Alert archive / Texas / Mesoscale Discussions in 2016

Mesoscale Discussion 490

April 29, 201617 counties in Arkansas; 20 counties in Oklahoma; 23 counties in Texas

The Storm Prediction Center issued this mesoscale discussion at Apr 29, 2016, 1:58 AM CDT for 17 counties in Arkansas; 20 counties in Oklahoma; 23 counties in Texas. It was in force for 2 hr.

The area

The outline as issued.

The facts

Issued
Apr 29, 2016, 1:58 AM CDT (06:58 UTC)
Expired
Apr 29, 2016, 4:00 AM CDT
In force
2 hr
Issued by
the Storm Prediction Center
Chance of a watch
60%
All 60 counties

Clark County, AR, Columbia County, AR, Dallas County, AR, Garland County, AR, Hempstead County, AR, Hot Spring County, AR, Howard County, AR, Lafayette County, AR, Little River County, AR, Miller County, AR, Montgomery County, AR, Nevada County, AR, Ouachita County, AR, Pike County, AR, Polk County, AR, Scott County, AR, Sevier County, AR, Atoka County, OK, Bryan County, OK, Carter County, OK, Choctaw County, OK, Coal County, OK, Garvin County, OK, Hughes County, OK, Jefferson County, OK, Johnston County, OK, Latimer County, OK, LeFlore County, OK, Love County, OK, Marshall County, OK, McCurtain County, OK, Murray County, OK, Pittsburg County, OK, Pontotoc County, OK, Pushmataha County, OK, Seminole County, OK, Stephens County, OK, Bowie County, TX, Camp County, TX, Cass County, TX, Collin County, TX, Cooke County, TX, Delta County, TX, Denton County, TX, Fannin County, TX, Franklin County, TX, Grayson County, TX, Hopkins County, TX, Hunt County, TX, Lamar County, TX, Marion County, TX, Montague County, TX, Morris County, TX, Rains County, TX, Red River County, TX, Rockwall County, TX, Titus County, TX, Upshur County, TX, Wise County, TX, Wood County, TX

The radar

The Western Arkansas radar (KSRX), 182 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 watches that followed

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

The nearest sounding before it

Fort Worth, TX (KFWD), launched 00:00Z, 7.0 hours before the alert went out and 210 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, Fort Worth, TX at 00:00Z on 2016-04-29Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 14 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, Fort Worth, TX at 00:00Z on 2016-04-29The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 69 square meters per square second.193958Sfc1 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
14 J/kg
Mixed-layer CIN
-442 J/kg
Mixed-layer LCL
2160 m above ground
0-6 km bulk shear
42 kt
0-1 km storm-relative helicity
69 m²/s²
0-3 km storm-relative helicity
214 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.1

Open this sounding in Storm Lab

The text

As transmitted.

941 
ACUS11 KWNS 290658
SWOMCD
SPC MCD 290658 
ARZ000-LAZ000-TXZ000-OKZ000-290900-

MESOSCALE DISCUSSION 0490
NWS STORM PREDICTION CENTER NORMAN OK
0158 AM CDT FRI APR 29 2016

AREAS AFFECTED...SOUTHEAST OK...NORTHEAST TX...SOUTHWEST AR

CONCERNING...SEVERE POTENTIAL...WATCH POSSIBLE 

VALID 290658Z - 290900Z

PROBABILITY OF WATCH ISSUANCE...60 PERCENT

SUMMARY...ISOLATED SEVERE HAIL MAY OCCUR FOR THE NEXT SEVERAL
HOURS...WITH A POTENTIAL INCREASE RISK IN ALL HAZARDS OCCURRING
AFTER 09Z.

