Alert archive / Montana / Mesoscale Discussions in 2014

Mesoscale Discussion 752

May 28, 201416 counties in Montana; Divide County, North Dakota

The Storm Prediction Center issued this mesoscale discussion at May 28, 2014, 8:21 PM MDT for 16 counties in Montana; Divide County, North Dakota. It was in force for 114 min.

The area

The outline as issued.

The facts

Issued: May 28, 2014, 8:21 PM MDT (02:21 UTC)
Expired: May 28, 2014, 10:15 PM MDT
In force: 114 min
Issued by: the Storm Prediction Center

Counties Blaine County, MT, Custer County, MT, Daniels County, MT, Dawson County, MT, Fallon County, MT, Garfield County, MT, McCone County, MT, Musselshell County, MT, Petroleum County, MT, Phillips County, MT, Prairie County, MT, Richland County, MT, Roosevelt County, MT, Sheridan County, MT, Valley County, MT, Wibaux County, MT, Divide County, ND

The radar

The Glasgow radar (KGGW), 109 km from the middle of the area, began a volume at 02:23 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 00:00Z, 2.4 hours before the alert went out and 111 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: 2700 J/kg
Mixed-layer CIN: -27 J/kg
Mixed-layer LCL: 1848 m above ground
0-6 km bulk shear: 42 kt
0-1 km storm-relative helicity: 46 m²/s²
0-3 km storm-relative helicity: 251 m²/s²
Significant tornado parameter: 0.5
Supercell composite: 16.2

Open this sounding in Storm Lab

The text

As transmitted, in the capitals the NWS used until 2016.

233 
ACUS11 KWNS 290221
SWOMCD
SPC MCD 290221 
NDZ000-MTZ000-290415-

MESOSCALE DISCUSSION 0752
NWS STORM PREDICTION CENTER NORMAN OK
0921 PM CDT WED MAY 28 2014

AREAS AFFECTED...ROUGHLY THE NERN QUARTER OF MT

CONCERNING...SEVERE THUNDERSTORM WATCH 196...197...

VALID 290221Z - 290415Z

THE SEVERE WEATHER THREAT FOR SEVERE THUNDERSTORM WATCH
196...197...CONTINUES.

SUMMARY...ISOLATED SEVERE RISK CONTINUES ACROSS THE NERN MT
VICINITY...PARTICULARLY OVER THE TIER OF COUNTIES ADJACENT TO THE
U.S./CANADIAN BORDER.

DISCUSSION...LATEST RADAR LOOP CONTINUES TO SHOW TWO MAIN CLUSTERS
OF CONVECTION ATTM -- ONE OVER BLAINE CO MT AND THE OTHER MOVING
ACROSS THE MCCONE/PRAIRIE/DAWSON CO MT AREA.  WHILE ISOLATED SEVERE
WEATHER REMAINS POSSIBLE WITH THIS ERN MT STORM CLUSTER...GREATER
SEVERE RISK PERSISTS WITH THE MORE ORGANIZED N CENTRAL MT STORMS. 
STORMS WITHIN THIS CLUSTER REMAIN MUCH MORE ORGANIZED/INTENSE --
EXHIBITING BOTH BOWING AND SUPERCELL STRUCTURES.  WHILE SEVERE RISK
WILL EVENTUALLY DIMINISH AS THE BOUNDARY LAYER STABILIZES AND AS
MORE INTENSE STORMS EVENTUALLY SHIFT INTO SRN SASKATCHEWAN...
POTENTIAL FOR STRONG/DAMAGING GUSTS REMAINS LIKELY ACROSS NERN MT AS
STORMS MOVE QUICKLY ENEWD OVER THE NEXT 1-2 HOURS.

..GOSS.. 05/29/2014

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

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

LAT...LON   46430413 45720481 46520673 46230873 46630914 47790911
            48560945 49050896 49040342 46430413

SPC that day

Everything else SPC issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
May 28, 6:28 PM MDT	Mesoscale Discussion	SPC	Big Horn, Blaine, Carbon, Chouteau, Custer, Daniels and 24 more	92 min
May 29, 2:15 PM MDT	Mesoscale Discussion	SPC	Adams, Billings, Bottineau, Bowman, Burke, Dunn and 14 more	60 min
May 29, 2:45 PM MDT	Severe Thunderstorm Watch	SPC	Adams, Billings, Bottineau, Bowman, Burke, Burleigh and 15 more	6 hr
May 29, 5:25 PM MDT	Mesoscale Discussion	SPC	Adams, Billings, Bottineau, Bowman, Burke, Dunn and 12 more	65 min

Nearby

Mesoscale Discussions in Montana, 2014 Mesoscale Discussions in North Dakota, 2014 Every mesoscale discussion in 2014

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.