Alert archive / Wyoming / Red Flag Warnings in 2021

Red Flag Warning 12, NWS Riverton, WY

August 16, 20214 counties in Wyoming

NWS Riverton, WY issued this red flag warning at Aug 16, 2021, 2:24 AM MDT for 4 counties in Wyoming. It took effect at Aug 16, 2021, 2:00 PM MDT. It was in force for 7 hr. No storm report in the archive falls inside the area while it was in force.

The area

The counties it named.

The facts

Issued: Aug 16, 2021, 2:24 AM MDT (08:24 UTC)
In effect from: Aug 16, 2021, 2:00 PM MDT
Expired: Aug 16, 2021, 9:00 PM MDT
In force: 7 hr
Issued by: NWS Riverton, WY

Counties Fremont County, WY, Hot Springs County, WY, Park County, WY, Teton County, WY

The radar

The Riverton/Lander radar (KRIW), 106 km from the middle of the area, began a volume at 08:26 UTC, the scan nearest the moment this went out.

Open the radar archive at this moment

The archived warnings, watches and discussions in force at that minute are drawn over the scan, this one among them.

The nearest sounding before it

Riverton, WY (KRIW), launched 00:00Z, 8.4 hours before the alert went out and 110 km from the middle of its area. This is the routine balloon launch nearest before it, the air the forecaster had in hand, not a measurement taken for the alert.

Skew-T log-p

Temperature in red, dew point in green, the mixed-layer parcel dashed.

Hodograph

The wind turning with height, colored by layer: ground to 1 km, 1 to 3 km, 3 to 6 km, 6 to 10 km.

Mixed-layer CAPE: 32 J/kg
Mixed-layer CIN: -116 J/kg
Mixed-layer LCL: 3327 m above ground
0-6 km bulk shear: 9 kt
0-1 km storm-relative helicity: 1 m²/s²
0-3 km storm-relative helicity: 30 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

The text

As transmitted.

514 
WWUS85 KRIW 160824
RFWRIW

URGENT - FIRE WEATHER MESSAGE
National Weather Service Riverton WY
224 AM MDT Mon Aug 16 2021

WYZ140-286-162200-
/O.NEW.KRIW.FW.W.0012.210816T2000Z-210817T0300Z/
Yellowstone National Park-Absaroka Mountains/North Shoshone NF-
224 AM MDT Mon Aug 16 2021

...RED FLAG WARNING IN EFFECT FROM 2 PM THIS AFTERNOON TO 9 PM MDT
THIS EVENING...

The National Weather Service in Riverton has issued a Red Flag
Warning, which is in effect from 2 PM this afternoon to 9 PM MDT
this evening.

* IMPACTS: Low Humidities...Hot Temperatures...Strong Gusty
  Winds...and Isolated Dry Thunderstorms with gusty and erratic
  outflow winds will create erratic fire behavior and possibly new
  fire starts. 

* AFFECTED AREA: 
  In Northwest WY...Fire Weather Zones 140 and 286.

* COUNTIES AFFECTED: 
  In Central WY...Fremont.
  In North Central WY...Hot Springs...Park.
  In Northwest WY...Yellowstone National Park.

* WIND: West 10 to 20 mph with gusts up to 30 mph.

* THUNDERSTORMS: Isolated dry thunderstorms.

* HUMIDITY: As low as 14 percent.

* TEMPERATURES: Highs in the lower 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.

&&

$$

WYZ277>279-162200-
/O.NEW.KRIW.FW.A.0006.210817T1800Z-210818T0300Z/
Lincoln and Uinta Counties/Lower Elevations-
Upper Green River Basin/Rock Springs BLM-
Sweetwater County/Rock Springs BLM/Flaming Gorge NRA-
224 AM MDT Mon Aug 16 2021

...FIRE WEATHER WATCH IN EFFECT FROM TUESDAY AFTERNOON THROUGH
TUESDAY EVENING...

The National Weather Service in Riverton has issued a Fire Weather
Watch, which is in effect from Tuesday afternoon through Tuesday
evening.

* IMPACTS: Low Humidities...Hot Temperatures...Strong Gusty
  Winds...will create erratic fire behavior with any existing or 
  new fires. 

* AFFECTED AREA: 
  In Southwest WY Fire Zones...277...279.
  In West Central WY Fire Zone....278.

* COUNTIES AFFECTED: 
  In Southwest WY...Sweetwater...Uinta.
  In West Central WY...Lincoln...Sublette.

