Alert archive / Iowa / Special Weather Statements in 2021

Special Weather Statement, NWS Des Moines, IA

September 14, 2021Hamilton County, Iowa

NWS Des Moines, IA issued this special weather statement at Sep 14, 2021, 1:08 AM CDT for Hamilton County, Iowa. It was in force for 37 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
Sep 14, 2021, 1:08 AM CDT (06:08 UTC)
Expired
Sep 14, 2021, 1:45 AM CDT
In force
37 min
Issued by
NWS Des Moines, IA
Hail
0.88 in
Wind
40

County Hamilton County, IA

The radar

The Des Moines radar (KDMX), 76 km from the middle of the area, began a volume at 06:11 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 nearest sounding before it

Omaha, NE (KOAX), launched 00:00Z, 6.1 hours before the alert went out and 258 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 2021-09-14Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 1361 joules per kilogram.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°0°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Omaha, NE at 00:00Z on 2021-09-14The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 98 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
1361 J/kg
Mixed-layer CIN
-168 J/kg
Mixed-layer LCL
1731 m above ground
0-6 km bulk shear
42 kt
0-1 km storm-relative helicity
98 m²/s²
0-3 km storm-relative helicity
213 m²/s²
Significant tornado parameter
0.1
Supercell composite
6.1

Open this sounding in Storm Lab

The text

As transmitted.

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What forecasters said that day

The local office's own words before this special weather statement went out, as it sent them, from the Iowa Environmental Mesonet's archive of National Weather Service text.

NWS Des Moines, IA wrote its last area forecast discussion before this special weather statement went out at Sep 13, 11:57 PM CDT, 1 hour 11 minutes earlier.

Area forecast discussion, Sep 13, 11:57 PM CDT, 1 hour 11 minutes before
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Hazardous weather outlook, Sep 13, 2:46 PM CDT, 10 hours 22 minutes before
Hazardous Weather Outlook
National Weather Service Des Moines IA
246 PM CDT Mon Sep 13 2021

IAZ057>062-070>075-081>086-092>097-141100-
Audubon-Guthrie-Dallas-Polk-Jasper-Poweshiek-Cass-Adair-Madison-
Warren-Marion-Mahaska-Adams-Union-Clarke-Lucas-Monroe-Wapello-
Taylor-Ringgold-Decatur-Wayne-Appanoose-Davis-
246 PM CDT Mon Sep 13 2021

This Hazardous Weather Outlook is for portions of central Iowa.

.DAY ONE...This afternoon and tonight

No hazardous weather is expected at this time.

.DAYS TWO THROUGH SEVEN...Tuesday through Sunday

There is a chance of thunderstorms on Tuesday, mainly south of
Interstate 80 in the afternoon and evening. Additional
thunderstorm chances are forecast around Thursday night and
Friday. No severe weather is expected at this time.

.SPOTTER INFORMATION STATEMENT...

Spotter activation is not anticipated.

IAZ004>007-015>017-023>028-033>039-044>050-141100-
Emmet-Kossuth-Winnebago-Worth-Palo Alto-Hancock-Cerro Gordo-
Pocahontas-Humboldt-Wright-Franklin-Butler-Bremer-Sac-Calhoun-
Webster-Hamilton-Hardin-Grundy-Black Hawk-Crawford-Carroll-Greene-
Boone-Story-Marshall-Tama-
246 PM CDT Mon Sep 13 2021

This Hazardous Weather Outlook is for portions of central Iowa.

.DAY ONE...This afternoon and tonight

Widely scattered showers and thunderstorms are expected across
mainly far northern Iowa this evening and tonight. A few strong
to severe storms may produce large hail, and an isolated tornado
remains possible near the Minnesota border.

.DAYS TWO THROUGH SEVEN...Tuesday through Sunday

Thunderstorm chances return to the forecast from Thursday through
Friday. The threat of severe weather appears low at this time.

.SPOTTER INFORMATION STATEMENT...

Spotter activation is not anticipated.

Lee

In the hours before

Special weather statement, Sep 13, 10:02 PM CDT, 3 hours 6 minutes before
Special Weather Statement
National Weather Service Des Moines IA
1002 PM CDT Mon Sep 13 2021

IAZ044-140330-
Crawford IA-
1002 PM CDT Mon Sep 13 2021

...A strong thunderstorm will impact portions of central Crawford
County through 1030 PM CDT...

At 1001 PM CDT, Doppler radar was tracking a strong thunderstorm 7
miles east of Ute, or 11 miles west of Denison, moving east at 40
mph.

HAZARD...Winds in excess of 30 mph and half inch hail.

SOURCE...Radar indicated.

IMPACT...Gusty winds could knock down tree limbs and blow around
         unsecured objects. Minor damage to outdoor objects is
         possible.

This strong thunderstorm will be near...
  Denison around 1020 PM CDT.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

If outdoors, consider seeking shelter inside a building.

&&

LAT...LON 4198 9567 4211 9567 4219 9523 4201 9518
TIME...MOT...LOC 0301Z 257DEG 36KT 4205 9557

MAX HAIL SIZE...0.50 IN
MAX WIND GUST...30 MPH

Hagenhoff
Special weather statement, Sep 14, 1:08 AM CDT, 0 minutes before
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The office that day

Everything else NWS Des Moines, IA issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Sep 13, 10:02 PM CDTSpecial Weather StatementDMXCrawford28 min
Sep 13, 10:18 PM CDTSevere Thunderstorm WarningDMXCarroll, Crawford27 min

Nearby

Special Weather Statements in Iowa, 2021Every special weather statement 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.