Sent in by anonymous viewer in Ferndale, Jan. 26, 2008.

SEATTLE - Grab your popcorn, a favorite warm beverage, and a comfortable blanket, and sit back and watch as Mother Nature puts on an improv show featuring such players as rain, snow, freezing rain, dry air, humid air, and wind, likely making the whole thing up as she goes along.

If she were to take suggestions from the audience, "snow" would be far and away the largest popular vote, judging by our e-mail. But it appears at least in the first act, rain has won the electoral college.

We have a very complex weather pattern in play this weekend, which featured a weather system sliding down from the north, meeting up with a weather system moving up from the south.

Temperatures have been right on the edge of rain or snow today, but mostly just a few degrees warm enough for rain. Some colder air is moving in Saturday night as advertised, but we're now running out of moisture to work with.

A SNOW ADVISORY remains in effect for the East Puget Sound foothills through 4 a.m. Sunday for as much as 1-3" of snow overnight. That's for areas like North Bend, Snoqualmie, Issaquah Plateau and the like. But they appear to be one of the few snow lottery winners.

The Snow Advisory was canceled for the Hood Canal, north coast, and I-5 corridor from Snohomish County north to the border. That's not to say it won't still snow overnight, just accumulations are expected to be fairly light as we run out of moisture.

The Main Forecast

Saturday Night: A Few Snow Showers In Spots The cold front from the north was passing through the Puget Sound area Saturday evening. Unfortunately for snow fans, the front brought enough warm, south winds ahead of it to raise temperatures into the upper 30s in most spots. So the precipitation falling with the front is falling mostly as rain.

But once the front passes, colder air will filter back in to the region overnight, likely changing whatever is falling back to snow, but now it looks like there's not much moisture behind this front to play with, so snow showers are expected to be fairly isolated and light.

Any area could still see a little snow overnight -- especially away from the water -- but accumulations are expected to be an inch or so at most, so not enough to warrant a Snow Advisory. That said, it wouldn’t surprise me to hear of a few isolated spots that get 2-3" of snow if a snow shower parks over someplace.

(Lest we forget, this is a lot of snow in the mountains. A HEAVY SNOW WARNING remains in effect until 6 a.m. Sunday for as much as 12" of new snow in the Cascades.)

Sunday and Monday: Hit-And-Miss Snow Showers

Sunday will feature a sort of a snow lottery, where we'll see scattered snow showers roaming around, dumping perhaps 1" in random areas across the region.

Once we get farther into the afternoon, temperatures will warm into the mid-upper 30s, turning some of these showers back to a mix or just plain rain, but then we'll go back to snow showers Sunday night as the sun goes down and the temperatures drop closer to freezing.

We will have to watch Sunday night as if we get clearing spots between the showers, that could allow temperatures to drop below freezing, presenting some icy road concerns for Monday morning.

For the daylight hours of Monday, we'll be in a similar pattern as Sunday -- random hit-and-miss snow or rain showers as another weak weather system drifts through. Again, any shower could still put down an inch or so if you get under one of them.

Highs both days will be in the mid-upper 30s, with lows around 30 Sunday night.

Tuesday: One Last Gasp of Snow?

If you were unlucky (lucky?) enough to miss the snow by then, there's still one last chance during the grand finale.

Forecasting models show that aside from our weak system on Monday, another reinforcement of arctic air will pool behind the mountains in interior B.C.

But they don't agree on whether or not Monday's system will pull in some more of that arctic air out of the Fraser Valley and into Western Washington.

That's important, because we have a much wetter cold front approaching the area early Tuesday morning. If that arctic air gets pulled in here, that could make for a widespread, accumulating snow Tuesday morning before gradually changing to rain.

But if the arctic air doesn't get pulled in, it's either a brief snow to rain, or just plain rain through the day. It will bear watching.

We could see enough chilly air behind Tuesday's front for perhaps again dealing with a few snow or mix showers on Wednesday (an encore?) but by Thursday we definitely look warm enough for rain.

