Sea Breeze Season Begins in the Northwest

Sea breeze is quite an evocative term.

One thinks of a tropical landscape with a cooling onshore wind that develops during the day, best appreciated while one sits on the beach with a sweet tropical drink.  There also seems to be a lot of coastal motels, often a bit seedy, that have "sea breeze" in there name.

But believe it or not, Washington's coast gets decent breezes during the warmer part of the year, and this week, with rising temperatures, the sea breeze season has begun.

First a tutorial for the sea breeze novices. 

Sea breeze circulations occur at the coast, when the land becomes warmer than the ocean as the sun heats the land.  Generally, 5-10F warmer to get some good sea breeze action.   The ocean surface does not warm as quickly for many reasons, include the large capacity of water and the fact the solar radiation can warm some depth of the ocean.  The warmer temperatures over land result in a lowering of pressure, which drives a flow of cool air from off the ocean (see figure).....the sea breeze.

This week there were a few warm days, in which the Washington coast became warmer than the ocean (the water is now roughly 50F)

Consider Hoquiam, on the central Washington coast on April 8th, the warmest day of the week.

Take a look at the temperature plot on that day (see below). About 35F in the early morning (around 6 AM) and the temperature zooms up to 57F at 11 AM PST.   But then something happens....the temperature rise is stunted and after falling for an hour, it slowly rise to 60F.

What happened?  The sea breeze hit!  Here are the wind speeds at Hoquiam that day.  Around 5 knots in the morning, but then it doubles between 11 AM and noon, staying high until about 4 PM PST.  That strengthening wind is from the sea breeze.

One way to prove this is by looking at wind direction (see below).  Winds were easterly (from land to water) in the morning but then there was an abrupt shift to westerly (onshore) at noon.  The sea breeze.

During warm summer days, a coastal sea breeze is frequent along the Washington coast, resulting in daytime highs often being observed near noon, in contrast to interior locations where the max temps usually occur during the late afternoon.  And we get our own sea breeze around Seattle...the Sound Breeze.  But that is a story for another blog.

During my research for this blog, I learned there is a drink called "the sea breeze", with vodka, cranberry juice, grapefruit juice, and a touch of lime (see below).   Looks really good! There is a related drink, called the "Bay Breeze" that uses pineapple juice instead.  Further  meteorological "research" is needed to determine which is superior.