January, February, and this first week of March have been very quiet weatherwise. But one very strong storm is developing to our southwest. It’s going to be a classic “southwester” as the deepening surface low races almost straight north along the 130 west longitude line. Typically for a widespread windstorm in our area we need a deep low to move along this track EAST of that line, so this one will be pretty far out. But it’ll bottom out down around 970 millibars as it moves towards Haida Gwaii or the northern tip of Vancouver Island. That’s a strong storm and one capable of giving widespread 65-75 mph gusts at the coast. I wouldn’t be surprised to see an isolated spot or two (not Mt. Hebo or Meares Hill) around 80-90 mph.
After a strong easterly Gorge wind in the morning (gorge and east metro), a southerly pressure gradient will set up in the Willamette Valley in the late afternoon and evening. That’s when wind will pick up in the Valley. I sure don’t expect a damaging wind in the valley, but breezy and rainy for the evening
One would think that we could get a decent windstorm with the extremely strong wind overhead tomorrow night. The WRF-GFS cross section shows 90 mph wind over Portland around 10pm-1am tomorrow night; one of the only times I’ve seen an 80 kt. wind barb overhead.
But the isobar orientation is not lined up correctly down here at the surface since the low is way offshore. Thus the wind won’t get too strong. It would be a totally different story tomorrow night if we had a strong south to north pressure gradient in the western valleys.
Chief Meteorologist Mark Nelsen