10:00 a.m. Wednesday, October 19, 2011

If you like autumn sunshine, I know you must have loved the weather across Western Washington yesterday.  The sun was out and temperatures were running well above average for mid-October.  Check out the highs from Tuesday afternoon… mid to upper 60s for most spots around the sound with 70s along the coast at Forks and Hoquiam.  Other spots that soared into the 70s were toward the Cascade foothills.  Enumclaw hit 70 and Fall City recorded 71 degrees.  The 67 degree high at Sea-Tac was only 3 degrees shy of yesterday’s record high temperature of 70 degrees.

While the numbers speak for themselves, I was convinced of the sheer beauty of yesterday’s weather when one of my co-workers said it was “nice” in his Mill Creek neighborhood.  Graphic artist Craig Farrar, an Alaskan native who feels at home in the cold, seemed fine with yesterday’s sunshine.

Looking outside today, it is apparent that the 70s are not sticking around.  Clouds are increasing and temperatures will be running 5 to 10 degrees cooler today.  Most spots will be topping out in the upper 50s and low 60s this afternoon. 

Are 70 degree temperatures now in the rear view mirror for 2011?  The likely answer is yes.  Yesterday may have been the warmest day we see for the rest of the year.  As we head into late October and November it becomes increasingly difficult to hit the 70 degree mark.  The days are getting shorter and the sun angle is much lower.  Average high temperatures are now in the 50s with records at Sea-Tac in the upper 60s/low 70s between now and early November. 

In order for us to get near 70, we have to see an offshore flow.  That is the wind that blows from the land out to sea.  That easterly wind cuts off cooler air coming in from the Pacific Ocean.  The air further warms as it descends the Cascade Mountains, typically bringing the warmest weather toward the foothills like we saw yesterday. 

Looking at the long-range forecast that takes us into November, it’s looking unlikely that will see a day as warm as yesterday.  The rest of this week is dominated by an onshore flow bringing cooler air and showers across our area.  Forecast models are putting a ridge of high pressure over us around Wednesday next week that will likely bring us some more sun.  At this point, it’s not looking like temperatures will be as warm as yesterday.

Here’s a climate statistic that may give you a little hope for one last mild day before winter hits.  On November 3^rd last year, Sea-Tac’s high temperature hit 74 degrees.  That was not only a record high for that date, but also the second latest 70 degree temperature on record at the airport.  The only other time we have seen a 70 degree reading that late in the year was on November 4, 1949.  

-Sam Argier, KIRO 7 Morning Meteorologist