Alert archive / South Dakota / Red Flag Warnings in 2021

Red Flag Warning 28, NWS Rapid City, SD

September 17, 2021Campbell County, Crook County, Weston County, Wyoming; 12 counties in South Dakota

NWS Rapid City, SD issued this red flag warning at Sep 17, 2021, 1:17 PM MDT for Campbell County, Crook County, Weston County, Wyoming; 12 counties in South Dakota. It took effect at Sep 18, 2021, 10:00 AM MDT. It was in force for 11 hr. 1 report came from inside the area while it was in force.

The area

The counties it named, with what was reported inside it.

The facts

Issued
Sep 17, 2021, 1:17 PM MDT (19:17 UTC)
In effect from
Sep 18, 2021, 10:00 AM MDT
Expired
Sep 18, 2021, 9:00 PM MDT
In force
11 hr
Issued by
NWS Rapid City, SD

Counties Bennett County, SD, Butte County, SD, Custer County, SD, Fall River County, SD, Haakon County, SD, Jackson County, SD, Lawrence County, SD, Meade County, SD, Oglala Lakota County, SD, Pennington County, SD, Perkins County, SD, Ziebach County, SD, Campbell County, WY, Crook County, WY, Weston County, WY

The radar

The Rapid City radar (KUDX), 19 km from the middle of the area, began a volume at 19:16 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.

What was reported inside it

TimeReportWhereRemark
Sep 18, 6:13 PM MDTNON-TSTM WND GST 585 Nnw Dwtn Gillette, WY

Local storm reports filed while the alert was in force, from inside its polygon or its counties.

The nearest sounding before it

Rapid City, SD (KUNR), launched 12:00Z, 7.3 hours before the alert went out and 18 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, Rapid City, SD at 12:00Z on 2021-09-17Temperature 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, Rapid City, SD at 12:00Z on 2021-09-17The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity -41 square meters per square second.1939587897Sfc1 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
1869 m above ground
0-6 km bulk shear
35 kt
0-1 km storm-relative helicity
-41 m²/s²
0-3 km storm-relative helicity
92 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

718 
WWUS83 KUNR 171917
RFWUNR

URGENT - FIRE WEATHER MESSAGE
National Weather Service Rapid City SD
117 PM MDT Fri Sep 17 2021

...RED FLAG WARNING REMAINS IN EFFECT UNTIL TO 8 PM MDT THIS 
EVENING FOR GUSTY WINDS AND LOW RELATIVE HUMIDITY FOR FIRE WEATHER
ZONES 314 AND 315 IN NORTHEASTERN WYOMING...

...RED FLAG WARNING IN EFFECT FROM SATURDAY MORNING THROUGH 
SATURDAY EVENING FOR GUSTY WINDS AND LOW RELATIVE HUMIDITY FOR
FIRE WEATHER ZONES 314 through 333 IN NORTHEASTERN WYOMING AND 
WESTERN SOUTH DAKOTA...

.Gusty southerly winds and minimum afternoon relative humidities 
in the upper teens to mid 20s will lead to elevated fire weather 
conditions. However, the relative humidity will drop around 15 
percent over the western half of fire weather zones 314 and 315 in
Campbell County Wyoming, leading to critical fire weather 
conditions in that area during the rest of this afternoon into 
early evening.

On Saturday, gusty west to southwest winds, as well as very dry 
air, will create critical fire weather conditions over
northeastern Wyoming and much of western South Dakota. Poor 
relative humidity recovery is also expected on Saturday night. 
Elevated fire weather conditions are possible on Sunday ahead of a
cold front for Sunday night. This cold front will be followed by 
gusty northwest winds as well as a chance of showers.

WYZ314-315-181200-
/O.UPG.KUNR.FW.A.0022.210918T1600Z-210919T0300Z/
/O.NEW.KUNR.FW.W.0028.210918T1600Z-210919T0300Z/
/O.CON.KUNR.FW.W.0027.000000T0000Z-210918T0200Z/
Northern Campbell-Southern Campbell-
117 PM MDT Fri Sep 17 2021

...RED FLAG WARNING REMAINS IN EFFECT UNTIL 8 PM MDT THIS EVENING
FOR GUSTY WINDS AND LOW RELATIVE HUMIDITY FOR FIRE WEATHER ZONES
314 AND 315...
...RED FLAG WARNING IN EFFECT FROM 10 AM TO 9 PM MDT SATURDAY FOR
GUSTY WINDS AND LOW RELATIVE HUMIDITY FOR FIRE WEATHER ZONES
314 AND 315...

The National Weather Service in Rapid City has issued a Red Flag
Warning for gusty winds and low relative humidity, which is in
effect from 10 AM to 9 PM MDT Saturday. The Fire Weather Watch is
no longer in effect.

* AFFECTED AREA...Fire Weather Zones 314 Northern Campbell and 
  315 Southern Campbell.

* WINDS...This afternoon, south 20 to 30 mph with gusts up to 40
  mph. On Saturday 15 to 25 mph with gusts up to 35 mph.

