Alert archive / Wyoming / Red Flag Warnings in 2021

Red Flag Warning 24, NWS Riverton, WY

September 25, 20215 counties in Wyoming

NWS Riverton, WY issued this red flag warning at Sep 25, 2021, 1:42 AM MDT for 5 counties in Wyoming. It took effect at Sep 25, 2021, 12:00 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: Sep 25, 2021, 1:42 AM MDT (07:42 UTC)
In effect from: Sep 25, 2021, 12:00 PM MDT
Expired: Sep 25, 2021, 7:00 PM MDT
In force: 7 hr
Issued by: NWS Riverton, WY

Counties Fremont County, WY, Lincoln County, WY, Natrona County, WY, Sweetwater County, WY, Uinta County, WY

The radar

The Riverton/Lander radar (KRIW), 105 km from the middle of the area, began a volume at 07:41 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, 7.7 hours before the alert went out and 108 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: 0 J/kg
Mixed-layer CIN: No buoyant parcel
Mixed-layer LCL: 2916 m above ground
0-6 km bulk shear: 29 kt
0-1 km storm-relative helicity: 79 m²/s²
0-3 km storm-relative helicity: 159 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

The text

As transmitted.

365 
WWUS85 KRIW 250742
RFWRIW

URGENT - FIRE WEATHER MESSAGE
National Weather Service Riverton WY
142 AM MDT Sat Sep 25 2021

WYZ277-279-260100-
/O.UPG.KRIW.FW.A.0014.210925T1800Z-210926T0100Z/
/O.NEW.KRIW.FW.W.0024.210925T1800Z-210926T0100Z/
Lincoln and Uinta Counties/Lower Elevations-
Sweetwater County/Rock Springs BLM/Flaming Gorge NRA-
142 AM MDT Sat Sep 25 2021

...RED FLAG WARNING IN EFFECT FROM NOON TODAY TO 7 PM MDT THIS
EVENING...

The National Weather Service in Riverton has issued a Red Flag
Warning, which is in effect from noon today to 7 PM MDT this
evening. The Fire Weather Watch is no longer in effect.

* IMPACTS: Low Humidities...Unseasonably Warm Temperatures...and
  Gusty Winds will create erratic fire behavior with any new fire 
  starts. 

* AFFECTED AREA: 
  In Southwest WY...Fire Weather Zones 277 and 279.

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

* WIND: West 15 to 20 mph with gusts 25 to 30 mph.

* HUMIDITY: As low as 12 percent.

* TEMPERATURES: Highs in the mid to upper 70s.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

$$

WYZ280-289-260100-
/O.UPG.KRIW.FW.A.0014.210925T1800Z-210926T0100Z/
/O.NEW.KRIW.FW.W.0024.210925T1800Z-210926T0100Z/
Natrona County/Casper BLM-
Granite/Green/Ferris/Rattlesnake Mountains-
142 AM MDT Sat Sep 25 2021

...RED FLAG WARNING IN EFFECT FROM NOON TODAY TO 7 PM MDT THIS
EVENING...

The National Weather Service in Riverton has issued a Red Flag
Warning, which is in effect from noon today to 7 PM MDT this
evening. The Fire Weather Watch is no longer in effect.

* IMPACTS: Low Humidities...Unseasonably Warm Temperatures...and
  Gusty Winds will create erratic fire behavior with any new fire 
  starts. 

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

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

* WIND: West 15 to 25 mph with gusts 30 to 35 mph.

* HUMIDITY: As low as 12 percent.

* TEMPERATURES: Highs in the upper 70s to 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 gusty  
winds...low relative humidity...and warm temperatures can 
contribute to extreme fire behavior.

&&

$$

http://weather.gov/riverton

2 follow-up statements

606 
WWUS85 KRIW 251743
RFWRIW

URGENT - FIRE WEATHER MESSAGE
National Weather Service Riverton WY
1143 AM MDT Sat Sep 25 2021

WYZ277-279-260100-
/O.CON.KRIW.FW.W.0024.210925T1800Z-210926T0100Z/
Lincoln and Uinta Counties/Lower Elevations-
Sweetwater County/Rock Springs BLM/Flaming Gorge NRA-
1143 AM MDT Sat Sep 25 2021

...RED FLAG WARNING REMAINS IN EFFECT UNTIL 7 PM MDT THIS
EVENING...

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

* AFFECTED AREA: 
  In Southwest WY...Fire Weather Zones 277 and 279.

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

* WIND: West 15 to 20 mph with gusts up to 30 mph.

* HUMIDITY: As low as 12 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 gusty
winds...low relative humidity...and warm temperatures can
contribute to extreme fire behavior.

&&

$$

WYZ280-289-260100-
/O.CON.KRIW.FW.W.0024.210925T1800Z-210926T0100Z/
Natrona County/Casper BLM-
Granite/Green/Ferris/Rattlesnake Mountains-
1143 AM MDT Sat Sep 25 2021

...RED FLAG WARNING REMAINS IN EFFECT UNTIL 7 PM MDT THIS
EVENING...

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

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

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

* WIND: West 15 to 20 mph with gusts up to 35 mph.

* HUMIDITY: As low as 12 percent.

* TEMPERATURES: Highs in the upper 70s to 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 gusty
winds...low relative humidity...and warm temperatures can
contribute to extreme fire behavior.

&&

$$

http://weather.gov/riverton

914 
WWUS85 KRIW 260033
RFWRIW

URGENT - FIRE WEATHER MESSAGE
National Weather Service Riverton WY
633 PM MDT Sat Sep 25 2021

WYZ277-279-260145-
/O.EXP.KRIW.FW.W.0024.000000T0000Z-210926T0100Z/
Lincoln and Uinta Counties/Lower Elevations-
Sweetwater County/Rock Springs BLM/Flaming Gorge NRA-
633 PM MDT Sat Sep 25 2021

...RED FLAG WARNING WILL EXPIRE AT 7 PM MDT THIS EVENING...

The red flag warning will expire at 7 PM.

$$

WYZ280-289-260145-
/O.EXP.KRIW.FW.W.0024.000000T0000Z-210926T0100Z/
Natrona County/Casper BLM-
Granite/Green/Ferris/Rattlesnake Mountains-
633 PM MDT Sat Sep 25 2021

...RED FLAG WARNING WILL EXPIRE AT 7 PM MDT THIS EVENING...

The red flag warning will expire at 7 PM.

$$

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.