Alert archive / Colorado / Red Flag Warnings in 2020

Red Flag Warning 24, NWS Denver/Boulder, CO

September 4, 202018 counties in Colorado

NWS Denver/Boulder, CO issued this red flag warning at Sep 4, 2020, 2:40 PM MDT for 18 counties in Colorado. It took effect at Sep 6, 2020, 12:00 AM MDT. It was in force for 44 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
Sep 4, 2020, 2:40 PM MDT (20:40 UTC)
In effect from
Sep 6, 2020, 12:00 AM MDT
Expired
Sep 7, 2020, 7:54 PM MDT
In force
44 hr
Issued by
NWS Denver/Boulder, CO

Counties Adams County, CO, Arapahoe County, CO, Boulder County, CO, Clear Creek County, CO, Elbert County, CO, Gilpin County, CO, Grand County, CO, Jackson County, CO, Larimer County, CO, Lincoln County, CO, Logan County, CO, Morgan County, CO, Park County, CO, Phillips County, CO, Sedgwick County, CO, Summit County, CO, Washington County, CO, Weld County, CO

The radar

The Denver radar (KFTG), 28 km from the middle of the area, began a volume at 20:39 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, 8.7 hours before the alert went out and 114 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 2020-09-04Temperature 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 km15 km-30°-20°-10°0°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Denver, CO at 12:00Z on 2020-09-04The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 9 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
2997 m above ground
0-6 km bulk shear
27 kt
0-1 km storm-relative helicity
9 m²/s²
0-3 km storm-relative helicity
28 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

091 
WWUS85 KBOU 042040
RFWBOU

URGENT - FIRE WEATHER MESSAGE
National Weather Service Denver/Boulder CO
240 PM MDT Fri Sep 4 2020

...EXTENDED PERIOD OF HIGH FIRE DANGER...

.Record or near record heat, very dry conditions, and increasing
winds will bring critical fire danger to much of the northern
mountains and high valleys of northern Colorado Sunday and Monday.
The high fire danger may spread to the northern foothills and
across the plains on Sunday as well.  

COZ211>213-217-218-051200-
/O.NEW.KBOU.FW.W.0024.200906T1800Z-200908T0200Z/
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-
West Jackson and West Grand Counties Above 9000 Feet-
South and East Jackson/Larimer/North and Northeast Grand/
Northwest Boulder Counties Above 9000 Feet-
240 PM MDT Fri Sep 4 2020

...RED FLAG WARNING IN EFFECT FROM NOON SUNDAY TO 8 PM MDT MONDAY
FOR WIND AND LOW RELATIVE HUMIDITY FOR THE MOUNTAINS AND HIGH
MOUNTAIN VALLEYS...

The National Weather Service in Denver has issued a Red Flag
Warning FOR WIND AND LOW RELATIVE HUMIDITY, which is in effect
from noon Sunday to 8 PM MDT Monday.

* Affected Area...Fire Weather Zones 211...212...213...217 and 
  218.

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

* Timing...Sunday noon through early evening Monday.

* Relative Humidity...As low as 9 percent during the afternoon
  hours, recovering only to around 30 percent Sunday night. 

* Impacts...Rapid growth of existing fires and new fire starts
  will be possible due to the gusty winds and very low humidity. 

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.

&&

$$

COZ215-238-242>251-051200-
/O.NEW.KBOU.FW.A.0016.200906T1600Z-200907T0200Z/
Larimer and Boulder Counties Between 6000 and 9000 Feet-
Larimer County Below 6000 Feet/Northwest Weld County-
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-
240 PM MDT Fri Sep 4 2020

...FIRE WEATHER WATCH IN EFFECT FROM SUNDAY MORNING THROUGH
SUNDAY EVENING FOR WIND AND LOW RELATIVE HUMIDITY FOR THE NORTHERN
FRONT RANGE FOOTHILLS AND MOST OF THE NORTHEAST PLAINS OF
COLORADO... 

The National Weather Service in Denver has issued a Fire Weather
Watch FOR WIND AND LOW RELATIVE HUMIDITY, which is in effect from
Sunday morning through Sunday evening.

* Affected Area...Fire Weather Zones 215...238...242...243... 
  244...245...246...247...248...249...250 and 251.

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

* Timing...Late Sunday morning until early Sunday evening. 

* Relative Humidity...As low as 8 percent.

* Impacts...Rapid fire growth will be possible. Avoid any activity
  outdoors that may produce a spark. 

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.

