Alert archive / Montana / Severe Thunderstorm Warnings in 1990

Severe Thunderstorm Warning 5, NWS Great Falls, MT

July 5, 1990Cascade County, Chouteau County, Montana

NWS Great Falls, MT issued this severe thunderstorm warning at Jul 5, 1990, 8:39 PM MDT for Cascade County, Chouteau County, Montana. It was in force for 66 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 5, 1990, 8:39 PM MDT (02:39 UTC)
Expired
Jul 5, 1990, 9:45 PM MDT
In force
66 min
Issued by
NWS Great Falls, MT
Area
Whole counties

Counties Cascade County, MT, Chouteau 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 5, 9:07 PM MDTThunderstorm Wind 59Cascade, MT
Jul 5, 9:10 PM MDTTornado F0Chouteau, 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

Glasgow Intl Airport, MT (KGGW), launched 00:00Z, 2.7 hours before the alert went out and 327 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, Glasgow Intl Airport, MT at 00:00Z on 1990-07-06Temperature 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, Glasgow Intl Airport, MT at 00:00Z on 1990-07-06The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity -19 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
0 J/kg
Mixed-layer CIN
No buoyant parcel
Mixed-layer LCL
2700 m above ground
0-6 km bulk shear
55 kt
0-1 km storm-relative helicity
-19 m²/s²
0-3 km storm-relative helicity
226 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.

In the hours before

Special weather statement, Jul 5, 7:50 PM MDT, 49 minutes before
MTC049-077-060345-

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE HELENA MT
749 PM MDT THU JUL 5 1990

...CONTINUED THUNDERSTORM DEVELOPMENT IN HELENA NATIONAL FOREST AREA.

AT 7:30 PM MDT, NATIONAL WEATHER SERVICE RADAR AND LIGHTNING DETECTION
EQUIPTMENT HAS SHOWN INCREASED THUNDERSTORM ACTIVITY IN THE HELENA
NATIONAL FOREST AREA, IN THE CENTRAL SECTIONS OF POWELL AND LEWIS &
CLARK COUNTIES. THE STORMS HAVE BEEN DEVELOPING ALONG A LINE BETWEEN
DRUMMOND AND GREAT FALLS AND ARE MOVING NORTHEAST.

PEOPLE OUTDOORS IN THESE AREAS SHOULD BE AWARE OF IMPENDING STORM
AND TAKE APPROPRIATE ACTION TO ENSURE PERSONAL SAFETY.
REMEMBER STRONG SUDDEN WINDS, DANGEROUS LIGHTNING, AND HEAVY RAIN,
AND HAIL AREA ALL POSSIBLE IN A THUNDERSTORM.

THUNDERSTORM ACTIVITY WILL CONTINUE THROUGH THIS EVENING.

END

The office that day

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

IssuedProductOfficeCountiesLasted
Jul 5, 9:23 PM MDTTornado WarningTFXCascade52 min
Jul 5, 9:54 PM MDTSevere Thunderstorm WarningTFXBlaine, Hill66 min
Jul 5, 10:19 PM MDTSevere Thunderstorm WarningTFXChouteau56 min
Jul 5, 10:56 PM MDTSevere Thunderstorm WarningTFXBlaine, Hill64 min
Jul 6, 12:02 AM MDTSevere Thunderstorm WarningTFXBlaine58 min
Jul 6, 12:52 AM MDTSevere Thunderstorm WarningTFXBlaine68 min

Nearby

Severe Thunderstorm Warnings in Montana, 1990Every severe thunderstorm warning in 1990

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.