Announcement
The Northwest Weather Workshop, the big annual weather gathering in the Northwest, will take place on March 3-4, 2017 in Seattle (NOAA Sand Point Facility). Everyone is welcome. For more information and to register, go to https://www.atmos.washington.edu/pnww/
___________________
One more band of snow will be passing over western Washington during the next few hours, but for most of you, the majority of the snow of this event has already fallen. Amounts so far range from 1.5 inches near the water in north Seattle to 15 inches on the higher hills of the eastern suburbs. Many of the schools are closed (including the UW!) and there are extensive power outages from branches laden with wet/heavy snow falling on power lines. As shown by the outage maps, about 6000 customers have lost power in Seattle, roughly 80,000 lost power in the PSE system, and several thousand in the Snohomish PUD system.
Snoqualmie Pass is closed and the cams don't suggest an early opening.
Snow amounts varied hugely. I had the misfortune of living in one of the least snowy locations (north Seattle with 1.75 inches). On the other hand, on the hills behind Bellevue, one location had 14 inches (see picture from Peter Benda).
Some reports were collected by the National Weather Service (see below). A number of locations in the Sound Sound and eastern suburbs got roughly 6 inches of snow.
That easterly flow, low elevation, and water influence resulted in less snow in parts of Seattle. Bummer.
The latest UW WRF snow forecast for the 24h ending 4 AM Tuesday shows modest snow (2-4 inches) over the mountains, NW Washington, and SW Washington, but Puget Sound get much less. Why?
Answer: we will be "snowshadowed" by the Olympics as westerly flow develops aloft (see forecast map at 850 hPa--around 5000 ft-- for 1 PM. Winds are parallel to the lines.
Was this forecast a success? Was the uncertainty information useful? We will get feedback during the next several days.
Finally, let us note that there has been massive snows in the Northwest mountains (several feet of new snow the past several days), which is great for skiers and wonderful for water resources next summer. And California is now being hit by massive amounts of precipitation as well, further reducing any fears of drought or water shortages there later this year.
The Northwest Weather Workshop, the big annual weather gathering in the Northwest, will take place on March 3-4, 2017 in Seattle (NOAA Sand Point Facility). Everyone is welcome. For more information and to register, go to https://www.atmos.washington.edu/pnww/
___________________
One more band of snow will be passing over western Washington during the next few hours, but for most of you, the majority of the snow of this event has already fallen. Amounts so far range from 1.5 inches near the water in north Seattle to 15 inches on the higher hills of the eastern suburbs. Many of the schools are closed (including the UW!) and there are extensive power outages from branches laden with wet/heavy snow falling on power lines. As shown by the outage maps, about 6000 customers have lost power in Seattle, roughly 80,000 lost power in the PSE system, and several thousand in the Snohomish PUD system.
Snoqualmie Pass is closed and the cams don't suggest an early opening.
Snow amounts varied hugely. I had the misfortune of living in one of the least snowy locations (north Seattle with 1.75 inches). On the other hand, on the hills behind Bellevue, one location had 14 inches (see picture from Peter Benda).
Some reports were collected by the National Weather Service (see below). A number of locations in the Sound Sound and eastern suburbs got roughly 6 inches of snow.
The snowfall yesterday heavily controlled by temperature, since the air temperatures were close to being marginal for snow. That was why the snow was so wet in many areas, resulting in power loss.
Being away from the water helped. Being higher helped. And precipitation intensity was critical. Heavy precipitation results in cooling by melting, which can drop the freezing/snow level to the surface. Another factor last night was easterly flow that developed west of the central WA Cascades last night that warmed the temperatures a few degrees and increased the temperatures a bit (see time-height cross section of temperature and winds at Seattle to see this).
That easterly flow, low elevation, and water influence resulted in less snow in parts of Seattle. Bummer.
Today, temperatures aloft are cold enough to snow...the issue is moisture. Recent radar and satellite imagery(8 AM) show a final band of precipitation coming off the Pacific (see figures)
The latest UW WRF snow forecast for the 24h ending 4 AM Tuesday shows modest snow (2-4 inches) over the mountains, NW Washington, and SW Washington, but Puget Sound get much less. Why?
