YOUR Phone Can Help Improve OUR Forecasts!

August 23, 2016

Do you use an Android smartphone?  If so, would you consider helping out Pacific Northwest meteorologists by downloading a simple app?


It appears to be a strange request right?  But let me explain:

Cliff Mass (a professor at the University of Washington) has a project in which he’s trying to test the value of pressure observations from smartphones.  Their hypothesis is that a massive number of smartphone pressures could improve the initialization and forecasts of high-resolution numerical prediction models.  They want to use western Oregon/southwest Washington and the downstream regions (Gorge, Eastern Washington/Oregon) as a test area.  But they need to collect smartphone pressures.  To do so they have developed a powerful app for Android smartphones (uWx), which is available on the Google Play Store (   The web page for the new application is here:

In addition to collecting pressures, uWx provides wonderful forecasts, full resolution radar, and even accurate elevations for hiking.  So in exchange for providing that information you do get a nice little weather app as well.  Cliff tells me they really need observations from the Portland metro area and Columbia River Gorge.  So please help out if you can.

The app is not available for iOS (Apple) phones for now.

Cliff has done a blog posting about the project as well here:

Chief Meteorologist Mark Nelsen


The Great USA Eclipse Is Just 1 Year Away

August 21, 2016

Sunday 9pm…

We are less than 1 year away from the biggest astronomical event Oregon has seen in over a generation.  There will be a total solar eclipse in our state from 10:15-10:30am on August 21st, 2017.  That means Oregon will be cut in two by a ribbon of total darkness for 2 minutes.  The shadow of the moon will pass along a line from Depot Bay to near Ontario.  It will continue all the way into the SE USA by early afternoon.  This will be the first time since 1979 that we’ll see a total solar eclipse here.  And it’ll be quite awhile until we see another, although it’s interesting that one spot in the SE part of the country will see TWO eclipses within a span of 8 years since there will be one more eclipse back east in 2024.


Assuming skies are clear, the sun will look like this for about 2 minutes along the “line of totality”:


I think this web site is excellent, showing detailed maps of where you want to be for those two minutes:

And here is their map of the path.  Notice how narrow the “zone” will be: Stayton and Madras are perfect, but it’ll be useless to be in the Portland metro area or Bend, they are outside of the path and it will not be totally dark.


A real neat detailed pic from the same website (click for the best view):


Rumor says most or all hotels have been booked up for next year for quite awhile.  I’ve also heard much of remote Olallie Lake Resort is even booked!  There is “no room at the inn” apparently in Madras where thousands (or many tens of thousands or a hundred thousand) will be congregating for the two minute show.  Madras & Mitchell have the sunniest weather, on average, anywhere in the USA for this eclipse.  I’ve even heard a rumor that there could be an extra million or more people congregating on that strip in Oregon that morning.  Sounds like a traffic nightmare maybe?  It is interesting that the two big state parks under the totality with a good chance for sunshine can’t be booked until late November (9 month window).  I wonder how many people will be clicking like crazy on the Detroit Lake and Cove Palisades State Park website reservations on a cold and rainy November morning?

Anyway, read up the eclipse and make your plans!

Chief Meteorologist Mark Nelsen



Record High Temperatures

August 20, 2016

7am Saturday…

What a scorcher yesterday, as expected.  The highlights (thanks to Portland National Weather Service):


Click on these for the full image…

A few notes:

  1.  Friday was the first time we’ve reached 100 in late August (or September) since 1988!  It’s rare to get to 100 this late in the summer season as the sun angle gets lower and nights longer
  2. Astoria just experienced its hottest day in 55 years!  2nd hottest on record at Astoria airport since records began there in 1953.  It hit 100 in 1961 at that location.  Other locations in the Astoria climate record show temps warmer than 98…that was a cause of some self-induced Twitter drama on my part yesterday.
  3. Notice some spots in the north Willamette Valley and Clark County were slightly cooler today?  That was due to the east wind being a little “too strong”.  Slightly cooler air coming in from Eastern OR/WA.  That’s a really tough call in the forecast.  The areas that already had the NE wind Thursday were slightly cooler Friday. Interesting that some models picked up on it.  I think the WRF-GFS and ECMWF had hinted at the possibility.  A very fine nuance to the forecast, but interesting for geeks like me.
  4. 850mb temp over Salem hit +23.4 degrees yesterday afternoon, down just a degree from Thursday afternoon.  Yet some temps warmer in the valley/coast shows what the offshore wind flow can do.  Now image if we would have reached +27 degrees instead!  That’s what happened in mid-August 1977 when PDX hit 105 and some valley locations even warmer.

