Alert archive / Arkansas / Mesoscale Discussions in 2011

Mesoscale Discussion 908

May 23, 201117 counties in Arkansas

The Storm Prediction Center issued this mesoscale discussion at May 23, 2011, 6:18 PM CDT for 17 counties in Arkansas. It was in force for 87 min.

The area

The outline as issued.

The facts

Issued: May 23, 2011, 6:18 PM CDT (23:18 UTC)
Expired: May 23, 2011, 7:45 PM CDT
In force: 87 min
Issued by: the Storm Prediction Center

Counties Cleburne County, AR, Craighead County, AR, Crittenden County, AR, Cross County, AR, Faulkner County, AR, Independence County, AR, Izard County, AR, Jackson County, AR, Marion County, AR, Mississippi County, AR, Poinsett County, AR, Searcy County, AR, St. Francis County, AR, Stone County, AR, Van Buren County, AR, White County, AR, Woodruff County, AR

The radar

The Little Rock radar (KLZK), 115 km from the middle of the area, began a volume at 23:20 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 watches that followed

Watches SPC issued over any of the same counties within four hours of this discussion.

Severe Thunderstorm Watch 350May 23, 9:45 PM CDT

The nearest sounding before it

Little Rock, AR (KLZK), launched 12:00Z, 11.3 hours before the alert went out and 178 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: 2279 J/kg
Mixed-layer CIN: -67 J/kg
Mixed-layer LCL: 553 m above ground
0-6 km bulk shear: 41 kt
0-1 km storm-relative helicity: 184 m²/s²
0-3 km storm-relative helicity: 229 m²/s²
Significant tornado parameter: 2.1
Supercell composite: 10.2

Open this sounding in Storm Lab

The text

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

560 
ACUS11 KWNS 232318
SWOMCD
SPC MCD 232318 
TNZ000-ARZ000-240045-

MESOSCALE DISCUSSION 0908
NWS STORM PREDICTION CENTER NORMAN OK
0618 PM CDT MON MAY 23 2011

AREAS AFFECTED...NRN AR

CONCERNING...SEVERE THUNDERSTORM WATCH 343...

VALID 232318Z - 240045Z

THE SEVERE WEATHER THREAT FOR SEVERE THUNDERSTORM WATCH 343
CONTINUES.

STORMS WILL CONTINUE DEVELOPING ACROSS NRN AR THROUGH MID EVENING.
THREAT WILL PERSIST FOR ISOLATED DAMAGING WIND AND HAIL...MAINLY
OVER THE SWRN HALF OF WW 345. 

ISENTROPIC LIFT AND MOIST UNSTABLE INFLOW RESULTING FROM A
PERSISTENT 40 KT SWLY LLJ WILL CONTINUE TO PROMOTE THUNDERSTORM
DEVELOPMENT OVER NRN AR...ALONG AND NORTH OF CONVECTIVE OUTFLOW
BOUNDARY. TENDENCY HAS BEEN FOR STORMS TO REMAIN ON THE COOL SIDE
WHERE THEY MAY BE SLIGHTLY ELEVATED. HOWEVER...RECENT RADAR TRENDS
INDICATE NUMEROUS STORM MERGERS IN THE PROCESS OF DEVELOPING FROM
NERN OK INTO SWRN MO AND EXTREME NWRN AR. THIS ACTIVITY MIGHT
EVENTUALLY ORGANIZE INTO A FORWARD PROPAGATING MCS AND ADVANCE ESEWD
ON THE COOL SIDE OF THE BOUNDARY. IF THIS OCCURS...THE THREAT FOR
DAMAGING WIND WOULD INCREASE LATER THIS EVENING.

..DIAL.. 05/23/2011

...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT...

ATTN...WFO...MEG...LZK...

LAT...LON   36379278 35919124 35918976 35308999 34889085 35089230
            35899303 36379278

SPC that day

Everything else SPC issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
May 22, 7:52 PM CDT	Mesoscale Discussion	SPC	Baxter, Benton, Boone, Carroll, Conway, Crawford and 13 more	53 min
May 22, 8:47 PM CDT	Tornado Watch	SPC	Baxter, Benton, Boone, Carroll, Clay, Cleburne and 34 more	7 hr
May 22, 11:46 PM CDT	Mesoscale Discussion	SPC	Clay, Cleburne, Conway, Craighead, Crawford, Cross and 23 more	89 min
May 23, 5:07 AM CDT	Mesoscale Discussion	SPC	Baxter, Benton, Boone, Carroll, Crawford, Fulton and 10 more	113 min
May 23, 7:38 AM CDT	Mesoscale Discussion	SPC	Benton, Carroll	97 min
May 23, 9:14 AM CDT	Mesoscale Discussion	SPC	Clark, Cleburne, Conway, Crawford, Dallas, Faulkner and 26 more	91 min
May 23, 9:57 AM CDT	Mesoscale Discussion	SPC	Lafayette, Little River, Miller	33 min
May 23, 10:34 AM CDT	Mesoscale Discussion	SPC	Benton, Carroll, Fulton	86 min
May 23, 12:10 PM CDT	Mesoscale Discussion	SPC	Lafayette, Miller	65 min
May 23, 12:12 PM CDT	Mesoscale Discussion	SPC	Baxter, Benton, Boone, Carroll, Clay, Craighead and 13 more	93 min
May 23, 1:16 PM CDT	Mesoscale Discussion	SPC	Baxter, Clay, Craighead, Fulton, Greene, Independence and 5 more	89 min
May 23, 1:34 PM CDT	Severe Thunderstorm Watch	SPC	Clay, Cleburne, Conway, Craighead, Crittenden, Cross and 20 more	6 hr
May 23, 3:58 PM CDT	Mesoscale Discussion	SPC	Clay, Cleburne, Conway, Craighead, Crittenden, Cross and 20 more	92 min
May 23, 5:07 PM CDT	Mesoscale Discussion	SPC	Benton, Crawford, Washington	23 min
May 23, 5:24 PM CDT	Tornado Watch	SPC	Crawford, Franklin, Sebastian, Washington	4 hr

Nearby

Mesoscale Discussions in Arkansas, 2011 Every mesoscale discussion 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.