Red Flag Warning 40, NWS Cheyenne, WY

211 
WWUS85 KCYS 081251
RFWCYS

URGENT - FIRE WEATHER MESSAGE
National Weather Service Cheyenne WY
651 AM MDT Tue Sep 8 2026

...RED FLAG WARNING GOES INTO AFFECT AT NOON...

WYZ423-428-090000-
/O.EXA.KCYS.FW.W.0040.260908T1800Z-260909T0200Z/
Southwest Carbon County-Southern Laramie Valley-
651 AM MDT Tue Sep 8 2026

...RED FLAG WARNING IN EFFECT FROM NOON TODAY TO 8 PM MDT THIS
EVENING FOR LOW RH AND GUSTY WINDS FOR FIRE WEATHER ZONES 423 AND
428...

The National Weather Service in Cheyenne has issued a Red Flag
Warning, which is in effect from noon today to 8 PM MDT this
evening. 

* AFFECTED AREA...Fire weather zone 417.Fire weather zone 
  418.Fire weather zone 419.Fire weather zone 420.Fire weather 
  zone 421.Fire weather zone 422.Fire weather zone 427. 

* WIND... WESTERLY WINDS GUSTING TO 35 MPH

* HUMIDITY...BETWEEN 10 AND 15 PERCENT

* IMPACTS...any fires that develop will likely spread rapidly. 
  Outdoor burning is not recommended.

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.

&&

$$

WYZ417>422-427-090000-
/O.CON.KCYS.FW.W.0040.260908T1800Z-260909T0200Z/
Niobrara/Lower Elevations of Converse/Thunder Basin National
Grassland-
Middle North Platte River Basin/Niobrara and Converse High Plains-
North Laramie Range and Adjacent High Plains-
North Laramie Valley/Shirley Basin-
Ferris/Seminoe/Shirley Mountains-Central and West Carbon-
North Snowy Range Foothills-
651 AM MDT Tue Sep 8 2026

...RED FLAG WARNING REMAINS IN EFFECT FROM NOON TODAY TO 8 PM MDT
THIS EVENING FOR LOW RH AND GUSTY WINDS FOR FIRE WEATHER ZONES 
417, 418, 419, 420, 421, 422, AND 427...

* AFFECTED AREA...Fire weather zone 417.Fire weather zone 
  418.Fire weather zone 419.Fire weather zone 420.Fire weather 
  zone 421.Fire weather zone 422.Fire weather zone 427. 

* WIND... WESTERLY WINDS GUSTING TO 35 MPH

* HUMIDITY...BETWEEN 10 AND 15 PERCENT

* IMPACTS...any fires that develop will likely spread rapidly. 
  Outdoor burning is not recommended.

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.

&&

$$

839 
WWUS85 KCYS 081803
RFWCYS

URGENT - FIRE WEATHER MESSAGE
National Weather Service Cheyenne WY
1203 PM MDT Tue Sep 8 2026


WYZ417>423-427-428-090200-
/O.CON.KCYS.FW.W.0040.000000T0000Z-260909T0200Z/
Niobrara/Lower Elevations of Converse/Thunder Basin National
Grassland-
Middle North Platte River Basin/Niobrara and Converse High Plains-
North Laramie Range and Adjacent High Plains-
North Laramie Valley/Shirley Basin-
Ferris/Seminoe/Shirley Mountains-Central and West Carbon-
Southwest Carbon County-North Snowy Range Foothills-
Southern Laramie Valley-
1203 PM MDT Tue Sep 8 2026

...RED FLAG WARNING REMAINS IN EFFECT UNTIL 8 PM MDT THIS EVENING
FOR LOW RH AND GUSTY WINDS FOR FIRE WEATHER ZONES 417, 418, 419,
420, 421, 422, AND 427...

* AFFECTED AREA...Fire weather zones 417, 418, 419, 420, 421, 422,
  and 427. 

* WIND... WESTERLY WINDS GUSTING TO 35 MPH

* HUMIDITY...BETWEEN 10 AND 15 PERCENT

* IMPACTS...Any fires that develop will likely spread rapidly. 
  Outdoor burning is not recommended.

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.

