Alert archive / Montana / Mesoscale Discussions in 2016

Mesoscale Discussion 981

June 18, 201617 counties in Montana

The Storm Prediction Center issued this mesoscale discussion at Jun 18, 2016, 5:56 PM MDT for 17 counties in Montana. It was in force for 2 hr.

The area

The outline as issued.

The facts

Issued: Jun 18, 2016, 5:56 PM MDT (23:56 UTC)
Expired: Jun 18, 2016, 8:00 PM MDT
In force: 2 hr
Issued by: the Storm Prediction Center

Counties Blaine County, MT, Cascade County, MT, Chouteau County, MT, Daniels County, MT, Fergus County, MT, Garfield County, MT, Hill County, MT, Judith Basin County, MT, Liberty County, MT, McCone County, MT, Petroleum County, MT, Phillips County, MT, Richland County, MT, Roosevelt County, MT, Sheridan County, MT, Toole County, MT, Valley County, MT

The radar

The Glasgow radar (KGGW), 160 km from the middle of the area, began a volume at 23:59 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

Glasgow Intl Airport, MT (KGGW), launched 12:00Z, 11.9 hours before the alert went out and 163 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: 1606 m above ground
0-6 km bulk shear: 60 kt
0-1 km storm-relative helicity: 111 m²/s²
0-3 km storm-relative helicity: 279 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

The text

As transmitted.

466 
ACUS11 KWNS 182357
SWOMCD
SPC MCD 182356 
MTZ000-190200-

MESOSCALE DISCUSSION 0981
NWS STORM PREDICTION CENTER NORMAN OK
0656 PM CDT SAT JUN 18 2016

AREAS AFFECTED...MT

CONCERNING...SEVERE THUNDERSTORM WATCH 271...

VALID 182356Z - 190200Z

THE SEVERE WEATHER THREAT FOR SEVERE THUNDERSTORM WATCH 271
CONTINUES.

SUMMARY...A THREAT FOR LARGE HAIL...WIND DAMAGE AND A TORNADO WILL
INCREASE OVER THE NEXT FEW HOURS ACROSS NRN MT.

DISCUSSION...LATEST SFC ANALYSIS SHOWS A 1007 MB LOW OVER SRN MT
WITH AN AREA OF BACKED WINDS NORTH AND EAST OF THE LOW ACROSS MUCH
OF NRN AND ERN MT. SCATTERED THUNDERSTORMS HAVE DEVELOPED OVER LAST
COUPLE OF HOURS IN THE HIGHER TERRAIN OF WRN MT AND THIS ACTIVITY IS
MOVING INTO AND ACROSS THE LOWER ELEVATIONS OF NRN MT. A SUPERCELL
IS LOCATED ALONG THE LEADING EDGE AND IS APPROACHING HAVRE MT EARLY
THIS EVENING. AHEAD OF THIS STORM...MODERATE INSTABILITY IS ANALYZED
BY THE RAP IN MOST OF NERN MT WHERE 0-6 KM SHEAR IS ESTIMATED IN THE
60 TO 70 KT RANGE AND 700-500 MB LAPSE RATES ARE APPROACHING 8.0
C/KM. THIS ENVIRONMENT WILL CONTINUE TO SUPPORT SUPERCELL
DEVELOPMENT WITH LARGE HAIL. HAILSTONES OF GREATER THAN 2 INCHES IN
DIAMETER WILL BE POSSIBLE WITH THE MORE DOMINANT SUPERCELLS.
LOW-LEVEL SHEAR IS ALSO FORECAST TO INCREASE OVER THE NEXT COUPLE OF
HOURS WHICH WILL MAKE A TORNADO POSSIBLE AS WELL. A SEVERE THREAT
MAY ALSO DEVELOP ACROSS SRN PARTS OF THE WATCH AS NEW CONVECTION
INITIATES AND STRENGTHENS OVER THE NEXT FEW HOURS.

..BROYLES/THOMPSON.. 06/18/2016

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

ATTN...WFO...BYZ...GGW...TFX...

LAT...LON   46900613 46870787 46730784 46760938 46670938 46710982
            46781009 46691034 46751055 47021110 46981147 46931151
            46911177 47111181 47161198 47261204 47561205 47561191
            47611192 47611165 47731165 47731143 48201136 48221164
            48321167 48471218 49021219 48990816 48990407 47370404
            47370408 47350447 47520451 47530455 47580456 47600496
            47700497 47680518 47800520 47790539 47180540 47180577
            47090582 47080592 47170609 47060609 46870607 46900613

SPC that day

Everything else SPC issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Jun 18, 2:43 PM MDT	Mesoscale Discussion	SPC	Blaine, Cascade, Chouteau, Daniels, Fergus, Garfield and 14 more	92 min
Jun 18, 3:16 PM MDT	Severe Thunderstorm Watch	SPC	Blaine, Cascade, Chouteau, Daniels, Dawson, Fergus and 14 more	8 hr

Nearby

Mesoscale Discussions in Montana, 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.