Alert archive / Kansas / Mesoscale Discussions in 2012

Mesoscale Discussion 498

April 12, 2012Phillips County, Yuma County, Colorado; 15 counties in Kansas; Chase County, Dundy County, Hitchcock County, Nebraska

The Storm Prediction Center issued this mesoscale discussion at Apr 12, 2012, 12:24 PM MDT for Phillips County, Yuma County, Colorado; 15 counties in Kansas; Chase County, Dundy County, Hitchcock County, Nebraska. It was in force for 2 hr.

The area

The outline as issued.

The facts

Issued
Apr 12, 2012, 12:24 PM MDT (18:24 UTC)
Expired
Apr 12, 2012, 2:30 PM MDT
In force
2 hr
Issued by
the Storm Prediction Center

Counties Phillips County, CO, Yuma County, CO, Cheyenne County, KS, Decatur County, KS, Finney County, KS, Gove County, KS, Greeley County, KS, Kearny 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, Chase County, NE, Dundy County, NE, Hitchcock County, NE

The radar

The Goodland radar (KGLD), 27 km from the middle of the area, began a volume at 18:25 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

Denver, CO (KDNR), launched 12:00Z, 6.4 hours before the alert went out and 165 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, Denver, CO at 12:00Z on 2012-04-12Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 34 joules per kilogram.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 km-30°-20°-10°0°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Denver, CO at 12:00Z on 2012-04-12The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 201 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
34 J/kg
Mixed-layer CIN
-126 J/kg
Mixed-layer LCL
946 m above ground
0-6 km bulk shear
50 kt
0-1 km storm-relative helicity
201 m²/s²
0-3 km storm-relative helicity
121 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.

836 
ACUS11 KWNS 121825
SWOMCD
SPC MCD 121824
KSZ000-NEZ000-COZ000-122030-

MESOSCALE DISCUSSION 0498
NWS STORM PREDICTION CENTER NORMAN OK
0124 PM CDT THU APR 12 2012

AREAS AFFECTED...NERN CO...SWRN NEB THROUGH WRN KS

CONCERNING...SEVERE POTENTIAL...WATCH LIKELY

VALID 121824Z - 122030Z

ISOLATED SUPERCELLS ARE EXPECTED TO INITIATE BY 20Z OVER NERN CO.
ACTIVITY WILL THEN DEVELOP INTO SWRN NEB AND WRN KS THIS EVENING.
PRIMARY THREATS WILL BE VERY LARGE HAIL AND ISOLATED TORNADOES.

EARLY THIS AFTERNOON A DRYLINE EXTENDS SWD THROUGH ERN CO FROM A
WEAK SFC LOW IN NERN CO. A WARM FRONT/DIFFERENTIAL HEATING BOUNDARY
STRETCHED FROM NERN CO SEWD THROUGH WRN KS. A NE-SW ORIENTED
BOUNDARY WITH DEVELOPING CUMULUS WAS INDICATED JUST WEST OF AKRON.
LOW CLOUDS ARE MIXING OUT SOUTH AND WEST OF THE WARM FRONT ALLOWING
FOR DESTABILIZATION WITHIN THE MOIST WARM SECTOR. THE CAPPING
INVERSION WILL ERODE NEXT COUPLE HOURS PROMOTED BY SFC HEATING AND
MIXING AS WELL AS DEEPER FORCING FOR ASCENT ACCOMPANYING A NEWD
EJECTING SHORTWAVE TROUGH THAT WILL INTERACT WITH WRN FRINGE OF
MOIST AXIS. HIGH BASED STORMS MAY SOON DEVELOP IN THE DRIER AIR OVER
NE CO ALONG THE NE-SW BOUNDARY. DEEP LAYER VERTICAL SHEAR OF 40-50
KT WILL SUPPORT SUPERCELLS. OTHER STORMS MAY DEVELOP FARTHER EWD
ALONG DRYLINE...AND AS THEY MOVE THROUGH THE MOIST AXIS THEY WILL
ENCOUNTER SOMEWHAT LOWER LCLS AND INCREASINGLY FAVORABLE HODOGRAPHS
ASSOCIATED WITH STRENGTHENING LLJ. STORMS MAY EVENTUALLY INTERACT
WITH THE NW-SE ORIENTED WARM FRONT FROM EXTREME NE CO...SWRN NEB
INTO WRN KS WHERE 0-1 KM STORM RELATIVE HELICITY WILL BE MAXIMIZED
THIS EVENING.

..DIAL.. 04/12/2012

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

ATTN...WFO...LBF...DDC...GLD...BOU...

LAT...LON   37700146 38830208 39820252 40650313 40920193 40300054
            38760016 37760063 37700146

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Apr 11, 10:50 PM MDTMesoscale DiscussionSPCCrowley, Douglas, Elbert, El Paso, Jefferson, Pueblo and 1 more85 min
Apr 12, 12:47 PM MDTTornado WatchSPCCheyenne, Kiowa, Kit Carson, Logan, Phillips, Prowers and 3 more7 hr
Apr 12, 4:02 PM MDTMesoscale DiscussionSPCCheyenne, Kit Carson, Phillips, Prowers, Sedgwick, Washington and 1 more88 min
Apr 12, 1:28 PM MDTMesoscale DiscussionSPCGrant, Haskell, Meade, Seward, Stevens2 hr
Apr 12, 5:54 PM MDTSevere Thunderstorm WatchSPCBlaine, Buffalo, Custer, Dawson, Franklin, Furnas and 12 more6 hr

Nearby

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