* RELATIVE HUMIDITY...This afternoon as low as 15 percent. On
  Saturday as low as 10 percent.

* IMPACTS...The combination of gusty winds and low relative 
  humidity would produce critical fire weather conditions.

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.

&&

$$

WYZ316>318-181200-
/O.UPG.KUNR.FW.A.0022.210918T1600Z-210919T0300Z/
/O.NEW.KUNR.FW.W.0028.210918T1600Z-210919T0300Z/
Crook County Plains-Weston County Plains-Wyoming Black Hills-
117 PM MDT Fri Sep 17 2021

...RED FLAG WARNING IN EFFECT FROM 10 AM TO 9 PM MDT SATURDAY FOR
GUSTY WINDS AND LOW RELATIVE HUMIDITY FOR FIRE WEATHER ZONES 316,
317, AND 318...

The National Weather Service in Rapid City has issued a Red Flag
Warning for gusty winds and low relative humidity, which is in
effect from 10 AM to 9 PM MDT Saturday. The Fire Weather Watch is
no longer in effect.

* AFFECTED AREA...Fire Weather Zones 316 Crook County Plains, 
  317 Weston County Plains and 318 Wyoming Black Hills.

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

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

* IMPACTS...The combination of gusty winds and low relative 
  humidity would produce critical fire weather conditions.

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.

&&

$$

SDZ323-327-181200-
/O.UPG.KUNR.FW.A.0022.210918T1600Z-210919T0300Z/
/O.NEW.KUNR.FW.W.0028.210918T1600Z-210919T0300Z/
Northern Foot Hills-Butte County Area-
117 PM MDT Fri Sep 17 2021

...RED FLAG WARNING IN EFFECT FROM 10 AM TO 9 PM MDT SATURDAY FOR
GUSTY WINDS AND LOW RELATIVE HUMIDITY FOR FIRE WEATHER ZONES
323 AND 327...

The National Weather Service in Rapid City has issued a Red Flag
Warning for gusty winds and low relative humidity, which is in
effect from 10 AM to 9 PM MDT Saturday. The Fire Weather Watch is
no longer in effect.

* AFFECTED AREA...Fire Weather Zones 323 Northern Foot Hills and 
  327 Butte County Area.

* WINDS...Southwest 10 to 20 mph with gusts up to 30 mph.

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

* IMPACTS...The combination of gusty winds and low relative 
  humidity would produce critical fire weather conditions.

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.

&&

$$

SDZ321-181200-
/O.UPG.KUNR.FW.A.0022.210918T1600Z-210919T0300Z/
/O.NEW.KUNR.FW.W.0028.210918T1600Z-210919T0300Z/
Southern Black Hills-
117 PM MDT Fri Sep 17 2021

...RED FLAG WARNING IN EFFECT FROM 10 AM TO 9 PM MDT SATURDAY FOR
GUSTY WINDS AND LOW RELATIVE HUMIDITY FOR FIRE WEATHER ZONE 321...

The National Weather Service in Rapid City has issued a Red Flag
Warning for gusty winds and low relative humidity, which is in
effect from 10 AM to 9 PM MDT Saturday. The Fire Weather Watch is
no longer in effect.

* AFFECTED AREA...Fire Weather Zone 321 Southern Black Hills.

* WINDS...Southwest 10 to 20 mph with gusts around 25 mph.

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

* IMPACTS...The combination of gusty winds and low relative 
  humidity would produce critical fire weather conditions.

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.

&&

$$

SDZ322-324>326-328>333-181200-
/O.UPG.KUNR.FW.A.0022.210918T1600Z-210919T0300Z/
/O.NEW.KUNR.FW.W.0028.210918T1600Z-210919T0300Z/
Fall River County Area-Eastern Foot Hills-Custer County Plains-
Pine Ridge Area-Perkins County-West Central Plains-Ziebach County-
Haakon County Area-Badlands Area-Bennett County Area-
117 PM MDT Fri Sep 17 2021

...RED FLAG WARNING IN EFFECT FROM 10 AM TO 9 PM MDT SATURDAY FOR
GUSTY WINDS AND LOW RELATIVE HUMIDITY FOR FIRE WEATHER ZONES 322,
324, 325, 326, 328, 329, 330, 331, 332, AND 333...

The National Weather Service in Rapid City has issued a Red Flag
Warning for gusty winds and low relative humidity, which is in
effect from 10 AM to 9 PM MDT Saturday. The Fire Weather Watch is
no longer in effect.

* AFFECTED AREA...Fire Weather Zones 322 Fall River County Area, 
  324 Eastern Foot Hills, 325 Custer County Plains, 326 Pine 
  Ridge Area, 328 Perkins County, 329 West Central Plains, 330 
  Ziebach County, 331 Haakon County Area, 332 Badlands Area and 
  333 Bennett County Area.

* WINDS...South 10 to 20 mph with gusts up to 30 mph.

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

* IMPACTS...The combination of gusty winds and low relative 
  humidity would produce critical fire weather conditions.

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.

