Alert archive / Montana / Severe Thunderstorm Warnings in 1989

Severe Thunderstorm Warning 13, NWS Great Falls, MT

July 30, 1989Fergus County, Montana

NWS Great Falls, MT issued this severe thunderstorm warning at Jul 30, 1989, 7:35 PM MDT for Fergus County, Montana. It was in force for 55 min.

The area

The counties it named.

The facts

Issued
Jul 30, 1989, 7:35 PM MDT (01:35 UTC)
Expired
Jul 30, 1989, 8:30 PM MDT
In force
55 min
Issued by
NWS Great Falls, MT
Area
Whole counties

County Fergus 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 (KTFX), launched 00:00Z, 1.6 hours before the alert went out and 106 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 1989-07-31Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 29 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 00:00Z on 1989-07-31The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 31 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
29 J/kg
Mixed-layer CIN
-386 J/kg
Mixed-layer LCL
3636 m above ground
0-6 km bulk shear
24 kt
0-1 km storm-relative helicity
31 m²/s²
0-3 km storm-relative helicity
109 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 KGTF 310136
SVRGTF
MTC027-310230-
 
BULLETIN - IMMEDIATE BROADCAST REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE GREAT FALLS MT
735 PM MDT SUN JUL 30 1989
 
THE NATIONAL WEATHER SERVICE IN GREAT FALLS HAS ISSUED A
SEVERE THUNDERSTORM WARNING EFFECTIVE UNTIL  830 PM MDT
FOR PEOPLE IN THE FOLLOWING COUNTY...
 
IN  MONTANA
          ...WESTERN FERGUS ...INCLUDING LEWISTOWN
 
 
AT 728 PM MDT...ABOUT 15 MILES WEST OF LEWISTOWN...WINDS WERE CLOCKED
AT 46 GUSTING TO 61 MPH. HEAVY RAINS HAVE ALSO BEEN ASSOCIATED WITH
THIS STORM SYSTEM WHICH IS MOVING EAST ABOUT 20 MPH.
 
RESIDENTS IN WESTERN FERGUS COUNTY SHOULD BE ON THE ALERT FOR DAMAGING
WINDS...POSSIBLE LARGE HEAIL AND HEAVY RAIN ALONG WITH DEADLY
LIGHTNING.
 
 
SEVERE THUNDERSTORMS PRODUCE DAMAGING WIND IN EXCESS OF 55
MPH...DESTRUCTIVE HAIL...DEADLY LIGHTNING...AND VERY HEAVY RAIN.
FOR YOUR PROTECTION MOVE TO AN INTERIOR ROOM ON THE LOWEST FLOOR
OF YOUR HOME OR BUSINESS.  HEAVY RAINS FLOOD ROADS QUICKLY SO
DON'T 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.

In the hours before

Special weather statement, Jul 30, 5:48 PM MDT, 1 hour 47 minutes before
SPECIAL WEATHER STATEMENT...CORRECTION...3RD PARAGPH
NATIONAL WEATHER SERVICE GREAT FALLS, MT
546 PM MDT SUN JUL 30 1989

...SEVERE THUNDERSTORM WATCH MUCH OF WESTERN MONTANA EAST OF THE
DIVIDE TONIGHT UNTIL 10 PM...

AN AREA OF STRONG THUNDERSTORMS BOUNDED BY A LINE FROM 35 MILES WEST OF
LEWISTOWN TO GREAT FALLS THEN WEST TO THE DIVIDE AND SOUTH TO HELENA...
IS SHOWN BY RADAR AND SATELLITE THIS EVENING. THUNDERSTORM TOPS HAVE
BEEN MEASURED BY RADAR TO BETWEEN 45 AND 50 THOUSAND FEET BETWEEN GREAT
FALLS AND LEWISTOWN.
THE MAIN CONCENTRATION OF STORM CELLS IS ON A NORTH/SOUTH LINE FROM
NEAR CHOTEAU THROUGH HELENA TO DILLON. THESE STORMS ARE MOVING IN A
NORTHEASTERLY DIRECTION AROUND 35 MPH.

AT 530 PM TOWNSEND...SOUTHEAST OF HELENA...REPORTED WINDS TO 45 MPH.
HAIL NEAR 1 INCH IN DIAMETER FELL JUST SOUTH OF LINCOLN MONTANA.

RESIDENTS IN THE WATCH AREA SHOULD PAY CLOSE ATTENTION TO TONIGHTS
THUNDERSTORM ACTIVITY AS DAMAGING WINDS...LARGE HAIL...HEAVY RAIN AND
DEADLY LIGHTNING ARE ALL POSSIBLE IN AND AROUND THE WATCH AREA.