For those that are daring and want to wade into the world of complex meteorology, read on as to what we were thinking earlier about this storm, read on. However, these factors have now passed and are generally moot to the current forecast..

The Meteorological Mumbo-Jumbo (Left over from Friday's story)

Going to brave the explanation? Good for you. Nintendo's "Brain Age" game has nothing on this.

First, a quick recap: We have two weather systems heading our way from opposite directions -- sort of like boxers meeting in the middle from their respective corners and we are the sponsor logo on the mat.

The first one is some remnant moisture moving north from a storm currently spinning around in northern California. That moisture is expected to move north through Oregon and reach southern Washington by mid to late morning Saturday. The second is a weak cold front moving south out of British Columbia.

The Set Up:

There are two main factors here that will determine the air temperature and whether you get rain or snow, and two minor factors that will influence the two main factors.

The main factors are: humidity and precipitation intensity.

First up, humidity. Having dry air in place is an important factor in getting snow because it can allow for snow even if the ambient temperature is in the upper 30s or low 40s. When snow first begins to fall into dry air, that snow will evaporate. But the process of evaporation takes energy. Sapping energy from the air causes it to cool, dropping its temperature. So as this process churns away, the temperature will drop, but the humidity will rise as you add more evaporated moisture to the air content. The drier the air is at the beginning, the farther the temperature can fall during this process. (This is also known as "wet bulb cooling".)

You can get a good gauge of this process by checking the temperature and dew point (the temperature at which air becomes saturated). You can find that at this link. Dew Point is under "DP". If this evaporation process is efficient, you can roughly take the midpoint of the temperature and the dew point and get an idea of how far the temperature can fall.

For example, if the temperature is 38 degrees, but the dew point is 20 (about the general range dew points were in Friday morning), you can see the midpoint is 29 degrees. So if it were to begin precipitating in Seattle in that circumstance, the temperature could drop as low as 29 degrees or so, making it snow despite being 38 a short while earlier.

(Note that usually when it's 38 around here, we have our usual moist, marine flow that keeps dew points in the mid 30s, taking the evaporation cooling out of the equation and keeping it as rain. But this week, we've had a dry northeasterly wind that has kept humidities low.)

But wet bulb cooling needs some help, and that brings up the second factor: precipitation intensity. We need to have a decent amount of oompf in the precipitation to get that cooling engine going. If it's a really light snow or flurries, it won't evaporate as much or as quickly, which means this cooling engine won't be very efficient and the temperature may not drop as much.

On the other hand, if you get a really heavy snow shower, that can really get that evaporation going and drop the temperature quite a bit. This is typically how snows in the Convergence Zone work when it snows in Everett/Lynnwood despite being in the low 40s across the rest of the region. The snow along the Hood Canal usually benefits from this as well.

The Specifics For Saturday

The daylight hours of Saturday ended up being mostly rain for everyone even with those earlier factors in play.

We had the dry air in place (check) and some moisture moving in (check). However, there were those two minor factors that worked against snow today.

The first was a warmer, south/southwest wind that the front drew ahead of it. This not only increased the temperature a bit, but it also added some humidity to the equation, making that middle-ground temperature warmer.

This is pretty much what happened to keep most areas as rain during the day Saturday. We had enough south wind to warm us up a bit -- even more so in the middle layers of the atmosphere. So even though we had some of the wet bulb cooling in play and temperatures near the ground were cold enough, the middle layers of the atmosphere were warm enough to melt the snow into rain. (This is how you can get freezing rain -- having a cold layer near the ground so the rain re-freezes when it hits that cold layer). We had a few isolated reports of freezing rain, but nothing major.

The second is that the moisture moving in from the south didn't have much intensity to it. So it did not snow hard enough at the base of the cloud to drive the snow levels down to the surface, leaving us with a rain or a mix.

But just because it didn't snow during the day Saturday (which was marginal to begin with) doesn't mean to give up on snow overnight or the rest of the weekend.