Red Flag Warning 45, NWS Denver/Boulder, CO

605 
WWUS85 KBOU 200325
RFWBOU

URGENT - FIRE WEATHER MESSAGE
National Weather Service Denver/Boulder CO
925 PM MDT Fri Jun 19 2026


COZ211>214-217-218-201530-
/O.CON.KBOU.FW.W.0045.260620T1700Z-260621T0300Z/
Jackson County Below 9000 Feet-
South and Southeast Grand/West Central and Southwest Boulder/
Gilpin/Clear Creek/Summit/North and West Park Counties Above
9000 Feet-Grand and Summit Counties Below 9000 Feet-
Central and Southeast Park County-
West Jackson and West Grand Counties Above 9000 Feet-
South and East Jackson/Larimer/North and Northeast Grand/
Northwest Boulder Counties Above 9000 Feet-
925 PM MDT Fri Jun 19 2026

...RED FLAG WARNING REMAINS IN EFFECT FROM 11 AM TO 9 PM MDT
SATURDAY FOR WIND AND LOW RELATIVE HUMIDITY FOR THE MOUNTAINS AND
MOUNTAIN VALLEYS...

* AFFECTED AREA...Fire Weather Zones 211, 212, 213, 214, 217 and 
  218.

* TIMING...From 11 AM to 9 PM MDT Saturday.

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

&&

$$

346 
WWUS85 KBOU 200640
RFWBOU

URGENT - FIRE WEATHER MESSAGE
National Weather Service Denver/Boulder CO
1240 AM MDT Sat Jun 20 2026


COZ211>214-217-218-210300-
/O.CON.KBOU.FW.W.0045.260620T1700Z-260621T0300Z/
Jackson County Below 9000 Feet-
South and Southeast Grand/West Central and Southwest Boulder/
Gilpin/Clear Creek/Summit/North and West Park Counties Above
9000 Feet-Grand and Summit Counties Below 9000 Feet-
Central and Southeast Park County-
West Jackson and West Grand Counties Above 9000 Feet-
South and East Jackson/Larimer/North and Northeast Grand/
Northwest Boulder Counties Above 9000 Feet-
1240 AM MDT Sat Jun 20 2026

...RED FLAG WARNING REMAINS IN EFFECT FROM 11 AM THIS MORNING TO
9 PM MDT THIS EVENING FOR WIND AND LOW RELATIVE HUMIDITY FOR THE
MOUNTAINS AND MOUNTAIN VALLEYS...

* AFFECTED AREA...Fire Weather Zones 211, 212, 213, 214, 217 and 
  218.

* TIMING...From 11 AM this morning to 9 PM MDT this evening.

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

&&

$$

199 
WWUS85 KBOU 201733
RFWBOU

URGENT - FIRE WEATHER MESSAGE
National Weather Service Denver/Boulder CO
1133 AM MDT Sat Jun 20 2026

COZ211>214-217-218-210145-
/O.CON.KBOU.FW.W.0045.000000T0000Z-260621T0300Z/
Jackson County Below 9000 Feet-
South and Southeast Grand/West Central and Southwest Boulder/
Gilpin/Clear Creek/Summit/North and West Park Counties Above
9000 Feet-Grand and Summit Counties Below 9000 Feet-
Central and Southeast Park County-
West Jackson and West Grand Counties Above 9000 Feet-
South and East Jackson/Larimer/North and Northeast Grand/
Northwest Boulder Counties Above 9000 Feet-
1133 AM MDT Sat Jun 20 2026

...RED FLAG WARNING REMAINS IN EFFECT UNTIL 9 PM MDT THIS EVENING
FOR WIND AND LOW RELATIVE HUMIDITY FOR THE MOUNTAINS AND MOUNTAIN
VALLEYS...

* AFFECTED AREA...Fire Weather Zones 211, 212, 213, 214, 217 and 
  218.

* TIMING...Until 9 PM MDT this evening.

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

&&

$$

278 
WWUS85 KBOU 210256
RFWBOU

URGENT - FIRE WEATHER MESSAGE
National Weather Service Denver/Boulder CO
856 PM MDT Sat Jun 20 2026


COZ211>214-217-218-210400-
/O.EXP.KBOU.FW.W.0045.000000T0000Z-260621T0300Z/
Jackson County Below 9000 Feet-
South and Southeast Grand/West Central and Southwest Boulder/
Gilpin/Clear Creek/Summit/North and West Park Counties Above
9000 Feet-Grand and Summit Counties Below 9000 Feet-
Central and Southeast Park County-
West Jackson and West Grand Counties Above 9000 Feet-
South and East Jackson/Larimer/North and Northeast Grand/
Northwest Boulder Counties Above 9000 Feet-
856 PM MDT Sat Jun 20 2026

...RED FLAG WARNING WILL EXPIRE AT 9 PM MDT THIS EVENING FOR WIND
AND LOW RELATIVE HUMIDITY FOR THE MOUNTAINS AND MOUNTAIN
VALLEYS...

Winds and relative humidities have improved for much of the warned
area, with improving conditions expected over the next hour. The
Red Flag Warning will be allowed to expire at 9PM, but localized
areas of critical fire weather conditions will be possible for the
next hour or two. 

$$

Area Forecast Discussion
National Weather Service Denver/Boulder CO
531 AM MDT Fri Jun 19 2026

.KEY MESSAGES...

