The fog is gone. Skies are clearing. Full-on sunshine is expected tomorrow and Tuesday.
Why the sudden change in weather?
The answer is blowing in the wind.
Northerly winds from Canada are spreading drier air into the region as they advance southward, lowering the overall dew point (a measure of how moist the air mass is) and effectively killing our chances for any more fog. Fogaholics excluded, that’s a good thing for a city worn down from constant low clouds—Seattle just wrapped up nine straight days of thick fog, with 12 total this month. A typical October sees just seven.
Also carried away into the wind was our impressive dry spell, which ended at exactly two weeks this morning with 0.07 inches of precipitation. That marked the first measurable rainfall in Seattle since Oct. 12—a span of 14 days that goes into the books as October’s longest rain-free stretch since 1991.
With the high pressure ridge that led to the foggy, stagnant conditions now shunted further west, skies will continue to clear overnight as the northerly breezes persist. For most of the Sound, the peak winds have already passed—Sea-Tac clocked in at 32 mph late this afternoon, and Seattle’s Discovery Park reached 33—with areas further east staying much calmer. However, places north of Everett will continue to see somewhat breezy conditions the rest of the night—especially over Whidbey Island and the San Juans, where gusts could reach 40 mph.
The winds taper off everywhere by noon tomorrow, with crisp, sunny skies a good bet for all. With cooler air in place, temperatures will tumble to near 40 degrees Monday morning, rising back to the low 50s in the afternoon.
Tuesday morning starts off even chillier, with lows bottoming out close to the freezing mark around Seattle—the city itself should make it down to the mid 30s, with outlying areas honing in on 32 degrees. Sunny skies will take temperatures back to 50 degrees during the second half of the day.
On Wednesday, a change blows in from the Pacific as a weak front nears the coast, flipping the winds back to their usual southerly direction and pulling in a boatload of clouds. Light rain is likely across the metro area by nighttime, with on-and-off showers holding over into Halloween.
Fortunately, after all the dark weather of the past week, that shouldn’t be too much of a fright.