&&

$$
10 follow-up statements
047 
WWUS85 KBOU 050917
RFWBOU

URGENT - FIRE WEATHER MESSAGE
National Weather Service Denver/Boulder CO
317 AM MDT Sat Sep 5 2020

...EXTENDED PERIOD OF HIGH FIRE DANGER...

.Record or near record heat, very dry conditions, and increasing
winds will bring critical fire danger to much of the northern
mountains and high valleys of northern Colorado Sunday and
Monday. The high fire danger may spread to the northern foothills
and across the plains on Sunday as well.

COZ215-238-242>251-052100-
/O.UPG.KBOU.FW.A.0016.200906T1600Z-200907T0200Z/
/O.EXB.KBOU.FW.W.0024.200906T1800Z-200907T0200Z/
Larimer and Boulder Counties Between 6000 and 9000 Feet-
Larimer County Below 6000 Feet/Northwest Weld County-
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-
317 AM MDT Sat Sep 5 2020

...RED FLAG WARNING IN EFFECT FROM NOON TO 8 PM MDT SUNDAY FOR
WIND AND LOW RELATIVE HUMIDITY FOR THE NORTHERN FRONT RANGE FOOTHILLS 
AND MUCH OF THE NORTHEAST PLAINS, FIRE WEATHER ZONES 215, 238, 
AND 242 THROUGH 251...

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

* Affected Area...Fire Weather Zones 215...238...242...243... 
  244...245...246...247...248...249...250 and 251.

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

* Timing...Late Sunday morning until early Sunday evening.

* Relative Humidity...As low as 8 percent.

* Impacts...Rapid fire growth will be possible. Avoid any 
  activity outdoors that may produce a spark.

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.

&&

$$

COZ211>213-217-218-052100-
/O.CON.KBOU.FW.W.0024.200906T1800Z-200908T0200Z/
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-
West Jackson and West Grand Counties Above 9000 Feet-
South and East Jackson/Larimer/North and Northeast Grand/
Northwest Boulder Counties Above 9000 Feet-
317 AM MDT Sat Sep 5 2020

...RED FLAG WARNING REMAINS IN EFFECT FROM NOON SUNDAY TO 8 PM
MDT MONDAY FOR WIND AND LOW RELATIVE HUMIDITY FOR THE MOUNTAINS
AND HIGH MOUNTAIN VALLEYS...

* Affected Area...Fire Weather Zones 211...212...213...217 and 
  218.

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

* Timing...Sunday noon through early evening Monday.

* Relative Humidity...As low as 8 percent.

* Impacts...Rapid growth of existing fires and new fire starts 
  will be possible due to the gusty winds and very low humidity.

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.

&&

$$
954 
WWUS85 KBOU 051817
RFWBOU

URGENT - FIRE WEATHER MESSAGE
National Weather Service Denver/Boulder CO
1217 PM MDT Sat Sep 5 2020

...EXTENDED PERIOD OF HIGH FIRE DANGER...

.Record or near record heat, very dry conditions, and increasing
winds will bring critical fire danger to much of the northern
mountains and high valleys of northern Colorado Sunday and
Monday. The high fire danger may spread to the northern foothills
and across the plains on Sunday as well.

COZ215-238-242>251-060230-
/O.EXT.KBOU.FW.W.0024.200906T1600Z-200907T0200Z/
Larimer and Boulder Counties Between 6000 and 9000 Feet-
Larimer County Below 6000 Feet/Northwest Weld County-
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-
1217 PM MDT Sat Sep 5 2020

...RED FLAG WARNING NOW IN EFFECT FROM 10 AM TO 8 PM MDT SUNDAY
FOR WIND AND LOW RELATIVE HUMIDITY FOR THE NORTHERN FRONT RANGE
FOOTHILLS AND MUCH OF THE NORTHEAST PLAINS, FIRE WEATHER ZONES
215, 238, AND 242 THROUGH 251...

* Affected Area...Fire Weather Zones 215...238...242...243... 
  244...245...246...247...248...249...250 and 251.

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

* Timing...Late Sunday morning until early Sunday evening.

* Relative Humidity...As low as 8 percent.

* Impacts...Rapid fire growth will be possible. Avoid any 
  activity outdoors that may produce a spark.

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.

&&

$$

COZ211>213-217-218-060230-
/O.EXT.KBOU.FW.W.0024.200906T1600Z-200908T0200Z/
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-
West Jackson and West Grand Counties Above 9000 Feet-
South and East Jackson/Larimer/North and Northeast Grand/
Northwest Boulder Counties Above 9000 Feet-
1217 PM MDT Sat Sep 5 2020

...RED FLAG WARNING NOW IN EFFECT FROM 10 AM SUNDAY TO 8 PM MDT
MONDAY FOR WIND AND LOW RELATIVE HUMIDITY FOR THE MOUNTAINS AND
HIGH MOUNTAIN VALLEYS...

