Red Flag Warning 37, NWS Denver/Boulder, CO

477 
WWUS85 KBOU 211118
RFWBOU

URGENT - FIRE WEATHER MESSAGE
National Weather Service Denver/Boulder CO
518 AM MDT Tue Apr 21 2026

COZ214>216-238>251-220530-
/O.CON.KBOU.FW.W.0037.260422T1600Z-260423T0600Z/
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-Central and South Weld County-Morgan County-
Central and East Adams and Arapahoe Counties-
North and Northeast Elbert County Below 6000 Feet/North Lincoln
County-
Southeast Elbert County Below 6000 Feet/South Lincoln County-
Logan County-Washington County-Sedgwick County-Phillips County-
518 AM MDT Tue Apr 21 2026

...RED FLAG WARNING REMAINS IN EFFECT FROM 10 AM WEDNESDAY TO
MIDNIGHT MDT WEDNESDAY NIGHT FOR WIND AND LOW RELATIVE HUMIDITY
FOR THE FRONT RANGE FOOTHILLS, URBAN CORRIDOR, PLAINS, AND SOUTH
PARK...

* AFFECTED AREA...Fire Weather Zones 214, 215, 216, 238, 239, 
  240, 241, 242, 243, 244, 245, 246, 247, 248, 249, 250 and 251.

* TIMING...From 10 AM Wednesday to midnight MDT Wednesday night.

* WINDS...Southwest 20 to 30 mph with gusts up to 45 mph.

* RELATIVE HUMIDITY...As low as 6 percent.

* IMPACTS...Conditions will be favorable for rapid fire spread. 
  Avoid outdoor burning and any activity that may produce a 
  spark and start a wildfire.

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.

&&

$$

948 
WWUS85 KBOU 211915
RFWBOU

URGENT - FIRE WEATHER MESSAGE
National Weather Service Denver/Boulder CO
115 PM MDT Tue Apr 21 2026

COZ214-216-238>251-220615-
/O.NEW.KBOU.FW.A.0028.260423T1600Z-260424T0200Z/
/O.CON.KBOU.FW.W.0037.260422T1600Z-260423T0600Z/
Central and Southeast Park County-
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-Central and South Weld County-Morgan County-
Central and East Adams and Arapahoe Counties-
North and Northeast Elbert County Below 6000 Feet/North Lincoln
County-
Southeast Elbert County Below 6000 Feet/South Lincoln County-
Logan County-Washington County-Sedgwick County-Phillips County-
115 PM MDT Tue Apr 21 2026

...RED FLAG WARNING REMAINS IN EFFECT FROM 10 AM WEDNESDAY TO
MIDNIGHT MDT WEDNESDAY NIGHT FOR WIND AND LOW RELATIVE HUMIDITY
FOR THE FRONT RANGE FOOTHILLS, URBAN CORRIDOR, PLAINS, AND SOUTH
PARK...
...FIRE WEATHER WATCH IN EFFECT FROM THURSDAY MORNING THROUGH
THURSDAY EVENING FOR WIND AND LOW RELATIVE HUMIDITY FOR SOUTHERN
FOOTHILLS, URBAN CORRIDOR, PLAINS, AND SOUTH PARK...

The National Weather Service in Denver has issued a Fire Weather
Watch for wind and low relative humidity, which is in effect from
Thursday morning through Thursday evening.

* AFFECTED AREA...Fire Weather Zones 214, 216, 238, 239, 240, 
  241, 242, 243, 244, 245, 246, 247, 248, 249, 250 and 251.

* TIMING...For the Red Flag Warning, from 10 AM Wednesday to 
  midnight MDT Wednesday night. For the Fire Weather Watch, from 
  Thursday morning through Thursday evening.

* WINDS...For the Red Flag Warning, west 20 to 30 mph with gusts 
  up to 45 mph. For the Fire Weather Watch, northwest winds 
  gusting up to 50 mph.

* RELATIVE HUMIDITY...For the Red Flag Warning, 5 to 8 percent.
  For the Fire Weather Watch, as low as 10 percent.

* IMPACTS...Conditions will be favorable for rapid fire spread. 
  Avoid outdoor burning and any activity that may produce a 
  spark and start a wildfire.

