Oregon AMS Winter Weather Conference THIS SATURDAY

October 20, 2015

Hey folks, that once-a-year weather “Fall-tacular” is back! (that was a Phil Hendrie reference for you fans!)

It’s the 23rd Annual Winter Weather Forecast Conference – This Saturday 10/24 @ OMSI in Portland.  10:00 A.M.


Meteorologists from across the Pacific Northwest will once again give their prognostications for the upcoming winter.  Will the current El Nino offer up warm and drier than normal or warmer and wet conditions this coming winter? What about the Cascade mountain snow pack?

NEW — Dr. Wolf Read will have a special presentation on the rare August 29th 2015 windstorm that raked the Pacific Northwest!

NEW — Dave Tragethon (Mt. Hood Meadows) will talk ski slope weather for the upcoming winter! Come hear all the details.

One lucky person will walk away with a $300 Davis home weather station that will be raffled off as well.  It’s currently sitting in my garage at home…unopened of course.

Where: Oregon Museum of Science and Industry (OMSI), main auditorium, 1945 S.E. Water Ave. in Portland.
Driving directions to OMSI: http://tinyurl.com/6rrz8em.

Meeting and parking cost: This meeting is free and open to all ages of the general public. Free parking in all OMSI parking lots.

Agenda: Meteorologists from across the Pacific Northwest will once again give their weather prognostications for the upcoming winter.

I’ll be giving my usual wrap-up of the past weather year.  Believe it or not, there is PLENTY to talk about (65 PowerPoint slides so far!).  That’s due to the unusually warm weather regime we are in.

One change as we head forward, this is morphing into a “Winter Weather” vs. “Winter Forecast” meeting.  There doesn’t seem to be as much interest in forecasting as in the past, so we’ve added some additional folks to beef things up.

I’ll be selling raffle tickets for the Davis Vantage Vue weather station in the back otherwise…hope to see lots of you there!


Chief Meteorologist Mark Nelsen

A Dry October…So Far

October 18, 2015

10pm Sunday…

I just noticed we’ve still only had .43″ rain at PDX since the beginning of the month


Of course it’s only the 18th and anyone that has lived here very long knows the wet season can kick in quickly in the last week or so of October.  As a result it would be premature to say it’s going to be a real dry October.  That said, I don’t see much rain between now and next Sunday.  That means less than 1″ in the bucket with just the last week of the month to go.  It could end up being like 2011 or 2013.

This shouldn’t be a real surprise in a strong El Nino fall.  I used the great NCDC anomaly plot tool to make a map showing precipitation anomaly during strong El Nino Octobers. That would include 1957, 1965, 1972, 1982, 1987, 1991, 1997 and 2009.


Look at the drier than normal Pacific Northwest west of the Cascades.  Novembers are similar with an even more pronounced dry anomaly.  Many of those years we saw ridging and/or split flow…like what we have been seeing in the maps for the next 10 days.  I remember 1997 was right after I got married…lots of east wind and sunshine with mild temps.


What about December?  Different story.  In many of those years wetter weather showed up during the month


There you go…pretty strong signal for drier than normal weather through Thanksgiving.  That doesn’t mean DRY in late fall,  but drier than normal.  We’ll see how it turns out.

Today was a crazy weather day at the extreme northern edge of the metro area.  Okay, not really metro area but pretty close.  A band of rain set up just to our north and sat over the same area for many hours.  While we saw little or no rain today down here in town, it was dumping buckets of rain in St. Helens and Woodland.  Take a look at the totals:


Good for you folks, a soaking is much-needed for our trees and shrubs.  I don’t see that anytime in the next 6 days though.  We have a weak and splitting system both Monday and late Wednesday.  Other than that most likely dry through Saturday.

Chief Meteorologist Mark Nelsen

Another Way To Look at El Nino Winters

October 16, 2015

10pm Friday…

Nothing groundbreaking here, but two graphics that convey a bit more about this upcoming winter.  A look at the BIG picture across the country.

First, El Nino temperature anomalies across the region for the 6 strong Nino events we’ve seen since 1950.  That’s what we have this year.  Note 5 of 6 winters are generally warmer than normal…when the whole winter is averaged.  Then the bigger image is the composite of all 6 years:


Then the precipitation anomaly for those 6 years, along with the composite of all 6:


3 were normal or wetter than average, 3 were significantly drier than normal.  The composite we often look at says El Nino is usually drier than normal.  But examining the maps you see some years have been a bit wetter than normal but the dry years have been significantly drier than normal.  That skews the composite to the dry side.  By looking at all 6 separately it’s obvious a drier than normal winter is definitely not a lock.

Again, none of this is ground-breaking material, but I wanted to point out that each El Nino is different and the effects are definitely not the same each time around.  I have a feeling in another 50 years, when many of us are long gone, we’ll have a much better idea about the “flavors” of El Nino.

Have a great weekend and enjoy the clouds/showers!

Chief Meteorologist Mark Nelsen

Record Warm Atmosphere Overhead

October 16, 2015

The weather balloon released at Salem this morning found record warm temperatures overhead.  Yes, they still actually fill a balloon and track its movements twice a day.  When it reached the 850 millibar level (about 5,000′), the temperature was 21.8 degrees Celsius!  That’s 71 degrees F.

