Friday, December 18, 2015

Snowy weather ahead

After a very wet and mild start to the month of December, the pattern has changed with storms now coming at the region from the west and northwest.  This will bring several opportunities for snow and the chances of a White Christmas are looking good for most of the Inland NW.  Let's dig deeper into where we are now and what lies ahead.

The first colder storm that tracked through Thursday and Friday has blanketed the region with snow.  Here's an analysis of snow on the ground.

This is just the beginning of the snow.  A storm Saturday night and Sunday will bring light to moderate accumulations.  Here is our forecast as of Friday afternoon for Saturday night and Sunday.

It looks like snow will reach the Cascades Saturday night and then the remainder of Eastern Washington and North Idaho on Sunday.

A stronger storm is on tap for Monday.  Here is what one of the forecast models is showing.

Dec 18th/18z GFS model run valid 10 am Monday showing 500mb height and 700-500mb Relative Humidity
Note the large area of green over the region indicating lots of moisture.  Here is our forecast as of Friday afternoon for snow amounts Monday into Monday night.

This one could bring moderate to heavy snow amounts for most of the area.  Exception could be around Moses Lake, and Lewiston areas where milder air coming up from the south may limit accumulations as rain may mix in with the snow.

The snow that falls is expected to hang around a while as a cooler northwest flow sets up for the middle to end of next week.   Models are showing an upper ridge building in the Gulf of Alaska with a cool trough over the region.  This could bring cool weather and snow showers to the region especially in the mountains.  Here is what one of the model forecasts look like for Christmas Eve.

Dec 18th/18z GFS model run valid 10 am Christmas Eve showing 500mb height and 700-500mb Relative Humidity
And the latest CPC outlooks agree with this cooler pattern.  Take a look at the temperature outlook below valid Dec 24th-28th.

So, after a mild and wet start to December, it looks like the month will finish colder and snowy with a White Christmas for most.


  1. Awesome!...not quite the snowy deluge I was hoping for..but I'll take it under the circumstances (El Nino)...

  2. Interesting, as the CPC has us pegged for above normal temps and below normal precipitation as of Dec. 17th. I know those CPC forecasts are general, yet, they seem a off.