Alert archive / Iowa / Severe Thunderstorm Warnings in 2021

Severe Thunderstorm Warning 87, NWS Omaha, NE

July 9, 2021Harrison County, Monona County, Iowa

NWS Omaha, NE issued this severe thunderstorm warning at Jul 9, 2021, 1:14 AM CDT for Harrison County, Monona County, Iowa. It was in force for 31 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 9, 2021, 1:14 AM CDT (06:14 UTC)
Expired
Jul 9, 2021, 1:45 AM CDT
In force
31 min
Issued by
NWS Omaha, NE
Area
Storm-based polygon
Hail
1.5 in
Wind
50.0 mph

Counties Harrison County, IA, Monona County, IA

The radar

The Omaha radar (KOAX), 81 km from the middle of the area, began a volume at 06:17 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, 6.2 hours before the alert went out and 81 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 2021-07-09Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 155 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 2021-07-09The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 200 square meters per square second.19395878Sfc1 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
155 J/kg
Mixed-layer CIN
-474 J/kg
Mixed-layer LCL
1131 m above ground
0-6 km bulk shear
54 kt
0-1 km storm-relative helicity
200 m²/s²
0-3 km storm-relative helicity
406 m²/s²
Significant tornado parameter
0.0
Supercell composite
-0.0

Open this sounding in Storm Lab

The text

As transmitted.

774 
WUUS53 KOAX 090614
SVROAX
IAC085-133-090645-
/O.NEW.KOAX.SV.W.0087.210709T0614Z-210709T0645Z/

BULLETIN - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Warning
National Weather Service Omaha/Valley Nebraska
114 AM CDT Fri Jul 9 2021

The National Weather Service in Omaha has issued a

* Severe Thunderstorm Warning for...
  Monona County in west central Iowa...
  North central Harrison County in southwestern Iowa...

* Until 145 AM CDT.

* At 113 AM CDT, a severe thunderstorm was located 5 miles east of
  Onawa, or 32 miles west of Denison, moving east at 40 mph.

  HAZARD...Ping pong ball size hail.

  SOURCE...Radar indicated.

  IMPACT...People and animals outdoors will be injured. Expect 
           damage to roofs, siding, windows, and vehicles.

* This severe thunderstorm will be near...
  Moorhead around 125 AM CDT.
  Ute around 130 AM CDT.

This includes Interstate 29 between mile markers 105 and 109.
 
PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 4179 9569 4193 9614 4196 9613 4199 9615
      4221 9602 4215 9567 4186 9567
TIME...MOT...LOC 0613Z 291DEG 41KT 4204 9599 

HAIL...1.50IN
WIND...<50MPH
 
$$

Fajman
3 follow-up statements
167 
WWUS53 KOAX 090625
SVSOAX

Severe Weather Statement
National Weather Service Omaha/Valley Nebraska
125 AM CDT Fri Jul 9 2021

IAC085-133-090645-
/O.CON.KOAX.SV.W.0087.000000T0000Z-210709T0645Z/
Monona IA-Harrison IA-
125 AM CDT Fri Jul 9 2021

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 145 AM CDT
FOR EASTERN MONONA AND NORTH CENTRAL HARRISON COUNTIES...

At 125 AM CDT, a severe thunderstorm was located near Moorhead, or 23
miles west of Denison, moving east at 45 mph.

HAZARD...Ping pong ball size hail.

SOURCE...Radar indicated.

IMPACT...People and animals outdoors will be injured. Expect damage 
         to roofs, siding, windows, and vehicles.

This severe storm will be near...
  Ute around 130 AM CDT.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 4179 9569 4190 9598 4215 9606 4221 9602
      4215 9567 4186 9567
TIME...MOT...LOC 0625Z 291DEG 41KT 4199 9582 

HAIL...1.50IN
WIND...<50MPH
 
$$

Fajman
028 
WWUS53 KOAX 090638
SVSOAX

Severe Weather Statement
National Weather Service Omaha/Valley Nebraska
138 AM CDT Fri Jul 9 2021

IAC085-133-090645-
/O.CON.KOAX.SV.W.0087.000000T0000Z-210709T0645Z/
Monona IA-Harrison IA-
138 AM CDT Fri Jul 9 2021

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 145 AM CDT
FOR SOUTHEASTERN MONONA AND NORTH CENTRAL HARRISON COUNTIES...

At 138 AM CDT, a severe thunderstorm was located 5 miles north of
Dunlap, or 15 miles west of Denison, moving east at 45 mph.

HAZARD...Quarter size hail.

SOURCE...Radar indicated.

IMPACT...Damage to vehicles is expected.

This severe thunderstorm will remain over mainly rural areas of
southeastern Monona and north central Harrison Counties, including
the following locations... Soldier.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 4182 9568 4189 9587 4203 9581 4199 9567
      4186 9567
TIME...MOT...LOC 0638Z 291DEG 41KT 4193 9563 

HAIL...1.00IN
WIND...<50MPH
 
$$

Fajman
082 
WWUS53 KOAX 090642
SVSOAX

Severe Weather Statement
National Weather Service Omaha/Valley Nebraska
142 AM CDT Fri Jul 9 2021

IAC085-133-090652-
/O.EXP.KOAX.SV.W.0087.000000T0000Z-210709T0645Z/
Monona IA-Harrison IA-
142 AM CDT Fri Jul 9 2021

...THE SEVERE THUNDERSTORM WARNING FOR SOUTHEASTERN MONONA AND NORTH
CENTRAL HARRISON COUNTIES WILL EXPIRE AT 145 AM CDT...
        
The storm which prompted the warning has weakened below severe
limits, and has exited the warned area. Therefore, the warning will
be allowed to expire.

LAT...LON 4182 9568 4189 9587 4203 9581 4199 9567
      4186 9567
TIME...MOT...LOC 0642Z 291DEG 41KT 4193 9563 

$$

Fajman

The office that day

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

IssuedProductOfficeCountiesLasted
Jul 9, 2:29 AM CDTSpecial Weather StatementOAXShelby31 min
Jul 9, 6:48 AM CDTSpecial Weather StatementOAXShelby27 min

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.