&&

$$

SDZ319-320-181200-
/O.NEW.KUNR.FW.W.0028.210918T1600Z-210919T0300Z/
Northern Black Hills-Central Black Hills-
117 PM MDT Fri Sep 17 2021

...RED FLAG WARNING IN EFFECT FROM 10 AM TO 9 PM MDT SATURDAY FOR
GUSTY WINDS AND LOW RELATIVE HUMIDITY FOR FIRE WEATHER ZONES
319 AND 320...

The National Weather Service in Rapid City has issued a Red Flag
Warning for gusty winds and low relative humidity, which is in
effect from 10 AM to 9 PM MDT Saturday.

* AFFECTED AREA...Fire Weather Zones 319 Northern Black Hills 
  and 320 Central Black Hills.

* WINDS...Southwest 10 to 20 mph with gusts up to 30 mph.

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

* IMPACTS...The combination of gusty winds and low relative 
  humidity would produce critical fire weather conditions.

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.

&&

$$
5 follow-up statements
080 
WWUS83 KUNR 180150
RFWUNR

URGENT - FIRE WEATHER MESSAGE
National Weather Service Rapid City SD
750 PM MDT Fri Sep 17 2021


...RED FLAG WARNING IN EFFECT FROM SATURDAY MORNING THROUGH
SATURDAY EVENING FOR GUSTY WINDS AND LOW RELATIVE HUMIDITY FOR
FIRE WEATHER ZONES 314 through 333 IN NORTHEASTERN WYOMING AND
WESTERN SOUTH DAKOTA...

.On Saturday, gusty west to southwest winds, as well as very dry 
air, will create critical fire weather conditions over 
northeastern Wyoming and much of western South Dakota. Poor 
relative humidity recovery is also expected on Saturday night. 
Elevated fire weather conditions are possible on Sunday ahead of a
cold front for Sunday night. This cold front will be followed by 
gusty northwest winds as well as a chance of showers.

WYZ314-315-181700-
/O.CAN.KUNR.FW.W.0027.000000T0000Z-210918T0200Z/
/O.CON.KUNR.FW.W.0028.210918T1600Z-210919T0300Z/
Northern Campbell-Southern Campbell-
750 PM MDT Fri Sep 17 2021

...RED FLAG WARNING REMAINS IN EFFECT FROM 10 AM TO 9 PM MDT
SATURDAY FOR GUSTY WINDS AND LOW RELATIVE HUMIDITY FOR FIRE
WEATHER ZONES 314 AND 315...


* AFFECTED AREA...Fire Weather Zones 314 Northern Campbell and 
  315 Southern Campbell.

* WINDS...Southwest 20 to 30 mph with gusts up to 40 mph.

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

* IMPACTS...The combination of gusty winds and low relative 
  humidity would produce critical fire weather conditions.

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.

&&

$$

WYZ316>318-181700-
/O.CON.KUNR.FW.W.0028.210918T1600Z-210919T0300Z/
Crook County Plains-Weston County Plains-Wyoming Black Hills-
750 PM MDT Fri Sep 17 2021

...RED FLAG WARNING REMAINS IN EFFECT FROM 10 AM TO 9 PM MDT
SATURDAY FOR GUSTY WINDS AND LOW RELATIVE HUMIDITY FOR FIRE
WEATHER ZONES 316, 317, AND 318...

* AFFECTED AREA...Fire Weather Zones 316 Crook County Plains, 
  317 Weston County Plains and 318 Wyoming Black Hills.

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

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

* IMPACTS...The combination of gusty winds and low relative 
  humidity would produce critical fire weather conditions.

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.

&&

$$

SDZ323-327-181700-
/O.CON.KUNR.FW.W.0028.210918T1600Z-210919T0300Z/
Northern Foot Hills-Butte County Area-
750 PM MDT Fri Sep 17 2021

...RED FLAG WARNING REMAINS IN EFFECT FROM 10 AM TO 9 PM MDT
SATURDAY FOR GUSTY WINDS AND LOW RELATIVE HUMIDITY FOR FIRE
WEATHER ZONES 323 AND 327...

* AFFECTED AREA...Fire Weather Zones 323 Northern Foot Hills and 
  327 Butte County Area.

* WINDS...Southwest 10 to 20 mph with gusts up to 30 mph.

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

* IMPACTS...The combination of gusty winds and low relative 
  humidity would produce critical fire weather conditions.

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.

&&

$$

SDZ319>321-181700-
/O.CON.KUNR.FW.W.0028.210918T1600Z-210919T0300Z/
Northern Black Hills-Central Black Hills-Southern Black Hills-
750 PM MDT Fri Sep 17 2021

...RED FLAG WARNING REMAINS IN EFFECT FROM 10 AM TO 9 PM MDT
SATURDAY FOR GUSTY WINDS AND LOW RELATIVE HUMIDITY FOR FIRE
WEATHER ZONES 319, 320, AND 321...

* AFFECTED AREA...Fire Weather Zones 319 Northern Black Hills, 
  320 Central Black Hills and 321 Southern Black Hills.

* WINDS...Southwest 10 to 20 mph with gusts up to 30 mph.

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

* IMPACTS...The combination of gusty winds and low relative 
  humidity would produce critical fire weather conditions.

