National Weather Service Cheyenne, WY

Cheyenne is the largest city in Wyoming with a population of about 65,000 people in city limits and 100,000 people in Laramie County. WFO Cheyenne is located just across the street from the Cheyenne Airport and is fairly centrally located in town. While Cheyenne has a small town atmosphere, we are just 50 miles from Fort Collins, CO (population: ~170,000), and 100 miles from Denver, CO (metro population: ~3 million), giving easy access to big city amenities.

The CYS Forecast area is a very diverse landscape covering 35,641 square miles and about 265,000 people ranging from the windswept summit of Medicine Bow Peak at 12,013' to the White River's meandering crossing from Nebraska into South Dakota at about 3,000'. Cheyenne sits at 6,086' (the second highest elevation WFO!) right at the western edge of the High Plains before climbing into the rugged Rocky Mountains. While the population is small, we cover two critical transportation corridors: Interstate 80 and Interstate 25.

We pride ourselves on supporting our employees to achieve a diverse set of career goals. Research and innovation is actively encouraged, along with personal and professional development. We also support strong collaborative relationships both within the office and with our external partners. Former CYS employees have advanced far and wide across the NWS! The map to the right shows the locations where CYS employees have worked before (brown) or after (yellow) their time in Cheyenne.

Cheyenne can experience its fair share of extreme cold, but thanks to the moderating influence of the Chinook winds, it usually doesn't last too long. We average 8 days per year with a low temperature below 0F, and 33 days per year with a maximum temperature below freezing. This is more moderate than a lot of our counterparts on the plains! In fact, we also average 20 days in December-February that warm to 50F or above. The sunny climate also helps avoid the blues of winter felt in other parts of the country.

Cheyenne has a fairly dry climate, with just 15.37" of precipitation per year. The winter is relatively dry, and almost all precipitation falls as snow from November through March. Our wet season is typically April through June which leads to a green-up of the High Plains before things dry out in the late summer and fall. We are at the very periphery of the influence of the North American Monsoon, so we can still expect regular thunderstorm activity through July and August.

There is one part of Cheyenne's climate that we can all agree we don't like - the infamous wind. Southern Wyoming is one of the windiest places in the United States. Cheyenne averages 25 days per year with a wind gust over 50 MPH, mainly during the November-April windy season. Our highest wind gust ever recorded was 89 MPH in January 2021.

We average 62.3" of snow per year in town. The average first snowfall is October 5, and the average last snowfall is May 15. However, snow has been recorded as early as September 8 (2020) and as late as June 12 (1947). While our snow potential season is extremely long, it is rare for snow to stick around very long. We average 43 days per year with 1" or greater snow depth. Most of our snow falls in frequent small to moderate events, but occasionally we can get very large blizzards with 12+" of snow, mainly in the shoulder seasons of Late October through early December, or Late February through April.

Winter products can be issued from September through June, thanks to our high mountain peaks that can get an estimated 400"+ of snow per year. The complex terrain often requires the local expertise of NWS Cheyenne meteorologists in understanding model biases in order to accurately forecast winter events. But it's not just mountain snow here! From blizzards to snow squalls to arctic cold fronts and everything in between, no two winter events are the same around here. We also work regularly with WYDOT and NEDOT to keep travelers safe along the busy Interstate 80 corridor, over the two mountain passes, and open plains.

While high winds are not unique to CYS, we get the most experience with them. We issue by far the most High Wind Warnings of any WFO in the country, thanks to the gap in the Rocky Mountains in southern Wyoming. In addition to the large scale gap, local scale gaps in terrain lead to a few particularly wind prone areas along both Interstate 80 and Interstate 25. Every NWS Cheyenne meteorologist will very quickly become a high wind expert!

By May high wind and winter weather, transition to the severe weather season. The Front Range and High Plains is a hot spot for hail, leading to the area around Wyoming, Nebraska, and Colorado to be nicknamed "Hail Alley". Storms can produce anything from giant destructive hail to plowable amounts of small to medium sized hail. Severe wind threats from squall lines to dry microbursts to even one case of a derecho on June 6, 2020 are all part of the ensemble of severe weather challenges in our area. Typical high plains supercells are of the low-precipitation variety, which can lead to stellar storm photography in and around Cheyenne. While strong to violent tornadoes are rare here, a few events per year can include a tornado or landspout threat for the area. Those interested in severe weather forecasting will not be bored here!

Fire season is usually bimodal in our area. The first is grass fire season generally over the High Plains in March and April before the green up begins. The second is in the summer through early fall, once the snow melts in the mountains and the grasses dry out in the plains. We have excellent relationships with our fire partners in both Wyoming and Nebraska. The varied terrain and flora across our area is sure to refine your fire weather forecasting skills.

While we do have a short river flood season during spring runoff from the mountains (typically May-June), the main hydrological challenges here come from thunderstorm induced flash flooding and burn-scar flash flooding. Thanks to the 2020 Mullen Fire which burnt over 175,000 acres of the Medicine Bow Mountains, there are ongoing issues with flash flooding and mudslides in the sensitive ecology left behind. Constant situational awareness and quick thinking are essential to successful hydrological forecasts and warnings here!

In addition to working with transportation, fire, and air quality partners in two states, CYS offers quite a few DSS opportunities for those wishing to improve their skills in partner relations and communications. The biggest event of the year is Cheyenne Frontier Days, where NWS Cheyenne typically sends 1-2 meteorologists for onsite support each day through the 10-day event which can have tens of thousands of outdoor attendees on busy concert nights. We also frequently conduct community outreach at schools, transportation departments, fire departments, and for the public through spotter talks and specialized training sessions. There are numerous other opportunities for forecasters to enhance their DSS experience.

While the Cheyenne forecast area does not include any major airports, our 7 TAF sites at small airports offer a diverse set of forecast challenges. From snow squalls to microbursts, to valley fog in Laramie or low clouds encroaching up the terrain from the east, the aviation forecast is rarely quiet here. Occasionally we have also had opportunities to forecast for specialized aviation events such as air shows and National Guard exercises! Our proximity to F.E. Warren Air Force Base and the Wyoming National Guard allows for meteorologists to work closely with these external aviation partners.