* WIND: Southwest 10 to 20 mph with gusts up to 35 mph.

* HUMIDITY: As low as 12 percent.

* TEMPERATURES: Highs in the upper 80s.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A Fire Weather Watch means that critical fire weather conditions
are forecast to occur. Listen for later forecasts and possible Red
Flag Warnings.

&&

$$

WYZ283-288-162200-
/O.NEW.KRIW.FW.A.0006.210817T1800Z-210818T0300Z/
Upper Wind River Basin/Wind River Basin-
East Wind River Mountains/South Shoshone NF-
224 AM MDT Mon Aug 16 2021

...FIRE WEATHER WATCH IN EFFECT FROM TUESDAY AFTERNOON THROUGH
TUESDAY EVENING...

The National Weather Service in Riverton has issued a Fire Weather
Watch, which is in effect from Tuesday afternoon through Tuesday
evening.

* IMPACTS: Low Humidities...Hot Temperatures...Strong Gusty
  Winds...will create erratic fire behavior with any existing or 
  new fires.  

* AFFECTED AREA: 
  In Central WY...Fire Weather Zones 283 and 288.

* COUNTIES AFFECTED: 
  In Central WY...Fremont.
  In West Central WY...Sublette.

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

* HUMIDITY: As low as 11 percent.

* TEMPERATURES: Highs in the upper 80s.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A Fire Weather Watch means that critical fire weather conditions
are forecast to occur. Listen for later forecasts and possible Red
Flag Warnings.

&&

$$

WYZ282-285-287-162200-
/O.NEW.KRIW.FW.A.0006.210817T1800Z-210818T0300Z/
South Big Horn Basin/Worland BLM-South Bighorn Mountains-
Owl Creek Mountains-
224 AM MDT Mon Aug 16 2021

...FIRE WEATHER WATCH IN EFFECT FROM TUESDAY AFTERNOON THROUGH
TUESDAY EVENING...

The National Weather Service in Riverton has issued a Fire Weather
Watch, which is in effect from Tuesday afternoon through Tuesday
evening.

* IMPACTS: Low Humidities...Hot Temperatures...Strong Gusty
  Winds...will create erratic fire behavior with any existing or 
  new fires. 

* AFFECTED AREA: 
  In Central WY Fire Zone....285.
  In North Central WY Fire Zones...282...287.

* COUNTIES AFFECTED: 
  In Central WY...Fremont...Natrona.
  In North Central WY...Hot Springs...Johnson...Washakie.

* WIND: Southwest 10 to 20 mph with gusts up to 30 mph.

* HUMIDITY: As low as 11 percent.

* TEMPERATURES: Highs in the lower 90s.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A Fire Weather Watch means that critical fire weather conditions
are forecast to occur. Listen for later forecasts and possible Red
Flag Warnings.

&&

$$

WYZ280-289-300-162200-
/O.NEW.KRIW.FW.A.0006.210817T1800Z-210818T0300Z/
Natrona County/Casper BLM-
Granite/Green/Ferris/Rattlesnake Mountains-Casper Mountain-
224 AM MDT Mon Aug 16 2021

...FIRE WEATHER WATCH IN EFFECT FROM TUESDAY AFTERNOON THROUGH
TUESDAY EVENING...

The National Weather Service in Riverton has issued a Fire Weather
Watch, which is in effect from Tuesday afternoon through Tuesday
evening.

* IMPACTS: Low Humidities...Hot Temperatures...Strong Gusty
  Winds...will create erratic fire behavior with any existing or 
  new fires. 

* AFFECTED AREA: 
  In Central WY...Fire Weather Zones 280...289 and 300.

* COUNTIES AFFECTED: 
  In Central WY...Fremont...Natrona.
  In Southwest WY...Sweetwater.

* WIND: Southwest 10 to 20 mph with gusts up to 30 mph.

* HUMIDITY: As low as 11 percent.

* TEMPERATURES: Highs in the lower 90s.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A Fire Weather Watch means that critical fire weather conditions
are forecast to occur. Listen for later forecasts and possible Red
Flag Warnings.

