Snow & Cold Sandbox

December 27, 2010

This post is only for hard core weather discussion, rants, or arguing about models.

Bypass this post if you are a casual visitor, want to know what it’ll do in your neighborhood or have any other questions.  Keep all other discussion in the posts below or I may delete your comment.

Only a few minor rules:

1. No swearing or foul language.

2. No personal attacks.  By that I mean comments about personal life etc… If you think someone’s forecast is horrible, go ahead and point that out.  More important would be to point out why you think so.  I also don’t care if you rip apart my forecast…I’m a big boy.

3. No complaining about someone picking on you in here, if you don’t like it don’t come in.

Merry Christmas

December 24, 2010

I got tired of the 5 day old post even though I’m on vacation.  So here’s something to refresh things a bit.  I’ll be working again starting Sunday the 26th.  Looks more interesting next week…have a good Christmas!

Chief Meteorologist Mark Nelsen

Flurry Storm Wrap Up

December 19, 2010

That worked out pretty well late this afternoon and evening. 

1. Colder than what we had on Saturday morning.  Temps bottomed out at 33/33/34 at TTD/PDX/HIO.  Those temps were 2-4 degrees colder this time around.  Tower temps showed 31 or 32 all the way down to the top of the West Hills.  Seems like the sticking snow was confined closer to the Columbia River and the Gorge.  I was in “upper” Troutdale and everything was white for about 2 hours.

2.  Far less precipitation this time around.  The combination of the colder temps and more precipitation could have easily given a widespread 1-3″ this evening. So in this case precipitation intensity just wasn’t as impressive.

Studded tires are now on; wife is happier.  And good because road is snow-covered above about the 500′ elevation just east of Troutdale.  Maybe 1.5″ at 1,000′ this evening out here.


1pm Update

December 19, 2010

Still looks good for a brief bout of rain/snow mixed or all snow here in the Metro area around sunset or just beyond.  By “brief”, I mean a couple hours or so.  East wind is cranking through the Gorge, gusting to 55mph at 12:11pm in Corbett.  Dewpoints are down in the 20’s or around 30 eastside of town too.  This setup is just maybe 1-2 degrees colder than what we had yesterday morning, but the actual airmass coming out of the Gorge is a few notches colder as well.  I think sticking snow is more likely (at least briefly) near the Gorge.  So I’ll go ahead and predict PDX bottoms out at 35 degrees with evaporational cooling, same at HIO, and 33 at TTD.  Enough to get a dusting in a few more spots, maybe an inch or so at the top of the West Hills. 

Precipitation is moving in a bit more quickly than forecast too.  Looks like it’s just about to Salem. 

If you’re worried about driving, don’t drive after 5pm just to be safe.  But it appears to me any road issues would only be the side roads up on the top of the West Hills and maybe higher Camas, Troutdale, and Gresham areas.  or anywhere else closer to 1,000′.  No matter what happens, it’s mainly gone sometime after 8pm.

I won’t have access to the blog between now and 8pm or so.  Don’t laugh, but I decided that NOW would be the time to finally get the studs put on, and some Christmas shopping too.  So if your comment doesn’t get in…well, you’re out of luck until I get back. 

Chief Meteorologist Mark Nelsen

Snow Flurry-Storm WrapUp

December 18, 2010

I was up like many of you around 4-5am when the heaviest of the precipitation moved through.  In some parts of the metro area it DID briefly change to snow as evaporative cooling did it’s trick.  From what I see in the comments, that was right around the Gateway/I-205 area and way out westside.  That’s a bit closer than I expected in the first location.  A solid 6-8 degrees evaporative cooling is very impressive.

No official airport location had snow, just rain.  PDX only dropped to 37 and Hillsboro 35 at the coolest.  I’m real happy about those numbers (Thursday night’s post).  There was some talk in the comments yesterday about Clark County and areas northof the Columbia River being a favored location for snow.  So much mixing up there that I see some stations were even warmer than the airport.

In general this whole setup was maybe 3-5 degrees warmer than what we saw last December 29th.  The mesoscale models did VERY well with it too.

Now some well-deserved humble talk…that was too close of a situation for snow for a person to be saying “highly unlikely” or it just isn’t going to happen.  That would be me of course.  I still think models were too warm and I’d still make the same forecast again (no snow), but sometimes I think I skew a bit too far the “no snow” direction based on my job.  If deep down inside I figure it’s a 30/70 chance for snow/no snow, I’ll just say no snow to keep it from becoming a significant story because (rightfully so) it doesn’t deserve to be.  For example, how many kids/adults woke up to disappointment this morning after hearing an official forecast for snow early this morning turning to rain?  Hoping for 1″ or so at the top end maybe…

So I like Michael Goss’s comment in the previous posting…the final outcome was somewhere between the NWS forecast and mine.   I think meteorologically both were fine.  And thank God the sudden sighting of flurries happened under the cover of darkness!

Chief Meteorologist Mark Nelsen

Wind is Blowing!…Weather Geek Time

December 17, 2010

I just checked all the obs, models, and various pieces of weather info.  That was after a 2.5 hour  long Monopoly game with the kids…it was painful to not run over to the weather computer to see what was “going on”.  I’m not scheduled to work until the day after Christmas, so I’m free!  I have nowhere to be and no commitments for the next 20 hours.  I can geek out all night long if I want like the rest of you. 

The big picture:  I don’t see anything different or have any changed thoughts about the forecast for the next 10 hours.  Still think snow is unlikely…atmosphere is a bit too warm, and way to much mixing for MOST of the metro area.  As the easterly flow suddenly cuts off when the precip arrives around 4am over on the westside, that’s the best place to be I think.  Maybe Scappose too which is out of the wind zone and jammed up against the 2,000′ hills to the west?  Possible. 

I see the NWS has put up a wind advisory for the eastern suburbs.  The WRF-GFS is  insistent that the easterly wind coming off the south Washington Cascades should keep ramping up for the next 5 hours.  Still shows eastern Clark County with gusts up around 50 mph.  But I see one station in Battle Ground has already had a gust to 46, so will we see a 60 mph?  As mentioned last night, not real excited for gusts over 50 mph south of the Columbia River.

Otherwise the usual Gorge wind has produced a gust to 48 mph in SE Troutdale and 57 mph at Corbett School.  Bonney Slope school had a gust over 40 mph last hour…that’s up around Thompson and 120th in far NW Portland.

Good times…I know I’ll be waking up around 3am to see what happens when the precipitation arrives.  Or more likely 1:30am, 3:00am, 4:00am, etc…


Snow & Wind Update: Friday A.M.

December 17, 2010

I just looked at all the latest obs and model runs and see nothing different this morning.  All my thoughts are still the same as the previous post.  Since it’s a day off, I won’t spend the time to re-hash it all.  Anyone notice the 65 kts. at 2,000′ over PDX around 4am?  Never seen that.  And the 50 mph gusts forecast at the surface over Eastern Clark County?  Kind of surprised the NWS hasn’t hopped on that.  Maybe it won’t surface…we’ll see.

New models seem to be even a notch or two warmer than last night’s during the coldest of  the evaporational cooling around 4am Saturday.  If no one would have already mentioned snow, it barely would have crossed my mind.

Chief Meteorologist Mark Nelsen