Temperature inversion occurs when temperature increases with altitude.
Today, a superinversion is occurring, with extremely high temperatures aloft.
As of 6 a.m. this morning, temperatures are in the low 50s in the southern Sound and in the upper 50s to around 60s in central Puget Sound (see map). But looking west of the Cascades, you’ll see warmer temperatures with some places in the low 70s.
The weather was so cold in the local river valleys that fog and low clouds formed in some places:
But now, let me surprise you.Just above Puget Sound, just a little over a thousand feet up, it was 80 degrees!
You heard right. In a few hours, the warm air will mix with the surface and high temperatures will rise to the 80s to near 90s in the western lowlands.
The warmest day for the rest of 2024 will occur today
Here is the temperature profile at 6am from aircraft data at SeaTac Airport. About 63F at the surface (452 ft ASL) and 80F at about 1600 ft. UP 17F at about 1000 ft.
Mama Mia…it’s a reversal!
Can you imagine climbing a local peak, like Tiger Mountain, this morning? You’ll go from 55 to 80F in 30 minutes.
The sun will warm the surface today causing increased vertical mixing. Warm air aloft will quickly mix down to the surface and temperatures in the lowlands will spike.
UW’s high-resolution forecast stack (below) shows highs around 90F in SeaTac, then cooling off over the next few days.
And one more thing. Smoke.
The upper-level wind pattern will move some of the smoke from the fires in central Oregon into western Washington. In fact, you can see the smoke in this morning’s visible satellite image:
As the atmosphere mixes vertically today, some of the smoky air will mix downward, primarily over southwest Washington.
Finally, I have some good news to share with you. The National Weather Service has issued a red flag warning for the western slopes of the Cascades (see below).
Fortunately, the chance of a wildfire on the western slope today, and especially a large-scale wildfire, is very low. Why? Because strong easterly winds are not forecast today. Large wildfire events require wind, and wildfires in western Washington require strong easterly winds.
