Alert archive / Montana / Severe Thunderstorm Warnings in 2001

Severe Thunderstorm Warning 78, NWS Great Falls, MT

July 28, 2001Blaine County, Montana

NWS Great Falls, MT issued this severe thunderstorm warning at Jul 28, 2001, 5:01 PM MDT for Blaine County, Montana. It was in force for 44 min. No storm report in the archive falls inside the area while it was in force.

The area

The outline the Iowa Environmental Mesonet reconstructed for it; the warning itself named whole counties.

The facts

Issued: Jul 28, 2001, 5:01 PM MDT (23:01 UTC)
Expired: Jul 28, 2001, 5:45 PM MDT
In force: 44 min
Issued by: NWS Great Falls, MT
Area: Whole counties; the outline is the Mesonet’s reconstruction

County Blaine County, MT

The watch it was issued in

The SPC watch in force over the same counties when this warning went out.

Issued	Product	Office	Lasted
Jul 28, 3:00 PM MDT	Severe Thunderstorm Watch	SPC	6 hr

The nearest sounding before it

Glasgow Intl Airport, MT (KGGW), launched 12:00Z, 11.0 hours before the alert went out and 182 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: 1024 J/kg
Mixed-layer CIN: -214 J/kg
Mixed-layer LCL: 2081 m above ground
0-6 km bulk shear: 37 kt
0-1 km storm-relative helicity: 219 m²/s²
0-3 km storm-relative helicity: 284 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 1.0

Open this sounding in Storm Lab

The text

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

000 
WUUS55 KTFX 282304
SVRGTF
MTC005-282345-

BULLETIN - EAS ACTIVATION REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE GREAT FALLS MT
501 PM MDT SAT JUL 28 2001

THE NATIONAL WEATHER SERVICE IN GREAT FALLS HAS ISSUED A

* SEVERE THUNDERSTORM WARNING FOR...
  NORTHERN BLAINE COUNTY IN NORTH CENTRAL MONTANA

* UNTIL 545 PM MDT

* AT 452 PM MDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A 
  CLUSTER OF SEVERE THUNDERSTORMS IN THE VICINITIES OF FORT          
  BELKNAP...HARLEM...AND ZURICH...MOVING NORTHEAST AT 30 MPH.

* SEVERE THUNDERSTORMS WILL BE NEAR...
  OVER TURNER AT 540 PM MDT

STRONG AND DAMAGING WINDS ARE LIKELY FROM THIS STORM...BUT THERE WILL
BE LITTLE RAIN. TAKE COVER IN A STURDY STRUCTURE UNTIL THE STORM
PASSES.

VERY LARGE HAIL UP TO 1 INCH IN DIAMETER IS ALSO POSSIBLE WITH THIS 
SEVERE THUNDERSTORM. IF YOU ARE IN THE PATH OF THE STORM...PUT YOUR 
CAR IN A GARAGE AND MOVE TO A SUBSTANTIAL SHELTER.

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

A SEVERE THUNDERSTORM WATCH REMAINS IN EFFECT UNTIL 900 PM MDT
SATURDAY EVENING FOR NORTH CENTRAL MONTANA.

LAT...LON 4877 10942 4835 10851 4883 10827 4906 10908

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 28, 2:45 PM MDT, 2 hours 16 minutes earlier.

Area forecast discussion, Jul 28, 2:45 PM MDT, 2 hours 16 minutes before

SOUTHWEST AND NORTH CENTRAL MONTANA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREAT FALLS MT
245 PM MDT SAT JUL 28 2001

STRONG NEGATIVELY-TILTED UPPER LEVEL TROUGH SWINGING INTO NORTHERN
IDAHO/WESTERN MT THIS AFTERNOON. TROUGH WILL QUICKLY SWEEP ACROSS NRN
MT AND INTO SRN SASK TONIGHT AS IT ENCOUNTERS STRONG UPPER RIDGE OVER
GREAT PLAINS. ASSOCIATED COLD FRONT WILL LIKEWISE RAPIDLY MOVE
ACROSS STATE. DIFFLUENT FLOW ALOFT AHEAD OF TROUGH TOGETHER WITH
FRONT LEFT QUADRANT OF UPPER JET OVER CENTRAL MONTANA THIS EVENING
WILL ENHANCE UPWARD VERTICAL MOTION NE HALF OF GTF CWFA. PRE-FRONTAL
SURFACE TROUGH OVER CENTRAL MONTANA PROVIDING FOCUS FOR CONVERGENCE.
WARM...AND SLIGHTLY MOIST...SOUTHERLY FLOW OVER ERN MT WILL
DESTABILIZE THE AIRMASS AHEAD OF COLD FRONT. MEANWHILE...COOL AIR
BEHIND THE COLD FRONT WILL ENHANCE DOWNWARD MOTION RESULTING IN GOOD
LOW-LEVEL CONVERGENCE ALONG FRONT...FURTHER ENHANCING THUNDERSTORM
DEVELOPMENT.

