Alert archive / Colorado / Red Flag Warnings in 2021

Red Flag Warning 8, NWS Denver/Boulder, CO

April 25, 20216 counties in Colorado

NWS Denver/Boulder, CO issued this red flag warning at Apr 25, 2021, 1:53 PM MDT for 6 counties in Colorado. It took effect at Apr 26, 2021, 9:00 AM MDT. It was in force for 11 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
Apr 25, 2021, 1:53 PM MDT (19:53 UTC)
In effect from
Apr 26, 2021, 9:00 AM MDT
Expired
Apr 26, 2021, 8:00 PM MDT
In force
11 hr
Issued by
NWS Denver/Boulder, CO

Counties Elbert County, CO, Lincoln County, CO, Logan County, CO, Phillips County, CO, Sedgwick County, CO, Washington County, CO

The radar

The Denver radar (KFTG), 126 km from the middle of the area, began a volume at 19:50 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, 7.9 hours before the alert went out and 25 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 2021-04-25Temperature 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 2021-04-25The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 36 square meters per square second.19395878Sfc1 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
2208 m above ground
0-6 km bulk shear
45 kt
0-1 km storm-relative helicity
36 m²/s²
0-3 km storm-relative helicity
255 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

778 
WWUS85 KBOU 251953
RFWBOU

URGENT - FIRE WEATHER MESSAGE
National Weather Service Denver/Boulder CO
153 PM MDT Sun Apr 25 2021

...ELEVATED FIRE DANGER THIS AFTERNOON AND MONDAY ON THE EASTERN 
PLAINS...

.Warm, dry, and windy conditions will increase the fire danger
over the eastern Colorado plains. The strongest winds will be
southeast and east of Denver both afternoons. On Monday the winds
will pick up earlier, with Red Flag conditions likely before noon.
Over the northeast corner of Colorado, the strength of the winds 
are less certain so the Fire Weather Watch will remain in effect 
for those areas for Monday. Over the western portion of the plains
closer to Denver the weather conditions will be similar, but the
fuels are beginning to green up in response to the rain and snow
that has fallen recently.

COZ246-247-261100-
/O.UPG.KBOU.FW.A.0005.210426T1500Z-210427T0200Z/
/O.NEW.KBOU.FW.W.0008.210426T1500Z-210427T0200Z/
/O.CON.KBOU.FW.W.0007.000000T0000Z-210426T0200Z/
North and Northeast Elbert County Below 6000 Feet/North Lincoln
County-
Southeast Elbert County Below 6000 Feet/South Lincoln County-
153 PM MDT Sun Apr 25 2021

...RED FLAG WARNING REMAINS IN EFFECT UNTIL 8 PM MDT THIS EVENING
FOR WIND AND LOW RELATIVE HUMIDITY...
...RED FLAG WARNING IN EFFECT FROM 9 AM TO 8 PM MDT MONDAY FOR 
WIND AND LOW RELATIVE HUMIDITY...

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 8 PM MDT Monday. A Red Flag Warning also remains in
effect through 8 PM today.

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

* Timing...Sunday noon to 8 PM, then Monday late morning through 
  early evening.

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

* Relative Humidity...As low as 6 percent.

* Impacts...Strong winds combined with low relative humidity may 
  cause new fire starts to rapidly spread and grow.

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.

&&

$$

COZ248>251-261100-
/O.CON.KBOU.FW.A.0005.210426T1500Z-210427T0200Z/
Logan County-Washington County-Sedgwick County-Phillips County-
153 PM MDT Sun Apr 25 2021

...FIRE WEATHER WATCH REMAINS IN EFFECT FROM MONDAY MORNING
THROUGH MONDAY EVENING FOR WIND AND LOW RELATIVE HUMIDITY...

* Affected Area...Fire Weather Zones 248, 249, 250 and 251.

* Timing...Monday late morning through early evening.

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

* Relative Humidity...As low as 7 percent.

* Impacts...Strong winds combined with low relative humidity may 
  cause new fire starts to rapidly spread and grow.

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.

