Alert archive / Wyoming / Red Flag Warnings in 2021
Red Flag Warning 8, NWS Riverton, WY
NWS Riverton, WY issued this red flag warning at Jul 19, 2021, 1:28 PM MDT for 8 counties in Wyoming. It took effect at Jul 20, 2021, 12:00 PM MDT. It was in force for 9 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
- Jul 19, 2021, 1:28 PM MDT (19:28 UTC)
- In effect from
- Jul 20, 2021, 12:00 PM MDT
- Expired
- Jul 20, 2021, 9:00 PM MDT
- In force
- 9 hr
- Issued by
- NWS Riverton, WY
Counties Big Horn County, WY, Fremont County, WY, Hot Springs County, WY, Johnson County, WY, Natrona County, WY, Park County, WY, Sweetwater County, WY, Washakie County, WY
The radar
The Riverton/Lander radar (KRIW), 63 km from the middle of the area, began a volume at 19:28 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 12:00Z, 7.5 hours before the alert went out and 59 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.
- Mixed-layer CAPE
- 0 J/kg
- Mixed-layer CIN
- No buoyant parcel
- Mixed-layer LCL
- 3242 m above ground
- 0-6 km bulk shear
- 14 kt
- 0-1 km storm-relative helicity
- -35 m²/s²
- 0-3 km storm-relative helicity
- -27 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.0
The text
As transmitted.
146
WWUS85 KRIW 191928
RFWRIW
URGENT - FIRE WEATHER MESSAGE
National Weather Service Riverton WY
128 PM MDT Mon Jul 19 2021
WYZ275-276-279-281>283-285-287-201300-
/O.NEW.KRIW.FW.W.0008.210720T1800Z-210721T0300Z/
North Big Horn Basin/Worland BLM-Cody Foothills-
Sweetwater County/Rock Springs BLM/Flaming Gorge NRA-
Johnson County/Casper BLM-South Big Horn Basin/Worland BLM-
Upper Wind River Basin/Wind River Basin-South Bighorn Mountains-
Owl Creek Mountains-
128 PM MDT Mon Jul 19 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: Increasing thunderstorm activity and hot temperatures
will create erratic fire behavior and new fire starts.
* AFFECTED AREA:
In Central WY Fire Zones...283...285.
In North Central WY Fire Zones...275...276...281...282...287.
In Southwest WY Fire Zone....279.
* COUNTIES AFFECTED:
In Central WY...Fremont...Natrona.
In North Central WY...Big Horn...Hot Springs...Johnson...Park
Washakie.
In Southwest WY...Sweetwater.
* THUNDERSTORMS: Any lightning activity could lead to new fire
starts. Fuels are very dry and little rain has fallen over the
past few weeks at many locations.
* TEMPERATURES: Highs Tuesday in the 90s, except for in the 80s
across Zone 279.
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.
&&
$$
WYZ140-277-278-286-288-414>416-201300-
/O.EXT.KRIW.FW.W.0007.000000T0000Z-210721T0300Z/
Yellowstone National Park-
Lincoln and Uinta Counties/Lower Elevations-
Upper Green River Basin/Rock Springs BLM-
Absaroka Mountains/North Shoshone NF-
East Wind River Mountains/South Shoshone NF-
Salt and Wyoming Ranges/West Zone Bridger Teton NF-
North Zone Bridger Teton NF and Grand Teton NP-
West Wind River Mountains/East Zone Bridger Teton NF-
128 PM MDT Mon Jul 19 2021
...RED FLAG WARNING NOW IN EFFECT UNTIL 9 PM MDT TUESDAY...
* IMPACTS: Increasing thunderstorm activity and above normal
temperatures will create erratic fire behavior and new fire
starts.
* AFFECTED AREA:
In Central WY Fire Zone....288.
In Northwest WY Fire Zones...140...286...415.
In Southwest WY Fire Zone....277.
In West Central WY Fire Zones...278...414...416.
* COUNTIES AFFECTED:
In Central WY...Fremont.
In North Central WY...Hot Springs...Park.
In Northwest WY...Yellowstone National Park.
In Southwest WY...Sweetwater...Teton...Uinta.
In West Central WY...Lincoln...Sublette.
* THUNDERSTORMS: Thunderstorms are expected through around sunset
Monday before diminishing. The best chance for storms Monday will
be from 4 PM to 8 PM MDT. The thunderstorms will be more
widespread Tuesday afternoon and evening. Any lightning activity
could lead to new fire starts. Fuels are very dry and little rain
has fallen over the past few weeks at many locations.
* TEMPERATURES: Highs Monday 85 to around 90, with 70s to lower
80s in the mountains. Slightly cooler Tuesday with highs in the
80s, with 65 to 80 in the mountains.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
A Red Flag Warning means that critical fire weather conditions are
either occurring now....or will shortly. A combination of strong
winds...low relative humidity...and warm temperatures can
contribute to extreme fire behavior.
