Alert archive / Kansas / Mesoscale Discussions in 2016

Mesoscale Discussion 1421

July 28, 201611 counties in Kansas; 6 counties in Nebraska

The Storm Prediction Center issued this mesoscale discussion at Jul 28, 2016, 1:59 PM CDT for 11 counties in Kansas; 6 counties in Nebraska. It was in force for 2 hr.

The area

The outline as issued.

The facts

Issued
Jul 28, 2016, 1:59 PM CDT (18:59 UTC)
Expired
Jul 28, 2016, 4:00 PM CDT
In force
2 hr
Issued by
the Storm Prediction Center
Chance of a watch
80%

Counties Decatur County, KS, Ellis County, KS, Graham County, KS, Lincoln County, KS, Mitchell County, KS, Norton County, KS, Osborne County, KS, Phillips County, KS, Rooks County, KS, Russell County, KS, Smith County, KS, Frontier County, NE, Furnas County, NE, Gosper County, NE, Harlan County, NE, Hitchcock County, NE, Red Willow County, NE

The radar

The Grand Island radar (KUEX), 130 km from the middle of the area, began a volume at 18:59 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

N. Platte/Lee Bi, NE (KLBF), launched 12:00Z, 7.0 hours before the alert went out and 182 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, N. Platte/Lee Bi, NE at 12:00Z on 2016-07-28Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 405 joules per kilogram.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, N. Platte/Lee Bi, NE at 12:00Z on 2016-07-28The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 4 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
405 J/kg
Mixed-layer CIN
-177 J/kg
Mixed-layer LCL
894 m above ground
0-6 km bulk shear
27 kt
0-1 km storm-relative helicity
4 m²/s²
0-3 km storm-relative helicity
66 m²/s²
Significant tornado parameter
0.0
Supercell composite
1.3

Open this sounding in Storm Lab

The text

As transmitted.

644 
ACUS11 KWNS 281900
SWOMCD
SPC MCD 281859 
KSZ000-NEZ000-282100-

MESOSCALE DISCUSSION 1421
NWS STORM PREDICTION CENTER NORMAN OK
0159 PM CDT THU JUL 28 2016

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

CONCERNING...SEVERE POTENTIAL...WATCH LIKELY 

VALID 281859Z - 282100Z

PROBABILITY OF WATCH ISSUANCE...80 PERCENT

SUMMARY...ONGOING MCS ACROSS SW NEB IS EXPECTED TO INTENSIFY AS IT
CONTINUES SEWD INTO A MORE UNSTABLE ENVIRONMENT. A WATCH WILL LIKELY
BE NEEDED TO COVER THE RESULTING THREAT FOR DAMAGING WIND GUSTS AND
HAIL.

DISCUSSION...RECENT SURFACE ANALYSIS PLACES AN ARCING OUTFLOW
BOUNDARY -- ASSOCIATED WITH EARLIER DECAYING CONVECTION ACROSS NW KS
-- FROM JUST NE OF LAA TO N OF GCK TO JUST W OF HLC. AIRMASS W OF
THIS BOUNDARY REMAINS LARGELY STABLE WHILE THE AIRMASS E HAS HEATED
INTO THE MID 80S AMIDST DEWPOINTS IN THE MID 60S. AS A RESULT...A
CORRIDOR OF INSTABILITY EXISTS E OF THE OUTFLOW BOUNDARY FROM
S-CNTRL NEB SEWD INTO CNTRL KS WITH RECENT MESOANALYSIS ESTIMATING
MLCAPE FROM 1500 TO 2000 J/KG.  ONGOING MCS ACROSS SW NEB IS
EXPECTED TO CONTINUE SEWD WITH THE ERN PORTION OF THE MCS
INTERACTING WITH THIS MORE UNSTABLE AIRMASS. 

THIS CORRIDOR IS ON THE ERN PERIPHERY OF THE BETTER FLOW ALOFT BUT
RECENT UEX AND GLD VADS BOTH SAMPLED 0-6 KM BULK SHEAR AROUND 40-45
KT. THIS KINEMATIC ENVIRONMENT IS SUPPORTIVE OF ORGANIZED STORM
STRUCTURES. CURRENT EXPECTATION IS FOR THE ONGOING MCS TO GRADUALLY
INTENSIFY AS IT CONTINUES SEWD WITH INCREASED THREAT FOR DAMAGING
WIND GUSTS AND HAIL. A WW WILL LIKELY BE NEEDED TO COVER THIS THREAT
WITHIN THE NEXT HOUR OR TWO.

..MOSIER/DIAL.. 07/28/2016

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

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

LAT...LON   39880083 40330130 40770046 40529957 39579802 39009793
            38609834 38589940 39310018 39880083

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Jul 27, 11:01 PM CDTMesoscale DiscussionSPCCheyenne, Finney, Gove, Greeley, Hamilton, Kearny and 9 more119 min
Jul 28, 3:20 PM CDTMesoscale DiscussionSPCChautauqua, Cowley, Harper, Sumner115 min
Jul 28, 3:46 PM CDTSevere Thunderstorm WatchSPCBarton, Butler, Chase, Chautauqua, Clay, Cloud and 45 more6 hr
Jul 28, 6:14 PM CDTMesoscale DiscussionSPCBarton, Butler, Chase, Clay, Cloud, Dickinson and 35 more2 hr
Jul 28, 10:43 AM CDTMesoscale DiscussionSPCArthur, Banner, Chase, Cheyenne, Deuel, Garden and 5 more92 min

Nearby

Mesoscale Discussions in Kansas, 2016Mesoscale Discussions in Nebraska, 2016Every mesoscale discussion in 2016

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.