Summer on the Horizon

June 29, 2010

A cool evening out there with a chilly airmass and some spots clearing out.  If we get much more clearing the outlying areas will easily drop into the 40s.  Tomorrow looks real nice with clouds breaking up quickly.  After a weak system dropping through Thursday, Friday should be a bit better.  Overall cool late June weather is on tap through at least the early part of the Holiday Weekend, if not all of it. 

One thing I don’t see is a chance for any sort of rain (other than a sprinkle or two Thursday???).  I had hardly noticed, but we’ve seen very little rainfall in almost two weeks.  All of .03″ at PDX in the last 13 days!  After all that excitement about a record wet June, it sure ended dry.  When we look back at the records we’ll see the “faucet shutting off” at mid-month as the dry season began.

So the first part of a typical Pacific Northwest summer has begun, but what about much warmer and sunnier weather?  Well, models the last 2 days have been pointing towards a significant change in our pattern at some point between Sunday and Tuesday of next week.  The NWS folks have put the entire northern and western parts of the country into the “Above Average” category for next week (and beyond).  This is due to models all shifting the weak July jet farther north.  We don’t get a massive sharp upper-level ridge, but 500mb heights rise up to the 582-590dm range.  That’s classic warm-hot July weather.  Some models even have periods of weak offshore flow in there around Tuesday-Wednesday too.  Both the ECMWF and GFS imply temps at/above 90 those days.  Actually I suppose the GFS could push us well into the mid-upper 90s, but let’s assume it’s erratic behavior lately will continue that that won’t be the case. 

The BIG PICTURE shows a general change towards regular summer weather beginning around…the 5th of July!  That’s always a joke of course, but apparently it may happen this year.  Because of that (and last of the season seeds on sale at Freddies), I decided to try planting corn in my garden for the 3rd time this season.  Did that today.  We’ll see if it makes it before mid-September!

Chief Meteorologist Mark Nelsen