DISCUSSION...06Z SURFACE ANALYSIS PLACED A ROBUST WARM FRONT ACROSS
NORTH-CENTRAL/NORTHEAST TX INTO NORTH LA. LOW-LEVEL WAA IS
SUPPORTING A SUBSTANTIAL INCREASE IN STORM COVERAGE N OF THIS
BOUNDARY ALONG THE RED RIVER TO ARKLATEX REGION. GPS PW DATA HAVE
SAMPLED A RAPID INCREASE IN VALUES ALONG AND SOUTH OF THE FRONT WITH
LOWER TO MIDDLE 70S SURFACE DEW POINTS COMMON WITHIN THE MARITIME
TROPICAL AIR MASS. MOST GUIDANCE INDICATES STRENGTHENING OF THE
EASTERN BRANCH OF THE LOW-LEVEL JET WITH THE NOSE FOCUSED ON THE
ARKLATEX REGION BETWEEN 09-12Z. WHILE ALL CONVECTION WILL POSE A
RISK FOR ISOLATED SEVERE HAIL /LIKELY NO LARGER THAN GOLF BALLS
GIVEN PREDOMINANT CLUSTER MODE/...REGENERATIVE ACTIVITY MAY
EVENTUALLY TRANSITION TO SURFACE-BASED AS THE WARM FRONT ADVANCES
NORTH. WITHIN AN ELONGATED LOW-LEVEL HODOGRAPH...A COUPLE EMBEDDED
SUPERCELLS CAPABLE OF ALL HAZARDS COULD BECOME POSSIBLE TOWARDS 12Z.
HOWEVER...UNCERTAINTY DOES EXIST WHETHER THE STRENGTH OF THE
ELEVATED MIXED LAYER AND RELATED CAPPING INVERSION MAY MITIGATE TRUE
WARM SECTOR STORM SUSTENANCE.

..GRAMS/GOSS.. 04/29/2016

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

ATTN...WFO...LZK...SHV...TSA...FWD...OUN...

LAT...LON   34489793 35149729 35229576 34979386 34719302 34369269
            33869250 33279291 32909364 32669485 32709609 32849721
            33309794 33999814 34489793

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Apr 29, 4:21 AM CDTSevere Thunderstorm WatchSPCArkansas, Clark, Cleveland, Conway, Crawford, Dallas and 25 more6 hr
Apr 29, 7:06 AM CDTMesoscale DiscussionSPCArkansas, Bradley, Calhoun, Clark, Cleveland, Dallas and 5 more54 min
Apr 29, 9:46 AM CDTMesoscale DiscussionSPCArkansas, Ashley, Bradley, Calhoun, Chicot, Clark and 29 more89 min
Apr 29, 12:51 PM CDTMesoscale DiscussionSPCBradley, Calhoun, Clark, Columbia, Hempstead, Howard and 8 more114 min
Apr 29, 1:43 PM CDTTornado WatchSPCBradley, Calhoun, Clark, Cleveland, Columbia, Dallas and 10 more8 hr
Apr 29, 5:42 PM CDTMesoscale DiscussionSPCBradley, Calhoun, Clark, Cleveland, Columbia, Dallas and 11 more93 min
Apr 28, 10:54 PM CDTSevere Thunderstorm WatchSPCBeaver, Cimarron, Texas7 hr
Apr 29, 2:59 AM CDTMesoscale DiscussionSPCBeaver, Ellis, Harper91 min
Apr 29, 4:54 AM CDTMesoscale DiscussionSPCHarmon66 min
Apr 29, 1:40 PM CDTMesoscale DiscussionSPCAtoka, Bryan, Carter, Cleveland, Coal, Comanche and 15 more65 min
Apr 29, 1:57 PM CDTTornado WatchSPCAtoka, Bryan, Caddo, Canadian, Carter, Choctaw and 27 more8 hr
Apr 29, 3:56 PM CDTMesoscale DiscussionSPCAtoka, Bryan, Caddo, Carter, Cleveland, Coal and 18 more64 min
Apr 29, 6:16 PM CDTMesoscale DiscussionSPCAdair, Atoka, Bryan, Carter, Cherokee, Choctaw and 25 more89 min
Apr 28, 7:52 PM CDTMesoscale DiscussionSPCBell, Brazos, Burleson, Burnet, Coryell, Falls and 7 more83 min
Apr 28, 10:31 PM CDTMesoscale DiscussionSPCArmstrong, Bailey, Briscoe, Carson, Castro, Childress and 30 more89 min
Apr 29, 7:38 AM CDTMesoscale DiscussionSPCBriscoe, Cottle, Crosby, Dickens, Floyd, Foard and 10 more97 min
Apr 29, 12:52 PM CDTMesoscale DiscussionSPCBell, Blanco, Bosque, Brown, Burnet, Comanche and 22 more113 min
Apr 29, 1:08 PM CDTTornado WatchSPCAnderson, Bell, Bosque, Collin, Comanche, Cooke and 35 more9 hr
Apr 29, 3:34 PM CDTMesoscale DiscussionSPCBell, Bosque, Collin, Cooke, Coryell, Dallas and 31 more86 min

Nearby

Mesoscale Discussions in Texas, 2016Mesoscale Discussions in Oklahoma, 2016Mesoscale Discussions in Arkansas, 2016Every mesoscale discussion in 2016

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.