Another Wet Week Ahead

5:55 p.m.

And the hits just keep on coming.

After our not-so-close brush with snow (it’s easy to get excited looking at models beforehand, but when push comes to shove, this is Seattle, and we live right next to Puget Sound and the Pacific Ocean and are protected from cold air by the Rockies AND Cascades. Cliff Mass actually has actually has an excellent post on our protection from cold air here), it’s time to get back to a warmer, milder, and, dare I say, wetter pattern. We actually had some brilliant sunshine over the past week, but alas, that is coming to an end. Let’s take a look at the current upper level flow, and how it is expected to develop over this week.

Valid 04:00 pm PST, Sun 02 Mar 2014:   http://www.atmos.washington.edu/~ovens/wxloop.cgi?mm5d1_x_500vor+///3

As you can see, the flow we have coming in is pretty zonal; that is, it is coming directly off the Pacific and is in a more-or-less straight line as opposed to being curvy with lots of ridges and troughs everywhere. When we get a pattern like this, we get storms, and if the jet stream has sufficient velocity, some of these storms can be quite strong. This was the pattern we were in for much of February when we were piling up snow in the mountains, and it looks like we will pile some more snow up there this week. However, snow levels will be higher, so Snoqualmie will likely alternate between periods of rain and snow.

Speaking of snow, it is snowing like no other up there. It’s 19 degrees at the summit with chains required on all vehicles except all-wheel drive. The picture above is at Hyak (Summit East) @ milepost 54 on I-90, which is two miles east of the crest. Too bad we didn’t see any snow like that down in Seattle.

Valid 01:00 am PST, Thu 06 Mar 2014 – 93hr Fcst:   www.atmos.washington.edu/~ovens/wxloop.cgi?mm5d1_x_500vor+2014030212///3

As we go forward through the week, a trough will approach our coast and affect us Thursday. See that slight ridge behind the trough? That’ll come in on Friday.

Valid 10:00 am PST, Fri 07 Mar 2014 – 126hr Fcst:   www.atmos.washington.edu/~ovens/wxloop.cgi?mm5d1_x_500vor+2014030212///3

This will be a very progressive pattern, meaning that storms will come through pretty quickly, and the ridges between storms will swing through the area instead of setting up shop and shunting the jet stream to the north. After this ridge sweeps through, we’ll be back in our ol’ trusty zonal flow for the foreseeable future.

Throughout the period, highs will be in the mid-50s. As I said before, the snow level will unfortunately be higher for this series of storms. In fact, levels are predicted to skyrocket to 6-7000 feet in the Central Cascades with a rather strong storm that is predicted to come on Wednesday. I’ll have more information on this guy in a post tomorrow. There is a possibility that the passes may be insulated from the warming at times due to cool air from eastern Washington flowing westward through them. Snow levels should be significantly lower – 3-4000 feet – in the North Cascades.

It may not seem like it, but spring is definitely in the air! I tend to get my allergies really early in the season, and I was definitely feeling them this past week. Hopefully the rain this week will make my days a little less miserable. 🙂

Charlie