307 FXUS65 KCYS 162232 AFDCYS Area Forecast Discussion National Weather Service Cheyenne WY 432 PM MDT Sun Oct 16 2022 .SHORT TERM...(Late this afternoon through Tuesday night) Issued at 225 PM MDT Sun Oct 16 2022 No changes in the large scale pattern this afternoon with the nearly stationary broad upper trough over the eastern CONUS and upper ridge over the Intermountain West. A dry northerly flow aloft prevailed with mostly sunny to sunny skies. Temperatures ranged from the upper 40s to lower 60s. Winds were north to northeast 5-15 kt with gusts to near 25 kt in the southeast WY wind-prone zones. Northerly to northwesterly flow aloft will persist with little change in the synoptic scale pattern during the short term. There will be no moisture to work with, so nil PoPs. Light winds, a dry boundary layer and clear skies will promote ideal radiational cooling with freezing temperatures and areas of frost over much of southeast WY. Temperatures will moderate Monday with highs in the lower to mid 60s. Nearly identical conditions forecast Monday night and early Tuesday morning with 20s and lower 30s. The warming trend continues Tuesday with 700mb temperatures rising to 4C to 6C in the afternoon. Expect highs in the 60s to near 70F. Winds will remain relatively light Tuesday. .LONG TERM...(Wednesday through Sunday) Issued at 225 PM MDT Sun Oct 16 2022 Long term forecast remains on track with little changes in the Wednesday to Friday timeframe. Quiet but breezy weather expected for the latter half of the work week as an upper-level ridge sits just to the west of the Rockies. This will result in dry conditions with above average high temperatures through at least Friday. Mid 60s are expected for areas west of the Laramie Range. Areas to the east will see temperatures in the mid 60s to mid 70s, which is about 5 to 10 degrees above average. More forecast uncertainty is expected for the weekend. Both the 12Z deterministic GFS and ECMWF model runs seem to have shifted the timing of the front later than previous runs. Cold front looks to move through during the day on Sunday rather than Saturday night. The GFS also looks much wetter than previous runs which could lead to a pretty solid snowfall event for the Snowy and Sierra Madre Ranges. As for the lower elevations, precipitation type will likely be dependent on the time of day. Long range ensembles still show somewhat mild daytime temperatures, but nighttime lows will likely fall below freezing Sunday night for most locations. Lastly, cannot rule out the potential for a high wind event Friday night into Saturday out ahead of the cold front. Looks like our typical cold season high wind set up with tightening pressure and height gradients ahead of a strong cold front. Winds aloft at 750 mb reach 55 to 60 kts with good subsidence to bring them down to the surface. If the front weakens, the potential for high winds may decrease, but for now, upped the winds slightly Saturday. && .AVIATION...(For the 00Z TAFS through 00Z Monday evening) Issued at 429 PM MDT Sun Oct 16 2022 Pretty tranquil conditions next 24 hours with clear skies and light winds. West winds returning Monday as a weak cold front edges east. No weather impacts expected for next 24 to 48 hours. && .FIRE WEATHER... Issued at 225 PM MDT Sun Oct 16 2022 A dry northwesterly flow aloft will prevail through the week. Temperatures will warm each day to above seasonal normals. No fire weather concerns are anticipated through Tuesday with relatively light winds. Gusty winds and afternoon relative humidities decreasing to 10 to 15 percent will raise concerns with potential Red Flag conditions Wednesday through Friday for much of the region. A trend toward cooler and wetter weather returns next weekend. && .CYS WATCHES/WARNINGS/ADVISORIES... WY...None. NE...None. && $$ SHORT TERM...MAJ LONG TERM...SF AVIATION...GCC FIRE WEATHER...MAJ