Alert archive / Montana / Severe Thunderstorm Warnings in 2002

Severe Thunderstorm Warning 41, NWS Great Falls, MT

July 6, 2002Cascade County, Montana

NWS Great Falls, MT issued this severe thunderstorm warning at Jul 6, 2002, 9:22 PM MDT for Cascade County, Montana. It was in force for 38 min. 1 report came from inside the area while it was in force.

The area

The outline as issued, with what was reported inside it.

The facts

Issued: Jul 6, 2002, 9:22 PM MDT (03:22 UTC)
Expired: Jul 6, 2002, 10:00 PM MDT
In force: 38 min
Issued by: NWS Great Falls, MT
Area: Counties, with a storm outline in the text

County Cascade County, MT

The radar

The Great Falls radar (KTFX), 39 km from the middle of the area, began a volume at 03:22 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 6, 9:30 PM MDT	Thunderstorm Wind 61 E	Eden, MT	A severe thunderstorm produced a wind gust of 70 mph near Eden.

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.

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, 3.4 hours before the alert went out and 57 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: 24 J/kg
Mixed-layer CIN: -338 J/kg
Mixed-layer LCL: 3087 m above ground
0-6 km bulk shear: 31 kt
0-1 km storm-relative helicity: 78 m²/s²
0-3 km storm-relative helicity: 134 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 
WUUS55 KTFX 070322
SVRTFX
MTC013-070400-

BULLETIN - EAS ACTIVATION REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE GREAT FALLS MT
924 PM MDT SAT JUL 6 2002

THE NATIONAL WEATHER SERVICE IN GREAT FALLS HAS ISSUED A

* SEVERE THUNDERSTORM WARNING FOR...
  CENTRAL CASCADE COUNTY IN CENTRAL MONTANA

* UNTIL 1000 PM MDT

* AT 920 PM MDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A
  SEVERE THUNDERSTORM 20 MILES WEST OF MONARCH...OR ABOUT 22 MILES
  EAST OF CASCADE...MOVING NORTH AT 25 MPH.

HAIL...INTENSE RAIN AND STRONG DAMAGING WINDS ARE LIKELY WITH THIS
STORM. TAKE COVER IN A SUBSTANTIAL SHELTER UNTIL THE STORM PASSES.

REPORT SEVERE WEATHER TO THE NEAREST LAW ENFORCEMENT AGENCY. THEY
WILL RELAY YOUR REPORT TO THE NATIONAL WEATHER SERVICE FORECAST
OFFICE IN GREAT FALLS.

LAT...LON 4702 11147 4710 11117 4699 11079 4740 11082
          4729 11142

.END
14

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 Jul 6, 8:35 PM MDT, 47 minutes earlier.

Area forecast discussion, Jul 6, 8:35 PM MDT, 47 minutes before

SOUTHWEST AND NORTH CENTRAL MONTANA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREAT FALLS MT
835 PM MDT SAT JUL 6 2002

WILL UPDATE ZONES BY 915 PM

.SHORT TERM...UPPER LEVEL DISTURBANCES IN A MOIST SOUTHWEST FLOW HAVE
KICKED OFF SCATTERED THUNDERSTORMS OVER MY SOUTHWEST ZONES THIS
EVENING. SEVERAL STORMS APPROACHED SEVERE CRITERIA...BUT PULSED DOWN
AGAIN...AND HAVE HAD NO REPORTS OF SEVERE WEATHER. DID RECEIVE
SEVERAL REPORTS OF HEAVY RAINS AND GUSTY WINDS IN LEWIS AND CLARK
COUNTY...BUT NO HAIL. RADAR AND SATELLITE OBSERVATIONS INDICATE THAT
ISOLATED CONVECTIVE ACTIVITY WILL CONTINUE IN THE SOUTHWEST THIS
EVENING...BUT THE MAIN STORM COMPLEX WILL MOVE THROUGH CENTRAL
MONTANA. WILL UPDATE TO FINE TUNE CHANCE OF PRECIPITATION...DROPPING
FAR SOUTHWEST ZONES DOWN TO ISOLATED AND INCREASING AREAS IN PATH
OF STORM COMPLEX TO LIKELY. TEMPERATURE FORECAST STILL LOOKS GOOD SO
NO CHANGES PLANNED FOR OVERNIGHT LOWS. MPJ

EXTENDED...MODELS CONTINUE TO BE IN VERY GOOD AGREEMENT BUILDING A
LARGE UPPER LEVEL HIGH OVER THE WESTERN CONUS. THE HIGH IS CENTERED
FAR ENOUGH SOUTH TO ALLOW AN UPPER LEVEL JET TO SET UP OVER SOUTHERN
CANADA ON THURSDAY. THE JET WILL ACT TO KEEP FLOW OVER THE NORTHERN
ROCKIES MORE OR LESS ZONAL THURSDAY THROUGH SATURDAY...KEEPING TEMPS
FROM SOARING AS MUCH AS PREVIOUSLY THOUGHT FOR THIS TIME PERIOD.
MODEL LIFTED INDICES INDICATE THAT A STABLE AIRMASS SHOULD REMAIN
OVER THE STATE FOR MUCH OF THE EXTENDED PERIOD...SO DRY AND WARM
FORECAST LOOKS ON TRACK. ONLY CHANGES TO GOING EXTENDED WILL BE TO
TWEAK HIGH TEMPS DOWN A DEGREE OR TWO IN ORDER TO BE MORE IN LINE
WITH GUIDANCE NUMBERS. MPJ

.CCF NUMBERS
GTF BT 056/089 058/093 050 01233
    BBBBB 085/052 092/055 090/054 088/053 086 63100000000
CTB BT 051/086 055/088 048 01123
    BBBBB 082/050 087/052 085/051 083/050 081 63100000000
HLN BT 058/090 058/092 053 01333
    BBBBB 085/052 092/056 090/055 089/054 087 63100000000
BZN BT 055/090 055/092 052 01333
    BBBBB 085/051 091/052 091/051 089/050 087 53100000000
WEY BT 045/080 045/085 043 01434
    BBBBB 078/044 082/043 081/042 080/041 079 52100000000
DLN BC 054/090 054/090 048 01333
    BBBBB 083/050 090/053 089/052 088/051 087 52100000000
HVR BT 058/090 062/095 052 01123
    BBBBB 085/054 092/056 091/055 090/054 088 63100000000
LWT BT 057/088 060/095 052 01334
    BBBBB 085/053 091/052 090/051 088/050 086 63110000000=

.TFX...NONE.

The office that day

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

Issued	Product	Office	Counties	Lasted
Jul 6, 8:46 PM MDT	Severe Thunderstorm Warning	TFX	Meagher	29 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.