Final Update: 10:30pm

January 11, 2011

Warming up nicely overhead with the top of the KPTV Tower (1,900′) above freezing, so we’ll see the areas of ice pellets start to dwindle and now it’s on to just liquid rain melting on contact in about 1/2 of the metro area where it is below freezing.   What a mess on I-205 in East Portland right now…traffic at a standstill or barely moving in a couple spots.  Looks messy on the eastside!

Warming is just approaching the Eugene area with a station at 1,200′ near the city suddenly jumping into the mid 40s.  I still see no reason that we won’t see a surge of southerly wind working up the Valley the 2nd half of tonight as models show with such a deep area of low pressure to our northwest. 

That said, there will be plenty of ice leftover east of I-205 for at least the first part of the morning commute.  I’ve found in the past that unless we get a ton of thick ice, roads improve pretty quickly with temps warming into the 40s.

Time to head home soon…I’ll drive slowly.  Freezing rain and 25 degrees there.

Hey, those long range maps are interesting.  Wait, let’s not start that yet…

Chief Meteorologist Mark Nelsen

7:30pm Update: Roads Icing Up…

January 11, 2011

Lots of icy streets out there since we made the change from snow to mainly freezing rain around 6pm.  Radar looking very dry the next couple hours now that the first band of precipitation has moved through.    I just scanned all the ODOT cams and don’t see any freeway issues, probably because of the thousands of gallons of gunk laid down on roads the last few days (hate that on my windshield).  Side streets a different story though since most of the Portland/Vancouver Metro area is at or below freezing right now, with coldest temps on the hills and areas closest to the Gorge.  The only spots above freezing appear to be well north of the Columbia River in Clark County and south of I-205 in the south Metro.  The Gorge wind is doing the trick…with the strongest gusts of the winter so far out at Corbett around 7pm…65 mph!  The new Vista House wind sensor was just fine physically as of noon (I drove by), but the signal is not being received inside.  Plus it appears the computer stopped sending anything around 3pm.  Would have been nice to see 80-100 mph gusts out there this evening!

There will be no significant warming in the lowest 1,500′ of the atmosphere in at least the next 6 hours.  That includes pretty much all of us.  Note Eugene doesn’t even have a southerly wind yet, and our RPM has slowed down the arrival of the big warm south wind until about 4am.

As a result, when heavier precipitation arrives sometime after 10pm, there should be a significant glazing on most Metro-Area roadways.  Of course most of us will be either at home or asleep when that happens!

It sure wasn’t a snow event, but at least everyone got to see some frozen precipitation of some sort this evening, and almost all of the Metro Area got to see some snow too.

Be careful out there this evening!

Chief Meteorologist Mark Nelsen

Snow Picking Up: 5pm

January 11, 2011

From our ODOT cameras it appears that snow is starting to stick now in the metro area as the radar screen fills in.  We ARE getting some evaporational cooling too…temps are near/below freezing in most of the Metro Area.  If you don’t want to drive on snow or ice you should get home quickly in the next couple of hours.

Chief Meteorologist Mark Nelsen

The Fun Begins! 2pm Update

January 11, 2011

This is getting real interesting this afternoon.  Several things going on.

First, if you are not a weather geek, be aware that there will probably be some icy spots for the evening commute.  I doubt we’ll get a raging icy mess, but definitely cold enough in about 1/2 of the metro area to see light snow or glaze ice in spots after sunset (5pm).  Things are moving slightly ahead of schedule.  If you’re worried, go ahead and head home now just to be safe.  It might just be flurries with little accumulation.

1. First band of precipitation is a bit early, light, but it appears some precipitation will show up over the Metro Area in the next 2 hours.  It’s been flurrying or snowing down the Valley and now even at Hebo (the town, not mountain) in the past hour.  Radar shows that band moving towards us.

2. Notice I said snow…again the mesoscale models are not handling the lowest atmosphere very well.  Check out the top of the KPTV Tower…I’m estimating it’s around 27 up there right now.  Models said low-mid 30s by now.  Low level airmass is still real chilly.  If it can snow in Eugene and in a valley at the Coast, it’s definitely cold enough to be snow here.  Good job by the NWS if that occurs.

3. Our 18z RPM (similar to WRF-GFS) has a more generalized band of precipitation moving over NW Oregon in the 5-7pm period, then heavier stuff after 10pm.  That’s a move forward in time by several hours.  Maybe that’s what we’re seeing on radar now.

4.  Southerly wind switch with a rapid jump in temps still on for after midnight…I have a feeling kids WILL have school in the morning, except in the Gorge.  The best I can get you kids is a two hour delay for most of town.