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.

&&

$$

COZ215-220615-
/O.CON.KBOU.FW.W.0037.260422T1600Z-260423T0600Z/
Larimer and Boulder Counties Between 6000 and 9000 Feet-
115 PM MDT Tue Apr 21 2026

...RED FLAG WARNING REMAINS IN EFFECT FROM 10 AM WEDNESDAY TO
MIDNIGHT MDT WEDNESDAY NIGHT FOR WIND AND LOW RELATIVE HUMIDITY
FOR THE FRONT RANGE FOOTHILLS, URBAN CORRIDOR, PLAINS, AND SOUTH
PARK...

* AFFECTED AREA...Fire Weather Zone 215.

* TIMING...From 10 AM Wednesday to midnight MDT Wednesday night.

* WINDS...West 20 to 30 mph with gusts up to 45 mph.

* RELATIVE HUMIDITY...5 to 8 percent.

* IMPACTS...Conditions will be favorable for rapid fire spread. 
  Avoid outdoor burning and any activity that may produce a 
  spark and start a wildfire.

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.

&&

$$

273 
WWUS85 KBOU 220553
RFWBOU

URGENT - FIRE WEATHER MESSAGE
National Weather Service Denver/Boulder CO
1153 PM MDT Tue Apr 21 2026


COZ214-216-238>251-222100-
/O.CON.KBOU.FW.W.0037.260422T1600Z-260423T0600Z/
/O.CON.KBOU.FW.A.0028.260423T1600Z-260424T0200Z/
Central and Southeast Park County-
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-Central and South Weld County-Morgan County-
Central and East Adams and Arapahoe Counties-
North and Northeast Elbert County Below 6000 Feet/North Lincoln
County-
Southeast Elbert County Below 6000 Feet/South Lincoln County-
Logan County-Washington County-Sedgwick County-Phillips County-
1153 PM MDT Tue Apr 21 2026

...RED FLAG WARNING REMAINS IN EFFECT FROM 10 AM WEDNESDAY TO
MIDNIGHT MDT WEDNESDAY NIGHT FOR WIND AND LOW RELATIVE HUMIDITY
FOR THE FRONT RANGE FOOTHILLS, URBAN CORRIDOR, PLAINS, AND SOUTH
PARK...
...FIRE WEATHER WATCH REMAINS IN EFFECT FROM THURSDAY MORNING
THROUGH THURSDAY EVENING FOR WIND AND LOW RELATIVE HUMIDITY FOR
SOUTHERN FOOTHILLS, URBAN CORRIDOR, PLAINS, AND SOUTH PARK...

* AFFECTED AREA...Fire Weather Zones 214, 216, 238, 239, 240, 
  241, 242, 243, 244, 245, 246, 247, 248, 249, 250 and 251.

* TIMING...For the Red Flag Warning, from 10 AM Wednesday to 
  midnight MDT Wednesday night. For the Fire Weather Watch, from 
  Thursday morning through Thursday evening.

* WINDS...For the Red Flag Warning, west 20 to 30 mph with gusts 
  up to 45 mph. For the Fire Weather Watch, northwest winds 
  gusting up to 50 mph.

* RELATIVE HUMIDITY...For the Red Flag Warning, 5 to 8 percent.
  For the Fire Weather Watch, as low as 10 percent.

* IMPACTS...Conditions will be favorable for rapid fire spread. 
  Avoid outdoor burning and any activity that may produce a 
  spark and start a wildfire.

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.

&&

$$

COZ215-222100-
/O.CON.KBOU.FW.W.0037.260422T1600Z-260423T0600Z/
Larimer and Boulder Counties Between 6000 and 9000 Feet-
1153 PM MDT Tue Apr 21 2026

...RED FLAG WARNING REMAINS IN EFFECT FROM 10 AM WEDNESDAY TO
MIDNIGHT MDT WEDNESDAY NIGHT FOR WIND AND LOW RELATIVE HUMIDITY
FOR THE FRONT RANGE FOOTHILLS, URBAN CORRIDOR, PLAINS, AND SOUTH
PARK...

* AFFECTED AREA...Fire Weather Zone 215.

* TIMING...From 10 AM Wednesday to midnight MDT Wednesday night.

