Alert archive / North Dakota / Mesoscale Discussions in 2016

Mesoscale Discussion 877

June 11, 20166 counties in North Dakota; Corson County, Harding County, Perkins County, South Dakota

The Storm Prediction Center issued this mesoscale discussion at Jun 11, 2016, 5:18 PM MDT for 6 counties in North Dakota; Corson County, Harding County, Perkins County, South Dakota. It was in force for 117 min.

The area

The outline as issued.

The facts

Issued: Jun 11, 2016, 5:18 PM MDT (23:18 UTC)
Expired: Jun 11, 2016, 7:15 PM MDT
In force: 117 min
Issued by: the Storm Prediction Center
Chance of a watch: 60%

Counties Adams County, ND, Bowman County, ND, Grant County, ND, Hettinger County, ND, Sioux County, ND, Slope County, ND, Corson County, SD, Harding County, SD, Perkins County, SD

The radar

The Bismarck radar (KBIS), 163 km from the middle of the area, began a volume at 23:20 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 247Jun 11, 5:45 PM MDT

The nearest sounding before it

Bismarck Municip, ND (KBIS), launched 12:00Z, 11.3 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-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: 8 J/kg
Mixed-layer CIN: -622 J/kg
Mixed-layer LCL: 1742 m above ground
0-6 km bulk shear: 46 kt
0-1 km storm-relative helicity: 113 m²/s²
0-3 km storm-relative helicity: 399 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.1

Open this sounding in Storm Lab

The text

As transmitted.

698 
ACUS11 KWNS 112319
SWOMCD
SPC MCD 112318 
SDZ000-NDZ000-120115-

MESOSCALE DISCUSSION 0877
NWS STORM PREDICTION CENTER NORMAN OK
0618 PM CDT SAT JUN 11 2016

AREAS AFFECTED...PORTIONS OF NWRN SD...SWRN ND

CONCERNING...SEVERE POTENTIAL...WATCH POSSIBLE 

VALID 112318Z - 120115Z

PROBABILITY OF WATCH ISSUANCE...60 PERCENT

SUMMARY...AN INCREASING RISK FOR SVR TSTMS WITH LARGE HAIL...DMGG
WIND GUSTS...AND PERHAPS A TORNADO EXISTS ACROSS THE AREA...AND WW
ISSUANCE IS POSSIBLE.

DISCUSSION...CONVECTION EMANATING FROM THE DEEP BOUNDARY LAYER
ACROSS PARTS OF WRN SD IS ENTERING A CORRIDOR OF RICHER
BOUNDARY-LAYER MOISTURE CHARACTERIZED BY SFC DEWPOINTS IN THE MIDDLE
60S. MODIFICATIONS TO THE 21Z BIS SPECIAL RAOB TO ACCOUNT FOR
THERMODYNAMIC CONDITIONS WITHIN THE MOIST CORRIDOR AHEAD OF THE
CONVECTION SUGGEST STRONG INSTABILITY IN PLACE -- WITH MLCAPE AROUND
2000-3000 J/KG AND LITTLE MLCINH. THIS SUGGESTS THE POTENTIAL FOR
GRADUAL INTENSIFICATION OF CONVECTION DEVELOPING ACROSS NWRN
SD...THAT WILL SPREAD INTO A ZONE OF 35-50 KT OF EFFECTIVE BULK
SHEAR AS IT NEARS THE SD/ND BORDER. SUPERCELL CLUSTERS COULD RESULT
WITH SVR HAIL/WIND...AND POSSIBLY A TORNADO. SIGNIFICANTLY SVR HAIL
WILL BE POSSIBLE GIVEN THE STEEP LAPSE RATES SAMPLED BY THE RAOB --
AROUND 8.5 C/KM IN THE H7-H5 LAYER. WITH STRONGER DEEP ASCENT
DISPLACED TO THE W OF THE REGION...THERE IS SOME UNCERTAINTY
REGARDING CONVECTIVE/SVR COVERAGE...AND CONVECTIVE TRENDS WILL
CONTINUE TO BE MONITORED FOR WW ISSUANCE.

..COHEN/CORFIDI.. 06/11/2016

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

ATTN...WFO...ABR...BIS...UNR...

LAT...LON   45070204 45420335 46010392 46630361 46590200 46220106
            45350073 45070204

SPC that day

Everything else SPC issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Jun 11, 12:03 AM MDT	Mesoscale Discussion	SPC	Billings, Dunn, Mercer, Stark	87 min
Jun 11, 2:50 PM MDT	Mesoscale Discussion	SPC	Billings, Bowman, Golden Valley, McKenzie, Slope, Williams	85 min
Jun 11, 5:51 PM MDT	Severe Thunderstorm Watch	SPC	Adams, Billings, Bowman, Burke, Divide, Dunn and 13 more	7 hr

Nearby

Mesoscale Discussions in North Dakota, 2016 Mesoscale Discussions in South Dakota, 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.