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.

&&

$$

SDZ322-324>326-328>333-181700-
/O.CON.KUNR.FW.W.0028.210918T1600Z-210919T0300Z/
Fall River County Area-Eastern Foot Hills-Custer County Plains-
Pine Ridge Area-Perkins County-West Central Plains-Ziebach County-
Haakon County Area-Badlands Area-Bennett County Area-
750 PM MDT Fri Sep 17 2021

...RED FLAG WARNING REMAINS IN EFFECT FROM 10 AM TO 9 PM MDT
SATURDAY FOR GUSTY WINDS AND LOW RELATIVE HUMIDITY FOR FIRE
WEATHER ZONES 322, 324, 325, 326, 328, 329, 330, 331, 332, AND
333...

* AFFECTED AREA...Fire Weather Zones 322 Fall River County Area, 
  324 Eastern Foot Hills, 325 Custer County Plains, 326 Pine 
  Ridge Area, 328 Perkins County, 329 West Central Plains, 330 
  Ziebach County, 331 Haakon County Area, 332 Badlands Area and 
  333 Bennett County Area.

* WINDS...South 10 to 20 mph with gusts up to 30 mph.

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

* IMPACTS...The combination of gusty winds and low relative 
  humidity would produce critical fire weather conditions.

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.

&&

$$
848 
WWUS83 KUNR 180817
RFWUNR

URGENT - FIRE WEATHER MESSAGE
National Weather Service Rapid City SD
217 AM MDT Sat Sep 18 2021

...RED FLAG WARNING IN EFFECT THIS MORNING THROUGH THIS EVENING 
FOR GUSTY WINDS AND LOW RELATIVE HUMIDITY FOR FIRE WEATHER ZONES 
314 THROUGH 333 IN NORTHEASTERN WYOMING AND WESTERN SOUTH 
DAKOTA...

.A strong surface trof moving through today will allow for very
deep mixing and hot/dry conditions developing. Relative humidity
will drop to around 10 percent for much of Northeast Wyoming and 
western SD. Southwest winds will gust up to 40 mph in Northeast 
Wyoming, and around 30 mph in western South Dakota, creating 
widespread critical fire weather conditions. Some gusty southwest 
winds will likely continue through tonight.

Near critical conditions will develop again on Sunday, with a
strong cold front moving through late in the afternoon and
evening. Very gusty northwest winds are likely behind the cold
front Sunday evening, with much cooler and unsettled weather 
expected for early next week.

WYZ314>318-190300-
/O.CON.KUNR.FW.W.0028.210918T1600Z-210919T0300Z/
Northern Campbell-Southern Campbell-Crook County Plains-
Weston County Plains-Wyoming Black Hills-
217 AM MDT Sat Sep 18 2021

...RED FLAG WARNING REMAINS IN EFFECT FROM 10 AM THIS MORNING TO
9 PM MDT THIS EVENING FOR GUSTY WINDS AND LOW RELATIVE HUMIDITY
FOR FIRE WEATHER ZONES 314, 315, 316, 317, AND 318...

* AFFECTED AREA...Fire Weather Zones 314 Northern Campbell, 315 
  Southern Campbell, 316 Crook County Plains, 317 Weston County 
  Plains and 318 Wyoming Black Hills.

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

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

* IMPACTS...The combination of gusty winds and low relative 
  humidity would produce critical fire weather conditions.

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.

&&

$$

SDZ323-327-190300-
/O.CON.KUNR.FW.W.0028.210918T1600Z-210919T0300Z/
Northern Foot Hills-Butte County Area-
217 AM MDT Sat Sep 18 2021

...RED FLAG WARNING REMAINS IN EFFECT FROM 10 AM THIS MORNING TO
9 PM MDT THIS EVENING FOR GUSTY WINDS AND LOW RELATIVE HUMIDITY
FOR FIRE WEATHER ZONES 323 AND 327...

* AFFECTED AREA...Fire Weather Zones 323 Northern Foot Hills and 
  327 Butte County Area.

* WINDS...Southwest 10 to 20 mph with gusts up to 30 mph.

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

* IMPACTS...The combination of gusty winds and low relative 
  humidity would produce critical fire weather conditions.

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.

&&

$$

SDZ319>321-190300-
/O.CON.KUNR.FW.W.0028.210918T1600Z-210919T0300Z/
Northern Black Hills-Central Black Hills-Southern Black Hills-
217 AM MDT Sat Sep 18 2021

...RED FLAG WARNING REMAINS IN EFFECT FROM 10 AM THIS MORNING TO
9 PM MDT THIS EVENING FOR GUSTY WINDS AND LOW RELATIVE HUMIDITY
FOR FIRE WEATHER ZONES 319, 320, AND 321...

* AFFECTED AREA...Fire Weather Zones 319 Northern Black Hills, 
  320 Central Black Hills and 321 Southern Black Hills.

* WINDS...Southwest 10 to 20 mph with gusts up to 30 mph.

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

* IMPACTS...The combination of gusty winds and low relative 
  humidity would produce critical fire weather conditions.

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.