* WINDS...West 20 to 30 mph with gusts up to 45 mph.

* RELATIVE HUMIDITY...5 to 8 percent.

* IMPACTS...Conditions will be favorable for rapid fire spread. 
  Avoid outdoor burning and any activity that may produce a 
  spark and start a wildfire.

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.

&&

$$

579 
WWUS85 KBOU 221822
RFWBOU

URGENT - FIRE WEATHER MESSAGE
National Weather Service Denver/Boulder CO
1222 PM MDT Wed Apr 22 2026


COZ214-216-238>251-230230-
/O.UPG.KBOU.FW.A.0028.260423T1600Z-260424T0200Z/
/O.NEW.KBOU.FW.W.0038.260423T1700Z-260424T0100Z/
/O.CON.KBOU.FW.W.0037.000000T0000Z-260423T0600Z/
Central and Southeast Park County-
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-Central and South Weld County-Morgan County-
Central and East Adams and Arapahoe Counties-
North and Northeast Elbert County Below 6000 Feet/North Lincoln
County-
Southeast Elbert County Below 6000 Feet/South Lincoln County-
Logan County-Washington County-Sedgwick County-Phillips County-
1222 PM MDT Wed Apr 22 2026

...RED FLAG WARNING REMAINS IN EFFECT UNTIL MIDNIGHT MDT TONIGHT
FOR WIND AND LOW RELATIVE HUMIDITY FOR THE FRONT RANGE FOOTHILLS,
URBAN CORRIDOR, PLAINS, AND SOUTH PARK...

...RED FLAG WARNING IN EFFECT FROM 11 AM TO 7 PM MDT THURSDAY FOR
WIND AND LOW RELATIVE HUMIDITY FOR THE SOUTHERN FRONT RANGE
FOOTHILLS, URBAN CORRIDOR, PLAINS, AND SOUTH PARK...

The National Weather Service in Denver has issued a Red Flag
Warning for wind and low relative humidity, which is in effect
from 11 AM to 7 PM MDT Thursday. The Fire Weather Watch is no
longer in effect.

* AFFECTED AREA...Fire Weather Zones 214, 216, 238, 239, 240, 
  241, 242, 243, 244, 245, 246, 247, 248, 249, 250 and 251.

* TIMING...For the first Red Flag Warning, until midnight MDT 
  tonight. For the second Red Flag Warning, from 11 AM to 7 PM 
  MDT Thursday.

* WINDS...West 20 to 30 mph with gusts up to 45 mph. For the
  second Red Flag Warning, northwest winds gusting up to 50 mph.

* RELATIVE HUMIDITY...As low as 6 percent. For the second Red Flag
  Warning, as low as 10 percent.

* IMPACTS...Conditions will be favorable for rapid fire spread. 
  Avoid outdoor burning and any activity that may produce a 
  spark and start a wildfire.

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.

&&

$$

COZ215-230230-
/O.CON.KBOU.FW.W.0037.000000T0000Z-260423T0600Z/
Larimer and Boulder Counties Between 6000 and 9000 Feet-
1222 PM MDT Wed Apr 22 2026

...RED FLAG WARNING REMAINS IN EFFECT UNTIL MIDNIGHT MDT TONIGHT
FOR WIND AND LOW RELATIVE HUMIDITY FOR THE FRONT RANGE FOOTHILLS,
URBAN CORRIDOR, PLAINS, AND SOUTH PARK...

* AFFECTED AREA...Fire Weather Zone 215.

* TIMING...Until midnight MDT tonight.

* WINDS...West 20 to 30 mph with gusts up to 50 mph.

* RELATIVE HUMIDITY...As low as 9 percent.

* IMPACTS...Conditions will be favorable for rapid fire spread. 
  Avoid outdoor burning and any activity that may produce a 
  spark and start a wildfire.

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.

