Rainy & Windy

December 29, 2008

Snapshot  My driveway was finally passable by 4×4 transportation today, that was after my wife and I did 3 stints shoveling out the last 200' over the weekend.  I even have 2 blisters to prove it…pretty cool eh?  I figure another 2 days of melting should allow a 2 wheel drive to go at least downhill, another day or two to get back up.  Life will be good again!  The warm rain over the weekend was amazingly effective at getting rid of the snow.  Here at the station in Beaverton there is no snow left on the ground.  I had 26" which is now down to around 6" at home.

The graphic is one I've shown on our various shows tonight (I've done 3 of 5 so far).  It makes a point;  just because you have a big snowpack in the mountains doesn't mean a flood is coming.  Thick snowpack is just one ingredient for a flood.  Last year there was twice as much in the Coast Range at two different times during the winter.  In fact the 2nd time there was 35" of snow water equivalent on Saddle Mtn. west of Forest Grove was at the end of April!  No flood because we never had heavy, warm rains on top of the snow.  We don't see that coming anytime soon either.  Lots of weather systems the next 10 days, but the freezing level jumps up and down with each cold and warm front.  We can use lots of rain because our monthly total is only about 1/2 of average, continuing a trend that began in January.  I'm shooting from the hip here, but I think August was the only month this year with above average rainfall.

None of the systems this week appear to have the correct positioning or strength to give us a windstorm in the Valley.  The Thursday night-Friday system has been taunting us for a few model runs.  The latest 00z run of the WRF-GFS would give us 15-17 millibars EUG-OLM pressure gradient for a very windy night, but probably no gusts above 50 mph.  It has the low center getting close to 960 mb. as it moves inland over central Vancouver Island, a bit too far north for a big storm here.

Okay, time to move on…got to get a few graphics organized for the 10pm show…Mark Nelsen

White Christmas!

December 25, 2008

Snapshot Merry Christmas!  Here we are again…it's Christmas in Portland and it snowed…who would have thought it could happen in two back to back years!

That nice little band of solid snow that dropped through the Portland Metro area this afternoon dropped anywhere from 1/2" to 4".  Officially .8" fell at the NWS office on NE 122nd Ave.  There is still 10" on the ground there, and 5" at PDX.  That 5" at PDX still blows away any previous snow on the ground measurements for Dec. 25th.  The next largest amount was a trace.  So now you can once again tell your kids about the White Christmas of 2008.  Oh, and now it's the 2nd snowiest month in PDX snow history, outranked only by January of 1950.

I didn't work yesterday, but when I left Tuesday night, I expected 1-3" of snow Christmas Eve morning before an afternoon warm up.  Others were very skeptical, but the south wind did the trick again, pushing PDX to 39.

It also appeared a surface low would come quite close to us on it's way SE for today.  That did happen, although the low center was farther offshore.  We still had one nice wrap-around band come through the area this afternoon which pretty much saved it from being a forecast bust.  I had figured maybe 2-4", which was high for most of us.

So now it's on the westerly flow after leftover snow showers tonight.  The flow through the Columbia River Gorge is light westerly right now, so we'll have no problem warming the airmass tomorrow for a quick changeover to afternoon rain.  Yes, we'll see a mix just about anywhere in the morning, but then it's on to a cold Friday afternoon rain.  Increasing southerly wind with a warm front tomorrow evening actually pushes our temperature up and by Saturday AM we may be well into the 40s.  Oh man…I can't imagine what kind of noise that snow on the metal roof will make when it slides off.  I'll try not to stand under it.  That's if I don't get speared by the 4 ft. icicles hanging off the gutters…apparently I need to get better insulation in my attic because my snow was melting on the roof pretty well yesterday even with a temp in the mid 20s.

Speaking of the home front…I got an additional 3" yesterday morning, then 6" again from yesterday afternoon through this afternoon.  That brings the snow depth to an amazing 26"!  I have never lived in a place that had so much snow on the ground.  My winter total (the last 11 days) is up to 42.5".  Now if we could just do the same thing again the last week of January AFTER I buy some sort of snow blower, that'll be cool.  But for now it's back to lots of rain and south wind.  We'll keep a close eye on developing low pressure systems…hopefully no big windstorms on the way…Mark Nelsen

Snow Totals Ver 5.0: Christmas Edition

December 24, 2008

Really, this should be it this time around! It's getting a bit ridiculous. Looks like everyone gets some between now and Christmas afternoon. Put in your snow totals on this post through Christmas.

1.  New Snow (starting Christmas Eve morning, Wednesday)

2. Total snowdepth

3. Location

No other comments or discussion in this post please.  Keep discussing weather in other posts.

Between Snow Storms Today

December 23, 2008

DSCF0012 I was a bit negligent in posting yesterday…probably due to exhaustion and the fact that forecast-wise there wasn't much to talk about for today.  The other is that I REALLY wanted to get home due to generator issues and other things (2 kids stuck in a house alone with my wife).  So at midnight I made it down my rural road which had one lane plowed with 3 foot berms on each side.  I get to my driveway and…nowhere to park!  My wife had left the snow shovel, so at midnight I spent 30 minutes digging through the (relatively light) snow, just enough to nuzzle the SUV into a little parking spot.  Then it was a 500 ft. trudge through about 2 feet of snow in the pitch dark, stumbling into the powder, in jeans and hanging onto bananas and a bottle of wine.  You can imagine the scene.  No electricity at home and the family was camped out by the woodstove all asleep like it's Christmas Eve!  To make this long story short, the power just came back on and internet access is restored.  I am just amazed at the snow depth.  I still have 21" on the ground about 2 miles east of Corbett at 1,000' elevation…I don't get much drifting here because of very little wind, so I assume that there must have been 22-24" before it compacted the last 24 hours.  That includes 13" on top of the thin ice layer Sunday too.  You see the picture…that's my dog;  the Prius is on the left and the Odyssey minivan is on the right.  They won't move for a long time!  I'll put some other pictures in the viewer photos on the sidebar.