Here’s an interesting tidbit of hardcore PDX climate info, from Chris Callais over on both weather Facebook groups…yesterday appears to have seen the 2nd warmest noon temp we’ve seen at PDX:



We’ve got one more scorcher today and then Sunday looks wonderful with strong onshore flow.  Troutdale profiler at 6am shows (weaker) offshore flow still going:


It is slightly cooler in the lowest 1,500′.  Hmmm, might just be a 97-99 degree day instead.  That’s quite possible.  We’ll see.  Either way, one more hot day.  Stay cool!

The lengthening nights sure make a difference on our low temperatures this time of year.  I see some 50s in the outlying areas even under this hot airmass.  And PDX made it down into the lower 60s once the wind disappeared.  Yet in a few breezy spots in the hills (West Hills and Eola Hills near Salem) it only got down into the lower 70s.  Feels like Hawaii!

I see low clouds have returned to the coast so it will be MUCH cooler out there.  If you head out there (along with masses of others), it’ll be in the 60s and 70s…very nice.

Chief Meteorologist Mark Nelsen




Episode 40: The Heat is ON!

August 19, 2016

The podcast is back! Hot weather talk, plus an explanation of our 12 Day Trend. Plenty of laughs too and maybe even a little FOX12 gossip thrown in. Enjoy!

Northwest Weather Podcast


It is blazing hot in the Northwest this week, with temperatures soaring to the triple digits around the Portland metro area. On this episode, the guys break down our heatwave and let you know what to expect in the coming days, including some extreme fire danger and really toasty temps on the Oregon Coast.

They also take a close look at a massive wildfire burning out of control near Los Angeles and the devastating flooding in Louisiana.

Don’t forget, we love your weather questions! Track us down on Facebook and submit yours today.

View original post

A 100 Degree Day For Some, More Ahead

August 18, 2016

9:30pm Thursday…

What a scorcher today!  Even without east wind showing up much yet in the western Gorge (at least more than a light breeze) we saw high temperatures poke into the low 100s in parts of the northern Willamette Valley.

Here in Portland we officially made it to 99 at PDX, breaking the record of 96 set just last year on this date…


Check out the 100 Degree Club!


Even Astoria briefly got in on the act…a day early, with an 88 degree high.  That gives you an idea of what is possible tomorrow with a downslope easterly wind out there.  Forks, Washington made it to 96 as the easterlies arrived mid-afternoon.

Tonight rising pressure east of the Cascades means the east wind kicks in through the Gorge and maybe a little over the Cascades as well.  That means we will totally mix down the dry and hot air mass overhead.  I haven’t changed our forecast this evening since everything still appears on track for another record-breaking day tomorrow.  But there are a few minor tweaks…


  • Two more days of record-breaking hot weather ahead.
  • Areas AWAY from the Gorge will likely see another 1-3 degree rise in high temperatures.  That means high temps could be up around 104 degrees in a few spots like Hillsboro, Salem, or Battle Ground.
  • Areas that get the gusty east wind NEAR and IN the Gorge will actually be slightly cooler.  Troutdale likely stays below 100 degrees Friday.
  • The official high temperature forecast at PDX is problematic because too much wind could keep it below 100 again, or if the wind stays light enough it could be 104!  We went in the middle and have a 102 degree forecast.
  • Exact numbers don’t matter because it’s going to be baking hot tomorrow and the heat will begin earlier in the day.  Today it was 81 at noon in Portland. Tomorrow it’ll be 85-90 in those windy locations already at noon.


