Alert archive / South Dakota / Red Flag Warnings in 2021

Red Flag Warning 21, NWS Aberdeen, SD

September 18, 20214 counties in South Dakota

NWS Aberdeen, SD issued this red flag warning at Sep 18, 2021, 8:26 AM MDT for 4 counties in South Dakota. It took effect at Sep 18, 2021, 11:00 AM MDT. It was in force for 8 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 18, 2021, 8:26 AM MDT (14:26 UTC)
In effect from
Sep 18, 2021, 11:00 AM MDT
Expired
Sep 18, 2021, 7:00 PM MDT
In force
8 hr
Issued by
NWS Aberdeen, SD

Counties Corson County, SD, Dewey County, SD, Jones County, SD, Stanley County, SD

The radar

The Rapid City radar (KUDX), 173 km from the middle of the area, began a volume at 14:29 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

Rapid City, SD (KUNR), launched 12:00Z, 2.4 hours before the alert went out and 179 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 2021-09-18Temperature 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°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Rapid City, SD at 12:00Z on 2021-09-18The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 58 square meters per square second.1939Sfc1 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
3699 m above ground
0-6 km bulk shear
16 kt
0-1 km storm-relative helicity
58 m²/s²
0-3 km storm-relative helicity
109 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

143 
WWUS83 KABR 181426
RFWABR

URGENT - FIRE WEATHER MESSAGE
National Weather Service Aberdeen SD
926 AM CDT Sat Sep 18 2021

SDZ003-015-033-045-182230-
/O.NEW.KABR.FW.W.0021.210918T1700Z-210919T0100Z/
Corson-Dewey-Stanley-Jones-
926 AM CDT Sat Sep 18 2021 /826 AM MDT Sat Sep 18 2021/

...RED FLAG WARNING IN EFFECT UNTIL 8 PM CDT /7 PM MDT/ THIS
EVENING FOR WIND AND LOW RELATIVE HUMIDITY FOR PORTIONS OF CENTRAL
AND NORTH CENTRAL SOUTH DAKOTA...

The National Weather Service in Aberdeen has issued a Red Flag
Warning for wind and low relative humidity, which is in effect
until 8 PM CDT /7 PM MDT/ this evening.

* AFFECTED AREA...In South Dakota, Corson, Dewey, Stanley and 
  Jones.

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

* RELATIVE HUMIDITY...As low as 17 percent.

* IMPACTS...The combination of gusty winds and low relative 
  humidity will be supportive of rapid fire growth. Any fires 
  will become difficult to control and suppress.

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.

&&

$$
1 follow-up statement
849 
WWUS83 KABR 182133
RFWABR

URGENT - FIRE WEATHER MESSAGE
National Weather Service Aberdeen SD
433 PM CDT Sat Sep 18 2021

SDZ003-015-033-045-190100-
/O.CON.KABR.FW.W.0021.000000T0000Z-210919T0100Z/
Corson-Dewey-Stanley-Jones-
433 PM CDT Sat Sep 18 2021 /333 PM MDT Sat Sep 18 2021/

...RED FLAG WARNING REMAINS IN EFFECT UNTIL 8 PM CDT /7 PM MDT/
THIS EVENING FOR WIND AND LOW RELATIVE HUMIDITY FOR PORTIONS OF
CENTRAL AND NORTH CENTRAL SOUTH DAKOTA...

* AFFECTED AREA...In South Dakota, Corson, Dewey, Stanley and 
  Jones.

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

* RELATIVE HUMIDITY...As low as 18 percent.

* IMPACTS...The combination of gusty winds and low relative 
  humidity will be supportive of rapid fire growth. Any fires 
  will become difficult to control and suppress.

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.

&&

$$

Mohr

Nearby

Red Flag Warnings in South Dakota, 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; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.