* Affected Area...Fire Weather Zones 211...212...213...217 and 
  218.

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

* Timing...Sunday noon through early evening Monday.

* Relative Humidity...As low as 8 percent.

* Impacts...Rapid growth of existing fires and new fire starts 
  will be possible due to the gusty winds and very low humidity.

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.

&&

$$
215 
WWUS85 KBOU 060226
RFWBOU

URGENT - FIRE WEATHER MESSAGE
National Weather Service Denver/Boulder CO
826 PM MDT Sat Sep 5 2020

...EXTENDED PERIOD OF HIGH FIRE DANGER...

.Record or near record heat, very dry conditions, and increasing
winds will bring critical fire danger to much of the northern
mountains and high valleys of northern Colorado Sunday and
Monday. Downslope winds will increase the fire danger in the
northern Front Range foothills later tonight, then spread across
the plains on Sunday. Humidities are expected to be a little
higher at lower elevations on Monday, but conditions could still
be near Red Flag criteria.

COZ215-061200-
/O.EXT.KBOU.FW.W.0024.200906T0600Z-200907T0200Z/
Larimer and Boulder Counties Between 6000 and 9000 Feet-
826 PM MDT Sat Sep 5 2020

...RED FLAG WARNING NOW IN EFFECT FROM MIDNIGHT TONIGHT TO 8 PM
MDT SUNDAY FOR WIND AND LOW RELATIVE HUMIDITY FOR THE NORTHERN
FRONT RANGE FOOTHILLS AND MUCH OF THE NORTHEAST PLAINS, FIRE
WEATHER ZONES 215, 238, AND 242 THROUGH 251...

* Affected Area...Fire Weather Zone 215.

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

* Timing...Midnight Saturday night until early Sunday evening.

* Relative Humidity...As low as 9 percent.

* Impacts...Rapid fire growth will be possible. Avoid any 
  activity outdoors that may produce a spark.

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.

&&

$$

COZ238-242>251-061200-
/O.CON.KBOU.FW.W.0024.200906T1600Z-200907T0200Z/
Larimer County Below 6000 Feet/Northwest Weld County-
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-
826 PM MDT Sat Sep 5 2020

...RED FLAG WARNING REMAINS IN EFFECT FROM 10 AM TO 8 PM MDT
SUNDAY FOR WIND AND LOW RELATIVE HUMIDITY FOR THE NORTHERN FRONT
RANGE FOOTHILLS AND MUCH OF THE NORTHEAST PLAINS, FIRE WEATHER
ZONES 215, 238, AND 242 THROUGH 251...

* Affected Area...Fire Weather Zones 238...242...243...244... 
  245...246...247...248...249...250 and 251.

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

* Timing...Late Sunday morning until early Sunday evening.

* Relative Humidity...As low as 8 percent.

* Impacts...Rapid fire growth will be possible. Avoid any 
  activity outdoors that may produce a spark.

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.

&&

$$

COZ211>213-217-218-061200-
/O.CON.KBOU.FW.W.0024.200906T1600Z-200908T0200Z/
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-
West Jackson and West Grand Counties Above 9000 Feet-
South and East Jackson/Larimer/North and Northeast Grand/
Northwest Boulder Counties Above 9000 Feet-
826 PM MDT Sat Sep 5 2020

...RED FLAG WARNING REMAINS IN EFFECT FROM 10 AM SUNDAY TO 8 PM
MDT MONDAY FOR WIND AND LOW RELATIVE HUMIDITY FOR THE MOUNTAINS
AND HIGH MOUNTAIN VALLEYS...

* Affected Area...Fire Weather Zones 211...212...213...217 and 
  218.

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

* Timing...Sunday noon through early evening Monday.

* Relative Humidity...As low as 9 percent.

* Impacts...Rapid growth of existing fires and new fire starts 
  will be possible due to the gusty winds and very low humidity.

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.

&&

$$

Gimmestad
608 
WWUS85 KBOU 061324
RFWBOU

URGENT - FIRE WEATHER MESSAGE
National Weather Service Denver/Boulder CO
724 AM MDT Sun Sep 6 2020

...EXTENDED PERIOD OF HIGH FIRE DANGER...