Was this forecast a success? Was the uncertainty information useful? We will get feedback during the next several days.
Finally, let us note that there has been massive snows in the Northwest mountains (several feet of new snow the past several days), which is great for skiers and wonderful for water resources next summer. And California is now being hit by massive amounts of precipitation as well, further reducing any fears of drought or water shortages there later this year.
Public Information Statement
National Weather Service Seattle WA
736 AM PST Mon Feb 6 2017
...Snowfall Reports...
Location Amount Time/Date
...Washington...
...Clallam County...
6 E Joyce 1.0 in 0925 PM 02/05
...Grays Harbor County...
2 SSW Montesano 3.8 in 0554 AM 02/06
...Jefferson County...
S Brinnon 6.0 in 0730 AM 02/06
...King County...
Snoqualmie Ridge 12.0 in 0530 AM 02/06
4 WNW Enumclaw 11.0 in 0554 AM 02/06
S Bellevue 9.5 in 0700 AM 02/06
Renton 8.0 in 0554 AM 02/06
Newcastle 8.0 in 0725 AM 02/06
Kent E Hill 7.5 in 0700 AM 02/06
1 N Palmer 7.0 in 0603 AM 02/06
Highland Park 6.0 in 0730 AM 02/06
2 S Renton 6.0 in 0603 AM 02/06
4 WNW Enumclaw 6.0 in 0925 PM 02/05
Auburn/Federal Way 6.0 in 0645 AM 02/06
West Seattle Seaview 5.0 in 0700 AM 02/06
3 ESE Kent 4.5 in 0554 AM 02/06
Sunrise Heights 4.3 in 0530 AM 02/06
Mercer Island 4.0 in 0700 AM 02/06
SeaTac Airport 3.7 in 0453 AM 02/06
Magnolia - Seattle 3.5 in 0620 AM 02/06
Upper Fremont 2.0 in 0706 AM 02/06
Greenwood 2.0 in 0720 AM 02/06
Ballard 1.8 in 0700 AM 02/06
...Kitsap County...
Port Orchard 5.5 in 0530 AM 02/06
Bremerton 3.0 in 0620 AM 02/06
Seabeck 2.6 in 0650 AM 02/06
...Lewis County...
1 S Pe Ell 9.0 in 0652 AM 02/06
3 E Chehalis 7.0 in 0603 AM 02/06
4 NE Toledo 4.5 in 0603 AM 02/06
1 NNW Chehalis 3.0 in 0925 PM 02/05
...Pierce County...
Graham 14.0 in 0530 AM 02/06
1 S South Hill 14.0 in 0603 AM 02/06
Bonney Lake 13.0 in 0700 AM 02/06
5 NNW Eatonville 12.0 in 0925 PM 02/05
Frederickson 9.0 in 0650 AM 02/06
1 WNW Sumner 8.1 in 0925 PM 02/05
3 WNW Tacoma 7.0 in 0603 AM 02/06
Milton 6.0 in 0730 AM 02/06
1 WNW Ruston 5.0 in 0652 AM 02/06
1 S South Hill 4.5 in 0925 PM 02/05
2 S Ruston 4.5 in 0925 PM 02/05
2 S Graham 4.2 in 0925 PM 02/05
Ft. Lewis 3.0 in 0958 PM 02/05
...Snohomish County...
Duvall 7.5 in 0615 AM 02/06
4 NNW Sultan 4.0 in 0554 AM 02/06
Mill Creek 4.0 in 0625 AM 02/06
Tulalip 3.0 in 0730 AM 02/06
North Bothell/S Mill Creek 2.9 in 0530 AM 02/06
3 S Lake Stevens 2.2 in 0711 AM 02/06
1 SSW Esperance 2.0 in 0603 AM 02/06
...Skagit County...
Lake Cavanaugh 7.0 in 0704 AM 02/06
...Thurston County...
4 WSW Rainier 7.5 in 0554 AM 02/06
1 SSE Tumwater 3.0 in 0925 PM 02/05
2 SSW Yelm 3.0 in 0925 PM 02/05
...Whatcom County...
Mount Baker 5.5 in 0600 AM 02/06
4 WNW Ferndale 3.0 in 0603 AM 02/06
Post a Comment