Sunday…A Spectacular Day!

October 19, 2014

Bright sunshine and temperatures well into the 70s on October 19th; no wonder I saw a lot of people outside today as I found the end of the Springwater Trail!  At 3pm the temperature is 74 at PDX, likely headed for a high of 75-77.  The record for the day is 78 so we probably won’t hit it.  Still, it was great to bicycle outside in the sunshine as if it was summer.  At least this will make winter come a bit faster mentally.

As for the Springwater Trail, that’s the paved bike/walk/hike path that goes 22 miles from Downtown Portland to Boring.  The last 2 miles or so were just paved withing the last couple of years and were especially smooth.  My son and I rode from Gresham out to Boring this afternoon.  Officially the trail ends there…for now, and the trail becomes the Cazadero Trail at that point. The next 3 miles of the old railroad bed are an improved gravel surface which was really easy on mountain bikes, actually a bit better than my driveway.  IMG_0593  It heads downhill along the north fork of Deep Creek.  You only pass 2 or 3 homes otherwise you are in the woods.  At the 3 mile mark the trail suddenly ends at a dropoff.  There used to be a railroad trestle at that location; all that’s left is the concrete abutment.IMG_0592  At this point you are only 1/4 mile or so from Hwy. 224 at Barton, just above Barton Park.   Obviously it’s not going to be cheap to get the trail down to the highway, but from what I read online, the plan is to finish the trail to Estacada or a little beyond to one of those dams.  For now you have to turn around and go back uphill to Boring, which was only about 300′ up in elevation.  It’s also interesting that when bicycling the 6 miles from Gresham to Boring, you really don’t notice that you’re going uphill, but you can sure feel it coming back…significantly faster.  Reminds me of my big bicycle ride last year from Elgin to Joseph.  In 35 miles you climb around 2,700′, yet it’s just barely noticeable…mostly you just feel like you’re getting a little lazy and pudgy.

I hope you all were able to get outside and enjoy the beautiful weather because the chance of us hitting 70 degrees again is pretty slim.  Take a look at the 12z ECMWF meteogram…lots of wet and much cooler as temperatures really fall off over the next 10 days.  KPDX_2014101912_dx_240

Chief Meteorologist Mark Nelsen


A Record Long Growing Season; At Least in One Spot

October 16, 2014

Have you noticed what is missing this October?  Frost!  Not here in the metro area, but elsewhere.  Only the higher parts of Central and Eastern Oregon have seen frost so far.  It hasn’t even been close west of the Cascades.  Considering we have lots more above average nights in our 7 Day Forecast, that means many areas that should have had a frost by now are seeing an unusually long growing season this year.

Tim Dearden from Trout Lake WA (north of Hood River) says there has still been no frost since April 28th at that ~2,000′ location.  He looked up the records and found that Trout Lake Ranger Station is already 15+ days ahead of its longest growing season ever!  He too noticed that nights have been much warmer than normal during the summer and early fall.  If you’ve ever been to Trout Lake, troutlake it should be obvious to you that there is no urban heat island in that location!

Tim took the numbers and plotted out the growing season length over the past 90 years.

Plot

Isn’t that interesting?  It appears the growing season IN THAT LOCATION is averaging 2-4 weeks longer than 100 years ago. I don’t have the time to research it, but I’m wondering if it’s mainly the fall dates that are changing the past 30 years at least and not the spring dates.  I was thinking it might be related to summer warmth that seems to be spreading into early fall more often.

I’d love to see how the numbers look for a few other rural locations, like maybe Corvallis, Aurora, or Hillsboro (still mainly rural at airport).  Someone get to work on some spreadsheets!


A Windy Day, And A Tornado That Never Was

October 15, 2014

The gusty southerly wind showed up as expected this morning, with peak gusts in the 25-35 mph range for most of us.  PDX hit 35 mph.  That of course prompted some scattered power outages, but those were pretty much gone by early afternoon.

Around 4pm we got an email from a viewer that thought a tornado may have gone through the part of Woodburn just west of the Outlet Stores.  So we sent a reporter down to check it out.  I assumed it probably wasn’t much, but you never know.  In the past I’ve found that unless several viewers call/email/tweet from a populated area like that, there’s a good chance that it wasn’t a tornado.  So I was surprised when I read two tweets (from other news organizations) that said there was a small tornado in Woodburn.  I said “What?”, fearing I had fallen woefully behind in the information business.  I checked the “pre-2010″ channels of National Weather Service information, which involves checking Public Weather Statements and Storm Reports…Nothing.  So then I went to the “pre-2000″ level…I called the NWS.  Of course they said “What?” too, noting they sent a team down to investigate but as of that time (5pm), there was no tornado.

Sure enough, damage pictures came in from our reporter Laura Rillos…

Woodburn Tornado 3 Woodburn Tornado 1

and showed what the NWS told us in a Tweet around 6pm…”Storm survey concludes down tree limbs on Butteville Rd (west of Woodburn Outlet Mall) was from 30-40mph straight line winds & NOT a tornado

It was just a heavy shower that sent out a strong straight-line wind.  A lot of drama for that, but it sure made two hours of TV pass quickly!

Chief Meteorologist Mark Nelsen


Spaghetti Plots…Storm Approaching Hawaii

October 14, 2014

Tropical Storm Ana is revving up and should become a hurricane within 24 hours.  This storm is forecast to end up somewhere over or quite close to the main Hawaiian Islands.  If a landfall actually happens, as far as I’m aware it will be unprecedented in historical times.  Here is a map showing all the storms that have passed within 75 miles of the main island chain…not as many as you would think:

hawaii

Of course there is always error, especially 4 days out.  The official CPHC forecast looks like this right now:

MarkTropical_HurricanePacific MarkTropical_HurricanePacific2

But you might find this more interesting…a loop showing all the different model forecasts for where the center of the storm will go.  Each line is one model.

