Alert archive / Arkansas / Mesoscale Discussions in 2005

Mesoscale Discussion 708

April 29, 200519 counties in Arkansas; Bowie County, Cass County, Texas

The Storm Prediction Center issued this mesoscale discussion at Apr 29, 2005, 2:28 PM CDT for 19 counties in Arkansas; Bowie County, Cass County, Texas. It was in force for 107 min.

The area

The outline as issued.

The facts

Issued
Apr 29, 2005, 2:28 PM CDT (19:28 UTC)
Expired
Apr 29, 2005, 4:15 PM CDT
In force
107 min
Issued by
the Storm Prediction Center
All 21 counties

Bradley County, AR, Calhoun County, AR, Clark County, AR, Cleveland County, AR, Columbia County, AR, Dallas County, AR, Grant County, AR, Hempstead County, AR, Howard County, AR, Jefferson County, AR, Lafayette County, AR, Lincoln County, AR, Little River County, AR, Miller County, AR, Nevada County, AR, Ouachita County, AR, Pike County, AR, Sevier County, AR, Union County, AR, Bowie County, TX, Cass County, TX

The radar

The Shreveport radar (KSHV), 148 km from the middle of the area, began a volume at 19:31 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.

The nearest sounding before it

Shreveport, LA (KSHV), launched 12:00Z, 7.5 hours before the alert went out and 142 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, Shreveport, LA at 12:00Z on 2005-04-29Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 23 joules per kilogram.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°0°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Shreveport, LA at 12:00Z on 2005-04-29The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 134 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
23 J/kg
Mixed-layer CIN
-691 J/kg
Mixed-layer LCL
941 m above ground
0-6 km bulk shear
47 kt
0-1 km storm-relative helicity
134 m²/s²
0-3 km storm-relative helicity
116 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

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

000 
ACUS11 KWNS 291929
SWOMCD
SPC MCD 291928 COR
ARZ000-LAZ000-TXZ000-292115-

MESOSCALE DISCUSSION 0708
NWS STORM PREDICTION CENTER NORMAN OK
0228 PM CDT FRI APR 29 2005

AREAS AFFECTED...ARKLATEX THRU SRN AR

CONCERNING...SEVERE THUNDERSTORM POTENTIAL 

VALID 291928Z - 292115Z

CORRECTED MD GRAPHIC

TRENDS ARE BEING MONITORED FOR POSSIBILITY OF A TORNADO WATCH.

DESPITE SUBSTANTIAL CLOUD COVER...MOIST WARM SECTOR BOUNDARY LAYER
CONTINUES TO WARM/DEEPEN ALONG AND SOUTH OF OUTFLOW BOUNDARY ACROSS
SOUTH CENTRAL ARKANSAS INTO VICINITY OF SURFACE LOW NEAR TEXARKANA. 
SOME DEEPENING OF LOW IS OCCURRING...BUT PRIMARY UPSTREAM SOUTHERN
BRANCH IMPULSE IS JUST NOW BEGINNING TO SHIFT INTO THE SOUTHERN
ROCKIES.  DOWNSTREAM MID/UPPER RIDGING IS EVIDENT IN SATELLITE
IMAGERY...AND MAY TEND TO DELAY/SUPPRESS DEEP CONVECTIVE
DEVELOPMENT.

HOWEVER...LATEST OBJECTIVE ANALYSIS SUGGESTS SOME WEAKENING OF
INHIBITION ACROSS SOUTHWEST ARKANSAS...JUST EAST OF SURFACE LOW...
WHERE LOW-LEVEL CONVERGENCE IS FOCUSED AND SURFACE DEW POINTS ARE
CLIMBING INTO THE MID/UPPER 60S.  MIXED LAYER CAPE IS INCREASING IN
EXCESS OF 1000 J/KG...AND BY 21-22Z AT LEAST ISOLATED STORMS APPEAR
POSSIBLE.  IF CONVECTION DEVELOPS...STRONG SHEAR PROFILES SHOULD
SUPPORT QUICK EVOLUTION OF SUPERCELLS...WITH POTENTIAL FOR VERY
LARGE HAIL.  DAMAGING WIND GUSTS AND ISOLATED TORNADOES WILL ALSO BE
POSSIBLE...AS ACTIVITY DEVELOPS EASTWARD THROUGH THE REMAINDER OF
THE AFTERNOON.

..KERR.. 04/29/2005

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

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

34049425 34219390 34289268 34399214 34099156 33539197
33129264 32759335 32719390 33189453

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Apr 28, 7:39 PM CDTMesoscale DiscussionSPCBaxter, Benton, Boone, Carroll, Cleburne, Conway and 21 more96 min
Apr 28, 9:51 PM CDTMesoscale DiscussionSPCBaxter, Clay, Cleburne, Craighead, Fulton, Greene and 11 more84 min
Apr 29, 4:36 AM CDTMesoscale DiscussionSPCBaxter, Benton, Boone, Carroll, Cleburne, Crawford and 15 more114 min
Apr 29, 6:20 AM CDTSevere Thunderstorm WatchSPCBaxter, Benton, Boone, Carroll, Clay, Cleburne and 30 more7 hr
Apr 29, 9:34 AM CDTMesoscale DiscussionSPCConway, Crittenden, Cross, Faulkner, Lee, Logan and 12 more116 min
Apr 29, 12:25 PM CDTMesoscale DiscussionSPCCleburne, Conway, Craighead, Crittenden, Cross, Faulkner and 19 more35 min
Apr 29, 12:50 PM CDTSevere Thunderstorm WatchSPCCleburne, Conway, Craighead, Crittenden, Cross, Faulkner and 23 more6 hr
Apr 29, 3:35 PM CDTTornado WatchSPCArkansas, Ashley, Bradley, Calhoun, Chicot, Clark and 19 more7 hr
Apr 29, 3:40 PM CDTMesoscale DiscussionSPCCleburne, Conway, Craighead, Crittenden, Cross, Faulkner and 11 more2 hr
Apr 29, 6:04 PM CDTMesoscale DiscussionSPCCraighead, Crittenden, Cross, Lee, Mississippi, Poinsett and 1 more56 min
Apr 29, 6:29 PM CDTMesoscale DiscussionSPCArkansas, Ashley, Bradley, Calhoun, Chicot, Clark and 16 more91 min
Apr 29, 4:10 PM CDTMesoscale DiscussionSPCAnderson, Bastrop, Brazos, Burleson, Caldwell, Cherokee and 15 more2 hr

Nearby

Mesoscale Discussions in Arkansas, 2005Mesoscale Discussions in Texas, 2005Every mesoscale discussion 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.