- Isolated showers and thunderstorms possible near the southern
  foothills and Palmer Divide today. A few storms could become
  strong to severe in the late afternoon.

- Elevated fire weather conditions in the mountains and valleys
  today with critical conditions expected on Saturday.

- Strong to severe storms possible across the eastern plains on
  Saturday and Sunday.

- Scattered coverage of showers and storms on Sunday and Monday.

&&

.DISCUSSION /Through Thursday/...
Issued at 208 AM MDT Fri Jun 19 2026

Another relatively quiet day for most of the forecast area, as
the axis of the upper level ridge begins shifting east into
Colorado. Elevated fire weather conditions are possible again for
the mountains and high valleys, as relative humidity values
plummet to 8-15% in the afternoon. However, with weak flow aloft
due to the ridging, winds will be relatively light (<25 mph). For
the plains, low-level moisture will be advected into the region
throughout the morning and afternoon. With a passage of a boundary
in the afternoon, northerly winds will provide just enough upslope
flow to promote isolated showers and thunderstorms, mainly near
the southern foothills and Palmer Divide area. Modeled Skew-T
soundings show DCAPE values reaching up to 1200 J/kg, so gusty
outflow winds will be the primary threat. As these storms trek
east into Lincoln county area, elevated warm air advection and
thus better instability may allow some storms to become strong-
to-severe, with hail possible. SPC has introduced a Marginal (1/5)
risk for Lincoln county, which seems reasonable if storms can
overcome a capped environment.

Saturday is shaping up to be the most active day for the forecast
period, with critical fire weather conditions expected for the
mountains and high valleys, and severe thunderstorms possible for
the plains. For the mountains and valleys, upper level ridging
will flatten due to an incoming shortwave trough. Winds across the
high terrain will strengthen, with gusts up to 45 mph possible.
Critical fire weather conditions are expected in the afternoon, as
relative humidity values drop to 10%.

For the plains, a lee side cyclone will develop on Saturday ahead
of the incoming shortwave. South/southeast winds will advect low-
level moisture into the region, with hi-res guidance showing
dewpoint temperatures up to the low 60s across the eastern plains.
Model trends have shown a more westward extent of the dryline (as
expected) which would allow more coverage of showers and
thunderstorms in the afternoon. Supercells should develop off the
dryline and trek east through the afternoon and evening. Modeled
soundings across eastern Colorado show MLCAPE up to 2500-3000
J/kg, deep layer shear, and steep mid-level lapse rates, which are
all indicative of an environment favorable for very large hail.
There is also a low-end tornado threat later in the afternoon for
our northeastern plains, along the frontal boundary where LCLs
will be lower. SPC has our plains in a Slight risk (2/5) and has
introduced an Enhanced risk (3/5) just east of our forecast area.
Would not be surprised if that gets expanded westward in later
forecast packages given recent model trends. Lastly, localized
flooding is possible with the strongest storms, as guidance has
shown PWAT values up to 1.5".

With the arrival of another shortwave on Sunday, additional
showers and thunderstorms are expected across the plains, with a
few storms becoming strong/severe. Forecast soundings once again
show MLCAPE up to 2000-2500 J/kg, with deep layers shear and steep
mid-level lapse rates. Supercells will have the capability to
produce large hail and gusty outflow winds, given decent DCAPE
values. SPC has introduced a Slight risk for our far eastern
plains.

Next week will continue to be active, as guidance favors multiple
shortwaves passing through, allowing daily chances for showers and
thunderstorms mainly for the foothills and plains. For Monday,
there could be a few strong/severe storms across the plains.
However, instability and shear profiles do not look as favorable
as they do for the weekend. Ensemble guidance is in good agreement
of temperatures cooling down with these systems, with forecasted
highs in the low 80s. However, an upper level ridge is expected to
build over the southwestern U.S. by mid week, and thus warm air
advection will bring temperatures back up to the 90s by
Wednesday/Thursday.

&&

.AVIATION /12Z TAFS through 12Z Saturday/...
Issued at 521 AM MDT Fri Jun 19 2026

VFR conditions expected through the TAF period, although there is
a chance for MVFR and potentially IFR conditions overnight Friday
night into Saturday morning. Winds are currently transitioning to
a light (<10 kts) northwest ahead of an incoming boundary. By
16Z/17Z winds should strengthen to 12-15 kts and turn more
northeasterly before shifting more east by the afternoon. There is
some uncertainty with winds in the evening, as models try to
resolve a circulation that could make winds light and VRB at DEN
and APA. In addition, there could be outflow boundaries from
convection over the Palmer Divide that may make winds
south/southeasterly for a time.

Overnight tonight, easterly flow will advect low-level moisture
into the plains. Guidance is not in agreement of how far west low
clouds extend, but ceilings of 3000-4000 ft are possible by
Saturday morning, with the potential for fog to make it to DEN.
For now have kept any mention of fog out of the TAFs due to low
confidence but it may have to be included in next updates.

&&

.BOU WATCHES/WARNINGS/ADVISORIES...
Fire Weather Watch from Saturday afternoon through Saturday
evening for COZ211>214-217-218.

&&

DISCUSSION...MAI
AVIATION...MAI