Alert archive / Idaho / Severe Thunderstorm Warnings in 1997

Severe Thunderstorm Warning 4, NWS Missoula, MT

May 31, 1997Clearwater County, Idaho

NWS Missoula, MT issued this severe thunderstorm warning at May 31, 1997, 2:50 PM PDT for Clearwater County, Idaho. It was in force for 40 min. No storm report in the archive falls inside the area while it was in force.

The area

The counties it named.

The facts

Issued
May 31, 1997, 2:50 PM PDT (21:50 UTC)
Expired
May 31, 1997, 3:30 PM PDT
In force
40 min
Issued by
NWS Missoula, MT
Area
Whole counties

County Clearwater County, ID

The radar

The Missoula radar (KMSX), 133 km from the middle of the area, began a volume at 21:54 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.

The watch it was issued in

The SPC watch in force over the same counties when this warning went out.

IssuedProductOfficeLasted
May 31, 12:45 PM PDTTornado WatchSPC6 hr

The nearest sounding before it

Spokane, WA (KOTX), launched 12:00Z, 9.8 hours before the alert went out and 127 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-pSkew-T log-p diagram, Spokane, WA at 12:00Z on 1997-05-31Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 11 joules per kilogram.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Spokane, WA at 12:00Z on 1997-05-31The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 14 square meters per square second.19395878Sfc1 km3 km6 km9 kmRMLM
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

The text of this product is not in the archive. The NWS text archive before 2002 is incomplete.

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, 1:16 PM PDT, 1 hour 34 minutes earlier.

Area forecast discussion, May 31, 1:16 PM PDT, 1 hour 34 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.

IssuedProductOfficeCountiesLasted
May 31, 1:37 PM PDTSevere Thunderstorm WarningMSOClearwater53 min

Nearby

Severe Thunderstorm Warnings in Idaho, 1997Every 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; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.