Alert archive / Oklahoma / Tornado Warnings in 2001

Tornado Warning 4, NWS Norman, OK

April 11, 2001Pottawatomie County, Oklahoma

NWS Norman, OK issued this tornado warning at Apr 11, 2001, 1:56 AM CDT for Pottawatomie County, Oklahoma. It was in force for 34 min. No storm report in the archive falls inside the area while it was in force.

The area

The outline the Iowa Environmental Mesonet reconstructed for it; the warning itself named whole counties.

The facts

Issued: Apr 11, 2001, 1:56 AM CDT (06:56 UTC)
Expired: Apr 11, 2001, 2:30 AM CDT
In force: 34 min
Issued by: NWS Norman, OK
Area: Whole counties; the outline is the Mesonet’s reconstruction

County Pottawatomie County, OK

The radar

The Norman radar (KTLX), 35 km from the middle of the area, began a volume at 06:57 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 nearest sounding before it

Norman, OK (KOUN), launched 00:00Z, 6.9 hours before the alert went out and 38 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: 1767 J/kg
Mixed-layer CIN: -45 J/kg
Mixed-layer LCL: 678 m above ground
0-6 km bulk shear: 63 kt
0-1 km storm-relative helicity: 114 m²/s²
0-3 km storm-relative helicity: 192 m²/s²
Significant tornado parameter: 1.0
Supercell composite: 3.8

Open this sounding in Storm Lab

The text

As transmitted, in the capitals the NWS used until 2016.

000 
WFUS54 KOUN 110656
TOROKC
OKC125-110730-

BULLETIN - EAS ACTIVATION REQUESTED
TORNADO WARNING
NATIONAL WEATHER SERVICE NORMAN OK
156 AM CDT WED APR 11 2001

THE NATIONAL WEATHER SERVICE IN NORMAN HAS ISSUED A

* TORNADO WARNING FOR...
  POTTAWATOMIE COUNTY IN CENTRAL OKLAHOMA

* UNTIL 230 AM CDT

* AT 156 AM CDT...DOPPLER RADAR DETECTED A SEVERE THUNDERSTORM
  CAPABLE OF PRODUCING A TORNADO 9 MILES SOUTHWEST OF WANETTE...
  MOVING NORTHEAST AT 45 MPH.

* LOCATIONS IN THE WARNING INCLUDE ASHER...BROOKSVILLE...MACOMB...
  MAUD...ST. LOUIS...TRIBBEY AND WANETTE

TORNADOES ARE ESPECIALLY DANGEROUS AT NIGHT BECAUSE THEY ARE HARD TO
SEE. TAKE COVER NOW. IF A BASEMENT IS NOT AVAILABLE...MOVE TO AN
INTERIOR ROOM OR HALLWAY ON THE LOWEST FLOOR. LEAVE MOBILE HOMES AND
VEHICLES FOR REINFORCED SHELTER. STAY AWAY FROM WINDOWS.

LAT...LON 3513 9715 3494 9715 3498 9678 3524 9678
          3524 9700

The office that day

Everything else NWS Norman, OK issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Apr 11, 1:22 AM CDT	Severe Thunderstorm Warning	OUN	Dewey, Woodward	38 min
Apr 11, 1:44 AM CDT	Tornado Warning	OUN	Garvin, McClain	31 min
Apr 11, 2:17 AM CDT	Tornado Warning	OUN	Pottawatomie	28 min
Apr 11, 2:56 AM CDT	Tornado Warning	OUN	Pottawatomie, Seminole	34 min
Apr 11, 3:58 AM CDT	Tornado Warning	OUN	Love	32 min
Apr 11, 4:41 AM CDT	Severe Thunderstorm Warning	OUN	Coal, Pontotoc	34 min
Apr 11, 5:05 AM CDT	Severe Thunderstorm Warning	OUN	Atoka, Coal, Johnston	25 min
Apr 11, 5:12 AM CDT	Severe Thunderstorm Warning	OUN	Hughes	33 min
Apr 11, 5:30 AM CDT	Severe Thunderstorm Warning	OUN	Atoka, Bryan	45 min

Nearby

Tornado Warnings in Oklahoma, 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.