WEATHER: Arctic front headed our way
By JAYSON JACOBY
The merciless intruder lurks today in Northwestern Canada but soon it will slink south.
And Baker County lies directly in its frigid path.
Cold weather is coming.
Colder, perhaps, than anything Baker County residents have endured since Jan. 5, 2004, when the temperature at the Baker City Municipal Airport bottomed at 21 degrees below zero.
The National Weather Service isn't predicting temperatures quite so polar as that this week.
But the impending cold snap could well surpass this winter season's lowest temperature 4 below zero on Nov. 29.
In any case, we've got one last day to sift through the dusty detritus in our closets and assemble our wardrobes of wool, down and fleece.
Today will feel balmy by comparison to the rest of the week.
The Weather Service predicts the temperature will rise to 42 in Baker City about eight degrees warmer than average for early January.
But this springlike respite will survive about as long as a rat in the anaconda's cage at the zoo.
Or, to put it in more appropriate terms, about as long as a seal pup in the polar bear's lair.
Around dawn Wednesday a cold front a weather term that's particularly apt in this case will push south from Washington into Oregon, said Jeanne Allen, a meteorologist at the National Weather Service office in Boise.
Soon after the cold front passes, mild south winds will be replaced by northwest gusts that blow the initial batch of chilly Canadian air into the region, Allen said.
Sometime early Wednesday the temperature should dip below freezing in Baker City. And there it will stay, probably until Monday at the earliest.
The Weather Service forecasts a high of 29 degrees in Baker City on Wednesday.
The truly frigid stuff, though, won't arrive until Thursday, Allen said.
A second front, what meteorologists call an "arctic front," will usher in a glut of that Canadian air.
For perspective, consider that the temperature this morning at Old Crow, a town in Yukon Territory, plummeted to a pipe-busting 41 below zero.
Dawson was 37 below.
We won't get that cold, Allen said.
"As the air starts to move south it will modify somewhat," she said.
In fact, the Weather Service predicts low temperatures at Baker City from Thursday through Monday will range from 2 degrees below zero to 12 above.
However, Allen cautions that temperatures could be 10 degrees colder than the forecast if a couple inches of snow covers the ground before skies clear on Friday.
"Snow cover can have a great effect on temperatures," Allen said.
During the day, snow, which at least in its unsullied state is white, reflects most of the sun's heat back into the atmosphere. Bare ground, by contrast, and in particular dark surfaces such as blacktopped streets, absorb heat.
When the sun dips below the horizon the ground cools. Meteorologists call the process "radiational cooling," and it's more dramatic, in terms of temperature change, on clear nights. Clouds act as a sort of blanket that holds heat close to the ground which, after all, is where most thermometers are.
Although Allen said Weather Service forecasts are confident that the cold snap is imminent, they're not so sure about snowfall.
The arctic front is rather dry, she said, because its path is over land rather than over the Pacific Ocean. Storms that cross long fetches of sea the infamous Pineapple Express that sometimes drenches Oregon, for instance are much more moist than are arctic fronts.
Nonetheless, the pair of storms should deposit at least a dusting of snow over Baker County, and possibly a few inches, Allen said.