Alert archive / Colorado / Red Flag Warnings in 2021
Red Flag Warning 14, NWS Denver/Boulder, CO
NWS Denver/Boulder, CO issued this red flag warning at Sep 15, 2021, 2:31 PM MDT for 5 counties in Colorado. It took effect at Sep 16, 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
- Sep 15, 2021, 2:31 PM MDT (20:31 UTC)
- In effect from
- Sep 16, 2021, 12:00 PM MDT
- Expired
- Sep 16, 2021, 7:00 PM MDT
- In force
- 7 hr
- Issued by
- NWS Denver/Boulder, CO
Counties Boulder County, CO, Grand County, CO, Jackson County, CO, Larimer County, CO, Summit County, CO
The radar
The Denver radar (KFTG), 124 km from the middle of the area, began a volume at 20:31 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
Denver, CO (KDNR), launched 12:00Z, 8.5 hours before the alert went out and 229 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
- 2773 m above ground
- 0-6 km bulk shear
- 25 kt
- 0-1 km storm-relative helicity
- 77 m²/s²
- 0-3 km storm-relative helicity
- 128 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.0
The text
As transmitted.
319 WWUS85 KBOU 152031 RFWBOU URGENT - FIRE WEATHER MESSAGE National Weather Service Denver/Boulder CO 231 PM MDT Wed Sep 15 2021 ...Critical Fire Danger Thursday and Friday Afternoons... .Warm temperatures, low daytime humidity, and gusty winds will result in critical fire weather conditions during the afternoon and early evening hours Thursday and Friday. Mixing heights will also increase above 10,000 ft, increasing the potential for deep vertical plume growth in the event of any new starts. COZ211-213-217-218-161200- /O.NEW.KBOU.FW.W.0014.210916T1800Z-210917T0100Z/ /O.NEW.KBOU.FW.A.0012.210917T1800Z-210918T0100Z/ Jackson County Below 9000 Feet- Grand and Summit Counties Below 9000 Feet- West Jackson and West Grand Counties Above 9000 Feet- South and East Jackson/Larimer/North and Northeast Grand/ Northwest Boulder Counties Above 9000 Feet- 231 PM MDT Wed Sep 15 2021 ...RED FLAG WARNING IN EFFECT FROM NOON TO 7 PM MDT THURSDAY FOR WIND AND LOW RELATIVE HUMIDITY FOR MUCH OF JACKSON AND GRAND COUNTIES... ...FIRE WEATHER WATCH IN EFFECT FROM FRIDAY AFTERNOON THROUGH FRIDAY EVENING FOR WIND AND LOW RELATIVE HUMIDITY FOR MOUNTAINS AND HIGH VALLEYS... The National Weather Service in Denver has issued a Red Flag Warning for wind and low relative humidity, which is in effect from noon to 7 PM MDT Thursday. A Fire Weather Watch has also been issued. This Fire Weather Watch for wind and low relative humidity is in effect from Friday afternoon through Friday evening. * Affected Area...Fire Weather Zones 211, 213, 217 and 218. * Timing...Noon to 7 PM. Most critical conditions mid to late afternoon. * Winds...West/southwest 10 to 20 mph, with gusts to 30 mph. * Relative Humidity...10 to 18%. * Impacts...Conditions will be conducive to rapid spread of new and existing fires. Probability of ignition will increase. Avoid any burning or outdoor activities that may cause sparks, and abide by established fire restrictions. 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. A Fire Weather Watch means that critical fire weather conditions are forecast to occur. Listen for later forecasts and possible Red Flag Warnings. && $$ COZ212-214-161200- /O.NEW.KBOU.FW.A.0012.210917T1800Z-210918T0100Z/ South and Southeast Grand/West Central and Southwest Boulder/ Gilpin/Clear Creek/Summit/North and West Park Counties Above 9000 Feet-Central and Southeast Park County- 231 PM MDT Wed Sep 15 2021 ...FIRE WEATHER WATCH IN EFFECT FROM FRIDAY AFTERNOON THROUGH FRIDAY EVENING FOR WIND AND LOW RELATIVE HUMIDITY FOR THE MOUNTAINS AND HIGH VALLEYS... The National Weather Service in Denver has issued a Fire Weather Watch for wind and low relative humidity, which is in effect from Friday afternoon through Friday evening. * Affected Area...Fire Weather Zones 212 and 214. * Timing...Noon to 7 PM. Most critical conditions mid to late afternoon. * Winds...West 10 to 20 mph, with gusts to 30 mph. * Relative Humidity...Between 10 and 15%. * Impacts...Conditions will be conducive to rapid spread of new and existing fires. Probability of ignition will increase. Avoid any burning or outdoor activities that may cause sparks, and abide by established fire restrictions. PRECAUTIONARY/PREPAREDNESS ACTIONS... A Fire Weather Watch means that critical fire weather conditions are forecast to occur. Listen for later forecasts and possible Red Flag Warnings. && $$
3 follow-up statements
