Alert archive / Montana / Mesoscale Discussions in 2008

Mesoscale Discussion 2001

August 2, 200811 counties in Montana

The Storm Prediction Center issued this mesoscale discussion at Aug 2, 2008, 4:47 PM MDT for 11 counties in Montana. It was in force for 58 min.

The area

The outline as issued.

The facts

Issued: Aug 2, 2008, 4:47 PM MDT (22:47 UTC)
Expired: Aug 2, 2008, 5:45 PM MDT
In force: 58 min
Issued by: the Storm Prediction Center

Counties Beaverhead County, MT, Broadwater County, MT, Deer Lodge County, MT, Gallatin County, MT, Jefferson County, MT, Madison County, MT, Meagher County, MT, Park County, MT, Silver Bow County, MT, Sweet Grass County, MT, Wheatland County, MT

The radar

The Great Falls radar (KTFX), 160 km from the middle of the area, began a volume at 22:49 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 797Aug 2, 6:05 PM MDT

The nearest sounding before it

Great_falls, MT (KTFX), launched 12:00Z, 10.8 hours before the alert went out and 170 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: 2275 m above ground
0-6 km bulk shear: 49 kt
0-1 km storm-relative helicity: 59 m²/s²
0-3 km storm-relative helicity: 194 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

The text

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

000 
ACUS11 KWNS 022247
SWOMCD
SPC MCD 022247 
MTZ000-IDZ000-022345-

MESOSCALE DISCUSSION 2001
NWS STORM PREDICTION CENTER NORMAN OK
0547 PM CDT SAT AUG 02 2008

AREAS AFFECTED...PORTIONS OF MT

CONCERNING...SEVERE POTENTIAL...WATCH POSSIBLE 

VALID 022247Z - 022345Z

THUNDERSTORMS ARE CONTINUING TO DEVELOP OVER THE HIGHER TERRAIN IN
ID/MT THIS AFTERNOON. THE THREAT OF SEVERE STORM DEVELOPMENT WITH A
PRIMARY THREAT OF DMGG WINDS WILL INCREASE OVER THE NEXT FEW HOURS.
AREA IS BEING MONITORED FOR A POSSIBLE WW. 

A MID LEVEL SHORT WAVE OBSERVED ON WV IMAGERY IN ID HAS AIDED IN
THUNDERSTORM DEVELOPMENT OVER THE HIGHER TERRAIN OF ID/MT THIS
AFTERNOON. DESPITE LIMITED MOISTURE...STORMS ARE EXPECTED TO
CONTINUE TO INCREASE IN BOTH COVERAGE AND INTENSITY OVER MT AS
INSTABILITY INCREASES GIVEN MID LEVEL COOLING AHEAD OF THE WAVE AND
HEATING AT THE SURFACE. STRONG MID LEVEL FLOW WILL LIKELY REACH THE
SURFACE AS DEEPLY MIXED LOW LEVELS AND STEEP LAPSE RATES ENHANCE
DOWNBURST WINDS. BACKED LOW LEVEL FLOW AHEAD OF DEVELOPING
CONVECTION SHOULD HELP MAINTAIN LOW LEVEL CONVERGENCE AS COLD POOLS
PROGRESS INTO GREATER INSTABILITY.

..HURLBUT.. 08/02/2008

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

ATTN...WFO...BYZ...TFX...MSO...

45780959 45201105 44791260 45051376 45591403 46021362
46471277 46851182 47021061 46960976 46620929 46160916

SPC that day

Everything else SPC issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Aug 1, 9:54 PM MDT	Mesoscale Discussion	SPC	Wibaux	96 min

Nearby

Mesoscale Discussions in Montana, 2008 Every mesoscale discussion in 2008

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.