A strong Puget Sound Convergence Zone formed Tuesday morning and brought hail, snow and lightning to the greater Everett and southern Snohomish County areas. So far snow accumulations were light, but Port Townsend did reports 1/2" to 3/4" accumulation of hail.
A Winter Weather Advisory is now in effect for the greater Everett area as well as Snohomish and Island Counties and the Port Townsend area for as much as 1-3" of snow inside the zone (highest amounts to the east) and potential hail through the afternoon as the zone reforms and wanes.
Trooper Keith Leary with the State Patrol says the 88th Street Overpass over I-5 was compact snow and ice with vehicles getting stuck. Fellow troopers have responded to a handful of spin-outs, non-injury collisions in the area.
The zone was likely to continue to hang out around this area and perhaps drift a little further south into Seattle area later today, keeping a chance of rain, snow, hail and lightning through the day. He also reported SR-2 near mile post 35 had several cars stuck and sliding as of late Tuesday morning.
Overnight, snow was reported in parts of Seattle, Renton, Bellevue and Mountlake Terrace, but didn't accumulate to much. Up in the foothills, anywhere from 1-2" fell in Snoqualmie and North Bend.
The snow caused a few school districts to delay start of classes and declare some snow routes, but otherwise there were few issues.
Snow showers will continue in the zone area through Tuesday evening, but outside the zone we'll see isolated rain or snow showers with little to no accumulations.
Potentially major snow event on Wednesday
But this was just the beginning, as some of the snowiest -- and coldest -- weather so far this winter is heading to your backyard. Many are looking at the potential combination of heavy snow and blistering wind as soon as late tonight.
A Winter Storm Watch remains in effect for Wednesday through Thursday morning for the entire Puget Sound lowlands, including Seattle, Tacoma, Olympia, Everett, Bellingham, and the Eastside. The watch also includes the Strait of Juan de Fuca, the islands, and the Washington coast.
Latest computer models suggest snow totals could reach 4-6" in spots during the day Wednesday -- even in Seattle -- with some spots perhaps getting more while others a little less. But there is also growing potential for an event similar to what occurred in late November when arctic air moved in behind the snow and instantly turned roads into skating rinks.
I'll set this up by period:
Models indicate the first batch of moisture from an approaching low pressure trough will move into the central and south coast and southwestern Washington around midnight, then push north into the Puget Sound area toward dawn. This is expected to bring a slushy snow similar to what was occurring in Everett with temperatures at or slightly above freezing. However some areas could see 1-3" of this wet snow and it'll be a close call whether it gets here before, during or after the Wednesday morning commute.
Wednesday morning to midday
As we go through Wednesday morning into midday, snow showers will continue to increase across the area. Most of these showers will be clumps that can bring an intense snow that quickly accumulates to a few inches and bring low visibility as it does so, meaning they have the potential to really catch people off-guard . However, areas that miss the showers will see less to perhaps little-to-no snow. Temperatures during the morning and midday hours will likely be in the mid-upper 30s, so we're talking still a slushy snow, but by midday some areas could be up to 1-4".
Wednesday afternoon to evening
As that low moves to our south, this will unlock the cold, arctic air bundled in British Columbia. As that arctic air moves south, it will collide with the moisture moving from the low to northeast and create a wide area of convergence -- perhaps a really large convergence zone. This boundary will likely create a heavy band of snow that will gradually slip south during the afternoon, eventually through the Seattle Metro area.
What's worse is that behind this band of snow, temperatures are expected to drop below freezing. That would set up a similar scenario to what occurred in our late November snow event, only over a wider area with perhaps greater snow amounts.
If that pans out, it would have a major impact on the Wednesday evening commute. Earlier timing had this event more reserved for Wednesday night but newer models are bringing it in faster.
Up north around Whatcom County and the San Juan Islands, expect strong northwest winds out of the Fraser River Valley gusting as high as 50-55 mph. This will bring
Snow will taper off from the north as the night progresses for most, and temperatures will gradually fall into the upper 20s to near 30. However, snow looks like it's going to stubbornly hang around from Seattle south through the night.
We will continue the drying trend from the north, but still some snow possible Seattle south, slowly ending as the day goes on. This could put down another 1-3".
In all, we are going for storm totals around 4-6" as a general rule across the lowlands. Some areas that might see more are the northern Olympic Peninsula, the Cascade foothills, and anywhere where a band of showers rolls through and/or stalls. As of Tuesday morning forecasting models also indicate Snohomish County into North Seattle and southern Skagit County will have a good chance at 4-6" accumulations.
Icy conditions develop in storm's wake
As the snow ends Thursday, we go into the ice box.
Models indicate we dry out as more arctic air pools into the region, and return to a cold and sunny pattern for the end of the week. Highs on Thursday, Friday and Saturday will only be in the 30s with hard freezes overnight. Lows in Seattle will drop to the low-mid 20s with teens likely in the outlying areas. Long range models indicate perhaps more chances for snow late in the weekend and into early next week.
* Snow at times Tuesday in the Convergence Zone. Winter Weather Advisory remains in effect until 4 p.m. * Rain/snow showers continue to roam in Tuesday night. Could see 1-3" of slushy accumulations late Tuesday night from Seattle area south and west to coast. * Snow showers increase Wednesday in heavy snow bands. Slushy 1-4" to start. Temps still in mid 30s. Morning commute could be affected. * Heavy band of snow sets up in North Sound on Wednesday, slowly moving south through the afternoon and night. * Wednesday evening commute could feature heavy snow and/or freezing temperatures. * Snow on northern Olympic Peninsula could be greater than 6" Wednesday. * Strong winds blow out of Fraser River Valley gusting to 50-60 mph in Whatcom and San Juan counties. * Freezing spray an issue to mariners around San Juans and waters off Whatcom County. * Temperatures to drop below freezing late Wednesday into Wednesday night * Very cold temperatures expected late Thursday night into Saturday. * Heavy snow continues in mountain passes.
Heavy snow in mountains, too
A Winter Storm Warning continues for the Cascades, which will get moderate to heavy snow through Thursday. Forecasted snow totals are for 18-24" by Wednesday morning but there is plenty more behind it through Thursday.
--- Get Latest Updates on Twitter & Facebook!
The KOMO Weather Staff will be providing frequent updates through the week on Facebook and Twitter: