The National Weather Service in Cheyenne has issued a Freezing Fog Advisory, which is in effect until 6:00 AM Thursday (November 7). The advisory includes the Interstate-80 corridor from Cheyenne to eastern Albany Country and the I-25 corridor north of Cheyenne to near Wheatland.

"Areas of dense freezing fog are expected overnight, with visibilities at or below one-quarter of a mile."

URGENT - WEATHER MESSAGE
National Weather Service Cheyenne WY
254 PM MST Wed Nov 6 2019

...Freezing Fog Advisory Tonight...

.Areas of dense freezing fog are expected overnight, with
visibilities at or below one-quarter of a mile.

WYZ106-116>118-071300-
/O.NEW.KCYS.ZF.Y.0005.191107T0100Z-191107T1300Z/
Central Laramie Range and Southwest Platte County-
South Laramie Range-South Laramie Range Foothills-
Central Laramie County-
Including the cities of Bordeaux, Buford, Pumpkin Vine, Vedauwoo,
Whitaker, Federal, Horse Creek, and Cheyenne
254 PM MST Wed Nov 6 2019

...FREEZING FOG ADVISORY IN EFFECT FROM 6 PM THIS EVENING TO 6 AM
MST THURSDAY...

The National Weather Service in Cheyenne has issued a Freezing
Fog Advisory, which is in effect from 6 PM this evening to 6 AM
MST Thursday.

* TIMING...6 PM to 6 AM.

* VISIBILITY...One-quarter of a mile or less.

* IMPACTS...Visibilities will be reduced to one-quarter of a mile
  or less. Also expect areas of freezing drizzle and light snow,
  along with icy and slick roads in spots.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A Freezing Fog Advisory means visibilities will frequently be
reduced to less than one quarter mile. If driving...slow down...
use your headlights...and leave plenty of distance ahead of you.
Also...be alert for frost on bridge decks causing slippery roads.