.Record or near record heat, very dry conditions, and increasing
winds will bring critical fire danger to much of the northern
mountains and high valleys of northern Colorado today and Monday.
Downslope winds will increase the fire danger in the northern 
Front Range foothills and plains today. Humidities are expected 
to be a little higher at lower elevations on Monday, but 
conditions could still be near Red Flag criteria.

COZ215-062130-
/O.CON.KBOU.FW.W.0024.000000T0000Z-200907T0200Z/
Larimer and Boulder Counties Between 6000 and 9000 Feet-
724 AM MDT Sun Sep 6 2020

...RED FLAG WARNING REMAINS IN EFFECT UNTIL 8 PM MDT THIS EVENING
FOR WIND AND LOW RELATIVE HUMIDITY FOR THE NORTHERN FRONT RANGE
FOOTHILLS AND MUCH OF THE NORTHEAST PLAINS, FIRE WEATHER ZONES
215, 238, AND 242 THROUGH 251...

* Affected Area...Fire Weather Zone 215.

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

* Timing...Today into early this evening.

* Relative Humidity...As low as 8 percent.

* Impacts...Rapid fire growth will be possible. Avoid any 
  activity outdoors that may produce a spark.

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.

&&

$$

COZ238-242>251-062130-
/O.CON.KBOU.FW.W.0024.200906T1600Z-200907T0200Z/
Larimer County Below 6000 Feet/Northwest Weld County-
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-
724 AM MDT Sun Sep 6 2020

...RED FLAG WARNING REMAINS IN EFFECT UNTIL 8 PM MDT THIS EVENING
FOR WIND AND LOW RELATIVE HUMIDITY FOR THE NORTHERN FRONT RANGE
FOOTHILLS AND MUCH OF THE NORTHEAST PLAINS, FIRE WEATHER ZONES
215, 238, AND 242 THROUGH 251...

* Affected Area...Fire Weather Zones 238...242...243...244... 
  245...246...247...248...249...250 and 251.

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

* Timing...Late this morning until early this evening.

* Relative Humidity...As low as 8 percent.

* Impacts...Rapid fire growth will be possible. Avoid any 
  activity outdoors that may produce a spark.

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.

&&

$$

COZ211>213-217-218-062130-
/O.CON.KBOU.FW.W.0024.200906T1600Z-200908T0200Z/
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-
West Jackson and West Grand Counties Above 9000 Feet-
South and East Jackson/Larimer/North and Northeast Grand/
Northwest Boulder Counties Above 9000 Feet-
724 AM MDT Sun Sep 6 2020

...RED FLAG WARNING REMAINS IN EFFECT UNTIL 8 PM MDT MONDAY FOR
WIND AND LOW RELATIVE HUMIDITY FOR THE MOUNTAINS AND HIGH
MOUNTAIN VALLEYS...

* Affected Area...Fire Weather Zones 211...212...213...217 and 
  218.

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

* Timing...Noon today through early this evening.

* Relative Humidity...As low as 10 percent.

* Impacts...Rapid growth of existing fires and new fire starts 
  will be possible due to the gusty winds and very low humidity.

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.

&&

$$
115 
WWUS85 KBOU 061752
RFWBOU

URGENT - FIRE WEATHER MESSAGE
National Weather Service Denver/Boulder CO
1152 AM MDT Sun Sep 6 2020

...EXTENDED PERIOD OF HIGH FIRE DANGER...

.Record or near record heat, very dry conditions, and increasing
winds will bring critical fire danger to much of the northern
mountains and high valleys of northern Colorado today and Monday.
Downslope winds will increase the fire danger in the northern
Front Range foothills and plains today. Humidities are expected
to be a little higher at lower elevations on Monday, but
conditions could still be near Red Flag criteria.

COZ215-070200-
/O.EXT.KBOU.FW.W.0024.000000T0000Z-200908T0200Z/
Larimer and Boulder Counties Between 6000 and 9000 Feet-
1152 AM MDT Sun Sep 6 2020

...RED FLAG WARNING NOW IN EFFECT UNTIL 8 PM MDT MONDAY FOR WIND
AND LOW RELATIVE HUMIDITY FOR THE NORTHERN FRONT RANGE FOOTHILLS
AND MUCH OF THE NORTHEAST PLAINS, FIRE WEATHER ZONES 215, 238,
AND 242 THROUGH 251...

* Affected Area...Fire Weather Zone 215.

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

* Timing...Today into early this evening.

* Relative Humidity...As low as 8 percent.

* Impacts...Rapid fire growth will be possible. Avoid any 
  activity outdoors that may produce a spark.