&&
$$
http://weather.gov/riverton3 follow-up statements
553
WWUS85 KRIW 200909
RFWRIW
URGENT - FIRE WEATHER MESSAGE
National Weather Service Riverton WY
309 AM MDT Tue Jul 20 2021
WYZ140-277-278-286-288-414>416-210300-
/O.CON.KRIW.FW.W.0007.000000T0000Z-210721T0300Z/
Yellowstone National Park-
Lincoln and Uinta Counties/Lower Elevations-
Upper Green River Basin/Rock Springs BLM-
Absaroka Mountains/North Shoshone NF-
East Wind River Mountains/South Shoshone NF-
Salt and Wyoming Ranges/West Zone Bridger Teton NF-
North Zone Bridger Teton NF and Grand Teton NP-
West Wind River Mountains/East Zone Bridger Teton NF-
309 AM MDT Tue Jul 20 2021
...RED FLAG WARNING REMAINS IN EFFECT UNTIL 9 PM MDT THIS
EVENING...
* IMPACTS: Hot Temperatures and Increasing Thunderstorm Activity
will create erratic fire behavior and new fire starts.
* AFFECTED AREA:
In Central WY Fire Zone....288.
In Northwest WY Fire Zones...140...286...415.
In Southwest WY Fire Zone....277.
In West Central WY Fire Zones...278...414...416.
* COUNTIES AFFECTED:
In Central WY...Fremont.
In North Central WY...Hot Springs...Park.
In Northwest WY...Yellowstone National Park.
In Southwest WY...Sweetwater...Teton...Uinta.
In West Central WY...Lincoln...Sublette.
* THUNDERSTORMS: Isolated thunderstorms will occur through late
morning. Then thunderstorm coverage will increase after 12 PM and
continue through 8 PM MDT. Storms will decrease after 8 PM across
the area. Any lightning activity could lead to new fire starts.
Fuels are very dry and little rain has fallen over the past few
weeks at many locations.
* TEMPERATURES: Highs in the 80s at the lower elevations. Highs in
the 70s in the mountains.
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.
&&
$$
WYZ275-276-279-281>283-285-287-210300-
/O.CON.KRIW.FW.W.0008.210720T1800Z-210721T0300Z/
North Big Horn Basin/Worland BLM-Cody Foothills-
Sweetwater County/Rock Springs BLM/Flaming Gorge NRA-
Johnson County/Casper BLM-South Big Horn Basin/Worland BLM-
Upper Wind River Basin/Wind River Basin-South Bighorn Mountains-
Owl Creek Mountains-
309 AM MDT Tue Jul 20 2021
...RED FLAG WARNING REMAINS IN EFFECT FROM NOON TODAY TO 9 PM MDT
THIS EVENING...
* IMPACTS: Hot Temperatures and Increasing Thunderstorm Activity
will create erratic fire behavior and new fire starts.
* AFFECTED AREA:
In Central WY Fire Zones...283...285.
In North Central WY Fire Zones...275...276...281...282...287.
In Southwest WY Fire Zone....279.
* COUNTIES AFFECTED:
In Central WY...Fremont...Natrona.
In North Central WY...Big Horn...Hot Springs...Johnson...Park
Washakie.
In Southwest WY...Sweetwater.
* THUNDERSTORMS: Isolated to widely scattered thunderstorms are
expected this afternoon through sunset this evening. Any
lightning activity could lead to new fire starts. Fuels are very
dry and little rain has fallen over the past few weeks at many
locations.
* TEMPERATURES: Highs in the upper 80s to mid 90s. Highs in the 70s
for the mountain zones.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
A Red Flag Warning means that critical fire weather conditions are
either occurring now....or will shortly. A combination of strong
winds...low relative humidity...and warm temperatures can
contribute to extreme fire behavior.
&&
$$
http://weather.gov/riverton952
WWUS85 KRIW 201959
RFWRIW
URGENT - FIRE WEATHER MESSAGE
National Weather Service Riverton WY
159 PM MDT Tue Jul 20 2021
WYZ140-277-278-286-288-414>416-210300-
/O.CON.KRIW.FW.W.0007.000000T0000Z-210721T0300Z/
Yellowstone National Park-
Lincoln and Uinta Counties/Lower Elevations-
Upper Green River Basin/Rock Springs BLM-
Absaroka Mountains/North Shoshone NF-
East Wind River Mountains/South Shoshone NF-
Salt and Wyoming Ranges/West Zone Bridger Teton NF-
North Zone Bridger Teton NF and Grand Teton NP-
West Wind River Mountains/East Zone Bridger Teton NF-
159 PM MDT Tue Jul 20 2021
...RED FLAG WARNING REMAINS IN EFFECT UNTIL 9 PM MDT THIS
EVENING...