&&

$$

Gimmestad
4 follow-up statements
801 
WWUS85 KBOU 260206
RFWBOU

URGENT - FIRE WEATHER MESSAGE
National Weather Service Denver/Boulder CO
806 PM MDT Sun Apr 25 2021

...ELEVATED FIRE DANGER MONDAY ON THE EASTERN PLAINS...

.On Monday the winds will pick up in the morning, with Red Flag 
conditions likely before noon. Over the northeast corner of 
Colorado, the strength of the winds are less certain so the Fire 
Weather Watch will remain in effect for those areas for Monday. 
Over the western portion of the plains closer to Denver the 
weather conditions will be similar, but the fuels are beginning to
green up in response to the rain and snow that has fallen 
recently.

COZ246-247-261015-
/O.EXP.KBOU.FW.W.0007.000000T0000Z-210426T0200Z/
/O.CON.KBOU.FW.W.0008.210426T1500Z-210427T0200Z/
North and Northeast Elbert County Below 6000 Feet/North Lincoln
County-
Southeast Elbert County Below 6000 Feet/South Lincoln County-
806 PM MDT Sun Apr 25 2021

...RED FLAG WARNING REMAINS IN EFFECT FROM 9 AM TO 8 PM MDT
MONDAY FOR WIND AND LOW RELATIVE HUMIDITY...

...RED FLAG WARNING HAS EXPIRED TODAY AND THIS EVENING FOR WIND 
AND LOW RELATIVE HUMIDITY...

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

* Timing...Sunday noon to 8 PM, then Monday late morning through 
  early evening.

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

* Relative Humidity...As low as 6 percent.

* Impacts...Strong winds combined with low relative humidity may 
  cause new fire starts to rapidly spread and grow.

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.

&&

$$

COZ248>251-261015-
/O.CON.KBOU.FW.A.0005.210426T1500Z-210427T0200Z/
Logan County-Washington County-Sedgwick County-Phillips County-
806 PM MDT Sun Apr 25 2021

...FIRE WEATHER WATCH REMAINS IN EFFECT FROM MONDAY MORNING
THROUGH MONDAY EVENING FOR WIND AND LOW RELATIVE HUMIDITY...

* Affected Area...Fire Weather Zones 248, 249, 250 and 251.

* Timing...Monday late morning through early evening.

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

* Relative Humidity...As low as 7 percent.

* Impacts...Strong winds combined with low relative humidity may 
  cause new fire starts to rapidly spread and grow.

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.

&&

$$
281 
WWUS85 KBOU 260912
RFWBOU

URGENT - FIRE WEATHER MESSAGE
National Weather Service Denver/Boulder CO
312 AM MDT Mon Apr 26 2021

...ELEVATED FIRE DANGER MONDAY ON THE EASTERN PLAINS...

.Winds will increase this morning, with Red Flag conditions 
likely before noon. Over the northeast corner of Colorado, the 
strength of the winds will be a little weaker, but some gusts to
25 mph will likely accompany the very low relative humidities 
today. Over the western portion of the plains, closer to Denver 
the weather conditions will be similar, but the fuels are 
beginning to green up in response to the recent rain and snow.

COZ248>251-262200-
/O.UPG.KBOU.FW.A.0005.210426T1500Z-210427T0200Z/
/O.EXA.KBOU.FW.W.0008.210426T1500Z-210427T0200Z/
Logan County-Washington County-Sedgwick County-Phillips County-
312 AM MDT Mon Apr 26 2021

...RED FLAG WARNING IN EFFECT FROM 9 AM THIS MORNING TO 8 PM MDT
THIS EVENING FOR WIND AND LOW RELATIVE HUMIDITY FOR THE NORTHEAST
CORNER OF COLORADO...

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 8 PM MDT this evening. The Fire Weather
Watch is no longer in effect.

* Affected Area...Fire Weather Zones 248, 249, 250 and 251.

* Timing...Monday late morning through early evening.

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

* Relative Humidity...As low as 7 percent.

* Impacts...Strong winds combined with low relative humidity may 
  cause new fire starts to rapidly spread and grow.

