Downslope Wind Today

December 26, 2009

Solid stratus deck in most of the Columbia Basin...notice it's pushing up through the "Lava Butte Gap" south of Bend.

We’re in more of a downslope wind event today compared to the last two days.  That’s where we get wind coming right over the Cascades as well as through the Gorge.

1.  Cascade west slope locations are significantly colder than yesterday at this time.  Wanderer’s Peak SE of Estacada was around 40 at this time yesterday; it’s 27 today.  Horse Creek SE of Molalla was 64 for a high yesterda at 3,400′.  Today it was 30 degrees colder!  Only 34 for a high.  Cold air is spilling right over the top of the Cascade crest from the cold pool (shows as low clouds on satellite image) east of the Cascades.  Notice most of Clark county is windy today too; yesterday it was calm in most spots.

2. Peak wind gust last hour on the Glen Jackson bridge was over 50 mph, but Corbett (in the west end of the Gorge) has backed off with only gusts to 40 mph in the last hour.  Steve Pierce was up at Crown Pt. at noon and says a person recorded a gust to 74 mph.  Real windy, but not as wild as you would expect up there.

3.  Wind direction at PDX is east…a true “gorge wind” at PDX is from the ESE, or about 120 degrees.

10:30pm Update:  00z models are looking drier for tomorrow…good news.  I took the gamble that we probably won’t see any moisture tomorrow in the forecasts.  I DO notice the 00z SLE sounding is pretty darn close to snow.  So if we see something it could be either a sprinkle OR a flurry.  I still think we’ll stay dry anyway.  Our RPM model shows a second surge of moisture coming up from the south after dark tomorrow evening, but it tends to be to wet so…well…you get the idea.

Otherwise pretty quiet through Tuesday morning with east wind easing off a bit more.  PDX-DLS gradient has dropped from around 11mb. last night to about 8mb. this evening so the wind has backed off and won’t be nearly as strong tomorrow.

Tuesday COULD be interesting since we still have easterly flow as a strong front moves inland with lots of moisture.  This might produce signficant snow in the Gorge and maybe some spots from Portland north could be a mix if the precipitation moves in early.  Definitely more active weather on the way later in the week too.

Mark Nelsen