March 2017: Warmest and 4th Driest Ever!
So the final numbers are in for the month of March. As you all know, it’s been a pretty toasty one this year, but I had no idea exactly HOW toasty. Our average temperature at DLS was 52.9 degrees F, with a high of 65.3 and low of 40.5! That blows away the old record from 1968 (52.0), and it’s a full 1.5 degrees warmer than March 2015. Most amazing of all was the fact that we had a seven-day stretch above 70 degrees, including an 81 on the 27th!
Also it was historically dry, the 4th driest on record at The Dalles. Only 0.33″ of rain, and it fell on only two days this month. All that sunshine is one of the main reasons why the warm departures were far more concentrated in the days than in the nights. (In fact, with all the clear nights and dry offshore flow this month, I’m surprised the average diurnal temp swing wasn’t even larger!)
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……Okay, you probably guessed the “APRIL FOOL” joke by now, given the calendar date of this post, and the actual weather this year. So what REALLY happened in March 2017?
Well it was wet…2.36″ of rain. We just barely edged out 2012 and 1989, to become the 5th wettest March on record at DLS airport. There were 19 days with measurable precip this month! That and snowmelt from February, are the main reasons why our hills have been getting so green the past couple weeks. Normally I’d say that last fall’s unusual greenery helped us along…except that all the cold and snow this winter left both native grasses and lawns, pretty beaten up. (Fall growth typically gives the grasses more of a “foundation” for springtime, once it arrives in earnest.)
As for temperatures…hard to believe, but it was actually slightly WARMER than the 30-year norms this March. Averaged high was 55.4, which is about a degree and a half cooler than average. But the nights tended to be on the mild side, so that the mean temp was actually 0.5 degrees F above 1981-2010 climo. And here I was…all thinking we were destined to get a historically cold March this season, including multiple teases of snow at the lowest elevations!
You might think that after the cold winter, the near-average temps this March would have allowed a lot of the vegetation to have “caught up” with normal seasonal timing. But the photos suggest far from it. We are still at least 1 1/2 weeks behind schedule, for MOST early flowers.
Magnolia and pink peach just now coming into bloom:
Again…both of these bloomed about one month earlier in 2015. Now for some actual photos that show comparative phenology between Spring 2015 and Spring 2017.
Here is the West 10th Street Apricot, from Feb. 28, 2015:
And here is Mar. 30, 2017, a full 30 days later in the season:
Notice how the PLANT looks the SAME, even though the DATES are wildly DIFFERENT. In this case, the phenology is the “control” variable while the date is the “partial” variable.
When it comes to bigleaf maples photographed just west of Chenowith Creek on Highway 30? Here are a couple photos that use date as the control variable instead (same date, different phenology):
Wow, a nearly full crown of leaves vs. buds barely trying to open! I’m not sure if it takes a full month to go from bud break to leaf crown in a spring that progresses “normally,” but I imagine it’s pretty close to that. In any case, we can do a phenological control by observing this specimen throughout April 2017 (and possibly early May!?), until the crown looks roughly the same as the End of March 2015. Then another photograph (hopefully this time of better quality than the one from March 2015!)
In any case…this spring looks nearly as “behind” as the spring of 2009 did, when I visited in late March! That year January and February were milder than this year, but March was much colder with a tease of near-arctic air in the 2nd week of the month. What does all of this mean? It means that (at least in our climate in the late 20th/early 21st century), the timing of early spring hinges heavily on what happens in mid- to late winter. You cannot ségué directly from a cold/snowy winter into a flowery spring, even if you quickly flip from temps in the 20s/30s in February to a whole bunch of 60s and 70s in March. The bulbs and flower buds seem to need a period of mild weather in order to wake up, after the “deep” sleep that a cold winter imposes.
Here are the official monthly outlook maps for April, first temps and then precip:
If we get average temps throughout April, then I bet our phenology WILL start to catch up in a meaningful way. If that’s the case, then Winter 2016-17’s final “shadow” will fade out over the next 2 or 3 weeks, as the “mid-spring” flowers and leaves arrive closer to normal timing.