Signs of Change

Signs of change were quite apparent when I exited the house to head to campus this morning.  Lake stink, smoky air, and a light northwest wind were all evidence of an overnight airmass change.

MesoWest observations indeed show that a surface trough pushed through northern Utah and at 0730 MDT was draped across the southern Salt Lake Valley.  Strong northerly winds were evident over the Great Salt Lake and Desert.

Source: MesoWest

There's not much of a temperature contrast across the trough, but it does mark the leading edge of cooler air over the northwest.

The 1200 UTC HRRR calls for the front to linger around southern Salt Lake County and northern Utah County through about 1800 UTC (1200 MDT).

After that, it finally pushes southward as the main upper-level wave migrates eastward.

And speaking of that wave, it's producing about the most organized "s-shaped" cirrostratus deck we've seen around here in months.  Check it out to our west this morning, accompanied by a band of precipitation.

That feature may give us some scattered showers and thunderstorms tonight.  No guarantees of precipitation at your place, but some might get it.

Then there's the forecast for tomorrow.  Post trough, tomorrow dawns with 700-mb temperatures around +7ºC, probably the coldest airmass we've seen around here since mid June.

Bring a jacket tomorrow if you're riding the crest trail.