Almost Here!

November 21, 2009

All of us are watching that low approaching the Coast tonight.  I was distracted by about 2 hours of Netflix viewing with the family, but they are in bed and now it’s time for the weather party!   Too many people on my road are downloading movies, or something else, because my connection is REALLY slow.  Which means plenty of time to analyze each image of the IR loop. 

Looks like at 11pm the low is just about straight west of Astoria, maybe just about on top of Buoy 46089?  Notice the strong wind there suddenly went light WSW.  If it had gone south of that point the wind would have clocked around to the north and then northwest.  If it was very far north, the strong south wind would have gone gusty SW.  Pressure is 988 mb at 11pm there.  Pressure was forecast to be 987mb at 11pm, but the low was supposed to be west of Hoquiam on the WRF-GFS.  WRF-NAM had it slightly farther north than it is now and a bit weaker.   Satellite presentation (comma shape, vapor darkening, and cold air behind) are very nice.   How about the 8.2 millibar drop in pressure at PDX in the last 3 hours?  That’s very impressive.

So I still think we’re on for a quick burst of wind maybe 3 hours from now in the Metro area.  For the sake of verification tomorrow, I’ll say S-SW 30 with gusts 45-55 mph at the airports.  This will be enough to wake most people up and give us plenty of power outages.  It’s not a big windstorm forecast, but since the depth of the low is tracking well with the models, I don’t see a good reason to get crazy.  We haven’t gone above 49 mph at PDX in two years so this could be a big one.

I’ll be hanging out in the comment section until bedtime.

Chief Meteorologist Mark Nelsen


Keeping a Close Watch

November 20, 2009

Oh, that doesn’t look so good in miniature form.  Click on the image to see the 45 hour sea level pressure map from the UW’s WRF-GFS.  It shows a relatively deep low moving from about Tillamook to Yakima late Saturday night.  It’s a wave on the trailing end of  tomorrow’s very wet cold front.  On this model it deepens to about 989 mb.  This setup HAS, in the past, produced a windstorm in the north Willamette Valley.  It’s been a very fast event too.  A sudden surge of SW wind, maybe 2-3 hours maximum, then that’s it.  Wolf Read has the most amazing collection of data for Pacific Northwest windstorms.  He has a good writeup on the January 1990 storms.  Keep in mind there were a series of storms and the one similar to what I am thinking is the night of January 7th-8th 1990.  That produced gusts 60-70 mph here in the Portland Metro area and damaging westerly wind gusts in the Gorge.

Now that’s one model…the 18z NAM and our 12z/18z RPM both show the low either over us or slightly to the south.  The NAM has it passing over Salem, which is a good windstorm for the south Valley but nothing here.

So this could be nothing for us here in the Metro area or a great quick windstorm coming up tomorrow night.  Ahhh, the anticipation of the 00z models! 

11pm Update:

00z models seem to have come together a little bit, but not enough to say with confidence that we do OR do not have a strong wind event on the way.  Our RPM model and the NAM are the southern models with a track from Tillamook to Yakima.  The NAM is pretty much right over Portland and weakening as it moves by; not good for a strong southerly wind here.  The RPM only gives 8 millibars EUG to PDX.  Gusts 40-50 at best with that.  The 00z GFS is the stronger one and has the track farther north, maybe AST to North Central Washington.  This one gives us 10-16 millibars gradient from Eugene to Olympia.  That’s more significant, especially the WRF-GFS version.

So this means we are still up in the air and must say “can’t wait for the 12z models!”.  Hopefully they’ll have more agreement.  My gut feeling is that this may just be a non-event since we didnt’ see any dramatic strengthening in the 00z runs…but we’ll see.

Chief Meteorologist Mark Nelsen

Snow and Weather Geekery

November 19, 2009

As of yesterday Gov’t Camp has now reached the average November snowfall total of 32″.  And I think it’ll pick up 12-18″ more by midday Sunday.  That’ll put it near the upper end of November totals in the last 10 years.  A strongly orographic flow (straight from the west) late Friday through early Sunday should squeeze a lot of snow out of Saturday’s juicy system.  It’s a great start to the ski season for sure.  Just in time, the weather really slows down next week as well.  I see the 00z GFS is definitely looking a bit more ridge-ish beginning Monday.  The ECMWF is still far more splitty “El Nino-ish”.  Either one will give us Thanksgiving week to relax and focus on families instead of crazy weather.


