Alert archive / Montana / Severe Thunderstorm Warnings in 2002

Severe Thunderstorm Warning 65, NWS Glasgow, MT

July 8, 2002Petroleum County, Montana

NWS Glasgow, MT issued this severe thunderstorm warning at Jul 8, 2002, 4:51 PM MDT for Petroleum County, Montana. It was in force for 54 min. 5 reports 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: Jul 8, 2002, 4:51 PM MDT (22:51 UTC)
Expired: Jul 8, 2002, 5:45 PM MDT
In force: 54 min
Issued by: NWS Glasgow, MT
Area: Counties, with a storm outline in the text

County Petroleum County, MT

The radar

The Billings radar (KBLX), 143 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.

What was reported inside it

Time	Report	Where	Remark
Jul 8, 5:10 PM MDT	Tornado F0	Winnett, MT	Two spotters saw a tornado 15 miles north of Winnett. It travelled through a rural area and caused no damage.
Jul 8, 5:21 PM MDT	Hail 1	Winnett, MT
Jul 8, 5:30 PM MDT	Thunderstorm Wind 63 M	Winnett, MT	Wind gust reported at the Dry Blood Creek RAWS site.
Jul 8, 5:30 PM MDT	Hail 1.25	Winnett, MT
Jul 8, 5:47 PM MDT	Hail 0.75	Winnett, 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 watch it was issued in

The SPC watch in force over the same counties when this warning went out.

Issued	Product	Office	Lasted
Jul 8, 1:00 PM MDT	Severe Thunderstorm Watch	SPC	6 hr
Jul 8, 4:45 PM MDT	Tornado Watch	SPC	5 hr

The nearest sounding before it

Glasgow Intl Airport, MT (KGGW), launched 12:00Z, 10.9 hours before the alert went out and 174 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: 214 J/kg
Mixed-layer CIN: -246 J/kg
Mixed-layer LCL: 1201 m above ground
0-6 km bulk shear: 26 kt
0-1 km storm-relative helicity: 119 m²/s²
0-3 km storm-relative helicity: 185 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.1

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 Jul 8, 2:40 PM MDT, 2 hours 11 minutes earlier.

Area forecast discussion, Jul 8, 2:40 PM MDT, 2 hours 11 minutes before

NORTHEAST MONTANA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GLASGOW MT
240 PM MDT MON JUL 8 2002

.SHORT TERM...SEVERE WATCH BOX INCLUDES WESTERN 4 COUNTIES.  EXPECT
THE COLD FRONT TO GENERATE ENOUGH DYNAMIC MIX TO GENERATE STRONG
THUNDERSTORMS.  FRONT IS MOVING RAPIDLY EAST AND WILL COMPLETELY
CROSS THE CWA BY LATE EVENING.  THETA E RIDGE AND CAPE GRADIENTS ARE
CONCENTRATED OVER THE CWA.  30+ KT LOW LEVEL JET CONTINUING STRONG
SOUTHEAST FLOW INTO THE CWA.  LAKE WIND ADVISORY WILL CONTINUE THIS
EVENING BECAUSE OF PROXIMITY TO CONVECTION OUTFLOW AND LOW LEVEL JET.

19Z SOUNDING SHOWING SOUTHEAST FLOW THROUGH 725MB BETWEEN 25-35
KTS.  ABOVE 725MB FLOW VEERS TO SOUTHWEST FOR REMAINDER OF
SOUNDING.  CAPE APPEARS LARGER THAN 12Z SOUNDING.  AIR COLUMN IS
WETTER THAN THE MORNING SOUNDING AND HINTS AT A LAPSE RATE NEARLY
PARALLEL TO THE MOIST ADIABATS FOR THIS AFTERNOON.  CWA IS STILL
AHEAD OF THE COLD FRONT AND LEADING INSTABILITY.  INDICES ARE: 2800+
J/KG CAPE  -8 LI  1.41 PW  314 SWEAT  63 M/S MAX VERT VELOCITY  82F
CONV TEMP

CIRRUS BLOW OFF FROM THUNDERSTORMS WEST OF CWA IS BEGINNING TO REACH
GGW.  CU FIELDS ARE DEVELOPING OVER THE AREA AND SHOWING SIGNS OF
INCREASED INSTABILITY.

.LONG TERM...MEDIUM RANGE MODELS IN FAIR AGREEMENT SO WILL CONTINUE
WITH THE AVN/MRF SOLUTION.  RIDGE WILL DOMINATE FRIDAY AND
SATURDAY.  A STRONG LOW WILL PUSH THROUGH THE RIDGE SUNDAY WITH A
TRAILING COLD POOL LASTING INTO MONDAY.  LOOKING AT POTENTIAL
THUNDERSTORMS SUNDAY AND MONDAY.  MCNULTY

KGGW BBB 057/082 056/085 052/078 81810011
     BBBW 059/087 059/091 058/090 055/087 8100000466
KGDV BBB 063/084 056/084 051/077 81710011
     BBBW 056/090 060/092 061/089 055/091 8100001337

.GGW...LAKE WIND ADVISORY FOR FORT PECK LAKE TONIGHT.

The office that day

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

Issued	Product	Office	Counties	Lasted
Jul 8, 5:01 PM MDT	Tornado Warning	GGW	Petroleum	59 min
Jul 8, 5:44 PM MDT	Tornado Warning	GGW	Garfield	61 min
Jul 8, 5:59 PM MDT	Severe Thunderstorm Warning	GGW	Petroleum	61 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; radar from the NEXRAD Level II archive.