I’ve been sick for the past 10 days, with my worst cold infection since the pre-Covid era.  Only the first 3 days were really acute; the problem is that the symptoms are very slow to leave.  I was going to write this blog a few days ago, but didn’t have the energy to focus clearly.  

 

In a way, my sickness is a perfect metaphor for the weather over the past 5 weeks.  Spring 2022 is shaping up to be possibly the coolest and wettest spring we’ve seen since 2011 – and the chilly pattern is stubbornly persistent.  To be clear, there’s nothing “wrong” with a chilly and wet spring in the Pacific Northwest from time-to-time.  It’s a normal feature of our climate cycle, and in this case, an important counterbalance to the abnormally DRY springs we’ve seen in recent years.  Our region desperately needed the rain and mountain snow after last year’s unprecedented drought conditions.

 

Nonetheless, it is pointless to deny that cold/wet springs are often a nuisance from the perspective of daily human life.  Gardening and agriculture can be stunted.  Outdoor activities are difficult to enjoy due to the lack of mild and dry weather, and prolonged mountain snow and valley rain curtail hiking opportunities.  

 

 

Let us take a review of the 2022 spring season thus far, as well as some thoughts on how late spring & summer might shape up this year.

TEMPERATURES

Nothing symbolizes our chilly spring quite like the historic Portland/Vancouver snowstorm on the morning of April 11.  That day was also the coldest overall April day (42.0 deg F) since 2008.  Here is a chart of temperatures for the entire spring season since March 1, at PDX:

One interesting tidbit:  March was actually 1.6 degrees above normal,  though most of that was due to warmer nights.  Daytime high temps were very near normal.  You can see it in the graph above.  The top of the brown zone represents the normal daytime high, and the bottom edge of the brown is the normal nightly low.  You can  notice how on the left half (March and the 1st week of April), the high temperature is above normal for a few days, then below normal for a few days.  

But beginning around April 8-9, we entered a pattern where most days were significantly cooler than normal, with only a few days making normal or slightly above.  In fact the pattern is so pronounced, that if you step back and look at the entire chart, the “trendline” in high temps from early March through early May is nearly horizontal.  Basically, we’ve been stuck with ‘March-like’ temperatures for nearly all of the past 2 ½ months.  Majority of days are cloudy and in the 50s, with a handful of 60s and very few 70s.

After running 1.6F above normal in March, we slipped to 3.1F below normal for April and 4.3 degrees below for the first 13 days of May.  It’s definitely been cooler than normal, but not as cold as spring 2011.  

PRECIPITATION

March was nearly a full inch drier than normal.  Then April was the wettest on record at PDX, with 5.73” of rain (nearly 3” above normal).  So far May has been quite damp, with 2.08” of rain over the first 13 days.  We’ve nearly made our normal May rainfall, with over half the month remaining!

Just as with temperatures, the trend for rain was pretty normal for the first 5-6 weeks.  Then a sudden turn to wet in the 2nd week of April.  We’re currently running well above normal for the spring season, though not as anomalously wet as 2011.  (Last year, 2021, was by far the driest spring in PDX history.)

PHENOLOGY

Finally, here is an accumulation chart for “growing degree-days,” that essentially tells you whether plant activity is “ahead” or “behind” at a given point in the season.  

We were actually running somewhat ahead of normal phenology at the beginning of April.  Then we slipped into a persistent chilly pattern, causing our gardens to begin falling behind instead.  The warmest and earliest spring on record was in 2016; that year we had a ton of days in the 70s/80s from late March through early May.  While our GDDs are currently running below normal, it’s not nearly as bad as it was in the worst of years (1964).  It’s also nothing like 2011, when the spring growing season was very stunted due to a chilly March as well:

I think what makes spring 2022 so depressing is that we haven’t seen the typical seasonal “progression” toward warmer and drier.  Temperatures essentially stagnated for more than 2 months, and rainfall actually increased as we moved into April and May.  If we had instead seen unusually chilly temps for the first 5 weeks, followed by normal conditions thereafter?  I doubt people’s moods would be too gloomy at this point; the April and May sunshine would be a welcome reward after all that cold March rain (and wet snow?).  Phenology would have been delayed by the cold March; then everything would have rapidly burst into bloom once the weather warmed up in April and GDDs began to accumulate.

Some of my friends are already planting tomatoes outside this week, but I’m going to wait until at least the last week of May (if there’s a warm spell), or early June if there’s no warm spell.  The general rule in the western valleys is that you never want to put out tomatoes before May Day, no matter how warm the spring is trending.  But if the spring is chilly and damp, then it’s prudent to wait until after Memorial Day instead.  (The week after Mother’s Day is usually a good benchmark for a “normal” spring.)

LOOKING AHEAD

After a brief stint of normal-ish temps this weekend, we’re going back into cool troughing for all of next week!  I’m not going to post a bunch of model maps, but the basic idea is that Thursday/Friday is looking like the best chance for significant rain this coming week.  The long-range outlook suggests that the chill will linger until at least next weekend:

None of this surprises me for a La Niña spring, especially one where the cold anomalies along the equator are persisting deep into the spring and early summer months.  (Most La Niñas begin to fizzle out in March or early April instead.)  My gut feeling is that we can expect cool anomalies in our region to continue throughout most of May and likely a good chunk of June.  What’s less clear is if the wet pattern continues.  We’re getting close to the time of year when the “rain faucet” often shuts down for the summer; usually this happens sometime between mid-May and mid-June.  Sometimes cool-ish weather persists for a few weeks after the rain dies down; we can just get a lot of overcast days in the 60s/low 70s with occasional light sprinkles.  But there are some years where June remains wet; this last happened in 2020.  

Fellow WeatherTogether blogger Charlie Phillips recently wrote an elaborate blog explaining the ins and outs of El Niño and La Niña; it’s worth a read if you have time.  

 

One last thought:  Will this be an infamously cool PNW summer, the kind that makes outdoor enthusiasts and gardeners extremely grouchy?  It’s too early to tell, but it’s worth pointing out that we haven’t seen a truly cool summer since 2011, so we’re probably overdue.  Please note that at least in Portland, a cool summer does NOT mean rain showers and daytime temps in the 60s throughout July and August.  More likely it would just mean a few more clouds and sprinkles than usual, with a lot of days in the 70s and fewer 80s/90s than we’ve become accustomed to recently.  And even most of the cool summers get at least some warm weather before all is said and done.  That happened in 2011; anomalously cool through June and July followed by a pretty normal August.  With a bit of luck we can also get some spectacular late-summer weather in September, even though it is technically a “fall” month.  That made a big difference in 2011; warm September days turned what would have been a catastrophic wine season into a “merely bad” one.

Karl