Alert archive / Iowa / Severe Thunderstorm Warnings in 2012

Severe Thunderstorm Warning 45, NWS Sioux Falls, SD

May 4, 2012Clay County, Iowa

NWS Sioux Falls, SD issued this severe thunderstorm warning at May 4, 2012, 4:25 PM CDT for Clay County, Iowa. It was in force for 35 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: May 4, 2012, 4:25 PM CDT (21:25 UTC)
Expired: May 4, 2012, 5:00 PM CDT
In force: 35 min
Issued by: NWS Sioux Falls, SD
Area: Storm-based polygon
Hail: 1.0 in
Wind: 80.0 mph

County Clay County, IA

The radar

The Sioux Falls radar (KFSD), 155 km from the middle of the area, began a volume at 21:25 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.

What was reported inside it

Time	Report	Where	Remark
May 4, 4:30 PM CDT	TSTM WND GST 60	5 Ne Dickens, IA

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

The watch it was issued in

The SPC watch in force over the same counties when this warning went out.

Issued	Product	Office	Lasted
May 4, 2:00 PM CDT	Severe Thunderstorm Watch	SPC	9 hr

The nearest sounding before it

Omaha, NE (KOAX), launched 12:00Z, 9.4 hours before the alert went out and 223 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: 2705 J/kg
Mixed-layer CIN: -17 J/kg
Mixed-layer LCL: 584 m above ground
0-6 km bulk shear: 17 kt
0-1 km storm-relative helicity: 10 m²/s²
0-3 km storm-relative helicity: 98 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.

422 
WUUS53 KFSD 042125
SVRFSD
IAC041-042200-
/O.NEW.KFSD.SV.W.0045.120504T2125Z-120504T2200Z/

BULLETIN - EAS ACTIVATION REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE SIOUX FALLS SD
425 PM CDT FRI MAY 4 2012

THE NATIONAL WEATHER SERVICE IN SIOUX FALLS HAS ISSUED A

* SEVERE THUNDERSTORM WARNING FOR...
  EASTERN CLAY COUNTY IN NORTHWEST IOWA...

* UNTIL 500 PM CDT

* AT 425 PM CDT...NATIONAL WEATHER SERVICE METEOROLOGISTS WERE
  TRACKING A LINE OF SEVERE THUNDERSTORMS CAPABLE OF PRODUCING
  DESTRUCTIVE WINDS IN EXCESS OF 80 MPH.  THESE STORMS WERE LOCATED
  ALONG A LINE EXTENDING FROM FOSTORIA TO ROYAL TO PETERSON...AND
  MOVING EAST AT 40 MPH.

* SEVERE THUNDERSTORMS WILL BE NEAR...
  WEBB AROUND 445 PM CDT...

AT 422 PM CDT...SPENCER AIRPORT REPORTED A 69 MPH WIND GUST. IN 
ADDITION...AT 424 PM CDT...TREES WERE REPORTED DOWN IN SPENCER DUE 
TO DAMAGING WINDS.

OTHER LOCATIONS IMPACTED BY THESE SEVERE THUNDERSTORMS INCLUDE
DICKENS AND GILLETT GROVE.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

THESE STORMS HAVE A HISTORY OF PRODUCING DESTRUCTIVE WINDS AND LARGE
HAIL. SEEK SHELTER NOW INSIDE A STURDY STRUCTURE AND STAY AWAY FROM
WINDOWS!

WIND DAMAGE WITH THESE STORMS WILL OCCUR WELL AHEAD OF ANY RAIN OR
LIGHTNING. DO NOT WAIT FOR THE SOUND OF THUNDER BEFORE TAKING COVER.
SEEK SHELTER IMMEDIATELY INSIDE A STURDY STRUCTURE AND STAY AWAY FROM
WINDOWS.

