textproduct: Cheyenne

KEY MESSAGES

- Chances of precipitation increase over the weekend for the mountains, with a few spotty showers possible mainly along and south of the I-80 corridor.

- A more active pattern is expected into the middle of next week, with precipitation chances returning Wednesday into Thursday.

SHORT TERM /THROUGH SUNDAY NIGHT/

Issued at 1226 PM MST Fri Nov 13 2026

One last mild day is expected today before a cooler and more unsettled pattern takes place this weekend. Latest visible satellite trends are showing fog beginning to erode across portions of the Nebraska Panhandle where weak E or SE upslope flow and effective radiative cooling occurred overnight underneath the ridge. These low clouds managed to hang around a bit longer than expected, so decided to nudge down high temperatures for today mainly along the North Platte River Valley (Scottsbluff - Torington) where fog persisted the longest, delaying surface heating. Expect locations across SE Wyoming to experience another day of temperatures 10-15 degrees above average for this time of year, with clouds increasing throughout the day ahead of our next system. Overnight will be similar to last night, with the potential for fog development mainly after 09Z in the moist SE upslope flow regime. Have the highest confidence of widespread and potentially dense fog along the North Platte River Valley which may extend as far west as I-25. Similar to this morning, wouldn't be surprised to see another Dense Fog Advisory be issued by the overnight shift for numerous counties in the Nebraska Panhandle.

Tomorrow will feature cooler temperatures as the ridge axis translates east of our area with rapidly falling 500 mb heights ahead of a negatively-tilted shortwave trough. As this trough is relatively broad with rather weak flow aloft (15-25 knot 500 mb flow), vorticity and hence differential vorticity advection would primarily stem from curvature vorticity (rather than shear vorticity). We also have to consider any forcing for ascent driven by thermal advection/isentropic lift, which also doesn't look favorable over our area as there is actually isentropic descent (cold advection). So, combining the two, since the base of the trough (and hence curvature vorticity) is progged to be well to our south over Colorado and the main forcing being displaced from our region, precipitation chances look to be spotty at best tomorrow evening and overnight into Sunday. The best chances for any beneficial moisture will be along and south of the I-80 corridor, with the most widespread precipitation south of our area in Colorado. Decided to trim PoPs from NBM guidance for this reason, keeping the highest (30-40%) probabilities hugged against the Colorado border. The Sierra Madre and Snowy Mountains across SE Wyoming may manage to pick up an inch or two of snow, but not expecting anything heavy or widespread at this time.

To end the weekend period, shortwave ridging builds in across the Great Basin and Rocky Mountain West which will bring a slight increase in daytime high temperatures on Sunday and drier conditions. Can expect a decrease in clouds and any lingering precipitation throughout the day, resulting in a beautiful afternoon with highs mainly in the 50s to perhaps 60 degrees in a few locations throughout the Nebraska Panhandle. Dry and quiet weather looks to persist into the beginning of the work week.

LONG TERM /MONDAY THROUGH FRIDAY/

Issued at 1226 PM MST Fri Nov 13 2026

Monday...The unusually mild weather continues with broad southwest flow aloft, and high 500 mb heights near 5760 meters overhead. This will induce decent surface lee troughing and mild weather enthusiasts will rejoice with 700 mb temperatures near 6 Celsius and downslope warming boosting maximum temperatures into the mid 50s to mid 60s.

Tuesday...Stronger southwest flow aloft develops across our neck of the woods here in southeast Wyoming and western Nebraska, with a slightly negatively tilted shortwave trough aloft moving across Idaho, Utah and western Wyoming, with surface lee troughing keeping our weather conditions high and dry once again with slightly cooler 700 mb temperatures near 4 Celsius and slightly cooler temperatures for our forecast area, though still on the mild side.

Wednesday...The aforementioned shortwave trough aloft loses amplitude as it moves to eastern Montana and the western Dakotas by sunrise, sending its associated cold front into our counties, Pacific originated. As is typical with these systems, will see scattered to numerous rain and snow showers early in the day west of a Douglas to Laramie line due to dynamics and orographics with some decent snows across our northern Laramie, Snowy and Sierra Madre Ranges, though downslope wind east of the mountains and Laramie Range will as usual provide a rain shadow effect with little if any precipitation east of the Interstate 25 corridor and Laramie Range. Orographic snows will continue in the afternoon for our Snowy and Sierra Madre Ranges, and we may need some type of Winter Weather Highlight such as a Winter Weather Advisory, if model congruency continues.

Thursday...Looks like a windy and relatively mild day for November, the beginning of our typical windy November through March windy season. Strong southwest flow aloft continues, and our wind prone locations such as Arlington, Bordeaux and the Interstate 80 Summit between Laramie and Cheyenne may see some strong winds, and possible wind highlights.

Friday...For climatology enthusiast, November 20th is the latest first measurable snowfall event in recorded history for Cheyenne, with at least one tenth of an inch of snow measured on the ground. Interestingly, this coincides with a decent and progressive neutrally tilted shortwave trough aloft that is progged to move across our forecast area with a rather strong cold frontal passage, which if model timing is correct will produce decent orographic snows for our Laramie, Snowy and Sierra Madre Ranges, and some likely accumulating snow for lower elevations due to the thickness packing along the front, dynamics and synoptic forcing, especially if the track of the system is a bit further south across Colorado, rather than over Wyoming as currently depicted, so please stay tuned to the latest forecasts from your entire National Weather Service team. In any event. Friday the 20th, will be a cold and blustery day with measurable snow becoming increasingly likely at many locations, although snowfall amounts are quite unpredictable for day 7, one week out. Maximum temperatures will only be in the upper 30s to upper 40s with breezy to windy conditions, only six days before Thanksgiving.

AVIATION /00Z TAFS THROUGH 00Z SUNDAY/

Issued at 434 PM MST Fri Nov 13 2026

A mix of mid to high clouds are slowly pushing through the forecast area to give us overcast conditions for almost every terminal. On satellite there is a patch of low clouds around 1,000ft over KAIA. These low clouds are expected to expand across the Panhandle and possibly as far west as KCYS. Expect fog to redevelop overnight around 10z again for the Panhandle. With overcast skies this fog and low clouds may not lift back into VFR conditions until maybe after 21z.

CYS WATCHES/WARNINGS/ADVISORIES

WY...None. NE...None.