Alert archive / Iowa / Tornado Warnings in 2001

Tornado Warning 9, NWS Omaha, NE

April 11, 2001Pottawattamie County, Iowa

NWS Omaha, NE issued this tornado warning at Apr 11, 2001, 1:12 PM CDT for Pottawattamie County, Iowa. It was in force for 18 min. No storm report in the archive falls inside the area while it was in force.

The area

The counties it named.

The facts

Issued: Apr 11, 2001, 1:12 PM CDT (18:12 UTC)
Expired: Apr 11, 2001, 1:30 PM CDT
In force: 18 min
Issued by: NWS Omaha, NE
Area: Whole counties

County Pottawattamie County, IA

The radar

The Omaha radar (KOAX), 69 km from the middle of the area, began a volume at 18:16 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.

The watch it was issued in

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

Issued	Product	Office	Lasted
Apr 11, 10:45 AM CDT	Tornado Watch	SPC	5 hr

The nearest sounding before it

Omaha, NE (KOAX), launched 12:00Z, 6.2 hours before the alert went out and 69 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: 0 J/kg
Mixed-layer CIN: No buoyant parcel
Mixed-layer LCL: 1274 m above ground
0-6 km bulk shear: 77 kt
0-1 km storm-relative helicity: 17 m²/s²
0-3 km storm-relative helicity: 163 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 KOAX 111813
TOROMA
IAC155-111830-

BULLETIN - EAS ACTIVATION REQUESTED
TORNADO WARNING
NATIONAL WEATHER SERVICE OMAHA NE
112 PM CDT WED APR 11 2001

THE NATIONAL WEATHER SERVICE IN OMAHA HAS ISSUED A

* TORNADO WARNING FOR...
  POTTAWATTAMIE COUNTY IN SOUTHWEST IOWA

* UNTIL 130 PM CDT

* AT 111 PM CDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED 
A   TORNADO 5 MILES WEST OF HANCOCK...MOVING NORTH AT 40 MPH.

* THE TORNADO IS EXPECTED TO BE NEAR...
RURAL NORTHERN POTTAWATTAMIE COUNTY AROUND 120 PM CDT

A TORNADO WATCH REMAINS IN EFFECT UNTIL 400 PM CDT WEDNESDAY
AFTERNOON FOR SOUTHWESTERN IOWA AND EASTERN NEBRASKA.

TAKE SHELTER IF YOU ARE IN THE PATH OF THIS STORM.

L8AT...LON 4141 9569 4128 9552 4150 9533 4150 9559

ZAPOTOCNY

The office that day

Everything else NWS Omaha, NE issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Apr 11, 12:20 AM CDT	Severe Thunderstorm Warning	OAX	Monona	40 min
Apr 11, 3:21 AM CDT	Severe Thunderstorm Warning	OAX	Fremont	39 min
Apr 11, 3:34 AM CDT	Severe Thunderstorm Warning	OAX	Mills	41 min
Apr 11, 3:45 AM CDT	Severe Thunderstorm Warning	OAX	Montgomery, Page	45 min
Apr 11, 3:57 AM CDT	Severe Thunderstorm Warning	OAX	Pottawattamie	48 min
Apr 11, 12:38 PM CDT	Tornado Warning	OAX	Mills	37 min
Apr 11, 12:45 PM CDT	Tornado Warning	OAX	Pottawattamie	30 min
Apr 11, 1:04 PM CDT	Tornado Warning	OAX	Harrison	26 min
Apr 11, 1:29 PM CDT	Tornado Warning	OAX	Shelby	31 min
Apr 11, 1:30 PM CDT	Tornado Warning	OAX	Harrison	30 min
Apr 11, 1:40 PM CDT	Tornado Warning	OAX	Monona	35 min

Nearby

Tornado Warnings in Iowa, 2001 Every tornado warning in 2001 Tornadoes in 2001

Sources

The product and its follow-ups from the Iowa Environmental Mesonet's archive of National Weather Service and Storm Prediction Center text; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.