Alert archive / Arkansas / Mesoscale Discussions in 2011

Mesoscale Discussion 564

April 25, 20114 counties in Arkansas

The Storm Prediction Center issued this mesoscale discussion at Apr 25, 2011, 1:57 AM CDT for 4 counties in Arkansas. It was in force for 63 min.

The area

The outline as issued.

The facts

Issued: Apr 25, 2011, 1:57 AM CDT (06:57 UTC)
Expired: Apr 25, 2011, 3:00 AM CDT
In force: 63 min
Issued by: the Storm Prediction Center

Counties Cleveland County, AR, Dallas County, AR, Jefferson County, AR, Lincoln County, AR

The radar

The Little Rock radar (KLZK), 90 km from the middle of the area, began a volume at 07:00 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

Shreveport, LA (KSHV), launched 00:00Z, 7.0 hours before the alert went out and 220 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: 253 J/kg
Mixed-layer CIN: -162 J/kg
Mixed-layer LCL: 1930 m above ground
0-6 km bulk shear: 29 kt
0-1 km storm-relative helicity: 44 m²/s²
0-3 km storm-relative helicity: 72 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 1.1

Open this sounding in Storm Lab

The text

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

971 
ACUS11 KWNS 250658
SWOMCD
SPC MCD 250657
ARZ000-250800-

MESOSCALE DISCUSSION 0564
NWS STORM PREDICTION CENTER NORMAN OK
0157 AM CDT MON APR 25 2011

AREAS AFFECTED...SRN AR

CONCERNING...SEVERE POTENTIAL...WATCH POSSIBLE

VALID 250657Z - 250800Z

SOME THREAT FOR SEVERE WEATHER MIGHT EXTEND FARTHER EWD INTO SRN AR
WITH PRIMARY THREAT BEING DAMAGING WIND. HOWEVER...MAGNITUDE OF THE
THREAT REMAINS UNCERTAIN...AND WW ISSUANCE WILL ULTIMATELY DEPEND ON
CONVECTIVE TRENDS.

BOWING LINE SEGMENT IN SWRN AR IS MOVING ENEWD AT 40-45 KT. A LARGE
CONVECTIVE OUTFLOW BOUNDARY FROM MCS ACROSS CNTRL AND NRN ARKANSAS
ARCS SWWD TO THE STORM IN SWRN ARKANSAS AND IS MOVING SEWD. IT
APPEARS THE BOWING SEGMENT WILL REMAIN ON COOL SIDE OF THE OUTFLOW
BOUNDARY WHERE ELEVATED CONVECTION IS ALSO OCCURRING. THE STABLE
NEAR SURFACE AIR NORTH OF THE OUTFLOW BOUNDARY COULD POTENTIALLY
SERVE AS A LIMITING FACTOR FOR STRONGER WIND GUSTS REACHING THE
SURFACE...BUT THIS AIR IS NOT PARTICULARLY COLD WITH TEMPERATURES
AROUND 60. NEVERTHELESS...INFLUX OF HIGHER THETA-E AIR ALONG STRONG
SSWLY LLJ MIGHT HELP SUSTAIN THE STORM FARTHER EWD THROUGH SRN AR
WITH PRIMARY THREAT BEING DAMAGING WIND.

..DIAL.. 04/25/2011

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

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

LAT...LON   33959304 34149248 34509172 34359144 33979150 33689210
            33689282 33959304

SPC that day

Everything else SPC issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Apr 24, 10:13 PM CDT	Mesoscale Discussion	SPC	Clark, Cleburne, Conway, Faulkner, Garland, Grant and 15 more	2 hr
Apr 24, 11:43 PM CDT	Severe Thunderstorm Watch	SPC	Hempstead, Howard, Little River, Miller, Nevada, Sevier	5 hr
Apr 25, 4:41 AM CDT	Severe Thunderstorm Watch	SPC	Arkansas, Bradley, Calhoun, Clark, Cleveland, Columbia and 25 more	7 hr
Apr 25, 7:23 AM CDT	Mesoscale Discussion	SPC	Calhoun, Clark, Cleveland, Columbia, Dallas, Garland and 11 more	97 min
Apr 25, 8:37 AM CDT	Mesoscale Discussion	SPC	Arkansas, Cleveland, Crittenden, Desha, Drew, Jefferson and 7 more	53 min
Apr 25, 9:17 AM CDT	Severe Thunderstorm Watch	SPC	Crittenden, Lee, Phillips, St. Francis	6 hr
Apr 25, 10:46 AM CDT	Mesoscale Discussion	SPC	Hempstead, Howard, Lafayette, Little River, Miller, Sevier	59 min
Apr 25, 11:00 AM CDT	Tornado Watch	SPC	Carroll, Clark, Crawford, Franklin, Hempstead, Howard and 13 more	7 hr
Apr 25, 1:15 PM CDT	Mesoscale Discussion	SPC	Crittenden, Cross, Lee, Phillips, St. Francis	60 min
Apr 25, 1:28 PM CDT	Mesoscale Discussion	SPC	Crawford, Franklin, Howard, Johnson, Little River, Logan and 5 more	92 min
Apr 25, 3:08 PM CDT	Mesoscale Discussion	SPC	Arkansas, Ashley, Baxter, Boone, Bradley, Calhoun and 29 more	37 min
Apr 25, 3:22 PM CDT	Tornado Watch PDS	SPC	Arkansas, Baxter, Boone, Bradley, Calhoun, Clark and 50 more	8 hr
Apr 25, 4:34 PM CDT	Mesoscale Discussion	SPC	Arkansas, Clay, Craighead, Crittenden, Cross, Greene and 11 more	56 min
Apr 25, 4:50 PM CDT	Tornado Watch PDS	SPC	Clay, Craighead, Crittenden, Cross, Greene, Lee and 4 more	7 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.