Alert archive / Texas / Mesoscale Discussions in 2011

Mesoscale Discussion 779

May 13, 201122 counties in Texas

The Storm Prediction Center issued this mesoscale discussion at May 13, 2011, 4:55 PM CDT for 22 counties in Texas. It was in force for 95 min.

The area

The outline as issued.

The facts

Issued
May 13, 2011, 4:55 PM CDT (21:55 UTC)
Expired
May 13, 2011, 6:30 PM CDT
In force
95 min
Issued by
the Storm Prediction Center
All 22 counties

Atascosa County, TX, Bee County, TX, Brooks County, TX, Dimmit County, TX, Duval County, TX, Frio County, TX, Hidalgo County, TX, Jim Hogg County, TX, Jim Wells County, TX, Kenedy County, TX, Kleberg County, TX, La Salle County, TX, Live Oak County, TX, McMullen County, TX, Medina County, TX, Nueces County, TX, San Patricio County, TX, Starr County, TX, Webb County, TX, Willacy County, TX, Zapata County, TX, Zavala County, TX

The radar

The Corpus Christi radar (KCRP), 133 km from the middle of the area, began a volume at 21:59 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, 9.9 hours before the alert went out and 150 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, Corpus Christi, TX at 12:00Z on 2011-05-13Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 1748 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, Corpus Christi, TX at 12:00Z on 2011-05-13The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 44 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
1748 J/kg
Mixed-layer CIN
-124 J/kg
Mixed-layer LCL
593 m above ground
0-6 km bulk shear
27 kt
0-1 km storm-relative helicity
44 m²/s²
0-3 km storm-relative helicity
23 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.

439 
ACUS11 KWNS 132155
SWOMCD
SPC MCD 132155 
TXZ000-132330-

MESOSCALE DISCUSSION 0779
NWS STORM PREDICTION CENTER NORMAN OK
0455 PM CDT FRI MAY 13 2011

AREAS AFFECTED...SOUTH TX

CONCERNING...SEVERE POTENTIAL...WATCH POSSIBLE 

VALID 132155Z - 132330Z

AN ISOLATED SEVERE THREAT CANNOT BE RULED OUT ACROSS
SOUTH-CENTRAL/FAR SOUTH TX LATE THIS AFTERNOON/EARLY EVENING.

A FEW TSTMS HAVE RECENTLY DEVELOPED ACROSS SOUTH-CENTRAL TX NEAR THE
HONDO AREA JUST WEST OF SAN ANTONIO AS OF 2140Z....IN CLOSE
PROXIMITY TO THE SURFACE COLD FRONT...WITH ADDITIONAL DEVELOPMENT
ALSO NOTED ACROSS DEEP SOUTH TX TOWARD THE RIO GRANDE IN AREAS JUST
NORTH/NORTHWEST OF MCALLEN. WITH SURFACE TEMPERATURES IN THE 90S
F...A RELATIVELY HOT/MODESTLY MOIST AIRMASS IN PLACE ACROSS SOUTH
TX...WITH MLCAPE VALUES ESTIMATED TO RANGE FROM 1500-3500 J/KG
ACROSS THE WARM SECTOR. CURRENT THINKING IS THAT DEEP CONVECTIVE
DEVELOPMENT WILL REMAIN RELATIVELY ISOLATED IN NATURE IN THE
PRESENCE OF MODEST BACKGROUND FORCING FOR ASCENT...BUT AN ISOLATED
SEVERE THREAT CANNOT BE RULED OUT GIVEN STEEP LAPSE RATES/AMPLE
INSTABILITY IN CONJUNCTION WITH RELATIVELY STRONG MID/UPPER
TROPOSPHERIC FLOW.

..GUYER.. 05/13/2011

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

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

LAT...LON   29469929 29259824 27919701 26299763 26359892 27999985
            28820001 29469929

Nearby

Mesoscale Discussions in Texas, 2011Every mesoscale discussion in 2011

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.