Alert archive / Iowa / Tornado Warnings in 2007

Tornado Warning 49, NWS Des Moines, IA

September 30, 2007Calhoun County, Pocahontas County, Sac County, Iowa

NWS Des Moines, IA issued this tornado warning at Sep 30, 2007, 6:21 PM CDT for Calhoun County, Pocahontas County, Sac County, Iowa. It was in force for 24 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 30, 2007, 6:21 PM CDT (23:21 UTC)
Expired
Sep 30, 2007, 6:45 PM CDT
In force
24 min
Issued by
NWS Des Moines, IA
Area
Counties, with a storm outline in the text

Counties Calhoun County, IA, Pocahontas County, IA, Sac County, IA

The radar

The Des Moines radar (KDMX), 131 km from the middle of the area, began a volume at 23:21 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

TimeReportWhereRemark
Sep 30, 6:30 PM CDTTORNADO1 N Lytton, IADELAYED REPORT OF TORNADO TOUCHDOWN NORTH OF LYTTON. TORNADO MOVED NNE AND DISSIPATED A MILE OR TWO EAST OF N28 WEST OF JOLLEY /CALHOUN COUNTY/. ESTIMATED PATH LENGTH IS 2 MILES AND ESTIMATED PATH WIDTH 20-30 YARDS.

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.

IssuedProductOfficeLasted
Sep 30, 1:02 PM CDTTornado WatchSPC7 hr

The nearest sounding before it

Omaha, NE (KOAX), launched 12:00Z, 11.4 hours before the alert went out and 185 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-pSkew-T log-p diagram, Omaha, NE at 12:00Z on 2007-09-30Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 0 joules per kilogram.LCL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Omaha, NE at 12:00Z on 2007-09-30The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 450 square meters per square second.1939587897Sfc1 km3 km6 km9 kmRMLM
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
0 J/kg
Mixed-layer CIN
No buoyant parcel
Mixed-layer LCL
1296 m above ground
0-6 km bulk shear
54 kt
0-1 km storm-relative helicity
450 m²/s²
0-3 km storm-relative helicity
472 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.

000 
WFUS53 KDMX 302321
TORDMX
IAC025-151-161-302345-
/O.NEW.KDMX.TO.W.0049.070930T2321Z-070930T2345Z/

BULLETIN - EAS ACTIVATION REQUESTED
TORNADO WARNING
NATIONAL WEATHER SERVICE DES MOINES IA
621 PM CDT SUN SEP 30 2007

THE NATIONAL WEATHER SERVICE IN DES MOINES HAS ISSUED A

* TORNADO WARNING FOR...
  SOUTHERN POCAHONTAS COUNTY IN NORTHWEST IOWA...
  NORTHWESTERN CALHOUN COUNTY IN WEST CENTRAL IOWA...
  NORTHEASTERN SAC COUNTY IN WEST CENTRAL IOWA...

* UNTIL 645 PM CDT.

* AT 616 PM CDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A
  SEVERE THUNDERSTORM CAPABLE OF PRODUCING A TORNADO 28 MILES
  SOUTHWEST OF POCAHONTAS...OR ABOUT 24 MILES SOUTHEAST OF STORM
  LAKE...MOVING NORTH AT 40 MPH.

* THE TORNADO WILL BE NEAR...
  7 MILES SOUTHWEST OF POCAHONTAS BY 645 PM CDT...

THIS IS A HAZARDOUS SITUATION. SEEK SHELTER IN A BASEMENT...OR IN AN
INTERIOR ROOM. STAY AWAY FROM WINDOWS. IF YOU ARE OUTSIDE OR IN A
CAR...SEEK SHELTER IN A REINFORCED BUILDING.

A TORNADO WATCH REMAINS IN EFFECT UNTIL 800 PM CDT SUNDAY EVENING FOR
WESTERN IOWA.

LAT...LON 4250 9495 4256 9492 4260 9490 4279 9487
      4276 9453 4229 9482 4238 9501
TIME...MOT...LOC 2321Z 201DEG 38KT 4242 9489

$$

DONAVON
2 follow-up statements
000 
WWUS53 KDMX 302333
SVSDMX

SEVERE WEATHER STATEMENT
NATIONAL WEATHER SERVICE DES MOINES IA
632 PM CDT SUN SEP 30 2007

IAC025-151-161-302345-
/O.CON.KDMX.TO.W.0049.000000T0000Z-070930T2345Z/
POCAHONTAS IA-SAC IA-CALHOUN IA-
632 PM CDT SUN SEP 30 2007

...A TORNADO WARNING REMAINS IN EFFECT UNTIL 645 PM CDT FOR
NORTHWESTERN CALHOUN...NORTHEASTERN SAC AND SOUTHERN POCAHONTAS
COUNTIES...

AT 629 PM CDT...TRAINED WEATHER SPOTTERS REPORTED A TORNADO.  THIS
TORNADO WAS LOCATED NEAR LYTTON...OR ABOUT 22 MILES SOUTHEAST OF
STORM LAKE...MOVING NORTHEAST AT 30 MPH.

THE TORNADO WILL BE NEAR...
  JOLLEY BY 640 PM CDT...
  FONDA AND 6 MILES WEST OF POMEROY BY 645 PM CDT...

SEEK SHELTER IN A BASEMENT...OR IN AN INTERIOR ROOM. STAY AWAY FROM
WINDOWS. IF YOU ARE IN A CAR OR OUTSIDE...SEEK SHELTER IN A
REINFORCED BUILDING.

