A Little Bit of Mountain Snow, and Possible Excitement in the Extended?

Valid 05:00 pm PDT Thu, 03 Nov 2011 – 36hr Fcst – UW 4km 12z WRF-GFS 24-hour snowfall

The Northeast got walloped by snowfall this past weekend, but we will soon see our first pass-level snowfall event in the mountains! There will be no power outages to millions of people, there will be no record-breaking snowfalls, and there will definitely be no questions over the status of global warming with this system though. The snow will be confined to the mountains above 2,500 feet, and there won’t be too much of it. The National Weather Service office in Seattle issued this weather story graphic today:

Mt. Baker will be an exception, with some places on the mountain receiving over a foot. However, Mt. Baker is the snowiest place in the U.S., and it typically receives more snow than other areas. This storm won’t be anything to write home about, but it is significant because it will bring the first measurable snowfall of the season down to Snoqualmie Pass. It will be fun to look at the webcams… I’m very excited for ski season.

Valid 05:00 pm PDT Wed, 02 Nov 2011 – 12hr Fcst – UW 12km 12z WRF-GFS 3-hour precip

The models say we will start seeing rain here in Seattle around 5 P.M., but I think they are off on their timing. I’m going to push the timing up ahead two hours, so I think we will start seeing rain here at 3 P.M., and maybe even earlier than that. This system will be a quick mover and won’t generate too much rainfall… maybe a half-inch at most for spots in the lowlands. Also, there won’t be as much post-frontal shower activity as we usually see with fronts because most of the showers behind the front are dipping down to our south.

We will see another front on Saturday, but this front will be weaker than the one we will see today, and most of the energy will head south. 

Valid 05:00 pm PDT Sat, 05 Nov 2011 – 84hr Fcst – UW 12km 12z WRF-GFS 3-hour precip

In between these features, we will see cool, partly cloudy skies. Honestly, the weather will be pretty boring. However, some excitement may come our way next week.

I’ve been watching a feature on the models that has been fairly consistent in some ways and wildly different in others.  Basically, something fairly exciting could happen next week. We will probably see a strong front give us a good dose of rain in the lowlands, but we could see some pretty windy conditions as well. Here are some WRF-GFS maps in the extended.

Valid 01:00 am PST Tue, 08 Nov 2011 – 141hr Fcst – UW 36km 12z WRF-GFS 3-hour precip

 Valid 04:00 pm PST Tue, 08 Nov 2011 – 156hr Fcst – UW 36km 12z WRF-GFS 3-hour precip

Between these two frames, it is raining heavily over Western Washington. This looks like a moderate pineapple express event over our area. 

Now, let’s look at the Canadian model. These shots are from the 00z run last night.

This above shot is for Wednesday afternoon over us. Look at that strong wave offshore.

That wave comes to our south and gives areas south of us heavy precipitation and wind. If it were December or January, we could be talking about lowland snow, but it is a bit early for that.

The European model shows a solution similar to the GFS for Tuesday afternoon.

The bottom line here is we really don’t quite know what will happen next week… but I have a feeling it could be exciting! Stay tuned.

Charlie