Alert archive / Iowa / Tornado Warnings in 2016

Tornado Warning 11, NWS Des Moines, IA

September 21, 2016Bremer County, Butler County, Iowa

NWS Des Moines, IA issued this tornado warning at Sep 21, 2016, 6:59 PM CDT for Bremer County, Butler County, Iowa. It was in force for 46 min. 2 reports 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 21, 2016, 6:59 PM CDT (23:59 UTC)
Expired: Sep 21, 2016, 7:45 PM CDT
In force: 46 min
Issued by: NWS Des Moines, IA
Area: Storm-based polygon
Tornado: Radar indicated
Hail: 1.0 in

Counties Bremer County, IA, Butler County, IA

The radar

The Des Moines radar (KDMX), 152 km from the middle of the area, began a volume at 00:01 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 21, 7:11 PM CDT	HAIL 1	Greene, IA	REPORT VIA SOCIAL MEDIA.
Sep 21, 7:49 PM CDT	HAIL 1	Greene, IA	.

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 12:00Z, 12.0 hours before the alert went out and 222 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: 3354 J/kg
Mixed-layer CIN: -30 J/kg
Mixed-layer LCL: 946 m above ground
0-6 km bulk shear: 22 kt
0-1 km storm-relative helicity: 72 m²/s²
0-3 km storm-relative helicity: 84 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 3.4

Open this sounding in Storm Lab

The text

As transmitted.

498 
WFUS53 KDMX 212359
TORDMX
IAC017-023-220045-
/O.NEW.KDMX.TO.W.0011.160921T2359Z-160922T0045Z/

BULLETIN - EAS ACTIVATION REQUESTED
TORNADO WARNING
NATIONAL WEATHER SERVICE DES MOINES IA
659 PM CDT WED SEP 21 2016

THE NATIONAL WEATHER SERVICE IN DES MOINES  HAS ISSUED A

* TORNADO WARNING FOR...
  NORTHEASTERN BUTLER COUNTY IN NORTH CENTRAL IOWA...
  NORTHWESTERN BREMER COUNTY IN NORTHEASTERN IOWA...

* UNTIL 745 PM CDT.

* AT 659 PM CDT...A SEVERE THUNDERSTORM CAPABLE OF PRODUCING A
  TORNADO WAS LOCATED OVER GREENE...OR 8 MILES NORTH OF ALLISON...
  MOVING EAST AT 15 MPH.

  HAZARD...TORNADO AND QUARTER SIZE HAIL. 

  SOURCE...RADAR INDICATED ROTATION. 

  IMPACT...FLYING DEBRIS WILL BE DANGEROUS TO THOSE CAUGHT WITHOUT 
           SHELTER. MOBILE HOMES WILL BE DAMAGED OR DESTROYED. 
           DAMAGE TO ROOFS...WINDOWS...AND VEHICLES WILL OCCUR.  
           TREE DAMAGE IS LIKELY. 

* THIS TORNADIC THUNDERSTORM WILL REMAIN OVER MAINLY RURAL AREAS OF
  NORTHEASTERN BUTLER AND NORTHWESTERN BREMER COUNTIES...INCLUDING
  THE FOLLOWING LOCATIONS: PLAINFIELD.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

TAKE COVER NOW! MOVE TO A BASEMENT OR AN INTERIOR ROOM ON THE LOWEST
FLOOR OF A STURDY BUILDING. AVOID WINDOWS. IF YOU ARE OUTDOORS...IN A
MOBILE HOME...OR IN A VEHICLE...MOVE TO THE CLOSEST SUBSTANTIAL
SHELTER AND PROTECT YOURSELF FROM FLYING DEBRIS.

HEAVY RAINFALL MAY HIDE THIS TORNADO. DO NOT WAIT TO SEE OR HEAR THE
TORNADO. TAKE COVER NOW!

TORNADOES ARE EXTREMELY DIFFICULT TO SEE AND CONFIRM AT NIGHT. DO NOT
WAIT TO SEE OR HEAR THE TORNADO. TAKE COVER NOW!

&&

LAT...LON 4276 9246 4284 9291 4291 9291 4291 9245
TIME...MOT...LOC 2359Z 277DEG 14KT 4288 9283 

TORNADO...RADAR INDICATED
HAIL...1.00IN

$$

REV

The office that day

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

Issued	Product	Office	Counties	Lasted
Sep 21, 3:26 PM CDT	Special Weather Statement	DMX	Cerro Gordo	49 min
Sep 21, 3:32 PM CDT	Severe Thunderstorm Warning	DMX	Cerro Gordo	43 min
Sep 21, 4:23 PM CDT	Severe Thunderstorm Warning	DMX	Cerro Gordo	37 min
Sep 21, 4:50 PM CDT	Flash Flood Warning	DMX	Cerro Gordo	6 hr
Sep 21, 4:57 PM CDT	Severe Thunderstorm Warning	DMX	Cerro Gordo	31 min
Sep 21, 5:13 PM CDT	Severe Thunderstorm Warning	DMX	Butler, Franklin	47 min
Sep 21, 5:19 PM CDT	Tornado Warning	DMX	Butler	56 min
Sep 21, 5:45 PM CDT	Severe Thunderstorm Warning	DMX	Cerro Gordo, Worth	45 min
Sep 21, 6:17 PM CDT	Tornado Warning	DMX	Butler	43 min
Sep 21, 6:33 PM CDT	Flash Flood Warning	DMX	Cerro Gordo, Worth	6 hr
Sep 21, 6:44 PM CDT	Severe Thunderstorm Warning	DMX	Cerro Gordo	46 min
Sep 21, 6:58 PM CDT	Flash Flood Warning	DMX	Butler	12 hr

Nearby

Tornado Warnings in Iowa, 2016 Every tornado warning in 2016 Tornadoes in 2016

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.