637 WWUS85 KBOU 161021 RFWBOU URGENT - FIRE WEATHER MESSAGE National Weather Service Denver/Boulder CO 421 AM MDT Thu Sep 16 2021 ...Critical Fire Danger Today and Friday Afternoons... .Warm temperatures, low daytime humidity, and gusty winds will result in critical fire weather conditions during the afternoon and early evening hours today and Friday. Mixing heights will also increase above 10,000 ft, increasing the potential for deep vertical plume growth in the event of any new starts. COZ211-213-217-218-170100- /O.CON.KBOU.FW.W.0014.210916T1800Z-210917T0100Z/ /O.CON.KBOU.FW.A.0012.210917T1800Z-210918T0100Z/ Jackson County Below 9000 Feet- Grand and Summit Counties Below 9000 Feet- West Jackson and West Grand Counties Above 9000 Feet- South and East Jackson/Larimer/North and Northeast Grand/ Northwest Boulder Counties Above 9000 Feet- 421 AM MDT Thu Sep 16 2021 ...RED FLAG WARNING REMAINS IN EFFECT FROM NOON TODAY TO 7 PM MDT THIS EVENING FOR WIND AND LOW RELATIVE HUMIDITY FOR MUCH OF JACKSON AND GRAND COUNTIES... ...FIRE WEATHER WATCH REMAINS IN EFFECT FROM FRIDAY AFTERNOON THROUGH FRIDAY EVENING FOR WIND AND LOW RELATIVE HUMIDITY FOR MOUNTAINS AND HIGH VALLEYS... * Affected Area...Fire Weather Zones 211, 213, 217 and 218. * Timing...Noon to 7 PM. Most critical conditions mid to late afternoon. * Winds...Southwest 10 to 20 mph with gusts up to 35 mph. * Relative Humidity...As low as 10 to 15 percent. * Impacts...Conditions will be conducive to rapid spread of new and existing fires. Probability of ignition will increase. Avoid any burning or outdoor activities that may cause sparks, and abide by established fire restrictions. 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. A Fire Weather Watch means that critical fire weather conditions are forecast to occur. Listen for later forecasts and possible Red Flag Warnings. && $$ COZ212-214-170100- /O.CON.KBOU.FW.A.0012.210917T1800Z-210918T0100Z/ South and Southeast Grand/West Central and Southwest Boulder/ Gilpin/Clear Creek/Summit/North and West Park Counties Above 9000 Feet-Central and Southeast Park County- 421 AM MDT Thu Sep 16 2021 ...FIRE WEATHER WATCH REMAINS IN EFFECT FROM FRIDAY AFTERNOON THROUGH FRIDAY EVENING FOR WIND AND LOW RELATIVE HUMIDITY FOR THE MOUNTAINS AND HIGH VALLEYS... * Affected Area...Fire Weather Zones 212 and 214. * Timing...Noon to 7 PM. Most critical conditions mid to late afternoon. * Winds...Southwest 10 to 20 mph with gusts up to 30 mph. * Relative Humidity...As low as 10 to 15 percent. * Impacts...Conditions will be conducive to rapid spread of new and existing fires. Probability of ignition will increase. Avoid any burning or outdoor activities that may cause sparks, and abide by established fire restrictions. PRECAUTIONARY/PREPAREDNESS ACTIONS... A Fire Weather Watch means that critical fire weather conditions are forecast to occur. Listen for later forecasts and possible Red Flag Warnings. && $$
099 WWUS85 KBOU 161809 RFWBOU URGENT - FIRE WEATHER MESSAGE National Weather Service Denver/Boulder CO 1209 PM MDT Thu Sep 16 2021 ...Critical Fire Danger Today and Friday Afternoon... .Warm temperatures, low daytime humidity, and gusty winds will result in critical fire weather conditions during the afternoon and early evening hours today and Friday. Mixing heights will also increase above 10,000 ft, increasing the potential for deep vertical plume growth in the event of any new starts. COZ211-213-217-218-170215- /O.CON.KBOU.FW.W.0014.000000T0000Z-210917T0100Z/ /O.CON.KBOU.FW.A.0012.210917T1800Z-210918T0100Z/ Jackson County Below 9000 Feet- Grand and Summit Counties Below 9000 Feet- West Jackson and West Grand Counties Above 9000 Feet- South and East Jackson/Larimer/North and Northeast Grand/ Northwest Boulder Counties Above 9000 Feet- 1209 PM MDT Thu Sep 16 2021 ...RED FLAG WARNING REMAINS IN EFFECT UNTIL 7 PM MDT THIS EVENING FOR WIND AND LOW RELATIVE HUMIDITY FOR MUCH OF JACKSON AND GRAND COUNTIES... ...FIRE WEATHER WATCH REMAINS IN EFFECT FROM FRIDAY AFTERNOON THROUGH FRIDAY EVENING FOR WIND AND LOW RELATIVE HUMIDITY FOR MOUNTAINS AND HIGH VALLEYS... * Affected Area...Fire Weather Zones 211, 213, 217 and 218. * Timing...Noon to 7 PM. Most critical conditions mid to late afternoon. * Winds...Southwest 10 to 20 mph with gusts up to 35 mph. * Relative Humidity...As low as 10 percent. * Impacts...Conditions will be conducive to rapid spread of new and existing fires. Probability of ignition will increase. Avoid any burning or outdoor activities that may cause sparks, and abide by established fire restrictions. 