Alert archive / Nebraska / Mesoscale Discussions in 2016

Mesoscale Discussion 1007

June 21, 201610 counties in Nebraska; 7 counties in South Dakota; Crook County, Goshen County, Weston County, Wyoming

The Storm Prediction Center issued this mesoscale discussion at Jun 21, 2016, 2:27 PM MDT for 10 counties in Nebraska; 7 counties in South Dakota; Crook County, Goshen County, Weston County, Wyoming. It was in force for 2 hr.

The area

The outline as issued.

The facts

Issued: Jun 21, 2016, 2:27 PM MDT (20:27 UTC)
Expired: Jun 21, 2016, 4:30 PM MDT
In force: 2 hr
Issued by: the Storm Prediction Center
Chance of a watch: 40%

Counties Banner County, NE, Box Butte County, NE, Cheyenne County, NE, Dawes County, NE, Garden County, NE, Kimball County, NE, Morrill County, NE, Scotts Bluff County, NE, Sheridan County, NE, Sioux County, NE, Butte County, SD, Custer County, SD, Fall River County, SD, Lawrence County, SD, Meade County, SD, Oglala Lakota County, SD, Pennington County, SD, Crook County, WY, Goshen County, WY, Weston County, WY

The radar

The Rapid City radar (KUDX), 95 km from the middle of the area, began a volume at 20:27 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 281Jun 21, 3:45 PM MDT

The nearest sounding before it

Rapid City, SD (KRAP), launched 12:00Z, 8.5 hours before the alert went out and 87 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: 1 J/kg
Mixed-layer CIN: -730 J/kg
Mixed-layer LCL: 1912 m above ground
0-6 km bulk shear: 42 kt
0-1 km storm-relative helicity: 84 m²/s²
0-3 km storm-relative helicity: 143 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

The text

As transmitted.

717 
ACUS11 KWNS 212028
SWOMCD
SPC MCD 212027 
NEZ000-SDZ000-MTZ000-WYZ000-212230-

MESOSCALE DISCUSSION 1007
NWS STORM PREDICTION CENTER NORMAN OK
0327 PM CDT TUE JUN 21 2016

AREAS AFFECTED...FAR ERN WY...FAR SE MT...WRN SD AND THE NEB
PANHANDLE

CONCERNING...SEVERE POTENTIAL...WATCH POSSIBLE 

VALID 212027Z - 212230Z

PROBABILITY OF WATCH ISSUANCE...40 PERCENT

SUMMARY...ISOLATED STRONG TO SEVERE STORMS MAY PRODUCE STRONG WIND
GUSTS AND HAIL INTO THE EVENING HOURS. A WATCH DOES NOT APPEAR
IMMEDIATELY NECESSARY...BUT TRENDS WILL BE MONITORED CLOSELY FOR ANY
INCREASING SEVERE THREAT INTO THE EVENING HOURS.

DISCUSSION...ISOLATED THUNDERSTORMS HAVE DEVELOPED OVER NE WY IN
VICINITY OF SFC TROUGH AND LOW LEVEL UPSLOPE REGIME. AS THE STORMS
DEVELOP EASTWARD INTO WRN SD/NEB PANHANDLE...MOISTURE QUICKLY
INCREASES INTO THE MID 50S TO LOW 60S F. HOWEVER...CAPPING ALSO
INCREASES WITH EASTWARD EXTENT. THIS WILL LIKELY LIMIT MORE
WIDESPREAD/LONGER-LIVED SEVERE THREAT...BUT A FEW STRONG TO SEVERE
STORMS WILL BE POSSIBLE. DAMAGING WINDS WILL BE THE MAIN CONCERN
GIVEN LARGE TEMPERATURE-DEWPOINT SPREADS AND DCAPE GREATER THAN 1000
J/KG...THOUGH SOME HAIL IS ALSO POSSIBLE GIVEN FAVORABLE DEEP LAYER
SHEAR PROFILES AND STEEP MIDLEVEL LAPSE RATES. SOME HI-RES GUIDANCE
INDICATES SOME UPSCALE GROWTH IS POSSIBLE...BUT CONFIDENCE IS LOW IN
THIS SCENARIO GIVEN THE AFOREMENTIONED CAPPING PROBLEMS IN ADDITION
TO WEAKER FORCING FOR ASCENT AS THE UPPER SHORTWAVE TROUGH REMAINS
FURTHER NORTH ACROSS MT AND ND. A WATCH DOES NOT APPEAR IMMEDIATELY
NECESSARY BUT CONVECTIVE TRENDS WILL BE MONITORED INTO THE EVENING
FOR INCREASING SEVERE POTENTIAL.

..LEITMAN/GUYER.. 06/21/2016

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

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

LAT...LON   45040498 45510442 45510363 45230295 44550233 43690179
            42720179 41500209 41020248 41040375 41150422 41940463
            43320443 44550485 45040498

SPC that day

Everything else SPC issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Jun 20, 8:04 PM MDT	Mesoscale Discussion	SPC	Burt, Butler, Cass, Colfax, Cuming, Dodge and 19 more	56 min
Jun 21, 2:43 AM MDT	Mesoscale Discussion	SPC	Boone, Butler, Cass, Colfax, Dodge, Douglas and 10 more	3 hr
Jun 21, 3:46 PM MDT	Severe Thunderstorm Watch	SPC	Buffalo, Butte, Corson, Dewey, Faulk, Haakon and 18 more	7 hr

Nearby

Mesoscale Discussions in Nebraska, 2016 Mesoscale Discussions in South Dakota, 2016 Mesoscale Discussions in Wyoming, 2016 Every 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.