Alert archive / Montana / Severe Thunderstorm Watches in 1998

Severe Thunderstorm Watch 721

July 3, 199813 counties in Montana

The Storm Prediction Center issued this severe thunderstorm watch at Jul 3, 1998, 7:00 PM MDT for 13 counties in Montana. It was in force for 5 hr.

The area

The outline as issued.

The facts

Issued: Jul 3, 1998, 7:00 PM MDT (01:00 UTC)
Expired: Jul 4, 1998, 12:00 AM MDT
In force: 5 hr
Issued by: the Storm Prediction Center

Counties Broadwater County, MT, Cascade County, MT, Chouteau County, MT, Glacier County, MT, Hill County, MT, Judith Basin County, MT, Lewis and Clark County, MT, Liberty County, MT, Meagher County, MT, Pondera County, MT, Teton County, MT, Toole County, MT, Wheatland County, MT

The radar

The Great Falls radar (KTFX), 65 km from the middle of the area, began a volume at 01:00 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.

Warnings issued inside it

21 tornado, severe thunderstorm and flash flood warnings for its counties while it was in force.

Issued	Product	Office	Counties	Lasted
Jul 3, 7:10 PM MDT	Severe Thunderstorm Warning	TFX	Glacier	35 min
Jul 3, 7:22 PM MDT	Severe Thunderstorm Warning	TFX	Cascade, Lewis and Clark	43 min
Jul 3, 7:48 PM MDT	Severe Thunderstorm Warning	TFX	Cascade	47 min
Jul 3, 7:57 PM MDT	Severe Thunderstorm Warning	TFX	Chouteau, Teton	48 min
Jul 3, 8:01 PM MDT	Severe Thunderstorm Warning	TFX	Lewis and Clark	59 min
Jul 3, 8:06 PM MDT	Severe Thunderstorm Warning	TFX	Meagher	29 min
Jul 3, 8:09 PM MDT	Severe Thunderstorm Warning	TFX	Fergus, Judith Basin	61 min
Jul 3, 8:16 PM MDT	Severe Thunderstorm Warning	TFX	Liberty, Pondera, Toole	64 min
Jul 3, 8:17 PM MDT	Tornado Warning	TFX	Cascade, Chouteau	18 min
Jul 3, 8:36 PM MDT	Severe Thunderstorm Warning	TFX	Cascade, Chouteau, Teton	49 min
Jul 3, 8:36 PM MDT	Severe Thunderstorm Warning	TFX	Liberty, Pondera, Toole	49 min
Jul 3, 8:39 PM MDT	Severe Thunderstorm Warning	TFX	Fergus, Judith Basin, Meagher	51 min
Jul 3, 8:59 PM MDT	Tornado Warning	TFX	Cascade, Meagher	21 min
Jul 3, 9:00 PM MDT	Flash Flood Warning	TFX	Chouteau, Fergus, Judith Basin	3 hr
Jul 3, 9:06 PM MDT	Severe Thunderstorm Warning	TFX	Broadwater, Jefferson	49 min
Jul 3, 9:26 PM MDT	Severe Thunderstorm Warning	TFX	Chouteau, Fergus, Hill, Judith Basin, Liberty	49 min
Jul 3, 9:30 PM MDT	Severe Thunderstorm Warning	TFX	Broadwater, Meagher	50 min
Jul 3, 10:07 PM MDT	Severe Thunderstorm Warning	TFX	Chouteau, Fergus, Judith Basin	58 min
Jul 3, 10:07 PM MDT	Severe Thunderstorm Warning	TFX	Blaine, Hill	58 min
Jul 3, 10:40 PM MDT	Severe Thunderstorm Warning	TFX	Meagher	50 min
Jul 3, 11:10 PM MDT	Severe Thunderstorm Warning	TFX	Judith Basin	60 min

The nearest sounding before it

Great_falls, MT (KTFX), launched 00:00Z, 1.0 hours before the alert went out and 60 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-p

Temperature in red, dew point in green, the mixed-layer parcel dashed.

