Alert archive / Texas / Mesoscale Discussions in 2015

Mesoscale Discussion 577

May 9, 201518 counties in Texas

The Storm Prediction Center issued this mesoscale discussion at May 9, 2015, 9:38 PM CDT for 18 counties in Texas. It was in force for 2 hr.

The area

The outline as issued.

The facts

Issued: May 9, 2015, 9:38 PM CDT (02:38 UTC)
Expired: May 9, 2015, 11:45 PM CDT
In force: 2 hr
Issued by: the Storm Prediction Center
Chance of a watch: 60%

Counties Brown County, TX, Callahan County, TX, Coke County, TX, Coleman County, TX, Comanche County, TX, Concho County, TX, Crockett County, TX, Eastland County, TX, Erath County, TX, Irion County, TX, Menard County, TX, Reagan County, TX, Runnels County, TX, Schleicher County, TX, Sutton County, TX, Taylor County, TX, Terrell County, TX, Tom Green County, TX

The radar

The San Angelo radar (KSJT), 3 km from the middle of the area, began a volume at 02:40 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 152May 9, 10:45 PM CDT

The nearest sounding before it

Midland Regional, TX (KMAF), launched 00:00Z, 2.6 hours before the alert went out and 174 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: 0 J/kg
Mixed-layer CIN: No buoyant parcel
Mixed-layer LCL: 3886 m above ground
0-6 km bulk shear: 51 kt
0-1 km storm-relative helicity: 13 m²/s²
0-3 km storm-relative helicity: 44 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.

656 
ACUS11 KWNS 100238
SWOMCD
SPC MCD 100238 
TXZ000-100445-

MESOSCALE DISCUSSION 0577
NWS STORM PREDICTION CENTER NORMAN OK
0938 PM CDT SAT MAY 09 2015

AREAS AFFECTED...PORTION OF WRN TO CNTRL TX

CONCERNING...SEVERE POTENTIAL...WATCH POSSIBLE 

VALID 100238Z - 100445Z

PROBABILITY OF WATCH ISSUANCE...60 PERCENT

SUMMARY...SCATTERED TO NUMEROUS TSTMS ARE LIKELY TO DEVELOP THROUGH
MIDNIGHT AS THE PACIFIC COLD FRONT IMPINGES ON THE RETREATING
DRYLINE OVER THE ERN PERMIAN BASIN AND CONCHO VALLEY. LARGE HAIL
SHOULD BE THE PRIMARY HAZARD. POTENTIAL WW ISSUANCE MAY ALSO INCLUDE
REPLACING PORTIONS OF EXTENDED WW 149 THAT EXPIRES AT 04Z.

DISCUSSION...02Z SURFACE ANALYSIS PLACED THE RETREATING DRYLINE FROM
BREWSTER COUNTY TO NEAR SJT AND ABI. A SURGE OF NWLY SURFACE WINDS
HAS REACHED HOWARD TO PECOS COUNTY BEHIND A WEAK PACIFIC COLD FRONT.
IR SATELLITE IMAGERY CONFIRM INITIAL CONVECTIVE DEVELOPMENT OVER
PECOS COUNTY. WITH 40-KT LOW-LEVEL SELYS SAMPLED IN KDFX VWP
DATA...CONTINUED MOIST ADVECTION FROM THE EDWARDS PLATEAU/BIG
COUNTRY/LOWER RIO GRANDE VALLEY IN CONJUNCTION WITH CONVERGENCE
ALONG THE FRONT SHOULD RESULT IN DEEP CONVECTION BLOSSOMING THROUGH
MIDNIGHT. STEEP MID-LEVEL LAPSE RATES AND STRONG EFFECTIVE SHEAR
WILL FAVOR LARGE HAIL PRODUCTION...SOME OF WHICH MAY BE SIGNIFICANT
ESPECIALLY IN THE FIRST HOUR OR TWO AFTER INITIATION.
CONVECTION-ALLOWING GUIDANCE REMAINS QUITE CONSISTENT IN DEPICTING
RAPID CLUSTERING MODE WITH UPDRAFTS LIKELY GETTING UNDERCUT BY
COMPOSITE FRONT/OUTFLOW. THIS SHOULD TEND TO TEMPER THE OVERALL
SEVERE RISK OVERNIGHT.

..GRAMS/MEAD.. 05/10/2015

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

ATTN...WFO...FWD...EWX...SJT...MAF...

LAT...LON   30640240 31210180 31800113 32090052 32519994 32599929
            32469857 32209811 31939831 31559900 30859979 30140128
            30070215 30270244 30640240

SPC that day

Everything else SPC issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
May 9, 7:49 PM CDT	Mesoscale Discussion	SPC	Collin, Cooke, Dallas, Delta, Denton, Eastland and 17 more	56 min
May 9, 8:06 PM CDT	Mesoscale Discussion	SPC	Dimmit, Frio, Kinney, La Salle, Maverick, Uvalde and 2 more	84 min
May 9, 10:51 PM CDT	Severe Thunderstorm Watch	SPC	Bosque, Brown, Callahan, Coke, Coleman, Comanche and 33 more	10 hr
May 10, 2:06 AM CDT	Mesoscale Discussion	SPC	Brown, Callahan, Coleman, Concho, Crockett, Irion and 6 more	54 min
May 10, 2:55 AM CDT	Severe Thunderstorm Watch	SPC	Bosque, Collin, Comanche, Coryell, Dallas, Denton and 22 more	6 hr
May 10, 4:20 AM CDT	Mesoscale Discussion	SPC	Archer, Baylor, Brown, Clay, Collin, Comanche and 28 more	55 min
May 10, 6:44 AM CDT	Mesoscale Discussion	SPC	Bowie, Camp, Collin, Dallas, Delta, Denton and 15 more	2 hr
May 10, 9:28 AM CDT	Tornado Watch	SPC	Bowie, Red River	6 hr
May 10, 9:49 AM CDT	Mesoscale Discussion	SPC	Bell, Blanco, Bosque, Brown, Burnet, Camp and 49 more	2 hr
May 10, 10:19 AM CDT	Tornado Watch	SPC	Anderson, Bandera, Bell, Blanco, Bosque, Bowie and 68 more	13 hr
May 10, 12:33 PM CDT	Mesoscale Discussion	SPC	Archer, Clay, Montague	2 hr
May 10, 2:42 PM CDT	Mesoscale Discussion	SPC	Bandera, Bell, Blanco, Bosque, Bowie, Brown and 58 more	2 hr
May 10, 6:15 PM CDT	Mesoscale Discussion	SPC	Bell, Bowie, Burnet, Camp, Cass, Collin and 33 more	90 min

Nearby

Mesoscale Discussions in Texas, 2015 Every mesoscale discussion in 2015

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.