Alert archive / Wyoming / Red Flag Warnings in 2021

Red Flag Warning 26, NWS Riverton, WY

October 3, 20217 counties in Wyoming

NWS Riverton, WY issued this red flag warning at Oct 3, 2021, 1:23 PM MDT for 7 counties in Wyoming. It took effect at Oct 4, 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
Oct 3, 2021, 1:23 PM MDT (19:23 UTC)
In effect from
Oct 4, 2021, 12:00 PM MDT
Expired
Oct 4, 2021, 7:00 PM MDT
In force
7 hr
Issued by
NWS Riverton, WY

Counties 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), 49 km from the middle of the area, began a volume at 19:23 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, 7.4 hours before the alert went out and 45 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 2021-10-03Temperature 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 2021-10-03The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity -20 square meters per square second.193958Sfc1 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
3355 m above ground
0-6 km bulk shear
28 kt
0-1 km storm-relative helicity
-20 m²/s²
0-3 km storm-relative helicity
-18 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

467 
WWUS85 KRIW 031923
RFWRIW

URGENT - FIRE WEATHER MESSAGE
National Weather Service Riverton WY
123 PM MDT Sun Oct 3 2021

WYZ280-281-285-041200-
/O.UPG.KRIW.FW.A.0016.211004T1800Z-211005T0100Z/
/O.NEW.KRIW.FW.W.0026.211004T1800Z-211005T0100Z/
Natrona County/Casper BLM-Johnson County/Casper BLM-
South Bighorn Mountains-
123 PM MDT Sun Oct 3 2021

...RED FLAG WARNING IN EFFECT FROM NOON TO 7 PM MDT MONDAY...

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Weather Watch is no longer in effect.

* 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 Zones...280...285.
  In North Central WY Fire Zone....281.

* 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 25 mph.

* HUMIDITY: 10 to 15 percent.

* TEMPERATURES: Zone 285: Highs in the mid 70s. 
                Zone 280/281: 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.

&&

$$

http://weather.gov/riverton
3 follow-up statements
842 
WWUS85 KRIW 040849
RFWRIW

URGENT - FIRE WEATHER MESSAGE
National Weather Service Riverton WY
249 AM MDT Mon Oct 4 2021

WYZ289-050100-
/O.EXA.KRIW.FW.W.0026.211004T1800Z-211005T0100Z/
Granite/Green/Ferris/Rattlesnake Mountains-
249 AM MDT Mon Oct 4 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.

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

* AFFECTED AREA: 
  In Central WY...Fire Weather Zone 289.

* 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 15 percent.

* TEMPERATURES: Highs around 70.

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.

&&

$$

WYZ286-050100-
/O.EXA.KRIW.FW.W.0026.211004T1800Z-211005T0100Z/
Absaroka Mountains/North Shoshone NF-
249 AM MDT Mon Oct 4 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.

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

* AFFECTED AREA: 
  In Northwest WY...Fire Weather Zone 286.

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

* WIND: Southwest 10 to 15 mph with gusts up to 25 mph.

* HUMIDITY: As low as 13 percent.

* TEMPERATURES: Highs in the lower 60s.

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.

&&

$$

WYZ280-281-285-050100-
/O.CON.KRIW.FW.W.0026.211004T1800Z-211005T0100Z/
Natrona County/Casper BLM-Johnson County/Casper BLM-
South Bighorn Mountains-
249 AM MDT Mon Oct 4 2021

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

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

* AFFECTED AREA: 
  In Central WY Fire Zones...280...285.
  In North Central WY Fire Zone....281.

* 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 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
434 
WWUS85 KRIW 041702
RFWRIW

URGENT - FIRE WEATHER MESSAGE
National Weather Service Riverton WY
1102 AM MDT Mon Oct 4 2021

WYZ280-281-285-289-050100-
/O.CON.KRIW.FW.W.0026.211004T1800Z-211005T0100Z/
Natrona County/Casper BLM-Johnson County/Casper BLM-
South Bighorn Mountains-Granite/Green/Ferris/Rattlesnake Mountains-
1102 AM MDT Mon Oct 4 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 Zones...280...285...289.
  In North Central WY Fire Zone....281.

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

* WIND: Southwest 10 to 15 mph with gusts up to 25 mph.

* HUMIDITY: 10 to 15 percent.

* TEMPERATURES: Zone 285: Highs in the mid 70s. 
                Zone 280/281/289: 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.

&&

$$

WYZ286-050100-
/O.CON.KRIW.FW.W.0026.211004T1800Z-211005T0100Z/
Absaroka Mountains/North Shoshone NF-
1102 AM MDT Mon Oct 4 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 Northwest WY...Fire Weather Zone 286.

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

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

* HUMIDITY: 10 to 18 percent.

* TEMPERATURES: Highs in the mid 60s to lower 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
951 
WWUS85 KRIW 050053
RFWRIW

URGENT - FIRE WEATHER MESSAGE
National Weather Service Riverton WY
653 PM MDT Mon Oct 4 2021

WYZ280-281-285-289-050200-
/O.EXP.KRIW.FW.W.0026.000000T0000Z-211005T0100Z/
Natrona County/Casper BLM-Johnson County/Casper BLM-
South Bighorn Mountains-Granite/Green/Ferris/Rattlesnake Mountains-
653 PM MDT Mon Oct 4 2021

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

Wind speeds are on the decrease this evening and have dropped below
warning thresholds. Therefore, the Red Flag Warning will be allowed
to expire at 7 PM.

$$

WYZ286-050200-
/O.EXP.KRIW.FW.W.0026.000000T0000Z-211005T0100Z/
Absaroka Mountains/North Shoshone NF-
653 PM MDT Mon Oct 4 2021

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

Wind speeds are on the decrease this evening and have generally
fallen below warning thresholds. Therefore, the Red Flag Warning 
will be allowed to expire at 7 PM.

$$

http://weather.gov/riverton

The office that day

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

IssuedProductOfficeCountiesLasted
Oct 3, 2:17 AM MDTFire Weather WatchRIWFremont, Hot Springs, Johnson, Natrona, Washakie11 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.