Cheyenne, Wyoming
Regional Weather Alerts
| Alert: | Special Weather Statement |
| Area(s): | Southern Big Horn; Sheridan Foothills |
| Effective: | 2026-09-18 @ 6:04 pm -> 2026-09-18 @ 7:00 pm |
| Onset: | 2026-09-18 @ 6:04 pm |
| Severity: | Moderate |
| Certainty: | Observed |
| Urgency: | Expected |
| Issued By: | NWS Billings MT on 2026-09-18 @ 6:04 pm |
| Headline: | Special Weather Statement issued September 18 at 5:04PM MDT by NWS Billings MT |
| Description: |
At 504 PM MDT, Doppler radar was tracking an area of strong thunderstorms extending from over Ranchester to 29 miles southeast of Sheridan moving northeast at 20 mph. HAZARD...Wind gusts up to 40 mph and penny size hail. SOURCE...Trained Weather Spotters. IMPACT...Gusty winds could knock down tree limbs and blow around unsecured objects. Minor damage to outdoor objects is possible. Locations impacted include... Sheridan, Ranchester, Dayton, Big Horn, Clearmont, Tongue River Reservoir, Banner, Rosebud Battlefield Park and Leiter. |
| Alert: | Special Weather Statement |
| Area(s): | Northeast Johnson County; Southeast Johnson County; Natrona County Lower Elevations |
| Effective: | 2026-09-18 @ 5:57 pm -> 2026-09-18 @ 6:45 pm |
| Onset: | 2026-09-18 @ 5:57 pm |
| Severity: | Moderate |
| Certainty: | Observed |
| Urgency: | Expected |
| Issued By: | NWS Riverton WY on 2026-09-18 @ 5:57 pm |
| Headline: | Special Weather Statement issued September 18 at 4:57PM MDT by NWS Riverton WY |
| Description: |
At 456 PM MDT, Doppler radar was tracking a cluster of strong thunderstorms along a line extending from 17 miles northeast of Mayoworth to near Edgerton. Movement was northeast at 35 mph. HAZARD...Wind gusts of 50 to 55 mph and pea size hail. SOURCE...Radar indicated. IMPACT...Gusty winds could knock down tree limbs and blow around unsecured objects. Minor hail damage to vegetation is possible. Strong thunderstorms will be near... Linch around 500 PM MDT. Fort Reno Historical Site around 505 PM MDT. Other locations in the path of these storms include Powder River Rest Area. This includes the following highways... Interstate 25 between mile markers 256 and 281. Interstate 90 between mile markers 72 and 90. |
| Alert: | Flood Watch |
| Area(s): | Yellowstone National Park |
| Effective: | 2026-09-18 @ 2:10 pm -> 2026-09-19 @ 8:00 am |
| Onset: | 2026-09-18 @ 2:10 pm -> 2026-09-20 @ 7:00 pm |
| Severity: | Severe |
| Certainty: | Possible |
| Urgency: | Future |
| Issued By: | NWS Riverton WY on 2026-09-18 @ 2:10 pm |
| Headline: | Flood Watch issued September 18 at 1:10PM MDT until September 20 at 6:00PM MDT by NWS Riverton WY |
| Description: |
* WHAT...Flash flooding caused by moderate to heavy rainfall is possible, especially in terrain and poor drainage areas. * WHERE...Northwest Wyoming, including Yellowstone National Park. * WHEN...Through Sunday afternoon. * IMPACTS...Heavy rainfall may result in flooding of rivers, creeks, streams, and other low-lying and flood-prone locations. Flooding may occur in poor drainage areas and around steep terrain. * ADDITIONAL DETAILS... - A slow moving weather system will move across Wyoming today through Sunday and bring rounds of showers and thunderstorms to the region, especially northern Wyoming. Any shower or thunderstorm could produce moderate to heavy rainfall across the Watch Area. - http://www.weather.gov/safety/flood |
| Alert: | Flood Watch |
| Area(s): | Absaroka Mountains; Cody Foothills; Owl Creek and Bridger Mountains; Bighorn Mountains West; Bighorn Mountains Southeast; Northeast Johnson County; Southeast Johnson County |
| Effective: | 2026-09-18 @ 2:10 pm -> 2026-09-19 @ 8:00 am |
| Onset: | 2026-09-18 @ 2:10 pm -> 2026-09-20 @ 7:00 pm |
| Severity: | Severe |
| Certainty: | Possible |
| Urgency: | Future |
| Issued By: | NWS Riverton WY on 2026-09-18 @ 2:10 pm |
| Headline: | Flood Watch issued September 18 at 1:10PM MDT until September 20 at 6:00PM MDT by NWS Riverton WY |
| Description: |
