Alert archive / Colorado / Red Flag Warnings in 2026

Red Flag Warning 41, NWS Denver/Boulder, CO

June 5, 20265 counties in Colorado

NWS Denver/Boulder, CO issued this red flag warning at Jun 5, 2026, 1:00 PM MDT for 5 counties in Colorado. It took effect at Jun 6, 2026, 12:00 PM MDT. It was in force for 7 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
Jun 5, 2026, 1:00 PM MDT (19:00 UTC)
In effect from
Jun 6, 2026, 12:00 PM MDT
Expired
Jun 6, 2026, 7:00 PM MDT
In force
7 hr
Issued by
NWS Denver/Boulder, CO

Counties Adams County, CO, Arapahoe County, CO, Logan County, CO, Morgan County, CO, Weld County, CO

The radar

The Denver radar (KFTG), 67 km from the middle of the area, began a volume at 19:01 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 text

As transmitted.

766 
WWUS85 KBOU 051900
RFWBOU

URGENT - FIRE WEATHER MESSAGE
National Weather Service Denver/Boulder CO
100 PM MDT Fri Jun 5 2026


COZ242>245-248-060300-
/O.NEW.KBOU.FW.W.0041.260606T1800Z-260607T0100Z/
Northeast Weld County-Central and South Weld County-Morgan County-
Central and East Adams and Arapahoe Counties-Logan County-
100 PM MDT Fri Jun 5 2026

...RED FLAG WARNING IN EFFECT FROM NOON TO 7 PM MDT SATURDAY FOR
WIND AND LOW RELATIVE HUMIDITY FOR PORTIONS OF THE NORTHERN PLAINS
OF NORTHEAST COLORADO...

The National Weather Service in Denver has issued a Red Flag
Warning for wind and low relative humidity, which is in effect
from noon to 7 PM MDT Saturday.

* AFFECTED AREA...Fire Weather Zones 242, 243, 244, 245 and 248.

* TIMING...From noon to 7 PM MDT Saturday.

* WINDS...South 15 to 25 mph with gusts up to 40 mph.

* 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.

&&

$$
4 follow-up statements
649 
WWUS85 KBOU 060254
RFWBOU

URGENT - FIRE WEATHER MESSAGE
National Weather Service Denver/Boulder CO
854 PM MDT Fri Jun 5 2026

COZ242>245-248-061800-
/O.CON.KBOU.FW.W.0041.260606T1800Z-260607T0100Z/
Northeast Weld County-Central and South Weld County-Morgan County-
Central and East Adams and Arapahoe Counties-Logan County-
854 PM MDT Fri Jun 5 2026

...RED FLAG WARNING REMAINS IN EFFECT FROM NOON TO 7 PM MDT
SATURDAY FOR WIND AND LOW RELATIVE HUMIDITY FOR PORTIONS OF THE
NORTHERN PLAINS OF NORTHEAST COLORADO...

* AFFECTED AREA...Fire Weather Zones 242, 243, 244, 245 and 248.

* TIMING...From noon to 7 PM MDT Saturday.

* WINDS...South 15 to 25 mph with gusts up to 40 mph.

* RELATIVE HUMIDITY...As low as 13 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.

&&

$$
851 
WWUS85 KBOU 060925
RFWBOU

URGENT - FIRE WEATHER MESSAGE
National Weather Service Denver/Boulder CO
325 AM MDT Sat Jun 6 2026

COZ242>245-248-062200-
/O.CON.KBOU.FW.W.0041.260606T1800Z-260607T0100Z/
Northeast Weld County-Central and South Weld County-Morgan County-
Central and East Adams and Arapahoe Counties-Logan County-
325 AM MDT Sat Jun 6 2026

...RED FLAG WARNING REMAINS IN EFFECT FROM NOON TODAY TO 7 PM MDT
THIS EVENING FOR WIND AND LOW RELATIVE HUMIDITY FOR PORTIONS OF
THE NORTHEAST PLAINS OF COLORADO...

* AFFECTED AREA...Fire Weather Zones 242, 243, 244, 245 and 248.

* TIMING...From noon today to 7 PM MDT this evening.