SPOTTERS REPORTED A RAPIDLY ROTATING WALL CLOUD ABOUT A MILE NORTH 
OF HIGHWAY 20 NEAR LYTON.  FUNNEL CLOUD OBSERVED NEARLY ONE HALF WAY 
DOWN TO THE GROUND.

A TORNADO WATCH REMAINS IN EFFECT UNTIL 800 PM CDT SUNDAY EVENING FOR
WESTERN IOWA.

LAT...LON 4250 9495 4256 9492 4260 9490 4279 9487
      4276 9453 4229 9482 4238 9501
TIME...MOT...LOC 2332Z 207DEG 26KT 4246 9485

$$

DONAVON
000 
WWUS53 KDMX 302340
SVSDMX

SEVERE WEATHER STATEMENT
NATIONAL WEATHER SERVICE DES MOINES IA
640 PM CDT SUN SEP 30 2007

IAC161-302350-
/O.CAN.KDMX.TO.W.0049.000000T0000Z-070930T2345Z/
SAC IA-
640 PM CDT SUN SEP 30 2007

...THE TORNADO WARNING FOR NORTHEASTERN SAC COUNTY IS CANCELLED...

AT 638 PM CDT...WEATHER SERVICE DOPPLER RADAR INDICATED THAT THE
THUNDERSTORMS WHICH PROMPTED THE WARNING HAVE EITHER WEAKENED OR
MOVED OUT OF THE AREA...AND NO LONGER POSE AN IMMEDIATE THREAT TO
LIFE OR PROPERTY. THEREFORE...THE TORNADO WARNING HAS BEEN CANCELLED.

A TORNADO WATCH REMAINS IN EFFECT UNTIL 800 PM CDT SUNDAY EVENING FOR
WESTERN IOWA.

LAT...LON 4260 9490 4279 9487 4276 9453 4239 9475
      4236 9478 4236 9479 4247 9487 4251 9492
      4256 9492
TIME...MOT...LOC 2340Z 207DEG 26KT 4251 9481

$$

IAC025-151-302345-
/O.CON.KDMX.TO.W.0049.000000T0000Z-070930T2345Z/
POCAHONTAS IA-CALHOUN IA-
640 PM CDT SUN SEP 30 2007

...A TORNADO WARNING REMAINS IN EFFECT UNTIL 645 PM CDT FOR
NORTHWESTERN CALHOUN AND SOUTHERN POCAHONTAS COUNTIES...

AT 638 PM CDT...TRAINED WEATHER SPOTTERS REPORTED A TORNADO.  THIS
TORNADO WAS LOCATED NEAR JOLLEY...OR ABOUT 22 MILES SOUTHEAST OF
STORM LAKE...MOVING NORTHEAST AT 30 MPH.

THE TORNADO WILL BE NEAR...
  FONDA AND 6 MILES WEST OF POMEROY BY 645 PM CDT...

SEEK SHELTER IN A BASEMENT...OR IN AN INTERIOR ROOM. STAY AWAY FROM
WINDOWS. IF YOU ARE IN A CAR OR OUTSIDE...SEEK SHELTER IN A
REINFORCED BUILDING.

A TORNADO WATCH REMAINS IN EFFECT UNTIL 800 PM CDT SUNDAY EVENING FOR
WESTERN IOWA.

LAT...LON 4260 9490 4279 9487 4276 9453 4239 9475
      4236 9478 4236 9479 4247 9487 4251 9492
      4256 9492
TIME...MOT...LOC 2340Z 207DEG 26KT 4251 9481

$$

DONAVON

The office that day

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

IssuedProductOfficeCountiesLasted
Sep 30, 4:29 PM CDTSevere Thunderstorm WarningDMXRinggold31 min
Sep 30, 4:38 PM CDTSevere Thunderstorm WarningDMXUnion27 min
Sep 30, 4:43 PM CDTHigh Wind WarningDMXAdair, Adams, Audubon, Carroll, Cass, Clarke and 8 more3 hr
Sep 30, 4:49 PM CDTSevere Thunderstorm WarningDMXClarke, Madison, Warren56 min
Sep 30, 5:21 PM CDTSevere Thunderstorm WarningDMXClarke, Lucas24 min
Sep 30, 5:23 PM CDTTornado WarningDMXClarke, Lucas24 min
Sep 30, 5:25 PM CDTSevere Thunderstorm WarningDMXSac50 min
Sep 30, 5:33 PM CDTTornado WarningDMXMarion, Warren42 min
Sep 30, 6:03 PM CDTSevere Thunderstorm WarningDMXJasper57 min
Sep 30, 6:03 PM CDTTornado WarningDMXSac15 min
Sep 30, 6:17 PM CDTSevere Thunderstorm WarningDMXCalhoun, Pocahontas, Sac43 min
Sep 30, 6:18 PM CDTSevere Thunderstorm WarningDMXMahaska, Marion, Poweshiek42 min
Sep 30, 6:21 PM CDTTornado WarningDMXJasper, Mahaska, Marion, Poweshiek39 min
Sep 30, 6:37 PM CDTTornado WarningDMXPoweshiek38 min
Sep 30, 6:47 PM CDTTornado WarningDMXCalhoun, Pocahontas15 min
Sep 30, 6:54 PM CDTTornado WarningDMXJasper, Mahaska, Marion, Poweshiek26 min

Nearby

Tornado Warnings in Iowa, 2007Every tornado warning in 2007Tornadoes in 2007

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.