* IMPACTS: Increasing thunderstorm activity and above normal
temperatures will create erratic fire behavior and new fire
starts.
* AFFECTED AREA:
In Central WY Fire Zone....288.
In Northwest WY Fire Zones...140...286...415.
In Southwest WY Fire Zone....277.
In West Central WY Fire Zones...278...414...416.
* COUNTIES AFFECTED:
In Central WY...Fremont.
In North Central WY...Hot Springs...Park.
In Northwest WY...Yellowstone National Park.
In Southwest WY...Sweetwater...Teton...Uinta.
In West Central WY...Lincoln...Sublette.
* THUNDERSTORMS: Thunderstorms will become more common through the
afternoon and continue until around sunset. Any lightning
activity could lead to new fire starts. Fuels are very dry and
little rain has fallen over the past few weeks at many locations.
* TEMPERATURES: Highs 80 to 85, with upper 60s and 70s mountains.
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.
&&
$$
WYZ275-276-279-281>283-285-287-210300-
/O.CON.KRIW.FW.W.0008.000000T0000Z-210721T0300Z/
North Big Horn Basin/Worland BLM-Cody Foothills-
Sweetwater County/Rock Springs BLM/Flaming Gorge NRA-
Johnson County/Casper BLM-South Big Horn Basin/Worland BLM-
Upper Wind River Basin/Wind River Basin-South Bighorn Mountains-
Owl Creek Mountains-
159 PM MDT Tue Jul 20 2021
...RED FLAG WARNING REMAINS IN EFFECT UNTIL 9 PM MDT THIS
EVENING...
* IMPACTS: Increasing thunderstorm activity and above normal
temperatures will create erratic fire behavior and new fire
starts.
* AFFECTED AREA:
In Central WY Fire Zones...283...285.
In North Central WY Fire Zones...275...276...281...282...287.
In Southwest WY Fire Zone....279.
* COUNTIES AFFECTED:
In Central WY...Fremont...Natrona.
In North Central WY...Big Horn...Hot Springs...Johnson...Park
Washakie.
In Southwest WY...Sweetwater.
* THUNDERSTORMS: Thunderstorms will become more common through the
afternoon and continue until around sunset. Any lightning
activity could lead to new fire starts. Fuels are very dry and
little rain has fallen over the past few weeks at many locations.
* TEMPERATURES: Highs in the upper 80s to mid 90s, with mainly 70s
in the mountains.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
A Red Flag Warning means that critical fire weather conditions are
either occurring now....or will shortly. A combination of strong
winds...low relative humidity...and warm temperatures can
contribute to extreme fire behavior.
&&
$$
http://weather.gov/riverton647 WWUS85 KRIW 210236 RFWRIW URGENT - FIRE WEATHER MESSAGE National Weather Service Riverton WY 836 PM MDT Tue Jul 20 2021 WYZ140-277-278-286-288-414>416-210345- /O.EXP.KRIW.FW.W.0007.000000T0000Z-210721T0300Z/ Yellowstone National Park- Lincoln and Uinta Counties/Lower Elevations- Upper Green River Basin/Rock Springs BLM- Absaroka Mountains/North Shoshone NF- East Wind River Mountains/South Shoshone NF- Salt and Wyoming Ranges/West Zone Bridger Teton NF- North Zone Bridger Teton NF and Grand Teton NP- West Wind River Mountains/East Zone Bridger Teton NF- 836 PM MDT Tue Jul 20 2021 ...RED FLAG WARNING WILL EXPIRE AT 9 PM MDT THIS EVENING... Thunderstorm activity is decreasing this evening, with temperatures cooling and relative humidities rising; therefore, the Red Flag Warning will be allowed to expire. $$ WYZ275-276-279-281>283-285-287-210345- /O.EXP.KRIW.FW.W.0008.000000T0000Z-210721T0300Z/ North Big Horn Basin/Worland BLM-Cody Foothills- Sweetwater County/Rock Springs BLM/Flaming Gorge NRA- Johnson County/Casper BLM-South Big Horn Basin/Worland BLM- Upper Wind River Basin/Wind River Basin-South Bighorn Mountains- Owl Creek Mountains- 836 PM MDT Tue Jul 20 2021 ...RED FLAG WARNING WILL EXPIRE AT 9 PM MDT THIS EVENING... Thunderstorm activity is decreasing this evening, with temperatures cooling and relative humidities rising; therefore, the Red Flag Warning will be allowed to expire. $$ http://weather.gov/riverton
The office that day
Everything else NWS Riverton, WY issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Jul 19, 3:10 AM MDT | Red Flag Warning | RIW | Fremont, Hot Springs, Lincoln, Park, Sublette, Sweetwater and 2 more | 42 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; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.