Alert archive / Kansas / Mesoscale Discussions in 2012

Mesoscale Discussion 733

May 6, 201227 counties in Kansas; Platte County, Missouri

The Storm Prediction Center issued this mesoscale discussion at May 6, 2012, 2:40 PM CDT for 27 counties in Kansas; Platte County, Missouri. It was in force for 95 min.

The area

The outline as issued.

The facts

Issued
May 6, 2012, 2:40 PM CDT (19:40 UTC)
Expired
May 6, 2012, 4:15 PM CDT
In force
95 min
Issued by
the Storm Prediction Center
Chance of a watch
60%
All 28 counties

Allen County, KS, Anderson County, KS, Butler County, KS, Chase County, KS, Coffey County, KS, Cowley County, KS, Douglas County, KS, Elk County, KS, Franklin County, KS, Greenwood County, KS, Harvey County, KS, Jefferson County, KS, Johnson County, KS, Leavenworth County, KS, Linn County, KS, Lyon County, KS, Marion County, KS, Miami County, KS, Morris County, KS, Osage County, KS, Sedgwick County, KS, Shawnee County, KS, Sumner County, KS, Wabaunsee County, KS, Wilson County, KS, Woodson County, KS, Wyandotte County, KS, Platte County, MO

The radar

The Topeka radar (KTWX), 95 km from the middle of the area, began a volume at 19:42 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

Topeka, KS (KTOP), launched 12:00Z, 7.7 hours before the alert went out and 116 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, Topeka, KS at 12:00Z on 2012-05-06Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 1880 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, Topeka, KS at 12:00Z on 2012-05-06The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 286 square meters per square second.193958Sfc1 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
1880 J/kg
Mixed-layer CIN
-240 J/kg
Mixed-layer LCL
732 m above ground
0-6 km bulk shear
22 kt
0-1 km storm-relative helicity
286 m²/s²
0-3 km storm-relative helicity
218 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.

661 
ACUS11 KWNS 061940
SWOMCD
SPC MCD 061940 
MOZ000-KSZ000-062115-

MESOSCALE DISCUSSION 0733
NWS STORM PREDICTION CENTER NORMAN OK
0240 PM CDT SUN MAY 06 2012

AREAS AFFECTED...SRN THROUGH NERN KS

CONCERNING...SEVERE POTENTIAL...WATCH POSSIBLE 

VALID 061940Z - 062115Z

PROBABILITY OF WATCH ISSUANCE...60 PERCENT

SUMMARY...ISOLATED SEVERE THUNDERSTORMS ARE EXPECTED TO DEVELOP
ALONG SLOW MOVING COLD FRONT ACROSS KS OVER THE NEXT FEW HOURS.  WW
IS BEING CONSIDERED FOR THIS REGION.

DISCUSSION...DESPITE THE CONSIDERABLE HIGH CLOUDS NOTED ACROSS KS
INHIBITION IS GRADUALLY WEAKENING ALONG SFC FRONT THAT STRETCHES
FROM NEAR STJ TO ICT.  TEMPERATURES HAVE WARMED INTO THE LOWER 80S
AND CONVECTION IS GRADUALLY DEEPENING ALONG THE FRONTAL ZONE. 
FORECAST SOUNDINGS SUGGEST THIS IS SUFFICIENT FOR TSTM
DEVELOPMENT...ESPECIALLY GIVEN THE CONVERGENCE NOTED ALONG THE SLOW
MOVING BOUNDARY.  LATEST THINKING IS ISOLATED STORMS WILL EVOLVE
OVER THE NEXT FEW HOURS WITHIN FAIRLY UNSTABLE AIRMASS THEN SPREAD
EWD ACROSS MUCH OF ERN KS INTO WRN MO.  WITH STRONGER SHEAR TRAILING
THE WIND SHIFT IT APPEARS LARGE HAIL AND STRONG WINDS WILL BE THE
PRIMARY SEVERE THREATS.

..DARROW/MEAD.. 05/06/2012

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

ATTN...WFO...SGF...EAX...TOP...ICT...

LAT...LON   37269832 38609694 39119609 39599445 38159435 37099644
            37269832

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
May 6, 3:49 PM CDTSevere Thunderstorm WatchSPCAllen, Anderson, Atchison, Butler, Chase, Coffey and 17 more7 hr
May 6, 4:55 AM CDTMesoscale DiscussionSPCAtchison, Nodaway, Worth2 hr
May 6, 9:29 AM CDTSevere Thunderstorm WatchSPCClark, Scotland4 hr
May 6, 1:22 PM CDTMesoscale DiscussionSPCAudrain, Benton, Boone, Callaway, Chariton, Cooper and 13 more53 min
May 6, 1:42 PM CDTSevere Thunderstorm WatchSPCAdair, Audrain, Boone, Caldwell, Carroll, Chariton and 25 more7 hr
May 6, 3:56 PM CDTMesoscale DiscussionSPCAdair, Audrain, Boone, Caldwell, Carroll, Chariton and 25 more64 min

Nearby

Mesoscale Discussions in Kansas, 2012Mesoscale Discussions in Missouri, 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.