Alert archive / Iowa / Severe Thunderstorm Warnings in 2021

Severe Thunderstorm Warning 151, NWS Omaha, NE

August 25, 2021Fremont County, Mills County, Iowa; Cass County, Otoe County, Nebraska

NWS Omaha, NE issued this severe thunderstorm warning at Aug 25, 2021, 1:53 AM CDT for Fremont County, Mills County, Iowa; Cass County, Otoe County, Nebraska. It was in force for 37 min. 1 report came from inside the area while it was in force.

The area

The outline as issued, with what was reported inside it.

The facts

Issued: Aug 25, 2021, 1:53 AM CDT (06:53 UTC)
Expired: Aug 25, 2021, 2:30 AM CDT
In force: 37 min
Issued by: NWS Omaha, NE
Area: Storm-based polygon
Hail: 0.75 in
Wind: 60.0 mph

Counties Fremont County, IA, Mills County, IA, Cass County, NE, Otoe County, NE

The radar

The Omaha radar (KOAX), 92 km from the middle of the area, began a volume at 06:55 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

Time	Report	Where	Remark
Aug 25, 1:55 AM CDT	TSTM WND GST 60	3 Wnw Thurman, IA

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

The nearest sounding before it

Omaha, NE (KOAX), launched 00:00Z, 6.9 hours before the alert went out and 92 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-p

Temperature in red, dew point in green, the mixed-layer parcel dashed.

Hodograph

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.

616 
WUUS53 KOAX 250653
SVROAX
IAC071-129-NEC025-131-250730-
/O.NEW.KOAX.SV.W.0151.210825T0653Z-210825T0730Z/

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

The National Weather Service in Omaha has issued a

* Severe Thunderstorm Warning for...
  Fremont County in southwestern Iowa...
  Southern Mills County in southwestern Iowa...
  Northeastern Otoe County in southeastern Nebraska...
  Southeastern Cass County in southeastern Nebraska...

* Until 230 AM CDT.

* At 151 AM CDT, severe thunderstorms were located along a line
  extending from 7 miles southeast of Pacific Junction to Nebraska
  City, moving southeast at 40 mph.

  HAZARD...60 mph wind gusts.

  SOURCE...Radar indicated.

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

* Severe thunderstorms will be near...
  Sidney around 205 AM CDT.
  Hamburg around 210 AM CDT.

Other locations in the path of these severe thunderstorms include
Tabor, Shenandoah, Randalph, Sidney, Riverton and Farragut.

This includes Interstate 29 between mile markers 1 and 32.
 
PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 4058 9564 4059 9566 4058 9566 4058 9573
      4067 9600 4101 9581 4102 9538 4058 9538
TIME...MOT...LOC 0651Z 302DEG 36KT 4092 9574 4068 9589 

HAIL THREAT...RADAR INDICATED
MAX HAIL SIZE...<.75 IN
WIND THREAT...RADAR INDICATED
MAX WIND GUST...60 MPH

$$

Petersen

2 follow-up statements

179 
WWUS53 KOAX 250709
SVSOAX

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

NEC025-250717-
/O.CAN.KOAX.SV.W.0151.000000T0000Z-210825T0730Z/
Cass NE-
209 AM CDT Wed Aug 25 2021

...THE SEVERE THUNDERSTORM WARNING FOR SOUTHEASTERN CASS COUNTY IS
CANCELLED...

The storms which prompted the warning have moved out of the warned 
area. Therefore, the warning has been cancelled.

LAT...LON 4058 9564 4059 9566 4058 9566 4058 9573
      4067 9590 4078 9586 4078 9584 4081 9585
      4096 9579 4094 9539 4058 9538
TIME...MOT...LOC 0707Z 302DEG 36KT 4084 9556 4060 9572 

$$

IAC071-129-NEC131-250730-
/O.CON.KOAX.SV.W.0151.000000T0000Z-210825T0730Z/
Fremont IA-Mills IA-Otoe NE-
209 AM CDT Wed Aug 25 2021

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 230 AM CDT
FOR FREMONT...SOUTHERN MILLS AND NORTHEASTERN OTOE COUNTIES...

At 207 AM CDT, severe thunderstorms were located along a line
extending from 7 miles northeast of Sidney to near Hamburg, moving
southeast at 40 mph.

