Alert archive / Montana / Severe Thunderstorm Warnings in 2002

Severe Thunderstorm Warning 108, NWS Great Falls, MT

August 10, 2002Hill County, Montana

NWS Great Falls, MT issued this severe thunderstorm warning at Aug 10, 2002, 7:52 PM MDT for Hill 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: Aug 10, 2002, 7:52 PM MDT (01:52 UTC)
Expired: Aug 10, 2002, 8:30 PM MDT
In force: 38 min
Issued by: NWS Great Falls, MT
Area: Counties, with a storm outline in the text

County Hill County, MT

The radar

The Great Falls radar (KTFX), 181 km from the middle of the area, began a volume at 01:51 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
Aug 10, 8:15 PM MDT	Hail 1.25	Simpson, MT	A severe thunderstorm produced 1.25 inch hail at Simpson 6NE.

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, 1.9 hours before the alert went out and 164 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: 7 J/kg
Mixed-layer CIN: -25 J/kg
Mixed-layer LCL: 2931 m above ground
0-6 km bulk shear: 32 kt
0-1 km storm-relative helicity: 21 m²/s²
0-3 km storm-relative helicity: 130 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.1

Open this sounding in Storm Lab

The text

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

467 
WUUS55 KTFX 110152
SVRTFX
MTC041-110230-

BULLETIN - EAS ACTIVATION REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE GREAT FALLS MT
748 PM MDT SAT AUG 10 2002

THE NATIONAL WEATHER SERVICE IN GREAT FALLS HAS ISSUED A

* SEVERE THUNDERSTORM WARNING FOR...
  NORTH CENTRAL HILL COUNTY IN NORTH CENTRAL MONTANA

* UNTIL 830 PM MDT

* AT 745 PM MDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A
  SEVERE THUNDERSTORM OVER EXTREME NORTHWESTERN HILL COUNTY...OR     
  ABOUT 38 MILES NORTHEAST OF CHESTER...MOVING SOUTHEAST AT 30 MPH.

* THE SEVERE THUNDERSTORM WILL BE NEAR...
  SIMPSON AT 755 PM
  FRESNO RESERVOIR AT 805 PM.

THIS STORM MAY CONTAIN HAIL UP TO ONE AND A HALF INCHES IN 
DIAMETER...ALONG WITH WIND GUSTS TO 65 MPH.

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 4909 11035 4887 11061 4863 11019 4891 10994

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 Aug 10, 3:00 PM MDT, 4 hours 52 minutes earlier.

Area forecast discussion, Aug 10, 3:00 PM MDT, 4 hours 52 minutes before

SOUTHWEST AND NORTH CENTRAL MONTANA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREAT FALLS MT
300 PM MDT SAT AUG 10 2002

.SHORT TERM...A WEAK DISTURBANCE IS MOVING ACROSS NORTH AND CENTRAL
MT. THE BEST CHANCE FOR PRECIP FROM THIS DISTURBANCE WILL REMAIN
NORTH OF THE BORDER. THE ONLY AREA OF INSTABILITY IN THE CWA IS OVER
THE NORTHERN ZONES ALONG THE CANADIAN BORDER. CURRENT SATELLITE
INDICES STILL SHOW THE AREAS TO BE STABLE TO NEUTRAL BUT WILL KEEP
MENTION OF EVENING THUNDERSTORMS IN THE NORTHERN ZONES AS THEY SHOULD
BECOME SLIGHTLY MORE UNSTABLE. THE NEXT SYSTEM DUE ON SUNDAY IS
STRONGER. 3H JET COMES DOWN INTO CENTRAL MT BY 18Z SUN. LOTS OF
DIFLUENCE ALOFT OVER SRN SASK AND THAT AREA WILL HAVE MOST OF THE
ACTION. IN OUR CWA...THE VORT MAX MOVES DOWN THRU CENTRAL MT BUT
STAYS NORTH OF SW MT. THE INITIAL PUSH OF THE COLD FRONT WILL BRING
GUSTY NORTH WINDS AND A CHANCE OF PRECIP. HOWEVER...THE SURFACE HIGH
MOVES INTO THE AREA FROM THE NORTHWEST AND DOES NOT LOOK PARTICULARLY
STRONG OR COLD. THE SYSTEM SHOULD QUICKLY MOVE EAST AND NOT CREATE
ANY LINGERING EAST/UPSLOPE FLOW. ANOTHER WEAK SHORTWAVE MOVES THRU
THE AREA ON MONDAY AND SHOULD KEEP SKIES MOSTLY CLOUDY...BUT NO
PRECIP. DRY AND WARMER THRU TUESDAY. ZELZER

.EXTENDED...DRY NW FLOW ALOFT THROUGH PERIOD WITH A SHORT WAVE/COLD
FRONT TO MOVE THROUGH ON WEDNESDAY. WILL MENTION A SLIGHT CHANCE OF
SHOWERS FOR WEDNESDAY. TEMPERATURES SHOULD STAY COOLER THAN NORMAL.
FLOW BEGINS TO BECOME SW AND PICKING UP SOME MOISTURE BY NEXT
WEEKEND.  CAMP

.CCF NUMBERS
GTF EE 052/068 045/074 048 13121
    BEBBB 080/048 078/050 078/048 075/048 075 11112111111
CTB CE 049/065 043/070 046 13331
    BBBBB 076/048 076/045 078/048 074/048 074 11112111111
HLN EB 050/072 046/078 050 13121
    BBBBB 082/048 083/051 081/050 078/050 078 11112111111
BZN EB 044/074 040/076 040 13011
    BBBBB 078/046 080/047 078/045 079/047 076 11111111111
WEY EB 035/065 033/070 035 13011
    BBBBB 072/043 075/045 075/045 072/045 072 11111111111
DLN EB 047/074 042/073 042 13011
    BBBBB 075/048 080/050 080/047 078/047 078 11111111111
HVR WB 054/068 045/075 050 13331
    BBBBB 082/048 078/050 080/048 077/047 076 11112111111
LWT WB 047/067 042/070 045 13121
    BBBBB 075/046 077/048 078/050 075/047 073 11112111111

.TFX...NONE.

The office that day

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

Issued	Product	Office	Counties	Lasted
Aug 10, 8:32 PM MDT	Severe Thunderstorm Warning	TFX	Hill	28 min
Aug 10, 9:55 PM MDT	Severe Thunderstorm Warning	TFX	Blaine	20 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.