Alert archive / Texas / Mesoscale Discussions in 2012

Mesoscale Discussion 720

May 5, 20124 counties in Texas

The Storm Prediction Center issued this mesoscale discussion at May 5, 2012, 6:09 PM CDT for 4 counties in Texas. It was in force for 66 min.

The area

The outline as issued.

The facts

Issued: May 5, 2012, 6:09 PM CDT (23:09 UTC)
Expired: May 5, 2012, 7:15 PM CDT
In force: 66 min
Issued by: the Storm Prediction Center
Chance of a watch: 20%

Counties Atascosa County, TX, La Salle County, TX, Live Oak County, TX, McMullen County, TX

The radar

The Corpus Christi radar (KCRP), 129 km from the middle of the area, began a volume at 23:11 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

Corpus Christi, TX (KCRP), launched 12:00Z, 11.2 hours before the alert went out and 145 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: 1396 J/kg
Mixed-layer CIN: -259 J/kg
Mixed-layer LCL: 941 m above ground
0-6 km bulk shear: 15 kt
0-1 km storm-relative helicity: 78 m²/s²
0-3 km storm-relative helicity: 123 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.

482 
ACUS11 KWNS 052309
SWOMCD
SPC MCD 052309 
TXZ000-060015-

MESOSCALE DISCUSSION 0720
NWS STORM PREDICTION CENTER NORMAN OK
0609 PM CDT SAT MAY 05 2012

AREAS AFFECTED...S TX

CONCERNING...SEVERE POTENTIAL...WATCH UNLIKELY 

VALID 052309Z - 060015Z

PROBABILITY OF WATCH ISSUANCE...20 PERCENT

SUMMARY...ISOLATED SEVERE THUNDERSTORMS ARE POSSIBLE OVER PORTIONS
OF S TX. ATTM...COVERAGE APPEARS TO BE INSUFFICIENT TO WARRANT A
WW...BUT TRENDS WILL CONTINUE TO BE MONITORED.

DISCUSSION...ISOLATED THUNDERSTORMS HAVE DEVELOPED IN AN AREA OF
WEAK SURFACE CONFLUENCE...WHERE A SUBTLE MOISTURE GRADIENT EXISTS. A
WEAK UPPER WAVE NOTED ON WV IMAGERY APPROACHING S TX MAY ALSO BE
PROVIDING SUBTLE FORCING FOR ASCENT. EXTREME INSTABILITY MAY SUPPORT
VIGOROUS UPDRAFTS IN STORMS THAT CAN BECOME SUSTAINED...THOUGH A
LACK OF STRONGER WINDS ALOFT WILL LIKELY LIMIT GREATER ORGANIZATION.
ADDITIONALLY...CONVECTIVE INHIBITION IS STRONGER CLOSER TO THE
COAST...SO ONGOING STORMS MAY PROGRESS INTO AN INCREASINGLY
UNSUPPORTIVE ENVIRONMENT...LIMITING THE SPATIOTEMPORAL THREAT
FURTHER.

..HURLBUT.. 05/05/2012

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

ATTN...WFO...CRP...EWX...

LAT...LON   29129806 28769787 28279811 27919860 27769916 28399930
            29299858 29129806

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, 4:44 PM CDT	Mesoscale Discussion	SPC	Bosque, Brown, Burnet, Callahan, Coleman, Comanche and 21 more	61 min
May 5, 5:02 PM CDT	Severe Thunderstorm Watch	SPC	Blanco, Brown, Burnet, Coleman, Comanche, Concho and 11 more	5 hr

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.