Alert archive / Iowa / Severe Thunderstorm Warnings in 2021

Severe Thunderstorm Warning 152, NWS Omaha, NE

August 25, 2021Mills County, Montgomery County, Pottawattamie County, Iowa

NWS Omaha, NE issued this severe thunderstorm warning at Aug 25, 2021, 1:58 AM CDT for Mills County, Montgomery County, Pottawattamie County, Iowa. It was in force for 32 min. No storm report in the archive falls inside the area while it was in force.

The area

The outline as issued.

The facts

Issued
Aug 25, 2021, 1:58 AM CDT (06:58 UTC)
Expired
Aug 25, 2021, 2:30 AM CDT
In force
32 min
Issued by
NWS Omaha, NE
Area
Storm-based polygon
Hail
0.75 in
Wind
60.0 mph

Counties Mills County, IA, Montgomery County, IA, Pottawattamie County, IA

The radar

The Omaha radar (KOAX), 102 km from the middle of the area, began a volume at 07:01 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 00:00Z, 7.0 hours before the alert went out and 102 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 00:00Z on 2021-08-25Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 3303 joules per kilogram.LCLLFCEL10008507005003002001001 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 00:00Z on 2021-08-25The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 79 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
3303 J/kg
Mixed-layer CIN
-92 J/kg
Mixed-layer LCL
1689 m above ground
0-6 km bulk shear
24 kt
0-1 km storm-relative helicity
79 m²/s²
0-3 km storm-relative helicity
138 m²/s²
Significant tornado parameter
0.3
Supercell composite
8.5

Open this sounding in Storm Lab

The text

As transmitted.

347 
WUUS53 KOAX 250658
SVROAX
IAC129-137-155-250730-
/O.NEW.KOAX.SV.W.0152.210825T0658Z-210825T0730Z/

BULLETIN - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Warning
National Weather Service Omaha/Valley Nebraska
158 AM CDT Wed Aug 25 2021

The National Weather Service in Omaha has issued a

* Severe Thunderstorm Warning for...
  Montgomery County in southwestern Iowa...
  East central Mills County in southwestern Iowa...
  Southeastern Pottawattamie County in southwestern Iowa...

* Until 230 AM CDT.

* At 157 AM CDT, a severe thunderstorm was located near Red Oak, or
  29 miles west of Corning, moving northeast at 20 mph.

  HAZARD...60 mph wind gusts and penny size hail.

  SOURCE...Radar indicated.

  IMPACT...Expect damage to roofs, siding, and trees.

* This severe thunderstorm will be near...
  Red Oak around 205 AM CDT.

Other locations in the path of this severe thunderstorm include
Elliott.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

For your protection move to an interior room on the lowest floor of a
building.

&&

LAT...LON 4103 9497 4090 9526 4090 9535 4102 9545
      4124 9528
TIME...MOT...LOC 0657Z 221DEG 19KT 4102 9531 

HAIL THREAT...RADAR INDICATED
MAX HAIL SIZE...0.75 IN
WIND THREAT...RADAR INDICATED
MAX WIND GUST...60 MPH

$$

Petersen
1 follow-up statement
435 
WWUS53 KOAX 250726
SVSOAX

Severe Weather Statement
National Weather Service Omaha/Valley Nebraska
226 AM CDT Wed Aug 25 2021

IAC129-137-155-250736-
/O.EXP.KOAX.SV.W.0152.000000T0000Z-210825T0730Z/
Montgomery IA-Mills IA-Pottawattamie IA-
226 AM CDT Wed Aug 25 2021

...THE SEVERE THUNDERSTORM WARNING FOR MONTGOMERY...EAST CENTRAL
MILLS AND SOUTHEASTERN POTTAWATTAMIE COUNTIES WILL EXPIRE AT 230 AM
CDT...
                
The storm which prompted the warning has weakened below severe
limits, and no longer poses an immediate threat to life or property.
Therefore, the warning will be allowed to expire.

LAT...LON 4103 9497 4090 9526 4090 9535 4102 9545
      4124 9528
TIME...MOT...LOC 0726Z 221DEG 19KT 4113 9518 

$$

Albright

The office that day

Everything else NWS Omaha, NE issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Aug 25, 12:43 AM CDTSevere Thunderstorm WarningOAXMills, Pottawattamie47 min
Aug 25, 1:00 AM CDTSevere Thunderstorm WarningOAXPottawattamie24 min
Aug 25, 1:16 AM CDTSevere Thunderstorm WarningOAXFremont, Mills44 min
Aug 25, 1:25 AM CDTSevere Thunderstorm WarningOAXMills, Montgomery, Pottawattamie50 min
Aug 25, 1:53 AM CDTSevere Thunderstorm WarningOAXFremont, Mills37 min
Aug 25, 4:07 AM CDTHeat AdvisoryOAXFremont, Harrison, Mills, Montgomery, Page, Pottawattamie and 1 more40 hr

Nearby

Severe Thunderstorm Warnings in Iowa, 2021Every severe thunderstorm 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.