And this just in from Steve Pierce…


I DO plan to attend, maybe with the little Nelsens too.  I will NOT be dressed up nice either!

Don’t forget the 3rd Annual Ch.12 Weather Blog Pizza Party & Oregon AMS monthly meeting is this Saturday from 2-4pm at Stark Street Pizza in Portland! Don’t forget to bring your favorite weather photo (digital or on paper) to share with the group. We are also going to raffle off a $250 Maximum Wind Anemometer along with other items! If you have something to add to the raffle, please bring it with you. You will not want to miss this event! It should be a packed house! Children, spouses, significant others are also welcome! By the way, the pizza is great!

 For complete details and directions, please see:

Here’s a picture from last year:

Active, but Not Wild Weather

November 18, 2009

Just for fun and a look at the “behind the scenes”…here’s the note I just sent out to the newsroom. This is how we let them know what’s going on:

COASTAL WIND: It has not been impressive so far. The main wind has been on the Washington Coast. Peak gusts on the Oregon Coast have only been 40-50 mph with a spot or two slightly higher…a bit of yawner for them. I still think it’ll pick up some overnight, but gusts will stay below 70 mph. There will be a lull tomorrow morning, then another surge of wind tomorrow midday or so with gusts of 60-70 mph. Definitely not a major storm, but a windy period out there.

COASTAL RAIN: It has been heavy in SW Washington, but not so much in the North Coast Range. As of now no rivers are forecast to flood in N.W. Oregon.

WESTERN VALLEYS (INCLUDING PORTLAND METRO): It’s breezy and we’ve had some rain, but less than 1” expected in the next 2-3 days. Wind gusts should stay below 35 mph.

I’ll have a bit more of a meteorological angle on things coming up a bit later…

Okay, let’s try it again.  I posted, but then apparently it had logged me out…really annoying and a lost post.  Looks like a lull in the wind late tonight through tomorrow morning, then the 2nd low is heading for Vancouver Island by late tomorrow afternoon.  Wind gusts should be a bit higher at the Coast.

That 00z WRF-GFS did catch my attention with a 3rd little low moving onto the Washington Coast on Friday.  If it is deeper on later runs it could give us some good wind.  But that model is the only one that has shown it so far.

Out of time…everyone is heading home and I am too.

Chief Metorologist Mark Nelsen


A Quiet Evening

November 17, 2009

Not much happening weatherwise this evening.  Yes, the startling picture of me wearing white socks with the suit has been making the Twitter rounds; but that’s just because I forgot to bring black socks to change into.  It may have cost some public humilitation, but I saved the $5 to spend on Christmas gifts for the kids…or something like that.

There are some thunderstorms moving onto the coastline with a cold trough, but I haven’t seen any lightning strikes in the last 1/2 hour.

We’ve got two more deep lows developing well offshore the next 2 days.  The latest model runs keep us mainly dry from Portland south the next 2 days as the main frontal band hangs along the Coast and up into Washington.  We get a tight south-north pressure gradient with both lows.  This should be a good 24+ hours of gusts 50+ at the Coast and 30-40 mph here in the Valleys.

There are hints of some sort of ridging beyond next Monday, but models seem to be all over the place.

Chief Meteorologist Mark Nelsen

Last Storm Update

November 17, 2009

Okay, this is REALLY the last update. I’m home now and it looks like cold front has moved through; the wind is dying down quickly.

I think peak gusts were all 38-48 mph in the area (most around 40 mph) except for a lonesome gust in the 50s somewhere in Clark County. Not exactly a windstorm, but a nice warmup for something later this winter???

Chief Meteorologist Mark Nelsen

Evening Wind Update

November 16, 2009

Okay, last one for today.  Strong upper-level wind is surfacing nicely during the last hour central/western Metro area.  The stubborn easterly flow out of the Gorge just won’t give in on the far eastside near the Columbia River.

The main reason I believe we are getting a lot of mixing down is the dewpoints in the 30s and temps in the 60s!  That’s pretty dry air considering we are just south & east of a warm conveyor belt of heavy rain moving into the north Coast Range and western Washington.  Also notice the pathetic 7 millibars EUG-OLM gradient.  That only gives peak gusts 25-30 mph at face value.

Strongest wind should be in the next few hours as the cold front approaches.  Hope we don’t get any surprise 50-60 mph gusts!

Oh, and it looks really wet the rest of the week.  Many inches of rain in the mountains and an inch or two the next few days in the lowlands…yuck.

Chief Meteorologist Mark Nelsen