Today was the warmest day of the year so far, with some western Washington locations reaching the mid-80s, bringing some strange and remarkable weather features to our area.
First, there were some dramatic mirages for locations near Puget Sound. Sandy beaches became sand cliffs, mountains were thrust high with strange valleys, and houses were displaced into the sky (see sample below off of Whidbey Island)
Picture courtesy of Greg Johnson
So what is going on?
Superior mirages produced by the intense inversion (temperature warming with height) in the lowest few hundred feet of the atmosphere.
Why such a strong inversion? Because we had very warm air above our cold (about 50F) water.
To illustrate, below is the temperature variation with height (red line shows temperature) at Forks, near the NW Washington Coast. Temperature is in C (x-axis), and height is in pressure ( hPa, 850 is about 5000 ft).
An intense 15 °C low-level inversion (again, temperature warming with height) near the surface.
Such inversions act as a lens that bends light, making objects look higher than they really are. Superior in this case means higher.
But not only did we have crazy optical effects, but we had a super sea breeze on the coasts.
So strong that its leading edge was apparent in the weather radar around 1 PM today (dark blue line):
At Hoquium, near the Washington Coast, the sea breeze front produced a rapid wind shift from easterly to northwesterly around 1 PM, accompanied by a substantial acceleration of the wind speed.
Temperature peaked around 80°F before the sea breeze hit, and then dropped into the 60s by late afternoon.
Our short heatwave is over, and western Washington should remain below 70F for the next week. Plus, lots of rain over the weekend.