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.

&&

$$

COZ238-242>251-070200-
/O.CON.KBOU.FW.W.0024.000000T0000Z-200907T0200Z/
Larimer County Below 6000 Feet/Northwest Weld County-
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-
1152 AM MDT Sun Sep 6 2020

...RED FLAG WARNING REMAINS IN EFFECT UNTIL 8 PM MDT THIS EVENING
FOR WIND AND LOW RELATIVE HUMIDITY FOR THE NORTHERN FRONT RANGE
FOOTHILLS AND MUCH OF THE NORTHEAST PLAINS, FIRE WEATHER ZONES
215, 238, AND 242 THROUGH 251...

* Affected Area...Fire Weather Zones 238...242...243...244... 
  245...246...247...248...249...250 and 251.

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

* Timing...Late this morning until early this evening.

* Relative Humidity...As low as 8 percent.

* Impacts...Rapid fire growth will be possible. Avoid any 
  activity outdoors that may produce a spark.

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.

&&

$$

COZ211>213-217-218-070200-
/O.CON.KBOU.FW.W.0024.000000T0000Z-200908T0200Z/
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-
West Jackson and West Grand Counties Above 9000 Feet-
South and East Jackson/Larimer/North and Northeast Grand/
Northwest Boulder Counties Above 9000 Feet-
1152 AM MDT Sun Sep 6 2020

...RED FLAG WARNING REMAINS IN EFFECT UNTIL 8 PM MDT MONDAY FOR
WIND AND LOW RELATIVE HUMIDITY FOR THE MOUNTAINS AND HIGH
MOUNTAIN VALLEYS...

* Affected Area...Fire Weather Zones 211...212...213...217 and 
  218.

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

* Timing...Noon today through early this evening.

* Relative Humidity...As low as 10 percent.

* Impacts...Rapid growth of existing fires and new fire starts 
  will be possible due to the gusty winds and very low humidity.

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.

&&

$$
556 
WWUS85 KBOU 062132
RFWBOU

URGENT - FIRE WEATHER MESSAGE
National Weather Service Denver/Boulder CO
332 PM MDT Sun Sep 6 2020

...EXTENDED PERIOD OF EXTREME FIRE DANGER...

.Record or near record heat, very dry conditions, and increasing
winds will bring critical fire danger to much of the northern
mountains and high valleys of northern Colorado through Monday. 
Downslope winds will increase the fire danger in the northern 
Front Range foothills as well. Poor humidity recovery will occur
overnight, and Monday will see another day of dry and breezy
conditions with extreme fire danger.

Conditions on the plains will improve this evening as winds 
decrease. 

COZ238-242>251-070200-
/O.CON.KBOU.FW.W.0024.000000T0000Z-200907T0200Z/
Larimer County Below 6000 Feet/Northwest Weld County-
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-
332 PM MDT Sun Sep 6 2020

...RED FLAG WARNING REMAINS IN EFFECT UNTIL 8 PM MDT THIS EVENING
FOR WIND AND LOW RELATIVE HUMIDITY FOR MUCH OF THE NORTHEAST
PLAINS OF COLORADO...

* Affected Area...Fire Weather Zones 238...242...243...244... 
  245...246...247...248...249...250 and 251.

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

* Timing...Until 8 pm this evening.

* Relative Humidity...As low as 8 percent.

* Impacts...Rapid fire growth will be possible. Avoid any 
  activity outdoors that may produce a spark.

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.

&&

$$

COZ211>213-215-217-218-070600-
/O.CON.KBOU.FW.W.0024.000000T0000Z-200908T0200Z/
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-
Larimer and Boulder Counties Between 6000 and 9000 Feet-
West Jackson and West Grand Counties Above 9000 Feet-
South and East Jackson/Larimer/North and Northeast Grand/
Northwest Boulder Counties Above 9000 Feet-
332 PM MDT Sun Sep 6 2020

...RED FLAG WARNING REMAINS IN EFFECT UNTIL 8 PM MDT MONDAY FOR
WIND AND LOW RELATIVE HUMIDITY FOR THE MOUNTAINS...HIGH MOUNTAIN
VALLEYS...AND NORTHERN FRONT RANGE FOOTHILLS...

* Affected Area...Fire Weather Zones 211...212...213...215... 
  217 and 218.

* Winds...West 15 to 20 mph with gusts up to 35 mph.

* Timing...through tonight and Monday. 

* Relative Humidity...As low as 9 percent during the day, and
  humidity recovery only to around 30 percent tonight.

