Alert archive / Montana / Severe Thunderstorm Warnings in 2000

Severe Thunderstorm Warning 92, NWS Great Falls, MT

July 20, 2000Chouteau County, Montana

NWS Great Falls, MT issued this severe thunderstorm warning at Jul 20, 2000, 6:03 PM MDT for Chouteau County, Montana. It was in force for 27 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 20, 2000, 6:03 PM MDT (00:03 UTC)
Expired: Jul 20, 2000, 6:30 PM MDT
In force: 27 min
Issued by: NWS Great Falls, MT
Area: Whole counties

County Chouteau County, MT

The radar

The Great Falls radar (KTFX), 85 km from the middle of the area, began a volume at 00:04 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 00:00Z, 0.1 hours before the alert went out and 48 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: 207 J/kg
Mixed-layer CIN: -20 J/kg
Mixed-layer LCL: 2946 m above ground
0-6 km bulk shear: 19 kt
0-1 km storm-relative helicity: -17 m²/s²
0-3 km storm-relative helicity: 59 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.

836 
WUUS55 KTFX 210006
SVRGTF
MTC015-210030-

BULLETIN - EAS ACTIVATION REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE GREAT FALLS MT
603 PM MDT THU JUL 20 2000

THE NATIONAL WEATHER SERVICE IN GREAT FALLS HAS ISSUED A

* SEVERE THUNDERSTORM WARNING FOR...
  SOUTHWEST CHOUTEAU COUNTY IN NORTH CENTRAL MONTANA

* UNTIL 630 PM MDT

* AT 554 PM MDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A
  SEVERE THUNDERSTORM 8 MILES NORTHWEST OF HIGHWOOD...OR ABOUT 18
  MILES SOUTHWEST OF FORT BENTON...MOVING SOUTHEAST AT 15 MPH.

* THE SEVERE THUNDERSTORM WILL BE NEAR...HIGHWOOD AT 625 PM MDT. 
THIS THUNDERSTORM WILL PRODUCE LARGE HAIL UP TO AN INCH IN SIZE AND 
WIND GUSTS TO 60 MPH. HEAVY RAIN IS ALSO LIKELY WITH THIS 
THUNDERSTORM.

REPORT SEVERE WEATHER TO THE NEAREST LAW ENFORCEMENT AGENCY. THEY
WILL RELAY YOUR REPORT TO THE NATIONAL WEATHER SERVICE FORECAST
OFFICE IN GREAT FALLS.

$$
LAT...LON 4777 11094 4761 11105 4748 11069 4761 11055

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.

NWS Great Falls, MT wrote its last area forecast discussion before this severe thunderstorm warning went out at Jul 20, 2:45 PM MDT, 3 hours 18 minutes earlier.

Area forecast discussion, Jul 20, 2:45 PM MDT, 3 hours 18 minutes before

SOUTHWEST AND NORTH CENTRAL MONTANA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREAT FALLS MT
245 PM MDT THU JUL 20 2000

SHORT WAVE TROF MOVING ACROSS SWRN MT ENCOUNTERING UNSTABLE AIR AND
DEWPOINTS IN THE 50S...RESULTING IN DEVELOPING TSTMS ACROSS MUCH OF
SRN/CNTRL/ERN CWA.  STORMS OVER SRN/CNTRL PORTION OF CWA EXPECTED TO
REMAIN BELOW SEVERE CRITERIA. HOWEVER A NEARLY STATIONARY SFC TROF OVER
CNTRL MT AIDING AS FOCAL POINT FOR STRONG TO A FEW POSSIBLY SEVERE
STORMS INTO THIS EVENING OVER ERN PORTIONS OF CWA. IN ADDITION LIFTED
INDICES THIS AFTN -4 TO -6 WITH CAPES 1000 TO 1500 J/KG ACROSS EASTERN
CWA WILL HELP FUEL STRONG CONVECTION.  EXPECT NEARLY SAME SETUP FOR
FRIDAY AS UPPER RIDGE OVER PAC NW STRUGGLING TO BUILD EASTWARD.

MODELS FAIRLY CONSISTENT BUILDING RIDGE AXIS OVER MUCH OF CWA ON
SATURDAY WITH WARMING AND DRYING CONDITIONS EXPECTED.  HIGHS IN THE MID
90S AT MANY LOCATIONS PROBABLE FOR SATURDAY.  JOHNSON

EXTENDED...FINALLY GOOD AGREEMENT IN MEDIUM RANGE MODELS. MRF/ECMWF/LAST
PERIODS OF UKMET ALL SHOW UPPER LEVEL SHORTWAVE TROUGH FLATTENING STRONG
UPPER RIDGE AND MOVING INTO NORTHWESTERN MONTANA ON SUNDAY. MRF/ECMWF
THEN WEAKEN TROUGH AND RAPIDLY MOVE IT ALONG HI-LINE MONDAY AND INTO
DAKOTAS/UPPER MIDWEST BY TUESDAY...YIELDING A MORE WESTERLY FLOW ALOFT.
FOR TUESDAY...THOUGH...MRF SWITCHES FROM DEEP UPPER LOW OFF BC COAST TO
ANOTHER RAPIDLY SOUTHEASTWARD-MOVING SHORTWAVE TROUGH REACHING
NORTHWESTERN MONTANA FOR TUESDAY...IN GOOD AGREEMENT WITH ECMWF. SURFACE
PATTERN FORECAST INDICATES A COLD FRONT MOVING THROUGH THE TFX CWA LATE
SUNDAY...REACHING THE DAKOTAS ON MONDAY. TEMPERATURES SHOULD STAY WARM
SUNDAY BEFORE THE COLD FRONT MOVES THROUGH...THEN THEY SHOULD COOL FOR
MONDAY AND TUESDAY AS THICKNESSES DROP BEHIND THE FRONT. BEST CHANCE FOR
PRECIPITATION ON SUNDAY WITH GUSTY WEST WINDS. MONDAY SHOULD STILL SEE
SOME WINDS ALONG THE ROCKY MOUNTAIN FRONT...WITH LESS OF A CHANCE.
TUESDAY SHOULD SEE A BETTER CHANCE NORTHWESTERN ZONES FOR AFTERNOON
SHOWERS AND THUNDERSTORMS WITH APPROACHING SHORTWAVE.  COULSTON

CCF NUMBERS
GTF BU 055/091 056/094 059 122221
CTB BU 053/087 054/090 056 122111
HLN BU 054/091 054/095 059 123332
BZN BU 050/090 050/094 051 123332
WEY TB 041/079 041/087 043 124332
DLN BU 048/085 049/090 050 122222
HVR TB 055/092 056/095 059 124441
LWT TB 051/085 054/090 056 124441

Nearby

Severe Thunderstorm Warnings in Montana, 2000 Every severe thunderstorm warning in 2000

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.