El Nino Update

February 3, 2016

9pm Wednesday…

Just a quick (or maybe not so quick) update on how we’re doing with El Nino so far this winter.

Average temperatures across the USA in December/January:


Much of the West has been warmer than normal, mainly the northern half;  Cooler than normal across much of the southern half of the West.  That is about what we would expect in a strong El Nino year with warmer than normal temps across the north due to more frequent ridging.  Yes, it’s been another mild winter, but nothing like the warmest ever we saw last year.

What about rain/snow?  I think we all know the answer; it’s been very wet.  150-200% of normal across NW Oregon and SW Washington.  Most areas along the West Coast except far southern California have been well above normal.  The interior is a bit more of a mixed bag.  What sticks out most is that extreme southern California has been relatively “dry”…only running about average.  One theory for the lack of strong systems way down there (as opposed to other strong El Ninos) is that the unusually wet jet stream has been pushed farther north this time around.  That possibly due to a shift in the warm water along the equator OR the warming climate.  Those are just guesses.  It seems to me we have seen more subtropical ridging near the West Coast than we would typically see in an El Nino winter, but I could be wrong…just an observation.  Of course we still have February/March to soak those areas down south, but there is no sign of a significant change in the next 10-15 days.


This is what I wrote back in the fall (and it’s still on the tab on the top of this page)


The drier part didn’t happen but the mild part did.  #2, #3, & #5 have worked out fine.  We never had a big regional flood, but plenty of localized flooding back in December.  We sure didn’t have an arctic blast either, that doesn’t surprise me.

It’s beginning to appear this wet season/winter is going to be remembered for a VERY wild December (through Jan 3rd) and that’s it.  The rest being mild/wet but quite boring.  That’s assuming we don’t have a total change coming up around mid-February of course.  Yesterday Cliff Mass had a great posting about El Nino (my inspiration)…more maps and charts here:


Okay, let’s talk Cascade snow too.  That seems to be working out quite well.  If you recall, EVERY El Nino since 1970 has brought below normal snow to Gov’t Camp (4,000′).  That’s continuing this year.  Govy has seen 109″ so far this season, 149″ is normal through the end of January.  Every month except December has been below average.  If average snow falls in February, March, & April, we’d still end up with 225″ for the season, below the 270″ average.  Here’s the chart for Govy with the SO FAR numbers in yellow..much better than last year!


Higher up, at Mt. Hood Meadows the season total is of course much higher…271″ so far. Below are the number SO FAR in yellow for them compared to Govy.  This winter seems to be a case of warmer storms keeping the best snow up high…that is what we thought might happen.  I don’t have the average numbers by month up at Meadows so I don’t know how they would end up with average snow from here on out.  Again…FAR better than last year!  And we’ve already passed up the bad El Nino years of 91-92 and 04-05.


Chief Meteorologist Mark Nelsen

Groundhog Day: But What Does It Mean?

February 2, 2016

9pm Tuesday…

It’s that time of the year…Groundhog Day comes around each February 2nd and the media LOVES to see what the furry little rodent says in Pennsylvania.  The practice goes way back to Europe.  Here are two proverbs from England and Germany:

If Candlemas be fair and bright,
Winter has another flight.
If Candlemas brings clouds and rain,
Winter will not come again.

The badger peeps out of his hole on Candlemas Day and if he finds snow he walks abroad,
but if he sees the sun he draws back in his hole.

By the way, Candlemas Day (on or around February 2nd) is the halfway point between the Winter Solstice and Spring Equinox; 40 days after Christmas.  In the past it was sometimes considered the beginning of spring.  That seems a bit early.  But I have a feeling that was for daylight; it’s definitely the beginning of spring with respect to light.  The ancient Imbolc festival is similar, celebrating that midpoint.  You can read about these in GREAT detail on their Wikipedia pages.
But we have our own prognosticator here in Portland.  He’s called BMAC.


Of course that’s Brian MacMillan’s shadow this morning (looks like Slender Man?).  Seems pretty clear cut to me; he sees his shadow and that means 6 more weeks of winter.  If the last 3 weeks were “winter”, that’s fine with me.  The last 20 days of January were very mild.

But wait a minute!  Velda the hedgehog at the Oregon Zoo didn’t see her shadow, according to the folks there.  So I smell a conspiracy once again.  Who can forget the fiasco back in 2012???  I have a feeling that the (very nice) marketing folks at the zoo would prefer that each February be labelled an “early spring”.  “Come on out and visit us!