&&

$$

21

2 follow-up statements

790 
WWUS85 KRIW 161950
RFWRIW

URGENT - FIRE WEATHER MESSAGE
National Weather Service Riverton WY
150 PM MDT Mon Aug 16 2021

WYZ277>279-170800-
/O.UPG.KRIW.FW.A.0006.210817T1800Z-210818T0300Z/
/O.NEW.KRIW.FW.W.0013.210817T1800Z-210818T0300Z/
Lincoln and Uinta Counties/Lower Elevations-
Upper Green River Basin/Rock Springs BLM-
Sweetwater County/Rock Springs BLM/Flaming Gorge NRA-
150 PM MDT Mon Aug 16 2021

...RED FLAG WARNING IN EFFECT FROM NOON TO 9 PM MDT TUESDAY...

The National Weather Service in Riverton has issued a Red Flag
Warning, which is in effect from noon to 9 PM MDT Tuesday. the
Fire Weather Watch is no longer in effect.

* IMPACTS: Low Humidities...Hot Temperatures...Strong Gusty 
  Winds...and Dry Thunderstorms with gusty and erratic outflow 
  winds will create erratic fire behavior and new fire starts. 

* AFFECTED AREA: 
  In Southwest WY Fire Zones...277...279.
  In West Central WY Fire Zone....278.

* COUNTIES AFFECTED: 
  In Southwest WY...Sweetwater...Uinta.
  In West Central WY...Lincoln...Sublette.

* WIND: Southwest 10 to 20 mph with gusts up to 35 mph.

* HUMIDITY: 12 to 16 percent.

* TEMPERATURES: Highs in the middle 80s to near 90 degrees.

* THUNDERSTORMS: Isolated to scattered virga showers and dry
  thunderstorms will develop over zones 277, 278 and the western
  half of 279. Showers will remain possible Tuesday night. 

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.

&&

$$

WYZ283-288-170800-
/O.UPG.KRIW.FW.A.0006.210817T1800Z-210818T0300Z/
/O.NEW.KRIW.FW.W.0013.210817T1800Z-210818T0300Z/
Upper Wind River Basin/Wind River Basin-
East Wind River Mountains/South Shoshone NF-
150 PM MDT Mon Aug 16 2021

...RED FLAG WARNING IN EFFECT FROM NOON TO 9 PM MDT TUESDAY...

The National Weather Service in Riverton has issued a Red Flag
Warning, which is in effect from noon to 9 PM MDT Tuesday. the
Fire Weather Watch is no longer in effect.

* IMPACTS: Low Humidities...Hot Temperatures... and Strong Gusty
  Winds...will create erratic fire behavior and new fire starts. 

* AFFECTED AREA: 
  In Central WY...Fire Weather Zones 283 and 288.

* COUNTIES AFFECTED: 
  In Central WY...Fremont.
  In West Central WY...Sublette.

* WIND: Southwest 10 to 20 mph with gusts up to 35 mph.

* HUMIDITY: 11 to 20 percent.

* TEMPERATURES: Zone 283: Highs in the 90s. 
                Zone 288: Highs in the mid 70s to low 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.

&&

$$

WYZ282-285-287-170800-
/O.UPG.KRIW.FW.A.0006.210817T1800Z-210818T0300Z/
/O.NEW.KRIW.FW.W.0013.210817T1800Z-210818T0300Z/
South Big Horn Basin/Worland BLM-South Bighorn Mountains-
Owl Creek Mountains-
150 PM MDT Mon Aug 16 2021

...RED FLAG WARNING IN EFFECT FROM NOON TO 9 PM MDT TUESDAY...

The National Weather Service in Riverton has issued a Red Flag
Warning, which is in effect from noon to 9 PM MDT Tuesday. the
Fire Weather Watch is no longer in effect.

* IMPACTS: Low Humidities...Hot Temperatures...and Strong Gusty
  Winds...will create erratic fire behavior and new fire starts. 

* AFFECTED AREA: 
  In Central WY Fire Zone....285.
  In North Central WY Fire Zones...282...287.

* COUNTIES AFFECTED: 
  In Central WY...Fremont...Natrona.
  In North Central WY...Hot Springs...Johnson...Washakie.

* WIND: Southwest 10 to 20 mph with gusts up to 35 mph.

* HUMIDITY: 11 to 15 percent.

* TEMPERATURES: Highs in the middle to upper 90s.
                Zone 285: High around 90.

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.

&&

$$

WYZ280-289-300-170800-
/O.UPG.KRIW.FW.A.0006.210817T1800Z-210818T0300Z/
/O.NEW.KRIW.FW.W.0013.210817T1800Z-210818T0300Z/
Natrona County/Casper BLM-
Granite/Green/Ferris/Rattlesnake Mountains-Casper Mountain-
150 PM MDT Mon Aug 16 2021

...RED FLAG WARNING IN EFFECT FROM NOON TO 9 PM MDT TUESDAY...