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. A Fire Weather Watch means that critical fire weather conditions are forecast to occur. Listen for later forecasts and possible Red Flag Warnings. && $$ COZ212-214-170215- /O.CON.KBOU.FW.A.0012.210917T1800Z-210918T0100Z/ South and Southeast Grand/West Central and Southwest Boulder/ Gilpin/Clear Creek/Summit/North and West Park Counties Above 9000 Feet-Central and Southeast Park County- 1209 PM MDT Thu Sep 16 2021 ...FIRE WEATHER WATCH REMAINS IN EFFECT FROM FRIDAY AFTERNOON THROUGH FRIDAY EVENING FOR WIND AND LOW RELATIVE HUMIDITY FOR THE MOUNTAINS AND HIGH VALLEYS... * Affected Area...Fire Weather Zones 212 and 214. * Timing...Noon to 7 PM. Most critical conditions mid to late afternoon. * Winds...Southwest 10 to 20 mph with gusts up to 30 mph. * Relative Humidity...As low as 10 to 15 percent. * Impacts...Conditions will be conducive to rapid spread of new and existing fires. Probability of ignition will increase. Avoid any burning or outdoor activities that may cause sparks, and abide by established fire restrictions. PRECAUTIONARY/PREPAREDNESS ACTIONS... A Fire Weather Watch means that critical fire weather conditions are forecast to occur. Listen for later forecasts and possible Red Flag Warnings. && $$
135 WWUS85 KBOU 162101 RFWBOU URGENT - FIRE WEATHER MESSAGE National Weather Service Denver/Boulder CO 301 PM MDT Thu Sep 16 2021 ...Critical Fire Danger Today and Friday Afternoon... .Warm temperatures, low daytime humidity, and gusty winds will result in critical fire weather conditions during the afternoon and early evening hours today and Friday. Mixing heights will also increase above 10,000 ft, increasing the potential for deep vertical plume growth in the event of any new starts. COZ212-214-162215- /O.CAN.KBOU.FW.A.0012.210917T1800Z-210918T0100Z/ South and Southeast Grand/West Central and Southwest Boulder/ Gilpin/Clear Creek/Summit/North and West Park Counties Above 9000 Feet-Central and Southeast Park County- 301 PM MDT Thu Sep 16 2021 ...FIRE WEATHER WATCH IS CANCELLED FOR WIND AND LOW RELATIVE HUMIDITY FOR THE CENTRAL MOUNTAINS AND SOUTH PARK... The National Weather Service in Denver has cancelled the Fire Weather Watch. There will be elevated fire danger across the central mountains and South Park but the winds will not be high enough to warrant a Red Flag Warning. $$ COZ211-213-217-218-170515- /O.CON.KBOU.FW.W.0014.000000T0000Z-210917T0100Z/ /O.CON.KBOU.FW.A.0012.210917T1800Z-210918T0100Z/ Jackson County Below 9000 Feet- Grand and Summit Counties Below 9000 Feet- West Jackson and West Grand Counties Above 9000 Feet- South and East Jackson/Larimer/North and Northeast Grand/ Northwest Boulder Counties Above 9000 Feet- 301 PM MDT Thu Sep 16 2021 ...RED FLAG WARNING REMAINS IN EFFECT UNTIL 7 PM MDT THIS EVENING FOR WIND AND LOW RELATIVE HUMIDITY FOR MUCH OF JACKSON AND GRAND COUNTIES... ...FIRE WEATHER WATCH REMAINS IN EFFECT FROM FRIDAY AFTERNOON THROUGH FRIDAY EVENING FOR WIND AND LOW RELATIVE HUMIDITY FOR MUCH OF JACKSON AND GRAND COUNTIES... * Affected Area...Fire Weather Zones 211, 213, 217 and 218. * Timing...Noon to 7 PM. Most critical conditions mid to late afternoon. * Winds...Southwest 10 to 20 mph with gusts up to 30 mph. * Relative Humidity...As low as 10 percent. * Impacts...Conditions will be conducive to rapid spread of new and existing fires. Probability of ignition will increase. Avoid any burning or outdoor activities that may cause sparks, and abide by established fire restrictions. PRECAUTIONARY/PREPAREDNESS ACTIONS... A Red Flag Warning means that critical fire weather conditions are either occurring now....or will shortly. A combination of strong winds...low relative humidity...and warm temperatures can contribute to extreme fire behavior. A Fire Weather Watch means that critical fire weather conditions are forecast to occur. Listen for later forecasts and possible Red Flag Warnings. && $$
The office that day
Everything else NWS Denver/Boulder, CO issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Sep 15, 6:37 AM MDT | Dense Fog Advisory | BOU | Elbert, Lincoln | 2 hr |
| Sep 15, 2:31 PM MDT | Fire Weather Watch | BOU | Boulder, Clear Creek, Gilpin, Grand, Jackson, Larimer and 2 more | 37 hr |
Nearby
Red Flag Warnings in Colorado, 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.