The Big Dump of Snow

February 19, 2014

What a crazy 3 weeks in the Cascades, and it’s topped off by an extremely heavy snowfall this evening.  As of 10pm Timberline has seen 20″ of snow in the past 24 hours!  Mt. Hood Meadows has seen over 100″ of snow this month.  Snow depth is up to 118″ at Meadows and 133″ at Timberline.  That’s getting very close to normal at those elevations.

So what’s the big picture look like?  Take a look at the big jump in percentage of normal snowpack at two sites around Mt. Hood.  The first is the usual snow measuring site below Timberline.  The other is near Mt. Defiance west of Hood River at a lower elevation:

MarkSnowpackChange_2Sites

Not so bad eh?  And I see more through tomorrow, and then a bit more Monday & Tuesday before we dry out.

Friday through Sunday looks uneventful in our area as cooler air filters down from the north.  Temperatures will be below normal (52-53 highs are normal).  But then things get interesting Monday.  That’s because all models advertise a cold arctic high dropping down to our east with the cold air just missing us Sunday.  Then as low pressure gets closer to us Monday, strong offshore flow pulls cold air down into the eastern side of Washington and northern Oregon.  Models are forecasting 8-10 millibars easterly gradient through the Gorge on Monday.  Then moisture overruns that cold air.  Sound familiar?  Yes, similar to what we had the first week of February but the atmosphere is 10-15 degrees warmer and the cold air doesn’t spill south into the Willamette Valley.  Tonight’s 00z run of the WRF-GFS is about the 4th in a row to show the same thing, and the ECMWF, with its lower resolution looks about the same.  They all have precipitation in here Monday.  Below is what the WRF-GFS is forecasting for snow.  This HAS backed off substantially the last few runs; at one point it showed many inches right over Portland :

or_snow72.144.0000

As a result, I think there is a decent chance a snow/ice event is headed for at least the central/eastern Columbia River Gorge.  Could be freezing rain at the west end of the Gorge too.  OR, models may be pulling too much cold air down into the Columbia Basin so it’ll only be marginal even in the Gorge.  Luckily it’s still 5 days away.

Regardless, all models show precipitation and a strong east wind Monday and Tuesday…a chilly last few days of February!

Chief Meteorologist Mark Nelsen