Alert archive / Nebraska / Mesoscale Discussions in 2012

Mesoscale Discussion 1263

June 24, 20124 counties in Nebraska; Fall River County, Lawrence County, South Dakota; 4 counties in Wyoming

The Storm Prediction Center issued this mesoscale discussion at Jun 24, 2012, 5:36 PM MDT for 4 counties in Nebraska; Fall River County, Lawrence County, South Dakota; 4 counties in Wyoming. It was in force for 84 min.

The area

The outline as issued.

The facts

Issued
Jun 24, 2012, 5:36 PM MDT (23:36 UTC)
Expired
Jun 24, 2012, 7:00 PM MDT
In force
84 min
Issued by
the Storm Prediction Center
Chance of a watch
20%

Counties Banner County, NE, Kimball County, NE, Scotts Bluff County, NE, Sioux County, NE, Fall River County, SD, Lawrence County, SD, Crook County, WY, Goshen County, WY, Niobrara County, WY, Weston County, WY

The radar

The Rapid City radar (KUDX), 173 km from the middle of the area, began a volume at 23:39 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 nearest sounding before it

Rapid City, SD (KUNR), launched 12:00Z, 11.6 hours before the alert went out and 166 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, Rapid City, SD at 12:00Z on 2012-06-24Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 2549 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, Rapid City, SD at 12:00Z on 2012-06-24The 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
2549 J/kg
Mixed-layer CIN
-333 J/kg
Mixed-layer LCL
709 m above ground
0-6 km bulk shear
22 kt
0-1 km storm-relative helicity
4 m²/s²
0-3 km storm-relative helicity
229 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.

856 
ACUS11 KWNS 242337
SWOMCD
SPC MCD 242336
SDZ000-NEZ000-COZ000-WYZ000-250100-

MESOSCALE DISCUSSION 1263
NWS STORM PREDICTION CENTER NORMAN OK
0636 PM CDT SUN JUN 24 2012

AREAS AFFECTED...ERN WY THROUGH SWRN SD AND WRN NEB

CONCERNING...SEVERE POTENTIAL...WATCH UNLIKELY

VALID 242336Z - 250100Z

PROBABILITY OF WATCH ISSUANCE...20 PERCENT

SUMMARY...HIGH BASED STORMS DEVELOPING OVER ERN WY WILL POSE A
THREAT FOR ISOLATED DAMAGING WIND AND HAIL AS THEY PROPAGATE SLOWLY
EWD AND NEWD THROUGH MID EVENING. THE STRONGER STORMS ARE EXPECTED
TO REMAIN VERY ISOLATED...AND A WW WILL PROBABLY NOT BE NEEDED
UNLESS ACTIVITY BEGINS TO SHOW A SUBSTANTIAL INCREASE IN COVERAGE.

DISCUSSION...EARLY THIS EVENING HIGH BASED STORMS ARE DEVELOPING
ALONG AND JUST EAST OF THE HIGHER TERRAIN OF WY AND WHERE DEEP
MIXING HAS WEAKENED THE CAP. DEEP INVERTED-V BOUNDARY LAYERS WILL
SUPPORT ISOLATED DOWNBURSTS WITHIN THE STRONGER CORES. ELY LOW LEVEL
WINDS TO THE EAST OF A N-S ORIENTED BOUNDARY WILL SUPPORT EWD
PROPAGATION INTO THE MORE UNSTABLE AIR LOCATED OVER WRN NEB AND SWRN
SD. HOWEVER...THE BOUNDARY LAYER IS ALSO MORE CAPPED WITH EWD EXTENT
INTO THE HIGH PLAINS. THIS IN CONJUNCTION WITH BUILDING RIDGE
SUGGEST THAT STORMS MAY NOT BE ABLE TO PERSIST VERY LONG AS THEY
ADVANCE INTO WRN NEB AND SWRN SD...ESPECIALLY AS THE BOUNDARY LAYER
BEGINS TO COOL. IN THE MEANTIME...STORMS THAT CAN INITIATE WILL POSE
A THREAT FOR ISOLATED DOWNBURSTS AND LARGE HAIL. DURATION AND
COVERAGE OF STORMS WILL PROBABLY NOT NECESSITATE A WW...BUT AREA
WILL CONTINUE TO BE MONITORED.

..DIAL/MEAD.. 06/24/2012

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

ATTN...WFO...UNR...BOU...CYS...

LAT...LON   44660381 42700331 41180348 40960433 41500465 42770478
            44670491 44660381

Nearby

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