Alert archive / Texas / Mesoscale Discussions in 2012

Mesoscale Discussion 613

April 28, 20125 counties in Oklahoma; 18 counties in Texas

The Storm Prediction Center issued this mesoscale discussion at Apr 28, 2012, 3:54 PM CDT for 5 counties in Oklahoma; 18 counties in Texas. It was in force for 66 min.

The area

The outline as issued.

The facts

Issued: Apr 28, 2012, 3:54 PM CDT (20:54 UTC)
Expired: Apr 28, 2012, 5:00 PM CDT
In force: 66 min
Issued by: the Storm Prediction Center

All 23 counties

Comanche County, OK, Cotton County, OK, Jackson County, OK, Kiowa County, OK, Tillman County, OK, Archer County, TX, Baylor County, TX, Clay County, TX, Fisher County, TX, Foard County, TX, Hardeman County, TX, Haskell County, TX, Jones County, TX, King County, TX, Knox County, TX, Nolan County, TX, Shackelford County, TX, Stonewall County, TX, Taylor County, TX, Throckmorton County, TX, Wichita County, TX, Wilbarger County, TX, Young County, TX

The radar

The Altus AFB radar (KFDR), 103 km from the middle of the area, began a volume at 20:55 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.

Severe Thunderstorm Watch 200Apr 28, 6:35 PM CDT

The nearest sounding before it

Fort Worth, TX (KFWD), launched 12:00Z, 8.9 hours before the alert went out and 210 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-p

Temperature in red, dew point in green, the mixed-layer parcel dashed.

Hodograph

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: 262 J/kg
Mixed-layer CIN: -725 J/kg
Mixed-layer LCL: 814 m above ground
0-6 km bulk shear: 39 kt
0-1 km storm-relative helicity: 394 m²/s²
0-3 km storm-relative helicity: 334 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.

446 
ACUS11 KWNS 282054
SWOMCD
SPC MCD 282054 
OKZ000-TXZ000-282200-

MESOSCALE DISCUSSION 0613
NWS STORM PREDICTION CENTER NORMAN OK
0354 PM CDT SAT APR 28 2012

AREAS AFFECTED...SW OK...NW TX

CONCERNING...SEVERE POTENTIAL...WATCH LIKELY 

VALID 282054Z - 282200Z

ISOLATED THUNDERSTORMS ARE EXPECTED TO DEVELOP DURING THE NEXT FEW
HOURS WITH THE CONDITIONAL THREAT OF VERY LARGE HAIL AND DAMAGING
WINDS. 

20Z SURFACE ANALYSIS INDICATED AN AREA OF LOW PRESSURE NEAR SPS WITH
A DIFFUSE DRYLINE EXTENDING SWWD INTO THE PERMIAN BASIN. DEWPOINTS
EAST OF THE DRYLINE ARE IN THE LOW 60S. LATEST OBJECTIVE ANALYSIS
INDICATES THIS AREA REMAINS CAPPED WITH 850 TEMPS AOA 17 DEG C.
HOWEVER...RECENT SATELLITE IMAGERY DEPICTS INCREASING MID-LEVEL
CLOUDS ACROSS THE EDWARDS PLATEAU AS A SHORTWAVE TROUGH MOVES NEWD
OUT OF MEXICO. THIS SHORTWAVE IS EXPECTED TO PROVIDE ENOUGH LIFT TO
WEAKEN THE CAP AND ALLOW FOR ISOLATED THUNDERSTORM DEVELOPMENT OVER
NW TX AND SW OK. ENVIRONMENTAL CONDITIONS /SBCAPE AOA 1500 J/KG AND
EFFECTIVE SHEAR VALUES AOA 30 KTS/ INDICATE ORGANIZED UPDRAFTS ARE
LIKELY. AS A RESULT...A FEW SUPERCELLS ARE POSSIBLE WITH THE PRIMARY
THREAT OF VERY LARGE HAIL. ADDITIONALLY...DCAPE VALUES OVER 1000
J/KG INDICATE DAMAGING WINDS ARE POSSIBLE. RELATIVELY WEAK SURFACE
WINDS SHOULD LIMIT THE TORNADO POTENTIAL WITH THE POSSIBLE EXCEPTION
OF BACKED LOW-LEVEL SHEAR NEAR THE STALLED FRONTAL ZONE ORIENTATED
SW TO NE ACROSS OK.

..MOSIER.. 04/28/2012

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

ATTN...WFO...FWD...OUN...SJT...LUB...MAF...

LAT...LON   35019897 34859828 34469801 33979803 33549816 32969866
            32679901 32359944 32079981 32010007 32090044 32290078
            32740079 33390057 34060023 34699969 34889936 35019897

SPC that day

Everything else SPC issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Apr 28, 6:33 PM CDT	Severe Thunderstorm Watch	SPC	Alfalfa, Beckham, Blaine, Caddo, Canadian, Cleveland and 31 more	7 hr
Apr 28, 6:46 PM CDT	Mesoscale Discussion	SPC	Blaine, Caddo, Canadian, Cleveland, Comanche, Cotton and 18 more	59 min

Nearby

Mesoscale Discussions in Texas, 2012 Mesoscale Discussions in Oklahoma, 2012 Every 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.