Alert archive / Montana / Mesoscale Discussions in 2005

Mesoscale Discussion 1920

August 2, 20058 counties in Montana

The Storm Prediction Center issued this mesoscale discussion at Aug 2, 2005, 4:53 PM MDT for 8 counties in Montana. It was in force for 97 min.

The area

The outline as issued.

The facts

Issued
Aug 2, 2005, 4:53 PM MDT (22:53 UTC)
Expired
Aug 2, 2005, 6:30 PM MDT
In force
97 min
Issued by
the Storm Prediction Center

Counties Big Horn County, MT, Custer County, MT, Golden Valley County, MT, Musselshell County, MT, Powder River County, MT, Rosebud County, MT, Treasure County, MT, Yellowstone County, MT

The radar

The Billings radar (KBLX), 129 km from the middle of the area, began a volume at 22:54 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, 10.9 hours before the alert went out and 266 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-pSkew-T log-p diagram, Glasgow Intl Airport, MT at 12:00Z on 2005-08-02Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 589 joules per kilogram.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°0°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Glasgow Intl Airport, MT at 12:00Z on 2005-08-02The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity -88 square meters per square second.193958Sfc1 km3 km6 km9 kmRMLM
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
589 J/kg
Mixed-layer CIN
-307 J/kg
Mixed-layer LCL
1948 m above ground
0-6 km bulk shear
37 kt
0-1 km storm-relative helicity
-88 m²/s²
0-3 km storm-relative helicity
32 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.2

Open this sounding in Storm Lab

The text

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

000 
ACUS11 KWNS 022254
SWOMCD
SPC MCD 022253 
MTZ000-030030-

MESOSCALE DISCUSSION 1920
NWS STORM PREDICTION CENTER NORMAN OK
0553 PM CDT TUE AUG 02 2005

AREAS AFFECTED...S CENTRAL AND SE MT

CONCERNING...SEVERE THUNDERSTORM POTENTIAL 

VALID 022253Z - 030030Z

ISOLATED STRONG/DAMAGING WINDS POSSIBLE THE NEXT FEW HOURS ACROSS
CENTRAL/SE MT. SEVERE STORM COVERAGE SHOULD REMAIN RATHER ISOLATED
AND A WW IS NOT CURRENTLY ANTICIPATED...THOUGH THIS AREA WILL
CONTINUE TO BE MONITORED CLOSELY.

A LOOSELY ORGANIZED CLUSTER OF HIGH-BASED THUNDERSTORMS IS ONGOING
ACROSS S CENTRAL MT TO THE W OF BILLINGS.  WEAK ELY/NELY LOW-LEVEL
FLOW IMMEDIATELY DOWNSTREAM FROM THE CONVECTION WITH MODEST
STORM-RELATIVE INFLOW WILL ENHANCE STORM DEVELOPMENT ALONG THE
EXPANDING COLD POOL.  THOUGH INSTABILITY IS RELATIVELY WEAK /MUCAPE
VALUES AOB 500 J/KG/...STEEP LOW-LEVEL LAPSE RATES WILL SUPPORT
STRONG DOWNDRAFTS/OUTFLOW WINDS.

..THOMPSON.. 08/02/2005

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

ATTN...WFO...BYZ...

45290512 45070706 45100828 45530873 46110914 46480921
46700801 46650574 46300512 45720486

Nearby

Mesoscale Discussions in Montana, 2005Every mesoscale discussion in 2005

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.