Area Forecast Discussion
Issued by NWS Cheyenne, WY
Issued by NWS Cheyenne, WY
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072 FXUS65 KCYS 010836 AFDCYS Area Forecast Discussion National Weather Service Cheyenne WY 236 AM MDT Thu Oct 1 2026 .KEY MESSAGES... - Warmer temperatures and drier conditions will continue into the weekend. && .SHORT TERM /THROUGH FRIDAY NIGHT/... Issued at 235 AM MDT Thu Oct 1 2026 Not much to speak of in the short term as benign weather is expected through the end of the work week. Cloud cover will gradually decrease throughout the morning on Thursday as the low pressure system over Kansas continues to move eastward. Upper-level ridging over southern California will also gradually shift eastward into the Four Corners region, helping to move clouds out of the area. Temperatures will be roughly the same as yesterday with highs mainly in the 60s to low 70s. Today will mark the start of a drying trend with the strengthening ridge keeping precipitation chances at bay. Heading into the overnight hours, a low-level jet will develop over the eastern half of the forecast area, leading to breezy conditions. Breezy conditions will continue into the day Friday as flow aloft becomes more zonal. Zonal flow will lead to downslope, helping warm temperatures across the area. Zonal flow will also help usher in warmer and drier air aloft. High temperatures on Friday will be anywhere from 5 to 15 degrees warmer than Thursday. These temperatures will be about 10 degrees above average for the beginning of October. On top of the warming temperatures, conditions will get drier with mostly sunny skies and no precipitation chances anticipated. Overnight lows Friday night will also be on the milder side. && .LONG TERM /SATURDAY THROUGH WEDNESDAY/... Issued at 151 PM MDT Wed Sep 30 2026 Global ensemble forecast guidance remains generally unchanged compared to yesterday regarding the long-term forecast period from this weekend into next week. High confidence exists for tranquil weather through much of the long-term period. Large-scale ridging will dominate the weather pattern over the western CONUS resulting in generally mild above-average temperatures and limited precipitation chances over southeast Wyoming and western Nebraska. This ridging pattern continues to be a result of the highly active tropical pattern over the eastern Pacific. Numerous EPAC and CPAC tropical storms will continue to move west and then recurve to the north in the mid-latitudes of the central Pacific, resulting in potent synoptic troughing over the Bearing Sea/Gulf of Alaska. This setup then drives downstream ridging over western North America, which is apparent once again in today`s ensemble mean guidance. As mentioned yesterday, these types of stable-synoptic-wave patterns can often persist for weeks or more, locking in high-confidence forecasts over much of the west including our region. Local details remain largely unchanged in the forecast. Above- average temps are expected each day from Saturday onward. High confidence exists in temps around 5 degrees above average this weekend (low to mid-70s east of the mountains) and highs 10 to 15 degrees above average through next week. The one new exception in the forecast in today`s guidance is a very weak wave in the overall ridge which may move through on Tuesday. Ensemble guidance has a very high amount of spatiotemporal dispersion with regard to this system. Some members do not even show this wave, and others bring it through strong enough to produce some weak showers over the higher terrain of southern Wyoming and northern Colorado. We will opt for the driest solutions for now given recent model performance with similar systems. Mild temps even during the overnight hours should continue to hold off the first frosts for any populated areas outside of the mountains. Afternoon RH values will drop to near or slightly below 20% throughout the weekend during the afternoon hours across all of southeast Wyoming and portions of the Nebraska panhandle. However, generally light surface flow out of the west less than 20 mph will likely preclude the need for any fire weather headlines. The synoptic pattern described in both today`s and yesterdays discussion will continue to result in high forecast confidence throughout the entire long-term period with limited societal impacts expected. && .AVIATION /06Z TAFS THROUGH 06Z FRIDAY/... Issued at 1122 PM MDT Wed Sep 30 2026 High level clouds continue to move through portions of the CWA as a robust storm tracks across the Central Plains. Chances of precipitation remains nil as the bulk of the shower activity will stay to our south and east. So, expect VFR conditions to prevail across all terminals for the duration of this TAF period. No other aviation weather concerns for this forecast period as winds overnight into Thursday will be generally less than 15 knots. && .CYS WATCHES/WARNINGS/ADVISORIES... WY...None. NE...None. && $$ SHORT TERM...SF LONG TERM...MAC AVIATION...RZ