&&

$$

218 
WWUS85 KBOU 230244
RFWBOU

URGENT - FIRE WEATHER MESSAGE
National Weather Service Denver/Boulder CO
844 PM MDT Wed Apr 22 2026

COZ214-216-238>251-231045-
/O.CON.KBOU.FW.W.0037.000000T0000Z-260423T0600Z/
/O.CON.KBOU.FW.W.0038.260423T1700Z-260424T0100Z/
Central and Southeast Park County-
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-Central and South Weld County-Morgan County-
Central and East Adams and Arapahoe Counties-
North and Northeast Elbert County Below 6000 Feet/North Lincoln
County-
Southeast Elbert County Below 6000 Feet/South Lincoln County-
Logan County-Washington County-Sedgwick County-Phillips County-
844 PM MDT Wed Apr 22 2026

...RED FLAG WARNING REMAINS IN EFFECT UNTIL MIDNIGHT MDT TONIGHT
FOR WIND AND LOW RELATIVE HUMIDITY FOR THE SOUTHERN FRONT RANGE 
FOOTHILLS, URBAN CORRIDOR, PLAINS, AND SOUTH PARK... 
...RED FLAG WARNING REMAINS IN EFFECT FROM 11 AM TO 7 PM MDT 
THURSDAY FOR WIND AND LOW RELATIVE HUMIDITY FOR THE SOUTHERN 
FRONT RANGE FOOTHILLS, URBAN CORRIDOR, PLAINS, AND SOUTH PARK...

* AFFECTED AREA...Fire Weather Zones 214, 216, 238, 239, 240, 
  241, 242, 243, 244, 245, 246, 247, 248, 249, 250 and 251.

* TIMING...For the first Red Flag Warning, until midnight MDT 
  tonight. For the second Red Flag Warning, from 11 AM to 7 PM 
  MDT Thursday.

* WINDS...Northwest 15 to 25 mph with gusts up to 40 mph, with
  gusts up to 50 mph across the Southern Front Range Foothills and
  South Park through early Thursday afternoon.

* RELATIVE HUMIDITY...As low as 10 percent Thursday.

* IMPACTS...Conditions will be favorable for rapid fire spread. 
  Avoid outdoor burning and any activity that may produce a 
  spark and start a wildfire.

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.

&&

$$

COZ215-230600-
/O.CON.KBOU.FW.W.0037.000000T0000Z-260423T0600Z/
Larimer and Boulder Counties Between 6000 and 9000 Feet-
844 PM MDT Wed Apr 22 2026

...RED FLAG WARNING REMAINS IN EFFECT UNTIL MIDNIGHT MDT TONIGHT
FOR WIND AND LOW RELATIVE HUMIDITY FOR THE NORTHERN FRONT RANGE
FOOTHILLS...

* AFFECTED AREA...Fire Weather Zone 215.

* TIMING...Until midnight MDT tonight.

* WINDS...West 15 to 25 mph with gusts up to 35 mph.

* RELATIVE HUMIDITY...As low as 11 percent.

* IMPACTS...Conditions will be favorable for rapid fire spread. 
  Avoid outdoor burning and any activity that may produce a 
  spark and start a wildfire.

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.

&&

$$

385 
WWUS85 KBOU 230551
RFWBOU

URGENT - FIRE WEATHER MESSAGE
National Weather Service Denver/Boulder CO
1151 PM MDT Wed Apr 22 2026

COZ214-247-231930-
/O.EXP.KBOU.FW.W.0037.000000T0000Z-260423T0600Z/
/O.NEW.KBOU.FW.A.0029.260424T1700Z-260425T0300Z/
/O.CON.KBOU.FW.W.0038.260423T1700Z-260424T0100Z/
Central and Southeast Park County-
Southeast Elbert County Below 6000 Feet/South Lincoln County-
1151 PM MDT Wed Apr 22 2026

...RED FLAG WARNING REMAINS IN EFFECT FROM 11 AM TO 7 PM MDT
THURSDAY FOR WIND AND LOW RELATIVE HUMIDITY FOR SOUTH PARK AND
SOUTHERN LINCOLN COUNTY... 
...FIRE WEATHER WATCH IN EFFECT FROM FRIDAY MORNING THROUGH 
FRIDAY EVENING FOR WIND AND LOW RELATIVE HUMIDITY FOR SOUTH PARK AND
SOUTHERN LINCOLN COUNTY... 
...RED FLAG WARNING WILL EXPIRE AT MIDNIGHT MDT TONIGHT FOR WIND 
AND LOW RELATIVE HUMIDITY FOR SOUTH PARK AND SOUTHERN LINCOLN 
COUNTY...