Hodograph

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: 1560 J/kg
Mixed-layer CIN: -2 J/kg
Mixed-layer LCL: 1121 m above ground
0-6 km bulk shear: 49 kt
0-1 km storm-relative helicity: 58 m²/s²
0-3 km storm-relative helicity: 310 m²/s²
Significant tornado parameter: 1.9
Supercell composite: 8.8

Open this sounding in Storm Lab

The text

As transmitted, in the capitals the NWS used until 2016.

823 
WWUS9 KMKC 040026
SEL1  
MKC WW 040026
MTZ000-040600-

URGENT- IMMEDIATE BROADCAST REQUESTED
SEVERE THUNDERSTORM WATCH NUMBER 721
STORM PREDICTION CENTER NORMAN OK
626 PM MDT FRI JUL 3 1998

THE STORM PREDICTION CENTER HAS ISSUED A
SEVERE THUNDERSTORM WATCH FOR PORTIONS OF

   WESTERN MONTANA                            

EFFECTIVE THIS FRIDAY NIGHT AND SATURDAY MORNING FROM 700 PM UNTIL
MIDNIGHT MDT.

HAIL TO 2 INCHES IN DIAMETER...THUNDERSTORM WIND GUSTS TO 80
MPH...AND DANGEROUS LIGHTNING ARE POSSIBLE IN THESE AREAS.

THE SEVERE THUNDERSTORM WATCH AREA IS ALONG AND 70 STATUTE MILES
EAST AND WEST OF A LINE FROM 50 MILES NORTHEAST OF CUT BANK MONTANA
TO 45 MILES WEST SOUTHWEST OF HARLOWTON MONTANA.

REMEMBER...A SEVERE THUNDERSTORM WATCH MEANS CONDITIONS ARE
FAVORABLE FOR SEVERE THUNDERSTORMS IN AND CLOSE TO THE WATCH AREA. 
PERSONS IN THESE AREAS SHOULD BE ON THE LOOKOUT FOR THREATENING
WEATHER CONDITIONS AND LISTEN FOR LATER STATEMENTS AND POSSIBLE
WARNINGS.

OTHER WATCH INFORMATION...THIS SEVERE THUNDERSTORM WATCH REPLACES
SEVERE THUNDERSTORM WATCH NUMBER 719.  WATCH NUMBER 719 WILL NOT BE
IN EFFECT AFTER 700 PM MDT.  CONTINUE...WW 720...

DISCUSSION...LINE OF STRONG/SEVERE STORMS EXPECTED TO CONTINUE E OF
MOUNTAINS  INTO PLAINS OF WESTERN MT WHERE UPSLOPE AND UNSTABLE
AIRMASS IN PLACE.  WIND PROFILES AND CAPES TO 2000 J/KG  SUPPORT
STORMS CONTINUING TO BE SEVERE  WITH AND AHEAD OF LINE SEVERAL MORE
HOURS.


AVIATION...A FEW SEVERE THUNDERSTORMS WITH HAIL SURFACE AND ALOFT
TO 2 INCHES.  EXTREME TURBULENCE AND SURFACE WIND GUSTS TO 70
KNOTS.  A FEW CUMULONIMBI WITH MAXIMUM TOPS TO 500.  MEAN STORM
MOTION VECTOR 23030.


...HALES

490,1100 461,1091 461,1121 490,1130

SPC that day

Everything else SPC issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Jul 3, 10:45 PM MDT	Severe Thunderstorm Watch	SPC	Blaine, Fergus, Garfield, Petroleum, Phillips, Valley	4 hr
Jul 4, 2:30 PM MDT	Severe Thunderstorm Watch	SPC	Beaverhead, Blaine, Broadwater, Cascade, Chouteau, Deer Lodge and 19 more	7 hr
Jul 4, 5:30 PM MDT	Tornado Watch	SPC	Big Horn, Carbon, Daniels, Garfield, McCone, Musselshell and 6 more	6 hr

Nearby

Severe Thunderstorm Watches in Montana, 1998 Every severe thunderstorm watch in 1998

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.