Alert archive / Kansas / Mesoscale Discussions in 2011

Mesoscale Discussion 828

May 20, 201117 counties in Kansas; 8 counties in Nebraska; 4 counties in Oklahoma

The Storm Prediction Center issued this mesoscale discussion at May 20, 2011, 1:52 PM CDT for 17 counties in Kansas; 8 counties in Nebraska; 4 counties in Oklahoma. It was in force for 113 min.

The area

The outline as issued.

The facts

Issued
May 20, 2011, 1:52 PM CDT (18:52 UTC)
Expired
May 20, 2011, 3:45 PM CDT
In force
113 min
Issued by
the Storm Prediction Center
All 29 counties

Barber County, KS, Barton County, KS, Comanche County, KS, Edwards County, KS, Ellsworth County, KS, Jewell County, KS, Kiowa County, KS, Lincoln County, KS, Mitchell County, KS, Osborne County, KS, Pawnee County, KS, Pratt County, KS, Rice County, KS, Rush County, KS, Russell County, KS, Smith County, KS, Stafford County, KS, Adams County, NE, Buffalo County, NE, Clay County, NE, Franklin County, NE, Hall County, NE, Kearney County, NE, Nuckolls County, NE, Webster County, NE, Ellis County, OK, Harper County, OK, Woods County, OK, Woodward County, OK

The radar

The Dodge City radar (KDDC), 122 km from the middle of the area, began a volume at 18:55 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

Dodge City, (KDDC), launched 12:00Z, 6.9 hours before the alert went out and 117 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, Dodge City, at 12:00Z on 2011-05-20Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 0 joules per kilogram.LCL10008507005003002001001 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, Dodge City, at 12:00Z on 2011-05-20The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity -59 square meters per square second.1939587897Sfc1 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
0 J/kg
Mixed-layer CIN
No buoyant parcel
Mixed-layer LCL
3052 m above ground
0-6 km bulk shear
58 kt
0-1 km storm-relative helicity
-59 m²/s²
0-3 km storm-relative helicity
27 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.

877 
ACUS11 KWNS 201853
SWOMCD
SPC MCD 201852
KSZ000-NEZ000-OKZ000-202045-

MESOSCALE DISCUSSION 0828
NWS STORM PREDICTION CENTER NORMAN OK
0152 PM CDT FRI MAY 20 2011

AREAS AFFECTED...CNTRL KS...S-CNTRL NEB...NWRN OK

CONCERNING...SEVERE POTENTIAL...SEVERE THUNDERSTORM WATCH LIKELY

VALID 201852Z - 202045Z

CONTINUED DESTABILIZATION ALONG COLD FRONT WILL HELP FOSTER TSTM
DEVELOPMENT THIS AFTERNOON WITH PRIMARY INITIAL RISK OF SEVERE HAIL.
THE PROBABILITY OF A SEVERE TSTM WATCH BEING ISSUED BY 21Z IS 60
PERCENT.

18Z SUBJECTIVE SURFACE ANALYSIS PLACED A PAIR OF 1003 MB CYCLONES
NEAR RSL AND 30 NNW GAG ALONG A N/S-ORIENTED COLD FRONT FROM THE
CNTRL INTO THE SRN PLAINS. SURFACE HEATING HAS BECOME MORE ROBUST
DURING THE PAST COUPLE OF HOURS AS AN EXPANSIVE CIRRUS CANOPY
ASSOCIATED WITH A LARGE-SCALE MCS OVER THE ERN GREAT PLAINS HAS
GRADUALLY SHIFTED EWD. A NARROW AXIS OF A MARGINALLY UNSTABLE AIR
MASS WITH MLCAPE AROUND 500 J/KG HAS DEVELOPED IMMEDIATELY AHEAD OF
THE COLD FRONT WHERE SURFACE TEMPERATURES HAVE WARMED INTO THE
MIDDLE 70S.

SHOWERS/TSTMS HAVE RECENTLY COMMENCED ALONG THE FRONT FROM CNTRL KS
INTO W-CNTRL OK...AN HOUR OR TWO EARLIER THAN LATEST
CONVECTION-ALLOWING HRRR AND WRF-NMM/NSSL GUIDANCE. CONTINUED
DESTABILIZATION WILL SUPPORT INCREASINGLY BUOYANT UPDRAFTS THROUGH
THE AFTERNOON AMIDST STRONG DEEP-LAYER SPEED SHEAR.
HOWEVER...VEER-BACK-VEER WIND PROFILES INDICATED IN AREA
PROFILERS...ALONG WITH WEAK LOW-LEVEL FLOW AND DEEP-LAYER SHEAR
VECTORS ORIENTED NEARLY PARALLEL TO THE INITIATING BOUNDARY SHOULD
RESULT IN A MORE CLUSTER TYPE CONVECTIVE MODE AND SERVE TO TEMPER A
MORE WIDESPREAD LARGE HAIL THREAT.

..GRAMS.. 05/20/2011

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

ATTN...WFO...TOP...ICT...OUN...GID...DDC...

LAT...LON   37209980 38849927 40699918 41049909 41219865 41059823
            40469798 38799791 36319878 36059918 36109971 36609990
            37209980

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
May 19, 8:17 PM CDTMesoscale DiscussionSPCBarber, Barton, Clark, Clay, Cloud, Comanche and 29 more118 min
May 19, 8:46 PM CDTTornado WatchSPCBarber, Barton, Clark, Clay, Cloud, Comanche and 34 more6 hr
May 19, 11:13 PM CDTMesoscale DiscussionSPCBarber, Barton, Clark, Clay, Cloud, Comanche and 29 more2 hr
May 20, 9:11 AM CDTMesoscale DiscussionSPCAllen, Anderson, Bourbon, Cherokee, Crawford, Douglas and 9 more2 hr
May 20, 2:32 PM CDTSevere Thunderstorm WatchSPCBarber, Barton, Clark, Clay, Cloud, Comanche and 30 more7 hr
May 20, 6:01 PM CDTMesoscale DiscussionSPCBarber, Barton, Clay, Cloud, Comanche, Edwards and 27 more59 min
May 19, 7:47 PM CDTMesoscale DiscussionSPCCaddo, Canadian, Comanche, Cotton, Grady, Kiowa and 1 more118 min
May 19, 11:39 PM CDTSevere Thunderstorm WatchSPCHarmon, Jackson, Tillman6 hr
May 20, 2:58 AM CDTMesoscale DiscussionSPCComanche, Jackson, Kiowa, Tillman, Washita92 min
May 20, 10:30 AM CDTMesoscale DiscussionSPCBryan, Choctaw, Haskell, Latimer, LeFlore, McCurtain and 2 more60 min
May 20, 11:03 AM CDTTornado WatchSPCAdair, Choctaw, Haskell, Latimer, LeFlore, McCurtain and 2 more7 hr
May 20, 1:28 PM CDTMesoscale DiscussionSPCAdair, Cherokee, Choctaw, Haskell, Latimer, LeFlore and 3 more62 min
May 20, 4:00 PM CDTMesoscale DiscussionSPCChoctaw, LeFlore, McCurtain, Pushmataha60 min
May 20, 5:56 PM CDTTornado WatchSPCMcCurtain3 hr

Nearby

Mesoscale Discussions in Kansas, 2011Mesoscale Discussions in Nebraska, 2011Mesoscale Discussions in Oklahoma, 2011Every mesoscale discussion in 2011

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.