Alert archive / Colorado / Red Flag Warnings in 2021

Red Flag Warning 23, NWS Denver/Boulder, CO

November 22, 202116 counties in Colorado

NWS Denver/Boulder, CO issued this red flag warning at Nov 22, 2021, 2:40 PM MST for 16 counties in Colorado. It took effect at Nov 23, 2021, 9:00 AM MST. 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
Nov 22, 2021, 2:40 PM MST (21:40 UTC)
In effect from
Nov 23, 2021, 9:00 AM MST
Expired
Nov 23, 2021, 5:00 PM MST
In force
8 hr
Issued by
NWS Denver/Boulder, CO

Counties Adams County, CO, Arapahoe County, CO, Boulder County, CO, Broomfield County, CO, Clear Creek County, CO, Denver County, CO, Douglas County, CO, Elbert County, CO, Gilpin County, CO, Grand County, CO, Jackson County, CO, Jefferson County, CO, Larimer County, CO, Park County, CO, Summit County, CO, Weld County, CO

The radar

The Denver radar (KFTG), 59 km from the middle of the area, began a volume at 21:38 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, 9.7 hours before the alert went out and 170 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.

Skew-T log-pSkew-T log-p diagram, Denver, CO at 12:00Z on 2021-11-22Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 0 joules per kilogram.LCL10008507005003002001001 km2 km3 km6 km9 km12 km-30°-20°-10°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Denver, CO at 12:00Z on 2021-11-22The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 159 square meters per square second.193958Sfc1 km3 km6 km9 kmRMLM
The wind turning with height, colored by layer: ground to 1 km, 1 to 3 km, 3 to 6 km, 6 to 10 km.
Mixed-layer CAPE
0 J/kg
Mixed-layer CIN
No buoyant parcel
Mixed-layer LCL
3522 m above ground
0-6 km bulk shear
45 kt
0-1 km storm-relative helicity
159 m²/s²
0-3 km storm-relative helicity
176 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

625 
WWUS85 KBOU 222140
RFWBOU

URGENT - FIRE WEATHER MESSAGE
National Weather Service Denver/Boulder CO
240 PM MST Mon Nov 22 2021

...DANGEROUS FIRE WEATHER CONDITIONS EXPECTED TUESDAY OVER THE 
FRONT RANGE FOOTHILLS, PALMER DIVIDE, SOUTH PARK, AND PORTIONS OF 
THE URBAN CORRIDOR...FIRE ZONES 214, 215, 216, 238, 239, 242, 
246, AND 247...

COZ214>216-238-239-241-242-230545-
/O.UPG.KBOU.FW.A.0018.211123T1800Z-211124T0000Z/
/O.NEW.KBOU.FW.W.0023.211123T1600Z-211124T0000Z/
Central and Southeast Park County-
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-
Larimer County Below 6000 Feet/Northwest Weld County-
Boulder And Jefferson Counties Below 6000 Feet/West Broomfield
County-Elbert/Central and East Douglas Counties Above 6000 Feet-
Northeast Weld County-
240 PM MST Mon Nov 22 2021

...RED FLAG WARNING IN EFFECT FROM 9 AM TO 5 PM MST TUESDAY FOR
WIND AND LOW RELATIVE HUMIDITY FOR THE FRONT RANGE FOOTHILLS,
SOUTH PARK, PALMER DIVIDE, AND PORTIONS OF THE I-25 URBAN
CORRIDOR...FIRE WEATHER ZONES 214...215...216...238...239...241...
AND 242...

The National Weather Service in Denver has issued a Red Flag 
Warning for wind and low relative humidity, which is in effect 
from 9 AM to 5 PM MST Tuesday. The Fire Weather Watch is no longer
in effect.

* Affected Area...Fire Weather Zones 214, 215, 216, 238, 239, 
  241 and 242.

* Timing...9 AM to 5 PM MST Tuesday evening.

* Winds...West 20 to 30 mph with gusts up to 45 mph. Strongest
  winds in the foothills. 

* Relative Humidity...As low as 10 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.

