Alert archive / Colorado / Red Flag Warnings in 2021
Red Flag Warning 22, NWS Denver/Boulder, CO
NWS Denver/Boulder, CO issued this red flag warning at Nov 17, 2021, 2:16 PM MST for 9 counties in Colorado. It took effect at Nov 18, 2021, 10:00 AM MST. It was in force for 19 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
- Nov 17, 2021, 2:16 PM MST (21:16 UTC)
- In effect from
- Nov 18, 2021, 10:00 AM MST
- Expired
- Nov 19, 2021, 5:00 AM MST
- In force
- 19 hr
- Issued by
- NWS Denver/Boulder, CO
Counties Arapahoe County, CO, Boulder County, CO, Clear Creek County, CO, Douglas County, CO, Elbert County, CO, Gilpin County, CO, Jefferson County, CO, Larimer County, CO, Park County, CO
The radar
The Denver radar (KFTG), 53 km from the middle of the area, began a volume at 21:20 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, 9.3 hours before the alert went out and 165 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
- 994 m above ground
- 0-6 km bulk shear
- 72 kt
- 0-1 km storm-relative helicity
- 101 m²/s²
- 0-3 km storm-relative helicity
- 337 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.0
The text
As transmitted.
795 WWUS85 KBOU 172116 RFWBOU URGENT - FIRE WEATHER MESSAGE National Weather Service Denver/Boulder CO 216 PM MST Wed Nov 17 2021 ...DANGEROUS FIRE WEATHER LIKELY OVER THE EAST SLOPES OF THE FRONT RANGE THURSDAY AND THURSDAY NIGHT... .Very dry air will be over northern Colorado Thursday, with humidities of 5-10% possible in the Front Range foothills. Winds will increase during the day, and it will remain dry and windy overnight Thursday night with little cooling. Conditions are expected to improve Friday morning and humidities increase, but it will still be dry and windy on Friday. COZ214-241-180530- /O.UPG.KBOU.FW.A.0017.211118T1900Z-211119T0100Z/ /O.NEW.KBOU.FW.W.0022.211118T1700Z-211119T0600Z/ Central and Southeast Park County- Elbert/Central and East Douglas Counties Above 6000 Feet- 216 PM MST Wed Nov 17 2021 ...RED FLAG WARNING IN EFFECT FROM 10 AM TO 11 PM MST THURSDAY FOR WIND AND LOW RELATIVE HUMIDITY FOR SOUTH PARK AND EASTERN DOUGLAS AND WESTERN ELBERT COUNTIES...FIRE ZONES 214 AND 241... The National Weather Service in Denver has issued a Red Flag Warning for wind and low relative humidity, which is in effect from 10 AM to 11 PM MST Thursday. The Fire Weather Watch is no longer in effect. * Affected Area...Fire Weather Zones 214 and 241. * Timing...Very dry air will be over the area Thursday morning. Winds will increase in the afternoon. Conditions will improve with increasing humidities Thursday evening, though it will remain breezy in Douglas and Elbert counties overnight. * Winds...Southwest 10 to 20 mph with gusts up to 35 mph. * Relative Humidity...As low as 6 percent. * Impacts...Any fires that start will have the potential to spread rapidly. 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. && $$ COZ215-216-180530- /O.UPG.KBOU.FW.A.0017.211118T1700Z-211119T1200Z/ /O.NEW.KBOU.FW.W.0022.211118T1700Z-211119T1200Z/ Larimer and Boulder Counties Between 6000 and 9000 Feet- Jefferson and West Douglas Counties Above 6000 Feet/Gilpin/Clear Creek/Northeast Park Counties Below 9000 Feet- 216 PM MST Wed Nov 17 2021 ...RED FLAG WARNING IN EFFECT FROM 10 AM THURSDAY TO 5 AM MST FRIDAY FOR WIND AND LOW RELATIVE HUMIDITY FOR THE FRONT RANGE FOOTHILLS...FIRE WEATHER ZONES 215 AND 216... The National Weather Service in Denver has issued a Red Flag Warning for wind and low relative humidity, which is in effect from 10 AM Thursday to 5 AM MST Friday. The Fire Weather Watch is no longer in effect. * Affected Area...Fire Weather Zones 215 and 216. * Timing...Very dry air will be over the area Thursday morning. Winds will increase during the day and continue Thursday night, with poor humidity recovery expected until late at night. * Winds...Southwest 15 to 25 mph with gusts up to 40 mph. * Relative Humidity...As low as 7 percent. * Impacts...Any fire that starts will have the potential to spread rapidly. Extreme fire behavior will be possible. PRECAUTIONARY/PREPAREDNESS ACTIONS... A Red Flag Warning means that critical fire weather conditions are either occurring now....or will shortly. A combination of strong winds...low relative humidity...and warm temperatures can contribute to extreme fire behavior. && $$