For the weather geeks out there, the 850mb temperature ended up just as forecast this afternoon over Salem.  It was 24.2 degrees.  The atmosphere overhead will be about the same tomorrow, but offshore flow really kicks in, thus the thoughts above in the highlights.

Looking further ahead, we DO get some quick cooling Sunday with a major marine push.  That should drop us a good 15 degrees, then another 5-10 degrees cooling Monday.  Much better!

That said, it appears there will be one more warmup the 2nd half of NEXT week.  This time temperatures will remain below 95 degrees, hopefully only up around 90.  No rain in sight!

Chief Meteorologist Mark Nelsen





The Big Heat Wave Begins

August 18, 2016

9:30am Thursday…

Hunker down (or find a cool river/lake to enjoy), it’s going to get really hot!  The NWS has a plethora of excessive heat warnings, advisories, and red flag warnings for most areas WEST of the Cascades from this afternoon through Saturday.


  • High temperatures the next 3 afternoons will be somewhere between 98-104 degrees in the lowlands of western Oregon and SW Washington.
  • We have never seen 3 consecutive 100 degree days (or even two) after the 15th of August, so if we get two or three that will be unprecedented.  That said, we’ve been quite close a few times in the past.
  • Breezy north wind today turns to a gusty easterly wind coming down off the Cascades and through the Gorge Friday.  That wind continues through Saturday morning, then it goes just about calm (hot!) Saturday afternoon.
  • Much more reasonable Sunday with highs at best around 90 degrees as a strong marine push begins
  • At the Oregon Coast, today will be much warmer with a few 80s possibly showing up, but FRIDAY is the scorcher with east wind pushing high temps well into the 90s for many towns.


Everything is on track this morning for a very late season heat wave.  Once we get past mid-August it’s very rare to hit 100 degrees.

A hot atmosphere has developed overhead.  850mb temps during the balloon sounding over Salem showed a +21.8 degrees, just what models have been forecasting.  They also say it’ll peak out around +24  to +25 for the next 3 afternoons with the trusty ECMWF forecasting those numbers.  That’s crazy hot, especially for 3 consecutive days with offshore flow.  I think the all-time highest August temp at 850mb is +27 during the 1977 heat wave.  It hit 105 in Portland that day.  So I’m pretty confident that we’ll get at least one day above 100 and we might possibly do all 3.  This is what we’re forecasting right now for highs at PDX and the records we should break:


Friday or Saturday will likely be hottest since 1) Friday has the best offshore flow and we start “pre-warmed” from today, but not so crazy windy that it holds the temp down a few degrees AT Portland airport and, 2) Saturday we start with offshore flow and then the wind goes calm in the afternoon, yet we don’t start to get a cooling northwest wind up the Columbia River.  Those are just about perfect heating conditions for PDX.

Offshore flow has already begun this morning, even at the surface there is a very light easterly gradient through the Gorge.  In the Cascades an easterly wind has begun with gusts to 30 mph at Three Corner Rock north of Bonneville and 30-40 mph gusts at the top of Upper Bowl Chair at Skibowl.

I expect temps to slowly rise through noon, then really take off.  During a heat wave in 2008 the temperature rose from 82 to 102 from noon to 5pm, proving that the warm air above can surface quickly!

As mentioned earlier, hitting 100 this late in the season is tough to do…in fact the last time we got above 100 in the 2nd half of August (or early September) was way back on September 2nd, 1988!  I remember shoveling corn and carrot slop on that day working at National Frozen Foods in Chehalis (my job for 6 summers in high school and college) inside the plant.  Geez it was hot!  Obviously no air conditioning in a place like that.  There’s nothing like warm carrot “goo” at 100 degrees.  Yet, it did allow me to get out of college almost debt free!


Stay cool…

Chief Meteorologist Mark Nelsen


Heat Wave Update: Hottest of Summer & 90s at Coast

August 16, 2016

9pm Tuesday…

It’s gonna get hot!  Okay, that’s a bit of a cliché but it’s true, I see a real scorcher coming up the 2nd half of the week.