BE PREPARED TO TAKE SHELTER IF ANY OF THESE CONDITIONS ARE OBSERVED.
END...
Special weather statement, Jul 30, 6:30 PM MDT, 1 hour 5 minutes before
SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE HELENA, MT
630 PM MDT SUN JUL 30 1989

SEVERE THUNDERSTORM WARNING FOR HELENA...TOWNSEND AND DEER LODGE EXPIRES...

...SEVERE THUNDERSTORM WATCH CONTINUES FOR MUCH OF WESTERN MONTANA EAST
OF THE DIVIDE TONIGHT UNTIL 10 PM...

THE SEVERE THUNDERSTORM WARNING FOR JEFFERSON...BROADWATER...POWELL...
LEWIS AND CLARK...AND MEAGHER COUNTIES EXPIRED AT 615 PM MDT THIS SUNDAY
EVENING.

THE THUNDERSTORMS MOVED NORTHEAST INTO CASCADE COUNTY MONTANA AND A
WARNING HAS BEEN ISSUED FOR THAT COUNTY UNTIL 800 PM MDT THIS EVENING.

THE SEVERE THUNDERSTORM WATCH IS STILL IN EFFECT UNTIL 10 PM MDT..HOWEVER.

NEW THUNDERSTORMS ARE FORMING IN A SCATTERED BAND ALONG THE CONTINENTAL
DIVIDE.  PERSONS IN THE ENTIRE WATCH AREA SHOULD CONTINUE TO MONTIOR
WEATHER CONDITIONS UNTIL THE WATCH EXPIRES OR IS CANCELLED.
<
AT 625 PM MDT...NATIONAL WEATHER SERVICE RADAR AND LIGHTNING
CHARTS INDICATED NEW THUNDERSTORMS FROM JUST WEST LINCOLN EXTENDING
SOUTH TO NEAR BUTTE..IN MONTANA.  THE INDIVIDUAL THUNDERSTORMS WERE
MOVING TO THE NORTHEAST AT 30 MILES AN HOUR.

PERSONS SHOULD BE PREPARED FOR POSSIBLE LARGE HAIL...DAMAGING
WINDS AND DANGEROUS LIGHTNING STRIKECS TO GROUND OBJECTS AS THE
THUNDERSTORMS MOVE NORTHEAST ACROSS SOUTHWEST MONTANA.

BE PREPARED TO TAKE SHELTER IF ANY OF THESE CONDITIONS ARE OBSERVED.

MHOON
Special weather statement, Jul 30, 6:32 PM MDT, 1 hour 3 minutes before
SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE HELENA, MT
625 PM MDT SUN JUL 30 1989

...SEVERE THUNERSTORM FOR HELENA...TOWNSEND AND DEER LODGE EXPIRES...

...SEVERE THUNDERSTORM WATCH CONTINUES FOR MUCH OF WESTERN MONTANA EAST
OF THE DIVIDE TONIGHT UNTIL 10 PM...

THE SEVERE THUNDERSTORM WARNING FOR JEFFERSON...BROADWATER...POWELL...
LEWIS AND CLARK...AND MEAGHER COUNTIES EXPIRED AT 615 PM MDT THIS SUNDAY
EVENING.

THE THUNDERSTORMS MOVED NORTHEAST INTO CASCADE COUNTY MONTANA AND A
WARNING HAS BEEN ISSUED FOR THAT COUNTY UNTIL 800 PM MDT THIS EVENING.

THE SEVERE THUNDERSTORM WATCH IS STILL IN EFFECT UNTIL 10 PM MDT..HOWEVER.

NEW THUNDERSTORMS ARE FORMING IN A SCATTERED BAND ALONG THE CONTINENTAL
DIVIDE.  PERSONS IN THE ENTIRE WATCH AREA SHOULD CONTINUE TO MONTIOR
WEATHER CONDITIONS UNTIL THE WATCH EXPIRES OR IS CANCELLED.
<
AT 625 PM MDT...NATIONAL WEATHER SERVICE RADAR AND LIGHTING
CHARTS INDICATED NEW THUNDERSTORMS FROM WEST LINCOLN EXTENDING
SOUTH TO NEAR BUTTE.  THE INDIVIDUAL THUNDERSTORMS WERE MOVING
TO THE NORTHEAST AT 30 MILES AN HOUR.

PERSONS SHOULD BE PREPARED FOR POSSIBLE LARGE HAIL...DAMAGING
WINDS AND DANGEROUS LIGHTNING STRIKES TO GROUND OBJECTS AS T@HE
THUNDERSTORMS MOVE NORTHEAST ACROSS SOUTHWEST MONTANA.