* WHAT...Flash flooding caused by moderate to heavy rainfall is possible, especially in terrain and poor drainage areas. * WHERE...Portions of central, north central, and northwest Wyoming, including the following areas, in central Wyoming, Owl Creek and Bridger Mountains. In north central Wyoming, Bighorn Mountains Southeast, Bighorn Mountains West, Northeast Johnson County and Southeast Johnson County. In northwest Wyoming, Absaroka Mountains and Cody Foothills. * WHEN...Through Sunday afternoon. * IMPACTS...Excessive rainfall may result in flooding of rivers, creeks, streams, and other low-lying and flood-prone locations. Flooding may occur in poor drainage and urban areas and around steep terrain. * ADDITIONAL DETAILS... - A slow moving weather system will move across Wyoming today through Sunday and bring rounds of showers and thunderstorms to the region, especially northern Wyoming. Any shower or thunderstorm could produce moderate to heavy rainfall across the Watch Area. - http://www.weather.gov/safety/flood |
| Alert: | Flood Watch |
| Area(s): | Musselshell; Treasure; Northern Rosebud; Northern Stillwater; Powder River; Northern Park; Golden Valley; Red Lodge Foothills; Northern Big Horn; Southern Rosebud; Judith Gap; Paradise Valley; Livingston Area; Beartooth Foothills; Absaroka/Beartooth Mountains; Crazy Mountains; Southern Big Horn; Southeastern Carbon; Northern Sweet Grass; Bighorn Canyon; Northern Carbon; Pryor/Northern Bighorn Mountains; Melville Foothills; Northeastern Yellowstone; Southern Wheatland; Southwestern Yellowstone; Northeast Bighorn Mountains; Sheridan Foothills |
| Effective: | 2026-09-18 @ 12:03 pm -> 2026-09-19 @ 12:15 pm |
| Onset: | 2026-09-18 @ 7:00 pm -> 2026-09-20 @ 7:00 pm |
| Severity: | Severe |
| Certainty: | Possible |
| Urgency: | Future |
| Issued By: | NWS Billings MT on 2026-09-18 @ 12:03 pm |
| Headline: | Flood Watch issued September 18 at 11:03AM MDT until September 20 at 6:00PM MDT by NWS Billings MT |
| Description: |
A strong and slow moving weather system will impact the region tonight through Sunday. Well above normal atmospheric moisture levels combined with the dynamics from this storm system will provide the potential for heavy rainfall during this period. Thunderstorms embedded in the more general rainfall will have the potential to produce flash flooding, particularly over recent burn scars. * WHAT...Flooding caused by excessive rainfall is possible, along with Flash Flooding of recent burn scars. * WHERE...All of South Central Montana, Portions of Southeast Montana, and Sheridan County Wyoming. * WHEN...From 6 PM MDT this evening through Sunday afternoon. * IMPACTS...Excessive runoff may result in flooding of creeks and other low-lying and flood-prone locations. Flooding may occur in poor drainage and urban areas. * ADDITIONAL DETAILS... - 1 to 2.5 inches of rainfall is expected across the watch area tonight through Sunday. Locally heavier totals up to 4 inches are possible where thunderstorm activity is more persistent. - The Robertson Draw, East Side, Elk, and McGhee-Remington burn scars are particularly vulnerable to Flash Flooding and debris flows during the watch period. Any other burn scars from this summer will have elevated Flash Flood potential as well. - http://www.weather.gov/safety/flood |
| Alert: | Hydrologic Outlook |
| Area(s): | Big Horn, WY; Fremont, WY; Hot Springs, WY; Johnson, WY; Lincoln, WY; Natrona, WY; Park, WY; Sublette, WY; Sweetwater, WY; Teton, WY; Washakie, WY |
| Effective: | 2026-09-18 @ 11:20 am -> 2026-09-19 @ 1:00 pm |
| Onset: | 2026-09-18 @ 11:20 am |
| Severity: | Unknown |
| Certainty: | Possible |
| Urgency: | Future |
| Issued By: | NWS Riverton WY on 2026-09-18 @ 11:20 am |
| Headline: | Hydrologic Outlook issued September 18 at 10:20AM MDT by NWS Riverton WY |
| Description: |
ESFRIW A wet weather system will support periods of showers and thunderstorms across Wyoming Friday, Saturday, and Sunday. This weather system is funneling abundant tropical moisture into the state. Given this anomalously high moisture, many thunderstorms will feature heavy rainfall, possibly leading to localized flooding. Poor drainage areas, urban areas, and steep terrain will be the most susceptible locations for this isolated flooding. Many locations could see rainfall totals anywhere between 0.75" to 1.75" through Sunday afternoon, with a majority of this rain falling quickly in thunderstorms. Remember, if you encounter a flooded roadway, turn around don't down! |