* Impacts...Rapid growth of existing fires and new fire starts 
  will be possible due to the gusty winds and very low humidity.

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.

&&

$$
035 
WWUS85 KBOU 070213
RFWBOU

URGENT - FIRE WEATHER MESSAGE
National Weather Service Denver/Boulder CO
813 PM MDT Sun Sep 6 2020

...ONE MORE DAY OF EXTREME FIRE DANGER IN THE MOUNTAINS...

.Temperatures will remain mild with low humidities over the
mountain ridges and foothills overnight, though winds will be
lighter. Monday will bring one more day of near record heat and 
very low humidities, and stronger winds. 

Conditions on the plains have improved as humidities increased 
and winds diminished this evening. However, it will be hot and
breezy on the plains again Monday afternoon. Humidities will only
be a little higher.

A cold front will bring strong north winds and quick cooling
Monday evening, with rain and snow developing by Tuesday morning.

COZ238-242>251-070315-
/O.EXP.KBOU.FW.W.0024.000000T0000Z-200907T0200Z/
Larimer County Below 6000 Feet/Northwest Weld County-
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-
813 PM MDT Sun Sep 6 2020

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

Conditions have moderated for the evening. On Monday, it will be
hot again and breezy by afternoon. Humidities will be a little
higher than they were today.

$$

COZ211>213-215-217-218-071200-
/O.CON.KBOU.FW.W.0024.000000T0000Z-200908T0200Z/
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-
Larimer and Boulder Counties Between 6000 and 9000 Feet-
West Jackson and West Grand Counties Above 9000 Feet-
South and East Jackson/Larimer/North and Northeast Grand/
Northwest Boulder Counties Above 9000 Feet-
813 PM MDT Sun Sep 6 2020

...RED FLAG WARNING REMAINS IN EFFECT UNTIL 8 PM MDT MONDAY FOR
WIND AND LOW RELATIVE HUMIDITY FOR THE MOUNTAINS...HIGH MOUNTAIN
VALLEYS...AND NORTHERN FRONT RANGE FOOTHILLS...

* Affected Area...Fire Weather Zones 211...212...213...215... 
  217 and 218.

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

* Timing...Lighter winds but poor humidity recovery tonight, then
  warm and windy on Monday.

* Relative Humidity...As low as 9 percent.

* Impacts...Rapid growth of existing fires and new fire starts 
  will be possible due to the gusty winds and very low humidity.

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.

&&

$$

Gimmestad
340 
WWUS85 KBOU 070958
RFWBOU

URGENT - FIRE WEATHER MESSAGE
National Weather Service Denver/Boulder CO
358 AM MDT Mon Sep 7 2020

...ONE MORE DAY OF EXTREME FIRE DANGER IN THE MOUNTAINS...

COZ211>213-215-217-218-072200-
/O.CON.KBOU.FW.W.0024.000000T0000Z-200908T0200Z/
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-
Larimer and Boulder Counties Between 6000 and 9000 Feet-
West Jackson and West Grand Counties Above 9000 Feet-
South and East Jackson/Larimer/North and Northeast Grand/
Northwest Boulder Counties Above 9000 Feet-
358 AM MDT Mon Sep 7 2020

...RED FLAG WARNING REMAINS IN EFFECT UNTIL 8 PM MDT THIS EVENING
FOR WIND AND LOW RELATIVE HUMIDITY FOR THE MOUNTAINS, HIGH 
MOUNTAIN VALLEYS, AND NORTHERN FRONT RANGE FOOTHILLS...

* Affected Area...Fire Weather Zones 211, 212, 213, 215, 217, and
  218.

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

* Timing...Through 8 PM MDT this evening.

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

* Impacts...Rapid growth of existing fires and new fire starts 
  will be possible due to the gusty winds and very low humidity.

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.

&&

$$
710 
WWUS85 KBOU 071929
RFWBOU

URGENT - FIRE WEATHER MESSAGE
National Weather Service Denver/Boulder CO
129 PM MDT Mon Sep 7 2020

...ONE MORE DAY OF EXTREME FIRE DANGER IN THE MOUNTAINS...

Westerly winds have increased over the mountains and ridges today
as warm temperatures also continue. Fire behavior on the Cameron
Peak Fire has been extreme today. Weather sensors near the fire
have been reporting wind gusts up to 53 mph. Winds above Berthoud
Pass have also gusted to a near 50 mph. Humidity levels have also
been very low as the late summer airmass remains over the state
today. The strong Canadian cold front that is expected to move
over the region this evening is going to bring strong winds out of
the north and then cooler temperatures by morning. Erratic fire
behavior will continue through this evening. Cooler temperatures
and higher humidity levels on Tuesday should begin easing the
extreme fire conditions. 

