Alert archive / Montana / Severe Thunderstorm Warnings in 1998
Severe Thunderstorm Warning 20, NWS Missoula, MT
NWS Missoula, MT issued this severe thunderstorm warning at Jul 3, 1998, 5:20 PM MDT for Granite County, Missoula County, Powell County, Montana. It was in force for 45 min. 2 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 3, 1998, 5:20 PM MDT (23:20 UTC)
- Expired
- Jul 3, 1998, 6:05 PM MDT
- In force
- 45 min
- Issued by
- NWS Missoula, MT
- Area
- Whole counties
Counties Granite County, MT, Missoula County, MT, Powell County, MT
What was reported inside it
| Time | Report | Where | Remark |
|---|---|---|---|
| Jul 3, 5:55 PM MDT | Hail 0.75 | Deer Lodge, MT | |
| Jul 3, 6:15 PM MDT | Thunderstorm Wind 56 | Clinton, 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 3, 1:00 PM MDT | Severe Thunderstorm Watch | SPC | 6 hr |
The nearest sounding before it
Great_falls, MT (KTFX), launched 12:00Z, 11.3 hours before the alert went out and 228 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
- 323 J/kg
- Mixed-layer CIN
- -38 J/kg
- Mixed-layer LCL
- 722 m above ground
- 0-6 km bulk shear
- 24 kt
- 0-1 km storm-relative helicity
- 6 m²/s²
- 0-3 km storm-relative helicity
- 108 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- -0.1
The text
As transmitted, in the capitals the NWS used until 2016.
471 WUUS1 KMSO 032326 RRA SVRMSO MTC039-063-077-040005- BULLETIN - IMMEDIATE BROADCAST REQUESTED SEVERE THUNDERSTORM WARNING NATIONAL WEATHER SERVICE MISSOULA MT 520 PM MDT FRI JUL 3 1998 THE NATIONAL WEATHER SERVICE HAS ISSUED A * SEVERE THUNDERSTORM WARNING FOR... EXTREME EASTERN MISSOULA COUNTY IN WEST CENTRAL MONTANA CENTRAL AND NORTHERN POWELL COUNTY IN WEST CENTRAL MONTANA NORTHERN GRANITE COUNTY IN WEST CENTRAL MONTANA * UNTIL 605 PM MDT * AT 518 PM MDT...NATIONAL WEATHER SERVICE RADAR INDICATED A LINE OF SEVERE THUNDERSTORMS FROM 10 MILES NORTHWEST OF SEELEY LAKE TO 5 MILES WEST OF DRUMMOND...MOVING NORTHEAST AT 20 MPH. * SEVERE THUNDERSTORM WILL BE NEAR... OVANDO AT 540 PM MDT DRUMMOND AT 530 PM MDT SEVERE THUNDERSTORMS PRODUCE DAMAGING WIND IN EXCESS OF 55 MPH... DESTRUCTIVE HAIL...DEADLY LIGHTNING...AND VERY HEAVY RAIN. FOR YOUR PROTECTION MOVE TO AN INTERIOR ROOM ON THE LOWEST FLOOR OF YOUR HOME OR BUSINESS. HEAVY RAINS FLOOD ROADS QUICKLY SO DO NOT DRIVE INTO AREAS WHERE WATER COVERS THE ROAD. GV
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 Missoula, MT wrote its last area forecast discussion before this severe thunderstorm warning went out at Jul 3, 2:45 PM MDT, 2 hours 35 minutes earlier.
Area forecast discussion, Jul 3, 2:45 PM MDT, 2 hours 35 minutes before
WESTERN MONTANA AND NORTH CENTRAL IDAHO FORECAST DISCUSSION NATIONAL WEATHER SERVICE MISSOULA MT 245 PM MDT FRI JUL 3 1998 MODELS IN FAIRLY GOOD AGREEMENT WITH LOCATION OF MAIN VORT MAX LOCATED NEAR THE WESTERN PORTION OF THE WASHINGTON-OREGON BORDER. ETA BETTER WITH THE FINER DETAILS SUCH A LOCATION OF VORT MAX OVER NORTHEASTERN WASHINGTON AND SOUTHERN OREGON. ACTIVITY WAS SLOW TO GET GOING OVER WESTERN MONTANA AS DRIER AIR ALOFT MOVED IN FROM THE GREAT BASIN THIS MORNING. CONVERGENCE ZONE OVER CENTRAL IDAHO FROM S80 TO MULLAN PASS ATTM AND MOVING SLOWLY NORTH. WITH STRONG LOW LEVEL CONVERGENCE ASSOCIATED WITH THERMAL TROF AND 850 LOW...LIS OF -4 TO -6 AND HIGH THETA-E VALUES A FEW SEVERE TSTMS HAD DEVELOPED OVER CENTRAL IDAHO. SPOTTERS AT ELK CITY REPORTED HEAVY RAIN AND PEA SIZE HAIL. SATELLITE SHOWING TSTM ACTIVITY SLOWLY MOVING EAST TOWARDS WEST CENTRAL MONTANA ATTM SO NEED TO WATCH THIS AREA CLOSELY. THE STORM PREDICTION CENTER HAS ISSUED A SEVERE TSTM WATCH FOR MOST OF IDAHO AND WESTERN MONTANA. TROF AXIS BECOMES MORE POSITIVE TILT AS IT SLOWLY MOVES EAST ON SATURDAY PUSHING THE THERMAL TROF EAST OF THE DIVIDE. TSTMS SHOULD DEVELOP AGAIN IN UNSTABLE AIR MASS ON SATURDAY...BUT EXPECT TO BE LESS INTENSE. TROF WEAKENS SUNDAY BUT AVN FORECASTS A STRONG SHORT WAVE TO MOVE INTO THE AREA SO LOOKS LIKE ANOTHER ROUND OF TSTM ACTIVITY. HARMER ...FORECASTS BELOW ARE PRELIMINARY AND SUBJECT TO CHANGE... LIB .. 060/078 056/076 ... 327535 FCA WE 058/078 054/075 052 327555 POL .. 060/072 056/068 ... 327545 MSO WE 057/079 054/075 053 327545 HMM .. 059/083 055/080 ... 327545 BTM .. 049/079 049/075 ... 324334 S80 .. 058/078 056/075 ... 328335 P69 .. 060/080 058/076 ... 328445 SMN .. 054/075 052/072 ... 325333
The office that day
Everything else NWS Missoula, MT issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Jul 2, 6:10 PM MDT | Severe Thunderstorm Warning | MSO | Ravalli | 45 min |
| Jul 3, 3:14 PM MDT | Severe Thunderstorm Warning | MSO | Mineral, Missoula | 46 min |
| Jul 3, 3:39 PM MDT | Severe Thunderstorm Warning | MSO | Mineral, Missoula | 61 min |
| Jul 3, 4:19 PM MDT | Severe Thunderstorm Warning | MSO | Lake, Missoula, Sanders | 61 min |
| Jul 3, 4:34 PM MDT | Flash Flood Warning | MSO | Lake, Missoula, Sanders | 86 min |
Nearby
Severe Thunderstorm Warnings in Montana, 1998Every severe thunderstorm warning in 1998
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.