Alert archive / Iowa / Special Weather Statements in 2021

Special Weather Statement, NWS Des Moines, IA

August 8, 2021Webster County, Iowa

NWS Des Moines, IA issued this special weather statement at Aug 8, 2021, 10:39 PM CDT for Webster County, Iowa. It was in force for 51 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 8, 2021, 10:39 PM CDT (03:39 UTC)
Expired
Aug 8, 2021, 11:30 PM CDT
In force
51 min
Issued by
NWS Des Moines, IA
Hail
0.75 in
Wind
30

County Webster County, IA

The radar

The Des Moines radar (KDMX), 79 km from the middle of the area, began a volume at 03:42 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

TimeReportWhereRemark
Aug 8, 11:23 PM CDTTORNADO3 Ssw Otho, IAPAST WITHIN 50 YARDS OF CHASER. REPORT VIA SOCIAL MEDIA.

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, 3.7 hours before the alert went out and 215 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 2021-08-09Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 1733 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 2021-08-09The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 104 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
1733 J/kg
Mixed-layer CIN
-130 J/kg
Mixed-layer LCL
1356 m above ground
0-6 km bulk shear
36 kt
0-1 km storm-relative helicity
104 m²/s²
0-3 km storm-relative helicity
137 m²/s²
Significant tornado parameter
0.2
Supercell composite
6.0

Open this sounding in Storm Lab

The text

As transmitted.

786 
WWUS83 KDMX 090339
SPSDMX

Special Weather Statement
National Weather Service Des Moines IA
1039 PM CDT Sun Aug 8 2021
 
IAZ035-090430-
Webster IA-
1039 PM CDT Sun Aug 8 2021

...A strong thunderstorm will impact portions of southern Webster
County through 1130 PM CDT...

At 1039 PM CDT, Doppler radar was tracking a strong thunderstorm 8
miles north of Gowrie, or 8 miles southwest of Fort Dodge, moving
southeast at 20 mph.

HAZARD...Penny size hail.

SOURCE...Radar indicated.

IMPACT...Minor damage to outdoor objects is possible.

This strong thunderstorm will be near...
  Gowrie around 1055 PM CDT.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

If outdoors, consider seeking shelter inside a building. 

&&

LAT...LON 4249 9429 4231 9393 4222 9399 4221 9422
      4240 9438
TIME...MOT...LOC 0339Z 311DEG 19KT 4240 9428 

MAX HAIL SIZE...0.75 IN
MAX WIND GUST...<30 MPH

$$

Cogil

The office that day

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

IssuedProductOfficeCountiesLasted
Aug 8, 8:36 PM CDTTornado WarningDMXPocahontas24 min
Aug 8, 9:02 PM CDTTornado WarningDMXCalhoun, Pocahontas31 min
Aug 8, 11:00 PM CDTTornado WarningDMXWebster30 min
Aug 8, 11:30 PM CDTTornado Warning Tornado observedDMXWebster30 min
Aug 8, 11:52 PM CDTTornado WarningDMXBoone, Webster38 min
Aug 9, 12:23 AM CDTTornado WarningDMXButler, Franklin20 min
Aug 9, 12:29 AM CDTSevere Thunderstorm WarningDMXBoone, Hamilton, Webster46 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; local storm reports from the same archive; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.