The persistent fog that has been plaguing Puget Sound the last several days is almost over.  Before we see the weather pattern switch up, we have another foggy morning on the way for Tuesday.  A dense fog advisory is in effect through noon; visibilities will be at or below ¼ mile.  With temperatures dropping into the low 30s and 20s, some icy spots are also possible on the roads.

Check out the high resolution visible satellite image above.  Low clouds and fog were socked in around Puget Sound and Central Washington on Monday.  The sunniest spots were along the coast and around Whatcom County.

We have had an extremely strong temperature inversion in place.  This is where the air warms up with height as opposed to cooling off like it usually does.  That warmer air acts like a lid, trapping the low clouds and fog at ground level.  Over the past weekend, this inversion has been very close to the ground.  Temperatures start going up once you hit 500 feet.  What’s so amazing, is that areas in the mountains have been much warmer than Puget Sound. 

On Monday, the high temperature at Sea-Tac was only 36 degrees with low clouds and fog socked in all day.  Compare that to Hurricane Ridge which is over 5,100 feet in the Olympic Mountains.  The picture to the left shows all the sunshine up there with a high temperature of 51 degrees on Monday!  Some mountain locations made it up into the 60s. 

Breaking the inversion with some rain

Tuesday marks the 12^th consecutive dry day at Sea-Tac Airport.  With January being our second wettest month on average, it’s really hard to string together 12 dry days in a row.  This will be the second longest dry streak since records began in 1948. 

We’ll stay dry on Tuesday with some sunbreaks during the afternoon.  We have a slow-moving front that will bring rain in Wednesday morning.  The latest computer models bring it in during the morning commute.  Around 0.25” of rain is expected around Puget Sound.  This will mark the start of a wet pattern through the remainder of the week.  Showers will be around with highs in the mid 40s.  Yes, we’re saying goodbye to the fog and hello to our old friend rain.

Have a great day!  

-Sam Argier, KIRO 7 Meteorologist