Alert archive / Montana / Severe Thunderstorm Warnings in 2002

Severe Thunderstorm Warning 138, NWS Glasgow, MT

August 30, 2002Valley County, Montana

NWS Glasgow, MT issued this severe thunderstorm warning at Aug 30, 2002, 1:08 AM MDT for Valley County, Montana. It was in force for 52 min. 1 report came from inside the area while it was in force.

The area

The counties it named, with what was reported inside it.

The facts

Issued: Aug 30, 2002, 1:08 AM MDT (07:08 UTC)
Expired: Aug 30, 2002, 2:00 AM MDT
In force: 52 min
Issued by: NWS Glasgow, MT
Area: Counties, with a storm outline in the text

County Valley County, MT

What was reported inside it

Time	Report	Where	Remark
Aug 30, 1:30 AM MDT	Hail 0.88	Opheim, MT

NCEI Storm Data entries that began inside the alert's area while it was in force. Before 2003 the local storm report archive is thin, so this is the record of what happened rather than what was phoned in.

The nearest sounding before it

Glasgow Intl Airport, MT (KGGW), launched 00:00Z, 7.1 hours before the alert went out and 17 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: 639 J/kg
Mixed-layer CIN: -98 J/kg
Mixed-layer LCL: 2487 m above ground
0-6 km bulk shear: 26 kt
0-1 km storm-relative helicity: -19 m²/s²
0-3 km storm-relative helicity: 49 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.8

Open this sounding in Storm Lab

What forecasters said that day

The local office's own words before this severe thunderstorm warning went out, as it sent them, from the Iowa Environmental Mesonet's archive of National Weather Service text.

NWS Glasgow, MT wrote its last area forecast discussion before this severe thunderstorm warning went out at Aug 29, 8:25 PM MDT, 4 hours 43 minutes earlier.

Area forecast discussion, Aug 29, 8:25 PM MDT, 4 hours 43 minutes before

NORTHEAST MONTANA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GLASGOW MT
825 PM MDT THU AUG 29 2002

.SHORT TERM...CURRENT RADAR IMAGERY FROM ALL THREE MT OFFICES EAST
OF THE DIVIDE SHOWING ON-GOING CONVECTION ACROSS MUCH OF THE STATE.
THE MAIN CLUSTERS ARE OVER AN AREA BETWEEN JORDAN AND BILLINGS WITH
MORE SCATTERED AREAS OF SHOWERS AND STORMS TO THE EAST AND NORTHWEST
OF GREAT FALLS. STORM MOTION IS TO THE NORTH/NORTHEAST AND IT
APPEARS MOST IF NOT ALL OF THIS ACTIVITY TO OUR WEST SHOULD STAY
THERE BEFORE DISSIPATING. THE AREA OF SHOWERS AND STORMS CURRENTLY
AFFECTING SOUTHERN GARFIELD COUNTY SHOULD CONTINUE TO SPREAD FURTHER
NORTH INTO THE THE SOUTHERN AND WESTERN PORTIONS OF THE CWA THIS
EVENING. 00Z KGGW SOUNDING SHOWS DRY LOWER TO MID LEVELS...AIDING IN
STRONG OUTFLOW FROM THUNDERSTORMS. SEVERE ACTIVITY HAS STAYED TO THE
WEST AND SOUTH...AND BELIEVE WITH THE SETTING OF THE SUN AND CLOUD
COVER THE INSTABILITY WILL CONTINUE TO WEAKEN AS THE NIGHT WEARS ON.
ALL THIS ACTIVITY IS ASSOCIATED WITH A COUPLE OF UPPER LEVEL
SHORTWAVES MOVING OVER THE STATE ALONG WITH A WEAK SURFACE FRONT.
WILL UPDATE WORDING ON WINDS IN THE NORTHERN GROUPINGS SINCE THEY
HAVE DIMINISHED AND HAVE STARTED TO BACK TO AN EASTERLY
DIRECTION...AND WILL DELAY THE ONSET OF PRECIP IN THE NORTHEAST
ZONES...OTHERWISE FORECAST LOOKS ON TRACK.  BERDES

.LONG TERM... PATTERN FOR NEXT WEEK NOW LOOKING A BIT MORE AMPLIFIED
THAN PREVIOUS.  AFTER SUNDAY NIGHT/EARLY MONDAY TROF WE GET RIDGING
INTO OR THRU THURSDAY.  ANOTHER TROF THEN COMES OUR WAY EITHER
WEDNESDAY NIGHT OR THURSDAY.  APPEARS THAT MONDAY TO BE THE COLDEST
DAY AFTER THE TROF DROPS HEIGHTS AND THICKNESSES AND THE COLDEST LOW
LEVEL AIR (0 TO -2 C AT 700MB) FOLLOWING SATURDAYS FRONT FINALLY
TRUNDLES IN.  BUT ALL IN ALL...NEXT WEEK NOT LOOKING NEARLY AS WET
AS THE LAST FEW WEEKS.  VALONE

KGGW BBB 060/083 057/076 050/079 78433221
     BUUU 051/069 044/076 052/080 050/077 7821010222
KGDV BBB 062/086 057/083 053/081 78433221
     BUUU 051/070 045/079 052/082 050/079 7811010222

.GGW...NONE

The office that day

Everything else NWS Glasgow, MT issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Aug 30, 2:25 AM MDT	Severe Thunderstorm Warning	GGW	Valley	65 min

Nearby

Severe Thunderstorm Warnings in Montana, 2002 Every severe thunderstorm warning in 2002

Sources

The product and its follow-ups from the Iowa Environmental Mesonet's archive of National Weather Service and Storm Prediction Center text; verification from NCEI's Storm Data; the sounding from the Mesonet's radiosonde archive.