Warm Spell Ends Tonight

March 12, 2018

7pm Monday

Now THAT was a nice early spring warm spell wasn’t it?  Check out the high temperatures today; several stations are likely to tie or exceed records for the day (Salem and some coastal stations)

Todays Observed Highs OrWa 2017

Portland didn’t quite make it to 70, most likely due to a little TOO much easterly wind.  Notice the coolest spot in the metro area was Troutdale; well exposed to the gusty east wind all day long.

PDX Observed High Today

I now owe Brian MacMillan an iced coffee tomorrow afternoon…I was going for 70.

Even if today is the warmest day of March (a possibility), it’ll be higher than last year.  In March 2017 we didn’t even get above 61 degrees!

March Warmest Temp

Notice when we get above 70 it is typically in the latter half of the month.

We’re headed back to “reality” the next 5-7 days, which means highs in the 50s and occasional showers.  An upper-level low will linger along the West Coast with most energy headed into California.  In fact rain will be significantly heavier in California than the Pacific Northwest.  The result should be a mix of clouds, sun, and occasional light showers Wednesday through the weekend.  But I don’t see an unusually wet weather pattern.

So far this March I’ve been surprised we haven’t seen a pattern that would bring snow down into relatively low elevations; typical in late February/March in La Nina winters.  The pattern for the next week does not look especially cool either, with a snow level between 2,000′ & 4,000′ most of the time.  There is no sign of snow sticking down around 1,500′ or lower…I’m taking my snow tires off after a trip to the mountains Thursday.

Chief Meteorologist Mark Nelsen

Our First Spring “Mini Heat Wave” Sunday & Monday

March 9, 2018

5pm Friday

Today was a pleasant day with just a few sprinkles here and there.  Of course the first week of March has been cool across the West, leftovers of the cool troughing that has lingered over us (or just offshore) since the middle of February.  But get ready for MUCH warmer temperatures the next 3 days.

Spring in our area (March through May) is typically a series of wet or mainly wet days interspersed with a few dry days.  Occasionally from now through May we’ll see a period of temperatures well above average; a spring “heat wave”.  Obviously it isn’t really hot and sure isn’t a real heat wave, but just much warmer than the average high for the date.  This is going to happen Saturday through Monday, especially Sunday-Monday.  Our average high is in the mid 50s in the middle of March, and we’ll be a good 10-15 degrees warmer than that.

Why so warm?  Several reasons:

  1. A cold and deep storm out in the Eastern Pacific will push warm air north along the West Coast

2. Easterly “offshore” wind will be blowing through the Gorge and over the Cascades.  This time it won’t be a cold wind (except mornings east metro and western Gorge).  An offshore wind in March helps warm us up a bit and dries out the airmass nicely.

3. Lots of sunshine.  Saturday will be mainly sunny, although during the late afternoon & evening skies WILL cloud up as a weak disturbance passes overhead.  Sunday should be totally sunny.  Monday starts sunny but skies cloud up in the afternoon.

How warm could we get?  850mb temps (temp in Celsius around 4,000′) peak out around +6 to +8 on Sunday and +8 to +10 on Monday.  Past cases say that if everything is perfect, this setup in March could give us high temperatures in the lower 70s.  But in the case of this weekend I don’t think it’ll be “perfect”.  Lots of clouds arrive midday/afternoon Monday.  So for now we don’t have a 70 in the forecast.  Still, highs between 65-70 are quite deluxe for March 11th/12th!

This won’t last long, we’re headed back to typical cool showers Tuesday and beyond.  Model agreement is good on this.  Check out the sharp change beginning Tuesday on the ECMWF ensemble forecast for Portland


  • Enjoy our first real warm spring weekend!
  • It won’t be totally sunny Saturday & Monday, but you’ll enjoy the warmest temperatures we’ve seen so far this season with ample sunshine.
  • Record highs are unlikely, although Monday will be close.


If you live in the eastern metro area close to the Gorge, or in the western Gorge, the east wind will blow the next 3 days.  Sure, it won’t be a real cold wind, but it’ll feel much cooler than 60-70 degrees.  Peak gusts will likely be in the 30-50 mph range in the Gorge and 20-35 mph range in the east metro area (east of I-205).  This happens during March warm spells, just like in mid-late October when that wind turns a bit cooler.

How many of you remember this early March “heat wave” in 2005?

I’ve never seen anything like it in the first half of March during my entire career.  Day after day with solid sunshine and highs in the low-mid 70s.  Note the 5 consecutive record highs that still stand 13 years later.  This is the ONLY such occurrence in Portland’s daily weather records anytime in the year.

Chief Meteorologist Mark Nelsen



Windiest Day of the “Storm Season” In Portland

March 8, 2018

7:00pm Thursday

What a blustery March day!  The wind was a bit stronger than I expected along the coastline, but reasonable inland.