&&

$$

SDZ322-324>326-328>333-190300-
/O.CON.KUNR.FW.W.0028.210918T1600Z-210919T0300Z/
Fall River County Area-Eastern Foot Hills-Custer County Plains-
Pine Ridge Area-Perkins County-West Central Plains-Ziebach County-
Haakon County Area-Badlands Area-Bennett County Area-
217 AM MDT Sat Sep 18 2021

...RED FLAG WARNING REMAINS IN EFFECT FROM 10 AM THIS MORNING TO
9 PM MDT THIS EVENING FOR GUSTY WINDS AND LOW RELATIVE HUMIDITY
FOR FIRE WEATHER ZONES 322, 324, 325, 326, 328, 329, 330, 331,
332, AND 333...

* AFFECTED AREA...Fire Weather Zones 322 Fall River County Area, 
  324 Eastern Foot Hills, 325 Custer County Plains, 326 Pine 
  Ridge Area, 328 Perkins County, 329 West Central Plains, 330 
  Ziebach County, 331 Haakon County Area, 332 Badlands Area and 
  333 Bennett County Area.

* WINDS...South 10 to 20 mph with gusts up to 30 mph.

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

* IMPACTS...The combination of gusty winds and low relative 
  humidity would produce critical fire weather conditions.

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.

&&

$$
009 
WWUS83 KUNR 181701
RFWUNR

URGENT - FIRE WEATHER MESSAGE
National Weather Service Rapid City SD
1101 AM MDT Sat Sep 18 2021

...RED FLAG WARNING IN EFFECT THROUGH THIS EVENING FOR GUSTY 
WINDS AND LOW RELATIVE HUMIDITY FOR FIRE WEATHER ZONES 314 THROUGH
333 IN NORTHEASTERN WYOMING AND WESTERN SOUTH DAKOTA...

.The weather today will be hot, dry and windy. The relative 
humidity will drop to around 10 percent over northeastern Wyoming
and much of western South Dakota. Southwesterly winds will gust 
up to 40 mph in northeastern Wyoming, and to around 30 mph in 
western South Dakota, creating widespread critical fire weather 
conditions. Gusty southwest winds may continue through tonight 
over parts of northeastern Wyoming.

Near critical conditions will develop again on Sunday, with a
strong cold front moving through late in the afternoon and
evening. Very gusty northwest winds are likely behind the cold
front Sunday evening, with much cooler and unsettled weather
expected for early next week.

WYZ314>318-190300-
/O.CON.KUNR.FW.W.0028.000000T0000Z-210919T0300Z/
Northern Campbell-Southern Campbell-Crook County Plains-
Weston County Plains-Wyoming Black Hills-
1101 AM MDT Sat Sep 18 2021

...RED FLAG WARNING REMAINS IN EFFECT UNTIL 9 PM MDT THIS EVENING
FOR GUSTY WINDS AND LOW RELATIVE HUMIDITY FOR FIRE WEATHER ZONES
314, 315, 316, 317, AND 318...

* AFFECTED AREA...Fire Weather Zones 314 Northern Campbell, 315 
  Southern Campbell, 316 Crook County Plains, 317 Weston County 
  Plains and 318 Wyoming Black Hills.

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

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

* IMPACTS...The combination of gusty winds and low relative 
  humidity would produce critical fire weather conditions.

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.

&&

$$

SDZ323-327-190300-
/O.CON.KUNR.FW.W.0028.000000T0000Z-210919T0300Z/
Northern Foot Hills-Butte County Area-
1101 AM MDT Sat Sep 18 2021

...RED FLAG WARNING REMAINS IN EFFECT UNTIL 9 PM MDT THIS EVENING
FOR GUSTY WINDS AND LOW RELATIVE HUMIDITY FOR FIRE WEATHER ZONES
323 AND 327...

* AFFECTED AREA...Fire Weather Zones 323 Northern Foot Hills and 
  327 Butte County Area.

* WINDS...Southwest 10 to 20 mph with gusts up to 30 mph.

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

* IMPACTS...The combination of gusty winds and low relative 
  humidity would produce critical fire weather conditions.

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.

&&

$$

SDZ319>321-190300-
/O.CON.KUNR.FW.W.0028.000000T0000Z-210919T0300Z/
Northern Black Hills-Central Black Hills-Southern Black Hills-
1101 AM MDT Sat Sep 18 2021

...RED FLAG WARNING REMAINS IN EFFECT UNTIL 9 PM MDT THIS EVENING
FOR GUSTY WINDS AND LOW RELATIVE HUMIDITY FOR FIRE WEATHER ZONES
319, 320, AND 321...

* AFFECTED AREA...Fire Weather Zones 319 Northern Black Hills, 
  320 Central Black Hills and 321 Southern Black Hills.

* WINDS...Southwest 10 to 20 mph with gusts up to 30 mph.

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

* IMPACTS...The combination of gusty winds and low relative 
  humidity would produce critical fire weather conditions.

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.

