Alert archive / Wyoming / Red Flag Warnings in 2021

Red Flag Warning 13, NWS Riverton, WY

August 16, 20219 counties in Wyoming

NWS Riverton, WY issued this red flag warning at Aug 16, 2021, 1:50 PM MDT for 9 counties in Wyoming. It took effect at Aug 17, 2021, 12:00 PM MDT. It was in force for 9 hr. 1 report came from inside the area while it was in force.

The area

The counties it named, with what was reported inside it.

The facts

Issued
Aug 16, 2021, 1:50 PM MDT (19:50 UTC)
In effect from
Aug 17, 2021, 12:00 PM MDT
Expired
Aug 17, 2021, 9:00 PM MDT
In force
9 hr
Issued by
NWS Riverton, WY

Counties Fremont County, WY, Hot Springs County, WY, Johnson County, WY, Lincoln County, WY, Natrona County, WY, Sublette County, WY, Sweetwater County, WY, Uinta County, WY, Washakie County, WY

The radar

The Riverton/Lander radar (KRIW), 29 km from the middle of the area, began a volume at 19:47 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.

What was reported inside it

TimeReportWhereRemark
Aug 17, 8:15 PM MDTTSTM WND GST 592 N Kemmerer, WYTHUNDERSTORM OUTFLOW WINDS AT KEMM KEMMERER AIRPORT.

Local storm reports filed while the alert was in force, from inside its polygon or its counties.

The nearest sounding before it

Riverton, WY (KRIW), launched 12:00Z, 7.8 hours before the alert went out and 34 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-pSkew-T log-p diagram, Riverton, WY at 12:00Z on 2021-08-16Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 0 joules per kilogram.LCL10008507005003002001001 km2 km3 km6 km9 km12 km-30°-20°-10°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Riverton, WY at 12:00Z on 2021-08-16The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity -5 square meters per square second.1939Sfc1 km3 km6 km9 kmRMLM
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
0 J/kg
Mixed-layer CIN
No buoyant parcel
Mixed-layer LCL
2896 m above ground
0-6 km bulk shear
22 kt
0-1 km storm-relative helicity
-5 m²/s²
0-3 km storm-relative helicity
3 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

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
4 follow-up statements
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
801 
WWUS85 KRIW 170922
RFWRIW

URGENT - FIRE WEATHER MESSAGE
National Weather Service Riverton WY
322 AM MDT Tue Aug 17 2021

WYZ277>279-180300-
/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-
322 AM MDT Tue Aug 17 2021

...RED FLAG WARNING REMAINS IN EFFECT FROM NOON TODAY TO 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 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 30 mph.

* HUMIDITY: As low as 14 percent.

* TEMPERATURES: Highs in the mid 80s.

* 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 tonight 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.

&&

$$

WYZ283-288-180300-
/O.CON.KRIW.FW.W.0013.210817T1800Z-210818T0300Z/
Upper Wind River Basin/Wind River Basin-
East Wind River Mountains/South Shoshone NF-
322 AM MDT Tue Aug 17 2021

...RED FLAG WARNING REMAINS IN EFFECT FROM NOON TODAY TO 9 PM MDT
THIS EVENING...

* 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 30 mph.

* HUMIDITY: As low as 12 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.

&&

$$

WYZ281-282-285-287-180300-
/O.CON.KRIW.FW.W.0013.210817T1800Z-210818T0300Z/
Johnson County/Casper BLM-South Big Horn Basin/Worland BLM-
South Bighorn Mountains-Owl Creek Mountains-
322 AM MDT Tue Aug 17 2021

...RED FLAG WARNING REMAINS IN EFFECT FROM NOON TODAY TO 9 PM MDT
THIS EVENING...

* 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 15 mph with gusts up to 30 mph.

* HUMIDITY: As low as 12 percent.

* TEMPERATURES: Highs in the lower 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.

&&

$$

WYZ280-289-300-180300-
/O.CON.KRIW.FW.W.0013.210817T1800Z-210818T0300Z/
Natrona County/Casper BLM-
Granite/Green/Ferris/Rattlesnake Mountains-Casper Mountain-
322 AM MDT Tue Aug 17 2021

...RED FLAG WARNING REMAINS IN EFFECT FROM NOON TODAY TO 9 PM MDT
THIS EVENING...

* 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: As low as 12 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
931 
WWUS85 KRIW 171747
RFWRIW

URGENT - FIRE WEATHER MESSAGE
National Weather Service Riverton WY
1147 AM MDT Tue Aug 17 2021

WYZ277>279-180300-
/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-
1147 AM MDT Tue Aug 17 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 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 17 percent.

