Alert archive / Wyoming / Red Flag Warnings in 2021

Red Flag Warning 2, NWS Riverton, WY

June 17, 20217 counties in Wyoming

NWS Riverton, WY issued this red flag warning at Jun 17, 2021, 3:40 AM MDT for 7 counties in Wyoming. It took effect at Jun 17, 2021, 12:00 PM MDT. It was in force for 8 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
Jun 17, 2021, 3:40 AM MDT (09:40 UTC)
In effect from
Jun 17, 2021, 12:00 PM MDT
Expired
Jun 17, 2021, 8:00 PM MDT
In force
8 hr
Issued by
NWS Riverton, WY

Counties Fremont County, WY, Hot Springs County, WY, Lincoln County, WY, Natrona County, WY, Park County, WY, Sublette County, WY, Teton County, WY

The radar

The Riverton/Lander radar (KRIW), 67 km from the middle of the area, began a volume at 09:45 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, 9.7 hours before the alert went out and 73 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 00:00Z on 2021-06-17Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 12 joules per kilogram.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 km-30°-20°-10°0°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Riverton, WY at 00:00Z on 2021-06-17The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 18 square meters per square second.19395878Sfc1 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
12 J/kg
Mixed-layer CIN
-18 J/kg
Mixed-layer LCL
4644 m above ground
0-6 km bulk shear
25 kt
0-1 km storm-relative helicity
18 m²/s²
0-3 km storm-relative helicity
35 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

270 
WWUS85 KRIW 170940
RFWRIW

URGENT - FIRE WEATHER MESSAGE
National Weather Service Riverton WY
340 AM MDT Thu Jun 17 2021

WYZ280-300-172100-
/O.NEW.KRIW.FW.W.0002.210617T1800Z-210618T0200Z/
Natrona County/Casper BLM-Casper Mountain-
340 AM MDT Thu Jun 17 2021

...RED FLAG WARNING IN EFFECT FROM NOON TODAY TO 8 PM MDT THIS
EVENING...

The National Weather Service in Riverton has issued a Red Flag
Warning, which is in effect from noon today to 8 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 and 300.

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

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

* HUMIDITY: As low as 8 percent.

* TEMPERATURES: Highs in the lower 90s across lower elevations and
  upper 80s across Casper Mountain.

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.

&&

$$

WYZ414-416-172100-
/O.NEW.KRIW.FW.W.0002.210617T1800Z-210618T0200Z/
Salt and Wyoming Ranges/West Zone Bridger Teton NF-
West Wind River Mountains/East Zone Bridger Teton NF-
340 AM MDT Thu Jun 17 2021

...RED FLAG WARNING IN EFFECT FROM NOON TODAY TO 8 PM MDT THIS
EVENING...

The National Weather Service in Riverton has issued a Red Flag
Warning, which is in effect from noon today to 8 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 West Central WY...Fire Weather Zones 414 and 416.

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

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

* HUMIDITY: As low as 13 percent.

* TEMPERATURES: Highs generally in the mid 70s.

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
2 follow-up statements
732 
WWUS85 KRIW 171710
RFWRIW

URGENT - FIRE WEATHER MESSAGE
National Weather Service Riverton WY
1110 AM MDT Thu Jun 17 2021

WYZ286-288-180200-
/O.EXA.KRIW.FW.W.0002.210617T1800Z-210618T0200Z/
Absaroka Mountains/North Shoshone NF-
East Wind River Mountains/South Shoshone NF-
1110 AM MDT Thu Jun 17 2021

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

The National Weather Service in Riverton has issued a Red Flag
Warning, which is in effect until 8 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....288.
  In Northwest WY Fire Zone....286.

* COUNTIES AFFECTED: 
  In Central WY...Fremont.
  In North Central WY...Hot Springs...Park.
  In West Central WY...Sublette.

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

* HUMIDITY: As low as 9 percent.

* TEMPERATURES: Highs in the mid 70s.

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.

&&

$$

WYZ280-300-180200-
/O.CON.KRIW.FW.W.0002.210617T1800Z-210618T0200Z/
Natrona County/Casper BLM-Casper Mountain-
1110 AM MDT Thu Jun 17 2021

...RED FLAG WARNING REMAINS IN EFFECT UNTIL 8 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 and 300.

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

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

* HUMIDITY: As low as 8 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.

&&

$$

WYZ414-416-180200-
/O.CON.KRIW.FW.W.0002.210617T1800Z-210618T0200Z/
Salt and Wyoming Ranges/West Zone Bridger Teton NF-
West Wind River Mountains/East Zone Bridger Teton NF-
1110 AM MDT Thu Jun 17 2021

...RED FLAG WARNING REMAINS IN EFFECT UNTIL 8 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 West Central WY...Fire Weather Zones 414 and 416.

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

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

* HUMIDITY: As low as 13 percent.

* TEMPERATURES: Highs in the mid 70s.

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
923 
WWUS85 KRIW 180203
RFWRIW

URGENT - FIRE WEATHER MESSAGE
National Weather Service Riverton WY
803 PM MDT Thu Jun 17 2021

WYZ280-300-180315-
/O.EXP.KRIW.FW.W.0002.000000T0000Z-210618T0200Z/
Natrona County/Casper BLM-Casper Mountain-
803 PM MDT Thu Jun 17 2021

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

The red flag warning for most of Natrona County will be allowed to
expire this evening as wind speeds have decreased and humidities 
are starting to rise. Critical fire weather conditions are not 
expected tomorrow with lighter northeast winds and humidities 
between 15 and 20 percent.

$$

WYZ414-416-180315-
/O.EXP.KRIW.FW.W.0002.000000T0000Z-210618T0200Z/
Salt and Wyoming Ranges/West Zone Bridger Teton NF-
West Wind River Mountains/East Zone Bridger Teton NF-
803 PM MDT Thu Jun 17 2021

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

The red flag warning for portions of the western WY mountains will
be allowed to expire this evening as wind speeds become lighter and
humidities increase. Breezy northwest wind is likely along the
southwest portions of the Wind River Mountains for the next couple
of hours. Elevated fire weather conditions are likely Friday as
humidities get down to around 15 percent with northwest winds
gusting 20 to 25 mph.

$$

WYZ286-288-180315-
/O.EXP.KRIW.FW.W.0002.000000T0000Z-210618T0200Z/
Absaroka Mountains/North Shoshone NF-
East Wind River Mountains/South Shoshone NF-
803 PM MDT Thu Jun 17 2021

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

The red flag warning for the Absaroka Mountains and the east side
of the Wind River Mountains will be allowed to expire this evening
as wind speeds decrease and humidities gradually increase. Breezy
west-northwest winds will continue for the next couple of hours
though at higher elevations and along the southern portions of the
Absaroka Mountains and Wind River Mountains. Elevated fire weather
conditions are possible along the southeast portion of the Wind
River Mountains Friday afternoon.

$$

http://weather.gov/riverton

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.