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.

&&

$$

COZ246-247-262200-
/O.CON.KBOU.FW.W.0008.210426T1500Z-210427T0200Z/
North and Northeast Elbert County Below 6000 Feet/North Lincoln
County-
Southeast Elbert County Below 6000 Feet/South Lincoln County-
312 AM MDT Mon Apr 26 2021

...RED FLAG WARNING REMAINS IN EFFECT FROM 9 AM THIS MORNING TO
8 PM MDT THIS EVENING FOR WIND AND LOW RELATIVE HUMIDITY FOR
LINCOLN COUNTY AND EASTERN ELBERT COUNTY...

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

* Timing...Sunday noon to 8 PM, then Monday late morning through 
  early evening.

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

* Relative Humidity...As low as 6 percent.

* Impacts...Strong winds combined with low relative humidity may 
  cause new fire starts to rapidly spread and grow.

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.

&&

$$
043 
WWUS85 KBOU 262108
RFWBOU

URGENT - FIRE WEATHER MESSAGE
National Weather Service Denver/Boulder CO
308 PM MDT Mon Apr 26 2021

...CRITICAL FIRE WEATHER CONDITIONS CONTINUE INTO EARLY THIS
EVENING ON THE EASTERN PLAINS...

COZ250-251-262215-
/O.CAN.KBOU.FW.W.0008.000000T0000Z-210427T0200Z/
Sedgwick County-Phillips County-
308 PM MDT Mon Apr 26 2021

...RED FLAG WARNING IS CANCELLED FOR WIND AND LOW RELATIVE
HUMIDITY FOR SEDGWICK AND PHILLIPS COUNTIES...FIRE WEATHER ZONES 
250 AND 251...

The National Weather Service in Denver has cancelled the Red Flag
Warning.

Humidity is low, with readings 10 to 15 percent, however, winds 
did not get strong enough, and are not expected to for the rest of
the afternoon and early evening. Gusts will only be in the 12 to
18 mph range. 

$$

COZ246>249-270200-
/O.CON.KBOU.FW.W.0008.000000T0000Z-210427T0200Z/
North and Northeast Elbert County Below 6000 Feet/North Lincoln
County-
Southeast Elbert County Below 6000 Feet/South Lincoln County-
Logan County-Washington County-
308 PM MDT Mon Apr 26 2021

...RED FLAG WARNING REMAINS IN EFFECT UNTIL 8 PM MDT THIS EVENING
FOR WIND AND LOW RELATIVE HUMIDITY FOR THE NORTHEASTERN PLAINS
INCLUDING LOGAN...WASHINGTON...LINCOLN AND EASTERN ELBERT COUNTIES...

* Affected Area...Fire Weather Zones 246, 247, 248 and 249.

* Timing...Until early this evening.

* Winds...South 10 to 20 mph with gusts up to 30 mph, strongest
  along and south of I-70.

* Relative Humidity...As low as 5 percent, except as low as 12
  percent for Logan County.

* Impacts...Strong winds combined with low relative humidity may 
  cause new fire starts to rapidly spread and grow.

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.

&&

$$
133 
WWUS85 KBOU 270158
RFWBOU

URGENT - FIRE WEATHER MESSAGE
National Weather Service Denver/Boulder CO
758 PM MDT Mon Apr 26 2021

COZ246>249-270300-
/O.EXP.KBOU.FW.W.0008.000000T0000Z-210427T0200Z/
North and Northeast Elbert County Below 6000 Feet/North Lincoln
County-
Southeast Elbert County Below 6000 Feet/South Lincoln County-
Logan County-Washington County-
758 PM MDT Mon Apr 26 2021

...RED FLAG WARNING WILL EXPIRE AT 8 PM MDT THIS EVENING FOR WIND
AND LOW RELATIVE HUMIDITY FOR THE NORTHEASTERN PLAINS INCLUDING
LOGAN...WASHINGTON...LINCOLN AND EASTERN ELBERT COUNTIES...

Humidity levels have increased with decreasing wind so the Red
Flag Warning has been allowed to expire.

$$

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.