Alert archive / Texas / Mesoscale Discussions in 2012

Mesoscale Discussion 705

May 4, 201212 counties in Texas

The Storm Prediction Center issued this mesoscale discussion at May 4, 2012, 9:53 PM CDT for 12 counties in Texas. It was in force for 67 min.

The area

The outline as issued.

The facts

Issued
May 4, 2012, 9:53 PM CDT (02:53 UTC)
Expired
May 4, 2012, 11:00 PM CDT
In force
67 min
Issued by
the Storm Prediction Center

Counties Bosque County, TX, Collin County, TX, Dallas County, TX, Ellis County, TX, Grayson County, TX, Hamilton County, TX, Hill County, TX, Johnson County, TX, Mills County, TX, Rockwall County, TX, Somervell County, TX, Tarrant County, TX

The radar

The Dallas/Ft Worth radar (KFWS), 7 km from the middle of the area, began a volume at 02:54 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 00:00Z, 2.9 hours before the alert went out and 23 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 00:00Z on 2012-05-05Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 2627 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 00:00Z on 2012-05-05The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 41 square meters per square second.193958Sfc1 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
2627 J/kg
Mixed-layer CIN
-48 J/kg
Mixed-layer LCL
1899 m above ground
0-6 km bulk shear
35 kt
0-1 km storm-relative helicity
41 m²/s²
0-3 km storm-relative helicity
117 m²/s²
Significant tornado parameter
0.1
Supercell composite
7.1

Open this sounding in Storm Lab

The text

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

741 
ACUS11 KWNS 050253
SWOMCD
SPC MCD 050253 
TXZ000-050400-

MESOSCALE DISCUSSION 0705
NWS STORM PREDICTION CENTER NORMAN OK
0953 PM CDT FRI MAY 04 2012

AREAS AFFECTED...CNTRL TX

CONCERNING...SEVERE THUNDERSTORM WATCH 240...

VALID 050253Z - 050400Z

THE SEVERE WEATHER THREAT FOR SEVERE THUNDERSTORM WATCH 240
CONTINUES.

SUMMARY...THUNDERSTORMS CAPABLE OF DMGG WINDS AND LARGE HAIL ARE
GRADUALLY DIMINISHING IN COVERAGE. THE WW WILL BE ALLOWED TO EXPIRE
AT 04Z...THOUGH ISOLATED SEVERE MAY STILL OCCUR OVER THE NEXT FEW
HOURS. HOWEVER...COVERAGE IS EXPECTED TO BE INSUFFICIENT TO WARRANT
A NEW WW.

DISCUSSION...THE WRN PORTION OF THE WW CONTINUES TO STABILIZE IN THE
WAKE OF CONVECTIVE PRECIPITATION...AND AS DIURNAL COOLING BEGINS.
DOWNSTREAM OF THE ONGOING CONVECTION...MODERATE INSTABILITY IS
PERSISTING...WITH A NOW CLEARLY EVIDENT /PARTIALLY CONVECTIVELY
INDUCED/ VORT MAX SEEMING TO MAINTAIN A CLUSTER OF STORMS OVER N
CNTRL TX. WITH OUTFLOW UNDERCUTTING THE STORMS AND SURGING WELL OUT
AHEAD...AND THE ONSET OF DIURNAL COOLING...EXPECT A GRADUAL
WEAKENING TREND OVER THE NEXT FEW HOURS.

..HURLBUT.. 05/05/2012

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

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

LAT...LON   33849696 33659635 33029612 32039660 31679738 31409818
            31379876 31739898 32329773 33169710 33509698 33849696

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
May 4, 7:28 PM CDTMesoscale DiscussionSPCArcher, Bosque, Brown, Callahan, Clay, Coleman and 21 more62 min
May 5, 4:44 PM CDTMesoscale DiscussionSPCBosque, Brown, Burnet, Callahan, Coleman, Comanche and 21 more61 min
May 5, 5:02 PM CDTSevere Thunderstorm WatchSPCBlanco, Brown, Burnet, Coleman, Comanche, Concho and 11 more5 hr
May 5, 6:09 PM CDTMesoscale DiscussionSPCAtascosa, La Salle, Live Oak, McMullen66 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.