Alert archive / Texas / Mesoscale Discussions in 2012

Mesoscale Discussion 1745

August 12, 2012Bryan County, Johnston County, Marshall County, Oklahoma; 15 counties in Texas

The Storm Prediction Center issued this mesoscale discussion at Aug 12, 2012, 6:06 PM CDT for Bryan County, Johnston County, Marshall County, Oklahoma; 15 counties in Texas. It was in force for 54 min.

The area

The outline as issued.

The facts

Issued
Aug 12, 2012, 6:06 PM CDT (23:06 UTC)
Expired
Aug 12, 2012, 7:00 PM CDT
In force
54 min
Issued by
the Storm Prediction Center

Counties Bryan County, OK, Johnston County, OK, Marshall County, OK, Cooke County, TX, Denton County, TX, Fisher County, TX, Grayson County, TX, Jack County, TX, Jones County, TX, Nolan County, TX, Palo Pinto County, TX, Parker County, TX, Shackelford County, TX, Stephens County, TX, Taylor County, TX, Throckmorton County, TX, Wise County, TX, Young County, TX

The radar

The Dallas/Ft Worth radar (KFWS), 102 km from the middle of the area, began a volume at 23:08 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, 11.1 hours before the alert went out and 83 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 2012-08-12Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 792 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 2012-08-12The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 17 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
792 J/kg
Mixed-layer CIN
-434 J/kg
Mixed-layer LCL
1708 m above ground
0-6 km bulk shear
18 kt
0-1 km storm-relative helicity
17 m²/s²
0-3 km storm-relative helicity
146 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.

304 
ACUS11 KWNS 122306
SWOMCD
SPC MCD 122306 
OKZ000-TXZ000-130000-

MESOSCALE DISCUSSION 1745
NWS STORM PREDICTION CENTER NORMAN OK
0606 PM CDT SUN AUG 12 2012

AREAS AFFECTED...N CNTRL TX

CONCERNING...SEVERE THUNDERSTORM WATCH 573...

VALID 122306Z - 130000Z

THE SEVERE WEATHER THREAT FOR SEVERE THUNDERSTORM WATCH 573
CONTINUES.

SUMMARY...THUNDERSTORMS CAPABLE OF DMGG WINDS WILL CONTINUE TO
DEVELOP AND SLOWLY PROGRESS ESEWD WITH TIME. A NEW WW IS BEING
CONSIDERED ACROSS ERN OK...NERN TX...SERN KS...NWRN AR AND SWRN MO.
ADDITIONAL STORMS APPEAR TO BE DEVELOPING ACROSS S CNTRL OK.

DISCUSSION...SEVERE THUNDERSTORMS HAVE DEVELOPED ALONG A WEAK SW-NE
ORIENTED COLD FRONT/WIND SHIFT EXTENDING ROUGHLY FROM JUST N OF MAF
NEWD INTO SERN OK. ERN MOST STORMS APPEAR TO BETTER SUSTAINED AMIDST
A WEAK LOW-LEVEL WARM ADVECTION REGIME BENEATH NWLY FLOW ALOFT.
VEERING WINDS WITH INCREASING HEIGHT CONFIRMED BY AREA VAD WIND
PROFILE DATA...AND GREATER MOISTURE /PREDOMINANTLY ABOVE 700 MB/
COMPARED TO AREAS WWD IS LIKELY CONTRIBUTING TO SUSTAINED UPDRAFTS.
A WELL-MIXED BOUNDARY LAYER/STEEP LOW LEVEL LAPSE RATES OWING TO
DIURNAL HEATING /SURFACE TEMPERATURES NEAR 102 TO 104 F AND LOWER
60S F DEW POINTS/ WILL SUPPORT DMGG WIND POTENTIAL AS EVAPORATIVE
COOLING AND PRECIPITATION LOADING ENSUE.

..HURLBUT.. 08/12/2012

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

ATTN...WFO...FWD...OUN...SJT...LUB...MAF...

LAT...LON   33709742 34459678 34259616 33579613 32999693 32529801
            32289968 32250056 32720077 33569818 33709742

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Aug 12, 3:29 PM CDTMesoscale DiscussionSPCAtoka, Bryan, Carter, Choctaw, Coal, Garvin and 7 more31 min
Aug 12, 3:55 PM CDTSevere Thunderstorm WatchSPCAtoka, Bryan, Carter, Coal, Jefferson, Johnston and 4 more7 hr
Aug 12, 6:28 PM CDTMesoscale DiscussionSPCAdair, Cherokee, Choctaw, Craig, Delaware, Haskell and 15 more92 min

Nearby

Mesoscale Discussions in Texas, 2012Mesoscale Discussions in Oklahoma, 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.