So what’s the big deal?  Well that’s one of the mandatory levels, one we frequently refer to in meteorology.  You can look at past climatology on the SPC website and see that it was the warmest temperature ever recorded at that elevation over Salem in the 2nd half of October.  This morning’s temp is the big circle.  The average for any date is the yellow line.  Or orange, or whatever it is…I’m a bit color blind.


Note there is one day it hit the same temperature the 1st of November in the past.  But this is the latest we’ve seen such a warm temp otherwise.  This nifty sounding tool from Jim Little’s website shows it was above 70 from around 2,800′ to 5,000′ this morning!  The blue line is the 4-5am sounding.


That’s an incredibly warm atmosphere for mid October.  IF we had solid sunshine today I think we’d have an 80+ day coming up.  But I think with the cloud cover and a bit weaker easterly wind we’ll stay below 80.  Or maybe I’m getting old and conservative.

Yesterday Vancouver broke a record (81) and Portland tied (80)

That’s it, have to plant my cover crop in the garden and ride the bike on the last day it’ll be 70 by noon.  Enjoy your Friday!

Chief Meteorologist Mark Nelsen

Last 80 of the Season in Portland Today

October 15, 2015

Portland hit 80 degrees today.  Technically 80.06 since temperatures are reported in Celsius.  That tied the record for today, 80 in October 1991.


Here are the other high temps around the area:



There have only been two days in Portland’s history that we’ve hit 80 after this date.  That was the 80 on October 16, 2002 and 81 on October 21, 2003.  Looking ahead, there is no weather pattern that would produce mid 70s or higher, so I think we can confidently say we’re done with 80 degree temperatures for this year.

Easterly gradient was stronger than I expected today; peaking out near 7 millibars.  The peak gust of 63 mph at Vista House was the strongest so far this fall.  Corbett hit 49, and Troutdale a 37 mph gust.  Expect a LOT more of that November through February!

East wind continues tonight so low temperatures only drop to 60-65 in those windy locations.  Down into the 40s and 50s for the rest of us.

Enjoy one more warm day tomorrow because we’ll see more typical clouds and showers at times starting Saturday.  That said, Models are still a bit drier than normal over the next 7 days.  The 10 day GFS total precipitation is less than 1″ over most of the Willamette Valley:


The ECMWF shows under an inch as well.  So a bit wetter, but not a real wet pattern coming up.

Chief Meteorologist Mark Nelsen

We’re Living In Warm Times

October 14, 2015

10pm Wednesday…

We are living through a historic warm period.  No, not the new record for days above 90, 80, or 70 here in Portland. (But we will break the 70 degree record tomorrow)


Not the hottest summer on record, or the warmest winter on record, or the warmest January and June temperatures ever recorded at Government Camp (70 & 93).

I’m talking about the BIG PICTURE.  We have been consistently warm for almost two years now.  The last time we had anything close to a cool month across a good portion of the Pacific Northwest was way back in February 2014!  Yes, we had a cold spell last November, but the warm temperatures in other parts of the month cancelled out that cold.  201411

February 2014 was below normal here, although not really a “cold” month.


You have to go all the way back to December 2013 to find a COLD month


So far this year (through September) is the warmest on record in most of the Pacific Northwest.

In Oregon climate zone #2 (lower elevations westside) it IS the warmest on record:


Most likely next year will be warmer than normal as well with El Nino dominating the first half of the year.  Calendar year 2014 was the 2nd warmest in our area.

This is quite a turnaround from 2010-2011 when short-term trends showed cooling through the early 2000s.  During that time I would sometimes get emails from critics about how our climate was “cooling”.  Well, if you cherry-pick the data you can often find a trend that agrees with your view.  I prefer to look at the real big picture:

Our climate is slowly warming (regardless of the reason) but the extreme warmth of the past 1.5 years is likely a highly anomalous event that may not be repeated for a while.

Many times I’ve discussed the reasons for the warmth:

  1. Upper level ridging (high pressure) has tended to want to hang around the West Coast or just west/northwest of us for extended periods beginning in January 2014.
  2. Warmer than normal sea surface temperatures in the eastern Pacific.  If air comes off the ocean much of the year then that air will be warmed more in this case.

It’s possible #1 goes away anytime, but #2 will likely stay put through this El Nino winter.  Thus another mild winter as mentioned in my El Nino postings (see tabs above main blog posting).

If we swing to La Nina conditions next year, that could very well put us back to cooler again.  But in our gradually warming climate the “cool years” will not be as cool in the future.

Chief Meteorologist Mark Nelsen

ECMWF Monthly Maps

October 12, 2015

For hardcore weather geeks only…

Hmmm, not quite what we were seeing last week at this time.  The ECMWF monthly run shows upper-level ridging quite persistent over the next 4 weeks.  Here are the 4 weekly maps:





Notice ridging wants to stay closer to us.  Here are the 15 day anomalies from the GFS, GEM’s most recent runs:

m500za_f360_bg_NA (1)


This is a wet pattern in the last few days of October…quite a bit different.  Hmmm, disagreement is always interesting.

Chief Meteorologist Mark Nelsen