Interesting stuff eh?  Shows you why the forecast track can be so uncertain and also why it’s so important to not focus on a specific track in the middle of the “forecast cone”.  And you can also see why we call these types of charts “Spaghetti Plots”!

So as of right now it might not be a big deal, or it might be a huge storm.  For it to be a big storm, the center has to hit one of those little dots of land!

Chief Meteorologist Mark Nelsen


How Windy Tomorrow? Not a Storm, But Windy

October 14, 2014

We stayed mainly dry in the metro area today since the main rain band with a cold front has been just to our south.  We figured it would be right over us instead.  Nice way to bust a forecast though!

You may have heard rumblings of strong wind coming tonight or Wednesday.  Here’s the latest:

  • A windstorm is not on the way
  • But gusty southerly wind will develop across the western valleys of Oregon/SW Washington and the coastline late tonight and then die down after mid-morning tomorrow
  • Peak gusts 30-35 mph are likely for most of us.  About 5-10 mph stronger than last night’s gusts.
  • 40-45 mph at the Coast
  • This is strong enough for a few limbs to fall since most leaves are still on the trees, of course there will be a few scattered outages.

The NWS issued a Wind Advisory earlier this afternoon for peak wind gusts around 40 mph in the central/north Willamette Valley tomorrow morning.  I think that’s a bit much and 40 mph gusts are a bit high.  I bet PDX ends up with a peak gust 30-35 mph at best.  That said, 30-35 mph gusts in mid October will easily bring down some branches…and lots of leaves!  That means some scattered power outages are possible again like this morning.

Where is the wind coming from?  A surface low or open wave will scoot quickly north along the coastline later tonight and tomorrow morning, giving us the rush of air behind it from the south.  Models are in some disagreement on how much wind we get (lowering my confidence that anything interesting will even happen!).  The NAM has no strong wind at all, the HRRR shows no gusts over 30 mph (or even less) in the Valley:

HRRR_WindGusts

The ECMWF gives a little more energy to the wave in the afternoon, which means no closed low and not much wind in the morning.  The WRF-GFS is alone showing wind gusts maybe 35-40 mph late tonight and early tomorrow:

wgsfc.27.0000

Our RPM model looks like this:

RPM_12KM_Wind_NWOR

That would imply gusts close to 40 mph, but our model almost always is too high…note the text output

web_RPM_18z_Text_PDX_4km

With most wind events you can assume this text output is 5-10 mph too high on gusts, so this tells me not much is going to happen tomorrow other than the effects I noted above.

Chief Meteorologist Mark Nelsen


Last Warm & Sunny Day For Awhile

October 13, 2014

5:00pm Monday…

What a spectacular Monday afternoon!  Temperatures have jumped into the mid 70s in the metro area (where the south wind has surfaced).  That’s a good 10 degrees above average and pretty good considering some spots started foggy and chilly.

It’s not really a “storm”…more of a juicy cold front sitting just offshore with the first light rain just moving onto the coastline at this hour.  The front will gradually move inland tonight, giving us a rainy night with some southerly breeze at time.  It doesn’t appear to be a heavy rain producer, but a nice soaking again.  The HRRR model is giving most areas west of the Cascades in the valleys less than 1/2″ rainfall through sunrise.

HRRR_RainTotal

Beyond that, the front stalls over and west of the Cascades tomorrow, which means frequent showers along with a cooler airmass.  I noticed the Lifted Index is below zero along with some CAPE tomorrow afternoon, so I threw a thunderstorm chance into the forecast.  More showers are likely Wednesday, especially early in the day.

Not so much action Thursday through Sunday with a weak system swinging through Friday night and Saturday morning…timing depends on which model you look at.

On Sunday we get a stronger upper-level high developing just to our east, putting us into a warm (and eventually moist) southwest flow in the upper atmosphere.  As a result I don’t see a setup in the next 7-10 days that would bring anything other than a brief dusting to the higher parts of Timberline and Meadows.

Big picture shows some sort of troughing in the eastern Pacific for the next few weeks, in fact last night’s run of the ECMWF out to 32 days showed off/on wet for quite awhile!

500za_week1_bg_NA

500za_week2_bg_NA

500za_week3_bg_NA

500za_week4_bg_NA


Looking Wet Next Week!

October 9, 2014

3pm Thursday…

A quick addition to yesterday’s post.  Confidence is still very high that a few days of soaking rain start Tuesday…or maybe as early as late Monday evening.  Here’s a nice graphic from the folks at WeatherBell, a great weather data subscription service…worth every penny!  It’s from the morning ECMWF (European) model, widely acknowledged as the best we’ve got on the planet right now.  It’s not always right, but is consistently better than the American models.

ecmwf_rainensemble

The blue bars across the bottom represent rainfall accumulation as we proceed through the next 10 days at PDX.  The green bars show the ENSEMBLE AVERAGE of the same thing.  That’s 51 versions of the same model run averaged together.  You get the idea…the rain gradually adds up after Tuesday.  You can see in two spots the “operational run (blue)” goes a bit higher but ends up almost exactly the same as the ensemble 10 days from now.

The upper part of the chart is pretty isn’t it?  Each row is ONE of the ensembles.  They are all stacked on top of each other.  I often don’t even look at this one except for situations where I’m wondering whether we will get rain at all at a certain time.  OR, there is snowfall version of this chart and you can see how many of the ensembles are generating snow in our area.

As I’m making my forecast this afternoon and I see this, it screams…WET!  The details have been changing, but the models have been consistently forecasting the big move towards our first real wet pattern since spring.  Turn off the sprinklers…

Chief Meteorologist Mark Nelsen


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