&&

$$

SDZ322-324>326-328>333-190300-
/O.CON.KUNR.FW.W.0028.000000T0000Z-210919T0300Z/
Fall River County Area-Eastern Foot Hills-Custer County Plains-
Pine Ridge Area-Perkins County-West Central Plains-Ziebach County-
Haakon County Area-Badlands Area-Bennett County Area-
1101 AM MDT Sat Sep 18 2021

...RED FLAG WARNING REMAINS IN EFFECT UNTIL 9 PM MDT THIS EVENING
FOR GUSTY WINDS AND LOW RELATIVE HUMIDITY FOR FIRE WEATHER ZONES
322, 324, 325, 326, 328, 329, 330, 331, 332, AND 333...

* AFFECTED AREA...Fire Weather Zones 322 Fall River County Area, 
  324 Eastern Foot Hills, 325 Custer County Plains, 326 Pine 
  Ridge Area, 328 Perkins County, 329 West Central Plains, 330 
  Ziebach County, 331 Haakon County Area, 332 Badlands Area and 
  333 Bennett County Area.

* WINDS...South 10 to 20 mph with gusts up to 30 mph.

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

* IMPACTS...The combination of gusty winds and low relative 
  humidity would produce critical fire weather conditions.

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.

&&

$$
365 
WWUS83 KUNR 181942
RFWUNR

URGENT - FIRE WEATHER MESSAGE
National Weather Service Rapid City SD
142 PM MDT Sat Sep 18 2021

...RED FLAG WARNING REMAINS IN EFFECT THROUGH THIS EVENING FOR 
GUSTY WINDS AND LOW RELATIVE HUMIDITY FOR FIRE WEATHER ZONES 314 
THROUGH 333 IN NORTHEASTERN WYOMING AND WESTERN SOUTH DAKOTA...

.Hot, dry and windy weather will continue through the rest of the
afternoon and into the evening. With the relative humidity around
10 percent over northeastern Wyoming and much of western South 
Dakota, along with gusty southwesterly winds, critical fire 
weather conditions have developed. The relative humidity will 
improve slightly as temperatures begin to cool this evening. 
Gusty southwest winds may continue through the night over parts of
northeastern Wyoming.

Near critical fire weather conditions will develop on Sunday, 
with a strong cold front moving through late in the afternoon and 
evening. Very gusty northwest winds are likely behind the cold 
front on Sunday evening, with much cooler and unsettled weather 
expected for early next week.

WYZ314>318-190300-
/O.CON.KUNR.FW.W.0028.000000T0000Z-210919T0300Z/
Northern Campbell-Southern Campbell-Crook County Plains-
Weston County Plains-Wyoming Black Hills-
142 PM MDT Sat Sep 18 2021

...RED FLAG WARNING REMAINS IN EFFECT UNTIL 9 PM MDT THIS EVENING
FOR GUSTY WINDS AND LOW RELATIVE HUMIDITY FOR FIRE WEATHER ZONES
314, 315, 316, 317, AND 318...

* AFFECTED AREA...Fire Weather Zones 314 Northern Campbell, 315 
  Southern Campbell, 316 Crook County Plains, 317 Weston County 
  Plains and 318 Wyoming Black Hills.

* WINDS...Southwest 15 to 30 mph with gusts up to 35 mph.

* RELATIVE HUMIDITY...As low as 8 percent.

* IMPACTS...The combination of gusty winds and low relative
  humidity have created critical fire weather conditions.

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.

&&

$$

SDZ323-327-190300-
/O.CON.KUNR.FW.W.0028.000000T0000Z-210919T0300Z/
Northern Foot Hills-Butte County Area-
142 PM MDT Sat Sep 18 2021

...RED FLAG WARNING REMAINS IN EFFECT UNTIL 9 PM MDT THIS EVENING
FOR GUSTY WINDS AND LOW RELATIVE HUMIDITY FOR FIRE WEATHER ZONES
323 AND 327...

* AFFECTED AREA...Fire Weather Zones 323 Northern Foot Hills and 
  327 Butte County Area.

* WINDS...Southwest 10 to 20 mph with gusts up to 30 mph.

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

* IMPACTS...The combination of gusty winds and low relative
  humidity have created critical fire weather conditions.

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.

&&

$$

SDZ319>321-190300-
/O.CON.KUNR.FW.W.0028.000000T0000Z-210919T0300Z/
Northern Black Hills-Central Black Hills-Southern Black Hills-
142 PM MDT Sat Sep 18 2021

...RED FLAG WARNING REMAINS IN EFFECT UNTIL 9 PM MDT THIS EVENING
FOR GUSTY WINDS AND LOW RELATIVE HUMIDITY FOR FIRE WEATHER ZONES
319, 320, AND 321...

* AFFECTED AREA...Fire Weather Zones 319 Northern Black Hills, 
  320 Central Black Hills and 321 Southern Black Hills.

* WINDS...Southwest 10 to 20 mph with gusts up to 30 mph.

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

* IMPACTS...The combination of gusty winds and low relative
  humidity have created critical fire weather conditions.

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.

