Red Flag Warning 13, NWS Riverton, WY

565 
WWUS85 KRIW 061125
RFWRIW

URGENT - FIRE WEATHER MESSAGE
National Weather Service Riverton WY
525 AM MDT Sat Jun 6 2026

WYZ280-070200-
/O.CON.KRIW.FW.W.0013.260606T1700Z-260607T0200Z/
Natrona County/Casper BLM-
525 AM MDT Sat Jun 6 2026

...RED FLAG WARNING REMAINS IN EFFECT FROM 11 AM THIS MORNING TO
8 PM MDT THIS EVENING...

* AFFECTED AREA: 
  In Central WY...Fire Weather Zone 280.

* COUNTIES AFFECTED: 
  In Central WY...Natrona.

* IMPACTS: Low Humidities and Strong Gusty Winds could cause 
  erratic fire behavior. 

* WIND: Southwest 15 to 25 mph with gusts up to 35 mph.

* HUMIDITY: As low as 7 percent.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A Red Flag Warning means that critical fire weather conditions are
either occurring now....or will shortly. A combination of strong
winds...low relative humidity...and warm temperatures can
contribute to extreme fire behavior.

&&

$$

http://weather.gov/riverton

075 
WWUS85 KRIW 061943
RFWRIW

URGENT - FIRE WEATHER MESSAGE
National Weather Service Riverton WY
143 PM MDT Sat Jun 6 2026

WYZ280-071300-
/O.EXT.KRIW.FW.W.0013.000000T0000Z-260608T0200Z/
Natrona County/Casper BLM-
143 PM MDT Sat Jun 6 2026

...RED FLAG WARNING NOW IN EFFECT UNTIL 8 PM MDT SUNDAY...

* AFFECTED AREA: 
  In Central WY...Fire Weather Zone 280.

* COUNTIES AFFECTED: 
  In Central WY...Natrona.

* IMPACTS: Low Humidities...Hot Temperatures...and Strong Gusty 
  Winds could cause erratic fire behavior. 

* WIND: Southwest 20 to 30 mph with gusts up to 45 mph.

* HUMIDITY: As low as 7 percent.

* TEMPERATURES: Highs in the mid to upper 90s.

* ADDITIONAL INFORMATION: Conditions are expected to improve after
  sunset Saturday evening as humidity increases and wind decreases.
  Critical fire weather conditions are again expected by late 
  Sunday morning.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A Red Flag Warning means that critical fire weather conditions are
either occurring now....or will shortly. A combination of strong
winds...low relative humidity...and warm temperatures can
contribute to extreme fire behavior.

&&

$$

http://weather.gov/riverton

361 
WWUS85 KRIW 070523
RFWRIW

URGENT - FIRE WEATHER MESSAGE
National Weather Service Riverton WY
1123 PM MDT Sat Jun 6 2026

WYZ280-080200-
/O.CON.KRIW.FW.W.0013.000000T0000Z-260608T0200Z/
Natrona County/Casper BLM-
1123 PM MDT Sat Jun 6 2026

...RED FLAG WARNING REMAINS IN EFFECT UNTIL 8 PM MDT SUNDAY...

* AFFECTED AREA: 
  In Central WY...Fire Weather Zone 280.

* COUNTIES AFFECTED: 
  In Central WY...Natrona.

* IMPACTS: Low Humidities...Hot Temperatures...and Strong Gusty 
  Winds could cause erratic fire behavior. 

* WIND: Southwest 20 to 30 mph with gusts up to 40 to 50 mph.

* HUMIDITY: As low as 8 to 12 percent.

* TEMPERATURES: Highs in the mid to upper 80s.

* ADDITIONAL INFORMATION: Conditions have improved for the
  overnight hours into Sunday morning as humidity has increased and
  winds decreased. Critical fire weather conditions are again
  expected by late Sunday morning through the afternoon and early
  evening hours through sunset.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A Red Flag Warning means that critical fire weather conditions are
either occurring now....or will shortly. A combination of strong
winds...low relative humidity...and warm temperatures can
contribute to extreme fire behavior.

&&

$$

http://weather.gov/riverton

447 
WWUS85 KRIW 071944
RFWRIW

URGENT - FIRE WEATHER MESSAGE
National Weather Service Riverton WY
144 PM MDT Sun Jun 7 2026

WYZ280-080200-
/O.CON.KRIW.FW.W.0013.000000T0000Z-260608T0200Z/
Natrona County/Casper BLM-
144 PM MDT Sun Jun 7 2026

...RED FLAG WARNING REMAINS IN EFFECT UNTIL 8 PM MDT THIS
EVENING...

* AFFECTED AREA: 
  In Central WY...Fire Weather Zone 280.

* COUNTIES AFFECTED: 
  In Central WY...Natrona.

* IMPACTS: Low Humidities...Hot Temperatures...and Strong Gusty 
  Winds could cause erratic fire behavior. 

