NORTH BEND, Wash. -- Travel across Snoqualmie Pass went from difficult to impossible Thursday as heavy snow forced the closure of I-90 for several hours Thursday.

The WSDOT says heavy snow caused several spinouts and crashes, prompting the freeway's closure between milepost 33 in North Bend and milepost 71 near Easton. Eastbound lanes reopened at 1:30 p.m. and westbound lanes reopened just after 3 p.m.

A Winter Storm Warning remained in effect for the Cascades through 6 p.m. for as much as 6-12 inches of new snow by late evening.

The lower Eastside hills had troubles too, as snow atop Tiger Mountain was enough to cause multiple spinouts along Highway 18. The State Patrol ended up closing the highway late Thursday morning between I-90 and Issaquah-Hobart Road, before reopening just after 1:30 p.m.

Meanwhile, in another example of just how variable the weather can be around here, not too far away in Gig Harbor, a spotter reported it was nearly 50 degrees and blazing sunshine late Thursday morning.

Some cooler air moved in behind a cold front early Thursday morning, dropping snow levels to about 400-500 feet. A Puget Sound Convergence Zone then formed and drifted south out of Snohomish County early Thursday morning and settled into east-central King County.

The Zone brought some accumulating snow to places like North Bend, Snoqualmie Ridge, Tiger Mountain, and Redmond's Union Hill. Most reports were about Trace-2" but a spotter just outside North Bend said they measured 4.1" of snow at noon.

Accumulating snow was not a threat for any other parts of the region.

We Play The Snow Game Again This Weekend

Our next weather challenge comes in over the weekend, as another cold system moves in on Saturday. This one is also from the northwest and has a chilly heritage from the Gulf of Alaska and in fact, looks like it'll usher in an unseasonably cold pattern through the middle of next week.

Saturday will start with rain developing - maybe snow again on the highest hilltops like Tiger and Cougar Mountain, and then rain will taper off to showers in the afternoon. This is when the cold air will begin to roll in and snow levels will drop to around 500 feet.

Thus, from a period of Saturday evening through Sunday morning, we have the general chance for snow or rain/snow mix showers, with light accumulating snow possible above 300-500 feet, but likely a rain/snow mix below, meaning most of the city of Seattle will likely stay bare, save for the hilltops.

There's two wrinkles here. First, a Convergence Zone is also possible Saturday evening into Saturday night, and that will increase the chance of lowland snow to the Northgate to Everett corridor if it forms. This could put down anywhere from a dusting to maybe 2-4" if it really rages. We'll also have to watch if it slides south -- much like today's did -- so King County should at least be on guard for a Convergence Zone snow, but better chances are north King and Snohomish County.

Another area to note is Whatcom/Skagit and San Juan Counties (hereto referred to as the Fraser River Outflow) which will begin a multiple-day event of experiencing some chilly air filtering out of the Fraser River Valley. This wind doesn't look too strong to push the cold air across the region, but locally up there, it'll keep things considerably cooler than the rest of us. Here, any moisture from Saturday evening on will probably be snow, but still, we're not working with a lot of moisture up here to make for major accumulations.

And again, for everyone else, it's random hit-and-miss snow or rain or mix showers, with spotty accumulations under 2".

Temperatures Saturday will be in the low 40s early, dropping into the 30s late. Saturday night's lows will be around freezing, and then Sunday's high temperatures will be near 40, except for the Fraser River Outflow areas, which will be in the 30s.

Monday looks dry but continued cool, with highs in the low-mid 40s generally, but mid 30s around Bellingham, and lows Monday night near freezing in the city -- perhaps upper 20s in the outlying areas and low-mid 20s in the Fraser Valley outflow area.

Long range forecasts now show just a few isolated showers Tuesday through Thursday, with continued cool temperatures, but moderating just a bit to the mid 40s. Bellingham will slowly lose the Fraser wind and will moderate as well and highs there will slowly climb into the low 40s.

Our next chance of real rain is now Friday. I suppose depending on how Bellingham scours out, it could briefly begin as snow there, but it won't stay that way for long, and the rest of the region all rain and upper 40s/low 50s for highs.

One thing is for sure -- the mountains will continue to get a healthy dose of snow.