The National Weather Service in Riverton has issued a Red Flag
Warning, which is in effect from noon to 9 PM MDT Tuesday. the
Fire Weather Watch is no longer in effect.

* IMPACTS: Low Humidities...Hot Temperatures...and Strong Gusty
  Winds...will create erratic fire behavior and new fire starts. 

* AFFECTED AREA: 
  In Central WY...Fire Weather Zones 280...289 and 300.

* COUNTIES AFFECTED: 
  In Central WY...Fremont...Natrona.
  In Southwest WY...Sweetwater.

* WIND: Southwest 10 to 20 mph with gusts up to 30 mph.

* HUMIDITY: 11 to 14 percent.

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

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.

&&

$$

WYZ281-170800-
/O.NEW.KRIW.FW.W.0013.210817T1800Z-210818T0300Z/
Johnson County/Casper BLM-
150 PM MDT Mon Aug 16 2021

...RED FLAG WARNING IN EFFECT FROM NOON TO 9 PM MDT TUESDAY...

The National Weather Service in Riverton has issued a Red Flag
Warning, which is in effect from noon to 9 PM MDT Tuesday.

* IMPACTS: Low Humidities...Hot Temperatures...and Strong Gusty
  Winds...will create erratic fire behavior and new fire starts. 

* AFFECTED AREA: 
  In North Central WY...Fire Weather Zone 281.

* COUNTIES AFFECTED: 
  In North Central WY...Johnson.

* WIND: Southwest 10 to 15 mph with gusts up to 30 mph.

* HUMIDITY: 12 to 15 percent.

* TEMPERATURES: Highs in the mid 90s.

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.

&&

$$

WYZ140-286-170300-
/O.CON.KRIW.FW.W.0012.210816T2000Z-210817T0300Z/
Yellowstone National Park-Absaroka Mountains/North Shoshone NF-
150 PM MDT Mon Aug 16 2021

...RED FLAG WARNING REMAINS IN EFFECT UNTIL 9 PM MDT THIS
EVENING...

* IMPACTS: Low Humidities...Hot Temperatures...Strong Gusty 
  Winds...and Dry Thunderstorms with gusty and erratic outflow 
  winds will create erratic fire behavior and new fire starts. 

* AFFECTED AREA: 
  In Northwest WY...Fire Weather Zones 140 and 286.

* COUNTIES AFFECTED: 
  In Central WY...Fremont.
  In North Central WY...Hot Springs...Park.
  In Northwest WY...Yellowstone National Park.

* WIND: Southwest 10 to 20 mph with gusts up to 30 mph.

* THUNDERSTORMS: Isolated dry thunderstorms.

* HUMIDITY: 14 to 18 percent.

* TEMPERATURES: Highs in the lower 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

170 
WWUS85 KRIW 170247
RFWRIW

URGENT - FIRE WEATHER MESSAGE
National Weather Service Riverton WY
847 PM MDT Mon Aug 16 2021

WYZ140-286-170400-
/O.EXP.KRIW.FW.W.0012.000000T0000Z-210817T0300Z/
Yellowstone National Park-Absaroka Mountains/North Shoshone NF-
847 PM MDT Mon Aug 16 2021

...RED FLAG WARNING WILL EXPIRE AT 9 PM MDT THIS EVENING...

Gusty winds and shower and thunderstorm activity will continue to 
decrease this evening. Therefore, the warning will be allowed to 
expire. 

$$

WYZ277>279-171300-
/O.CON.KRIW.FW.W.0013.210817T1800Z-210818T0300Z/
Lincoln and Uinta Counties/Lower Elevations-
Upper Green River Basin/Rock Springs BLM-
Sweetwater County/Rock Springs BLM/Flaming Gorge NRA-
847 PM MDT Mon Aug 16 2021

...RED FLAG WARNING REMAINS IN EFFECT FROM NOON TO 9 PM MDT
TUESDAY...

* IMPACTS: Low Humidities...Hot Temperatures...Strong Gusty 
  Winds...and Dry Thunderstorms with gusty and erratic outflow 
  winds will create erratic fire behavior and new fire starts. 

* AFFECTED AREA: 
  In Southwest WY Fire Zones...277...279.
  In West Central WY Fire Zone....278.

