Alert archive / Texas / Mesoscale Discussions in 2012

Mesoscale Discussion 475

April 7, 20124 counties in Texas

The Storm Prediction Center issued this mesoscale discussion at Apr 7, 2012, 9:53 PM CDT for 4 counties in Texas. It was in force for 97 min.

The area

The outline as issued.

The facts

Issued
Apr 7, 2012, 9:53 PM CDT (02:53 UTC)
Expired
Apr 7, 2012, 11:30 PM CDT
In force
97 min
Issued by
the Storm Prediction Center

Counties Crockett County, TX, Schleicher County, TX, Sutton County, TX, Terrell County, TX

The nearest sounding before it

Midland Regional, TX (KMAF), launched 00:00Z, 2.9 hours before the alert went out and 148 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, Midland Regional, TX at 00:00Z on 2012-04-08Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 190 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, Midland Regional, TX at 00:00Z on 2012-04-08The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity -40 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
190 J/kg
Mixed-layer CIN
-57 J/kg
Mixed-layer LCL
3049 m above ground
0-6 km bulk shear
28 kt
0-1 km storm-relative helicity
-40 m²/s²
0-3 km storm-relative helicity
113 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.6

Open this sounding in Storm Lab

The text

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

628 
ACUS11 KWNS 080254
SWOMCD
SPC MCD 080253
TXZ000-080430-

MESOSCALE DISCUSSION 0475
NWS STORM PREDICTION CENTER NORMAN OK
0953 PM CDT SAT APR 07 2012

AREAS AFFECTED...EDWARDS PLATEAU OF SWRN TX

CONCERNING...SEVERE THUNDERSTORM WATCH 150...

VALID 080253Z - 080430Z

THE SEVERE WEATHER THREAT FOR SEVERE THUNDERSTORM WATCH 150
CONTINUES.

A SLOW MOVING MCS HAS EVOLVED ALONG COLD FRONT AS IT PROGRESSES SWD
ACROSS THE EDWARDS PLATEAU.  00Z SOUNDINGS ACROSS THIS REGION
EXHIBITED STEEP LOW LEVEL LAPSE RATES BUT ALSO DISPLAYED ONLY
MARGINAL DEEP LAYER SHEAR.  IN THE ABSENCE OF STRONG SHEAR...THE MCS
APPEARS TO BE THRIVING ON FRONTAL CONVERGENCE...ENHANCED BY
EXPANDING POST-FRONTAL PRECIP...AND YET TO BE OVERTURNED INSTABILITY
ACROSS SWRN TX.  LATEST RADAR IMAGERY SUGGESTS THE OVERALL MCS IS
PROPAGATING SWD AT 10-20KT AND COULD APPROACH THE MEXICAN BORDER
LATER TONIGHT.  IN ADDITION TO HEAVY RAIN LARGE HAIL REMAINS THE
GREATEST SEVERE THREAT WITH THIS ACTIVITY AND PORTIONS OF WW150 WILL
BE EXTENDED IN TIME TO ACCOUNT FOR THIS EVOLUTION.

..DARROW.. 04/08/2012

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

ATTN...WFO...EWX...SJT...MAF...

LAT...LON   31140239 31180017 30260024 30130216 31140239

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Apr 8, 1:27 PM CDTMesoscale DiscussionSPCDallas, Ellis, Henderson, Kaufman, Navarro, Rockwall93 min
Apr 8, 5:48 PM CDTMesoscale DiscussionSPCAnderson, Cherokee, Freestone, Henderson, Houston, Leon and 3 more117 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.