Or am I just a bitter old weather guy?  Take a look at the pic today:


Hmmm, sure looks like a shadow on the keeper’s collar!  Now in the case of this year we can probably give them a bit of a break; take a look at the 10am satellite image:


Half of the metro area was totally sunny (east side) and areas west of I-5 were mainly cloudy.  So according to the proverbs I get this forecast for the next 6 weeks:


Good news, the western metro area is headed into spring.  But for those of you on the east side…winter continues.


Wow, we’re going to have some tough daily forecasts aren’t we in the weeks ahead?

That was fun, but…


No sign of winter in the next 10-14 days (through mid-February) since we’ll be mild and wet or mild and dry.  Snow levels will be mainly at/above 4,000′ over the next two weeks.  Models are all in excellent agreement on a short-lived (a week or less) very strong upper-level ridge Sunday-Wednesday next week along the West Coast.  500mb map from the GFS Monday AM:


That’s the kind of ridge that gives us 90 degrees in May, or 70-75 degrees in March.  In mid-late February that’s a 65 degree day maker.  However, it’s still early February and strong easterly wind through the Gorge Monday-Wednesday will likely keep us below 60-62 degrees in the metro area.  That said, it’s a real tough call on February 8th-10th.  IF we break the inversion even a little, we’ve got some 60-65 degree days coming up early next week.  That’s FALSE SPRING weather.

For sure the Coast, Cascades, and Cascade foothills are going to be very warm next week.  Central Oregon too.  We will also see lots of sunshine Sunday through Wednesday in all areas with the dry offshore flow.

Chief Meteorologist Mark Nelsen

Friday Evening Update

January 29, 2016

11pm Friday…

Time for the weekend!  In this case it means showers, sunbreaks, and maybe some hail/thunder for Saturday.  Could be an active day…that after a slow January (post-snow).

We ran a story tonight saying Crater Lake NP had huge attendance last year.  A good chunk of that was due to the terrible snowpack that melted quickly.  Earlier Rim Drive opening = more people!

I checked the stats and indeed the snowpack numbers look good down there


January has been an interesting month…one that started cold with some snow at the lower elevations, but then the 2nd half was extremely warm.  Most of the month we saw frequent, but weak, pacific systems moving onshore.  These were generally mild systems so the snowpack didn’t change much through the month.  As a result the percentage of normal has dropped a bit below average on Mt. Hood and the huge numbers to the south have decreased a bit.


Compare these numbers to one month ago:


Still MUCH better than the disaster last year!  Note this graphic is from LAST YEAR…


Looking ahead, we’ll see lowering snow levels over the weekend.  Sunday morning I could see it sticking down to around 1,500′ and down around 1,000′ Monday morning.  That said, it looks mainly dry Monday morning.  After that snow levels rise again so whatever we see in the lowlands Sunday and Monday should be “Conversational Snow”.  That means lots of us see snow showers or snow/rain mixed, but it doesn’t affect our daily lives.  But we tell friends about it and Tweet/Facebook it.

Have a great weekend!

Chief Meteorologist Mark Nelsen

ECMWF Monthly Run Maps

January 28, 2016

3pm Thursday…

Time for another run of the ECMWF out to 32 days.  This one says “winter is over” after the middle of next week.  Yes, I know I’m being dramatic but at least I didn’t put it in the headline for click-bait!

One map for each of the next 4 weeks showing average 500mb height among the 51 ensemble members along with departure from average for this time of the year.  The first week is a little misleading because we have a cold trough over us to start and then a ridge (NEXT weekend) so they average out to near normal.  Basically a change is occurring midway through the week.


Beyond that it’s saying we get ridging through much of February.  Remember, it’s just one extended run of one model, although the message is similar to what it was showing 3 days ago.  At first it’s a full-latitude ridging (dry in California too), then it morphs more into ridging up north and wetter south.


Speaking of next week…

With a colder airmass Sunday night and Monday a weak surface low is shown on the WRF-GFS moving down the coastline.  This can be a good setup for snow to very low elevations.  Someone at a business lunch today said they heard it was going to snow Sunday.  Not sure where that came from because we’d be lucky to get sticking snow below 2,000′ on Sunday.  The ECMWF doesn’t show the low and is drier; but it’s something to keep an eye on for Monday.

There is also the possibility of snow/ice in the Gorge the middle of next week IF moisture returns and IF easterly flow sets up.  Not a good possibility for now, but keeping an eye on it.

Chief Meteorologist Mark Nelsen

Have We Seen the Coldest Of Winter?

January 27, 2016

11pm Wednesday…

Whew, a busy day for the news folks.  That means not much focus on the weather despite record highs at Salem and Roseburg.