* WIND: West 20 to 30 mph with gusts up to 45 mph.

* HUMIDITY: As low as 11 percent.

* TEMPERATURES: Highs in the upper 80s.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A Red Flag Warning means that critical fire weather conditions are
either occurring now....or will shortly. A combination of strong
winds...low relative humidity...and warm temperatures can
contribute to extreme fire behavior.

&&

$$

http://weather.gov/riverton

569 
WWUS85 KRIW 080137
RFWRIW

URGENT - FIRE WEATHER MESSAGE
National Weather Service Riverton WY
737 PM MDT Sun Jun 7 2026

WYZ280-080245-
/O.EXP.KRIW.FW.W.0013.000000T0000Z-260608T0200Z/
Natrona County/Casper BLM-
737 PM MDT Sun Jun 7 2026

...RED FLAG WARNING WILL EXPIRE AT 8 PM MDT THIS EVENING...

Humidity values have risen above critical values this evening.
Thus, the Red Flag Warning will be allowed to expire. 

However, wind gusts of 25 to 45 mph will continue through the next
few hours. Additionally, a cold front will move in from the north 
before midnight, turning winds northerly and keep gusts around 25 
mph continuing through sunrise Monday morning. 

$$

http://weather.gov/riverton

Area Forecast Discussion
National Weather Service Riverton WY
1134 AM MDT Fri Jun 5 2026

.KEY MESSAGES...

- Very warm Friday and Saturday as ridging builds across the
  Rockies. Highs today reach the 80s, with a few low 90s in the
  Bighorn Basin. Temperatures will be even warmer Saturday,
  with highs in 80s and 90s, with a few 100 degree readings
  possible.

- Dry and windy conditions today and tomorrow will lead to
  elevated to near-critical fire weather concerns across the
  state.

- Ridge shifts east next week, bringing better moisture into
  western mountains. Afternoon showers and thunderstorms are
  expected over higher terrain.

&&

.DISCUSSION...
Issued at 224 AM MDT Fri Jun 5 2026

The trough that has been lingering in the vicinity that past
couple days is finally moving to the east, which will open the
door for the next system to impact the NW Rockies. This system
is just starting to drop down the West Coast, and will
gradually buckle a ridge ahead of it across the Rockies during
the next 48 hours. Today will start with flat ridging, with
nearly clear skies and temperatures in the 70s and 80s. West
winds will be lighter than yesterday, but a few gusts near 20
mph are possible across the usual areas of central WY.

The ridge then starts to build in the vicinity tonight into
Saturday, with increasing temperatures aloft. Still noting H7
temps of 16 to 19C, which translates to mid to upper 80s west of
the Divide and into the 90s to the east. There remains an
outside chance of triple digit readings, mainly on the open
ranges of Johnson County and the lowest elevations of the
Bighorn Basin. The placement of the ridge is centered on the
Central Plains, so a weak impulse may nudge into the NW WY Parks
during the afternoon, bringing some cloud cover and a shower or
two, and will hold temps there down in the 70s.

Saturday will also see increasing southwest winds ahead of the
next system. Widespread gusts of 30 to 40 mph are expected
across the state. This southwest flow will also be modified
desert air, so humidity levels will be falling to 5 to 10
percent across a wide swath of the state. These will result in a
near-critical fire weather day across the state.

The ridge shifts to the east Saturday night, shifting the
moisture tap from the southwest across a larger part of western
WY. The first piece of the western trough races across the
state, bringing a good chance for showers and thunderstorms.
The southwest flow will continue into the middle of next week,
which is setting up as a pattern where daytime heating sparks
showers and thunderstorms along the highest terrain in the
afternoon, dissipating each evening.

&&

.AVIATION /18Z TAFS THROUGH 18Z SATURDAY/...
Issued at 1135 AM MDT Fri Jun 5 2026

Upper-level high pressure over Wyoming today has brought very
clear skies with VFR conditions at all TAF sites. Breezy/gusty
southwest winds are expected at most sites this afternoon, with
some gusts reaching 20-25 kts. High-level clouds will move into
western WY between 06/03-06Z this evening and spread eastward
through the night into Saturday morning. They will thicken as a
storm system approaches from the Pacific Northwest on Sunday.
Mid-level clouds are also expected across western and northwest
WY Saturday, but VFR conditions should prevail. As moisture
increases through the day, northwest WY from the Tetons to the
northern Absarokas should see some light showers Saturday
evening. Southwest surface winds will increase by 06/17Z and
increase by 06/19Z to 10-20 kts with 20-30 kt gusts at nearly
all TAF sites.

Please see the Aviation Weather Center and/or CWSU ZDV and ZLC for
the latest information on icing and turbulence forecasts.

&&

.RIW WATCHES/WARNINGS/ADVISORIES...
Fire Weather Watch from Saturday morning through Saturday
evening for WYZ280.

&&

DISCUSSION...Straub
AVIATION...McDonald