Ice/Snow Recap: Things to Learn

January 12, 2011

This is for the hardcore weather groupies:

I just saved maps, observations, and other info on our little event last night so I could look look a bit closer in the future when the weather is slower.  Here are a few thoughts on the past 24 hours.

1. In general I think our forecast 24 hours ahead of time was pretty good.  We said most of the event would be during the night, it would be mainly freezing rain (or all), and the morning commute shouldn’t have any serious issues.  Plus we said most of it would occur after the evening commute (partially correct).

What we missed:

1. Snowy start…only because we had very light precipitation to begin with did we avoid a snowy evening commute.  The precipitation was a bit ahead of schedule AND it was snow.  We could have easily seen a quick dump of 1-2″ that would have made for a December 29, 2009 repeat.  Atmosphere overhead stayed far colder than models showed.  At 4pm, it was around 26 degrees on the top of our transmission tower in the West Hills (1,800′), the highest resolution model we have (4km WRF-GFS) showed the temp should have warmed to around 37 degrees with wetbulb temps above freezing.  That’s pretty bad…models will have to be higher resolution to handle cold air outflow from the Gorge better.  At least a close eye on those towers will help.  It did about 10 days ago when we had the spotty freezing rain.

Things to remember in the future:

1. I (and everyone else) needs to remember that you don’t get much freezing of roads (that aren’t initially below freezing) until the air temperature gets down to about 30 degrees.  I had forgotten about that since the east metro area hasn’t had signficant ice in 3-4 years.  My drive across the region at midnight seemed to confirm that.  Here in Beaverton it was 31 or 32, but no ice on roads, just everything else.  In fact now that I think about it, we don’t get freezing rain that affects traffic (much) west of the West Hills unless it’s associated with one of the big cold storms.  Sure, a little ice, but it would have been nice to say that on-air.

2. If the south wind isn’t forecast to arrive until 1-4am (as the best models showed), the temperature won’t really budge until that time.  We don’t get “slow warming” in the middle of the night with easterly wind blowing or calm conditions.  Not that there was any huge forecast error here, but something to remember.

3.  When we have a very warm atmosphere overhead, the temp change will be sudden in most areas.  PDX and TTD jumped 10-15 degrees in just one our this morning.

That’s all for tonight…we’ll talk heavy rain tomorrow night I’m sure.

P.S…Yesterday (January 11, 2011) was the busiest day yet for this blog…79,000 visits in 24 hours!

Chief Meteorologist Mark Nelsen

It Lives! Crown Point Wind Gauge

January 12, 2011

The “new” old wind gauge the Oregon State Parks people and I put up on Vista House (temporary) is still there.  I drove by around noon.   Solid sheet of ice the last mile around those curves.  But it was a sweet sight to see my little buddy lazily spinning it’s cups on a 5 mph southwest wind.  As if nothing had occurred up there the last 24 hours…  Here’s another picture showing the east-northeast side of Vista House glazed in ice.   It’s only my camera picture, so it looks a bit monochromatic, but you get the picture, notice far less ice on the side the anemometer is on.  Apparently the wind comes in a little more from the NE than I thought (as opposed to ENE).

There have been a few misconceptions or just questions about what is going on with that sensor so here are the pertinent details:

1.  It sends the signal wirelessly to the VP console down in the basement.  On even that nice weather day the console was having trouble receiving the signal through concrete, so I knew from the beginning we may or may not actually receive data with the old, weak VP sensor (new VP2 signals are far stronger).

2. It couldn’t receive a signal for the first two days, then for some reason it operated for maybe 12 hours when the wind started up on Monday night.  Nothing since. 

3. The sensor has to come down the first week in March; that’s when the place reopens for the season and a nice little old lady doesn’t need to be stumbling across a 120lb chunk of concrete with a pole sticking out.

4. I’ll check in on it, add a new battery etc…but most likely it’s just going to be sporadic the next 6 weeks until a new one with a stronger signal is purchased.

5.  This was really a test to see if it could all come together.  Other than the wireless signal issue it appears to have worked.  I appreciate all the offers of help from my fellow weather geeks over the past few months, but the job was really pretty simple.  So I just dealt mano y mano with a State Parks person.

Chief Meteorologist Mark Nelsen

Best (Worst) Ice Storm in 2 Years

January 12, 2011

It’s finally over this morning, the eastern suburbs of Portland have warmed dramatically between 9-10am as the cold Gorge wind grinds to a halt and the warm Willamette Valley southerlies take over.  What an icy night east of downtown Portland.  We haven’t seen ice that thick in the Metro area since at least early January two years ago…maybe longer. 

It was an interesting event with respect to model performance and forecasting (they did a horrible job).  I’ll post about it later today.

On the way to work I’ll drive by Vista House and see if that new sensor is alive.  The windspeed at Corbett hit 70 mph last night, so 80-100 mph was a good bet up there.

Enjoy the pineapple and palm tree smell in the warm air!

Chief Meteorologist Mark Nelsen