It’s official, weather service issues an ice-storm warning

To no surprise, the National Weather Service has issued an ice-storm warning for much of Western Washington until 2 p.m. Thursday.

By Dean Radford • January 19, 2012 2:24 pm
The American Flag was about that was showing above the snow at the lot at Brad Brotherton Cadillac GMC in Renton.
The American Flag was about that was showing above the snow at the lot at Brad Brotherton Cadillac GMC in Renton.

To no surprise, the National Weather Service has issued an ice-storm warning for much of Western Washington until 2 p.m. Thursday.

The weather service is also warning that warming temperatures will increase the chance for minor flooding on some rivers in Western Washington.

Pools of water are already forming on roadways as snow and ice clog drains.

Ice accumulations of a quarter-inch to three-quarters of an inch are expected, making for hazardous driving conditions.

The extra load is causing tree limbs to snap and trees to fall, one of the main reasons that 10s of thousands of people are out of power Thursday.In such conditions, it’s recommended to not travel at all or if travel is necessary, it’s suggested to bring extra food, water, clothing and a flashlight.

But snow is still in the forecast.

In Renton rain will fall until 4 p.m., when it’s possible snow could fall until about 10 p.m. according to the weather service.  The snow level will be about 600 feet, with 1 to 2 inches of new snow possible. However, tonight the snow level will rise to about 1,100 feet.

The low Thursday is forecast for about 33 degrees. Come Friday, temperatures will rise even more, to a high about 48, with a low of 42. Rain remains in the forecast.

That pattern will continue through the weekend; no snow is forecast.

The weekend storm could dump one-half inch of rain to 2 1/2 inches of rain  below about 4,000 feet. At the same time warmer temperatures will melt the lowland snow.

The weather service is evaluating how much water is in that snow.

Some rivers could reach flood stage, including the Chehalis and Skokomish rivers. Any flooding is expected to be minor.

The Green and Cedar rivers are both controlled by dams.

“This will be a tricky situation to forecast and uncertainty that there will or will not be flooding is quite high,” according to the advisory. Rainfall and the water content of lowland snow will determine the level of flooding.

“River models do no always handle these situations very well, so specific river forecasts may not fully indicated the existing flood risk,” according to the advisory.