Alert archive / Oklahoma / Mesoscale Discussions in 2012

Mesoscale Discussion 2216

December 25, 201212 counties in Oklahoma; Clay County, Wichita County, Wilbarger County, Texas

The Storm Prediction Center issued this mesoscale discussion at Dec 25, 2012, 2:50 PM CST for 12 counties in Oklahoma; Clay County, Wichita County, Wilbarger County, Texas. It was in force for 4 hr.

The area

The outline as issued.

The facts

Issued
Dec 25, 2012, 2:50 PM CST (20:50 UTC)
Expired
Dec 25, 2012, 6:45 PM CST
In force
4 hr
Issued by
the Storm Prediction Center

Counties Beckham County, OK, Caddo County, OK, Comanche County, OK, Cotton County, OK, Custer County, OK, Greer County, OK, Jackson County, OK, Jefferson County, OK, Kiowa County, OK, Stephens County, OK, Tillman County, OK, Washita County, OK, Clay County, TX, Wichita County, TX, Wilbarger County, TX

The radar

The Altus AFB radar (KFDR), 31 km from the middle of the area, began a volume at 20:47 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

Norman, OK (KOUN), launched 12:00Z, 8.8 hours before the alert went out and 142 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, Norman, OK 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°0°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Norman, OK at 12:00Z on 2012-12-25The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 312 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
524 m above ground
0-6 km bulk shear
41 kt
0-1 km storm-relative helicity
312 m²/s²
0-3 km storm-relative helicity
223 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.

600 
ACUS11 KWNS 252050
SWOMCD
SPC MCD 252050 
OKZ000-TXZ000-260045-

MESOSCALE DISCUSSION 2216
NWS STORM PREDICTION CENTER NORMAN OK
0250 PM CST TUE DEC 25 2012

AREAS AFFECTED...SWRN/S-CNTRL OK AND WRN N TX

CONCERNING...BLIZZARD 

VALID 252050Z - 260045Z

SUMMARY...BLIZZARD CONDITIONS WILL CONTINUE THROUGH AROUND 22Z-00Z
BEFORE WIND SPEEDS AND SNOW RATES BEGIN DECREASING.
HOWEVER...BLOWING/DRIFTING SNOW WILL REMAIN A CONCERN INTO TONIGHT.

DISCUSSION...SFC OBSERVATIONS SUGGEST THAT NLY WINDS OF 20-35 MPH
WITH GUSTS REACHING 35-45 MPH ARE OCCURRING IN ASSOCIATION WITH A
TIGHT SFC PRESSURE GRADIENT. THESE WINDS ARE COMBINING WITH FALLING
SNOW/FRESHLY FALLEN SNOW TO CREATE WIDESPREAD VISIBILITIES BELOW
0.75 MILE...WITH VISIBILITIES AOB 0.25 MILE ALSO OCCURRING. THE BAND
OF HEAVIEST SNOW EXTENDS FROM 25 NW LTS TO 15 S FSI TO 20 WSW ADM AS
OF AROUND 2040Z...AND THIS BAND WILL CONTINUE SHIFTING SWD TOWARD
AND S OF THE RED RIVER DURING THE NEXT COUPLE OF HOURS.
HOWEVER...WITH FORCING FOR ASCENT WEAKENING WITH TIME...SNOWFALL
RATES SHOULD DECREASE DURING THE 22Z-00Z TIME PERIOD. WIND SPEEDS
WILL ALSO DECREASE DURING THIS SAME TIME PERIOD...AS THE SFC
PRESSURE GRADIENT SLACKENS. THESE FACTORS WILL SERVE TO DECREASE THE
BLIZZARD THREAT LATE THIS AFTERNOON INTO THE EVENING...THOUGH
BLOWING/DRIFTING OF FRESHLY FALLEN SNOW WILL LIKELY CONTINUE INTO
TONIGHT AS NLY WINDS OF 15-25 MPH WITH HIGHER GUSTS CONTINUE.

..COHEN.. 12/25/2012

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

ATTN...WFO...FWD...OUN...

LAT...LON   33689841 33959915 34389974 35049984 35389968 35759911
            35119804 34519738 33879739 33689841

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Dec 25, 2:32 AM CSTMesoscale DiscussionSPCBlaine, Caddo, Canadian, Cleveland, Comanche, Creek and 21 more4 hr
Dec 25, 9:31 AM CSTMesoscale DiscussionSPCCaddo, Canadian, Carter, Comanche, Cotton, Garvin and 9 more5 hr
Dec 25, 11:02 AM CSTMesoscale DiscussionSPCCaddo, Carter, Comanche, Cotton, Garvin, Grady and 7 more4 hr
Dec 25, 12:11 PM CSTMesoscale DiscussionSPCAtoka, Bryan, Choctaw, Coal, Haskell, Johnston and 6 more5 hr
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, 9:02 AM CSTSevere Thunderstorm WatchSPCAngelina, Cherokee, Gregg, Harrison, Marion, Nacogdoches and 6 more7 hr
Dec 25, 9:17 AM CSTTornado WatchSPCAustin, Brazoria, Chambers, Fort Bend, Galveston, Grimes and 16 more8 hr
Dec 25, 12:19 PM CSTMesoscale DiscussionSPCChambers, Galveston, Hardin, Jasper, Jefferson, Newton and 1 more71 min
Dec 25, 1:00 PM CSTMesoscale DiscussionSPCBowie, Camp, Cass, Collin, Dallas, Delta and 16 more5 hr

Nearby

Mesoscale Discussions in Oklahoma, 2012Mesoscale 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.