* WINDS...Southeast 15 to 25 mph with gusts up to 30 mph.

* RELATIVE HUMIDITY...As low as 14 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.

&&

$$
249 
WWUS85 KBOU 061958
RFWBOU

URGENT - FIRE WEATHER MESSAGE
National Weather Service Denver/Boulder CO
158 PM MDT Sat Jun 6 2026


COZ242>245-248-070100-
/O.CON.KBOU.FW.W.0041.000000T0000Z-260607T0100Z/
Northeast Weld County-Central and South Weld County-Morgan County-
Central and East Adams and Arapahoe Counties-Logan County-
158 PM MDT Sat Jun 6 2026

...RED FLAG WARNING REMAINS IN EFFECT UNTIL 7 PM MDT THIS EVENING
FOR WIND AND LOW RELATIVE HUMIDITY FOR PORTIONS OF THE NORTHEAST
PLAINS OF COLORADO...

* AFFECTED AREA...Fire Weather Zones 242, 243, 244, 245 and 248.

* TIMING...Until 7 PM MDT this evening.

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

* RELATIVE HUMIDITY...As low as 14 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.

&&

$$
261 
WWUS85 KBOU 070104
RFWBOU

URGENT - FIRE WEATHER MESSAGE
National Weather Service Denver/Boulder CO
704 PM MDT Sat Jun 6 2026


COZ242>245-248-070215-
/O.EXP.KBOU.FW.W.0041.000000T0000Z-260607T0100Z/
Northeast Weld County-Central and South Weld County-Morgan County-
Central and East Adams and Arapahoe Counties-Logan County-
704 PM MDT Sat Jun 6 2026

...RED FLAG WARNING HAS EXPIRED FOR WIND AND LOW RELATIVE
HUMIDITY FOR PORTIONS OF THE NORTHEAST PLAINS OF COLORADO...

Relative humidities have improved and therefore the Red Flag
Warning has been allowed to expire.

$$

What forecasters said that day

The local office's own words before this red flag warning went out, as it sent them, from the Iowa Environmental Mesonet's archive of National Weather Service text.

NWS Denver/Boulder, CO wrote its last area forecast discussion before this red flag warning went out at Jun 5, 11:38 AM MDT, 1 hour 22 minutes earlier. Its key messages:

  • Warm today with a couple late day thunderstorms mainly south of Denver.
  • Hot weekend ahead with high temperatures soaring into the mid 90s across the I-25 Corridor and plains.
  • An early season heat wave likely Tuesday and Wednesday, possibly lasting into Thursday of next week. Highs near 100 degrees possible across portions of the plains.
Area forecast discussion, Jun 5, 11:38 AM MDT, 1 hour 22 minutes before
Area Forecast Discussion
National Weather Service Denver/Boulder CO
1138 AM MDT Fri Jun 5 2026

.KEY MESSAGES...

- Warm today with a couple late day thunderstorms mainly south of
  Denver.

- Hot weekend ahead with high temperatures soaring into the mid
  90s across the I-25 Corridor and plains.

- An early season heat wave likely Tuesday and Wednesday, possibly
  lasting into Thursday of next week. Highs near 100 degrees
  possible across portions of the plains.

&&

.DISCUSSION /Through Thursday/...
Issued at 241 AM MDT Fri Jun 5 2026

A weak cool front was pushing southward through southeast Wyoming
and the Nebraska Panhandle in these wee morning hours. Given
surface pressure rises are still organizing to the north, that
front is expected to push across all of the plains early this
morning. Only slight cooling can be expected today, however, as
the front will be rather shallow and offset by warm air aloft and
plenty of morning sunshine. We will see boundary layer moistening,
but also some low level stability given the slightly cooler
temperatures but still very warm airmass aloft. Thus, it will be
hard to reach convective temperatures over the plains and for the
most part they should stay capped off. However, the mountains and
elevated heat sources of the foothills and Palmer Divide will be
more prone to surface based convection given expectations of dry
adiabatic warming. Thus, we expect to see isolated high based
convection originate in the early to mid afternoon hours there.
Despite slight stability in the lower elevations, they will still
attempt to move eastward into the adjacent lower elevations with
perhaps even the southern portions of metro Denver seeing an
isolated late day or early evening storm, although gusty outflow
winds would be more likely than any rain.