&&

$$

COZ246-247-230545-
/O.CON.KBOU.FW.A.0018.211123T1800Z-211124T0000Z/
North and Northeast Elbert County Below 6000 Feet/North Lincoln
County-
Southeast Elbert County Below 6000 Feet/South Lincoln County-
240 PM MST Mon Nov 22 2021

...FIRE WEATHER WATCH REMAINS IN EFFECT FROM TUESDAY MORNING
THROUGH TUESDAY AFTERNOON FOR WIND AND LOW RELATIVE HUMIDITY FOR
EASTERN ELBERT AND LINCOLN COUNTIES...FIRE WEATHER ZONES 246 AND
247...

* Affected Area...Fire Weather Zones 246 and 247.

* Timing...11 AM to 5 PM MST Tuesday evening.

* Winds...West 15 to 20 mph with gusts up to 30 mph.

* Relative Humidity...As low as 8 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 Fire Weather Watch means that critical fire weather conditions
are forecast to occur. Listen for later forecasts and possible
Red Flag Warnings.

&&

$$
5 follow-up statements
115 
WWUS85 KBOU 230310
RFWBOU

URGENT - FIRE WEATHER MESSAGE
National Weather Service Denver/Boulder CO
810 PM MST Mon Nov 22 2021

...DANGEROUS FIRE WEATHER CONDITIONS EXPECTED TUESDAY OVER THE
FRONT RANGE FOOTHILLS, PALMER DIVIDE, SOUTH PARK, AND PORTIONS OF
THE URBAN CORRIDOR...FIRE ZONES 214, 215, 216, 238, 239, 242,
246, AND 247...

COZ214>216-238-239-241-242-231115-
/O.CON.KBOU.FW.W.0023.211123T1600Z-211124T0000Z/
Central and Southeast Park County-
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-
Larimer County Below 6000 Feet/Northwest Weld County-
Boulder And Jefferson Counties Below 6000 Feet/West Broomfield
County-Elbert/Central and East Douglas Counties Above 6000 Feet-
Northeast Weld County-
810 PM MST Mon Nov 22 2021

...RED FLAG WARNING REMAINS IN EFFECT FROM 9 AM TO 5 PM MST
TUESDAY FOR WIND AND LOW RELATIVE HUMIDITY FOR THE FRONT RANGE
FOOTHILLS, SOUTH PARK, PALMER DIVIDE, AND PORTIONS OF THE
I-25 URBAN CORRIDOR...FIRE WEATHER ZONES 214...215...216...238...
239...241...AND 242...

* Affected Area...Fire Weather Zones 214, 215, 216, 238, 239, 
  241 and 242.

* Timing...9 AM to 5 PM MST Tuesday evening.

* Winds...West 15 to 25 mph with gusts up to 40 mph.

* Relative Humidity...As low as 9 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.

&&

$$

COZ246-247-231115-
/O.CON.KBOU.FW.A.0018.211123T1800Z-211124T0000Z/
North and Northeast Elbert County Below 6000 Feet/North Lincoln
County-
Southeast Elbert County Below 6000 Feet/South Lincoln County-
810 PM MST Mon Nov 22 2021

...FIRE WEATHER WATCH REMAINS IN EFFECT FROM TUESDAY MORNING
THROUGH TUESDAY AFTERNOON FOR WIND AND LOW RELATIVE HUMIDITY FOR
EASTERN ELBERT AND LINCOLN COUNTIES...FIRE WEATHER ZONES 246 AND
247...

* Affected Area...Fire Weather Zones 246 and 247.

* Timing...11 AM to 5 PM MST Tuesday evening.

* Winds...West 10 to 20 mph with gusts up to 30 mph.

* Relative Humidity...As low as 7 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 Fire Weather Watch means that critical fire weather conditions
are forecast to occur. Listen for later forecasts and possible
Red Flag Warnings.

&&

$$
820 
WWUS85 KBOU 231018
RFWBOU

URGENT - FIRE WEATHER MESSAGE
National Weather Service Denver/Boulder CO
318 AM MST Tue Nov 23 2021

...DANGEROUS FIRE WEATHER CONDITIONS EXPECTED TODAY OVER THE 
FRONT RANGE FOOTHILLS, PALMER DIVIDE, SOUTH PARK, AND PORTIONS OF 
THE URBAN CORRIDOR...FIRE ZONES 214, 215, 216, 238, 239, 240, 242,
246, AND 247...

