Alert archive / Arkansas / Severe Thunderstorm Watches in 2005

Severe Thunderstorm Watch 21

February 21, 200517 counties in Arkansas

The Storm Prediction Center issued this severe thunderstorm watch at Feb 21, 2005, 2:30 AM CST for 17 counties in Arkansas. It was in force for 4 hr.

The area

The outline as issued.

The facts

Issued
Feb 21, 2005, 2:30 AM CST (08:30 UTC)
Expired
Feb 21, 2005, 6:00 AM CST
In force
4 hr
Issued by
the Storm Prediction Center

Counties Baxter County, AR, Boone County, AR, Cleburne County, AR, Conway County, AR, Fulton County, AR, Independence County, AR, Izard County, AR, Jackson County, AR, Lawrence County, AR, Marion County, AR, Pope County, AR, Randolph County, AR, Searcy County, AR, Sharp County, AR, Stone County, AR, Van Buren County, AR, White County, AR

The radar

The Little Rock radar (KLZK), 131 km from the middle of the area, began a volume at 08:30 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.

Warnings issued inside it

8 tornado, severe thunderstorm and flash flood warnings for its counties while it was in force.

IssuedProductOfficeCountiesLasted
Feb 21, 2:56 AM CSTSevere Thunderstorm WarningLZKPope, Searcy64 min
Feb 21, 3:11 AM CSTSevere Thunderstorm WarningLZKBaxter, Marion49 min
Feb 21, 3:30 AM CSTSevere Thunderstorm WarningLZKConway, Stone, Van Buren60 min
Feb 21, 3:36 AM CSTSevere Thunderstorm WarningLZKFulton, Izard39 min
Feb 21, 3:59 AM CSTSevere Thunderstorm WarningLZKCleburne, Faulkner, Independence, Sharp61 min
Feb 21, 4:27 AM CSTSevere Thunderstorm WarningMEGLawrence, Randolph48 min
Feb 21, 4:30 AM CSTSevere Thunderstorm WarningLZKWhite60 min
Feb 21, 5:16 AM CSTSevere Thunderstorm WarningLZKJackson, Monroe, Prairie, Woodruff59 min

Discussions around it

SPC mesoscale discussions over the same counties from four hours before the watch to its end.

The nearest sounding before it

Springfield, MO (KSGF), launched 00:00Z, 8.5 hours before the alert went out and 169 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, Springfield, MO at 00:00Z on 2005-02-21Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 424 joules per kilogram.LCLLFCEL10008507005003002001001 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, Springfield, MO at 00:00Z on 2005-02-21The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 69 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
424 J/kg
Mixed-layer CIN
-21 J/kg
Mixed-layer LCL
1413 m above ground
0-6 km bulk shear
49 kt
0-1 km storm-relative helicity
69 m²/s²
0-3 km storm-relative helicity
134 m²/s²
Significant tornado parameter
0.1
Supercell composite
1.3

Open this sounding in Storm Lab

The text

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

000 
WWUS20 KWNS 210827
SEL1  
SPC WW 210827
ARZ000-211200-

URGENT - IMMEDIATE BROADCAST REQUESTED
SEVERE THUNDERSTORM WATCH NUMBER 21
NWS STORM PREDICTION CENTER NORMAN OK
230 AM CST MON FEB 21 2005

THE NWS STORM PREDICTION CENTER HAS ISSUED A
SEVERE THUNDERSTORM WATCH FOR PORTIONS OF 

       NORTHERN ARKANSAS

EFFECTIVE THIS MONDAY MORNING FROM 230 AM UNTIL 600 AM CST.

HAIL TO 1.5 INCHES IN DIAMETER...THUNDERSTORM WIND GUSTS TO 80
MPH...AND DANGEROUS LIGHTNING ARE POSSIBLE IN THESE AREAS.

THE SEVERE THUNDERSTORM WATCH AREA IS APPROXIMATELY ALONG AND 45
STATUTE MILES NORTH AND SOUTH OF A LINE FROM 25 MILES SOUTH OF
HARRISON ARKANSAS TO 20 MILES SOUTH OF WALNUT RIDGE ARKANSAS.  FOR
A COMPLETE DEPICTION OF THE WATCH SEE THE ASSOCIATED WATCH OUTLINE
UPDATE (WOUS64 KWNS WOU1).

REMEMBER...A SEVERE THUNDERSTORM WATCH MEANS CONDITIONS ARE
FAVORABLE FOR SEVERE THUNDERSTORMS IN AND CLOSE TO THE WATCH AREA.
PERSONS IN THESE AREAS SHOULD BE ON THE LOOKOUT FOR THREATENING
WEATHER CONDITIONS AND LISTEN FOR LATER STATEMENTS AND POSSIBLE
WARNINGS. SEVERE THUNDERSTORMS CAN AND OCCASIONALLY DO PRODUCE
TORNADOES.

OTHER WATCH INFORMATION...THIS SEVERE THUNDERSTORM WATCH REPLACES
SEVERE THUNDERSTORM WATCH NUMBER 19. WATCH NUMBER 19 WILL NOT BE
IN EFFECT AFTER 230 AM CST. CONTINUE...WW 20...

DISCUSSION...SEVERE BOW ECHO EXPECTED TO MOVE EWD 50-60 KT ACROSS
NRN AR OZARKS WITH CONTINUED THREAT OF DAMAGING WIND...IN FAVORABLY
UNSTABLE AIR MASS.

AVIATION...A FEW SEVERE THUNDERSTORMS WITH HAIL SURFACE AND ALOFT
TO 1.5 INCHES. EXTREME TURBULENCE AND SURFACE WIND GUSTS TO 70
KNOTS. A FEW CUMULONIMBI WITH MAXIMUM TOPS TO 450. MEAN STORM
MOTION VECTOR 24050.


...Edwards/Hart

363,0930 362,0905 351,0905 351,0930

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Feb 20, 8:51 PM CSTMesoscale DiscussionSPCBaxter, Boone, Carroll, Cleburne, Conway, Crawford and 27 more114 min
Feb 20, 9:10 PM CSTSevere Thunderstorm WatchSPCBaxter, Benton, Boone, Carroll, Cleburne, Conway and 29 more6 hr
Feb 20, 11:22 PM CSTMesoscale DiscussionSPCBaxter, Benton, Boone, Carroll, Clay, Cleburne and 42 more113 min
Feb 21, 12:30 AM CSTSevere Thunderstorm WatchSPCClay, Craighead, Crittenden, Cross, Greene, Jackson and 8 more6 hr
Feb 21, 2:10 AM CSTMesoscale DiscussionSPCBaxter, Benton, Boone, Carroll, Clay, Cleburne and 43 more95 min
Feb 21, 4:29 AM CSTMesoscale DiscussionSPCBaxter, Boone, Clay, Cleburne, Conway, Craighead and 16 more2 hr
Feb 21, 5:45 AM CSTSevere Thunderstorm WatchSPCClay, Craighead, Crittenden, Cross, Greene, Lee and 4 more3 hr
Feb 21, 7:50 AM CSTMesoscale DiscussionSPCClay, Craighead, Crittenden, Cross, Greene, Lee and 4 more55 min
Feb 21, 3:58 PM CSTMesoscale DiscussionSPCArkansas, Desha, Drew, Jefferson, Lincoln, Phillips92 min

Nearby

Severe Thunderstorm Watches in Arkansas, 2005Every severe thunderstorm watch in 2005

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.