Fire Season 2015: It Could Have Been Much Worse!

September 24, 2015

One month ago the Pacific Northwest fire situation was bleak with almost one million acres burning in Oregon and Washington forests and range lands.  But today, what few fires left are just smoldering and no significant acreage has burned in many days.

We’ve known since mid-spring we could be facing a very bad fire season…consider the setup for the “PERFECT FIRE SEASON”

  1. Moderate to severe drought across much of the region has continued from one to several years
  2. The worst snowpack in MANY decades last winter/spring for much of the region’s mountains.
  3. Temperatures were warmer than normal from winter through early summer; causing what little snowpack remained to melt quickly.  Soils dried out quickly as well.
  4. June was the warmest on record for much of the Pacific Northwest, with a severe heatwave at the end of the month.  Remember the 110+ temps in the Columbia Basin?

By late June, during that big heatwave that went on for about two weeks, I figured it was going to be REALLY BAD in July and August.  But July came and went without any big blowup of fires.  As of late July, acreage burned across the Pacific Northwest was below normal!

What happened?  We were blessed, or lucky, or whatever you want to call it, by two big changes from previous fire season

1. Far less lightning this summer

Take a look at the past 8 years worth of lightning strikes in Oregon and Washington:


So far, less than half what we saw in 2014, and only 25% of the action two summers ago!  And according to the BLM the largest “event” consisted of just 6,400 strikes.  The past two summers we saw peak events in the 21,000 to 38,000 strike range.

2. Cool with rain late August/September

What a change from warmer than normal to a bit cooler than normal in September!  Quite a refreshing month.  We’ve gone through 4 warm/hot Septembers and now it’s payback time.  Note we’ve seen the fewest 80 degree days this month since 2010.


There hasn’t been a ton of rain, but several showery periods east of the Cascades along with snow at mid-month above about 6,000′ in Eastern Oregon has done the trick!

This is how the acreage burned looked as we went through the fire season (thanks to the BLM folks, click for a larger view):


Note the below normal numbers, then the huge jump in August, then leveling out in September.  We’re pretty much done with fire season now.  Of course we can still get fires in October, but not the huge ones we see in the summer.

One more interesting chart, showing the acres burned per week:


You see the weekly numbers jump in mid-late August, then a big crash.  I don’t understand why there is a jump of 150,000 acres only a week or two ago because I don’t remember any big new fires during that period.

In the end, Fire Season 2015 will end up with above normal acreage burned…definitely a big fire season with lots of homes burned.  But almost all the action happened during a one month period in August.  I think it could have been far worse!

Chief Meteorologist Mark Nelsen

A Pretty Bad Climate Model Forecast

September 23, 2015

I just saw this on WeatherBell’s site this morning.  Back in July the CFS model was showing the hot summer continuing into a very warm September.  Considering fires were just getting going and we were so dry, this looked really bad with ridging continuing:


But look at what has actually happened:


The exact opposite.  A spectacular failure in the 2 month time frame eh?

On the positive side, it brought the fire season to a screeching halt; there are no large fires actively burning in our state.  The 3 “official” large fires are just smoldering and I see Umatilla National Forest has even started the regular fall prescribed burning.  Plus, we were set up for a really bad September west of the Cascades when the unusually dry conditions could have caused havoc with the seasonal arrival of hot easterly wind.  That didn’t happen and now the ground in the woods outside my home is somewhat moist.  Fire season is pretty much over.

Of course the other benefit was a very early start to summer meant an early end too.  Labor Day really was the end of the hot stuff, minus those two days mid-month in the 90s.

For the next two months, here is what the CFS shows:



Supposedly warmer than normal through November…we’ll see.

Chief Meteorologist Mark Nelsen

ECMWF Monthly Run

September 21, 2015

You know the drill; hardcore weather geeks only beyond this point on this post…

Not TOO much different than what it was seeing a week ago.  Hints that the upper-level trough that has been nearby much of this month will shift a bit farther west around the 2nd week of October.  Not much change in the next two weeks though.  Looks like our cooler than normal September will continue the next 10 days.








New info from here on out…looks like ensemble mean for precipitation (through the 18th of October) is around 2″, about 1″ on the control run…so a bit drier than normal and no obvious sign the wet season is about to begin.

Chief Meteorologist Mark Nelsen

Strong El Nino This Winter: What It Means In The Lowlands

September 17, 2015

Let’s talk about El Nino again.  I’ve already covered the basics in a post earlier this week.  I suggest you read the first few paragraphs of that posting first

First, we tend to see a changed jet stream during El Nino cool seasons.  Typically the Pacific jet stream flows generally west to east and runs into the northern half of the USA West Coast.  Thus the heaviest winter rains tend to fall in the Pacific Northwest, as opposed to California:


But during most El Nino winters we see the southerly part of the jet stream suppressed farther south, partly due to a stronger area of low pressure in the eastern Pacific.  Actually the subtropical jet is pushed farther north than normal, heading into California.  At the same time we tend to see more episodes of upper-level high pressure over the western part of Canada.  This shunts arctic air farther east than normal, giving the Northern Plains a warmer than normal winter.  Meanwhile that wet (and warm) westerly jet running into California gives them a wetter than normal winter.



