Alert archive / Texas / Mesoscale Discussions in 2012

Mesoscale Discussion 737

May 6, 201227 counties in Texas

The Storm Prediction Center issued this mesoscale discussion at May 6, 2012, 5:15 PM CDT for 27 counties in Texas. It was in force for 60 min.

The area

The outline as issued.

The facts

Issued
May 6, 2012, 5:15 PM CDT (22:15 UTC)
Expired
May 6, 2012, 6:15 PM CDT
In force
60 min
Issued by
the Storm Prediction Center
Chance of a watch
20%
All 27 counties

Baylor County, TX, Brown County, TX, Burnet County, TX, Callahan County, TX, Coke County, TX, Coleman County, TX, Comanche County, TX, Concho County, TX, Eastland County, TX, Haskell County, TX, Irion County, TX, Jones County, TX, Lampasas County, TX, Llano County, TX, Mason County, TX, McCulloch County, TX, Menard County, TX, Mills County, TX, Runnels County, TX, San Saba County, TX, Schleicher County, TX, Shackelford County, TX, Stephens County, TX, Taylor County, TX, Throckmorton County, TX, Tom Green County, TX, Wilbarger County, TX

The radar

The Dyess AFB radar (KDYX), 60 km from the middle of the area, began a volume at 22:15 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

Fort Worth, TX (KFWD), launched 12:00Z, 10.3 hours before the alert went out and 214 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 12:00Z on 2012-05-06Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 1528 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 12:00Z on 2012-05-06The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 11 square meters per square second.1939Sfc1 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
1528 J/kg
Mixed-layer CIN
-387 J/kg
Mixed-layer LCL
1140 m above ground
0-6 km bulk shear
6 kt
0-1 km storm-relative helicity
11 m²/s²
0-3 km storm-relative helicity
71 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.1

Open this sounding in Storm Lab

The text

As transmitted, in the capitals the NWS used until 2016.

575 
ACUS11 KWNS 062215
SWOMCD
SPC MCD 062215 
TXZ000-OKZ000-062315-

MESOSCALE DISCUSSION 0737
NWS STORM PREDICTION CENTER NORMAN OK
0515 PM CDT SUN MAY 06 2012

AREAS AFFECTED...CNTRL TX

CONCERNING...SEVERE POTENTIAL...WATCH UNLIKELY 

VALID 062215Z - 062315Z

PROBABILITY OF WATCH ISSUANCE...20 PERCENT

SUMMARY...ISOLATED STORMS MAY FORM ALONG THE DRYLINE AND REMNANT
OUTFLOW BOUNDARIES ACROSS CNTRL TX. ALTHOUGH DMGG WINDS AND HAIL MAY
BE POSSIBLE...COVERAGE WILL LIKELY BE INSUFFICIENT TO WARRANT A WW.

DISCUSSION...12Z SOUNDINGS ACROSS THE TX/OK AREA THIS MORNING SHOWED
A VERY SHALLOW MOIST LAYER JUST ABOVE THE SURFACE. AMPLE SURFACE
HEATING HAS GENERALLY RESULTED IN THE EROSION OF THIS LAYER...WITH A
WELL MIXED BOUNDARY LAYER AND MUCH LOWER DEW POINT VALUES MIXING TO
THE SURFACE. AS SUCH...ONLY WEAK MID-LEVEL INSTABILITY REMAINS
SURROUNDING THE DRYLINE. 22Z WV IMAGERY REFLECTS AN AREA OF IMPLIED
FORCING FOR ASCENT FROM WRN OK INTO SWRN TX...WHICH MAY BE
SUFFICIENT FOR INITIATION/CONTINUANCE OF A FEW STORMS ALONG THE
DRYLINE...WITH MARGINAL WIND AND HAIL POTENTIAL ASSOCIATED WITH
STORMS THAT CAN BECOME SUSTAINED. 

FARTHER EAST...YESTERDAY/S CONVECTION APPEARS TO HAVE LEFT TWO
REMNANT OUTFLOW BOUNDARIES OVER CNTRL TX...WHERE AN ISOLATED STORM
HAS FORMED IN LAMPASAS COUNTY. ALTHOUGH INSTABILITY IS GREATER IN
THIS AREA...COVERAGE MAY INITIALLY BE LIMITED AMIDST SHORT WAVE
RIDGING BETWEEN THE EXITING UPPER FEATURE OVER ERN TX AND THE
AFOREMENTIONED APPROACHING ONE. AS SUCH...ONLY A LIMITED TEMPORAL
THREAT MAY EXIST BEFORE NOCTURNAL COOLING BEGINS TO STABILIZE THE
AREA.

..HURLBUT/THOMPSON.. 05/06/2012

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

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

LAT...LON   34349902 33679872 33039873 32399877 31799839 31099777
            30719778 30499845 30329920 30579987 30820077 30580133
            30960134 31760075 33099981 34169925 34349902

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
May 5, 8:22 PM CDTMesoscale DiscussionSPCBlanco, Brown, Burnet, Coleman, Comanche, Concho and 11 more53 min
May 6, 6:05 PM CDTMesoscale DiscussionSPCAngelina, Austin, Cherokee, Grimes, Hardin, Harris and 16 more55 min

Nearby

Mesoscale Discussions in Texas, 2012Every 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.