Colder Northwest Springs?

May 4, 2011

Does it seem that our Springs have been getting colder?  You’re not crazy…take a look at the chart.  Note the number of 60+ degree days up to May 4th each of the last 8 years.  This year we’ve only seen 10 days (4 of those since Sunday), which keeps us at the fewest 60 degree days ever at PDX at this point in the season.  1955 is nipping at our tails though.  That year we had just 11 days so far.  The summer following was cool and frequently cloudy.  You may remember comparisons to 1955 during last summer’s cool spells.  That year we were between year 1 and year 2 of strong La Nina conditions.  Of course we are just finishing up a La Nina right now, with models showing us gonig neutral, back into weak La Nina, or into a weak El Nino by Fall.  So a little different this year, but interesting nonetheless.

Now if you look at the chart it appears that we are trending colder the past 8 years.  However for TV purposes I could only fit 8 years on the chart.  The 5 years previous were all in the 17-26 range which tells you the mid 2000’s were unusually warm too.  You could say we were spoiled by some nice warm early spring weather for parts of 2004-2007 , then back to more typical weather in 2009 & 2010.  For 2008 and this year we’re under the classic cool La Nina spring pattern with upper-level lows moving overhead or diving south just offshore.  That’s the reason for the unusually cold weather.

I don’t see a ton of rain the next week, but definitely cool and showery Saturday and Sunday.  Huge disagreement in the models beyond next Tuesday with some digging a trough farther offshore, warming us up on the West Coast.  Other models show the cool trough coming right in over us next Wednesday or Thursday, pushing the cool weather into mid-May.

Garden update:  I got the cool weather veggies planted today in the warm sunshine.  In warmer Springs I’ve done it a month earlier, but, well, it’s not a warmer Spring.  Ducks pooped in some of the beds too which added a touch of fertilizer…sweet.  I also noticed something; I think the wisteria plant buds were frozen during the early freeze in November!  I’ve never had that happen.  They all appear to be dead and there is no green on the inside of the bud, they just rub off.  Anyone else have the same thing happen?  They were all 4-6 years old too!  Lots of the clematis did the same thing with a pretty widespread die-off of the tops, but they are putting out growth down below.  It was definitely a killer, or stunting, freeze for some plants.  The 1955 November freeze a week or so earlier and even colder must have really caused a lot of damage.

Chief Meteorologist Mark Nelsen