Alert archive / Montana / Severe Thunderstorm Warnings in 1997

Severe Thunderstorm Warning 7, NWS Missoula, MT

May 31, 1997Lincoln County, Sanders County, Montana

NWS Missoula, MT issued this severe thunderstorm warning at May 31, 1997, 4:34 PM MDT for Lincoln County, Sanders County, Montana. It was in force for 41 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: May 31, 1997, 4:34 PM MDT (22:34 UTC)
Expired: May 31, 1997, 5:15 PM MDT
In force: 41 min
Issued by: NWS Missoula, MT
Area: Whole counties

Counties Lincoln County, MT, Sanders County, MT

The radar

The Missoula radar (KMSX), 153 km from the middle of the area, began a volume at 22:35 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
May 31, 4:40 PM MDT	Thunderstorm Wind 52	Troy, MT
May 31, 5:00 PM MDT	Thunderstorm Wind 57	Noxon, MT	Thunderstorm wind gusts up to 65 mph measured at Noxon school weather station. Numerous trees and power lines knocked down with power outages.

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
May 31, 4:15 PM MDT	Severe Thunderstorm Watch	SPC	6 hr

The nearest sounding before it

Spokane, WA (KOTX), launched 12:00Z, 10.6 hours before the alert went out and 96 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: 11 J/kg
Mixed-layer CIN: -225 J/kg
Mixed-layer LCL: 1213 m above ground
0-6 km bulk shear: 50 kt
0-1 km storm-relative helicity: 14 m²/s²
0-3 km storm-relative helicity: 146 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 
TTAA00 KMSO 312239 RRA
SVRMSO
MTC053-089-312315-
 
BULLETIN - IMMEDIATE BROADCAST REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE MISSOULA MT
434 PM MDT SAT MAY 31 1997
 
THE NATIONAL WEATHER SERVICE IN MISSOULA HAS ISSUED A
SEVERE THUNDERSTORM WARNING EFFECTIVE UNTIL  515 PM MDT
FOR PEOPLE IN THE FOLLOWING LOCATIONS...
 
IN NORTHWEST MONTANA
 
   ...LINCOLN COUNTY
 
IN WEST CENTRAL MONTANA
 
   ...SANDERS COUNTY
 
AT 435 PM MDT RADAR INDICATED A LINE OF SEVERE THUNDERSTORMS RUNNING
FROM TROY TO NOXON MOVING TO THE EAST 30 MPH. THE STRONGEST STORM WAS 5
MILES EAST OF NOXON.
 
LARGE HAIL...WIND GUSTS TO NEAR 60 MPH...AND BRIEF HEAVY RAIN CAN BE
EXPECTED WITH THESE STORMS.
 
WHEN THUNDERSTORMS ARE OCCURRING...PEOPLE SHOULD MOVE INSIDE A
STRONG BUILDING.  DO NOT STAND BY WINDOWS.  DON'T USE TELEPHONES
OR ELECTRICAL APPLIANCES UNLESS IN AN EMERGENCY UNTIL THE STORM
HAS PASSED.  MOTORISTS SHOULD NOT DRIVE INTO LOW WATER CROSSINGS.
 
WHITMORE/FOSS

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 May 31, 2:16 PM MDT, 2 hours 18 minutes earlier.

Area forecast discussion, May 31, 2:16 PM MDT, 2 hours 18 minutes before

WESTERN MONTANA AND NORTH CENTRAL IDAHO FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MISSOULA MT
145 PM MDT SAT MAY 31 1997

HYDRO
...FLOOD WARNINGS...BITTERROOT RIVER IN RAVALLI COUNTY..ROCK CREEK
IN GRANITE AND MISSOULA COUNTY.
...FLOOD WATCH...YAAK RIVER IN LINCOLN COUNTY..SOUTH FORK OF THE
FLATHEAD RIVER ABOVE THE HUNGRY HORSE DAM..AND CLARK FORK RIVER FROM
MILLTOWN DAM THROUGH MISSOULA.

MET.
S/WV AND SURFACE FRONT MOVES ACROSS THE AREA THIS EVENING WITH
SHOWERS AND THUNDERSTORMS...A FEW POSSIBLY SEVERE. A TORNADO WATCH
IS IN EFFECT FOR IDAHO ZONES 5-8. WILL GO WITH LIKELY POPS MOST AREAS
TONIGHT. MODELS INDICATING ATMS MORE STABLE AND DRIER
SUNDAY..HOWEVER WITH WEAK S/WVS MOVING THRU THE SOUTHWEST FLOW WILL
NOT RULE OUT SCATTERED SHOWERS SUNDAY AFTERNOON. WEAK S/WV MOVES
ACROSS LEMHI COUNTY IDAHO AND SOUTHWEST MONTANA MONDAY MORNING
HOWEVER A SLIGHT CHANCE LOOKS GOOD FOR THIS EVENT. COOLER NEXT COUPLE
OF DAYS.
TC
...FORECASTS BELOW ARE PRELIMINARY AND SUBJECT TO CHANGE...

LIB .. 048/065 045/067 ... 296310
FCA EB 046/064 043/066 043 296310
POL .. 047/065 044/068 ... 296310
MSO EB 047/067 044/069 046 296311
HMM .. 048/070 046/071 ... 296312
BTM .. 044/064 040/066 ... 296212
S80 .. 052/067 048/069 ... 296311
P69 .. 051/069 050/072 ... 297410
SMN .. 047/073 045/075 ... 294100

The office that day

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

Issued	Product	Office	Counties	Lasted
May 31, 4:25 PM MDT	Severe Thunderstorm Warning	MSO	Beaverhead	45 min
May 31, 4:30 PM MDT	Severe Thunderstorm Warning	MSO	Beaverhead	45 min
May 31, 4:49 PM MDT	Severe Thunderstorm Warning	MSO	Mineral	41 min
May 31, 5:55 PM MDT	Severe Thunderstorm Warning	MSO	Lake, Missoula	65 min

Nearby

Severe Thunderstorm Warnings in Montana, 1997 Every severe thunderstorm warning in 1997

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.