COZ211>213-215-217-218-080200-
/O.CON.KBOU.FW.W.0024.000000T0000Z-200908T0200Z/
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-
Larimer and Boulder Counties Between 6000 and 9000 Feet-
West Jackson and West Grand Counties Above 9000 Feet-
South and East Jackson/Larimer/North and Northeast Grand/
Northwest Boulder Counties Above 9000 Feet-
129 PM MDT Mon Sep 7 2020

...RED FLAG WARNING REMAINS IN EFFECT UNTIL 8 PM MDT THIS EVENING
FOR WIND AND LOW RELATIVE HUMIDITY FOR THE MOUNTAINS, HIGH
MOUNTAIN VALLEYS, AND NORTHERN FRONT RANGE FOOTHILLS...

* Affected Area...Fire Weather Zones 211...212...213...215... 
  217 and 218.

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

* Timing...Through 8 PM MDT this evening.

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

* Impacts...Rapid growth of existing fires and new fire starts 
  will be possible due to the gusty winds and very low humidity.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A Red Flag Warning means that critical fire weather conditions
are either occurring now....or will shortly. The combination of 
strong winds...low relative humidity...and warm temperatures will 
continue contributing to extreme fire behavior.

&&

$$
078 
WWUS85 KBOU 080154
RFWBOU

URGENT - FIRE WEATHER MESSAGE
National Weather Service Denver/Boulder CO
754 PM MDT Mon Sep 7 2020

COZ211>213-215-217-218-080300-
/O.CAN.KBOU.FW.W.0024.000000T0000Z-200908T0200Z/
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-
Larimer and Boulder Counties Between 6000 and 9000 Feet-
West Jackson and West Grand Counties Above 9000 Feet-
South and East Jackson/Larimer/North and Northeast Grand/
Northwest Boulder Counties Above 9000 Feet-
754 PM MDT Mon Sep 7 2020

...RED FLAG WARNING WILL EXPIRE AT 8 PM MDT FOR THE THE 
MOUNTAINS, HIGH MOUNTAIN VALLEYS, AND NORTHERN FRONT RANGE 
FOOTHILLS...

The National Weather Service in Denver has allowed the Red Flag 
Warning to expire this evening. A significant weather change is 
expected over all of north central and northeastern Colorado with
significantly colder air and a significant snowfall for the next 
couple of days. The fire danger will hopefully ease considerably.

$$

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 Sep 4, 11:11 AM MDT, 3 hours 29 minutes earlier.

Area forecast discussion, Sep 4, 11:11 AM MDT, 3 hours 29 minutes before
Area Forecast Discussion
National Weather Service Denver/Boulder CO
1111 AM MDT Fri Sep 4 2020

.UPDATE...
Issued at 1057 AM MDT Fri Sep 4 2020

Nary a cloud to be found over the CWA this morning. Latest model
data keeps the low level winds pretty weak all day for all the
CWA and there isn't much moisture either. Not much to alter this
update. May up the highs a degree or two.

&&

.SHORT TERM...(Today and tonight)
Issued at 201 AM MDT Fri Sep 4 2020

The upper level ridge will be centered over NV/UT today with a
weak and subsident northwesterly flow aloft. Temperatures will
climb back into the lower 90s across the urban corridor and
northeast plains. Weak pressure gradients at the surface coupled
with the weak flow aloft will allow for light winds across the
forecast area this afternoon. Clear and dry overnight.

.LONG TERM...(Saturday through Thursday)
Issued at 201 AM MDT Fri Sep 4 2020

...RECORD HEAT THIS WEEKEND TO POSSIBLE SNOW TUESDAY...

Upper level ridge centered over the Great Basin will retrograde
westward Sunday over California and Nevada. By Monday, what's left
of the ridge is just off the California coast. This ridge will
keep it hot and dry Saturday and Sunday. Highs across northeast
Colorado are expected to reach the mid 90s to lower 100s. A low
pressure trough across eastern Colorado and a short wave trough
passing to the north of Colorado will cause west to northwest
winds to increase Sunday. This downslope flow will produce very
dry conditions. It will likely offset any minor cooling associated
with the short wave trough.

A weak cold front drops south across the area Sunday night. Gusty
east winds behind it are expected for Monday. This will usher in
cooler air into northeast Colorado.