BE PREPARED TO TAKE SHELTER IF ANY OF THESE CONDITIONS ARE OBSERVED.

MHOON
Special weather statement, Jul 30, 7:28 PM MDT, 7 minutes before
SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE HELENA, MT
730 PM MDT SUN JUL 30 1989

...SEVERE THUNDERSTORM WATCH CONTINUES FOR MUCH OF WESTERN MONTANA EAST
OF THE DIVIDE TONIGHT UNTIL 10 PM...

AT 7:25 PM MDT THIS SUNDAY EVENING...NATIONAL WEATHER SERVICE RADAR
AND LIGHTNING DEPICTION CHARTS WERE INDICATING SCATTERED THUNDERSTORMS
TO THE FAR NORTHWEST OF HELENA IN NORTHERN POWELL AND NORTHERN LEWIS
AND CLARK COUNTIES OF MONTANA.  THESE THUNDERSTORMS WERE MOVING TO
THE NORTHEAST AT ABOUT 30 MILES AN HOUR.

OTHER THUNDERSTORMS WERE IN SCATTERED BAND FROM GREAT FALLS SOUTHEAST
INTO MEAGHER AND JEFFERSON COUNTIES.  THEY WERE ALSO MOVING TO THE
NORTHEAST AT 30 MILES AN HOUR.

A SEVERE THUNDERSTORM CONTINUES FOR THE AREA UNTIL 1000 PM MDT THIS
SUNDAY.
<
PERSONS SHOULD BE PREPARED FOR POSSIBLE LARGE HAIL...DAMAGING
WINDS AND DANGEROUS LIGHTNING STRIKES TO GROUND OBJECTS AS THE
THUNDERSTORMS MOVE NORTHEAST ACROSS SOUTHWEST MONTANA.v

BE PREPARED TO TAKE SHELTER IF ANY OF THESE CONDITIONS ARE OBSERVED.

MHOON
Local storm report, Jul 30, 7:30 PM MDT, 5 minutes before
STORM REPORT
NATIONAL WEATHER SERVICE GREAT FALLS, MT
724 PM MDT SUN JUL 30 1989

645 PM MDT...NEIHARD MONTANA...45MI SE GTF...MARBLE SIZED HAIL.

WIND EVENTS...
1856 PM...35 W LWT...54G 69 MPH
1855 PMy...NE GEYSER/45SE GTF/...36G 46MPH

WSFO GREAT FALLS
Special weather statement, Jul 30, 7:30 PM MDT, 5 minutes before
SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE HELENA, MT
730 PM MDT SUN JUL 30 1989

...SEVERE THUNDERSTORM WATCH CONTINUES FOR MUCH OF WESTERN MONTANA EAST
OF THE DIVIDE TONIGHT UNTIL 10 PM...

AT 7:25 PM MDT THIS SUNDAY EVENING...NATIONAL WEATHER SERVICE RADAR
AND LIGHTNING DEPICTION CHARTS WERE INDICATING SCATTERED THUNDERSTORMS
TO THE FAR NORTHWEST OF HELENA IN NORTHERN POWELL AND NORTHERN LEWIS
AND CLARK COUNTIES OF MONTANA.  THESE THUNDERSTORMS WERE MOVING TO
THE NORTHEAST AT ABOUT 30 MILES AN HOUR.

OTHER THUNDERSTORMS WERE IN SCATTERED BAND FROM GREAT FALLS SOUTHEAST
INTO MEAGHER AND JEFFERSON COUNTIES.  THEY WERE ALSO MOVING TO THE
NORTHEAST AT 30 MILES AN HOUR.

A SEVERE THUNDERSTORM WATCH CONTINUES FOR THE AREA UNTIL 1000 PM MDT THIS
SUNDAY.
<
PERSONS SHOULD BE PREPARED FOR POSSIBLE LARGE HAIL...DAMAGING
WINDS AND DANGEROUS LIGHTNING STRIKES TO GROUND OBJECTS AS THE
THUNDERSTORMS MOVE NORTHEAST ACROSS SOUTHWEST MO{NTANA.

BE PREPARED TO TAKE SHELTER IF ANY OF THESE CONDITIONS ARE OBSERVED.

MHOON

The office that day

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

IssuedProductOfficeCountiesLasted
Jul 30, 6:01 PM MDTSevere Thunderstorm WarningTFXCascade56 min

Nearby

Severe Thunderstorm Warnings in Montana, 1989Every severe thunderstorm warning in 1989

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.