Alert archive / Iowa / Severe Thunderstorm Warnings in 2012

Severe Thunderstorm Warning 83, NWS Quad Cities, IA

September 7, 2012Louisa County, Iowa; Mercer County, Illinois

NWS Quad Cities, IA issued this severe thunderstorm warning at Sep 7, 2012, 3:17 AM CDT for Louisa County, Iowa; Mercer County, Illinois. It was in force for 13 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: Sep 7, 2012, 3:17 AM CDT (08:17 UTC)
Expired: Sep 7, 2012, 3:30 AM CDT
In force: 13 min
Issued by: NWS Quad Cities, IA
Area: Storm-based polygon
Hail: 1.0 in
Wind: 58.0 mph

Counties Louisa County, IA, Mercer County, IL

The radar

The Quad Cities radar (KDVN), 58 km from the middle of the area, began a volume at 08:21 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.

What was reported inside it

Time	Report	Where	Remark
Sep 7, 3:28 AM CDT	HAIL 0.88	Nne Grandview, IA	COVERED THE GROUND.

Local storm reports filed while the alert was in force, from inside its polygon or its counties.

The nearest sounding before it

Davenport, (KDVN), launched 00:00Z, 8.3 hours before the alert went out and 64 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: -633 J/kg
Mixed-layer LCL: 1997 m above ground
0-6 km bulk shear: 36 kt
0-1 km storm-relative helicity: -4 m²/s²
0-3 km storm-relative helicity: 66 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

The text

As transmitted, in the capitals the NWS used until 2016.

871 
WUUS53 KDVN 070817
SVRDVN
IAC115-ILC131-070830-
/O.NEW.KDVN.SV.W.0083.120907T0817Z-120907T0830Z/

BULLETIN - EAS ACTIVATION REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE QUAD CITIES IA IL
317 AM CDT FRI SEP 7 2012

THE NATIONAL WEATHER SERVICE IN THE QUAD CITIES HAS ISSUED A

* SEVERE THUNDERSTORM WARNING FOR...
  NORTHWESTERN MERCER COUNTY IN NORTHWEST ILLINOIS...
  CENTRAL LOUISA COUNTY IN SOUTHEAST IOWA...

* UNTIL 330 AM CDT.

* AT 316 AM CDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A
  SEVERE THUNDERSTORM CAPABLE OF PRODUCING QUARTER SIZE HAIL.  THIS
  STORM WAS LOCATED APPROXIMATELY NEAR GRANDVIEW...OR 6 MILES NORTH
  OF WAPELLO...AND MOVING EAST AT 30 MPH.

* THE SEVERE THUNDERSTORM WILL OTHERWISE REMAIN OVER MAINLY RURAL
  AREAS OF THE INDICATED COUNTIES.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

THIS IS A DANGEROUS STORM. MOVE IMMEDIATELY INDOORS AND STAY AWAY
FROM WINDOWS.

&&

LAT...LON 4132 9103 4123 9100 4123 9125 4128 9127
TIME...MOT...LOC 0817Z 263DEG 27KT 4126 9119
WIND...HAIL <58MPH 1.00IN

$$

08

1 follow-up statement

618 
WWUS53 KDVN 070827
SVSDVN

SEVERE WEATHER STATEMENT
NATIONAL WEATHER SERVICE QUAD CITIES IA IL
327 AM CDT FRI SEP 7 2012

IAC115-ILC131-070837-
/O.EXP.KDVN.SV.W.0083.000000T0000Z-120907T0830Z/
LOUISA IA-MERCER IL-
327 AM CDT FRI SEP 7 2012

...THE SEVERE THUNDERSTORM WARNING FOR NORTHWESTERN MERCER AND
CENTRAL LOUISA COUNTIES WILL EXPIRE AT 330 AM CDT...

THE THUNDERSTORM THAT WAS CAPABLE OF PRODUCING SEVERE WEATHER HAS
WEAKENED. THEREFORE THE SEVERE THUNDERSTORM WARNING HAS BEEN ALLOWED
TO EXPIRE.

LAT...LON 4132 9103 4123 9100 4123 9125 4128 9127
TIME...MOT...LOC 0827Z 263DEG 27KT 4127 9109

$$

08

The office that day

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

Issued	Product	Office	Counties	Lasted
Sep 7, 1:06 AM CDT	Special Weather Statement	DVN	Johnson	54 min
Sep 7, 1:51 AM CDT	Severe Thunderstorm Warning	DVN	Cedar, Johnson, Muscatine	39 min
Sep 7, 2:35 AM CDT	Special Weather Statement	DVN	Cedar, Johnson, Scott	85 min
Sep 7, 2:47 AM CDT	Special Weather Statement	DVN	Benton, Iowa	88 min
Sep 7, 2:54 AM CDT	Special Weather Statement	DVN	Louisa	81 min
Sep 7, 3:56 AM CDT	Severe Thunderstorm Warning	DVN	Iowa, Johnson, Keokuk, Washington	34 min
Sep 7, 4:13 AM CDT	Severe Thunderstorm Warning	DVN	Keokuk	32 min
Sep 7, 5:20 AM CDT	Severe Thunderstorm Warning	DVN	Louisa, Muscatine	40 min
Sep 7, 4:22 AM CDT	Special Weather Statement	DVN	Henry, Mercer, Rock Island	83 min
Sep 7, 4:29 AM CDT	Severe Thunderstorm Warning	DVN	Henderson, Warren	31 min

Nearby

Severe Thunderstorm Warnings in Iowa, 2012 Severe Thunderstorm Warnings in Illinois, 2012 Every severe thunderstorm warning in 2012

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.