For Monday, models still showing a strong open trough over the
Northern Rockies. This trough then dives south and strengthens
into a closed low over somewhere near the Four Corner Tuesday. A
strong cold front associated with this system pushes south through
the state late Monday afternoon through Monday night.
Precipitation develops Monday evening and becomes widespread
overnight Monday night and Tuesday.

The 00Z GFS, GEM, and ECMWF are quite impressive with the amount
of cold that accompanies this storm system. If the current
solutions are right or close, it will be cold enough for snow to
fall along the Front Range Urban Corridor and nearby plains.
Accumulating snow on trees may cause considerable tree damage and
related impacts will be possible. This system is four days away
and models will likely change some. Confidence is becoming high
that snow will occur in the mountains and foothills Monday night
through Tuesday evening. A slight change in storm track or a
slightly weaker closed low may keep the lower elevations warm
enough for rain. Main message is cold and heavy snow is possible
Monday night through Tuesday night. Monitor the latest forecasts
and consider changing outdoor or travel plans if cold and snow
still look on track.

From Wednesday through Friday, the closed low gets cut off from the
main flow aloft. Not much agreement on where the low meanders
through the late weekend. Would expect temperatures to be well below
normal. As far as PoPs goes, will have the highest PoPs Wednesday
and then taper them down through the late week as the low will
likely be weakening.

&&

.AVIATION...(For the 18Z TAFS through 18Z Saturday afternoon)
Issued at 1057 AM MDT Fri Sep 4 2020

Models have east, then southeasterly winds at DIA with normal
drainage patterns by 04Z. No ceiling issues, in fact, no clouds,
for the most part.

&&

.FIRE WEATHER...
Issued at 201 AM MDT Fri Sep 4 2020

The fire danger today will be elevated with above normal
temperatures expected and minimum rh values in the teens. No dry
thunderstorms and light winds however will help to offset the
danger somewhat, therefore no highlights at this time.

It will be hot and dry Saturday and Sunday with record to near
record heat. Relative humidities are expected to fall to 5 to 12
percent during the afternoons. Winds become gusty Sunday afternoon
and will increase the fire danger. A cold front will usher gusty
easterly winds for Monday with higher relative humidities.

&&

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

UPDATE.........RJK
SHORT TERM.....Cooper
LONG TERM......Meier
AVIATION.......RJK
FIRE WEATHER...Meier
Hazardous weather outlook, Sep 4, 11:14 AM MDT, 3 hours 26 minutes before
Hazardous Weather Outlook
National Weather Service Denver/Boulder CO
1114 AM MDT Fri Sep 4 2020

COZ030>051-051715-
Jackson County Below 9000 Feet-
West Jackson and West Grand Counties Above 9000 Feet-
Grand and Summit Counties Below 9000 Feet-
South and East Jackson/Larimer/North and Northeast Grand/
Northwest Boulder Counties Above 9000 Feet-
South and Southeast Grand/West Central and Southwest Boulder/
Gilpin/Clear Creek/Summit/North and West Park Counties Above
9000 Feet-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-
Central and Southeast Park County-
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-
1114 AM MDT Fri Sep 4 2020

...Significant Change in the Weather Late Monday into Tuesday...

This hazardous weather outlook is for northeast and north central
Colorado.

.DAY ONE...Today and Tonight

Dry conditions are expected today with above normal high
temperatures. Winds will be pretty weak in most areas, but it
will be quite warm and dry. As a result, fire danger will be
elevated.

.DAYS TWO THROUGH SEVEN...Saturday through Thursday

Record or near record heat combined with very dry conditions will
result in elevated fire danger across the region through Sunday.
Winds will increase Sunday into Monday when critical fire danger
conditions may develop.

A significant change in the weather will occur late Monday into
Tuesday. Temperatures will plummet behind a strong cold front with
rain and snow forming. Snow levels will drop sharply and
accumulating snow is likely across the mountains and foothills.
We are still watching the track of this next storm system and how
much cold air arrives, but there is potential that the I-25
Corridor, including the Denver metro area, sees snow as well. If
snow does fall, tree damage and power outages will be possible.

.SPOTTER INFORMATION STATEMENT...

Spotter activation will not be be needed today and tonight.

The office that day

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

IssuedProductOfficeCountiesLasted
Sep 4, 2:40 PM MDTFire Weather WatchBOUAdams, Arapahoe, Boulder, Elbert, Larimer, Lincoln and 6 more13 hr

Nearby

Red Flag Warnings in Colorado, 2020Every red flag warning in 2020

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.