Alert archive / Montana / Severe Thunderstorm Warnings in 1990
Severe Thunderstorm Warning 8, NWS Missoula, MT
NWS Missoula, MT issued this severe thunderstorm warning at Aug 20, 1990, 11:20 PM MDT for Lewis and Clark County, Montana. It was in force for 25 min.
The area
The counties it named.
The facts
- Issued
- Aug 20, 1990, 11:20 PM MDT (05:20 UTC)
- Expired
- Aug 20, 1990, 11:45 PM MDT
- In force
- 25 min
- Issued by
- NWS Missoula, MT
- Area
- Whole counties
County Lewis and Clark 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 00:00Z, 5.3 hours before the alert went out and 91 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.
- Mixed-layer CAPE
- 236 J/kg
- Mixed-layer CIN
- -94 J/kg
- Mixed-layer LCL
- 1334 m above ground
- 0-6 km bulk shear
- 49 kt
- 0-1 km storm-relative helicity
- 176 m²/s²
- 0-3 km storm-relative helicity
- 214 m²/s²
- Significant tornado parameter
- 0.1
- Supercell composite
- 1.4
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, Aug 20, 7:43 PM MDT, 3 hours 37 minutes before
MTZ001-002-210330- SPECIAL WEATHER STATEMENT NATIONAL WEATHER SERVICE MISSOULA MT 730 PM MDT MON AUG 20 1990 ...STRONG THUNDERSTORMS MOVING THROUGH WESTERN MONTANA... AT 720 PM MDT...RADAR INDICATED SCATTERED THUNDERSTORMS WERE MOVING THROUGH WESTERN MONTANA. THE STRONGEST OF THESE THUNDERSTORMS HAVE MOVED INTO GRANITE AND RAVALLE COUNTIES DURING THE PAST HOUR...AND ARE MOVING TO THE NORTH AT ABOUT 25 MILES AN HOUR. THESE THUNDERSTORMS MAY CONTAIN STRONG GUSTY WINDS..BRIEF HEAVY RAIN.. FREQUENT LIGHTNING AND SMALL HAIL AND WILL CONTINUE THROUGH THIS EVENING. FURTHER STATEMENTS WILL BE ISSUED IF NECESSARY. END/RON
The office that day
Everything else NWS Missoula, MT issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Aug 20, 6:43 PM MDT | Severe Thunderstorm Warning | MSO | Lincoln | 62 min |
| Aug 20, 11:10 PM MDT | Severe Thunderstorm Warning | MSO | Lewis and Clark | 35 min |
| Aug 20, 11:52 PM MDT | Flash Flood Warning | MSO | Lewis and Clark | 2 hr |
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.