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