Complicated weather: Snow day, freezing temps, and a lot of rain
Demonstrating to Inner Southeast Portland residents that winter is really here, snowfall on the morning of February 5 paralyzed traffic, caused a "Snow Day" closing of all area Portland Public Schools, and hampered businesses.
The one-day blizzard of unusually dry and fluffy snow was the result of "cold meeting moist", explained National Weather Service Portland (NWSP) Meteorologist Colby Neuman to THE BEE, while looking at the computer displays at his East Portland offices.
"We have cold air that's been coming down south from Canada and Alaska, and picking up just enough moisture coming east off the Pacific Ocean, to bring us some low elevation snow," Neuman said.
Unlike other years, in which meteorologists were apparently caught by surprise, they accurately foretold this weather event. "In this case, our weather models were hinting at the strong possibility of low elevation snow a week before the snowfall."
Snowfall takes the right combination of conditions, Neuman explained. "If we have too much cold air coming from the interior, we tend to dry out and it's just cold. If moisture comes in significantly over the ocean it tends to modify [weather conditions], and warm up just enough that we see a few flakes in the air, but it'll be mostly rain.
When it's a week out, we don't necessarily trust any model solution," Neuman pointed out. That weekend, the snow turned to slush, and then froze in sub-freezing temperatures.
As more-typical rainy winter weather returned, Portland Meteorologist Scott Weishaar reviewed the forecast with the actual conditions in the area. "We had a battle between the warm southerly flow up from the Willamette Valley with the cold flow coming from the east, through the Columbia Gorge; the warm southerly flow won out."There was plenty of precipitation, Weishaar observed, "but the cold air boundary line stalled further to the north and west of Inner Southeast Portland, so it didn't turn out to be quite as cold as anticipated.
But, the whole West Coast has been cooler and wetter than usual lately (snow in San Diego??) -- and there's just no telling what the rest of the winter may have in store for us.