Alert archive / Wyoming / Red Flag Warnings in 2021
Red Flag Warning 9, NWS Riverton, WY
NWS Riverton, WY issued this red flag warning at Aug 5, 2021, 2:03 PM MDT for 5 counties in Wyoming. It took effect at Aug 6, 2021, 12:00 PM MDT. It was in force for 8 hr. 3 reports 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
- Aug 5, 2021, 2:03 PM MDT (20:03 UTC)
- In effect from
- Aug 6, 2021, 12:00 PM MDT
- Expired
- Aug 6, 2021, 8:00 PM MDT
- In force
- 8 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 20:05 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
| Time | Report | Where | Remark |
|---|---|---|---|
| Aug 6, 4:07 PM MDT | TSTM WND GST 52 | Riverton, WY | RIVERTON, WY ASOS |
| Aug 6, 4:07 PM MDT | TSTM WND GST 60 | Riverton, WY | RIVERTON, WY ASOS |
| Aug 6, 4:10 PM MDT | HAIL 1 | Ethete, WY |
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 12:00Z, 8.1 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.
- Mixed-layer CAPE
- 0 J/kg
- Mixed-layer CIN
- No buoyant parcel
- Mixed-layer LCL
- 2896 m above ground
- 0-6 km bulk shear
- 19 kt
- 0-1 km storm-relative helicity
- -2 m²/s²
- 0-3 km storm-relative helicity
- 75 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.0
The text
As transmitted.
920 WWUS85 KRIW 052003 RFWRIW URGENT - FIRE WEATHER MESSAGE National Weather Service Riverton WY 203 PM MDT Thu Aug 5 2021 WYZ277-279-280-289-061200- /O.UPG.KRIW.FW.A.0005.210806T1800Z-210807T0200Z/ /O.NEW.KRIW.FW.W.0009.210806T1800Z-210807T0200Z/ Lincoln and Uinta Counties/Lower Elevations- Sweetwater County/Rock Springs BLM/Flaming Gorge NRA- Natrona County/Casper BLM- Granite/Green/Ferris/Rattlesnake Mountains- 203 PM MDT Thu Aug 5 2021 ...RED FLAG WARNING IN EFFECT FROM NOON TO 8 PM MDT FRIDAY... The National Weather Service in Riverton has issued a Red Flag Warning, which is in effect from noon to 8 PM MDT Friday. The Fire Weather Watch is no longer in effect. * IMPACTS: Low Humidities and Strong Gusty Winds will create erratic fire behavior and new fire starts. * AFFECTED AREA: In Central WY Fire Zones...280...289. In Southwest WY Fire Zones...277...279. * COUNTIES AFFECTED: In Central WY...Fremont...Natrona. In Southwest WY...Sweetwater...Uinta. In West Central WY...Lincoln. * WIND: West 20 to 30 mph with gusts up to 45 mph. Winds shift from west-southwest to west-northwest during the evening hours. * HUMIDITY: As low as 13 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. && $$ http://weather.gov/riverton
2 follow-up statements
504 WWUS85 KRIW 060859 RFWRIW URGENT - FIRE WEATHER MESSAGE National Weather Service Riverton WY 259 AM MDT Fri Aug 6 2021 WYZ277-279-280-289-070200- /O.CON.KRIW.FW.W.0009.210806T1800Z-210807T0200Z/ Lincoln and Uinta Counties/Lower Elevations- Sweetwater County/Rock Springs BLM/Flaming Gorge NRA- Natrona County/Casper BLM- Granite/Green/Ferris/Rattlesnake Mountains- 259 AM MDT Fri Aug 6 2021 ...RED FLAG WARNING REMAINS IN EFFECT FROM NOON TODAY TO 8 PM MDT THIS EVENING... * IMPACTS: Low Humidities and Strong Gusty Winds will create erratic fire behavior and new fire starts. * AFFECTED AREA: In Central WY Fire Zones...280...289. In Southwest WY Fire Zones...277...279. * COUNTIES AFFECTED: In Central WY...Fremont...Natrona. In Southwest WY...Sweetwater...Uinta. In West Central WY...Lincoln. * WIND: West 20 to 30 mph with gusts up to 45 mph. * HUMIDITY: 15 to 20 percent. PRECAUTIONARY/PREPAREDNESS ACTIONS... A Red Flag Warning means that critical fire weather conditions are either occurring now....or will shortly. A combination of strong winds...low relative humidity...and warm temperatures can contribute to extreme fire behavior. && $$ http://weather.gov/riverton
387 WWUS85 KRIW 070146 RFWRIW URGENT - FIRE WEATHER MESSAGE National Weather Service Riverton WY 746 PM MDT Fri Aug 6 2021 WYZ277-279-280-289-070300- /O.EXP.KRIW.FW.W.0009.000000T0000Z-210807T0200Z/ Lincoln and Uinta Counties/Lower Elevations- Sweetwater County/Rock Springs BLM/Flaming Gorge NRA- Natrona County/Casper BLM- Granite/Green/Ferris/Rattlesnake Mountains- 746 PM MDT Fri Aug 6 2021 ...RED FLAG WARNING WILL EXPIRE AT 8 PM MDT THIS EVENING... Increasing relative humidities and decreasing winds have occurred across the warned zones; 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 4, 8:05 PM MDT | Special Weather Statement | RIW | Natrona | 25 min |
| Aug 4, 8:25 PM MDT | Severe Thunderstorm Warning | RIW | Natrona | 50 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; local storm reports from the same archive; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.