Alert archive / Wyoming / Red Flag Warnings in 2021
Red Flag Warning 14, NWS Riverton, WY
NWS Riverton, WY issued this red flag warning at Aug 22, 2021, 12:38 PM MDT for 6 counties in Wyoming. It took effect at Aug 23, 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
- Aug 22, 2021, 12:38 PM MDT (18:38 UTC)
- In effect from
- Aug 23, 2021, 12:00 PM MDT
- Expired
- Aug 23, 2021, 8:00 PM MDT
- In force
- 8 hr
- Issued by
- NWS Riverton, WY
Counties Fremont County, WY, Hot Springs County, WY, Johnson County, WY, Natrona County, WY, Sweetwater County, WY, Washakie County, WY
The radar
The Riverton/Lander radar (KRIW), 55 km from the middle of the area, began a volume at 18:40 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, 6.6 hours before the alert went out and 49 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.
- Mixed-layer CAPE
- 0 J/kg
- Mixed-layer CIN
- No buoyant parcel
- Mixed-layer LCL
- 1671 m above ground
- 0-6 km bulk shear
- 63 kt
- 0-1 km storm-relative helicity
- 110 m²/s²
- 0-3 km storm-relative helicity
- 119 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.0
The text
As transmitted.
500 WWUS85 KRIW 221838 RFWRIW URGENT - FIRE WEATHER MESSAGE National Weather Service Riverton WY 1238 PM MDT Sun Aug 22 2021 WYZ280-281-285-289-231200- /O.NEW.KRIW.FW.W.0014.210823T1800Z-210824T0200Z/ Natrona County/Casper BLM-Johnson County/Casper BLM- South Bighorn Mountains-Granite/Green/Ferris/Rattlesnake Mountains- 1238 PM MDT Sun Aug 22 2021 ...RED FLAG WARNING IN EFFECT FROM NOON TO 8 PM MDT MONDAY... The National Weather Service in Riverton has issued a Red Flag Warning, which is in effect from noon to 8 PM MDT Monday. * 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 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 15 to 25 mph with gusts up to 40 mph. * HUMIDITY: 10 to 15 percent. * TEMPERATURES: Highs in the 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. && $$ 21
3 follow-up statements
655 WWUS85 KRIW 231039 RFWRIW URGENT - FIRE WEATHER MESSAGE National Weather Service Riverton WY 439 AM MDT Mon Aug 23 2021 WYZ280-281-285-289-240200- /O.CON.KRIW.FW.W.0014.210823T1800Z-210824T0200Z/ Natrona County/Casper BLM-Johnson County/Casper BLM- South Bighorn Mountains-Granite/Green/Ferris/Rattlesnake Mountains- 439 AM MDT Mon Aug 23 2021 ...RED FLAG WARNING REMAINS IN EFFECT FROM NOON TODAY TO 8 PM MDT THIS EVENING... * IMPACTS: Low Humidities and Strong Gusty Winds will create erratic fire behavior and new fire starts. * AFFECTED AREA: In Central WY Fire Zones...280...285...289. In North Central WY Fire Zone....281. * COUNTIES AFFECTED: In Central WY...Fremont...Natrona. In North Central WY...Hot Springs...Johnson...Washakie. In Southwest WY...Sweetwater. * WIND: Southwest 15 to 25 mph with gusts up to 40 mph. * HUMIDITY: As low as 13 percent. * TEMPERATURES: Highs in the mid 80s. PRECAUTIONARY/PREPAREDNESS ACTIONS... A Red Flag Warning means that critical fire weather conditions are either occurring now....or will shortly. A combination of strong winds...low relative humidity...and warm temperatures can contribute to extreme fire behavior. && $$ http://weather.gov/riverton
567 WWUS85 KRIW 231756 RFWRIW URGENT - FIRE WEATHER MESSAGE National Weather Service Riverton WY 1156 AM MDT Mon Aug 23 2021 WYZ280-281-285-289-240200- /O.CON.KRIW.FW.W.0014.210823T1800Z-210824T0200Z/ Natrona County/Casper BLM-Johnson County/Casper BLM- South Bighorn Mountains-Granite/Green/Ferris/Rattlesnake Mountains- 1156 AM MDT Mon Aug 23 2021 ...RED FLAG WARNING REMAINS IN EFFECT UNTIL 8 PM MDT THIS EVENING... * 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 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 15 to 25 mph with gusts up to 40 mph. * HUMIDITY: As low as 13 percent. * TEMPERATURES: Highs in the 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. && $$ 21
438 WWUS85 KRIW 240133 RFWRIW URGENT - FIRE WEATHER MESSAGE National Weather Service Riverton WY 733 PM MDT Mon Aug 23 2021 WYZ280-281-285-289-240245- /O.EXP.KRIW.FW.W.0014.000000T0000Z-210824T0200Z/ Natrona County/Casper BLM-Johnson County/Casper BLM- South Bighorn Mountains-Granite/Green/Ferris/Rattlesnake Mountains- 733 PM MDT Mon Aug 23 2021 ...RED FLAG WARNING WILL EXPIRE AT 8 PM MDT THIS EVENING... Winds have decreased this evening as relative humidities begin to recover; therefore, the Red Flag Warning will be allowed to expire. $$ http://weather.gov/riverton
The office that day
Everything else NWS Riverton, WY issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Aug 21, 7:14 PM MDT | Special Weather Statement | RIW | Lincoln | 31 min |
| Aug 21, 7:45 PM MDT | Special Weather Statement | RIW | Lincoln | 30 min |
| Aug 21, 8:24 PM MDT | Special Weather Statement | RIW | 36 min | |
| Aug 21, 8:51 PM MDT | Special Weather Statement | RIW | 24 min | |
| Aug 21, 9:11 PM MDT | Severe Thunderstorm Warning | RIW | Sublette, Sweetwater | 34 min |
| Aug 21, 9:42 PM MDT | Special Weather Statement | RIW | 33 min | |
| Aug 21, 10:06 PM MDT | Special Weather Statement | RIW | Fremont | 24 min |
| Aug 21, 10:30 PM MDT | Special Weather Statement | RIW | Fremont | 30 min |
| Aug 21, 10:36 PM MDT | Special Weather Statement | RIW | Hot Springs | 24 min |
| Aug 21, 10:59 PM MDT | Special Weather Statement | RIW | Washakie | 31 min |
| Aug 21, 11:03 PM MDT | Special Weather Statement | RIW | 27 min | |
| Aug 21, 11:42 PM MDT | Special Weather Statement | RIW | Natrona | 33 min |
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.