Alert archive / Wyoming / Red Flag Warnings in 2021

Red Flag Warning 17, NWS Riverton, WY

August 30, 20216 counties in Wyoming

NWS Riverton, WY issued this red flag warning at Aug 30, 2021, 2:37 AM MDT for 6 counties in Wyoming. It took effect at Aug 30, 2021, 2:00 PM MDT. It was in force for 5 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
Aug 30, 2021, 2:37 AM MDT (08:37 UTC)
In effect from
Aug 30, 2021, 2:00 PM MDT
Expired
Aug 30, 2021, 7:00 PM MDT
In force
5 hr
Issued by
NWS Riverton, WY

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

The radar

The Riverton/Lander radar (KRIW), 103 km from the middle of the area, began a volume at 08:34 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, 8.6 hours before the alert went out and 107 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 2021-08-30Temperature 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 2021-08-30The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 65 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
3297 m above ground
0-6 km bulk shear
35 kt
0-1 km storm-relative helicity
65 m²/s²
0-3 km storm-relative helicity
104 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

653 
WWUS85 KRIW 300837
RFWRIW

URGENT - FIRE WEATHER MESSAGE
National Weather Service Riverton WY
237 AM MDT Mon Aug 30 2021

WYZ277>279-289-310100-
/O.NEW.KRIW.FW.W.0017.210830T2000Z-210831T0100Z/
Lincoln and Uinta Counties/Lower Elevations-
Upper Green River Basin/Rock Springs BLM-
Sweetwater County/Rock Springs BLM/Flaming Gorge NRA-
Granite/Green/Ferris/Rattlesnake Mountains-
237 AM MDT Mon Aug 30 2021

...RED FLAG WARNING IN EFFECT FROM 2 PM THIS AFTERNOON TO 7 PM MDT
THIS EVENING...

The National Weather Service in Riverton has issued a Red Flag
Warning, which is in effect from 2 PM this afternoon to 7 PM MDT
this evening.

* IMPACTS: Low Humidities and Strong Gusty Winds may lead to
  erratic fire behavior and quick growth of any new fire starts. 

* AFFECTED AREA: 
  In Central WY Fire Zone....289.
  In Southwest WY Fire Zones...277...279.
  In West Central WY Fire Zone....278.

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

* WIND: West 15 to 20 mph with gusts 30 to 35 mph.

* HUMIDITY: 10 to 15 percent.

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
427 
WWUS85 KRIW 310042
RFWRIW

URGENT - FIRE WEATHER MESSAGE
National Weather Service Riverton WY
642 PM MDT Mon Aug 30 2021

WYZ277>279-289-310145-
/O.EXP.KRIW.FW.W.0017.000000T0000Z-210831T0100Z/
Lincoln and Uinta Counties/Lower Elevations-
Upper Green River Basin/Rock Springs BLM-
Sweetwater County/Rock Springs BLM/Flaming Gorge NRA-
Granite/Green/Ferris/Rattlesnake Mountains-
642 PM MDT Mon Aug 30 2021

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

Winds have decreased across the area this evening. Accordingly, the
Red Flag Warning will be allowed to expire.

$$

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.