&&

$$

830 
WWUS85 KCYS 090134
RFWCYS

URGENT - FIRE WEATHER MESSAGE
National Weather Service Cheyenne WY
734 PM MDT Tue Sep 8 2026

WYZ417>423-427-428-090245-
/O.EXP.KCYS.FW.W.0040.000000T0000Z-260909T0200Z/
Niobrara/Lower Elevations of Converse/Thunder Basin National
Grassland-
Middle North Platte River Basin/Niobrara and Converse High Plains-
North Laramie Range and Adjacent High Plains-
North Laramie Valley/Shirley Basin-
Ferris/Seminoe/Shirley Mountains-Central and West Carbon-
Southwest Carbon County-North Snowy Range Foothills-
Southern Laramie Valley-
734 PM MDT Tue Sep 8 2026

...RED FLAG WARNING WILL EXPIRE AT 8 PM MDT THIS EVENING FOR LOW
RH AND GUSTY WINDS FOR FIRE WEATHER ZONES 417, 418, 419, 420,
421, 422, AND 427...

...RED FLAG WARNING IN EFFECT FROM 11 AM WEDNESDAY MORNING UNTIL 8
PM THURSDAY EVENING FOR LOW HUMIDITIES AND GUSTY WINDS...

Gusty winds are starting to diminish this evening with relative 
humidities recovering above 20 percent for most of the area.
Therefore, will allow the Red Flag Warning to expire on time.

Another Red Flag Warning will be issued shortly, beginning at 11
AM Wednesday morning and continuing through Thursday evening. 

$$

Area Forecast Discussion
National Weather Service Cheyenne WY
529 AM MDT Tue Sep 8 2026

.KEY MESSAGES...

- Chances for light and brief showers with temporary strong wind
  gusts possible this evening.

- A temporary drying trend begins Tuesday and possibly
  continuing through the end of the week.

&&

.SHORT TERM /THROUGH WEDNESDAY NIGHT/...
Issued at 254 AM MDT Tue Sep 8 2026

Some weak showers persist following a surface cold front that is
expected to stall along the WY/CO border. The upper level low is
directly north of our forecast area along the Canadian Border ever
so slowly pushing east. A 700mb cold front will push through
tomorrow dropping 700mb temperatures from 12/14C down to around 6/7c
around peak heating to the evening time. Due to the kind of late
arrival surface temperatures will only be 4 degrees cooler from the
previous day. This cold front may create some light showers in the
southern counties where low level moisture gets trapped underneath
our expanding ridge. Hi-res models depict a swath of 200-500 joules
of CAPE in some areas but depending how fast the winds switch from
southwest to west as the upper level low pulls further away from us
some clouds may form and may not produce any precipitation. Instead
we will get gusty outflows and microburst in the evening into the
overnight hours. Hi-res guidance clears the showers out by 06z or
midnight. Wednesday, we will continue to be predominantly in our
westerly downsloping flow. The downsloping flow will keep the colder
airmass above us from dropping the temperature below 70 degrees. The
daily high temperature is expected to be mostly in the 70's with the
Nebraska Panhandle in the low 80's.  Overnight temperatures will be
a bit cooler with temperatures in the 40's and 50's.

&&

.LONG TERM /THURSDAY THROUGH MONDAY/...
Issued at 254 AM MDT Tue Sep 8 2026

The ridge continues to elongate through the middle of the work
week, placing our area in primarily zonal flow aloft and
therefore mostly dry conditions. A warming trend is expected on
Thursday and Friday as a secondary ridge begins to build across
the Desert Southwest. Will have to monitor fire weather
conditions on both of these days as ensemble guidance is hinting
at gusty westerly winds of 25-35 knots combined with daytime RH
values dipping to 15- 20%.

Heading into the weekend, we start to bring back the fetch of
monsoonal moisture ahead of a shortwave trough digging across the
Pacific Northwest, placing Southeastern Wyoming and Western Nebraska
in WSW flow aloft. With the lack of signal for any substantial
forcing from long-range ensemble guidance, no widespread (and
beneficial) precipitation is expected. However can expect a slight
cooling trend with this next push of moisture and the usual diurnal
pattern of scattered afternoon and evening showers and
thunderstorms.

&&

.AVIATION /12Z TAFS THROUGH 12Z WEDNESDAY/...
Issued at 530 AM MDT Tue Sep 8 2026

Showers are slowly dissipating between KSNY and KAIA this
morning with the ceiling between 095 and 15,000ft expect clouds
to clear out through the morning. In the afternoon a surface low
will move across the Panhandle making the winds light and
variable. After 23z light showers will form over KCYS and move
East-Northeast possibly moving over KBFF, KAIA, and KSNY. Its
unsure if these showers will produce virga or raindrops so VCSH
was used to describe this uncertainty. The skies will clear out
through the night and into tomorrow morning. Wind gusts will be
erratic under these showers. For KRWL and KLAR only wind gusts
will reach up to 25-30kts by the afternoon and last until around
01z.

&&

.CYS WATCHES/WARNINGS/ADVISORIES...
WY...None.
NE...None.

&&

SHORT TERM...MM
LONG TERM...NB
AVIATION...MM