  • Thursday-Saturday highs will be somewhere between 95-103 in the Willamette Valley and Portland Metro area.  That’ll be the hottest 3 day stretch of summer
  • Strong east wind arrives Friday not only in the Gorge but also west slopes of the Cascades and down into the valleys.  That means extreme fire danger and maybe some downed corn stalks too!
  • Fire danger will be extremely high west of the Cascades Friday and Saturday with the dry east wind.  Any fire that starts could spread very quickly.  Historically the largest fires west of the Cascades have spread in just these conditions here in western Oregon.
  • Friday may be the warmest (hottest) day in almost two years at the Oregon Coast.  For one day (Friday) and possibly part of Saturday, east wind will make it to the Oregon Coast.  Assuming that occurs, high temperatures will be in the 90s (yes, 90s!) in many spots out there.

Things have changed a bit in the last 36 hours.  First, a hot upper-level ridge is going to develop just to our west Thursday-Saturday, in the offshore waters of the Pacific Northwest.  No change there, but now models show a small but potent disturbance dropping down the east side of the ridge, bringing a taste of fall into Montana.  The next question is “what does that have to do with us?”.  That cool air is high pressure, so now all models are in agreement we get a strong easterly flow over the Cascades and through the Gorge.   Here’s the Friday 5am surface pressure map from the ECMWF.  The yellow line is the lowest pressure, air will flow toward that “thermal trough” as we call it.  Notice it’s on or even off the coastline at that time = east wind all the way to the beaches.


That easterly flow is the “icing on the cake” for a “perfect” heat wave.  850mb (5,000′) temperatures are forecast to remain near +22 to +24 (celsius) from Thursday through Sunday morning.  Such hot temperatures would typically push us well up into the 90s or even about 100 degrees this time of year.  Add in the extra heating as the dry wind races downhill off the Cascades and you can add another 3-5 degrees.  As a result there is no reason we can’t get to 100 degrees or above at some point between Thursday/Friday/Saturday.


On Thursday the offshore flow is just getting going in the afternoon, so I kept the high temperature down to “only” 98 degrees.  It’s sure possible we hit 100 degrees though.  Friday is the trickier forecast because we may have so much east wind blow here in the metro area that it might keep our high temperature “down” a few degrees.  As a result I’ve gone with a 95 for PDX.

Saturday (at this point) looks like the hottest day to me; hot airmass in place, easterly wind to start then it goes mainly calm in the afternoon, and full sunshine.  I put a 100 for Portland that day due to those factors.  Sunday we lose the offshore flow so even though it’ll be hot it should be well below 100 degrees.

Hitting 100 past August 15th is tough to do in Portland due to decreasing sun angle and about 2 hours less daylight than late June.  But check out 3 past episodes including Portland high temps and 850mb temp measured over Salem.  Notice how the atmosphere was overhead in 1977!

August 16th/17th 1977

102 deg / 850mb temp +24.6
105 deg / 850mb temp +27.0

August 14/15th 2008

102 / +24.6
100 / +26.6

August 18th/19th 2015

96 / +23.4
97 / 20.6

The coast is always a very tough forecast during hot weather episodes but this is what I’m thinking right now:


Saturday is the tough forecast day as we get a flow reversal and its southwesterly surge of fog and cool air pushing up the coast.  Friday will likely be the hottest day we’ve seen at most locations along the Coast since September 2014.  That month we saw a day with high temperatures in the low-mid 90s out there!

This whole episode is a bit extreme, but definitely not something “unprecedented” or unheard of in mid-August.  It just doesn’t happen that often.  In fact there have only been 5 days in Portland’s history where the temperature has made it to 100 degrees from the 18th of August through early September.  Interesting that 4 of those happened in 1986, 87, & 88 isn’t it?

Chief Meteorologist Mark Nelsen



Get every new post delivered to your Inbox.

Join 420 other followers