Alert archive / Kansas / Severe Thunderstorm Watches in 2012

Severe Thunderstorm Watch 587

August 23, 201230 counties in Kansas

The Storm Prediction Center issued this severe thunderstorm watch at Aug 23, 2012, 5:57 PM CDT for 30 counties in Kansas. It was in force for 4 hr.

The area

The outline as issued.

The facts

Issued
Aug 23, 2012, 5:57 PM CDT (22:57 UTC)
Expired
Aug 23, 2012, 10:08 PM CDT
In force
4 hr
Issued by
the Storm Prediction Center
Largest hail expected
2 in
Strongest gust expected
55 kt
All 30 counties

Barton County, KS, Cheyenne County, KS, Decatur County, KS, Ellis County, KS, Finney County, KS, Gove County, KS, Graham County, KS, Greeley County, KS, Hamilton County, KS, Hodgeman County, KS, Kearny County, KS, Lane County, KS, Logan County, KS, Ness County, KS, Norton County, KS, Osborne County, KS, Pawnee County, KS, Phillips County, KS, Rawlins County, KS, Rooks County, KS, Rush County, KS, Russell County, KS, Scott County, KS, Sheridan County, KS, Sherman County, KS, Smith County, KS, Thomas County, KS, Trego County, KS, Wallace County, KS, Wichita County, KS

The radar

The Goodland radar (KGLD), 101 km from the middle of the area, began a volume at 22:57 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.

What SPC expected

The probabilities SPC published with the watch, for the watch area over its life.

Two or more tornadoes
10%
One or more EF2 to EF5 tornadoes
2%
Ten or more severe wind reports
30%
One or more gusts of 65 knots or more
10%
Ten or more severe hail reports
40%
One or more hailstones of 2 inches or more
10%
Six or more combined severe hail and wind reports
60%

Warnings issued inside it

1 tornado, severe thunderstorm and flash flood warnings for its counties while it was in force.

IssuedProductOfficeCountiesLasted
Aug 23, 7:20 PM CDTSevere Thunderstorm WarningGLDGove, Logan, Sheridan, Thomas40 min

Discussions around it

SPC mesoscale discussions over the same counties from four hours before the watch to its end.

The nearest sounding before it

Dodge City, (KDDC), launched 12:00Z, 11.0 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-pSkew-T log-p diagram, Dodge City, at 12:00Z on 2012-08-23Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 1075 joules per kilogram.LCLLFCEL10008507005003002001001 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 2012-08-23The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 221 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
1075 J/kg
Mixed-layer CIN
-184 J/kg
Mixed-layer LCL
897 m above ground
0-6 km bulk shear
17 kt
0-1 km storm-relative helicity
221 m²/s²
0-3 km storm-relative helicity
332 m²/s²
Significant tornado parameter
0.0
Supercell composite
3.0

Open this sounding in Storm Lab

The text

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

971 
WWUS20 KWNS 232300
SEL7  
SPC WW 232300
KSZ000-240600-

URGENT - IMMEDIATE BROADCAST REQUESTED
SEVERE THUNDERSTORM WATCH NUMBER 587
NWS STORM PREDICTION CENTER NORMAN OK
600 PM CDT THU AUG 23 2012

THE NWS STORM PREDICTION CENTER HAS ISSUED A
SEVERE THUNDERSTORM WATCH FOR PORTIONS OF 

       WESTERN KANSAS

EFFECTIVE THIS THURSDAY NIGHT AND FRIDAY MORNING FROM 600 PM
UNTIL 100 AM CDT.

HAIL TO 2 INCHES IN DIAMETER...THUNDERSTORM WIND GUSTS TO 65
MPH...AND DANGEROUS LIGHTNING ARE POSSIBLE IN THESE AREAS.

THE SEVERE THUNDERSTORM WATCH AREA IS APPROXIMATELY ALONG AND 80
STATUTE MILES EAST AND WEST OF A LINE FROM 45 MILES NORTH
NORTHWEST OF HILL CITY KANSAS TO 20 MILES SOUTHEAST OF GARDEN
CITY KANSAS.  FOR A COMPLETE DEPICTION OF THE WATCH SEE THE
ASSOCIATED WATCH OUTLINE UPDATE (WOUS64 KWNS WOU7).

REMEMBER...A SEVERE THUNDERSTORM WATCH MEANS CONDITIONS ARE
FAVORABLE FOR SEVERE THUNDERSTORMS IN AND CLOSE TO THE WATCH
AREA. PERSONS IN THESE AREAS SHOULD BE ON THE LOOKOUT FOR
THREATENING WEATHER CONDITIONS AND LISTEN FOR LATER STATEMENTS
AND POSSIBLE WARNINGS. SEVERE THUNDERSTORMS CAN AND OCCASIONALLY
DO PRODUCE TORNADOES.

DISCUSSION...STORMS ARE GRADUALLY INCREASING OVER WRN/NORTH CENTRAL
KS NEAR A LOW LEVEL CONVERGENCE ZONE EXTENDING FROM A LOW OVER SERN
CO NEWD INTO NWRN KS.  THE AIR MASS SOUTH OF THE FRONT IS WARM AND
UNSTABLE WITH MLCAPE AROUND 1500 J/KG.  ALTHOUGH MID LEVEL WINDS ARE
MODEST AT BEST...STRONG DIRECTIONAL SHEAR WITH HEIGHT WILL ENHANCE
STORM ORGANIZATION AND INTENSITY WITH ORGANIZED MULTICELL STRUCTURES
LIKELY.  AN INCREASE STORM COVERAGE IS EXPECTED THIS EVENING AS A
LOW LEVEL JET DEVELOPS INTO WRN KS AND THIS MAY AID IN STORM
MAINTENANCE INTO THE OVERNIGHT HOURS.  LARGE HAIL AND STRONG WIND
GUSTS WILL BE POSSIBLE WITH STRONGER CELLS...AND SLOW STORM MOTION
SUGGEST ADDITIONAL THREAT OF LOCALIZED HEAVY RAIN.

AVIATION...A FEW SEVERE THUNDERSTORMS WITH HAIL SURFACE AND ALOFT
TO 2 INCHES. EXTREME TURBULENCE AND SURFACE WIND GUSTS TO 55
KNOTS. A FEW CUMULONIMBI WITH MAXIMUM TOPS TO 450. MEAN STORM
MOTION VECTOR 28015.


...WEISS

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Aug 23, 3:20 PM CDTMesoscale DiscussionSPCDecatur, Finney, Gove, Graham, Grant, Gray and 19 more55 min

Nearby

Severe Thunderstorm Watches in Kansas, 2012Every severe thunderstorm watch 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.