5 follow-up statements
437 WWUS85 KBOU 180342 RFWBOU URGENT - FIRE WEATHER MESSAGE National Weather Service Denver/Boulder CO 842 PM MST Wed Nov 17 2021 ...DANGEROUS FIRE WEATHER LIKELY OVER THE EAST SLOPES OF THE FRONT RANGE THURSDAY AND THURSDAY NIGHT... .Very dry air will be over northern Colorado Thursday, with humidities of 5-10% possible in the Front Range foothills. Winds will increase during the day, and it will remain dry and windy overnight Thursday night with little cooling. Conditions are expected to improve Friday morning and humidities increase, but it will still be dry and windy on Friday. COZ214-241-181300- /O.CON.KBOU.FW.W.0022.211118T1700Z-211119T0600Z/ Central and Southeast Park County- Elbert/Central and East Douglas Counties Above 6000 Feet- 842 PM MST Wed Nov 17 2021 ...RED FLAG WARNING REMAINS IN EFFECT FROM 10 AM TO 11 PM MST THURSDAY FOR WIND AND LOW RELATIVE HUMIDITY FOR SOUTH PARK AND EASTERN DOUGLAS AND WESTERN ELBERT COUNTIES...FIRE ZONES 214 AND 241... * Affected Area...Fire Weather Zones 214 and 241. * Timing...Very dry air will be over the area Thursday morning. Winds will increase in the afternoon. Conditions will improve with increasing humidities Thursday evening, though it will remain breezy in Douglas and Elbert counties overnight. * Winds...Southwest 10 to 20 mph with gusts up to 35 mph. * Relative Humidity...As low as 6 percent. * Impacts...Any fires that start will have the potential to spread rapidly. 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. && $$ COZ215-216-181300- /O.CON.KBOU.FW.W.0022.211118T1700Z-211119T1200Z/ Larimer and Boulder Counties Between 6000 and 9000 Feet- Jefferson and West Douglas Counties Above 6000 Feet/Gilpin/Clear Creek/Northeast Park Counties Below 9000 Feet- 842 PM MST Wed Nov 17 2021 ...RED FLAG WARNING REMAINS IN EFFECT FROM 10 AM THURSDAY TO 5 AM MST FRIDAY FOR WIND AND LOW RELATIVE HUMIDITY FOR THE FRONT RANGE FOOTHILLS...FIRE WEATHER ZONES 215 AND 216... * Affected Area...Fire Weather Zones 215 and 216. * Timing...Very dry air will be over the area Thursday morning. Winds will increase during the day and continue Thursday night, with poor humidity recovery expected until late at night. * Winds...Southwest 15 to 25 mph with gusts up to 40 mph. * Relative Humidity...As low as 7 percent. * Impacts...Any fire that starts will have the potential to spread rapidly. Extreme fire behavior will be possible. PRECAUTIONARY/PREPAREDNESS ACTIONS... A Red Flag Warning means that critical fire weather conditions are either occurring now....or will shortly. A combination of strong winds...low relative humidity...and warm temperatures can contribute to extreme fire behavior. && $$
715 WWUS85 KBOU 181211 RFWBOU URGENT - FIRE WEATHER MESSAGE National Weather Service Denver/Boulder CO 511 AM MST Thu Nov 18 2021 ...DANGEROUS FIRE WEATHER LIKELY OVER THE EAST SLOPES OF THE FRONT RANGE THIS AFTERNOON AND TONIGHT... .Very dry air will surface across northern Colorado today, with humidities of 5-10% possible in the Front Range foothills. Winds will mainly be above 9000 feet this morning, but will become more widespread this afternoon and then stronger this evening. It will remain dry and windy overnight in the foothills with little cooling. Conditions are expected to improve Friday morning and humidities increase, but it will still be dry and windy on Friday. COZ214-241-182015- /O.CON.KBOU.FW.W.0022.211118T1700Z-211119T0600Z/ Central and Southeast Park County- Elbert/Central and East Douglas Counties Above 6000 Feet- 511 AM MST Thu Nov 18 2021 ...RED FLAG WARNING REMAINS IN EFFECT FROM 10 AM THIS MORNING TO 11 PM MST THIS EVENING FOR WIND AND LOW RELATIVE HUMIDITY FOR SOUTH PARK AND EASTERN DOUGLAS AND WESTERN ELBERT COUNTIES...FIRE ZONES 214 AND 241... * Affected Area...Fire Weather Zones 214 and 241. * Timing...Very low humidities will become widespread this morning. Winds will increase in the afternoon. Conditions will improve with increasing humidities Thursday evening, though it will remain breezy in Douglas and Elbert counties overnight. * Winds...Southwest 10 to 20 mph with gusts up to 30 mph. * Relative Humidity...As low as 5 percent. * Impacts...Any fires that start will have the potential to spread rapidly. 