Alert archive / Montana / Severe Thunderstorm Warnings in 1997

Severe Thunderstorm Warning 46, NWS Great Falls, MT

July 19, 1997Lewis and Clark County, Montana

NWS Great Falls, MT issued this severe thunderstorm warning at Jul 19, 1997, 5:45 PM MDT for Lewis and Clark County, Montana. It was in force for 60 min. No storm report in the archive falls inside the area while it was in force.

The area

The counties it named.

The facts

Issued
Jul 19, 1997, 5:45 PM MDT (23:45 UTC)
Expired
Jul 19, 1997, 6:45 PM MDT
In force
60 min
Issued by
NWS Great Falls, MT
Area
Whole counties

County Lewis and Clark County, MT

The radar

The Great Falls radar (KTFX), 85 km from the middle of the area, began a volume at 23:47 UTC, the scan nearest the moment this went out.

Open the radar archive at this moment

The archived warnings, watches and discussions in force at that minute are drawn over the scan, this one among them.

The nearest sounding before it

Great_falls, MT (KTFX), launched 12:00Z, 11.8 hours before the alert went out and 140 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 1997-07-19Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 122 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 1997-07-19The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 44 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
122 J/kg
Mixed-layer CIN
-92 J/kg
Mixed-layer LCL
1225 m above ground
0-6 km bulk shear
17 kt
0-1 km storm-relative helicity
44 m²/s²
0-3 km storm-relative helicity
51 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 192347 RRA
SVRGTF
MTC049-200045-
 
BULLETIN - IMMEDIATE BROADCAST REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE GREAT FALLS MT
545 PM MDT SAT JUL 19 1997
 
THE NATIONAL WEATHER SERVICE IN GREAT FALLS HAS ISSUED A
SEVERE THUNDERSTORM WARNING EFFECTIVE UNTIL  645 PM MDT
FOR PEOPLE IN THE FOLLOWING LOCATION...
 
IN SOUTHWEST MONTANA
 
   ...SOUTHERN LEWIS AND CLARK COUNTY
 
A LINE OF SEVERE THUNDERSTORMS OVER SOUTHERN LEWIS AND CLARK COUNTY HAS
PRODUCED MARBLE SIZE HAIL IN THE HELENA VALLEY. A HAM RADIO OPERATOR 5
MILES NORTH-NORTHEAST OF HELENA ALSO OBSERVED A FUNNEL CLOUD WITH THIS
STORM. THUNDERSTORMS IN THIS LINE CONTINUE TO INCREASE IN INTENSITY...
WITH HEAVY RAIN AND ONE INCH HAIL POSSzIBLE. THESE THUNDERSTORMS ARE
MOVING TOWARDS THE NORTH AT 10 TO 15 MPH.
 
&

The office that day

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

IssuedProductOfficeCountiesLasted
Jul 19, 5:00 PM MDTSevere Thunderstorm WarningTFXBroadwater, Jefferson60 min

Nearby

Severe Thunderstorm Warnings in Montana, 1997Every severe thunderstorm warning in 1997

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; radar from the NEXRAD Level II archive.