&&

$$

SDZ322-324>326-328>333-190300-
/O.CON.KUNR.FW.W.0028.000000T0000Z-210919T0300Z/
Fall River County Area-Eastern Foot Hills-Custer County Plains-
Pine Ridge Area-Perkins County-West Central Plains-Ziebach County-
Haakon County Area-Badlands Area-Bennett County Area-
142 PM MDT Sat Sep 18 2021

...RED FLAG WARNING REMAINS IN EFFECT UNTIL 9 PM MDT THIS EVENING
FOR GUSTY WINDS AND LOW RELATIVE HUMIDITY FOR FIRE WEATHER ZONES
322, 324, 325, 326, 328, 329, 330, 331, 332, AND 333...

* AFFECTED AREA...Fire Weather Zones 322 Fall River County Area, 
  324 Eastern Foot Hills, 325 Custer County Plains, 326 Pine 
  Ridge Area, 328 Perkins County, 329 West Central Plains, 330 
  Ziebach County, 331 Haakon County Area, 332 Badlands Area and 
  333 Bennett County Area.

* WINDS...South 10 to 20 mph with gusts up to 30 mph.

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

* IMPACTS...The combination of gusty winds and low relative
  humidity have created critical fire weather conditions.

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.

&&

$$
624 
WWUS83 KUNR 190256
RFWUNR

URGENT - FIRE WEATHER MESSAGE
National Weather Service Rapid City SD
856 PM MDT Sat Sep 18 2021

WYZ314>318-190400-
/O.EXP.KUNR.FW.W.0028.000000T0000Z-210919T0300Z/
Northern Campbell-Southern Campbell-Crook County Plains-
Weston County Plains-Wyoming Black Hills-
856 PM MDT Sat Sep 18 2021

...RED FLAG WARNING WILL EXPIRE AT 9 PM MDT THIS EVENING FOR
GUSTY WINDS AND LOW RELATIVE HUMIDITY FOR FIRE WEATHER ZONES 314,
315, 316, 317, AND 318...

$$

SDZ323-327-190400-
/O.EXP.KUNR.FW.W.0028.000000T0000Z-210919T0300Z/
Northern Foot Hills-Butte County Area-
856 PM MDT Sat Sep 18 2021

...RED FLAG WARNING WILL EXPIRE AT 9 PM MDT THIS EVENING FOR
GUSTY WINDS AND LOW RELATIVE HUMIDITY FOR FIRE WEATHER ZONES
323 AND 327...

$$

SDZ319>321-190400-
/O.EXP.KUNR.FW.W.0028.000000T0000Z-210919T0300Z/
Northern Black Hills-Central Black Hills-Southern Black Hills-
856 PM MDT Sat Sep 18 2021

...RED FLAG WARNING WILL EXPIRE AT 9 PM MDT THIS EVENING FOR
GUSTY WINDS AND LOW RELATIVE HUMIDITY FOR FIRE WEATHER ZONES 319,
320, AND 321...

$$

SDZ322-324>326-328>333-190400-
/O.EXP.KUNR.FW.W.0028.000000T0000Z-210919T0300Z/
Fall River County Area-Eastern Foot Hills-Custer County Plains-
Pine Ridge Area-Perkins County-West Central Plains-Ziebach County-
Haakon County Area-Badlands Area-Bennett County Area-
856 PM MDT Sat Sep 18 2021

...RED FLAG WARNING WILL EXPIRE AT 9 PM MDT THIS EVENING FOR
GUSTY WINDS AND LOW RELATIVE HUMIDITY FOR FIRE WEATHER ZONES 322,
324, 325, 326, 328, 329, 330, 331, 332, AND 333...

$$

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 Rapid City, SD wrote its last area forecast discussion before this red flag warning went out at Sep 17, 11:15 AM MDT, 2 hours 2 minutes earlier.

Area forecast discussion, Sep 17, 11:15 AM MDT, 2 hours 2 minutes before
Area Forecast Discussion For Western SD and Northeastern WY
National Weather Service Rapid City SD
1115 AM MDT Fri Sep 17 2021

.DISCUSSION...(Today Through Thursday)
Issued at 216 AM MDT Fri Sep 17 2021

08z surface analysis had high over MT pushing cold front well
south of the CWA, currently located from northern CO into southern
MN. Water vapour had shortwave trough moving across the northern
plains with some AC/SC under associated jet streak over the CWA.

Today/tonight, surface high moves southeast with robust return flow
over the area. 3-4mb/3hr pressure falls over eastern MT will
support gusty southerly winds over northeast WY spreading into
western SD. Temperatures will be near guidance.

Saturday/Sunday, progressive westerly flow aloft becomes
southwesterly in response to upper trough developing over the
northwest CONUS. This trough will move into the northern Rockies
Sunday. Thermal ridge builds into the CWA with highs 10-20F above
normal. Gusty west/southwest winds expected due to very deep
boundary layer mixing.

Sunday night through Tuesday, upper trough moves across the northern
plains into south central Canada. Latest ensemble guidance indicates
system has sped up with less moisture return. Still looks like it
will precipitate, but not as much as previously thought. Sharp cold
front moves through Sunday night with potentially strong/gusty
northwest winds behind it. Thermal profiles suggest a bit of snow up
high with little to no accumulation.