* COUNTIES AFFECTED: 
  In Southwest WY...Sweetwater...Uinta.
  In West Central WY...Lincoln...Sublette.

* WIND: Southwest 10 to 20 mph with gusts up to 35 mph.

* HUMIDITY: 12 to 16 percent.

* TEMPERATURES: Highs in the mid 80s to near 90 degrees.

* THUNDERSTORMS: Isolated to scattered virga showers and dry 
  thunderstorms will develop over zones 277, 278 and the western 
  half of 279. Showers will remain possible Tuesday night.

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.

&&

$$

WYZ283-288-171300-
/O.CON.KRIW.FW.W.0013.210817T1800Z-210818T0300Z/
Upper Wind River Basin/Wind River Basin-
East Wind River Mountains/South Shoshone NF-
847 PM MDT Mon Aug 16 2021

...RED FLAG WARNING REMAINS IN EFFECT FROM NOON TO 9 PM MDT
TUESDAY...

* IMPACTS: Low Humidities...Hot Temperatures...and Strong Gusty
  Winds...will create erratic fire behavior and new fire starts. 

* AFFECTED AREA: 
  In Central WY...Fire Weather Zones 283 and 288.

* COUNTIES AFFECTED: 
  In Central WY...Fremont.
  In West Central WY...Sublette.

* WIND: Southwest 10 to 20 mph with gusts up to 35 mph.

* HUMIDITY: 11 to 15 percent.

* TEMPERATURES: Zone 283: Highs in the 90s. 
                Zone 288: Highs in the mid 70s to low 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.

&&

$$

WYZ281-282-285-287-171300-
/O.CON.KRIW.FW.W.0013.210817T1800Z-210818T0300Z/
Johnson County/Casper BLM-South Big Horn Basin/Worland BLM-
South Bighorn Mountains-Owl Creek Mountains-
847 PM MDT Mon Aug 16 2021

...RED FLAG WARNING REMAINS IN EFFECT FROM NOON TO 9 PM MDT
TUESDAY...

* IMPACTS: Low Humidities...Hot Temperatures...and Strong Gusty
  Winds...will create erratic fire behavior and new fire starts. 

* AFFECTED AREA: 
  In Central WY Fire Zone....285.
  In North Central WY Fire Zones...281...282...287.

* COUNTIES AFFECTED: 
  In Central WY...Fremont...Natrona.
  In North Central WY...Hot Springs...Johnson...Washakie.

* WIND: Southwest 10 to 20 mph with gusts up to 35 mph.

* HUMIDITY: 11 to 15 percent.

* TEMPERATURES: Highs in the middle to upper 90s.
                Zone 285: High around 90.

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.

&&

$$

WYZ280-289-300-171300-
/O.CON.KRIW.FW.W.0013.210817T1800Z-210818T0300Z/
Natrona County/Casper BLM-
Granite/Green/Ferris/Rattlesnake Mountains-Casper Mountain-
847 PM MDT Mon Aug 16 2021

...RED FLAG WARNING REMAINS IN EFFECT FROM NOON TO 9 PM MDT
TUESDAY...

* IMPACTS: Low Humidities...Hot Temperatures...and Strong Gusty
  Winds...will create erratic fire behavior and new fire starts. 

* AFFECTED AREA: 
  In Central WY...Fire Weather Zones 280...289 and 300.

* COUNTIES AFFECTED: 
  In Central WY...Fremont...Natrona.
  In Southwest WY...Sweetwater.

* WIND: Southwest 10 to 20 mph with gusts up to 30 mph.

* HUMIDITY: 11 to 14 percent.

* TEMPERATURES: Highs in the low to mid 90.

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

The office that day

Everything else NWS Riverton, WY issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Aug 15, 6:22 PM MDT	Special Weather Statement	RIW	Natrona	23 min
Aug 15, 6:44 PM MDT	Special Weather Statement	RIW	Natrona	31 min
Aug 16, 2:24 AM MDT	Fire Weather Watch	RIW	Fremont, Hot Springs, Johnson, Lincoln, Natrona, Sublette and 3 more	11 hr
Aug 16, 1:50 PM MDT	Red Flag Warning	RIW	Fremont, Hot Springs, Johnson, Lincoln, Natrona, Sublette and 3 more	31 hr

Nearby

Red Flag Warnings in Wyoming, 2021 Every red flag warning in 2021

Sources

The product and its follow-ups from the Iowa Environmental Mesonet's archive of National Weather Service and Storm Prediction Center text; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.