I haven't spent the usual enormous amount of time staring at maps today, but enough to confirm what I was already thinking, with a few changes…

Offshore flow continues tonight and early tomorrow ahead of an approaching weather system…keeping us relatively cold through morning.  I see temps are approaching freezing in spots at 1pm, so that forecast is looking good.  I doubt we'll see a dramatic drop tonight, just staying in the mid-upper 20s.  That sets us up for some snow in the morning as precipitation from the approaching California storm merges with the cold front coming in from the northwest.  Last night I said 2-4" and at this point that seems a bit high, considering that the freezing level should rise to about 1,500' from 4pm tomorrow through early morning Christmas Day, and the heavier precip comes with that slight warming.  Maybe 1-3" is a better bet.  Christmas Eve itself (tomorrow evening), should be a bit sloppy with a rain/snow mix due to a good southerly wind blowing up the Valley.  Not exactly a real warm wind, but enough to change those of us below 1,000' to that sloppy mix.

Then the fun returns Christmas Day itself.  Looks like a surface low slides right over the top of us or just to the south during the morning hours, turning our surface wind easterly again (cold), then light north by late in the day.  There is a good burst of precipitation at the same time…SO…I think Christmas Morning we'll probably see widespread 2-4" snowfall, with some spots up to 6" if we stay chilly enough.  Maybe Steve Pierce can confirm, but I don't think we've ever seen such a White Christmas! 

I think the higher elevations and Columbia River Gorge could see another foot of snow from tomorrow morning through Christmas night!  Down here in the metro area I see snow, then rain/snow mix or all rain, then more fresh snow Christmas Day.

I didn't look too far beyond Christmas since I spent the morning shoveling, BUT, it's obvious there is going to be a quick change to mild and wet westerly flow late Friday and the weekend.  50 degrees isn't too far away for those of you tired of the snow…

9pm Update:  This will be brief, since I need to get organized for the 10pm show, but I see precipitation is moving in quickly this evening.  Some below have mentioned the KPTV tower temp is above freezing at the top.  Yes, but just barely and the dewpoint at that elevation is below zero.  That means evaporational cooling should drop temps down below freezing at that elevation soon after the precipitation starts falling.

Just looked at 00z maps…there seems to be a slight northward trend in the 00z WRF-GFS and 00z MM5-NAM in the low pressure center location for Christmas Day.  The 00z NAM would give us no snow, but the 00z WRF still could.  Just another wrinkle in the forecast. 

What continues to be very clear in the longer range is that the snow threat ends Friday.  After that it's back to wild, wet, and warm Pacific weather systems.  Enjoy the snow while it lasts!

Mark Nelsen

Mild Temps Continue

December 2, 2008

Snapshot Whew…seems like mild Fall temps just don't want to go away.  Once again we made it into the mid 50s today.  And check out the morning low!  We couldn't even make it down to our normal high.

I would like to move on and talk about fun and exciting weather in our future…but there isn't any.  But I'll try.

There is a quite a dry airmass gradually working south through Eastern Oregon this evening.  Check out the dewpoint drops in the Okanogan Valley through the day as a north wind moved in.  This drier and cooler air fills the Columbia Basin tomorrow and Thursday.  Of course then it'll come through the Gorge, clearing skies for Thursday and Friday.

Not much to say beyond that except the 7-10 day forecast looks relatively quiet.  MAYBE more activity towards the middle of next week, but I'm skeptical for now…Mark Nelsen

December Starts Warm

December 1, 2008

Meadows_12_01_08 Nice image for September isn't it?  This is the base of Mt. Hood Meadows on December 1st.  There SHOULD be a decent amount of snow at this spot (5,400') this time of year, but apparently the ski season is going to start quite late this season.

Before anyone gets too worked up though, remember what happened the winter of 1989-1990.  Very little or no snow fell at pass elevations through the ENTIRE month of December.  Government Camp officially received no snow that month;  the only snowless December on record there.  Then precipitation arrived right around January 1st and the floodgate (or skies) opened up.  Frequent storms moved in for most of the following 6 weeks.  At the same elevation as the picture above (Mt. Hood Test Site), the water in the snowpack went from 7.40" to 31.30" in the month of January.  About 23" of melted precipitation fell, raising the 18" on the ground January 1st up to 105" at the end of the month.  The point is, that the very slow start to the ski season sure doesn't mean it'll be a bad year.  Of course that's what happened in 2000-2001, so who knows?

For the rest of us, the clear message on the short and long range weather maps is slow, slow, slow and boring, boring, boring.  More fog, sun, and occasional east wind.  The first ten days of December are going to be uneventful.  But we can always hope that the arctic blast of the decade is just 5 days after that right?  All I really want is a freeze.  I still have not hit freezing at my home up at 1,000'.  I've had frost on the deck a few times, but only 33 degrees.  None of my plants show any sort of frost damage.  The banana plants are still green and nasturtiums are still growing slowly.  I started early today (8am) and visited four schools down the Valley.  Mt. Angel, S. Salem, Scio, and N. Salem were the stops and then it was back to Beaverton for work.  So it's time to go home, I'll leave the evening forecast in the capable hands of Drew Jackson…heck, maybe I'll even hop on the blog when the 00z comes in just for fun…Mark Nelsen