Alert archive / Colorado / Red Flag Warnings in 2021
Red Flag Warning 17, NWS Denver/Boulder, CO
NWS Denver/Boulder, CO issued this red flag warning at Oct 25, 2021, 4:01 AM MDT for 6 counties in Colorado. It took effect at Oct 25, 2021, 12:00 PM MDT. It was in force for 6 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
- Oct 25, 2021, 4:01 AM MDT (10:01 UTC)
- In effect from
- Oct 25, 2021, 12:00 PM MDT
- Expired
- Oct 25, 2021, 6:00 PM MDT
- In force
- 6 hr
- Issued by
- NWS Denver/Boulder, CO
Counties Adams County, CO, Arapahoe County, CO, Broomfield County, CO, Denver County, CO, Douglas County, CO, Elbert County, CO
The radar
The Denver radar (KFTG), 17 km from the middle of the area, began a volume at 10:01 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 00:00Z, 10.0 hours before the alert went out and 121 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
- 2827 m above ground
- 0-6 km bulk shear
- 55 kt
- 0-1 km storm-relative helicity
- 59 m²/s²
- 0-3 km storm-relative helicity
- 197 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.0
The text
As transmitted.
321 WWUS85 KBOU 251001 RFWBOU URGENT - FIRE WEATHER MESSAGE National Weather Service Denver/Boulder CO 401 AM MDT Mon Oct 25 2021 COZ240-241-245-251800- /O.UPG.KBOU.FW.A.0016.211025T1800Z-211026T0000Z/ /O.NEW.KBOU.FW.W.0017.211025T1800Z-211026T0000Z/ North Douglas County Below 6000 Feet/Denver/West Adams and Arapahoe Counties/East Broomfield County- Elbert/Central and East Douglas Counties Above 6000 Feet- Central and East Adams and Arapahoe Counties- 401 AM MDT Mon Oct 25 2021 ...RED FLAG WARNING IN EFFECT FROM NOON TODAY TO 6 PM MDT THIS EVENING FOR WIND AND LOW RELATIVE HUMIDITY FOR FIRE WEATHER ZONES...240...241 AND 245. THIS INCLUDES PORTIONS OF THE PALMER DIVIDE, DENVER AND EASTERN PORTIONS OF ADAMS AND ARAPAHOE COUNTIES... The National Weather Service in Denver has issued a Red Flag Warning for wind and low relative humidity, which is in effect from noon today to 6 PM MDT this evening. The Fire Weather Watch is no longer in effect. * Affected Area...Fire Weather Zones 240, 241 and 245. * Timing...Today from noon to 6 PM. * Winds...South 15 to 25 mph with gusts up to 35 mph. * Relative Humidity...As low as 14 percent. * Impacts...Conditions will be conducive to the rapid spread of new 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. && $$
2 follow-up statements
037 WWUS85 KBOU 251616 RFWBOU URGENT - FIRE WEATHER MESSAGE National Weather Service Denver/Boulder CO 1016 AM MDT Mon Oct 25 2021 COZ240-241-245-260000- /O.CON.KBOU.FW.W.0017.211025T1800Z-211026T0000Z/ North Douglas County Below 6000 Feet/Denver/West Adams and Arapahoe Counties/East Broomfield County- Elbert/Central and East Douglas Counties Above 6000 Feet- Central and East Adams and Arapahoe Counties- 1016 AM MDT Mon Oct 25 2021 ...RED FLAG WARNING REMAINS IN EFFECT UNTIL 6 PM MDT THIS EVENING FOR WIND AND LOW RELATIVE HUMIDITY FOR FIRE WEATHER ZONES...240... 241 AND 245. THIS INCLUDES PORTIONS OF THE PALMER DIVIDE, DENVER AND EASTERN PORTIONS OF ADAMS AND ARAPAHOE COUNTIES... * Affected Area...Fire Weather Zones 240, 241 and 245. * Timing...Today from noon to 6 PM. * Winds...South 15 to 25 mph with gusts up to 35 mph. * Relative Humidity...As low as 15 percent. * Impacts...Conditions will be conducive to the rapid spread of new fires. Probability of ignition will increase. Avoid any burning or outdoor activities that may cause sparks, and abide by established fire restrictions. PRECAUTIONARY/PREPAREDNESS ACTIONS... A Red Flag Warning means that critical fire weather conditions are either occurring now....or will shortly. A combination of strong winds...low relative humidity...and warm temperatures can contribute to extreme fire behavior. && $$
862 WWUS85 KBOU 252348 RFWBOU URGENT - FIRE WEATHER MESSAGE National Weather Service Denver/Boulder CO 548 PM MDT Mon Oct 25 2021 ...RED FLAG WARNING WILL EXPIRE FOR WINDS AND LOW RELATIVE HUMIDITY FOR FIRE WEATHER ZONES...240...241 AND 245... COZ240-241-245-260100- /O.EXP.KBOU.FW.W.0017.000000T0000Z-211026T0000Z/ North Douglas County Below 6000 Feet/Denver/West Adams and Arapahoe Counties/East Broomfield County- Elbert/Central and East Douglas Counties Above 6000 Feet- Central and East Adams and Arapahoe Counties- 548 PM MDT Mon Oct 25 2021 ...RED FLAG WARNING WILL EXPIRE AT 6 PM MDT THIS EVENING FOR WIND AND LOW RELATIVE HUMIDITY FOR FIRE WEATHER ZONES...240...241 AND 245. THIS INCLUDES PORTIONS OF THE PALMER DIVIDE, DENVER AND EASTERN PORTIONS OF ADAMS AND ARAPAHOE COUNTIES... Current observations show relative humidity percentages ranging from 28-35 across fire weather zones 240, 241, and 245. Although gusty winds will continue, the Red Flag Warning will be allowed to expire due to recovering humidity levels above warning criteria. $$
The office that day
Everything else NWS Denver/Boulder, CO issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Oct 25, 3:02 PM MDT | Winter Weather Advisory | BOU | Grand, Jackson | 33 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.