Notice the Pacific Northwest is a mix of weather.  The northern part is strongly influenced by the upper-level high, the southern part (southern Oregon) often gets in on the edge of the California moisture action.  As a result, southern Oregon ski areas and basins receive normal or even above normal precipitation.

It’s important to point out that though many El Nino winters follow this pattern, sometimes they don’t .  No guarantees!  It has also been noted that in the very strong El Ninos, the heavier precipitation appears to make it farther north.  Both 1982-83 and 1997-98 (strongest since 1950) both featured near or above normal rainfall even up here in Portland.   1983


Compare that to 2009-2010, the traditional El Nino signature…


What about extreme cold during this winters?  A bit of a mixed bag because even in a mild winter it only takes one 4 day arctic blast to trash your plants.  4 out of 15 Strong/Moderate El Nino’s had a significant outbreak of “arctic” air.  If you take just the STRONG events, only one in the past 40 years has given us a days-long arctic blast event.  That was 2009-2010.  We hit 12 that year!  So the likelihood of a long arctic blast is quite a bit lower than normal, occurring in only 27% of moderate/strong years.


Of course what everyone really wants to know is…will it snow at MY house this winter???

A misconception to get rid of is that a warmer/drier winter means no snow in the lowlands.  Not true at all. El Nino does NOT mean NO SNOW.  Check out the last 6 moderate/strong El Nino winters:


We saw decent snow storms in January 2007, January 1998, & February 1995.  And who can forget the fiasco in late December 2009…the surprise (crappy forecast) snow event that gave us the worst evening commute in many years!  There is one common theme in each of these events; they all lasted just a short time, then the mild winter resumed.  I distinctly remember shoveling feet of drifted snow (Corbett) in January 1998 under a “hot” 50 degree sun once the east wind stopped.

To summarize…

It’s unlikely we have a snowy/cold winter ahead, but it’s quite possible we get some sort of freezing rain or snow event at least once during the upcoming winter.

One more point…one of the most hated parts of winter for part of the metro area is the cold east wind.  The Columbia River Gorge produces what we call a “gap wind” when high pressure east of the Cascades sends air rushing through the sea-level gap through the mountains.  The east side metro area near and south of the Columbia River is fully exposed to the wrath of this wind.  It begins to appear in late October and reaches a peak from November through February.  Then the wind disappears in early March as the seasonal westerlies begin.

Does El Nino mean more or less east wind?  Based on my experience, it’s generally a case of MORE east wind.  That’s because during El Nino years, we have a split or blocked jet stream more often, leading to more time under surface high pressure.  And much of the time that’s centered east of the Cascades.  Notice the most easterly wind the past few years was during our last El Nino event in 2009-2010.



  1. Most likely we have a generally milder and drier winter than normal.  Or at least milder temps with normal rainfall if we get lucky.
  2. Long periods of cold/snow are very unlikely
  3. We could easily see a snow or ice storm at some point
  4. Widespread regional flooding is unlikely this winter
  5. Expect a bit more east wind than normal this year again

Here is a chart showing some of the data I used while researching past events:


Chief Meteorologist Mark Nelsen

Wettest Day Since Spring Break!

September 17, 2015

The heavy shower that moved over PDX between 2-3pm dumped almost a quarter inch of rain.  That combined with earlier showers puts us up to .53″ for the day so far.  That’s the most rain we’ve seen in a calendar day since March 23rd!  It’s about time.  It’s very unusual to not see a .50″ day at some point in April, May, or June…evidence of how extremely weird late spring and early summer was.


Chief Meteorologist Mark Nelsen

Cold Core Funnel Near Albany

September 17, 2015

Viewer Jeff Buccello sent us this video of a funnel cloud north of Albany around noon on Thursday.  Remember to always look for rotation.

Seems like about 50% of cool/showery days we get a view pic/video of a funnel cloud.  Definitely not rare, but always neat to see!

Chief Meteorologist Mark Nelsen

12:30pm: Forecast Bust In Progress

September 16, 2015

I love it when (once in a great while) my forecast goes wrong like this!  A weak system off the southern Oregon coast is moving more slowly than anticipated which means 3 things at the noon hour:

  1. Showers have only made it into SW Oregon so far.  Radar is pretty much dry all across NW Oregon and SW Washington
  2. Most of the afternoon should be dry for most of us.  A few sprinkles show up around dinnertime or sunset, but it’s quite possible it won’t rain until after sunset.
  3. Temperatures are warmer than expected…around 70 degrees already with a light offshore wind (easterly).

Here’s the latest radar loop.


Now get outside and enjoy the nice day!

Chief Meteorologist Mark Nelsen


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