Alert archive / Iowa / Tornado Warnings in 2021

Tornado Warning 8, NWS Omaha, NE

July 30, 2021Page County, Iowa

NWS Omaha, NE issued this tornado warning at Jul 30, 2021, 10:12 PM CDT for Page County, Iowa. It was in force for 18 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
Jul 30, 2021, 10:12 PM CDT (03:12 UTC)
Expired
Jul 30, 2021, 10:30 PM CDT
In force
18 min
Issued by
NWS Omaha, NE
Area
Storm-based polygon
Tornado
Radar indicated
Hail
0.75 in

County Page County, IA

The radar

The Omaha radar (KOAX), 137 km from the middle of the area, began a volume at 03:11 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 watch it was issued in

The SPC watch in force over the same counties when this warning went out.

IssuedProductOfficeLasted
Jul 30, 8:47 PM CDTSevere Thunderstorm WatchSPC5 hr

The nearest sounding before it

Omaha, NE (KOAX), launched 00:00Z, 3.2 hours before the alert went out and 137 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 2021-07-31Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 2669 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 2021-07-31The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 52 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
2669 J/kg
Mixed-layer CIN
-3 J/kg
Mixed-layer LCL
967 m above ground
0-6 km bulk shear
40 kt
0-1 km storm-relative helicity
52 m²/s²
0-3 km storm-relative helicity
279 m²/s²
Significant tornado parameter
3.4
Supercell composite
19.5

Open this sounding in Storm Lab

The text

As transmitted.

144 
WFUS53 KOAX 310312
TOROAX
IAC145-310330-
/O.NEW.KOAX.TO.W.0008.210731T0312Z-210731T0330Z/

BULLETIN - EAS ACTIVATION REQUESTED
Tornado Warning
National Weather Service Omaha/Valley Nebraska
1012 PM CDT Fri Jul 30 2021

The National Weather Service in Omaha has issued a

* Tornado Warning for...
  South central Page County in southwestern Iowa...

* Until 1030 PM CDT.
    
* At 1012 PM CDT, a severe thunderstorm capable of producing a
  tornado was located over Braddyville, or 18 miles west of Bedford,
  moving south at 30 mph.

  HAZARD...Tornado.

  SOURCE...Radar indicated rotation.

  IMPACT...Flying debris will be dangerous to those caught without 
           shelter. Mobile homes will be damaged or destroyed. 
           Damage to roofs, windows, and vehicles will occur.  Tree 
           damage is likely.

* This dangerous storm will be near...
  Braddyville around 1015 PM CDT.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

TAKE COVER NOW! Move to a basement or an interior room on the lowest
floor of a sturdy building. Avoid windows. If you are outdoors, in a
mobile home, or in a vehicle, move to the closest substantial shelter
and protect yourself from flying debris.

&&

LAT...LON 4057 9498 4058 9510 4058 9511 4064 9512
      4066 9505 4058 9497
TIME...MOT...LOC 0312Z 338DEG 24KT 4061 9506 

TORNADO...RADAR INDICATED
HAIL...<.75IN

$$

Petersen
2 follow-up statements
844 
WWUS53 KOAX 310322
SVSOAX

Severe Weather Statement
National Weather Service Omaha/Valley Nebraska
1022 PM CDT Fri Jul 30 2021

IAC145-310330-
/O.CON.KOAX.TO.W.0008.000000T0000Z-210731T0330Z/
Page IA-
1022 PM CDT Fri Jul 30 2021

...A TORNADO WARNING REMAINS IN EFFECT UNTIL 1030 PM CDT FOR SOUTH
CENTRAL PAGE COUNTY...
    
At 1022 PM CDT, a severe thunderstorm capable of producing a tornado
was located over Braddyville, or 16 miles northwest of Maryville,
moving south at 30 mph.

HAZARD...Tornado.

SOURCE...Radar indicated rotation.

IMPACT...Flying debris will be dangerous to those caught without 
         shelter. Mobile homes will be damaged or destroyed. Damage 
         to roofs, windows, and vehicles will occur.  Tree damage is 
         likely.

This tornadic thunderstorm will remain over mainly rural areas of
south central Page County, including the following locations...
Braddyville.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

TAKE COVER NOW! Move to a basement or an interior room on the lowest
floor of a sturdy building. Avoid windows. If you are outdoors, in a
mobile home, or in a vehicle, move to the closest substantial shelter
and protect yourself from flying debris.

&&

LAT...LON 4058 9508 4061 9509 4062 9501 4058 9497
      4057 9498
TIME...MOT...LOC 0322Z 338DEG 24KT 4055 9503 

TORNADO...RADAR INDICATED
HAIL...<.75IN

$$

Petersen
429 
WWUS53 KOAX 310326
SVSOAX

Severe Weather Statement
National Weather Service Omaha/Valley Nebraska
1026 PM CDT Fri Jul 30 2021

IAC145-310335-
/O.EXP.KOAX.TO.W.0008.000000T0000Z-210731T0330Z/
Page IA-
1026 PM CDT Fri Jul 30 2021

...THE TORNADO WARNING FOR SOUTH CENTRAL PAGE COUNTY WILL EXPIRE AT
1030 PM CDT...
        
The storm which prompted the warning has moved out of the area.
Therefore, the warning will be allowed to expire.

A Severe Thunderstorm Watch remains in effect until 200 AM CDT for
southwestern Iowa.

LAT...LON 4058 9508 4061 9509 4062 9501 4058 9497
      4057 9498
TIME...MOT...LOC 0325Z 338DEG 24KT 4053 9502 

$$

Petersen

The office that day

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

IssuedProductOfficeCountiesLasted
Jul 30, 8:06 PM CDTSpecial Weather StatementOAXPottawattamie24 min
Jul 30, 8:12 PM CDTSevere Thunderstorm WarningOAXPottawattamie, Shelby33 min
Jul 30, 8:42 PM CDTSevere Thunderstorm WarningOAXMills, Montgomery, Page, Pottawattamie33 min
Jul 30, 9:03 PM CDTSevere Thunderstorm WarningOAXFremont, Mills, Page42 min
Jul 30, 9:13 PM CDTSevere Thunderstorm WarningOAXMontgomery, Page32 min
Jul 30, 9:39 PM CDTSevere Thunderstorm WarningOAXFremont, Page51 min
Jul 31, 2:14 AM CDTSpecial Weather StatementOAXPottawattamie76 min

Nearby

Tornado Warnings in Iowa, 2021Every tornado warning in 2021Tornadoes 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.