Saturday, February 2, 2013

A Foul Wind Blows

A remarkably nasty airmass moved into the Salt Lake Valley as cooler, more stable air from over the Great Salt Lake pushed southward this afternoon.  This foul air was clearly visible by eye and appeared to produce an incredible spike in PM2.5 at Hawthorne Elementary School.  Note that the highest PM2.5 values occurred during northwesterly flow, with the airmass much cooler (and more stable) today than the previous afternoon.

The view from my place this evening looked quite sinister as smog and perhaps a bit of fog moved through downtown.  I tried (perhaps unsuccessfully) to take a few photos.

In contrast to the two inversion events in January, this one is warmer.  During the afternoon, it is warmer over the Salt Lake Valley than over the Great Salt Lake (current lake-surface temperature is about -2ÂșC).  As a result, the afternoon lake breeze brings in a stable and apparently more polluted airmass.  Similar effects are seen, for example, in Chicago, due to the influence of Lake Michigan.

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