Downslope Wind Today

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

A Chilly, Crisp, & Windy Christmas

I’m really tired of staring at that radar dome each time I check out the blog, so here’s something fresh.  I’ll be working again Christmas afternoon/evening after a nice 8 day break.  So the biggest question I have is: what lies at the foot of the statue?  Anyone with any insights on that can let me know.  I’m “Losted” out after watching the whole season in about 5 days.  So let’s move on to weather.  Three items of note:

1.  East wind is going to begin raging tonight and continue through the weekend…strongest tomorrow night and Saturday morning.  Gradient is up to 6 millibars at 1pm, giving gusts over 50 mph now at Rooster Rock and Corbett sensors.  A gradient of 10-12+ millibars is likely by tomorrow as much warmer air continues moving in overhead over and west of the Cascades, capping a cold airmass moving westward.  This setup with 850mb temps up to +8 overhead really “squeezes” the flow through the Gorge.  Add to that an approaching surface low from the southwest tomorrow night/Saturday and we get very strong wind gusts, probably 65-70mph at the west end of the Gorge and 40-50 mph Troutdale/Gresham areas.  Not a damaging event like last January…we had 850mb temps up around +17 then!  Maybe a Saturday midday Vista House meeting???

2. Freezing Rain Saturday night in the Gorge and maybe far eastern suburbs too?…IF we get moisture up here, it’ll be cold enough for freezing rain, but that’s a big IF.  Most likely it’ll stay dry.  See item #3

3. El Nino dry and mild conditions continue until further notice.…Has anyone noticed that we’ve seen no real westerly flow with a good Pacific Jet since Thanksgiving Day?  We’ve either had split flow over the East Pacific/Western USA, ridging right over us, or ridging just to our west (cold spell) for most of the time.  And models show the same into the first week of the New Year.  Very pathetic looking if you want active weather.  Both the GFS and ECMWF show another possible warm rain episode for the mountains around 8-10 days from now.

Merry Christmas!

Chief Meteorologist Mark Nelsen

Coastal Radar is Coming!

3 Years from now a new NWS radar will be scanning the skies over the Washington and N. Oregon Coastline.

Great news on Cliff Mass’s blog this morning.  Apparently the much-needed coastal radar is included in the final bill signed by President Obama recently.  So everything is on track for a new radar to be installed somewhere on the South or Central Washington Coastline in less than 3 years from now.  Most likely within 40 miles of Aberdeen/Hoquiam.  This will finally get rid of the big hole in coverage to our northwest.  I call our part the “Astoria Hole”.  It’s much worse on the S.W. side of the Olympics…almost no coverage there. 

The current placement of the Portland radar is the best that could be expected back in 1995 with one radar in N.W. Oregon.  It was put up at about 1800′ on Dixie Mtn. to the southwest of Scappoose.  Great coverage of summertime thunderstorms and wintertime rain/snow in the Cascades and Valleys, but the compromise was horrible coastal coverage.  Keep in mind that we can’t see much of anything along the coastline below maybe 8,000-10,000 feet.  Sure we get the big picture, but no low-level details.  IF a radar had been installed at the Coast instead of the Valleys, our coverage here in the Valleys and Cascades would have been terrible, so the NWS did the best they could here in the mountainous West!

You can read more about it here at Cliff’s Blog.

Chief Meteorologist Mark Nelsen