Brrr! Mark Had A Cold Bias This Summer

September 2, 2015

10pm Wednesday…

A post for the real hardcore weather groupies…

Let’s say you’re just sitting at home in…let’s say…Orchards, or Stevenson, or Tigard (pick your own town).  You’re thinking “it seems like temperatures were often warmer than forecast this summer“.

Well, you’d be right.  Just for “fun”, I made a spreadsheet with my 46 different forecast high/low temperatures from June 1st to August 31st.  Then I compared those forecasts to reality.  The red bars below in the charts represent days in which my forecast was too warm.  Blue bars mean it turned out warmer than I expected.

Yep, on the high temps I was too cool 30 days and too warm 9 days.  The rest were right on.  Notice the big spike in late June.  That was our first attempt at 100 degrees, then clouds/sprinkles moved through instead.  Oops.  But you can see the vast majority of the summer our forecasts were consistently just a few degrees too cool.  Model MOS forecasts were consistently too cool as well, so I’m quite sure the above normal sea surface temps (and lack of marine cloud formation) had a lot to do with it.



How about low temps?  It’s been another summer of record warm low temps.  These were split a bit more evenly.  There were many evenings when I went well above the MOS values knowing that models were consistently running too cool.  So I was too cool 23 nights and too warm 15.




Chief Meteorologist Mark Nelsen