&&

LAT...LON 4291 9497 4291 9498 4291 9505 4306 9504
      4326 9507 4325 9491 4313 9491 4312 9490
      4291 9491
TIME...MOT...LOC 2125Z 263DEG 36KT 4327 9515 4307 9513
          4292 9531
WIND...HAIL 80MPH <1.00IN

$$

SCHUMACHER

2 follow-up statements

352 
WWUS53 KFSD 042146
SVSFSD

SEVERE WEATHER STATEMENT
NATIONAL WEATHER SERVICE SIOUX FALLS SD
446 PM CDT FRI MAY 4 2012

IAC041-042200-
/O.CON.KFSD.SV.W.0045.000000T0000Z-120504T2200Z/
CLAY IA-
446 PM CDT FRI MAY 4 2012

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT FOR EASTERN CLAY
COUNTY UNTIL 500 PM CDT...

AT 446 PM CDT...NATIONAL WEATHER SERVICE METEOROLOGISTS WERE TRACKING
A LINE OF SEVERE THUNDERSTORMS CAPABLE OF PRODUCING DESTRUCTIVE WINDS
IN EXCESS OF 70 MPH.  THESE STORMS WERE LOCATED ALONG A LINE
EXTENDING FROM TERRIL TO 12 MILES NORTHEAST OF WEBB TO WEBB...MOVING
EAST AT 40 MPH.

THIS LINE OF SEVERE THUNDERSTORMS WILL AFFECT MAINLY RURAL AREAS OF
EASTERN CLAY COUNTY.

LAT...LON 4291 9505 4306 9504 4310 9504 4325 9491
      4313 9491 4312 9490 4291 9491
TIME...MOT...LOC 2146Z 263DEG 36KT 4329 9486 4309 9484
          4294 9503
WIND...HAIL 70MPH <1.00IN

$$

SCHUMACHER

486 
WWUS53 KFSD 042157
SVSFSD

SEVERE WEATHER STATEMENT
NATIONAL WEATHER SERVICE SIOUX FALLS SD
457 PM CDT FRI MAY 4 2012

IAC041-042207-
/O.EXP.KFSD.SV.W.0045.000000T0000Z-120504T2200Z/
CLAY IA-
457 PM CDT FRI MAY 4 2012

...THE SEVERE THUNDERSTORM WARNING FOR EASTERN CLAY COUNTY WILL
EXPIRE AT 500 PM CDT...

THE LINE OF STORMS WHICH PROMPTED THE WARNING HAVE MOVED OUT OF THE
WARNED AREA.

LAT...LON 4291 9505 4306 9504 4310 9504 4325 9491
      4313 9491 4312 9490 4291 9491
TIME...MOT...LOC 2157Z 263DEG 36KT 4330 9471 4310 9469
          4295 9488

$$

SCHUMACHER

The office that day

Everything else NWS Sioux Falls, SD issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
May 3, 7:57 PM CDT	Severe Thunderstorm Warning	FSD	Cherokee	33 min
May 3, 8:05 PM CDT	Flash Flood Warning	FSD	Cherokee	93 min
May 3, 8:37 PM CDT	Severe Thunderstorm Warning	FSD	Buena Vista, Cherokee	38 min
May 4, 3:00 PM CDT	Severe Thunderstorm Warning	FSD	Sioux	30 min
May 4, 3:14 PM CDT	Severe Thunderstorm Warning	FSD	Plymouth, Sioux	31 min
May 4, 3:18 PM CDT	Severe Thunderstorm Warning	FSD	O'Brien, Osceola, Sioux	42 min
May 4, 3:20 PM CDT	Tornado Warning	FSD	O'Brien, Sioux	25 min
May 4, 3:39 PM CDT	Severe Thunderstorm Warning	FSD	Plymouth	36 min
May 4, 3:43 PM CDT	Tornado Warning	FSD	O'Brien, Sioux	32 min
May 4, 4:01 PM CDT	Severe Thunderstorm Warning	FSD	Cherokee, O'Brien	29 min
May 4, 4:06 PM CDT	Tornado Warning	FSD	Clay	24 min
May 4, 4:09 PM CDT	Severe Thunderstorm Warning	FSD	Dickinson, Osceola	51 min
May 4, 4:12 PM CDT	Severe Thunderstorm Warning	FSD	Clay, O'Brien	33 min

Nearby

Severe Thunderstorm Warnings in Iowa, 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.