Here in Portland there was just enough easterly flow to keep us “cool” at 54 degrees…two degrees below the record for the date.  Note that the 47 degree low “today” (calendar day) is the warmest low temperature since early January.  We haven’t seen frost in almost 3 weeks here in the city either.  A very mild 2nd half of January for sure after a nice and chilly start!

That brings up the question people often ask me this time of year (when temps start to warm).  “Has the coldest weather of winter passed on by?“.  I think that’s quite possible this year.  First, we’ve dropped to 24 at PDX twice in late November.  Then and again in early January the colder suburbs dropped into the upper teens.  Compare that with the past few years:


If we only have a low of 24 that’ll be a bit on the warm side, although not too unusual.  Look at the low temperatures over the past 20 years.  The title refers to last winter, although it may end up being correct for this winter too.


Take a look at a neat graphic from Climate Matters, showing the average date of the coldest winter temperature


We already know our coldest winter temperatures are often in late December, but you can see here it tends to be later in the winter in the Eastern USA, especially in the northern areas.  That’s because widespread mid/late winter snow cover reflects the sunlight well over there.  A wide open path for arctic airmasses to move south over the snow-covered terrain doesn’t hurt either.

The last two big El Ninos featured mild January/February weather so I think it’s UNLIKELY we have anything colder than 24 in the next 5-6 weeks.  Of course we know it’s POSSIBLE this late, but it seems unlikely this year.

Chief Meteorologist Mark Nelsen


The Big Picture: Warm, Cool, Warm Next 16 Days

January 26, 2016

3pm Tuesday…

Time for a look at the general weather pattern.  During the past 30 days the West Coast has slipped into a much more typical El Nino pattern with a bit drier than normal weather north of Oregon and wetter than normal down in northern/central California with most jet stream energy directed to our south.  Sytems have been quite weak (splitting jet stream), but still coming inland with enough frequency to boost our rainfall to average or a bit above in western Oregon.  Cool colors are wetter than normal.  Parts of central California have seen almost double the typical January rain/snow.


We haven’t seen much rain in far southern California…they would probably like some more down there.

Temperatures have been a bit cooler than average across large parts of the West.  We started very cool here in Oregon but now are moving above average the last few days of the month.

anomimage (1)

We’ll end up a little above normal, but not like the 3 degree warm anomaly last month.

Looking ahead to the next 2 weeks…

  1. No sign of an arctic blast for the Pacific Northwest on any model.
  2. Rain should be near normal.
  3. There is no obvious “snow pattern” in the lowlands the next 14 days.  Except for one 24 hour period;  snow levels will be quite low from Sunday night through Monday .night.  But it looks like just dry to me.  That’ll be something to keep a close eye on.
  4. Mild temps continue before that time and return about 10 days from now.


Models have been doing very well (forecasting big picture) lately and are in excellent agreement on pattern changes over the next two weeks.  Warm ridging over us now (it rained at the ski resorts today), then a cold trough over/east of us from Sunday through sometime later next week.   Note the ECMWF 500mb height anomaly Sunday; some overdue chilly air.  It’ll feel like January again:


This is not a very wet pattern and sure enough the ECMWF is basically dry from Sunday through late next week:


The latest GFS (18z) isn’t nearly as dry, but not exactly a soaker either for next week:


The first week of February will be cool though…note those high temperatures drop about 10 degrees from what we’re seeing now.

Then ridging or at least flatter westerly flow returns for the 2nd week of February.  The 500mb height anomaly from ensembles from the ECMWF/GEM/GFS models today for February 10th.  Actually the GEFS is a 5 day average ending on the 10th:

Since I haven’t shown enough maps, here are the 4 weekly ensemble charts from Sunday night’s ECMWF run.  They look “ridgier” in the last two weeks and could be quite warm (fork time).  That said, the actual operational run showed a very chilly airmass over us around Valentine’s Day and beyond with northerly flow.  It showed the ridging farther west.   We’ll see.

Chief Meteorologist Mark Nelsen

Skiing: Best Next Weekend

January 24, 2016

10pm Sunday…

What timing!  It rained part of last week at the ski resorts, then snow showed up just in time for the weekend.  It looked like this at 9am from our camera at the top of Mt. Hood Skibowl


The same sequence repeats for the last 7 days of the month…warmer and occasionally rainy weather Tuesday-Thursday.  Then much cooler Friday-Sunday.  Yes, looks like another great weekend of skiing ahead


Here in the lowlands it’s pretty obvious the dry days are going to be Monday and Wednesday.  A surface low could bring a one day return to “December-like” conditions either late Thursday or Friday.  I’ll be keeping an eye on that.

Chief Meteorologist Mark Nelsen


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