The National Weather Service in Denver has issued a Fire Weather
Watch for wind and low relative humidity, which is in effect from
Friday morning through Friday evening.

* AFFECTED AREA...Fire Weather Zones 214 and 247.

* TIMING...For the Red Flag Warning, from 11 AM to 7 PM MDT 
  Thursday. For the Fire Weather Watch, from Friday morning 
  through Friday evening.

* WINDS...For the Red Flag Warning, northwest 15 to 25 mph with
  gusts up to 40 mph. For the Fire Weather Watch, west 10 to 20 
  mph with gusts up to 35 mph.

* RELATIVE HUMIDITY...As low as 10 percent on Thursday. As low as
  7 percent on Friday.

* IMPACTS...Conditions will be favorable for rapid fire spread. 
  Avoid outdoor burning and any activity that may produce a 
  spark and start a wildfire.

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.

&&

$$

COZ216-238>246-248>251-231930-
/O.EXP.KBOU.FW.W.0037.000000T0000Z-260423T0600Z/
/O.CON.KBOU.FW.W.0038.260423T1700Z-260424T0100Z/
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-Central and South Weld County-Morgan County-
Central and East Adams and Arapahoe Counties-
North and Northeast Elbert County Below 6000 Feet/North Lincoln
County-Logan County-Washington County-Sedgwick County-
Phillips County-
1151 PM MDT Wed Apr 22 2026

...RED FLAG WARNING REMAINS IN EFFECT FROM 11 AM TO 7 PM MDT
THURSDAY FOR WIND AND LOW RELATIVE HUMIDITY FOR THE SOUTHERN
FRONT RANGE FOOTHILLS, URBAN CORRIDOR, AND PLAINS... 
...RED FLAG WARNING WILL EXPIRE AT MIDNIGHT MDT TONIGHT FOR WIND 
AND LOW RELATIVE HUMIDITY FOR THE SOUTHERN FRONT RANGE FOOTHILLS, 
URBAN CORRIDOR, AND PLAINS...

* AFFECTED AREA...Fire Weather Zones 216, 238, 239, 240, 241, 
  242, 243, 244, 245, 246, 248, 249, 250 and 251.

* TIMING...From 11 AM to 7 PM MDT Thursday.

* WINDS...Northwest 15 to 25 mph with gusts up to 40 mph, with
  gusts up to 50 mph across the southern Front Range Foothills 
  and South Park through early Thursday afternoon..

* RELATIVE HUMIDITY...As low as 12 percent.

* IMPACTS...Conditions will be favorable for rapid fire spread. 
  Avoid outdoor burning and any activity that may produce a 
  spark and start a wildfire.

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.

&&

$$

COZ215-230700-
/O.EXP.KBOU.FW.W.0037.000000T0000Z-260423T0600Z/
Larimer and Boulder Counties Between 6000 and 9000 Feet-
1151 PM MDT Wed Apr 22 2026

...RED FLAG WARNING WILL EXPIRE AT MIDNIGHT MDT TONIGHT FOR WIND
AND LOW RELATIVE HUMIDITY FOR THE NORTHERN FRONT RANGE
FOOTHILLS...

While gusty winds continue, relative humidity has improved
significantly across the northern foothills.

$$

Area Forecast Discussion
National Weather Service Denver/Boulder CO
534 PM MDT Mon Apr 20 2026

.KEY MESSAGES...

- Dry and unseasonably warm weather continues through Wednesday.
  Highs will be nearly 20 degrees above normal Tuesday and
  Wednesday.

- Critical fire weather conditions likely on Wednesday due to
  increasing winds and very low humidity, with elevated to
  critical conditions continuing on Thursday.

- Pattern change to cooler and unsettled weather Friday through the
  upcoming weekend.

&&

.SHORT TERM /Through Wednesday/...
Issued at 152 PM MDT Mon Apr 20 2026

Upper level ridging will be in place across the region for the first
half of this week. For the plains, expect high temperatures in the
upper 70s and 80s today, tomorrow, and Wednesday with the mountain
valleys reaching the 60s. On Tuesday night into Wednesday morning, a
trough will move across the western US bringing southwest
(downslope) flow to our area.

