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!

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