Alert archive / Texas / Mesoscale Discussions in 2012

Mesoscale Discussion 477

April 8, 20129 counties in Texas

The Storm Prediction Center issued this mesoscale discussion at Apr 8, 2012, 5:48 PM CDT for 9 counties in Texas. It was in force for 117 min.

The area

The outline as issued.

The facts

Issued
Apr 8, 2012, 5:48 PM CDT (22:48 UTC)
Expired
Apr 8, 2012, 7:45 PM CDT
In force
117 min
Issued by
the Storm Prediction Center

Counties Anderson County, TX, Cherokee County, TX, Freestone County, TX, Henderson County, TX, Houston County, TX, Leon County, TX, Madison County, TX, Trinity County, TX, Walker County, TX

The radar

The Shreveport radar (KSHV), 188 km from the middle of the area, began a volume at 22:48 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

Shreveport, LA (KSHV), launched 12:00Z, 10.8 hours before the alert went out and 197 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, Shreveport, LA at 12:00Z on 2012-04-08Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 0 joules per kilogram.LCL10008507005003002001001 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, Shreveport, LA at 12:00Z on 2012-04-08The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity -4 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
0 J/kg
Mixed-layer CIN
No buoyant parcel
Mixed-layer LCL
1470 m above ground
0-6 km bulk shear
20 kt
0-1 km storm-relative helicity
-4 m²/s²
0-3 km storm-relative helicity
-7 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.

184 
ACUS11 KWNS 082249
SWOMCD
SPC MCD 082248
TXZ000-090045-

MESOSCALE DISCUSSION 0477
NWS STORM PREDICTION CENTER NORMAN OK
0548 PM CDT SUN APR 08 2012

AREAS AFFECTED...SE TX

CONCERNING...SEVERE POTENTIAL...WATCH UNLIKELY

VALID 082248Z - 090045Z

AN ISOLATED THREAT FOR HAIL AND STRONG WINDS WILL EXIST ACROSS SE TX
THIS EVENING. HOWEVER...ISOLATED/BRIEF NATURE OF THE THREAT
PRECLUDES THE ISSUANCE OF A WW.

ONGOING THUNDERSTORM ACTIVITY ACROSS N-CNTRL/CNTRL TX IS EXPECTED TO
CONTINUE FOR THE NEXT FEW HOURS. LATEST HRRR/RUC SOUNDINGS AND SFC
OBJECTIVE ANALYSIS INDICATES SBCAPE AOA 1000 J/KG AND EFFECTIVE
SHEAR AROUND 30 KTS AHEAD OF THE LINE OF STORMS. THE STRONGEST
STORMS ARE LOCATED IN AND AROUND ANDERSON COUNTY WHERE SURFACE
ANALYSIS INDICATES AN INTERSECTION OF A SWD PROGRESSING COLD FRONT
ASSOCIATED WITH HIGH PRESSURE OVER OK AND A STATIONARY BOUNDARY
RESULTANT FROM YESTERDAYS THUNDERSTORM ACTIVITY ACROSS W TX. AS A
RESULT...STRONGEST STORMS ARE EXPECTED TO REMAIN NEAR THIS
INTERSECTION WHICH WILL PROGRESS SLOWLY SEWD OVER THE NEXT FEW
HOURS. THE PRIMARY THREAT WITH THIS ACTIVITY IS EXPECTED TO BE LARGE
HAIL ALTHOUGH SOME STRONG WIND GUSTS ARE POSSIBLE.

..MOSIER.. 04/08/2012

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

ATTN...WFO...SHV...HGX...FWD...

LAT...LON   32309572 32229538 31919494 31429477 30829485 30709545
            30859608 31379644 32029625 32309572

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Apr 7, 9:53 PM CDTMesoscale DiscussionSPCCrockett, Schleicher, Sutton, Terrell97 min
Apr 8, 1:27 PM CDTMesoscale DiscussionSPCDallas, Ellis, Henderson, Kaufman, Navarro, Rockwall93 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.