Areas of freezing fog with cold temperatures this week 

Patchy fog after 10pm for areas of the Snake River Plain. Otherwise, increasing clouds, with a low around 8°. Light winds at 5 mph from the north.

Patchy fog before 8am for Tuesday. Otherwise, mostly sunny, with a high temperature in the lower 30’s. North winds around 5 to 10 mph. More areas of freezing for Tuesday night, with a low around 10°.

Wednesday, chance of AM fog, with Partly sunny skies in the afternoon. A high near 32°.

AIR STAGNATION ADVISORY IN EFFECT UNTIL NOON MST THURSDAY:

• WHAT…An extended period of stagnant air, with light winds
  and little vertical mixing, is expected.
• WHERE…The entire Snake River plain, including the Arco-Mud
  Lake region, the Wood River foothills, the Big and Little Lost
  River Valleys, the Bear Lake Valley, and Teton Valley. This
  includes Idaho National Laboratory, Fort Hall, Craters of the
  Moon, and the cities and towns of American Falls, Pocatello,
  Blackfoot, Shelley, Idaho Falls, Rexburg, Rockland, Montepelier,
  Ashton, Driggs, Howe, Mackay, Hailey and Bellevue.
• WHEN…Until noon MST Thursday.
• IMPACTS…Periods of air stagnation can lead to the buildup of
  pollutants near the surface. Should air quality deteriorate to
  health-impacting levels, an Air Quality Advisory will be issued.

PRECAUTIONARY/PREPAREDNESS ACTIONS…

If possible, reduce or eliminate activities that contribute to
air pollution, such as outdoor burning, and the use of
residential wood burning devices. Reduce vehicle trips and
vehicle idling as much as possible. Check with local agencies
for possible restrictions in your area.