Alert archive / Arkansas / Tornado Warnings in 2011

Tornado Warning 12, NWS Shreveport, LA

April 15, 2011Howard County, Sevier County, Arkansas

NWS Shreveport, LA issued this tornado warning at Apr 15, 2011, 12:21 AM CDT for Howard County, Sevier County, Arkansas. It was in force for 39 min. No storm report in the archive falls inside the area while it was in force.

The area

The outline as issued.

The facts

Issued: Apr 15, 2011, 12:21 AM CDT (05:21 UTC)
Expired: Apr 15, 2011, 1:00 AM CDT
In force: 39 min
Issued by: NWS Shreveport, LA
Area: Storm-based polygon

Counties Howard County, AR, Sevier County, AR

The radar

The Western Arkansas radar (KSRX), 120 km from the middle of the area, began a volume at 05:22 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 14, 9:06 PM CDT	Tornado Watch	SPC	6 hr

The nearest sounding before it

Shreveport, LA (KSHV), launched 00:00Z, 5.4 hours before the alert went out and 197 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: 1201 J/kg
Mixed-layer CIN: -8 J/kg
Mixed-layer LCL: 1314 m above ground
0-6 km bulk shear: 54 kt
0-1 km storm-relative helicity: 117 m²/s²
0-3 km storm-relative helicity: 135 m²/s²
Significant tornado parameter: 0.8
Supercell composite: 6.5

Open this sounding in Storm Lab

The text

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

354 
WFUS54 KSHV 150521
TORSHV
ARC061-133-150600-
/O.NEW.KSHV.TO.W.0012.110415T0521Z-110415T0600Z/

BULLETIN - EAS ACTIVATION REQUESTED
TORNADO WARNING
NATIONAL WEATHER SERVICE SHREVEPORT LA
1221 AM CDT FRI APR 15 2011

THE NATIONAL WEATHER SERVICE IN SHREVEPORT HAS ISSUED A

* TORNADO WARNING FOR...
  HOWARD COUNTY IN SOUTHWEST ARKANSAS...
  THIS INCLUDES THE CITIES OF...UMPIRE...DIERKS...
  CENTRAL SEVIER COUNTY IN SOUTHWEST ARKANSAS...

* UNTIL 100 AM CDT

* AT 1219 AM CDT...NATIONAL WEATHER SERVICE METEOROLOGISTS DETECTED A
  SEVERE THUNDERSTORM CAPABLE OF PRODUCING A TORNADO 6 MILES WEST OF
  DIERKS...MOVING EAST AT 55 MPH.

* OTHER LOCATIONS IN THE WARNING INCLUDE BUT ARE NOT LIMITED TO
  ATHENS...CENTER POINT AND CORINTH...

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A TORNADO WARNING MEANS THAT STRONG ROTATION HAS BEEN DETECTED IN THE
STORM. A TORNADO MAY ALREADY BE ON THE GROUND...OR IS EXPECTED TO
DEVELOP SHORTLY. IF YOU ARE IN THE PATH OF THIS DANGEROUS STORM...
MOVE INDOORS AND TO THE LOWEST LEVEL OF THE BUILDING. STAY AWAY FROM
WINDOWS. IF DRIVING...DO NOT SEEK SHELTER UNDER A HIGHWAY OVERPASS.

&&

LAT...LON 3436 9393 3435 9392 3419 9391 3418 9380
      3397 9382 3396 9423 3420 9426 3421 9425
      3435 9426 3436 9425 3436 9404
TIME...MOT...LOC 0521Z 269DEG 46KT 3413 9409

$$

05

The office that day

Everything else NWS Shreveport, LA issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Apr 14, 11:37 PM CDT	Tornado Warning	SHV	Sevier	38 min
Apr 15, 12:18 AM CDT	Severe Thunderstorm Warning	SHV	Howard, Sevier	57 min
Apr 15, 12:26 AM CDT	Severe Thunderstorm Warning	SHV	Hempstead, Howard, Little River, Miller, Sevier	64 min
Apr 15, 12:30 AM CDT	Severe Thunderstorm Warning	SHV	Miller	60 min
Apr 15, 1:14 AM CDT	Severe Thunderstorm Warning	SHV	Hempstead, Howard, Lafayette, Little River, Miller, Nevada	61 min
Apr 15, 2:07 AM CDT	Severe Thunderstorm Warning	SHV	Columbia, Lafayette, Miller	53 min
Apr 15, 2:46 AM CDT	Severe Thunderstorm Warning	SHV	Columbia, Union	59 min

Nearby

Tornado Warnings in Arkansas, 2011 Every tornado warning in 2011 Tornadoes in 2011

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.