Alert archive / Iowa / Special Weather Statements in 2020
Special Weather Statement, NWS Des Moines, IA
NWS Des Moines, IA issued this special weather statement at Aug 6, 2020, 3:21 PM CDT for Boone County, Iowa. It was in force for 24 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, 2020, 3:21 PM CDT (20:21 UTC)
- Expired
- Aug 6, 2020, 3:45 PM CDT
- In force
- 24 min
- Issued by
- NWS Des Moines, IA
County Boone County, IA
The radar
The Des Moines radar (KDMX), 18 km from the middle of the area, began a volume at 20:21 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 12:00Z, 8.4 hours before the alert went out and 219 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.
- Mixed-layer CAPE
- 284 J/kg
- Mixed-layer CIN
- -289 J/kg
- Mixed-layer LCL
- 1016 m above ground
- 0-6 km bulk shear
- 25 kt
- 0-1 km storm-relative helicity
- 161 m²/s²
- 0-3 km storm-relative helicity
- 268 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.5
The text
As transmitted.
519 WWUS83 KDMX 062021 SPSDMX Special Weather Statement National Weather Service Des Moines IA 321 PM CDT Thu Aug 6 2020 IAZ047-048-059-060-062045- Boone IA-Story IA-Polk IA-Dallas IA- 321 PM CDT Thu Aug 6 2020 ...Heavy rain and small hail possible... At 321 PM CDT, Doppler radar was tracking a strong thunderstorm over Madrid, or 12 miles south of Boone, moving southeast at 20 mph. Penny size hail and winds in excess of 30 mph will be possible with this storm. Rainfall amounts up to two inches may be common with this storm. Locations impacted include... Johnston, Polk City, Huxley, Madrid, Slater, Granger, Woodward, Big Creek Lake, Saylorville Lake, Sheldahl, Luther, Big Creek State Park and Ledges State Park. PRECAUTIONARY/PREPAREDNESS ACTIONS... Torrential rainfall is also occurring with this storm. 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. && LAT...LON 4187 9399 4199 9392 4190 9357 4171 9372 TIME...MOT...LOC 2021Z 298DEG 17KT 4189 9380 $$ Ansorge
The office that day
Everything else NWS Des Moines, IA issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Aug 6, 10:57 AM CDT | Special Weather Statement | DMX | Guthrie | 48 min |
| Aug 6, 11:00 AM CDT | Special Weather Statement | DMX | Dallas | 45 min |
| Aug 6, 11:11 AM CDT | Severe Thunderstorm Warning | DMX | Carroll, Greene, Guthrie | 32 min |
| Aug 6, 12:00 PM CDT | Special Weather Statement | DMX | Dallas | 45 min |
| Aug 6, 1:01 PM CDT | Special Weather Statement | DMX | Madison | 29 min |
| Aug 6, 2:05 PM CDT | Special Weather Statement | DMX | Greene | 25 min |
| Aug 6, 3:35 PM CDT | Severe Thunderstorm Warning | DMX | Boone, Dallas, Polk, Story | 40 min |
| Aug 6, 4:15 PM CDT | Special Weather Statement | DMX | Polk | 45 min |
Nearby
Special Weather Statements in Iowa, 2020Every special weather statement in 2020
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.