Alert archive / Montana / Severe Thunderstorm Warnings in 2002

Severe Thunderstorm Warning 131, NWS Great Falls, MT

September 4, 2002Pondera County, Teton County, Montana

NWS Great Falls, MT issued this severe thunderstorm warning at Sep 4, 2002, 10:45 PM MDT for Pondera County, Teton County, Montana. It was in force for 30 min. No storm report in the archive falls inside the area while it was in force.

The area

The counties it named.

The facts

Issued: Sep 4, 2002, 10:45 PM MDT (04:45 UTC)
Expired: Sep 4, 2002, 11:15 PM MDT
In force: 30 min
Issued by: NWS Great Falls, MT
Area: Counties, with a storm outline in the text

Counties Pondera County, MT, Teton County, MT

The radar

The Great Falls radar (KTFX), 90 km from the middle of the area, began a volume at 04:44 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.

Did it verify

Not verified. The Iowa Environmental Mesonet's Cow found no qualifying storm report inside this severe thunderstorm warning while it was in force. That is not proof nothing happened: reports are thin where few people live.

Cow counts a report within 15 km of the polygon while the warning was in force: a tornado for a tornado warning; hail of 1 inch or more, a gust of 58 mph or more or wind damage for a severe thunderstorm warning; a flash flood report for a flash flood warning.

The nearest sounding before it

Great_falls, MT (KTFX), launched 00:00Z, 4.8 hours before the alert went out and 138 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: 359 J/kg
Mixed-layer CIN: -127 J/kg
Mixed-layer LCL: 2121 m above ground
0-6 km bulk shear: 59 kt
0-1 km storm-relative helicity: -64 m²/s²
0-3 km storm-relative helicity: 47 m²/s²
Significant tornado parameter: 0.0
Supercell composite: -0.2

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 Great Falls, MT wrote its last area forecast discussion before this severe thunderstorm warning went out at Sep 4, 9:00 PM MDT, 1 hour 45 minutes earlier.

Area forecast discussion, Sep 4, 9:00 PM MDT, 1 hour 45 minutes before

SOUTHWEST AND NORTH CENTRAL MONTANA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREAT FALLS MT
900 PM MDT WED SEP 4 2002

.SHORT TERM...WILL UPDATE ZONES TO KEEP THUNDERSTORMS OVER NORTHWEST
AND EAST PART OF THE ZONES AS STORMS ARE POPPING UP ON RADAR...SOME
ARE PRETTY STRONG. WILL DROP MENTION OF STORMS OVER THE SOUTHWEST
ZONES. OTHERWISE REST OF FORECAST PACKAGE LOOKS GOOD.

.EXTENDED...PATTERN BECOMING MORE PROGRESSIVE DURING PERIOD. SUNDAY
STARTS OUT WITH A CONTINUED MOIST AND UNSTABLE SOUTHWEST FLOW
ALOFT...AS THE PACIFIC TROUGH MOVES INLAND. BY MONDAY...UPPER LOW
BECOMES CUTOFF ACROSS SOUTHERN MONTANA. OLD MRF SLOWER THAN THE
NEW AVN/ECMWF MODELS. WEAK RIDGE BUILDS INTO AREA BY MONDAY NIGHT
THROUGH WEDNESDAY FOR A RETURN TO DRIER WEATHER. MONDAY STILL LOOKS
LIKE A COOL RAINY DAY AS SURFACE HIGH PUSHES SOUTH FOR GOOD UPSLOPE
FLOW FOR THE NORTH CENTRAL MT. WILLIAMSON DC

.CCF NUMBERS
GTF EE 050/074 045/072 046 08344
    BEEBB 072/050 075/048 065/044 073/045 073 43303440000
CTB WE 047/069 046/066 043 08655
    BEEBB 068/046 072/044 060/039 068/040 068 42203440000
HLN EE 054/083 055/079 051 08134
    BEEBB 078/046 077/045 071/045 075/044 073 4050900-000
BZN EE 048/081 045/074 043 08234
    BEEBB 074/044 074/040 072/040 072/040 072 4050900-000
WEY EE 040/068 042/065 040 08244
    BEEBB 065/034 069/037 069/033 067/031 068 43324240000
DLN EE 050/075 047/072 045 08133
    BEEBB 072/039 071/042 070/039 072/037 070 4050900-000
HVR WE 053/077 050/072 046 08555
    BEEBB 073/046 077/049 066/048 074/047 074 42203340000
LWT EE 051/076 048/071 046 08345
    BEEBB 072/048 073/047 064/042 070/039 071 43303440000
.TFX...NONE

The office that day

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

Issued	Product	Office	Counties	Lasted
Sep 4, 9:39 PM MDT	Severe Thunderstorm Warning	TFX	Fergus	36 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; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.