Full on summer heat will arrive this weekend underneath upper
level ridging. We'll be essentially caught in between a weak
upper low drifting north through the Southern and Central Plains
and a deep mid latitude trough over the Pacific Northwest (PNW).
That supports development of southwest mid level flow and warm
advection. High temperatures will warm into the mid 90s over most
of the plains, with potentially a few spots getting into the upper
90s (depending on any influence from the trough to our east).
Denver's record for Saturday is 95F, and we should be very close
to that. Sunday's is a bit warmer (98F). While we should stay just
shy of Heat Advisory criteria, the record/near record heat early
in the season could put added stress on people who plan to be
outside for a majority of the day. Stay hydrated and avoid
strenuous outdoor activity during peak heating.

We will see isolated high based convection once again on Saturday
as limited low/mid level moisture remains under the ridge. Sunday
should trend mostly dry.

For Monday, we'll likely see a brief respite in the heat due to a
weak backdoor cold front - courtesy of the ejecting PNW trough.

We're confident (>80% chance) that we'll be right back to the
frying pan, however, for Tuesday and Wednesday. A strong ridge
aloft will develop over the Central Plains while a trough moves
into the western United States. That will lead to increasing
southwest flow across Colorado, further warm advection, and
downslope compressional warming. The combination of these factors
will lead to record/near record heat. Denver's record high of 95F
on Tuesday seems likely (60% chance) to be tied or broken, while
the record high of 99F on Wednesday has a chance (20-30%) of
being reached. Although recent greenup has been helpful, locally
critical fire weather conditions may start entering the picture
again if fuels dry sufficiently in the hot, dry, and windier
weather.

In contrast to yesterday's models, there is now some uncertainty
as to how long this heat wave will last, as both the latest EPS
and GEFS have cooled things off for Thursday. There seemed to be
better agreement with a quicker ejecting trough across the
Northern Rockies. Whether this is just a one-off or a meaningful
trend is yet to be seen, so something to watch in upcoming runs.

&&

.AVIATION /18Z TAFS through 18Z Saturday/...
Issued at 1135 AM MDT Fri Jun 5 2026

VFR conditions are expected throughout the TAF period. GOES-19
satellite imagery earlier this morning depicted some low clouds
across northeast Colorado as close to the TAF sites as northeast
Morgan County. These clouds have since scattered out. Some mid-
level clouds are moving over KDEN at the present time.

For this afternoon, virga showers are expected mainly for areas
near the Palmer Divide, potentially including KAPA where a TEMPO
is in place. KDEN could narrowly avoid these virga showers today,
but some gusty southerly winds to around 25 kts are still possible
from these showers located to the south. No impacts from virga
are expected today at KBJC.

Winds will turn to drainage tonight, but will still be around 10
kts. Winds should have a southerly to southwesterly component for
most of the day tomorrow. For tomorrow afternoon, have introduced
a PROB30 for virga showers. The latest HRRR model runs have
depicted scattered virga showers, DCAPE as high as 1500 J/kg, and
decent mid-level moisture. Other CAMs are also showing some
scattered virga showers near the TAF sites. These showers could
produce wind gusts as high as 30 kts and briefly lower the cloud
deck to about 10000 ft AGL.

&&

.BOU WATCHES/WARNINGS/ADVISORIES...
None.

&&

DISCUSSION...20
AVIATION...MV

The office that day

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

IssuedProductOfficeCountiesLasted
Jun 5, 4:33 PM MDTSpecial Weather StatementBOUElbert27 min
Jun 5, 5:03 PM MDTSpecial Weather StatementBOUElbert27 min
Jun 5, 5:10 PM MDTSevere Thunderstorm WarningBOUElbert35 min
Jun 5, 5:44 PM MDTSpecial Weather StatementBOUElbert31 min

Nearby

Red Flag Warnings in Colorado, 2026Every red flag warning in 2026

Sources

The product and its follow-ups from the Iowa Environmental Mesonet's archive of National Weather Service and Storm Prediction Center text; radar from the NEXRAD Level II archive.