Alert archive / Montana / Severe Thunderstorm Warnings in 1986

Severe Thunderstorm Warning 21, NWS Billings, MT

July 15, 1986Golden Valley County, Stillwater County, Sweet Grass County, Montana

NWS Billings, MT issued this severe thunderstorm warning at Jul 15, 1986, 5:04 PM MDT for Golden Valley County, Stillwater County, Sweet Grass County, Montana. It was in force for 56 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
Jul 15, 1986, 5:04 PM MDT (23:04 UTC)
Expired
Jul 15, 1986, 6:00 PM MDT
In force
56 min
Issued by
NWS Billings, MT
Area
Whole counties

Counties Golden Valley County, MT, Stillwater County, MT, Sweet Grass County, MT

The radar

The WSR-88D network and its archive begin in 1991, so there is no radar volume for this alert.

What was reported inside it

TimeReportWhereRemark
Jul 15, 5:35 PM MDTThunderstorm Wind 56Stillwater, 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. Storm Data before 1996 records only tornadoes, thunderstorm wind and hail.

The nearest sounding before it

Great_falls, MT (KTFX), launched 12:00Z, 11.1 hours before the alert went out and 187 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 12:00Z on 1986-07-15Temperature 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 12:00Z on 1986-07-15The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity -9 square meters per square second.1939587897117Sfc1 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
3577 m above ground
0-6 km bulk shear
66 kt
0-1 km storm-relative helicity
-9 m²/s²
0-3 km storm-relative helicity
117 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 KBIL 152305
SVRBIL
MTC037-095-097-160000-

BULLETIN - IMMEDIATE BROADCAST REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE BILLINGS MT
504 PM MDT TUE JUL 15 1986

THE NATIONAL WEATHER SERVICE HAS ISSUED A SEVERE THUNDERSTORM
WARNING EFFECTIVE UNTIL 600 PM MDT FOR PEOPLE IN THE FOLLOWING
COUNTIES OF

MONTANA...SOUTHERN GOLDEN VALLEY...NORTHERN STILLWATER AND EASTERN
SWEET GRASS.

AT 5 PM MDT RADAR INDICATED A SEVERE THUNDERSTORM 15 MILES
EAST OF BIG TIMBER...IN SWEETGRASS COUNTY. THIS THUNDERSTORM
WAS MOVING EAST AT 35 MPH.

HAIL AND VERY HEAVY RAIN HAVE BEEN REPORTED WITH THIS STORM.

IF THREATENING WEATHER APPROACHES...TAKE COVER IMMEDIATELY.

IF THREATENING WEATHER APPROACHES GO TO A SAFE PLACE IMMEDIATELY.
WHEN IT IS SAFE PLEASE ASK THE NEAREST LAW ENFORCEMENT AGENCY
TO RELAY YOUR SEVERE WEATHER REPORTS TO THE NEAREST NATIONAL
WEATHER SERVICE OFFICE, OR CALL THE NATIONAL WEATHER SERVICE  AT
BILLINGS MONTANA. 406-657-6988
END/DRN

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.

In the hours before

Local storm report, Jul 15, 4:49 PM MDT, 15 minutes before
^GTFLSRBIL
STORM REPORT
NATIONAL WEATHER SERVICE BILLINGS MT
 445 PM MDT TUE JUL 15 1986

 TIME OF OCCURRENCE       EVENT

437 PM MDT                HAIL SLIGHTLY LARGER THAN MARBLE SIZE...VERY
                          HEAVY RAIN AT BIG TIMBER MONTANA...SWEETGRASS
                          COUNTY. HAIL COMPLETELY COVERED THE GROUND...
                          HAILED FOR ABOUT 10 MINUTES. REPORTED BY THE
                          SHERIFFS OFFICE IN BIG TIMBER.
END/NOLL

The office that day

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

IssuedProductOfficeCountiesLasted
Jul 15, 4:14 PM MDTSevere Thunderstorm WarningBYZSweet Grass46 min

Nearby

Severe Thunderstorm Warnings in Montana, 1986Every severe thunderstorm warning in 1986

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.