2nd Coolest June in 20 Years; Cool Continues Into Early July

June 25, 2012

Hmmm, seems like I’ve posted on this subject recently…yes, that’s it.  Now I remember…another cool spring and another chilly June.  I created this chart this evening:

It shows our current PDX June temperature (5 days left) running at 60.5 degrees, eclipsed only by 2010 since the very cold June of 1991.  We haven’t cracked the top 5 coldest Junes, but it’s close.  Of more interest may be the fact that the five-year average is the lowest since the early 1960s.  It also happened to be a very chilly 5 year period in the early mid 1950s.  So maybe we were overdue. 

Clearly this has not the case across the rest of the country, wow…look at that continued warming the last 5 years:

There has been no drop in June (or summer) temps when the whole lower 48 our averaged together. 

If someone has A LOT of time (graduate student), they could try to figure out why.  Maybe the incidence of upper-troughs hanging near the West Coast in late spring has increased?  Stronger onshore flow?

I don’t see any significant change away from our cooler than average weather through next week.  Most likely we won’t see a big warmup for the 4th of July.  I have no idea if it’ll be cloudy or possibly showery, but there is no sign of a large upper-level ridge nearby through the first few days of July.  Models are in quite good agreement on this.  Here is the latest 850mb ensemble charts from the 12z ECMWF showing ensemble temps near or below average through at least July 8th:

and the 18z GFS shows ensemble temps are near or below average through July 6th:

Chief Meteorologist Mark Nelsen