COZ246-247-231130-
/O.CAN.KBOU.FW.A.0018.211123T1800Z-211124T0000Z/
North and Northeast Elbert County Below 6000 Feet/North Lincoln
County-
Southeast Elbert County Below 6000 Feet/South Lincoln County-
318 AM MST Tue Nov 23 2021

...FIRE WEATHER WATCH IS CANCELLED FOR WIND AND LOW RELATIVE
HUMIDITY FOR EASTERN ELBERT AND LINCOLN COUNTIES...FIRE WEATHER
ZONES 246 AND 247...

The National Weather Service in Denver has cancelled the Fire
Weather Watch.

It will be very dry today with relative humidity falling below 10
percent. However, winds are expected to be less than 25 mph so the
Fire Weather Watch has been canceled.

$$

COZ240-231900-
/O.EXA.KBOU.FW.W.0023.211123T1600Z-211124T0000Z/
North Douglas County Below 6000 Feet/Denver/West Adams and
Arapahoe Counties/East Broomfield County-
318 AM MST Tue Nov 23 2021

...RED FLAG WARNING IN EFFECT FROM 9 AM THIS MORNING TO 5 PM MST
THIS AFTERNOON FOR WIND AND LOW RELATIVE HUMIDITY FOR DENVER METRO
AREA...

The National Weather Service in Denver has issued a Red Flag
Warning for wind and low relative humidity, which is in effect
from 9 AM this morning to 5 PM MST this afternoon.

* Affected Area...Fire Weather Zone 240.

* Timing...9 AM to 5 PM MST today.

* Winds...West 10 to 20 mph with gusts up to 35 mph.

* Relative Humidity...As low as 8 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.

&&

$$

COZ214>216-238-239-241-242-231900-
/O.CON.KBOU.FW.W.0023.211123T1600Z-211124T0000Z/
Central and Southeast Park County-
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-
Larimer County Below 6000 Feet/Northwest Weld County-
Boulder And Jefferson Counties Below 6000 Feet/West Broomfield
County-Elbert/Central and East Douglas Counties Above 6000 Feet-
Northeast Weld County-
318 AM MST Tue Nov 23 2021

...RED FLAG WARNING REMAINS IN EFFECT FROM 9 AM THIS MORNING TO
5 PM MST THIS AFTERNOON FOR WIND AND LOW RELATIVE HUMIDITY FOR
THE FRONT RANGE FOOTHILLS, SOUTH PARK, PALMER DIVIDE, AND
PORTIONS OF THE I-25 URBAN CORRIDOR...FIRE WEATHER ZONES 214...
215...216...238...239...241...AND 242...

* Affected Area...Fire Weather Zones 214, 215, 216, 238, 239, 
  241 and 242.

* Timing...9 AM to 5 PM MST today.

* Winds...West 15 to 25 mph with gusts up to 45 mph.

* Relative Humidity...As low as 8 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.

&&

$$
742 
WWUS85 KBOU 231851
RFWBOU

URGENT - FIRE WEATHER MESSAGE
National Weather Service Denver/Boulder CO
1151 AM MST Tue Nov 23 2021

...DANGEROUS FIRE WEATHER CONDITIONS EXPECTED TODAY OVER THE
FRONT RANGE FOOTHILLS, PALMER DIVIDE, HIGH MOUNTAIN VALLEYS, AND 
PORTIONS OF THE URBAN CORRIDOR...FIRE ZONES 211, 213, 214, 215, 
216, 238, 239, 240, 241, 242, 246, AND 247...

COZ211-213-240000-
/O.EXA.KBOU.FW.W.0023.000000T0000Z-211124T0000Z/
Jackson County Below 9000 Feet-
Grand and Summit Counties Below 9000 Feet-
1151 AM MST Tue Nov 23 2021

...RED FLAG WARNING IN EFFECT UNTIL 5 PM MST THIS AFTERNOON FOR
WIND AND LOW RELATIVE HUMIDITY FOR NORTH AND MIDDLE PARK...

The National Weather Service in Denver has issued a Red Flag
Warning for wind and low relative humidity, which is in effect
until 5 PM MST this afternoon.

* Affected Area...Fire Weather Zones 211 and 213.

* Timing...9 AM to 5 PM MST today.

* Winds...Southwest 15 to 25 mph with gusts up to 40 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.