The second half of next week will feature seasonal, typical
mostly dry Fall weather.

&&

.AVIATION...(For the 18Z TAFS Through 18Z Saturday)
Issued At 1112 AM MDT Fri Sep 17 2021

VFR conditions are expected through the period. Gusty southerly
winds will continue this afternoon, with a slight decrease in
wind speeds this evening and on Saturday.

&&

.FIRE WEATHER...
Issued At 216 AM MDT Fri Sep 17 2021

Robust southerly winds are expected today across northeast WY
into western SD. Minimum relative humidities will drop to 15-25%
with readings 15% or below over fire weather zones 314/315, where
a Red Flag Warning will be issued. Elevated fire weather
conditions expected elsewhere.

Saturday/Sunday may be critical fire weather days with unseasonably
warm temperatures, gusty west/southwest winds and very dry air in
place. Some uncertainty with how dry/windy Sunday will be so, will
hoist Fire Weather Watch only for Saturday at this time.

&&

.UNR WATCHES/WARNINGS/ADVISORIES...
SD...Fire Weather Watch from Saturday morning through Saturday
     evening for SDZ321>333.

WY...Fire Weather Watch from Saturday morning through Saturday
     evening for WYZ314>318.

     Red Flag Warning until 8 PM MDT this evening for WYZ314-315.

&&

DISCUSSION...Helgeson
AVIATION...MLS
FIRE WEATHER...Helgeson
Hazardous weather outlook, Sep 17, 5:00 AM MDT, 8 hours 17 minutes before
Hazardous Weather Outlook
National Weather Service Rapid City SD
500 AM MDT Fri Sep 17 2021

WYZ054-055-181100-
Northern Campbell-Southern Campbell-
500 AM MDT Fri Sep 17 2021

This Hazardous Weather Outlook is for portions of northeast
Wyoming.

.DAY ONE...Today and Tonight

Critical fire weather conditions are expected this afternoon and
early evening due to low relative humidities and southerly winds
at 20 to 30 mph gusting to 45 mph.

.DAYS TWO THROUGH SEVEN...Saturday through Thursday

Critical fire weather conditions are possible Saturday with
elevated fire weather conditions for Sunday.

.SPOTTER INFORMATION STATEMENT...

Spotter activation will not be needed today.

&&

Stay tuned to NOAA weather radio for further updates...or check
our web site at weather.gov/rapidcity

SDZ046-047-049-181100-
Mellette-Todd-Tripp-
600 AM CDT Fri Sep 17 2021

This Hazardous Weather Outlook is for portions of south central
South Dakota.

.DAY ONE...Today and Tonight

No hazardous weather is expected at this time.

.DAYS TWO THROUGH SEVEN...Saturday through Thursday

No hazardous weather is expected at this time.

.SPOTTER INFORMATION STATEMENT...

Spotter activation will not be needed today.

&&

Stay tuned to NOAA weather radio for further updates...or check
our web site at weather.gov/rapidcity

SDZ001-002-012>014-024>032-041>044-072>074-WYZ056>058-071-181100-
Harding-Perkins-Butte-Northern Meade Co Plains-Ziebach-
Northern Black Hills-Northern Foot Hills-Rapid City-
Southern Foot Hills-Central Black Hills-Southern Black Hills-
Custer Co Plains-Pennington Co Plains-Haakon-Fall River-
Oglala Lakota-Jackson-Bennett-Sturgis/Piedmont Foot Hills-
Southern Meade Co Plains-Hermosa Foot Hills-Western Crook-
Wyoming Black Hills-Weston-Northeastern Crook-
500 AM MDT Fri Sep 17 2021

This Hazardous Weather Outlook is for portions of western South
Dakota and northeastern Wyoming.

.DAY ONE...Today and Tonight

Elevated fire weather conditions are expected today due to gusty
southerly winds and dry air. The grassland fire danger index will
be high to very high this afternoon on the South Dakota plains.

.DAYS TWO THROUGH SEVEN...Saturday through Thursday

Critical fire weather conditions are possible Saturday due to
gusty west to southwest winds and very dry air.

.SPOTTER INFORMATION STATEMENT...

Spotter activation will not be needed today.

&&

Stay tuned to NOAA weather radio for further updates...or check
our web site at weather.gov/rapidcity

The office that day

Everything else NWS Rapid City, SD issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Sep 17, 2:44 AM MDTFire Weather WatchUNRCampbell, Crook, Weston11 hr
Sep 17, 2:44 AM MDTRed Flag WarningUNRCampbell17 hr
Sep 16, 7:25 PM MDTSpecial Weather StatementUNRTodd50 min
Sep 16, 8:00 PM MDTSpecial Weather StatementUNRTodd30 min
Sep 16, 8:14 PM MDTSpecial Weather StatementUNRTripp31 min
Sep 16, 8:35 PM MDTSpecial Weather StatementUNRTripp25 min

Nearby

Red Flag Warnings in South Dakota, 2021Red Flag Warnings in Wyoming, 2021Every red flag warning in 2021

Sources

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