Alert archive / Texas / Mesoscale Discussions in 2012

Mesoscale Discussion 2213

December 25, 20126 counties in Arkansas; 22 counties in Texas

The Storm Prediction Center issued this mesoscale discussion at Dec 25, 2012, 1:00 PM CST for 6 counties in Arkansas; 22 counties in Texas. It was in force for 5 hr.

The area

The outline as issued.

The facts

Issued
Dec 25, 2012, 1:00 PM CST (19:00 UTC)
Expired
Dec 25, 2012, 6:00 PM CST
In force
5 hr
Issued by
the Storm Prediction Center
All 28 counties

Columbia County, AR, Hempstead County, AR, Lafayette County, AR, Little River County, AR, Miller County, AR, Nevada County, AR, Bowie County, TX, Camp County, TX, Cass County, TX, Collin County, TX, Dallas County, TX, Delta County, TX, Denton County, TX, Fannin County, TX, Franklin County, TX, Grayson County, TX, Hopkins County, TX, Hunt County, TX, Kaufman County, TX, Lamar County, TX, Marion County, TX, Morris County, TX, Rains County, TX, Red River County, TX, Rockwall County, TX, Titus County, TX, Upshur County, TX, Wood County, TX

The radar

The Shreveport radar (KSHV), 152 km from the middle of the area, began a volume at 19:02 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, 7.0 hours before the alert went out and 221 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 2012-12-25Temperature 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°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Fort Worth, TX at 12:00Z on 2012-12-25The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 279 square meters per square second.19395878Sfc1 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
1037 m above ground
0-6 km bulk shear
60 kt
0-1 km storm-relative helicity
279 m²/s²
0-3 km storm-relative helicity
301 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.

011 
ACUS11 KWNS 251900
SWOMCD
SPC MCD 251900 
ARZ000-LAZ000-TXZ000-OKZ000-260000-

MESOSCALE DISCUSSION 2213
NWS STORM PREDICTION CENTER NORMAN OK
0100 PM CST TUE DEC 25 2012

AREAS AFFECTED...N-CNTRL/NERN TX...SWRN AR...FAR NWRN LA...EXTREME
SERN OK

CONCERNING...HEAVY SNOW 

VALID 251900Z - 260000Z

SUMMARY...RAIN WILL TRANSITION TO SNOW AFTER A BRIEF PERIOD OF
SLEET. HEAVY SNOW IS ANTICIPATED...WITH SNOWFALL RATES OF 1-1.5
IN/HR POSSIBLE...ESPECIALLY TO THE NORTH OF A LINE FROM THE DFW AREA
TO TEXARKANA.

DISCUSSION...MOISTURE TRANSPORT/ASCENT ACCOMPANYING THE WRN BRANCH
OF A BIFURCATED WARM CONVEYOR BELT AND COLD CONVEYOR BELT STRUCTURES
NEAR AND S OF THE RED RIVER WILL MAINTAIN PRECIPITATION INTO THE
EVENING FROM N-CNTRL TX EWD TO THE ARKLATEX REGION. AS DEEPER COLD
AIR ADVANCES INTO THE AREA ON THE BACKSIDE OF A LOWER-MS-VALLEY SFC
LOW...LOWER TROPOSPHERIC TEMPERATURE PROFILES WILL COOL. THIS WILL
SUPPORT A PHASE CHANGE TO SNOW FROM W TO E...THOUGH A BRIEF PERIOD
OF SLEET MAY OCCUR. PER OBSERVATIONAL DATA AND CONSENSUS AMONGST
SHORT-RANGE...HIGH-RESOLUTION WRF GUIDANCE...THE CHANGEOVER TO SNOW
WILL LIKELY OCCUR AROUND THE DFW METROPLEX TO S OF DURANT OK AROUND
20Z...WITH A CHANGEOVER TO SNOW LIKELY OCCURRING OVER THE ARKLATEX
REGION BETWEEN 22Z AND 00Z. BASED ON RECENT TRENDS IN THE TRACK OF
THE MID-LEVEL VORT MAX PER WATER VAPOR IMAGERY AND ZONE OF INFERRED
ASCENT...THE HIGHEST SNOWFALL RATES ARE EXPECTED N OF A LINE FROM
THE DFW AREA TO TEXARKANA...WHERE SNOWFALL RATES OF 1-1.5 IN/HR WILL
BE MOST LIKELY. THESE RATES WILL BE IN ASSOCIATION WITH A
W/E-ORIENTED LOW-TO-MID-LEVEL CONFLUENCE AXIS AT THE BASE OF
STRONGER UPWARD MOTION. RELATIVELY WEAKER ASCENT WILL SUPPORT
SOMEWHAT LOWER RATES FARTHER SOUTH.

..COHEN.. 12/25/2012

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

ATTN...WFO...LZK...SHV...TSA...FWD...OUN...

LAT...LON   34019302 33249302 32799384 32559550 32629693 33239726
            33749692 33799621 33959442 34019302

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Dec 25, 9:02 AM CSTSevere Thunderstorm WatchSPCAshley, Chicot, Union7 hr
Dec 25, 12:11 PM CSTMesoscale DiscussionSPCCleburne, Conway, Crawford, Faulkner, Franklin, Garland and 20 more5 hr
Dec 25, 12:23 PM CSTMesoscale DiscussionSPCAshley, Chicot67 min
Dec 25, 2:14 PM CSTMesoscale DiscussionSPCBaxter, Boone, Carroll, Clay, Craighead, Cross and 10 more4 hr
Dec 25, 3:22 PM CSTMesoscale DiscussionSPCChicot53 min
Dec 25, 1:01 AM CSTMesoscale DiscussionSPCAnderson, Angelina, Austin, Bell, Bosque, Brazos and 37 more59 min
Dec 25, 1:37 AM CSTSevere Thunderstorm WatchSPCAnderson, Angelina, Bell, Bosque, Brazos, Burleson and 36 more7 hr
Dec 25, 5:56 AM CSTMesoscale DiscussionSPCAnderson, Angelina, Bell, Bosque, Brazos, Burleson and 38 more94 min
Dec 25, 7:00 AM CSTMesoscale DiscussionSPCBrazoria, Chambers, Galveston, Hardin, Harris, Jasper and 9 more60 min
Dec 25, 8:46 AM CSTMesoscale DiscussionSPCAngelina, Brazoria, Chambers, Cherokee, Fort Bend, Galveston and 26 more59 min
Dec 25, 9:17 AM CSTTornado WatchSPCAustin, Brazoria, Chambers, Fort Bend, Galveston, Grimes and 16 more8 hr
Dec 25, 9:31 AM CSTMesoscale DiscussionSPCArcher, Baylor, Clay, Cooke, Denton, Hood and 10 more5 hr
Dec 25, 11:02 AM CSTMesoscale DiscussionSPCWichita, Wilbarger4 hr
Dec 25, 12:19 PM CSTMesoscale DiscussionSPCChambers, Galveston, Hardin, Jasper, Jefferson, Newton and 1 more71 min
Dec 25, 2:50 PM CSTMesoscale DiscussionSPCClay, Wichita, Wilbarger4 hr

Nearby

Mesoscale Discussions in Texas, 2012Mesoscale Discussions in Arkansas, 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.