&&

$$

COZ214>216-238>242-240000-
/O.CON.KBOU.FW.W.0023.000000T0000Z-211124T0000Z/
Central and Southeast Park County-
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-
Larimer County Below 6000 Feet/Northwest Weld County-
Boulder And Jefferson Counties Below 6000 Feet/West Broomfield
County-
North Douglas County Below 6000 Feet/Denver/West Adams and
Arapahoe Counties/East Broomfield County-
Elbert/Central and East Douglas Counties Above 6000 Feet-
Northeast Weld County-
1151 AM MST Tue Nov 23 2021

...RED FLAG WARNING REMAINS IN EFFECT UNTIL 5 PM MST THIS
AFTERNOON FOR WIND AND LOW RELATIVE HUMIDITY FOR SOUTH PARK, FRONT
RANGE FOOTHILLS, I-25 CORRIDOR...

* Affected Area...Fire Weather Zones 214, 215, 216, 238, 239, 
  240, 241 and 242.

* Timing...9 AM to 5 PM MST today.

* Winds...West 15 to 25 mph with gusts up to 45 mph.

* Relative Humidity...As low as 7 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.

&&

$$
764 
WWUS85 KBOU 232159
RFWBOU

URGENT - FIRE WEATHER MESSAGE
National Weather Service Denver/Boulder CO
259 PM MST Tue Nov 23 2021

...DANGEROUS FIRE WEATHER CONDITIONS EXPECTED THROUGH LATE
AFTERNOON OVER THE FRONT RANGE FOOTHILLS, PALMER DIVIDE, HIGH 
MOUNTAIN VALLEYS, AND PORTIONS OF THE URBAN CORRIDOR...FIRE ZONES 
211, 213 THROUGH 216...AND 238 THROUGH 242...

COZ211-213>216-238>242-240000-
/O.CON.KBOU.FW.W.0023.000000T0000Z-211124T0000Z/
Jackson County Below 9000 Feet-
Grand and Summit Counties Below 9000 Feet-
Central and Southeast Park County-
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-
Larimer County Below 6000 Feet/Northwest Weld County-
Boulder And Jefferson Counties Below 6000 Feet/West Broomfield
County-
North Douglas County Below 6000 Feet/Denver/West Adams and
Arapahoe Counties/East Broomfield County-
Elbert/Central and East Douglas Counties Above 6000 Feet-
Northeast Weld County-
259 PM MST Tue Nov 23 2021

...RED FLAG WARNING REMAINS IN EFFECT UNTIL 5 PM MST THIS
AFTERNOON FOR WIND AND LOW RELATIVE HUMIDITY FOR SOUTH PARK,
FRONT RANGE FOOTHILLS, I-25 CORRIDOR...

* Affected Area...Fire Weather Zones 211, 213, 214, 215, 216, 
  238, 239, 240, 241 and 242.

* Timing...until 5 PM MST today.

* Winds...West 10 to 20 mph with gusts up to 35 mph.

* Relative Humidity...As low as 7 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.

&&

$$
841 
WWUS85 KBOU 240019
RFWBOU

URGENT - FIRE WEATHER MESSAGE
National Weather Service Denver/Boulder CO
519 PM MST Tue Nov 23 2021

COZ211-213>216-238>242-240130-
/O.EXP.KBOU.FW.W.0023.000000T0000Z-211124T0000Z/
Jackson County Below 9000 Feet-
Grand and Summit Counties Below 9000 Feet-
Central and Southeast Park County-
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-
Larimer County Below 6000 Feet/Northwest Weld County-
Boulder And Jefferson Counties Below 6000 Feet/West Broomfield
County-
North Douglas County Below 6000 Feet/Denver/West Adams and
Arapahoe Counties/East Broomfield County-
Elbert/Central and East Douglas Counties Above 6000 Feet-
Northeast Weld County-
519 PM MST Tue Nov 23 2021

...RED FLAG WARNING HAS EXPIRED FOR WIND AND LOW RELATIVE
HUMIDITY FOR SOUTH PARK, FRONT RANGE FOOTHILLS, I-25 CORRIDOR...

Winds have decreased and relative humidity has increased above
15%. Therefore, the Red Flag Warning was allowed to expire.

$$

The office that day

Everything else NWS Denver/Boulder, CO issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Nov 22, 2:17 AM MSTFire Weather WatchBOUArapahoe, Boulder, Broomfield, Clear Creek, Douglas, Elbert and 6 more25 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.