* TEMPERATURES: Highs in the mid 80s.

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

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.

&&

$$

WYZ283-288-180300-
/O.CON.KRIW.FW.W.0013.210817T1800Z-210818T0300Z/
Upper Wind River Basin/Wind River Basin-
East Wind River Mountains/South Shoshone NF-
1147 AM MDT Tue Aug 17 2021

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

* 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 15 to 20 mph with gusts up to 35 mph.

* HUMIDITY: 11 to 18 percent.

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

&&

$$

WYZ281-282-285-287-180300-
/O.CON.KRIW.FW.W.0013.210817T1800Z-210818T0300Z/
Johnson County/Casper BLM-South Big Horn Basin/Worland BLM-
South Bighorn Mountains-Owl Creek Mountains-
1147 AM MDT Tue Aug 17 2021

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

* 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 15 to 20 mph with gusts up to 30 mph.

* HUMIDITY: 12 to 14 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.

&&

$$

WYZ280-289-300-180300-
/O.CON.KRIW.FW.W.0013.210817T1800Z-210818T0300Z/
Natrona County/Casper BLM-
Granite/Green/Ferris/Rattlesnake Mountains-Casper Mountain-
1147 AM MDT Tue Aug 17 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 Central WY...Fire Weather Zones 280...289 and 300.

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

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

* HUMIDITY: 10 to 15 percent.

* TEMPERATURES: Highs in the low to mid 90s.
                Zone 300: Highs in the mid 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
392 
WWUS85 KRIW 180256
RFWRIW

URGENT - FIRE WEATHER MESSAGE
National Weather Service Riverton WY
856 PM MDT Tue Aug 17 2021

WYZ277>279-180400-
/O.EXP.KRIW.FW.W.0013.000000T0000Z-210818T0300Z/
Lincoln and Uinta Counties/Lower Elevations-
Upper Green River Basin/Rock Springs BLM-
Sweetwater County/Rock Springs BLM/Flaming Gorge NRA-
856 PM MDT Tue Aug 17 2021

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

Sustained wind speeds have decreased and humidity has slowly risen
above critical thresholds Tuesday evening. Therefore, the Red Flag
Warning will be allowed to expire. Gusty outflow wind of 35 to 50 
mph will be possible from any showers or thunderstorms until 10 PM.

$$

WYZ283-288-180400-
/O.EXP.KRIW.FW.W.0013.000000T0000Z-210818T0300Z/
Upper Wind River Basin/Wind River Basin-
East Wind River Mountains/South Shoshone NF-
856 PM MDT Tue Aug 17 2021

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

Sustained wind speeds have decreased and humidity has slowly risen
above critical thresholds Tuesday evening. Therefore, the Red Flag
Warning will be allowed to expire.

$$

WYZ281-282-285-287-180400-
/O.EXP.KRIW.FW.W.0013.000000T0000Z-210818T0300Z/
Johnson County/Casper BLM-South Big Horn Basin/Worland BLM-
South Bighorn Mountains-Owl Creek Mountains-
856 PM MDT Tue Aug 17 2021

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

Sustained wind speeds have decreased and humidity has slowly risen
above critical thresholds Tuesday evening. Therefore, the Red Flag
Warning will be allowed to expire.

$$

WYZ280-289-300-180400-
/O.EXP.KRIW.FW.W.0013.000000T0000Z-210818T0300Z/
Natrona County/Casper BLM-
Granite/Green/Ferris/Rattlesnake Mountains-Casper Mountain-
856 PM MDT Tue Aug 17 2021

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

Sustained wind speeds have decreased and humidity has slowly risen
above critical thresholds Tuesday evening. Therefore, the Red Flag
Warning will be allowed to expire.

$$

http://weather.gov/riverton

The office that day

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

IssuedProductOfficeCountiesLasted
Aug 15, 6:22 PM MDTSpecial Weather StatementRIWNatrona23 min
Aug 15, 6:44 PM MDTSpecial Weather StatementRIWNatrona31 min
Aug 16, 2:24 AM MDTFire Weather WatchRIWFremont, Hot Springs, Johnson, Lincoln, Natrona, Sublette and 3 more11 hr
Aug 16, 2:24 AM MDTRed Flag WarningRIWFremont, Hot Springs, Park, Teton19 hr

Nearby

Red Flag Warnings in Wyoming, 2021Every 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; local storm reports from the same archive; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.