Peak gust at PDX was 42 mph around 8:30am…I slept through it since I work the late shift.

Wind Peak Gust PDX

Hard to believe but that IS the highest gust we have seen since last April’s windstorm.   This winter has been marked by a real lack of southerly wind events or storms.

Here are some other gusts in the metro area.

Wind Metro Peak Gusts Today

All of the airport locations were between 30 & 50 mph.  That’s a bit stronger than I expected and pretty impressive for a weakening low pressure system moving up the coastline!  I forecast 30-40 mph gusts.  Those numbers only include the southerly wind, not the earlier strong east wind coming out of the Gorge.

Now out on the central Oregon coast it was quite strong.  70 on the Yaquina Bay Bridge and 60-70 within a few coastal towns.

Coast Peak Wind Gusts

Once again this was one of the strongest events of our storm season.

Coming up we have the nicest/warmest weather of our early spring season.  After leftover clouds and maybe a shower tomorrow it appears high pressure will build over the western USA through Monday.  A deep upper-level low develops well offshore and pumps warm air up over us.  This can be a classic setup for very warm spring temperatures.  As of today models are showing 850mb temps up around +7 to +10 both Sunday and Monday.  What happens if we combine that with offshore wind and mainly sunny skies (especially Sunday)?  Past cases tell us we should top out between 67 & 73 degrees in this setup.

An issue for some of us is that the east wind will be blowing all 3 days of our early spring warm spell.  It’s not going to feel as warm in Troutdale, Camas, & into the west end of the Gorge.  Gusts are likely to be in the 30-50mph range out there.  But that’s what happens in March when you get an easterly wind.

Chief Meteorologist Mark Nelsen



Looks & Feels like Spring! Plus Winter 2017-18 Wrap-Up

March 6, 2018

5pm Tuesday

Feels like spring doesn’t it?  Seems appropriate since we’re heading into the 2nd week of March, but that sunshine and afternoon temps near 60 sure felt nice didn’t it?  Before looking forward, let’s look back at this winter we just “endured”.  That’s a bit dramatic, since the only thing we had to endure was some slippery driving Christmas Eve/Day and again the last week of February.  What an easy winter west of the Cascades!  Meteorological winter has now ended and we are in spring…the 3 months between winter and summer.  Calendar makers prefer the late March to late June definition, although that doesn’t follow the sun’s movement or weather very well.


Take a look at temps…a slightly cool December, a “crazy warm” January, then a cool February.  February of course is interesting because the first week or so was very warm, then the next three weeks were cool.  Overall it was a “warm” winter.


Then precipitation…drier than normal

December was well below normal and in February we only saw half of our typical precipitation.  January was just slightly wet.

Note the dry weather covered most of the American West this winter.  The only wet areas were up near the Canadian border, northern Washington/Idaho/Wyoming, and all of Montana.  You can see the result on current snowpack:

Well below normal in Oregon (even with a snowy 2nd half of February).  You can’t make up a whole season of low snowfall in just a couple or three weeks.  But check out those numbers in Eastern Washington, north Idaho, & Montana…big snow there!  This means the Columbia River will have plenty of water this summer, even though most streams in Oregon will be running lower than normal.  Of course if we suddenly turn wetter through May, things could change.


Looking ahead, we’ve got a classic spring mix of wet days and some sunshine and warm temps too.    Take a look at the ECMWF 850mb ensemble temperature for the next 15 days.

You can see the above average temps right now, then another warm period Saturday through Monday.  Then it’s pretty obvious we’ll be entering a cool/wet period by the middle of next week.  There seems to be pretty good agreement with the general pattern, although some disagreement on how quickly a cool trough moves inland early next week.

It appears to me this means we have some nice spring weather coming up again tomorrow, plus this coming weekend.  The ECMWF ensembles show the warmest weather so far this season for Sunday/Monday; highs into the lower 60s.  These numbers are likely underdone, at this point something around 65 or so seems reasonable with offshore flow Sunday/Monday.


You can also see the period of cool/wet weather Tuesday and beyond next week.  So enjoy some mild weather for the next 6 days, classic cool/wet March weather will return!

Chief Meteorologist Mark Nelsen


Winter Is Over In the Lowlands; What Does That Mean?

February 27, 2018

Winter 2017-2018 is done; time to stick a fork in it!

What kind of a statement is that?  It means I’m quite confident we’re done with most of our typical winter weather events.  But not all!

