Spring's already had wind, rain, and now some snow?

Spring's already had wind, rain, and now some snow?
Photo taken at the Clearview Shopping Center on Highway 9 near Cathcart. (Photo courtesy: Jeff Faucett (@jdfaucett))
SEATTLE -- With strong winds, heavy rain, and even some very large hail, spring has managed to do more in 12 hours around here than winter seemed to manage in its entire three-month reign.

And now, it's going for its crowning achievement: Perhaps even adding in some lowland snow.

Colder air is rushing in behind Wednesday's storm and by Thursday morning, it'll be cold enough that some wet snow could be falling in a few spots around the region -- even at sea-level Seattle, though the odds of it sticking there are fairly low.

Snow levels will drop to about 500 feet by Thursday morning, and perhaps even temporarily dropping lower as scattered heavy showers move through. In addition, conditions are very favorable for Puget Sound Convergence Zone development -- which is really where the snow chances come in.

If a convergence zone is intense enough, it can bring snow levels down to the surface and leave a quick dusting to a few inches of snow accumulation. In between the showers though, temperatures will warm back into the 40s so it'll rapidly melt.

The forecasted wind patterns suggest the convergence zone will primarily be in its usual spots of Snohomish County into perhaps northern King County late Wednesday night through much of Thursday, but then a wind shift late Thursday could push the zone further south into central King County (Seattle-Bellevue) and maybe even as far south as Tacoma late Thursday into Thursday night -- even into early Friday morning.

Convergence zones are very fickle and can go through multiple periods of development and weakening so they are notoriously difficult to forecast and keeping an eye on the radar Thursday would be a good suggestion. I'll be giving frequent updates through the day on Twitter @ScottSKOMO.

But let's put it this way: The best chances for a little accumulated snow (maybe 1-2" in spots) are in the Convergence Zone areas of southern Snohomish County above 500 feet (Alderwood, Lynnwood, Mukilteo, S. Everett, Mountlake Terrace, Brier, Mill Creek, Bothell, Edmonds above the bowl to name a few.) and also in the Cascade foothills of Snohomish and King County (Issaquah, North Bend, Snoqualmie) where you have enough elevation that random snow showers might be enough to briefly accumulate.

Outside those areas, showers could be rain/snow mix or wet snow, but little to no accumulations are expected -- especially near Puget Sound -- and what ever falls will quickly melt when the shower stops. Don't forget the ground temperatures are quite warm as it's been well above freezing for days so accumulations would mainly occur only when the rate of snow overwhelms the rate of melting and primarily on grassy surfaces.

In other words, no arctic outbreak here, just enough snow to perhaps briefly change things white for a short time.

To summarize the timing, snow levels should be ready around 500 feet by Thursday morning and thus these wet snow showers are possible through the day and Thursday night, even into early Friday morning. Temperatures will be in the low-mid 40s when it's not raining/snowing, but will drop to the mid 30s during snow showers. (Found out why that happens in our Seattle Snow Scenario FAQ.)

We begin to run out of moisture on Friday with clearing skies but temperatures will remain unseasonably cold with lows Friday morning in the low-mid 30s and highs in the mid 40s. Temperatures Friday night could drop into the upper 20s in the outlying areas to the low-mid 30s in the city. We'll slowly moderate through the weekend.