Alert archive / Iowa / Severe Thunderstorm Warnings in 2017

Severe Thunderstorm Warning 2, NWS Des Moines, IA

February 28, 2017Mahaska County, Marion County, Iowa

NWS Des Moines, IA issued this severe thunderstorm warning at Feb 28, 2017, 4:01 PM CST for Mahaska County, Marion County, Iowa. It was in force for 44 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: Feb 28, 2017, 4:01 PM CST (22:01 UTC)
Expired: Feb 28, 2017, 4:45 PM CST
In force: 44 min
Issued by: NWS Des Moines, IA
Area: Storm-based polygon
Hail: 1.0 in
Wind: 50.0 mph

Counties Mahaska County, IA, Marion County, IA

The radar

The Des Moines radar (KDMX), 89 km from the middle of the area, began a volume at 22:05 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
Feb 28, 4:36 PM CST	HAIL 1	1 N Oskaloosa, IA	TRAINED SPOTTER REPORTED LOTS OF SMALL HAIL WITH A FEW MEASURED 1 INCH HAIL STONES MIXED IN.
Feb 28, 4:38 PM CST	HAIL 1	2 Nw Oskaloosa, IA	TRAINED SPOTTER REPORTED 1 INCH HAIL.

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, 10.0 hours before the alert went out and 203 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: 30 J/kg
Mixed-layer CIN: -241 J/kg
Mixed-layer LCL: 771 m above ground
0-6 km bulk shear: 80 kt
0-1 km storm-relative helicity: 223 m²/s²
0-3 km storm-relative helicity: 294 m²/s²
Significant tornado parameter: 0.0
Supercell composite: -0.0

Open this sounding in Storm Lab

The text

As transmitted.

540 
WUUS53 KDMX 282201
SVRDMX
IAC123-125-282245-
/O.NEW.KDMX.SV.W.0002.170228T2201Z-170228T2245Z/

BULLETIN - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Warning
National Weather Service Des Moines IA
401 PM CST TUE FEB 28 2017

The National Weather Service in Des Moines  has issued a

* Severe Thunderstorm Warning for...
  Southeastern Marion County in south central Iowa...
  Western Mahaska County in south central Iowa...

* Until 445 PM CST.

* At 401 PM CST, a severe thunderstorm was located near
  Melcher-Dallas, or 7 miles south of Knoxville, moving northeast at
  40 mph.

  HAZARD...Quarter size hail. 

  SOURCE...Radar indicated. 

  IMPACT...Damage to vehicles is expected. 

* Locations impacted include...
  Oskaloosa, Pella, Beacon, University Park, Bussey, Harvey,
  Leighton, Hamilton and Marysville.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

For your protection move to an interior room on the lowest floor of a
building.

&&

LAT...LON 4121 9255 4116 9308 4116 9318 4122 9323
      4149 9270
TIME...MOT...LOC 2201Z 247DEG 35KT 4120 9312 

HAIL...1.00IN
WIND...<50MPH
 
$$

Cogil

3 follow-up statements

024 
WWUS53 KDMX 282211
SVSDMX

Severe Weather Statement
National Weather Service Des Moines IA
411 PM CST TUE FEB 28 2017

IAC123-125-282245-
/O.CON.KDMX.SV.W.0002.000000T0000Z-170228T2245Z/
Marion IA-Mahaska IA-
411 PM CST TUE FEB 28 2017

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 445 PM CST
FOR SOUTHEASTERN MARION AND WESTERN MAHASKA COUNTIES...

At 411 PM CST, a severe thunderstorm was located 7 miles southeast of
Knoxville, moving northeast at 40 mph.

HAZARD...Quarter size hail. 

SOURCE...Radar indicated. 

IMPACT...Damage to vehicles is expected. 

Locations impacted include...
Oskaloosa, Pella, Beacon, University Park, Bussey, Harvey, Leighton,
Hamilton and Marysville.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

For your protection move to an interior room on the lowest floor of a
building.

&&

LAT...LON 4116 9303 4120 9307 4129 9309 4149 9270
      4121 9255
TIME...MOT...LOC 2211Z 247DEG 35KT 4124 9300 

HAIL...1.00IN
WIND...<50MPH
 
$$

Cogil

511 
WWUS53 KDMX 282225
SVSDMX

Severe Weather Statement
National Weather Service Des Moines IA
425 PM CST TUE FEB 28 2017

IAC125-282235-
/O.CAN.KDMX.SV.W.0002.000000T0000Z-170228T2245Z/
Marion IA-
425 PM CST TUE FEB 28 2017

...THE SEVERE THUNDERSTORM WARNING FOR SOUTHEASTERN MARION COUNTY IS
CANCELLED...
    
The severe thunderstorm which prompted the warning has moved out of 
the warned area.  Therefore, the warning has been cancelled.

LAT...LON 4119 9286 4126 9287 4133 9287 4140 9265
      4121 9255
TIME...MOT...LOC 2225Z 250DEG 34KT 4127 9282 

$$

IAC123-282245-
/O.CON.KDMX.SV.W.0002.000000T0000Z-170228T2245Z/
Mahaska IA-
425 PM CST TUE FEB 28 2017

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 445 PM CST
FOR SOUTHWESTERN MAHASKA COUNTY...

At 425 PM CST, a severe thunderstorm was located 9 miles west of
Oskaloosa, moving east at 40 mph.

HAZARD...Quarter size hail. 

SOURCE...Radar indicated. 

IMPACT...Damage to vehicles is expected. 

Locations impacted include...
Oskaloosa, Beacon, University Park and Leighton. 

PRECAUTIONARY/PREPAREDNESS ACTIONS...

For your protection move to an interior room on the lowest floor of a
building.

&&

LAT...LON 4119 9286 4126 9287 4133 9287 4140 9265
      4121 9255
TIME...MOT...LOC 2225Z 250DEG 34KT 4127 9282 

HAIL...1.00IN
WIND...<50MPH
 
$$

Cogil

656 
WWUS53 KDMX 282241
SVSDMX

Severe Weather Statement
National Weather Service Des Moines IA
441 PM CST TUE FEB 28 2017

IAC123-282251-
/O.EXP.KDMX.SV.W.0002.000000T0000Z-170228T2245Z/
Mahaska IA-
441 PM CST TUE FEB 28 2017

...THE SEVERE THUNDERSTORM WARNING FOR SOUTHWESTERN MAHASKA COUNTY
WILL EXPIRE AT 445 PM CST...
        
The storm which prompted the warning has weakened below severe
limits, and has exited the warned area. Therefore, the warning will
be allowed to expire.

LAT...LON 4119 9286 4126 9287 4133 9287 4140 9265
      4121 9255
TIME...MOT...LOC 2241Z 247DEG 35KT 4133 9264 

$$

Kotenberg

The office that day

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

Issued	Product	Office	Counties	Lasted
Feb 28, 4:45 PM CST	Severe Thunderstorm Warning	DMX	Mahaska	15 min

Nearby

Severe Thunderstorm Warnings in Iowa, 2017 Every severe thunderstorm warning in 2017

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.