Alert archive / Texas / Mesoscale Discussions in 2012

Mesoscale Discussion 2203

December 25, 20124 parishes in Louisiana; 43 counties in Texas

The Storm Prediction Center issued this mesoscale discussion at Dec 25, 2012, 1:01 AM CST for 4 parishes in Louisiana; 43 counties in Texas. It was in force for 59 min.

The area

The outline as issued.

The facts

Issued
Dec 25, 2012, 1:01 AM CST (07:01 UTC)
Expired
Dec 25, 2012, 2:00 AM CST
In force
59 min
Issued by
the Storm Prediction Center
Chance of a watch
80%
All 47 counties

Allen Parish, LA, Beauregard Parish, LA, Sabine Parish, LA, Vernon Parish, LA, Anderson County, TX, Angelina County, TX, Austin County, TX, Bell County, TX, Bosque County, TX, Brazos County, TX, Burleson County, TX, Cherokee County, TX, Coryell County, TX, Ellis County, TX, Falls County, TX, Freestone County, TX, Grimes County, TX, Hamilton County, TX, Hardin County, TX, Henderson County, TX, Hill County, TX, Houston County, TX, Jasper County, TX, Johnson County, TX, Lee County, TX, Leon County, TX, Limestone County, TX, Madison County, TX, McLennan County, TX, Milam County, TX, Montgomery County, TX, Nacogdoches County, TX, Navarro County, TX, Newton County, TX, Polk County, TX, Robertson County, TX, Sabine County, TX, San Augustine County, TX, San Jacinto County, TX, Shelby County, TX, Somervell County, TX, Trinity County, TX, Tyler County, TX, Walker County, TX, Waller County, TX, Washington County, TX, Williamson County, TX

The radar

The Ft Hood radar (KGRK), 170 km from the middle of the area, began a volume at 07:00 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 watches that followed

Watches SPC issued over any of the same counties within four hours of this discussion.

The nearest sounding before it

Shreveport, LA (KSHV), launched 00:00Z, 7.0 hours before the alert went out and 232 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 00:00Z 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°0°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Shreveport, LA at 00:00Z on 2012-12-25The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 67 square meters per square second.1939587897117Sfc1 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
1948 m above ground
0-6 km bulk shear
45 kt
0-1 km storm-relative helicity
67 m²/s²
0-3 km storm-relative helicity
124 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.

564 
ACUS11 KWNS 250702
SWOMCD
SPC MCD 250701
LAZ000-TXZ000-250800-

MESOSCALE DISCUSSION 2203
NWS STORM PREDICTION CENTER NORMAN OK
0101 AM CST TUE DEC 25 2012

AREAS AFFECTED...PORTIONS OF CENTRAL/ERN TX...WRN LA

CONCERNING...SEVERE POTENTIAL...WATCH LIKELY

VALID 250701Z - 250800Z

PROBABILITY OF WATCH ISSUANCE...80 PERCENT

SUMMARY...TSTMS WILL CONTINUE TO DEVELOP/INTENSIFY NORTH OF A WARM
FRONT THROUGH THE EARLY MORNING HOURS. SUPERCELL TSTMS ARE LIKELY
WITH LARGE HAIL POSING THE PRIMARY THREAT. A WW IS LIKELY PRIOR TO
08Z.

DISCUSSION...TSTMS ARE DEVELOPING/INTENSIFYING NORTH OF A WARM FRONT
THAT WAS LOCATED FROM COT NEWD TO JUST NW OF HOU TO NORTH OF BPT AT
06Z. THIS DEVELOPMENT IS IN RESPONSE TO INCREASING WAA IN ADVANCE OF
AN INTENSE SEWD-MOVING SHORTWAVE APCHG W TX. THE ENVIRONMENT NORTH
OF THE WARM FRONT IS CHARACTERIZED BY 40-45 KT DEEP LAYER SHEAR THAT
IS FORECAST TO INCREASE TO 55-60 KT BY 12Z. MUCAPES OF 1000-1500
J/KG WILL SUPPORT ELEVATED SUPERCELLS WITH A THREAT OF LARGE HAIL.
STORMS ARE EXPECTED TO INCREASE IN COVERAGE AND INTENSITY OVER THE
NEXT FEW HOURS AND A SVR TSTM WATCH WILL LIKELY BE NEEDED BY 08Z.

..BUNTING/MEAD.. 12/25/2012

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

ATTN...WFO...LCH...SHV...HGX...FWD...EWX...

LAT...LON   30269302 30339422 30199495 29929562 29859628 30179685
            30539766 31019814 31519833 31949827 32249806 32409766
            32489717 32329611 32209514 31979429 31729341 31439287
            30929248 30269302

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Dec 25, 1:37 AM CSTSevere Thunderstorm WatchSPCAcadia, Allen, Avoyelles, Beauregard, Calcasieu, De Soto and 9 more7 hr
Dec 25, 5:56 AM CSTMesoscale DiscussionSPCAcadia, Allen, Avoyelles, Beauregard, Calcasieu, De Soto and 10 more94 min
Dec 25, 7:00 AM CSTMesoscale DiscussionSPCAcadia, Allen, Ascension, Assumption, Beauregard, Calcasieu and 24 more60 min
Dec 25, 7:28 AM CSTTornado WatchSPCAcadia, Ascension, Assumption, East Baton Rouge, East Feliciana, Iberia and 19 more6 hr
Dec 25, 8:46 AM CSTMesoscale DiscussionSPCAllen, Avoyelles, Beauregard, Bienville, Calcasieu, Caldwell and 21 more59 min
Dec 25, 9:02 AM CSTSevere Thunderstorm WatchSPCBienville, Bossier, Caddo, Caldwell, Catahoula, Claiborne and 20 more7 hr
Dec 25, 9:17 AM CSTTornado WatchSPCAcadia, Allen, Avoyelles, Beauregard, Calcasieu, Cameron and 10 more8 hr
Dec 25, 12:19 PM CSTMesoscale DiscussionSPCAcadia, Allen, Ascension, Assumption, Avoyelles, Beauregard and 35 more71 min
Dec 25, 12:23 PM CSTMesoscale DiscussionSPCBienville, Caldwell, Catahoula, Concordia, East Carroll, Franklin and 13 more67 min
Dec 25, 12:58 PM CSTTornado Watch PDSSPCAscension, Assumption, Catahoula, Concordia, East Baton Rouge, East Feliciana and 20 more9 hr
Dec 25, 3:22 PM CSTMesoscale DiscussionSPCCaldwell, East Carroll, Morehouse, Richland, West Carroll53 min
Dec 25, 3:44 PM CSTMesoscale DiscussionSPCAscension, Assumption, East Baton Rouge, East Feliciana, Iberia, Iberville and 19 more91 min
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, 1:00 PM CSTMesoscale DiscussionSPCBowie, Camp, Cass, Collin, Dallas, Delta and 16 more5 hr
Dec 25, 2:50 PM CSTMesoscale DiscussionSPCClay, Wichita, Wilbarger4 hr

Nearby

Mesoscale Discussions in Texas, 2012Mesoscale Discussions in Louisiana, 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.