Alert archive / Iowa / Special Weather Statements in 2018

Special Weather Statement, NWS Quad Cities, IA

August 7, 2018Van Buren County, Iowa

NWS Quad Cities, IA issued this special weather statement at Aug 7, 2018, 5:21 PM CDT for Van Buren County, Iowa. It was in force for 39 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 7, 2018, 5:21 PM CDT (22:21 UTC)
Expired
Aug 7, 2018, 6:00 PM CDT
In force
39 min
Issued by
NWS Quad Cities, IA

County Van Buren County, IA

The radar

The Quad Cities radar (KDVN), 149 km from the middle of the area, began a volume at 22:25 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 12:00Z, 10.4 hours before the alert went out and 155 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, Davenport, at 12:00Z on 2018-08-07Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 600 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, Davenport, at 12:00Z on 2018-08-07The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 25 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
600 J/kg
Mixed-layer CIN
-36 J/kg
Mixed-layer LCL
632 m above ground
0-6 km bulk shear
31 kt
0-1 km storm-relative helicity
25 m²/s²
0-3 km storm-relative helicity
80 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.3

Open this sounding in Storm Lab

The text

As transmitted.

275 
WWUS83 KDVN 072221
SPSDVN

Special Weather Statement
National Weather Service Quad Cities IA/IL
521 PM CDT TUE AUG 7 2018

IAC101-177-072300-
Van Buren-Jefferson-
521 PM CDT TUE AUG 7 2018

...A STRONG THUNDERSTORM WILL AFFECT WESTERN VAN BUREN AND
SOUTHWESTERN JEFFERSON COUNTIES UNTIL 600 PM CDT...

At 521 PM CDT, a strong thunderstorm was located near Douds, or 13
miles southwest of Fairfield, moving southeast at 25 mph.

Winds in excess of 40 mph and dime size hail are possible with this
storm.

Locations impacted include...
Keosauqua, Birmingham, Libertyville, Stockport, Douds, Leando, Van
Buren County Fairgrounds, Keosauqua Airport, Mount Zion, Selma,
Lebanon, Collett, Lake Sugema Campground, Lacey Keosauqua State Park
and Kilbourn.

Torrential rainfall is also occurring with this storm, and may cause
localized flooding. Do not drive your vehicle through flooded
roadways.

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.

Persons in campgrounds should consider seeking sturdy shelter until
this storm passes.

LAT...LON 4099 9218 4091 9181 4066 9196 4077 9218
TIME...MOT...LOC 2221Z 294DEG 17KT 4089 9217 

$$

12

The office that day

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

IssuedProductOfficeCountiesLasted
Aug 6, 10:00 PM CDTSpecial Weather StatementDVNHenry, Jefferson, Van Buren45 min
Aug 6, 10:11 PM CDTSevere Thunderstorm WarningDVNHenry, Jefferson37 min
Aug 7, 1:28 PM CDTSpecial Weather StatementDVNJones17 min
Aug 7, 5:13 PM CDTSpecial Weather StatementDVNBenton32 min
Aug 7, 5:51 PM CDTSpecial Weather StatementDVNBenton, Linn54 min
Aug 7, 12:59 PM CDTSpecial Weather StatementDVNWhiteside31 min
Aug 6, 7:08 PM CDTSpecial Weather StatementDVNScotland22 min

Nearby

Special Weather Statements in Iowa, 2018Every special weather statement in 2018

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.