First, a quick look at “winter” shows we have been a bit warmer and drier than normal; definitely not a typical La Niña winter.  Only in the 2nd half of February did things finally kick into gear.  Take a look at the temperature anomaly the past 90 days in the West

Precipitation anomaly since late November shows most of the West has seen a very dry winter:


Looking at the maps ahead, I don’t see an outbreak of cold arctic air.  For that matter I don’t see unusually chilly air for this time of year.  That plus the calendar turning to March tells me we’re done with most of these weather events for the season

Sure, we can still get a chilly east wind, but in March we don’t get long periods of cold easterly wind.  As mentioned I don’t see a setup for an all-day type snow event that would keep roads frozen/snowy.  It’s too late to get a damaging arctic blast; and nothing is seen on our models.  I’ve never seen widespread flooding in March, although I remember the flooding around Salem a few years ago in March.  Again, that was localized.

What actions can YOU take at this point?

There you go.  Basically it’s time to “de-winterize”.  Now if you live in the foothills like me, I’d leave the snow tires on a bit longer to see what’s ahead next week.  Same thing if you regularly go up/over the Cascades.

What might we still see in March?

Of course in any year we can still get a brief wet morning snowfall even at the lowest elevations in March, but in these La Niña winter/springs the chance of that happening is higher.  Remember March 2012?  That’s an extreme version of what can happen, but we saw significant sticking snow overnight hours several times, including at the coastline.  In fact even later this week (mainly Friday) we could see brief snowfall in the overnight/morning hours.  That’s assuming we have enough moisture when it’s cold enough.

Obviously we still get freezes in March, but they become milder and a temperature below 25 is unlikely for most of us.  And we can sure get a windstorm in March!  Remember last April?  Gusts 45-60 mph in the metro area in the first week of the month.  That IS the latest I’ve seen a windstorm; it’s more common in March.

Chief Meteorologist Mark Nelsen

Snow Showers Tonight; White Dusting For Some Monday AM

February 25, 2018

8pm Sunday

Earlier in the winter this would have been a BIG deal.  But we just went through a week of seeing snow at times, so now a forecasting of a “possible dusting” in the lowlands and a half inch up at 1,000′ doesn’t seem quite so dramatic does it?

A cold front passed through the area this afternoon and behind that is a very chilly airmass.  In fact by daybreak the sticking snow level should be just about on the valley floor (sea level).  The mixing south wind will be gone by that time too.  But the limiting factor for snow tonight is the showers drying up later tonight just when it’s finally cold enough to stick at the lowest elevations.  Notice it’s too warm for most of us at 8pm.


Because of this I think it’ll be tough to get more than 1/2″ anywhere in the metro area below 1,000′ or so.

Snow Tonight Forecast 1

So ANY OF US IN THE LOWEST ELEVATIONS COULD WAKE UP TO A DUSTING OF SNOW ON THE GROUNDI don’t expect the snow itself to be a significant issue for the morning commute.

As mentioned in the graphic above, a bigger issue may be spots of ice on some roads by sunrise.  We’ll have a few wet areas, partial clearing overhead, and a calm wind by morning.  That combo will likely allow temperatures in some areas to fall to/below freezing.  I think that’s most likely central/west metro area where we get more clearing.

The rest of Monday will be uneventful with partly cloudy skies, a few sprinkles/flurries, and highs well into the 40s.

Next chance for lower elevation snow will likely be late week as cold showers return.  As of now there is no sign of a widespread snow event this week…as the calendar turns to March.

Chief Meteorologist Mark Nelsen

Winter Snow Stats

February 24, 2018

10am Saturday

Temperatures rose into the upper 30s last night with the southerly wind as expected.  It was nice that the warming shown overhead by models appeared too.  Snow showers changed to a rain/snow mix or just rain at the lowest elevations during the late night hours in the metro area.

So we didn’t have sticking snow yesterday or last night.  But was that it for the winter?  History tells us that’s most likely.  But with cold upper-level troughs still swinging through for another week we may somehow eek out another 1/2″ (or less).  We’ll see.

It’s snowing heavily in the Cascades and that continues through the weekend.  Note 2 to 3 feet forecast through early Tuesday


Here are the winter stats so far:

  1. We have had FOUR official snowfalls.  That’s four with measurable snow at the Portland National Weather Service Office in Parkrose.
  2. February 2018 is the snowiest February since 1990.  It doesn’t take much, February snow isn’t very common.  Seems like we only get February snow 1 out of 3 years.
  3. We have had TWO freezing rain events, although one was just barely measurable and isolated to right along the Columbia River (Dec. 26).  Plus we’ll all remember that as one.
  4. Peak wind gust?  East at 41 mph…twice.  December 6th and January 15th.  Wind has been unusually light this year in the city; a real lack of south wind events.  We only had the strong east wind event in early/mid December; that’s it.

Winter Snow_Ice Totals So Far

Chief Meteorologist Mark Nelsen