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. && $$ COZ215-216-182015- /O.CON.KBOU.FW.W.0022.211118T1700Z-211119T1200Z/ Larimer and Boulder Counties Between 6000 and 9000 Feet- Jefferson and West Douglas Counties Above 6000 Feet/Gilpin/Clear Creek/Northeast Park Counties Below 9000 Feet- 511 AM MST Thu Nov 18 2021 ...RED FLAG WARNING REMAINS IN EFFECT FROM 10 AM THIS MORNING TO 5 AM MST FRIDAY FOR WIND AND LOW RELATIVE HUMIDITY FOR THE FRONT RANGE FOOTHILLS...FIRE WEATHER ZONES 215 AND 216... * Affected Area...Fire Weather Zones 215 and 216. * Timing...Very dry air will become widespread this morning. West winds will gradually increase today and become stronger this evening. Poor humidity recovery is expected until late tonight. * Winds...Becoming southwest 10 to 20 mph today, then west 15 to 25 mph with gusts up to 40 mph tonight. * Relative Humidity...As low as 6 percent. * Impacts...Any fire that starts will have the potential to spread rapidly. Extreme fire behavior will be possible. PRECAUTIONARY/PREPAREDNESS ACTIONS... A Red Flag Warning means that critical fire weather conditions are either occurring now....or will shortly. A combination of strong winds...low relative humidity...and warm temperatures can contribute to extreme fire behavior. && $$ Gimmestad
791 WWUS85 KBOU 182007 RFWBOU URGENT - FIRE WEATHER MESSAGE National Weather Service Denver/Boulder CO 107 PM MST Thu Nov 18 2021 ...DANGEROUS FIRE WEATHER LIKELY OVER THE EAST SLOPES OF THE FRONT RANGE THIS AFTERNOON AND TONIGHT... .Very dry air will surface across northern Colorado today, with humidities of 5-10% possible in the Front Range foothills. Winds will mainly be above 9000 feet this morning, but will become more widespread this afternoon and then stronger this evening. It will remain dry and windy overnight in the foothills with little cooling. Conditions are expected to improve Friday morning and humidities increase, but it will still be dry and windy on Friday. COZ214-241-190500- /O.CON.KBOU.FW.W.0022.000000T0000Z-211119T0600Z/ Central and Southeast Park County- Elbert/Central and East Douglas Counties Above 6000 Feet- 107 PM MST Thu Nov 18 2021 ...RED FLAG WARNING REMAINS IN EFFECT UNTIL 11 PM MST THIS EVENING FOR WIND AND LOW RELATIVE HUMIDITY FOR SOUTH PARK AND EASTERN DOUGLAS AND WESTERN ELBERT COUNTIES...FIRE ZONES 214 AND 241... * Affected Area...Fire Weather Zones 214 and 241. * Timing...Very low humidities will become widespread this morning. Winds will increase in the afternoon. Conditions will improve with increasing humidities Thursday evening, though it will remain breezy in Douglas and Elbert counties overnight. * Winds...Southwest 10 to 20 mph with gusts up to 35 mph. * Relative Humidity...As low as 5 percent. * Impacts...Any fires that start will have the potential to spread rapidly. 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. && $$ COZ215-216-190500- /O.CON.KBOU.FW.W.0022.000000T0000Z-211119T1200Z/ Larimer and Boulder Counties Between 6000 and 9000 Feet- Jefferson and West Douglas Counties Above 6000 Feet/Gilpin/Clear Creek/Northeast Park Counties Below 9000 Feet- 107 PM MST Thu Nov 18 2021 ...RED FLAG WARNING REMAINS IN EFFECT UNTIL 5 AM MST FRIDAY FOR WIND AND LOW RELATIVE HUMIDITY FOR THE FRONT RANGE FOOTHILLS... FIRE WEATHER ZONES 215 AND 216... * Affected Area...Fire Weather Zones 215 and 216. * Timing...Very dry air will become widespread this morning. West winds will gradually increase today and become stronger this evening. Poor humidity recovery is expected until late tonight. * Winds...Southwest 10 to 20 mph with gusts up to 40 mph. * Relative Humidity...As low as 6 percent. * Impacts...Any fire that starts will have the potential to spread rapidly. Extreme fire behavior will be possible. PRECAUTIONARY/PREPAREDNESS ACTIONS... A Red Flag Warning means that critical fire weather conditions are either occurring now....or will shortly. A combination of strong winds...low relative humidity...and warm temperatures can contribute to extreme fire behavior. && $$
