Alert archive / Nebraska / Mesoscale Discussions in 2012

Mesoscale Discussion 1229

June 19, 20126 counties in Nebraska; Bennett County, South Dakota

The Storm Prediction Center issued this mesoscale discussion at Jun 19, 2012, 10:59 PM MDT for 6 counties in Nebraska; Bennett County, South Dakota. It was in force for 91 min.

The area

The outline as issued.

The facts

Issued: Jun 19, 2012, 10:59 PM MDT (04:59 UTC)
Expired: Jun 20, 2012, 12:30 AM MDT
In force: 91 min
Issued by: the Storm Prediction Center
Chance of a watch: 40%

Counties Box Butte County, NE, Dawes County, NE, Garden County, NE, Grant County, NE, Morrill County, NE, Sheridan County, NE, Bennett County, SD

The radar

The North Platte radar (KLNX), 153 km from the middle of the area, began a volume at 05:02 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.

Severe Thunderstorm Watch 416Jun 19, 11:55 PM MDT

The nearest sounding before it

Rapid City, SD (KUNR), launched 00:00Z, 5.0 hours before the alert went out and 195 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: 1667 m above ground
0-6 km bulk shear: 87 kt
0-1 km storm-relative helicity: 3 m²/s²
0-3 km storm-relative helicity: 323 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.

143 
ACUS11 KWNS 200500
SWOMCD
SPC MCD 200459
NEZ000-SDZ000-200630-

MESOSCALE DISCUSSION 1229
NWS STORM PREDICTION CENTER NORMAN OK
1159 PM CDT TUE JUN 19 2012

AREAS AFFECTED...PARTS OF  WESTERN NEBRASKA/NEBRASKA PANHANDLE AND
SOUTHWESTERN SOUTH DAKOTA

CONCERNING...SEVERE POTENTIAL...WATCH POSSIBLE

VALID 200459Z - 200630Z

PROBABILITY OF WATCH ISSUANCE...40 PERCENT

SUMMARY...THE NEED FOR A WATCH IS NOT CERTAIN...BUT TRENDS ARE BEING
MONITORED FOR AN INCREASING SEVERE THREAT THAT COULD REQUIRE A WATCH
WITHIN THE NEXT HOUR OR TWO.

DISCUSSION...MOISTURE WITHIN A NORTHEASTERLY POST-FRONTAL LOW-LEVEL
FLOW ACROSS CENTRAL/WESTERN SOUTH DAKOTA INTO WESTERN NEBRASKA
REMAINS SUFFICIENT TO SUPPORT AT LEAST WEAK CAPE...BENEATH STEEP
LAPSE RATES ALOFT.  AND THIS APPEARS LIKELY TO MAINTAIN A DEVELOPING
CLUSTER OF STORMS SPREADING NORTHEASTWARD WITH MID/UPPER FORCING OUT
OF SOUTHEASTERN WYOMING.  DEEP LAYER SHEAR...ASSOCIATED WITH VEERING
OF MODERATE NORTHEASTERLY NEAR SURFACE FLOW TO 30-40 KT OUT OF THE
SOUTHWEST AT 500 MB...IS VERY STRONG...AND COUPLED WITH SIZABLE
SUB-CLOUD TEMPERATURE/DEW POINT SPREADS...AN ORGANIZED STRONG WIND
EVENT COULD CONTINUE TO EVOLVE THROUGH THE 06-09Z TIME FRAME.

..KERR/CARBIN.. 06/20/2012

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

ATTN...WFO...LBF...UNR...CYS...

LAT...LON   43020330 43400166 42910111 42250099 41630153 41400249
            41690327 41940347 43020330

SPC that day

Everything else SPC issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Jun 19, 6:01 PM MDT	Severe Thunderstorm Watch	SPC	Antelope, Blaine, Boyd, Brown, Cedar, Custer and 15 more	7 hr
Jun 19, 7:50 PM MDT	Mesoscale Discussion	SPC	Arthur, Box Butte, Cherry, Dawes, Garden, Grant and 7 more	85 min
Jun 19, 11:57 PM MDT	Severe Thunderstorm Watch	SPC	Blaine, Boyd, Brown, Cherry, Garden, Grant and 7 more	3 hr
Jun 20, 3:00 AM MDT	Mesoscale Discussion	SPC	Arthur, Blaine, Boyd, Brown, Cherry, Garden and 8 more	60 min
Jun 20, 2:24 PM MDT	Mesoscale Discussion	SPC	Adams, Burt, Butler, Cass, Clay, Dodge and 21 more	96 min
Jun 19, 8:12 PM MDT	Mesoscale Discussion	SPC	Brookings, Deuel, Grant, Hamlin, Kingsbury, Lake and 3 more	93 min
Jun 19, 10:20 PM MDT	Severe Thunderstorm Watch	SPC	Aurora, Beadle, Brookings, Brule, Buffalo, Charles Mix and 25 more	5 hr

Nearby

Mesoscale Discussions in Nebraska, 2012 Mesoscale Discussions in South Dakota, 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.