


Area Forecast Discussion
Issued by NWS Cheyenne, WY
Issued by NWS Cheyenne, WY
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061 FXUS65 KCYS 140455 AFDCYS Area Forecast Discussion National Weather Service Cheyenne WY 1055 PM MDT Mon Oct 13 2025 .KEY MESSAGES... - Gusty southerly winds will continue through this evening along with chances of scattered rain showers. - Areas of locally dense fog may develop late tonight into tomorrow morning near the I-80 summit and over the High Plains. - Another storm system will slowly move through the area late Wednesday through early Friday, bringing first showers and thunderstorms, following by chances of mountain snow and strong winds. && .SHORT TERM /THROUGH TUESDAY NIGHT/... Issued at 222 PM MDT Mon Oct 13 2025 Clouds are moving into the CWA and expect them to linger through the overnight hours while rain showers are not too far behind. Why did we cloud up today along with increased chances of rain showers, well, a strong conveyor of monsoonal moisture is being pumped into our CWA. This is due to a deep upper level trough diving south into the California Coast and ridging amplifying to our east, which is bringing southwest flow to our area. Instability parameters are meager at best so thunderstorms are unlikely, but can`t be totally ruled out, especially in Carbon County where the best instability exists. All this activity should end tonight, say about 9PM, with more energy moving in late tonight through Tuesday afternoon. Carbon County may not catch a break from precipitation as hi-res guidance indicates, this along with a few other locations west of I-25. Winds are the other big story as a tight pressure gradient has set up over our CWA, producing strong southerly to southeasterly winds which may gust in the 30 to 45 mph range. Laramie, being the exception, may see gusts topping out to near 50 mph. The gradient laxes a bit overnight; however, winds only weaken slightly. As mentioned above, the southwest flow will also result in higher dewpoint values which will help with fog developing late tonight into tomorrow morning, especially over the I-80 summit and portions of southeast Wyoming and the Nebraska Panhandle. Expect more fog to develop Tuesday night into Wednesday morning, which could be more widespread. Highs today generally in the upper 50s to low 60s with slightly warmer temps for Tuesday, while lows won`t dip down as low as we`ve seen over the previous nights. && .LONG TERM /WEDNESDAY THROUGH MONDAY/... Issued at 222 PM MDT Mon Oct 13 2025 At the start of the long term, a pretty robust 500mb trough is deep across the Western CONUS while ridging sits to our east over the Central Plains. As we progress through the long term period, the upper level trough will slide east into our CWA by Thursday evening, continuing on a easterly track through the weekend. So, what does all this mean for us, well, expect an active pattern through mid-week with southwest flow pumping in deep moisture. As the 500mb trough slips to our east by the weekend, upper level flow will then become northwesterly. This will bring in some changes, especially to the temperatures. Initially, with the southwest flow, temperatures will warm through Wednesday with highs approaching 5 to 15 degrees above normal. The warmest temperatures for this short period will be across the Nebraska Panhandle as highs top out in the low to mid 70s, with a few locations possibly hitting 80 degrees F. Lets go down to 700mb where we see temps hitting 6 to 10 degrees C, this along with clear skies will help achieve the temps mentioned previously. All this will be short lived though, because we will see increasing clouds and precipitation chances late Wednesday into Thursday. As the 500 mb trough pushes east of our CWA, a cold front will move through Thursday resulting in a return of cooler temps. This too will be aided by the upper level pattern as flow aloft becomes northwesterly. Expect cooler temperatures Friday into the weekend. Also, as the cold front passes, another high wind event may be possible Thursday into Friday. At the tail end of the long term period, expect the coldest temps over the weekend while moderating some on Monday as ridging aloft builds in. && .AVIATION /06Z TAFS THROUGH 06Z WEDNESDAY/... Issued at 1054 PM MDT Mon Oct 13 2025 A few scattered light rain showers will linger overnight along with gusty winds. Another round of precipitation will arrive early Tuesday morning, bringing low stratus to areas east of the Laramie Range. Low stratus will lead to MVFR and/or IFR CIGs through the morning hours. Visibility reductions due to fog also cannot be ruled out around KCYS Tuesday morning. Minor visibility reduction may also be possible in showers. && .CYS WATCHES/WARNINGS/ADVISORIES... WY...None. NE...None. && $$ SHORT TERM...RZ LONG TERM...RZ AVIATION...SF