Alert archive / Iowa / Special Weather Statements in 2021

Special Weather Statement, NWS Quad Cities, IA

August 6, 2021Des Moines County, Iowa

NWS Quad Cities, IA issued this special weather statement at Aug 6, 2021, 4:34 AM CDT for Des Moines County, Iowa. It was in force for 26 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: Aug 6, 2021, 4:34 AM CDT (09:34 UTC)
Expired: Aug 6, 2021, 5:00 AM CDT
In force: 26 min
Issued by: NWS Quad Cities, IA
Hail: 0.50 in
Wind: 40

County Des Moines County, IA

The radar

The Quad Cities radar (KDVN), 105 km from the middle of the area, began a volume at 09:36 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

Davenport, (KDVN), launched 00:00Z, 9.6 hours before the alert went out and 109 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: 2 J/kg
Mixed-layer CIN: -183 J/kg
Mixed-layer LCL: 1356 m above ground
0-6 km bulk shear: 16 kt
0-1 km storm-relative helicity: 157 m²/s²
0-3 km storm-relative helicity: 200 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

The text

As transmitted.

951 
WWUS83 KDVN 060934
SPSDVN

Special Weather Statement
National Weather Service Quad Cities IA/IL
434 AM CDT Fri Aug 6 2021
 
IAZ088-089-099-ILZ025-061000-
Henderson IL-Henry IA-Des Moines IA-Lee IA-
434 AM CDT Fri Aug 6 2021

...A strong thunderstorm will impact portions of west central
Henderson, southeastern Henry, Des Moines and north central Lee
Counties through 500 AM CDT...

At 434 AM CDT, Doppler radar was tracking a strong thunderstorm over
Danville, or 11 miles west of Burlington, moving east at 30 mph.

HAZARD...Winds in excess of 40 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...
  Middletown and Iowa Army Ammunition Plant around 440 AM CDT.
  West Burlington around 450 AM CDT.

Other locations in the path of this storm include Burlington and Gulf
Port.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

If outdoors, consider seeking shelter inside a building. 

Frequent cloud to ground lightning is occurring with this storm.
Lightning can strike 10 miles away from a thunderstorm. Seek a safe
shelter inside a building or vehicle.

&&

LAT...LON 4073 9147 4091 9145 4103 9102 4076 9099
TIME...MOT...LOC 0934Z 248DEG 24KT 4086 9133 

MAX HAIL SIZE...0.50 IN
MAX WIND GUST...40 MPH

$$

Sheets

The office that day

Everything else NWS Quad Cities, IA issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Aug 6, 3:30 AM CDT	Special Weather Statement	DVN	Lee	30 min
Aug 6, 4:26 AM CDT	Special Weather Statement	DVN	Scotland	34 min

Nearby

Special Weather Statements in Iowa, 2021 Every 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.