Alert archive / Kansas / Mesoscale Discussions in 2012

Mesoscale Discussion 170

February 28, 201215 counties in Kansas; 12 counties in Oklahoma

The Storm Prediction Center issued this mesoscale discussion at Feb 28, 2012, 7:57 PM CST for 15 counties in Kansas; 12 counties in Oklahoma. It was in force for 48 min.

The area

The outline as issued.

The facts

Issued: Feb 28, 2012, 7:57 PM CST (01:57 UTC)
Expired: Feb 28, 2012, 8:45 PM CST
In force: 48 min
Issued by: the Storm Prediction Center

All 27 counties

Butler County, KS, Chase County, KS, Chautauqua County, KS, Cowley County, KS, Elk County, KS, Greenwood County, KS, Harper County, KS, Harvey County, KS, Kingman County, KS, Lyon County, KS, Marion County, KS, McPherson County, KS, Reno County, KS, Sedgwick County, KS, Sumner County, KS, Alfalfa County, OK, Blaine County, OK, Garfield County, OK, Grant County, OK, Kay County, OK, Kingfisher County, OK, Logan County, OK, Major County, OK, Noble County, OK, Osage County, OK, Pawnee County, OK, Payne County, OK

The radar

The Wichita radar (KICT), 38 km from the middle of the area, began a volume at 02:00 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.

Tornado Watch 41Feb 28, 8:10 PM CST

The nearest sounding before it

Lamont, OK (KLMN), launched 00:00Z, 2.0 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-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: 386 J/kg
Mixed-layer CIN: -76 J/kg
Mixed-layer LCL: 660 m above ground
0-6 km bulk shear: 77 kt
0-1 km storm-relative helicity: 369 m²/s²
0-3 km storm-relative helicity: 461 m²/s²
Significant tornado parameter: 0.8
Supercell composite: 2.3

Open this sounding in Storm Lab

The text

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

573 
ACUS11 KWNS 290158
SWOMCD
SPC MCD 290157 COR
KSZ000-OKZ000-290245-

MESOSCALE DISCUSSION 0170
NWS STORM PREDICTION CENTER NORMAN OK
0757 PM CST TUE FEB 28 2012

AREAS AFFECTED...S-CNTRL/SERN KS...N-CNTRL OK

CONCERNING...TORNADO WATCH 40...

VALID 290157Z - 290245Z

CORRECTED FOR GRAPHIC

THE SEVERE WEATHER THREAT FOR TORNADO WATCH 40 CONTINUES.

INITIAL DISCRETE SUPERCELL WITH A HISTORY OF PERIODIC BRIEF TORNADO
TOUCHDOWNS WILL BE THE PRIMARY NEAR-TERM SEVERE THREAT INVOF
RENO/HARVEY/MCPHERSON COUNTIES KS. ADDITIONAL TSTM DEVELOPMENT
APPEARS TO BE UNDERWAY AS COLD FRONT HAS OVERTAKEN THE DRYLINE INTO
NWRN OK. ALTHOUGH CONVECTION SHOULD TRANSITION TO A LARGELY LINEAR
MODE...VERY STRONG SHEAR WILL BE FAVORABLE FOR AN INCREASING RISK OF
DAMAGING WINDS...WITH PERHAPS AN ADDITIONAL TORNADO OR TWO. A NEW WW
MAY BE NEEDED FOR PARTS OF OK.

01Z SURFACE ANALYSIS INDICATES THE PACIFIC COLD FRONT HAS OVERTAKEN
THE DRYLINE ACROSS CNTRL KS INTO FAR NWRN OK...RESULTING IN A
SUBSTANTIAL INCREASE IN CONVERGENCE. THIS HAS YIELDED A RAPID
INCREASE IN TSTM COVERAGE ALONG THE BOUNDARY. MEANWHILE...A COUPLE
OF DISCRETE STORMS HAVE PERSISTED AHEAD OF THE DRYLINE INVOF HUT.
ALTHOUGH THE 00Z OUN RAOB WAS QUITE CAPPED...MODIFIED TOP RAOB
SUGGESTS INSTABILITY IS WEAK /MLCAPE NEAR 500 J/KG/ BUT SUFFICIENT
FOR TORNADO AND DAMAGING WIND THREATS GIVEN PRESENCE OF EFFECTIVE
SRH AOA 400 M2/S2. CONTINUED BOUNDARY LAYER MOIST ADVECTION SHOULD
SUPPORT THESE RISKS WITHIN ONE OR MORE PROBABLE LINE-SEGMENTS
PROPAGATING QUICKLY E/SEWD THIS EVENING.

..GRAMS.. 02/29/2012

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

ATTN...WFO...TSA...TOP...ICT...OUN...DDC...

LAT...LON   37609859 37949833 38439760 38609683 38669600 38429574
            37449580 36669616 35969656 35729739 35899852 36349887
            37609859

SPC that day

Everything else SPC issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Feb 28, 7:59 PM CST	Mesoscale Discussion	SPC	Clay, Cloud, Jewell, Mitchell, Osborne, Ottawa and 5 more	31 min
Feb 28, 8:10 PM CST	Tornado Watch	SPC	Allen, Anderson, Brown, Butler, Chase, Chautauqua and 25 more	5 hr
Feb 28, 9:47 PM CST	Mesoscale Discussion	SPC	Allen, Anderson, Bourbon, Cherokee, Crawford, Franklin and 9 more	58 min
Feb 28, 10:07 PM CST	Severe Thunderstorm Watch	SPC	Johnson, Linn, Miami, Wyandotte	3 hr
Feb 28, 10:30 PM CST	Tornado Watch	SPC	Bourbon, Cherokee, Crawford	6 hr
Feb 28, 11:40 PM CST	Mesoscale Discussion	SPC	Adair, Cherokee, Delaware, Mayes, Muskogee, Ottawa and 1 more	95 min

Nearby

Mesoscale Discussions in Kansas, 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.