Alert archive / Kansas / Mesoscale Discussions in 2012

Mesoscale Discussion 504

April 12, 201212 counties in Kansas; 5 counties in Nebraska

The Storm Prediction Center issued this mesoscale discussion at Apr 12, 2012, 7:53 PM CDT for 12 counties in Kansas; 5 counties in Nebraska. It was in force for 97 min.

The area

The outline as issued.

The facts

Issued: Apr 12, 2012, 7:53 PM CDT (00:53 UTC)
Expired: Apr 12, 2012, 9:30 PM CDT
In force: 97 min
Issued by: the Storm Prediction Center

Counties Cheyenne County, KS, Decatur County, KS, Gove County, KS, Lane County, KS, Logan County, KS, Rawlins County, KS, Scott County, KS, Sheridan County, KS, Sherman County, KS, Thomas County, KS, Wallace County, KS, Wichita County, KS, Dundy County, NE, Frontier County, NE, Hayes County, NE, Hitchcock County, NE, Red Willow County, NE

The radar

The Goodland radar (KGLD), 48 km from the middle of the area, began a volume at 00:52 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 159Apr 12, 8:40 PM CDT

The nearest sounding before it

Denver, CO (KDNR), launched 00:00Z, 0.9 hours before the alert went out and 173 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: 23 J/kg
Mixed-layer CIN: -23 J/kg
Mixed-layer LCL: 2712 m above ground
0-6 km bulk shear: 69 kt
0-1 km storm-relative helicity: 4 m²/s²
0-3 km storm-relative helicity: 148 m²/s²
Significant tornado parameter: 0.0
Supercell composite: -0.1

Open this sounding in Storm Lab

The text

As transmitted, in the capitals the NWS used until 2016.

149 
ACUS11 KWNS 130053
SWOMCD
SPC MCD 130053 
NEZ000-KSZ000-130230-

MESOSCALE DISCUSSION 0504
NWS STORM PREDICTION CENTER NORMAN OK
0753 PM CDT THU APR 12 2012

AREAS AFFECTED...SOUTHWEST NEB/WESTERN KS

CONCERNING...TORNADO WATCH 157...

VALID 130053Z - 130230Z

THE SEVERE WEATHER THREAT FOR TORNADO WATCH 157 CONTINUES.

TORNADO WATCH 157 CONTINUES UNTIL 02Z...WITH CONTINUED POTENTIAL FOR
LARGE HAIL/PERHAPS A FEW TORNADOES ESPECIALLY ACROSS FAR SOUTHWEST
NEB/FAR NORTHWEST KS IN THE SHORT-TERM. GIVEN THE SCHEDULED 02Z
EXPIRATION OF WW 157...A REPLACEMENT WATCH MAY BE NEEDED OVER THE
NEXT HOUR PENDING CONVECTIVE TRENDS.

A RELATIVELY FAVORABLE ENVIRONMENT REMAINS ACROSS FAR SOUTHWEST
NEB/FAR NORTHWEST KS WHERE A FEW SUPERCELLS ARE STILL ONGOING AS OF
0045Z. THIS CORRIDOR IS NEAR/IMMEDIATELY NORTHEAST OF A 998 MB
SURFACE LOW/ASSOCIATED TRIPLE POINT WHERE CONVERGENCE IS MAXIMIZED
AND RELATIVELY STRONG PRESSURE FALLS ARE STILL NOTED /2-3 MB PER 2
HR/ AS OF 00Z. WITH A NARROW CORRIDOR OF WEAK TO MODERATELY UNSTABLE
AND UNOVERTURNED AIR PERSISTING...SUPERCELL-FAVORABLE HODOGRAPHS
ACCENTUATED BY MODERATELY STRONG LOW LEVEL SHEAR /200+ 0-1 KM SRH
PER GOODLAND WSR-88D VWP/ WILL CONTINUE TO SUPPORT SOME TORNADO
THREAT EVEN WHILE BOUNDARY LAYER CINH TENDS TO INCREASE THIS
EVENING. IMMEDIATELY WEST...STORMS SHOULD OTHERWISE INCREASE IN A
NORTH-SOUTH FASHION IN VICINITY OF THE EASTWARD-ADVANCING COLD
FRONT...WITH SEVERE WIND/HAIL THE PRIMARY HAZARDS AS THIS MODE
BECOMES MORE DOMINANT.

THE SOUTHERN EXTENT OF SURFACE BASED DEEP CONVECTIVE INITIATION IS
MORE UNCERTAIN INTO SOUTHWEST KS. WHILE LOW-LEVEL MOISTURE HAS
INCREASED SOMEWHAT...A SLIGHTLY COOLING BOUNDARY LAYER IN ADDITION
TO MID-HIGH LEVEL COVER HAS GRADUALLY INCREASED CINH WHILE PUTTING
THE LIKELIHOOD OF SFC BASED INITIATION INTO QUESTION. THAT SAID...AN
INCREASE IN CONVERGENCE APPEARS TO BE OCCURRING...SUCH THAT SEVERE
TSTM DEVELOPMENT CANNOT BE RULED OUT.

..GUYER.. 04/13/2012

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

ATTN...WFO...GID...LBF...DDC...GLD...

LAT...LON   39830187 41190137 40360013 38400044 38000171 39830187

SPC that day

Everything else SPC issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Apr 12, 8:38 PM CDT	Severe Thunderstorm Watch	SPC	Cheyenne, Decatur, Gove, Graham, Greeley, Lane and 9 more	4 hr
Apr 12, 11:24 PM CDT	Mesoscale Discussion	SPC	Decatur, Gove, Graham, Norton, Phillips, Sheridan and 1 more	96 min
Apr 13, 2:37 PM CDT	Mesoscale Discussion	SPC	Allen, Anderson, Bourbon, Chautauqua, Cherokee, Coffey and 9 more	113 min
Apr 13, 3:40 PM CDT	Severe Thunderstorm Watch	SPC	Allen, Anderson, Bourbon, Butler, Chase, Chautauqua and 19 more	6 hr
Apr 13, 5:40 PM CDT	Mesoscale Discussion	SPC	Allen, Anderson, Bourbon, Chautauqua, Cherokee, Coffey and 14 more	65 min
Apr 12, 8:57 PM CDT	Mesoscale Discussion	SPC	Blaine, Buffalo, Custer, Dawson, Franklin, Furnas and 7 more	93 min

Nearby

Mesoscale Discussions in Kansas, 2012 Mesoscale Discussions in Nebraska, 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.