Alert archive / Montana / Severe Thunderstorm Warnings in 1990

Severe Thunderstorm Warning 13, NWS Great Falls, MT

August 20, 1990Cascade County, Montana

NWS Great Falls, MT issued this severe thunderstorm warning at Aug 20, 1990, 4:30 PM MDT for Cascade County, Montana. It was in force for 60 min.

The area

The counties it named.

The facts

Issued
Aug 20, 1990, 4:30 PM MDT (22:30 UTC)
Expired
Aug 20, 1990, 5:30 PM MDT
In force
60 min
Issued by
NWS Great Falls, MT
Area
Whole counties

County Cascade County, MT

The radar

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

The nearest sounding before it

Great Falls, MT (KGTF), launched 12:00Z, 10.5 hours before the alert went out and 19 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 1990-08-20Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 3 joules per kilogram.LCLLFCEL10008507005003002001001 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 1990-08-20The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 83 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
3 J/kg
Mixed-layer CIN
-184 J/kg
Mixed-layer LCL
757 m above ground
0-6 km bulk shear
25 kt
0-1 km storm-relative helicity
83 m²/s²
0-3 km storm-relative helicity
96 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.

The office that day

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

IssuedProductOfficeCountiesLasted
Aug 19, 8:36 PM MDTFlash Flood WarningTFXFergus, Judith Basin2 hr
Aug 19, 8:36 PM MDTFlash Flood WarningTFXTeton2 hr
Aug 19, 8:36 PM MDTFlash Flood WarningTFXCascade69 min
Aug 20, 4:27 PM MDTSevere Thunderstorm WarningTFXCascade63 min
Aug 20, 5:13 PM MDTFlash Flood WarningTFXCascade, Chouteau, Judith Basin62 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; the sounding from the Mesonet's radiosonde archive.