Alert archive / Montana / Tornado Warnings in 1999
Tornado Warning 2, NWS Great Falls, MT
NWS Great Falls, MT issued this tornado warning at Aug 7, 1999, 6:54 PM MDT for Teton County, Montana. It was in force for 31 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 7, 1999, 6:54 PM MDT (00:54 UTC)
- Expired
- Aug 7, 1999, 7:25 PM MDT
- In force
- 31 min
- Issued by
- NWS Great Falls, MT
- Area
- Whole counties
County Teton County, MT
The radar
The Great Falls radar (KTFX), 77 km from the middle of the area, began a volume at 00:56 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 7, 6:56 PM MDT | Hail 1.75 | Choteau, 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 |
|---|---|---|---|
| Aug 7, 3:15 PM MDT | Severe Thunderstorm Watch | SPC | 6 hr |
The nearest sounding before it
Great_falls, MT (KTFX), launched 00:00Z, 0.9 hours before the alert went out and 130 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.
- Mixed-layer CAPE
- 671 J/kg
- Mixed-layer CIN
- -36 J/kg
- Mixed-layer LCL
- 2636 m above ground
- 0-6 km bulk shear
- 51 kt
- 0-1 km storm-relative helicity
- 74 m²/s²
- 0-3 km storm-relative helicity
- 130 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 4.0
The text
As transmitted, in the capitals the NWS used until 2016.
000 TTAA00 KGTF 080058 RRA TORGTF MTC099-080125- BULLETIN - EAS ACTIVATION REQUESTED TORNADO WARNING NATIONAL WEATHER SERVICE GREAT FALLS MT 654 PM MDT SAT AUG 7 1999 THE NATIONAL WEATHER SERVICE IN GREAT FALLS HAS ISSUED A * TORNADO WARNING FOR... CENTRAL TETON COUNTY IN NORTHWESTERN MONTANA * UNTIL 725 PM MDT * AT 653 PM MDT... DOPPLER RADAR AT GREAT FALLS INDICATED A TORNADO IN THE VICINITY OF CHOTEAU... MOVING NORTHEAST AT 25 MPH. THE TORNADO IS EXPECTED TO MOVE OVER CHOUTEAU BY 715 PM MDT. GO TO THE BASEMENT OR A SMALL INTERIOR ROOM ON THE LOWEST FLOOR! PE
What forecasters said that day
The local office's own words before this tornado 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 tornado warning went out at Aug 7, 3:00 PM MDT, 3 hours 54 minutes earlier.
Area forecast discussion, Aug 7, 3:00 PM MDT, 3 hours 54 minutes before
SOUTHWEST AND NORTH CENTRAL MONTANA FORECAST DISCUSSION NATIONAL WEATHER SERVICE GREAT FALLS MT 300 PM MDT SAT AUG 7 1999 UPPER LOW TO TAKE THE HILINE ACROSS MT TONIGHT AND SUNDAY WITH VORTICITY SHEARING SUNDAY. HOWEVER...WITH ITS APPROACH TODAY THERMODYNAMIC SETUP IMPRESSIVE ACROSS CWA. CAPES BETWEEN 1K AND 2K WITH LIS FORECAST BETWEEN -2 AND -4 WILL COMBINE WITH INCREASINGLY FAVORABLE SHEAR PROFILES...JET DYNAMICS...LOW LEVEL CONVERGENCE AND OMEGA VALUES TO SET THE STAGE FOR THUNDERSTORMS TO RAPIDLY BECOME SEVERE LATE THIS AFTERNOON THROUGH THIS EVENING. DYNAMICS AND THERMODYNAMICS TO PUSH EAST OUT OF CWA BY 08/18Z LEAVING DRY AND SLIGHTLY COOLER WEATHER FOR SUNDAY AND MONDAY. SLGT RISK BY SPC AND THEY ARE ALREADY MENTIONING A POSSIBLE SVR BOX FOR WRN MT. ISSUED SPS TO HIGHLIGHT SVR THREAT FOR CWA AND WILL MAINTAIN MENTION OF SVR IN AFTERNOON ZONE PACKAGE FOR 1ST PERIOD (TONIGHT). DITTMANN GTF 5100 HLN 5100 HVR 5200
The office that day
Everything else NWS Great Falls, MT issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Aug 7, 6:10 PM MDT | Severe Thunderstorm Warning | TFX | Teton | 60 min |
| Aug 7, 6:28 PM MDT | Severe Thunderstorm Warning | TFX | Pondera | 42 min |
| Aug 7, 7:16 PM MDT | Severe Thunderstorm Warning | TFX | Teton | 44 min |
| Aug 7, 7:31 PM MDT | Severe Thunderstorm Warning | TFX | Pondera | 59 min |
| Aug 7, 8:13 PM MDT | Severe Thunderstorm Warning | TFX | Toole | 57 min |
| Aug 7, 9:00 PM MDT | Severe Thunderstorm Warning | TFX | Liberty, Toole | 60 min |
| Aug 7, 9:15 PM MDT | Severe Thunderstorm Warning | TFX | Chouteau, Hill | 45 min |
| Aug 7, 10:00 PM MDT | Severe Thunderstorm Warning | TFX | Hill, Liberty, Toole | 35 min |
| Aug 8, 12:04 AM MDT | Severe Thunderstorm Warning | TFX | Pondera, Toole | 26 min |
| Aug 8, 12:30 AM MDT | Severe Thunderstorm Warning | TFX | Liberty, Toole | 30 min |
Nearby
Tornado Warnings in Montana, 1999Every tornado warning in 1999Tornadoes in 1999
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.