Alert archive / Oklahoma / Mesoscale Discussions in 2012

Mesoscale Discussion 319

March 21, 201227 counties in Oklahoma; 7 counties in Texas

The Storm Prediction Center issued this mesoscale discussion at Mar 21, 2012, 12:39 PM CDT for 27 counties in Oklahoma; 7 counties in Texas. It was in force for 2 hr.

The area

The outline as issued.

The facts

Issued: Mar 21, 2012, 12:39 PM CDT (17:39 UTC)
Expired: Mar 21, 2012, 2:45 PM CDT
In force: 2 hr
Issued by: the Storm Prediction Center

All 34 counties

Beckham County, OK, Caddo County, OK, Canadian County, OK, Carter County, OK, Cleveland County, OK, Comanche County, OK, Cotton County, OK, Custer County, OK, Dewey County, OK, Garvin County, OK, Grady County, OK, Greer County, OK, Jackson County, OK, Jefferson County, OK, Johnston County, OK, Kiowa County, OK, Love County, OK, Marshall County, OK, McClain County, OK, Murray County, OK, Oklahoma County, OK, Pontotoc County, OK, Pottawatomie County, OK, Roger Mills County, OK, Stephens County, OK, Tillman County, OK, Washita County, OK, Clay County, TX, Collin County, TX, Cooke County, TX, Denton County, TX, Grayson County, TX, Montague County, TX, Wise County, TX

The radar

The Altus AFB radar (KFDR), 76 km from the middle of the area, began a volume at 17:39 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, 5.7 hours before the alert went out and 100 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: 5 J/kg
Mixed-layer CIN: -100 J/kg
Mixed-layer LCL: 1007 m above ground
0-6 km bulk shear: 98 kt
0-1 km storm-relative helicity: -26 m²/s²
0-3 km storm-relative helicity: 47 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.

240 
ACUS11 KWNS 211740
SWOMCD
SPC MCD 211739
OKZ000-TXZ000-211945-

MESOSCALE DISCUSSION 0319
NWS STORM PREDICTION CENTER NORMAN OK
1239 PM CDT WED MAR 21 2012

AREAS AFFECTED...WESTERN/SOUTHERN/CENTRAL OK AND NORTH-CENTRAL TX

CONCERNING...SEVERE POTENTIAL...WATCH POSSIBLE

VALID 211739Z - 211945Z

LOW-TOPPED TSTMS CAPABLE OF HAIL TO SEVERE LEVELS ARE EXPECTED TO
DEVELOP/INCREASE THROUGH EARLY/MID AFTERNOON ESPECIALLY ACROSS
WESTERN/CENTRAL/SOUTHERN OF OK AS WELL AS NORTH-CENTRAL TX. HAIL
ASIDE...A FEW FUNNELS/BRIEF TORNADO MAY BE POSSIBLE AS WELL. A WATCH
COULD BE NEEDED THIS AFTERNOON.

A NEARLY VERTICALLY STACKED/CLOSED LOW CONTINUES TO SLOWLY SHIFT
EASTWARD ACROSS NORTH-CENTRAL TX/SOUTHWEST OK EARLY THIS AFTERNOON.
TIED TO THIS CYCLONE...REGIONAL 12Z OBSERVED SOUNDINGS AND MORE
CONTEMPORARY RUC DIAGNOSTICS SUGGEST MID-LEVEL /500 MB/ TEMPERATURES
MAY BE AS COLD AS -25 TO -27 C. WITH AMPLE INSOLATION...LITTLE
NEAR-SURFACE INHIBITION NOW REMAINS AS SURFACE TEMPERATURES HAVE
WARMED INTO THE UPPER 50S/LOWER 60S F IN MOST AREAS AS OF 17Z. WHILE
LOW-LEVEL MOISTURE WILL REMAIN RATHER MODEST /AND PERHAPS MIX-OUT TO
A DEGREE LATER THIS AFTERNOON/...VERY STEEP LAPSE RATES/COOL THERMAL
PROFILES ALOFT SHOULD BE EFFICIENT IN PRODUCING HAIL THIS
AFTERNOON...SOME OF IT TO/ABOVE SEVERE LEVELS. THE STEEP LAPSE RATES
AND A VORTICITY-RICH ENVIRONMENT IN CLOSE PROXIMITY TO THE STACKED
LOW COULD ALSO YIELD FUNNELS/PERHAPS A BRIEF TORNADO AS WELL...EVEN
WITH MODEST VERTICAL SHEAR.

..GUYER.. 03/21/2012

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

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

LAT...LON   35789985 36119961 36309911 35689827 35509670 33409612
            32949696 33149768 34009845 34739978 35789985

SPC that day

Everything else SPC issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Mar 20, 8:02 PM CDT	Tornado Watch	SPC	Jasper, Jefferson, Newton, Orange	4 hr
Mar 20, 10:23 PM CDT	Mesoscale Discussion	SPC	Newton	67 min

Nearby

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