Alert archive / Kansas / Mesoscale Discussions in 2012

Mesoscale Discussion 139

February 20, 20126 counties in Kansas; 6 counties in Nebraska

The Storm Prediction Center issued this mesoscale discussion at Feb 20, 2012, 5:33 PM CST for 6 counties in Kansas; 6 counties in Nebraska. It was in force for 57 min.

The area

The outline as issued.

The facts

Issued: Feb 20, 2012, 5:33 PM CST (23:33 UTC)
Expired: Feb 20, 2012, 6:30 PM CST
In force: 57 min
Issued by: the Storm Prediction Center

Counties Clay County, KS, Cloud County, KS, Marshall County, KS, Republic County, KS, Riley County, KS, Washington County, KS, Clay County, NE, Fillmore County, NE, Jefferson County, NE, Nuckolls County, NE, Saline County, NE, Thayer County, NE

The radar

The Grand Island radar (KUEX), 99 km from the middle of the area, began a volume at 23:33 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

Omaha, NE (KOAX), launched 12:00Z, 11.6 hours before the alert went out and 157 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: 0 J/kg
Mixed-layer CIN: No buoyant parcel
Mixed-layer LCL: 979 m above ground
0-6 km bulk shear: 37 kt
0-1 km storm-relative helicity: 307 m²/s²
0-3 km storm-relative helicity: 270 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.

211 
ACUS11 KWNS 202334
SWOMCD
SPC MCD 202333
KSZ000-NEZ000-210030-

MESOSCALE DISCUSSION 0139
NWS STORM PREDICTION CENTER NORMAN OK
0533 PM CST MON FEB 20 2012

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

CONCERNING...SEVERE POTENTIAL...WATCH UNLIKELY

VALID 202333Z - 210030Z

ISOLATED SVR THUNDERSTORMS POSING A THREAT FOR LARGE HAIL...STRONG
GUSTY WINDS AND POSSIBLY A BRIEF TORNADO WILL BE POSSIBLE DURING THE
NEXT HR OR TWO OVER N-CNTRL KS AND S-CNTRL/SERN NEB. SVR WEATHER
THREAT IS EXPECTED TO BE TOO MARGINAL FOR A WW.

SUBJECTIVE SURFACE ANALYSIS PLACES AN AREA OF LOW PRESSURE OVER FAR
N-CNTRL KS AT 23Z...WITH A COLD FRONT EXTENDING SWD ACROSS CNTRL KS
INTO NRN OK. THUNDERSTORMS HAVE RECENTLY DEVELOPED AND INTENSIFIED
INVOF THE LOW...WHERE LAPSE RATES ARE STEEP BUT BOUNDARY LAYER
MOISTURE IS WEAK /I.E. LOW 40S SURFACE DEWPOINTS/...WHICH YIELDS
SBCAPE VALUES AOB 500 J/KG. NEVERTHELESS...STORMS MAY POSE A
MARGINAL SVR WEATHER THREAT DURING THE NEXT HR OR TWO BEFORE THE
BOUNDARY LAYER QUICKLY COOLS AND GREATLY REDUCES SURFACE BASED
INSTABILITY. THE PRIMARY THREAT WITH THESE STORMS WILL BE SVR HAIL
/AROUND 1 IN. DIAMETER/ AND STRONG GUSTY WINDS. IN
ADDITION...VERTICAL VORTICITY MAXIMIZED NEAR THE SURFACE LOW
SUGGESTS THE THREAT FOR A BRIEF TORNADO IS NON-ZERO.

..GARNER.. 02/20/2012

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

ATTN...WFO...OAX...TOP...GID...

LAT...LON   40839750 40359681 39889649 39339656 39119708 39139763
            40599831 40909796 40839750

SPC that day

Everything else SPC issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Feb 20, 1:39 PM CST	Mesoscale Discussion	SPC	Barber, Barton, Butler, Cowley, Ellsworth, Harper and 11 more	66 min
Feb 20, 2:50 PM CST	Severe Thunderstorm Watch	SPC	Butler, Chase, Chautauqua, Cowley, Elk, Greenwood and 8 more	4 hr
Feb 20, 4:50 PM CST	Mesoscale Discussion	SPC	Allen, Bourbon, Cherokee, Crawford, Labette, Montgomery and 3 more	55 min
Feb 20, 5:01 PM CST	Severe Thunderstorm Watch	SPC	Allen, Bourbon, Cherokee, Crawford, Labette, Montgomery and 3 more	4 hr
Feb 20, 5:37 PM CST	Mesoscale Discussion	SPC	Allen, Anderson, Bourbon, Chautauqua, Cherokee, Coffey and 20 more	113 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.