Wednesday will bring elevated to critical fire weather conditions,
especially for the southern and eastern portions of our CWA. A mid-
level jet will move through the area with the main axis generally
located over the four corners region and SW CO on Wednesday
afternoon. Models still differ on the exact placement and strength
of this jet at this time affecting wind speed and gust forecasts.
A lee surface trough is also expected to develop bringing
tightening surface pressure gradients and enhancing the winds.
Relative humidity will be in the upper single digits to teens
across the Southern Foothills and all of the NE Colorado plains
for Wednesday afternoon into the evening. Some models even have RH
in the mid single digits on Wednesday afternoon across the Urban
Corridor and plains. These conditions have warranted us to issue
a Fire Weather Watch for Wednesday morning through Wednesday
evening. Gusts are expected to be around 30 to 40 mph with some
gusts as high as 45 mph expected, especially across Lincoln,
Elbert, and Washington counties. See the fire weather discussion
for more information.

&&

.LONG TERM /Wednesday night through Monday/...
Issued at 152 PM MDT Mon Apr 20 2026

A longwave upper level trough sets up over the western half of
Canada and extends into the Pacific Northwest and Northern
Rockies. Colorado will be under the base of the trough most of the
time through the weekend. Shortwave troughs pass through the
longwave trough, the first one will move across Colorado sometime
Wednesday night or Thursday. Gusty southwest winds ahead of this
system will decrease Wednesday evening as the airmass decouples.
Winds turn west and increase as the shortwave trough and
associated cold front sweep east across Colorado. This could
happen as early as Wednesday evening, according to the GFS or
Thursday morning according to the ECMWF. Either way, cooler
temperatures and gusty west winds are expected by Thursday
afternoon. This system could also bring rain and snow showers to
the high country. 

The forecast for Friday through Monday looks cool and unsettled
as Colorado generally remains at the bottom of the trough. The
timing of the rain/snow will depend on when the shortwave troughs 
pass over Colorado. Temperatures will fall below normal Friday
with highs in the upper 50s to lower 60s over northeast Colorado.
The cooling trend continues through the weekend. Sunday is
expected to be the coolest day as a shortwave trough from the
Pacific travels across Colorado. This storm system is expected to
have more moisture than the others. Both the GFS and ECMWF models
show this, so there is a little more confidence Sunday will be
cooler and possibly wet. 

&&

.AVIATION /00Z TAFS through 00Z Wednesday/...
Issued at 533 PM MDT Mon Apr 20 2026

VFR will persist through the period. Winds will follow fairly
normal diurnal patterns at KDEN and KAPA turning from ENE-SE-SSW
through 06Z tonight, and then holding S-SW through about 15Z.
Then expect a period of VRB winds 15Z-18Z Tuesday before an E-SE
component develops 18Z-20Z, and slowly increases to ~12kts on
average after 22Z. The main differences for KBJC will be that
winds start this period northerly, before a return to SW flow by
03Z-05Z tonight.

&&

.FIRE WEATHER...
Issued at 158 PM MDT Mon Apr 20 2026

Hot and dry conditions are expected for the first half of the week.
A trough moving over the Western US will bring gusty southwest to
west winds (30 to 45 mph) on Wednesday persisting well into the
evening hours. Single digit RH values are expected. This has led us
to issue a Fire Weather Watch for Wednesday morning through
Wednesday evening due to elevated to critical fire weather
conditions. The highest danger will be in the southeast portions of
the CWA, where winds will be the strongest.

Elevated to critical fire weather conditions will likely persist
into Thursday, but RH will be slightly higher- mainly in the low to
mid teens across the plains. Wind gusts around 30 to 35 mph are
expected on Thursday. Highlights could be needed for Thursday as
confidence increases, especially given the timing of the cold front.

The cooling trend continues Friday and into the weekend as
additional systems reinforce the cooler air and possibly bring
rain/snow showers. 

&&

.BOU WATCHES/WARNINGS/ADVISORIES...
Fire Weather Watch from Wednesday morning through Wednesday
evening for COZ214-216-238>251.

&&

SHORT TERM...MV
LONG TERM...12
AVIATION...20
FIRE WEATHER...12/MV