Alert archive / Oklahoma / Mesoscale Discussions in 2012

Mesoscale Discussion 616

April 28, 201224 counties in Oklahoma; Hardeman County, Wichita County, Wilbarger County, Texas

The Storm Prediction Center issued this mesoscale discussion at Apr 28, 2012, 6:46 PM CDT for 24 counties in Oklahoma; Hardeman County, Wichita County, Wilbarger County, Texas. It was in force for 59 min.

The area

The outline as issued.

The facts

Issued
Apr 28, 2012, 6:46 PM CDT (23:46 UTC)
Expired
Apr 28, 2012, 7:45 PM CDT
In force
59 min
Issued by
the Storm Prediction Center
All 27 counties

Blaine County, OK, Caddo County, OK, Canadian County, OK, Cleveland County, OK, Comanche County, OK, Cotton County, OK, Custer County, OK, Dewey County, OK, Garfield County, OK, Grady County, OK, Greer County, OK, Harmon County, OK, Jackson County, OK, Kingfisher County, OK, Kiowa County, OK, Lincoln County, OK, Logan County, OK, Major County, OK, McClain County, OK, Noble County, OK, Oklahoma County, OK, Payne County, OK, Tillman County, OK, Washita County, OK, Hardeman County, TX, Wichita County, TX, Wilbarger County, TX

The radar

The Norman radar (KTLX), 93 km from the middle of the area, began a volume at 23:47 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 watches that followed

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

The nearest sounding before it

Norman, OK (KOUN), launched 12:00Z, 11.8 hours before the alert went out and 80 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 2012-04-28Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 1418 joules per kilogram.LCLLFCEL10008507005003002001001 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 2012-04-28The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 408 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
1418 J/kg
Mixed-layer CIN
-296 J/kg
Mixed-layer LCL
548 m above ground
0-6 km bulk shear
37 kt
0-1 km storm-relative helicity
408 m²/s²
0-3 km storm-relative helicity
430 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.

673 
ACUS11 KWNS 282346
SWOMCD
SPC MCD 282346 
OKZ000-TXZ000-290045-

MESOSCALE DISCUSSION 0616
NWS STORM PREDICTION CENTER NORMAN OK
0646 PM CDT SAT APR 28 2012

AREAS AFFECTED...FAR NWRN TX...SWRN/WRN/CNTRL OK

CONCERNING...SEVERE THUNDERSTORM WATCH 200...

VALID 282346Z - 290045Z

THE SEVERE WEATHER THREAT FOR SEVERE THUNDERSTORM WATCH 200
CONTINUES.

SVR THUNDERSTORM WATCH 200 HAS BEEN ISSUED FOR NWRN TX AND PORTIONS
OF SWRN/WRN/CNTRL OK. AREA FROM THE RED RIVER N-NEWD WILL BE
MONITORED DURING THE NIGHT FOR POSSIBLE UPGRADE TO TORNADO WATCH.

AT 2345Z...A STATIONARY FRONT...WHICH IS SLOWLY MOVING W-NWWD IN
RESPONSE TO APPROACHING FOUR CORNERS UPR DISTURBANCE...WAS LOCATED
FROM ROUGHLY 45 W OF SPS NEWD TO 15 N OF CQB. COMBINATION OF
BOUNDARY LAYER DESTABILIZATION AND WEAK UPR IMPULSE MOVING ACROSS W
TX IS AIDING IN ISOLATED THUNDERSTORM DEVELOPMENT NEAR THE FRONT
OVER NWRN TX. DURING THE NIGHT...ADDITIONAL SCATTERED THUNDERSTORM
DEVELOPMENT WILL BECOME PROBABLE ALONG THE OK PORTION OF THE FRONT
AS LOW-LEVEL WAA INCREASES IN RESPONSE TO STRENGTHENING SLY LLJ.
THOUGH SUPERCELLS PRODUCING LARGE HAIL /POSSIBLY SIG HAIL WITH
DIAMETERS UP TO 3 INCHES/ AND DAMAGING WIND GUSTS WILL BE THE
PRIMARY SVR WEATHER THREAT...THE INCREASE IN LOW-LEVEL FLOW WILL
LEAD TO ENLARGEMENT OF HODOGRAPHS OVER OK...WHICH MAY INCREASE THE
POTENTIAL FOR TORNADOES AS WELL. THUS...PORTIONS OF SVR THUNDERSTORM
WATCH 200 OVER OK WILL BE MONITORED DURING THE NEXT FEW HRS FOR
POSSIBLE UPGRADE TO TORNADO.

..GARNER.. 04/28/2012

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

ATTN...WFO...TSA...OUN...AMA...

LAT...LON   34729770 33899845 33739888 33849958 34820000 36289899
            36549788 36429694 36059655 34729770

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Apr 28, 3:54 PM CDTMesoscale DiscussionSPCComanche, Cotton, Jackson, Kiowa, Tillman66 min
Apr 28, 6:33 PM CDTSevere Thunderstorm WatchSPCAlfalfa, Beckham, Blaine, Caddo, Canadian, Cleveland and 31 more7 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.