Alert archive / Iowa / Red Flag Warnings in 2020

Red Flag Warning 3, NWS Sioux Falls, SD

September 29, 20207 counties in Iowa

NWS Sioux Falls, SD issued this red flag warning at Sep 29, 2020, 10:47 AM CDT for 7 counties in Iowa. It took effect at Sep 29, 2020, 1:00 PM CDT. It was in force for 6 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 29, 2020, 10:47 AM CDT (15:47 UTC)
In effect from
Sep 29, 2020, 1:00 PM CDT
Expired
Sep 29, 2020, 7:00 PM CDT
In force
6 hr
Issued by
NWS Sioux Falls, SD

Counties Cherokee County, IA, Ida County, IA, Lyon County, IA, O'Brien County, IA, Plymouth County, IA, Sioux County, IA, Woodbury County, IA

The radar

The Sioux Falls radar (KFSD), 107 km from the middle of the area, began a volume at 15:47 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

Omaha, NE (KOAX), launched 12:00Z, 3.8 hours before the alert went out and 172 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, Omaha, NE at 12:00Z on 2020-09-29Temperature 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, Omaha, NE at 12:00Z on 2020-09-29The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 103 square meters per square second.1939587897117136Sfc1 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
1493 m above ground
0-6 km bulk shear
72 kt
0-1 km storm-relative helicity
103 m²/s²
0-3 km storm-relative helicity
170 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

196 
WWUS83 KFSD 291547
RFWFSD

URGENT - FIRE WEATHER MESSAGE
National Weather Service Sioux Falls SD
1047 AM CDT Tue Sep 29 2020

...RED FLAG WARNING IS IN EFFECT FROM 1PM to 7PM THIS EVENING FOR
PORTIONS OF SOUTHEAST SOUTH DAKOTA AND FAR WESTERN IOWA...

IAZ012-020-031-NEZ249-SDZ258-300000-
/O.NEW.KFSD.FW.W.0003.200929T1800Z-200930T0000Z/
Sioux-Plymouth-Woodbury-Extreme Northeast Nebraska-
Lower James River To Lower Big Sioux River Valley-
1047 AM CDT Tue Sep 29 2020

...RED FLAG WARNING IN EFFECT UNTIL 7 PM CDT THIS EVENING FOR
STRONG WINDS AND LOW HUMIDITY FOR FIRE WEATHER ZONES 012, 020, 
031, 249, AND 258...

The National Weather Service in Sioux Falls has issued a Red Flag
Warning, which is in effect until 7 PM CDT this evening. 

* AFFECTED AREA...Fire weather zones 012, 020, and 031. Fire 
  weather zone 249. Fire weather zone 258. 

* WIND...Westerly winds will increase between 20 and 25 mph by
  early afternoon gusting to 35 mph at times. Winds will begin to
  turn northwesterly by mid-afternoon with strong gusts
  continuing.

* HUMIDITY...Lowest afternoon relative humidity values will be
  between 22 and 27 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.

&&

$$
2 follow-up statements
962 
WWUS83 KFSD 291912
RFWFSD

URGENT - FIRE WEATHER MESSAGE
National Weather Service Sioux Falls SD
212 PM CDT Tue Sep 29 2020

...RED FLAG WARNING IS IN EFFECT FROM 1PM to 7PM THIS EVENING FOR
PORTIONS OF SOUTHEAST SOUTH DAKOTA NORTHEAST NEBRASKA AND
NORTHWESTERN IOWA...

IAZ001-013-021-032-300000-
/O.EXA.KFSD.FW.W.0003.000000T0000Z-200930T0000Z/
Lyon-O'Brien-Cherokee-Ida-
212 PM CDT Tue Sep 29 2020

...RED FLAG WARNING IN EFFECT UNTIL 7 PM CDT THIS EVENING FOR
STRONG WINDS AND LOW HUMIDITY FOR FIRE WEATHER ZONES 012, 020,
031, 249, AND 258...

The National Weather Service in Sioux Falls has issued a Red Flag
Warning, which is in effect until 7 PM CDT this evening. 

* AFFECTED AREA...Fire weather zones 012, 020, and 031. Fire 
  weather zone 249. Fire weather zone 258. 

* WIND...Westerly winds will increase between 20 and 25 mph by 
  early afternoon gusting to 35 mph at times. Winds will begin 
  to turn northwesterly by mid-afternoon with strong gusts 
  continuing.

* HUMIDITY...Lowest afternoon relative humidity values will be 
  between 22 and 27 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.

&&

$$

IAZ012-020-031-NEZ249-SDZ258-300000-
/O.CON.KFSD.FW.W.0003.000000T0000Z-200930T0000Z/
Sioux-Plymouth-Woodbury-Extreme Northeast Nebraska-
Lower James River To Lower Big Sioux River Valley-
212 PM CDT Tue Sep 29 2020

...RED FLAG WARNING REMAINS IN EFFECT UNTIL 7 PM CDT THIS EVENING
FOR STRONG WINDS AND LOW HUMIDITY FOR FIRE WEATHER ZONES 012,
020, 031, 249, AND 258...

* AFFECTED AREA...Fire weather zones 012, 020, and 031. Fire 
  weather zone 249. Fire weather zone 258. 

* WIND...Westerly winds will increase between 20 and 25 mph by 
  early afternoon gusting to 35 mph at times. Winds will begin 
  to turn northwesterly by mid-afternoon with strong gusts 
  continuing.

* HUMIDITY...Lowest afternoon relative humidity values will be 
  between 22 and 27 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.

&&

$$
710 
WWUS83 KFSD 292353
RFWFSD

URGENT - FIRE WEATHER MESSAGE
National Weather Service Sioux Falls SD
653 PM CDT Tue Sep 29 2020

IAZ001-012-013-020-021-031-032-NEZ249-SDZ258-300100-
/O.EXP.KFSD.FW.W.0003.000000T0000Z-200930T0000Z/
Lyon-Sioux-O'Brien-Plymouth-Cherokee-Woodbury-Ida-
Extreme Northeast Nebraska-
Lower James River To Lower Big Sioux River Valley-
653 PM CDT Tue Sep 29 2020

...RED FLAG WARNING WILL EXPIRE AT 7 PM CDT THIS EVENING FOR HIGH
WINDS AND LOW HUMIDITY FOR FIRE WEATHER ZONES 001, 012, 013, 020,
021, 031, 032, 249, AND 258...

Relative humidities across the region have improved from their
mid-afternoon low points, and winds are beginning to taper off as
mixing decreases.

$$

The office that day

Everything else NWS Sioux Falls, SD issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Sep 29, 2:36 PM CDTWind AdvisoryFSDBuena Vista, Cherokee, Clay, Dickinson, Ida, Lyon and 5 more29 hr

Nearby

Red Flag Warnings in Iowa, 2020Red Flag Warnings in Nebraska, 2020Red Flag Warnings in South Dakota, 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.