517 WWUS85 KBOU 190604 RFWBOU URGENT - FIRE WEATHER MESSAGE National Weather Service Denver/Boulder CO 1104 PM MST Thu Nov 18 2021 ...RED FLAG WARNING CONTINUES OVERNIGHT FOR THE FRONT RANGE FOOTHILLS... .Very dry air remains over northern Colorado this evening, with humidities of 10-15% in the Front Range foothills. Winds have been sporadic, but wind prone areas and the higher foothills have mostly had winds of 15-25 mph. Some increase in speeds and coverage of the winds is expected overnight, with a gradual increase in the humidities. A further increase in humidities is expected on Friday, but it will still be dry and windy with conditions near Red Flag criteria. COZ214-241-190715- /O.EXP.KBOU.FW.W.0022.000000T0000Z-211119T0600Z/ Central and Southeast Park County- Elbert/Central and East Douglas Counties Above 6000 Feet- 1104 PM MST Thu Nov 18 2021 ...RED FLAG WARNING WILL EXPIRE AT 11 PM MST THIS EVENING FOR WIND AND LOW RELATIVE HUMIDITY FOR SOUTH PARK AND EASTERN DOUGLAS AND WESTERN ELBERT COUNTIES...FIRE ZONES 214 AND 241... Humidities remain low in these areas and will slowly increase overnight. Winds will generally be under 15 mph. $$ COZ215-216-191200- /O.CON.KBOU.FW.W.0022.000000T0000Z-211119T1200Z/ Larimer and Boulder Counties Between 6000 and 9000 Feet- Jefferson and West Douglas Counties Above 6000 Feet/Gilpin/Clear Creek/Northeast Park Counties Below 9000 Feet- 1104 PM MST Thu Nov 18 2021 ...RED FLAG WARNING REMAINS IN EFFECT UNTIL 5 AM MST FRIDAY FOR WIND AND LOW RELATIVE HUMIDITY FOR THE FRONT RANGE FOOTHILLS... FIRE WEATHER ZONES 215 AND 216... * Affected Area...Fire Weather Zones 215 and 216. * Timing...West winds will gradually become more widespread and a bit stronger overnight, with humidities gradually increasing. * Winds...Southwest 10 to 20 mph with gusts up to 40 mph in wind prone and higher foothills areas. * Relative Humidity...As low as 10 percent. * Impacts...Any fire that starts will have the potential to spread rapidly. Extreme fire behavior will be possible. PRECAUTIONARY/PREPAREDNESS ACTIONS... A Red Flag Warning means that critical fire weather conditions are either occurring now....or will shortly. A combination of strong winds...low relative humidity...and warm temperatures can contribute to extreme fire behavior. && $$ Gimmestad
782 WWUS85 KBOU 191157 RFWBOU URGENT - FIRE WEATHER MESSAGE National Weather Service Denver/Boulder CO 457 AM MST Fri Nov 19 2021 COZ215-216-191300- /O.EXP.KBOU.FW.W.0022.000000T0000Z-211119T1200Z/ Larimer and Boulder Counties Between 6000 and 9000 Feet- Jefferson and West Douglas Counties Above 6000 Feet/Gilpin/Clear Creek/Northeast Park Counties Below 9000 Feet- 457 AM MST Fri Nov 19 2021 ...RED FLAG WARNING WILL EXPIRE AT 5 AM MST... Humidities have increased and moisture will continue to move into the area on west winds today. It will remain windy over the foothills today, especially above 7500 feet and in wind prone spots in the lower foothills. These areas will have occasional gusts in the 30 to 40 mph range. Humidities will still be low, but not as extreme as yesterday with readings generally between 15 and 25 percent. With high to very high fire danger in the foothills, use of fire outdoors is still discouraged today. $$ Gimmestad
The office that day
Everything else NWS Denver/Boulder, CO issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Nov 17, 4:58 AM MST | Fire Weather Watch | BOU | Arapahoe, Boulder, Clear Creek, Douglas, Elbert, Gilpin and 3 more | 9 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.