SPECIAL 18Z TFX SOUNDING SHOWS INVERTED-V CONFIGURATION INDICATIVE OF
STRONG WINDS AND BELIEVE GREATEST THREAT WILL BE POSSIBILITY OF
STRONG DOWNBURST WINDS. MOST UNSTABLE AIR WILL BE OVER EASTERN
PORTION OF GTF CWFA...18Z GGW SOUNDING SHOWS GOOD VERTICAL SHEAR AND
INSTABILITY. THEREFORE EXPECT BEST CHANCE FOR SEVERE WEATHER THIS
AREA AND AM CONCERNED WITH POSSIBILITY OF SUPERCELL DEVELOPMENT...
PRIMARILY OVER BLAINE AND FERGUS COUNTIES. SPC HAS THIS PORTION
OF GTF CWFA UNDER SLIGHT RISK OF SEVERE THUNDERSTORMS WHICH SEEMS
REASONABLE CONSIDERING CIRCUMSTANCES. RAPID SCAN WILL COMMENCE AT 21Z
AND EXPECT WATCH TO BE FORTHCOMING. BEHIND THE FRONT...DAYTIME HIGH
TEMPERATURES COOL 10 TO 15 DEGREES SUNDAY AND THEN CHANGE LITTLE
MONDAY.

EXTENDED DISCUSSION...MODELS ARE IS BASIC AGREEMENT IN THE OVERALL
PATTERN KEEPING THE RIDGE OVER THE CENTRAL PLAINS AND GENERAL
TROUGHING OVER THE PACIFIC NORTHWEST. THIS WILL KEEP THE AREA IN
THE PERSISTENT SOUTHWEST FLOW. DAY 3 LOOKS UNSETTLED ACROSS THE AREA
AS UPPER LEVEL ENERGY SWINGS THROUGH BUT PATTERN FAVORS A DRIER
SCENARIO FOR DAYS 4 AND 5. HOWEVER...THE CHANCE OF AFTERNOON
CONVECTION CAN NOT BE RULED OUT. THE PATTERN RETURNS TO A MORE
FAVORABLE FLOW ON DAYS 6 AND 7 FOR A BETTER CHANCE OF SHOWERS
AND THUNDERSTORMS. FEEL THE BEST SOLUTION WILL BE TO BROAD-BRUSH THE
AREA FOR THE ENTIRE PERIOD...PRETTY MUCH WHAT THE GOING FORECAST IS
NOW. TEMPS WILL BE FAIRLY CONSISTENT REGION WIDE.  GOUDSWARD

GTF BB 050/076 047/076 045 06300
CTB BB 050/072 045/070 044 06100
HLN BB 052/078 048/078 047 06211
BZN BB 044/078 042/076 044 06311
WEY BB 040/070 038/070 040 06200
DLN BB 043/075 042/075 044 06210
HVR BB 050/080 048/077 046 06611
2LWT BB 047/074 045/074 045 06611

The office that day

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

Issued	Product	Office	Counties	Lasted
Jul 28, 3:06 PM MDT	Severe Thunderstorm Warning	TFX	Cascade, Chouteau, Judith Basin	54 min
Jul 28, 3:33 PM MDT	Severe Thunderstorm Warning	TFX	Blaine, Chouteau, Fergus, Hill	57 min
Jul 28, 3:51 PM MDT	Severe Thunderstorm Warning	TFX	Blaine, Chouteau, Fergus	54 min
Jul 28, 4:15 PM MDT	Severe Thunderstorm Warning	TFX	Chouteau, Hill	60 min
Jul 28, 4:55 PM MDT	Severe Thunderstorm Warning	TFX	Hill	60 min

Nearby

Severe Thunderstorm Warnings in Montana, 2001 Every severe thunderstorm warning in 2001

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.