Alert archive / Wyoming / Red Flag Warnings in 2021

Red Flag Warning 28, NWS Riverton, WY

November 23, 20215 counties in Wyoming

NWS Riverton, WY issued this red flag warning at Nov 23, 2021, 3:00 AM MST for 5 counties in Wyoming. It was in force for 13 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
Nov 23, 2021, 3:00 AM MST (10:00 UTC)
Expired
Nov 23, 2021, 4:00 PM MST
In force
13 hr
Issued by
NWS Riverton, WY

Counties Fremont County, WY, Hot Springs County, WY, Johnson County, WY, Natrona County, WY, Washakie County, WY

The radar

The Riverton/Lander radar (KRIW), 86 km from the middle of the area, began a volume at 09:58 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
Nov 23, 9:35 AM MSTNON-TSTM WND GST 616 Nw Mills, WYASOS STATION KCPR CASPER 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 00:00Z, 10.0 hours before the alert went out and 81 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 2021-11-23Temperature 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 00:00Z on 2021-11-23The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 25 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
3238 m above ground
0-6 km bulk shear
29 kt
0-1 km storm-relative helicity
25 m²/s²
0-3 km storm-relative helicity
124 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

485 
WWUS85 KRIW 231000
RFWRIW

URGENT - FIRE WEATHER MESSAGE
National Weather Service Riverton WY
300 AM MST Tue Nov 23 2021

WYZ280-232300-
/O.UPG.KRIW.FW.A.0018.211123T1700Z-211123T2300Z/
/O.NEW.KRIW.FW.W.0028.211123T1000Z-211123T2300Z/
Natrona County/Casper BLM-
300 AM MST Tue Nov 23 2021

...RED FLAG WARNING IN EFFECT UNTIL 4 PM MST THIS AFTERNOON...

The National Weather Service in Riverton has issued a Red Flag
Warning, which is in effect until 4 PM MST this afternoon. the
Fire Weather Watch is no longer in effect.

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

* AFFECTED AREA: 
  In Central WY...Fire Weather Zone 280.

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

* WIND: Southwest 35 to 45 mph with gusts up to 60 mph.

* HUMIDITY: 10 to 15 percent.

* TEMPERATURES: Lows around 45. Highs in the mid to upper 50s.

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.

&&

$$

WYZ281-232300-
/O.UPG.KRIW.FW.A.0018.211123T1700Z-211123T2300Z/
/O.NEW.KRIW.FW.W.0028.211123T1700Z-211123T2300Z/
Johnson County/Casper BLM-
300 AM MST Tue Nov 23 2021

...RED FLAG WARNING IN EFFECT FROM 10 AM THIS MORNING TO 4 PM MST
THIS AFTERNOON...

The National Weather Service in Riverton has issued a Red Flag
Warning, which is in effect from 10 AM this morning to 4 PM MST
this afternoon. the Fire Weather Watch is no longer in effect.

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

* AFFECTED AREA: 
  In North Central WY...Fire Weather Zone 281.

* COUNTIES AFFECTED: 
  In North Central WY...Johnson.

* WIND: West 15 to 25 mph with gusts up to 40 mph.

* HUMIDITY: 10 to 15 percent.

* TEMPERATURES: Highs in the upper 50s to near 60.

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.

&&

$$

WYZ285-232300-
/O.NEW.KRIW.FW.W.0028.211123T1700Z-211123T2300Z/
South Bighorn Mountains-
300 AM MST Tue Nov 23 2021

...RED FLAG WARNING IN EFFECT FROM 10 AM THIS MORNING TO 4 PM MST
THIS AFTERNOON...

The National Weather Service in Riverton has issued a Red Flag
Warning, which is in effect from 10 AM this morning to 4 PM MST
this afternoon.

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

* AFFECTED AREA: 
  In Central WY...Fire Weather Zone 285.

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

* WIND: West 20 to 30 mph with gusts up to 50 mph.

* HUMIDITY: 12 to 15 percent.

* TEMPERATURES: Highs in the upper 40s to low 50s.

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
1 follow-up statement
143 
WWUS85 KRIW 232240
RFWRIW

URGENT - FIRE WEATHER MESSAGE
National Weather Service Riverton WY
340 PM MST Tue Nov 23 2021

WYZ280-232345-
/O.EXP.KRIW.FW.W.0028.000000T0000Z-211123T2300Z/
Natrona County/Casper BLM-
340 PM MST Tue Nov 23 2021

...RED FLAG WARNING WILL EXPIRE AT 4 PM MST THIS AFTERNOON...

Winds have begun to decrease this evening which will lower the 
fire danger. Cooler air and higher relative humidities arrive 
overnight as a cold front pushes in from the north.

$$

WYZ281-285-232345-
/O.EXP.KRIW.FW.W.0028.000000T0000Z-211123T2300Z/
Johnson County/Casper BLM-South Bighorn Mountains-
340 PM MST Tue Nov 23 2021

...RED FLAG WARNING WILL EXPIRE AT 4 PM MST THIS AFTERNOON...

Winds have begun to decrease this evening which will lower the 
fire danger. Cooler air and higher relative humidities arrive 
overnight as a cold front pushes in from the north.

$$

http://weather.gov/riverton

The office that day

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

IssuedProductOfficeCountiesLasted
Nov 23, 11:50 AM MSTWinter Weather AdvisoryRIWFremont, Lincoln, Sublette, Teton20 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.