light was only pointed up…but I have to say I felt more awake at that time than any other part of this week!

Chief Meteorologist Mark Nelsen

 


Cold Air Stuck in Gorge: Ice & Snow Continue Tonight

December 9, 2016

4pm Friday…

Well, in the past 24 hours here in Portland the temperature has warmed…wait for it…3 degrees.  But it’s worse.  I see it’s only risen 1-2 degrees at Troutdale, which is the location where the freezing cold air coming out of the Gorge enters the metro area.  But I know better and shouldn’t have fallen for the “quick warming” again!

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After countless events like this, I should have realized (again) that unless models forecast a significant southerly wind push up the valley (like they have been showing for days for Saturday), or a decent westerly wind in the Gorge, temps won’t warm up quickly at all.  As a result we are still in the same low-level air mass we were in yesterday at 4pm, and it has modified (warmed) by just a few degrees.  You can see how thin the cold air is overhead.  Check out the Troutdale profiler (in place for a Gorge wind study through this winter only):

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The left side is the most recent data, and time is in UTC.  23 is 3pm our time.  See the warmer layer above?  It’s less than 1,500′ above us.  So basically just above the top of the West Hills and Mt. Scott it’s in the 40s right now!

This situation will continue through tonight as well with no obvious warming until a gusty southerly wind picks up midday Saturday.

TONIGHT:  East of I-205 through the western end of the Gorge (and on the hilltops) temperatures remain at or below freezing and ice accumulation will continue.  That’s especially true on objects vs. roads.  I don’t think any metro roads are WORSE than they were this morning, but the increasing load of ice is going to be taking more of a toll as we go through the evening and overnight hours.  So the NWS is continuing the Freezing Rain Advisory for these areas and the Ice Storm Warning continues in the western Gorge.

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I saw one inch of ice in Corbett at 1-2pm when I headed into work:

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That’s a 6×6 or 8×8 sign post and of course because of the wind the ice is only on the upwind side.  By the time temperatures warm above freezing Saturday morning/midday, there could easily be 1.5″ to 2″ of ice accumulation, one of the biggest ice events we’ve seen out there since the disastrous December 1996 back to back ice storms.

Farther east, in the central/eastern Gorge (Bonneville to The Dalles) snow is continuing to fall so the Winter Storm Warning continues there through the night.  A total of 18″ is possible in spots:

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Although we’ll see quite a warm southerly wind in the valley tomorrow (and into parts of the western Gorge), that’s unlikely to translate into a big push of warming west wind farther east.  There won’t be a dramatic warming in the central/eastern Gorge tomorrow and temperatures will only rise a few degrees above freezing.  The kids can enjoy the snow for another day.

Sunday the slow thaw will continue with a better chance of a good westerly push of wind.  Regardless, temps should rise to around 40 degrees.

Chief Meteorologist Mark Nelsen


11pm: Major Gorge Snow & Ice Storm Developing

December 8, 2016

After checking all the evening maps and models one thing sure stuck out.  The cold air in the Gorge isn’t going anywhere until Saturday when a westerly wind should push it out.  My previous thinking and forecasts were based on this being a somewhat marginal event temperature-wise.  The problem is that the thick snow cover through the entire Columbia Basin is going to keep the “freezer going” through the day tomorrow.  At the same time we have a somewhat rare situation where overhead freezing levels are pretty low to start with…around 3,000′ tomorrow.

So precipitation will remain as snow in the central/eastern Gorge through tomorrow evening.  That’s a lot of precip still to go!  Most likely another 8-12″ from Cascade Locks to Hood River and 5-8″ at The Dalles.  That’s quite a snow storm when added to the ~8″ that has already fallen.

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Then there is another issue I didn’t anticipate related to that colder than expected air.  The east wind will back off, but still deliver a thinner layer of cold air into the WESTERN Gorge.  Looks like a solid .50 to 1.00″ of rain coming to that area.  That’s a LOT of heavy glazing on trees and powerlines.  This might be a bit overdone, but you get the idea on the ice accumulation forecast from our RPM model:

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Stay safe if you live in the Gorge!

Chief Meteorologist Mark Nelsen


4pm: A Good Forecast For Most

December 8, 2016

We’re in continuous coverage here at FOX12 at this hour (through 7pm at least), so just a brief note.  We’ve converted to mainly freezing rain in the metro area right on schedule.

Forecast was excellent for today, I’m in a pretty good mood after navigating two very tough snow forecasts this week (that includes the snow showers Monday)…It was mainly dry the first part of the day, then at noon everyone in the metro area had at least a trace as a line of snow squalls moved through.  I don’t see anyone that got more than 2″ either.  So a Trace to 2″ was just about right.  Models overdid the moisture a bit and definitely were too zealous converting the moisture to snow accumulation.  I was a bit concerned after Monday that it could happen again.  Part luck and part experience with that success.  One miss was the higher snowfall forecast from Hillsboro to Forest Grove.  That didn’t happen.  Those western areas converted to freezing rain just as fast as as the rest of the metro too.

What happens now?  Moisture supply somewhat runs out this evening.  We’ll go just to very light showers overnight…of course as mainly freezing rain.  Hilltop areas that are in the 20s and the eastern metro will stay totally frozen.  Roads shouldn’t get any worse in the other lower elevation areas

AM COMMUTE:  Still totally frozen in the hills and east of I-205 towards the Gorge.  A mix of wet and slushy/icy roads elsewhere.  Then we all thaw as the day wears on, even in hills and at Troutdale.

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Chief Meteorologist Mark Nelsen


Conditions Thread: Snow Totals & Location

December 8, 2016

Post your snow totals, temp and location here! If you’re seeing freezing rain or regular rain… let us know.


9:30am: Flurries Arriving

December 8, 2016

Good Morning!

Looks like the first flurries are arriving in the metro area with more significant precipitation (snow and freezing rain) having made it to the Salem and McMinnville areas in the past hour.

Everything is still on track forecast-wise.  The precipitation (all snow in metro area) picks up the next few hours and we should see a good burst of snow midday and afternoon.  The morning models still look almost exactly the same with that burst of heavier stuff during the afternoon.

Temperatures are exactly where we have been expecting them to be…most lowland locations are a few notches above freezing.  When the precipitation really kicks in those temps generally drop back to freezing, or, closer to the Gorge and in the hills down into the upper 20s due to evaporative cooling.  That happens when moisture falls into a very dry air mass.  It takes heat to evaporate so the temperature has to fall.

We’ll stick with our forecast TRACE-2″ in the middle of the metro area and 2-4″ far west metro, and far SW areas (Carlton/McMinnville) etc…, and maybe near the Gorge too.  All other points on the previous posts are still valid and I haven’t changed my thinking/forecast

Now it’s just a wait and see game for the weather folks…and you too.

This guy is waiting as well…

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Joseph Chung from a local weather group got this for his birthday yesterday.  Is he hoping for 5″???  We’ll see about that.

Chief Meteorologist Mark Nelsen


Winter Storm Warnings Issued

December 7, 2016

4pm…

I haven’t changed my thinking for this evening, but made the TV graphics to support the forecast from the previous post.  Midday models looked the same:

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