Alert archive / Montana / Severe Thunderstorm Warnings in 1998

Severe Thunderstorm Warning 11, NWS Missoula, MT

June 18, 1998Granite County, Montana

NWS Missoula, MT issued this severe thunderstorm warning at Jun 18, 1998, 8:40 PM MDT for Granite County, Montana. It was in force for 50 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
Jun 18, 1998, 8:40 PM MDT (02:40 UTC)
Expired
Jun 18, 1998, 9:30 PM MDT
In force
50 min
Issued by
NWS Missoula, MT
Area
Whole counties

County Granite County, MT

The radar

The Missoula radar (KMSX), 82 km from the middle of the area, began a volume at 02:39 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 nearest sounding before it

Great_falls, MT (KTFX), launched 00:00Z, 2.7 hours before the alert went out and 246 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, Great_falls, MT at 00:00Z on 1998-06-19Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 0 joules per kilogram.LCL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°0°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Great_falls, MT at 00:00Z on 1998-06-19The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 40 square meters per square second.193958Sfc1 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
0 J/kg
Mixed-layer CIN
No buoyant parcel
Mixed-layer LCL
2162 m above ground
0-6 km bulk shear
29 kt
0-1 km storm-relative helicity
40 m²/s²
0-3 km storm-relative helicity
69 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.

515 
WUUS1 KMSO 190244 RRA
SVRMSO
MTC039-190330-

BULLETIN - IMMEDIATE BROADCAST REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE MISSOULA MT
840 PM MDT THU JUN 18 1998

THE NATIONAL WEATHER SERVICE HAS ISSUED A

* SEVERE THUNDERSTORM WARNING FOR...
  EASTERN GRANITE COUNTY IN WEST CENTRAL MONTANA

* UNTIL 930 PM MDT

* AT 840 PM MDT...SEVERE THUNDERSTORM INDICATED 5 MILES SOUTHWEST
  OF DRUMMOND...BY NATIONAL WEATHER SERVICE DOPPLER RADAR...MOVING
  NORTHEAST AT 25 MPH.

* SEVERE THUNDERSTORM WILL BE NEAR...
  DRUMMOND AT 850 PM MDT


DESTRUCTIVE HAIL...DAMAGING WINDS...DEADLY LIGHTNING...AND VERY
HEAVY RAIN ARE ALL LIKELY WITH THIS STORM. FOR YOUR PROTECTION...
MOVE INSIDE A STRONG BUILDING...AND STAY AWAY FROM WINDOWS. DO NOT
DRIVE INTO AREAS WHERE WATER COVERS THE ROAD.

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 Jun 18, 8:30 PM MDT, 10 minutes earlier.

Area forecast discussion, Jun 18, 8:30 PM MDT, 10 minutes before
WESTERN MONTANA AND NORTH CENTRAL IDAHO FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MISSOULA MT
830 PM MDT THU JUN 18 1998

WHAT I CAN GLEAN FROM WOBBLY SATELLITE IMAGERY AND A FEW RAOBS LOOKS
LIKE IT FITS WITH CURRENT FORECASTS. SOME CONVECTION ACROSS WEST
CENTRAL MONTANA ASSOCIATED WITH DAYTIME HEATING AND INSTABILITY...AND
SHEAR WITH THIS ACTIVITY HAS LED TO A SEVERAL SPLITTING CELLS
PRODUCING A LOT OF PEA SIZED HAIL ACROSS SOUTHERN SECTIONS OF MONTANA
HALF OF CWA. CONVECTION GOING UP NOW IN IDAHO COUNTY LOOKS LIKE IT
IS FEELING THE INFLUENCES OF JET ROUNDING THE BOTTOM OF APPROACHING
LOW. WITH SHEAR ALREADY DECENT...THIS JET SHOULD CONTINUE TO ENHANCE
STORMS ACROSS IDAHO AND INTO SOUTHERN PARTS OF THE CWA...AND SPREAD
NORTHWARD THROUGH THE NIGHT AS FLOW BACKS. CURRENT FORECASTS LOOK
GOOD WITH HANDLING STORMS THROUGH THE OVERNIGHT PERIOD...AND WITHOUT
ANY NEW MODEL DATA...SEE NO REASON TO CHANGE ANYTHING IN LATER
PERIODS EITHER. NO UPDATE NEEDED. BARKER.

...FORECASTS BELOW ARE PRELIMINARY AND SUBJECT TO CHANGE...

LIB .. 049/067 047/070 ... 265764
FCA WW 048/064 046/068 048 265764
POL .. 048/064 047/069 ... 265764
MSO WW 049/063 046/068 047 265775
HMM .. 050/063 045/069 ... 265775
BTM .. 045/060 040/061 ... 265885
S80 .. 049/066 047/072 ... 265532
P69 .. 050/065 047/071 ... 265532
SMN .. 047/061 043/067 ... 264443

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; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.