Worst Spring Ever In Portland? I’d Say So!

May 31, 2011

June is only 2 hours away…really hard to believe isn’t it?  What a strange and cold spring it has been.  As meteorologists, we generally consider the three spring months (if there are 4 seasons) to be March, April, and May.  This is the only spring I remember where we’ve seen no decent warm spell.  Yes, of course we had all of three days around 70 a week or so ago, but that’s it. 

So is it the WORST SPRING EVER?  I think so…here’s why:

1.  The March-May average temperature was 49.33 degrees, the 4th coldest in Portland’s history and the coldest in 44 years!.  The 3 colder were 1955, 1964, and 1967.

2.  The March-May total rainfall (with 2 hours to go) is 14.41″  That’s the 2nd wettest in Portland’s history.  And only .09″ below the wettest year of 1997. 

So how wet were those other cold years?  All three were near or well below average rainfall-wise.  Those springs were chilly, but not wet like this year.

And how cold was the wettest spring, 1997?  Not very cool…in fact during May 1997, there was a 10 day stretch in which 7 of those days made it into the 80s!  I remember that one clearly…that was a fantastic May. 

Put those two together and I say we haven’t seen such a combination of cold and wet during the three spring months in Portland’s history, at least back to 1940, which is when airport records began.

 

Current Weather:  Nice cluster of showers really giving a soaking to the extreme SE part of the metro area this evening.  It appears that a marine push coming in from the northwest through the rest of the metro area kept the convection just to the south.  You could see a swift movement of lower clouds coming in from the northwest on our Skyline camera around 6-7pm.

Looking ahead…models are still in line for the big, brief warmup this weekend!  Easterly flow commences overhead Friday afternoon and continues through early Sunday.  850 mb temps went a little crazy on the earlier GFS (+18 deg C!), so I based an 85 degree temperature forecast Saturday from our chart, which shows a possible high between 83-88 degrees based on a +15 deg 850mb temp and offshore flow.  Most important, models are not shifting the low any closer…a very good sign of model continuity.

Chief Meteorologist Mark Nelsen


Willamette River: Highest in 14 Years

May 31, 2011

Here’s a nice graph from the USGS showing the past 15 years of water level on the Willamette River.  That’s right at the Morrison Street gauge.  Today it peaked at slightly over 17′, just a foot below flood stage.  That’s the highest the lower Willamette has been since early June of 1997.  As a result the city of Portland closed the East Bank Esplanade for the first time since it’s construction in the late 1990s.

Is it a coincidence that at the same time the Columbia is seeing its highest level in 14 years as well???  No, because the Willamette River is not REALLY flooding, but the Columbia River is.  The two rivers are connected in the northwest part of Portland, so if one rises the other one does as well.  If there was a ton of water flowing down the Willamette River you’d expect high water in Salem and Albany, but that’s not the case.  Right now the river is 13-14′ below flood stage at those two gauges.

So how high CAN the Willamette get in Portland?  Here are the numbers…

The two highest crests both occurred in June; similar setup with water coming in from major Columbia River flood events.

33.0′  June 7, 1894
30.0′  June  1 & 14, 1948 (Vanport Flood)
29.8′  December 25, 1964 (Winter Flood)
28.7′ February 2, 1890 (Winter Flood)
28.55′ February 9, 1996 (Winter Flood)

During the first 3 floods above (maybe the 4th), water flowed into downtown Portland, up to 5′ in spots during the 1894 flood.  You can find pictures around the Portland area showing this flood.  Imagine paddling a canoe down 3rd avenue or SW Oak St. on a sunny day in June (the image below)!