Alert archive / Texas / Mesoscale Discussions in 2012

Mesoscale Discussion 717

May 5, 201227 counties in Texas

The Storm Prediction Center issued this mesoscale discussion at May 5, 2012, 4:44 PM CDT for 27 counties in Texas. It was in force for 61 min.

The area

The outline as issued.

The facts

Issued: May 5, 2012, 4:44 PM CDT (21:44 UTC)
Expired: May 5, 2012, 5:45 PM CDT
In force: 61 min
Issued by: the Storm Prediction Center
Chance of a watch: 60%

All 27 counties

Bosque County, TX, Brown County, TX, Burnet County, TX, Callahan County, TX, Coleman County, TX, Comanche County, TX, Concho County, TX, Coryell County, TX, Eastland County, TX, Erath County, TX, Gillespie County, TX, Hamilton County, TX, Hood County, TX, Jack County, TX, Kimble County, TX, Lampasas County, TX, Llano County, TX, Mason County, TX, McCulloch County, TX, Menard County, TX, Mills County, TX, Palo Pinto County, TX, Parker County, TX, San Saba County, TX, Somervell County, TX, Stephens County, TX, Young County, TX

The radar

The Dyess AFB radar (KDYX), 111 km from the middle of the area, began a volume at 21:42 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 250May 5, 5:05 PM CDT

The nearest sounding before it

Fort Worth, TX (KFWD), launched 12:00Z, 9.7 hours before the alert went out and 202 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: 501 J/kg
Mixed-layer CIN: -544 J/kg
Mixed-layer LCL: 1641 m above ground
0-6 km bulk shear: 22 kt
0-1 km storm-relative helicity: 82 m²/s²
0-3 km storm-relative helicity: 227 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.

198 
ACUS11 KWNS 052145
SWOMCD
SPC MCD 052144
TXZ000-052245-

MESOSCALE DISCUSSION 0717
NWS STORM PREDICTION CENTER NORMAN OK
0444 PM CDT SAT MAY 05 2012

AREAS AFFECTED...CNTRL TX

CONCERNING...SEVERE POTENTIAL...WATCH POSSIBLE

VALID 052144Z - 052245Z

PROBABILITY OF WATCH ISSUANCE...60 PERCENT

SUMMARY...ISOLATED DRYLINE THUNDERSTORMS MAY BEGIN TO DEVELOP OVER
THE NEXT HOUR OR TWO OVER CNTRL TX...PROGRESSING EWD WITH TIME. A WW
MAY NEED TO BE ISSUED. LARGE HAIL AND DMGG WINDS WILL BE THE PRIMARY
THREATS.

DISCUSSION...2130Z VISIBLE IMAGERY REFLECTS AN INCREASING CU FIELD
ALONG THE DRYLINE...PARTICULARLY EAST OF SJT WHERE RADAR
REFLECTIVITY IS BEGINNING TO INCREASE IN CONCHO COUNTY. HOWEVER...NO
NOTABLE UPPER FEATURE IS EVIDENT THAT WOULD PROVIDE FORCING FOR
ASCENT...WITH WV IMAGERY AND PROFILER DATA GENERALLY IMPLYING
ANTICYCLONIC FLOW ALOFT...POSSIBLY SUPPRESSING MORE WIDESPREAD
POTENTIAL FOR THUNDERSTORM DEVELOPMENT. REGARDLESS...SFCOA INDICATES
NO CONVECTIVE INHIBITION REMAINING. CONVERGENCE ALONG THE DRYLINE
AND EXTREME INSTABILITY MAY BE SUFFICIENT TO OVERCOME SOMEWHAT
HOSTILE CONDITIONS ALOFT. VIGOROUS UPDRAFTS CAN BE EXPECTED IN
STORMS THAT CAN BECOME SUSTAINED...WITH LARGE HAIL AND DMGG WINDS
LIKELY. BRIEF SUPERCELLULAR STRUCTURES MAY BE POSSIBLE GIVEN VERY
SUBTLE LOW-MID LEVEL VEERING...THOUGH GENERALLY WEAK FLOW ALOFT
SHOULD LIMIT GREATER ORGANIZATION.

..HURLBUT.. 05/05/2012

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

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

LAT...LON   30460022 32309949 33039906 33309834 33059771 32249742
            30899791 30199866 30039967 30460022

SPC that day

Everything else SPC issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
May 4, 7:28 PM CDT	Mesoscale Discussion	SPC	Archer, Bosque, Brown, Callahan, Clay, Coleman and 21 more	62 min
May 4, 9:53 PM CDT	Mesoscale Discussion	SPC	Bosque, Collin, Dallas, Ellis, Grayson, Hamilton and 6 more	67 min
May 5, 5:02 PM CDT	Severe Thunderstorm Watch	SPC	Blanco, Brown, Burnet, Coleman, Comanche, Concho and 11 more	5 hr
May 5, 6:09 PM CDT	Mesoscale Discussion	SPC	Atascosa, La Salle, Live Oak, McMullen	66 min

Nearby

Mesoscale Discussions in Texas, 2012 Every mesoscale discussion in 2012

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.