HAZARD...60 mph wind gusts.

SOURCE...Radar indicated.

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

Locations impacted include...
  Farragut and Shenandoah.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 4058 9564 4059 9566 4058 9566 4058 9573
      4067 9590 4078 9586 4078 9584 4081 9585
      4096 9579 4094 9539 4058 9538
TIME...MOT...LOC 0707Z 302DEG 36KT 4084 9556 4060 9572 

HAIL THREAT...RADAR INDICATED
MAX HAIL SIZE...<.75 IN
WIND THREAT...RADAR INDICATED
MAX WIND GUST...60 MPH

$$

Petersen

813 
WWUS53 KOAX 250730
SVSOAX

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

IAC071-129-NEC131-250739-
/O.EXP.KOAX.SV.W.0151.000000T0000Z-210825T0730Z/
Fremont IA-Mills IA-Otoe NE-
230 AM CDT Wed Aug 25 2021

...THE SEVERE THUNDERSTORM WARNING FOR FREMONT...SOUTHERN MILLS AND
NORTHEASTERN OTOE COUNTIES WILL EXPIRE AT 230 AM CDT...
            
The storms which prompted the warning have weakened below severe
limits, and no longer pose an immediate threat to life or property.
Therefore, the warning will be allowed to expire.

LAT...LON 4058 9564 4059 9566 4058 9566 4058 9573
      4067 9590 4078 9586 4078 9584 4081 9585
      4096 9579 4094 9539 4058 9538
TIME...MOT...LOC 0729Z 302DEG 36KT 4084 9556 4060 9572 

$$

Albright

The office that day

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

Issued	Product	Office	Counties	Lasted
Aug 25, 12:43 AM CDT	Severe Thunderstorm Warning	OAX	Mills, Pottawattamie	47 min
Aug 25, 1:00 AM CDT	Severe Thunderstorm Warning	OAX	Pottawattamie	24 min
Aug 25, 1:16 AM CDT	Severe Thunderstorm Warning	OAX	Fremont, Mills	44 min
Aug 25, 1:25 AM CDT	Severe Thunderstorm Warning	OAX	Mills, Montgomery, Pottawattamie	50 min
Aug 25, 1:58 AM CDT	Severe Thunderstorm Warning	OAX	Mills, Montgomery, Pottawattamie	32 min
Aug 25, 4:07 AM CDT	Heat Advisory	OAX	Fremont, Harrison, Mills, Montgomery, Page, Pottawattamie and 1 more	40 hr
Aug 24, 10:40 PM CDT	Severe Thunderstorm Warning	OAX	Butler, Colfax, Platte	50 min
Aug 24, 11:08 PM CDT	Severe Thunderstorm Warning	OAX	Butler, Colfax	52 min
Aug 24, 11:11 PM CDT	Severe Thunderstorm Warning	OAX	Butler, Saunders	49 min
Aug 24, 11:34 PM CDT	Severe Thunderstorm Warning	OAX	Saunders	26 min
Aug 24, 11:45 PM CDT	Severe Thunderstorm Warning	OAX	Butler, Saunders	14 min
Aug 25, 12:05 AM CDT	Severe Thunderstorm Warning	OAX	Douglas, Saunders	25 min
Aug 25, 12:25 AM CDT	Severe Thunderstorm Warning	OAX	Cass, Douglas, Sarpy, Saunders	50 min
Aug 25, 12:29 AM CDT	Severe Thunderstorm Warning	OAX	Dodge, Douglas, Saunders, Washington	31 min
Aug 25, 4:26 AM CDT	Special Weather Statement	OAX	Richardson	34 min
Aug 25, 2:45 PM CDT	Special Weather Statement	OAX	Knox	30 min
Aug 25, 3:19 PM CDT	Special Weather Statement	OAX	Knox	41 min
Aug 25, 3:58 PM CDT	Special Weather Statement	OAX	Cedar, Knox	47 min
Aug 25, 4:12 PM CDT	Severe Thunderstorm Warning	OAX	Cedar, Knox	48 min

Nearby

Severe Thunderstorm Warnings in Iowa, 2021 Severe Thunderstorm Warnings in Nebraska, 2021 Every 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; local storm reports from the same archive; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.