Alert archive / Montana / Severe Thunderstorm Warnings in 2001

Severe Thunderstorm Warning 77, NWS Great Falls, MT

July 28, 2001Hill County, Montana

NWS Great Falls, MT issued this severe thunderstorm warning at Jul 28, 2001, 4:55 PM MDT for Hill 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 outline the Iowa Environmental Mesonet reconstructed for it; the warning itself named whole counties.

The facts

Issued: Jul 28, 2001, 4:55 PM MDT (22:55 UTC)
Expired: Jul 28, 2001, 5:55 PM MDT
In force: 60 min
Issued by: NWS Great Falls, MT
Area: Whole counties; the outline is the Mesonet’s reconstruction

County Hill 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

Great_falls, MT (KTFX), launched 12:00Z, 10.9 hours before the alert went out and 102 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: 0 J/kg
Mixed-layer CIN: No buoyant parcel
Mixed-layer LCL: 3192 m above ground
0-6 km bulk shear: 25 kt
0-1 km storm-relative helicity: -11 m²/s²
0-3 km storm-relative helicity: 77 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 
WUUS55 KTFX 282259
SVRGTF
MTC041-282355-

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

THE NATIONAL WEATHER SERVICE IN GREAT FALLS HAS ISSUED A

* SEVERE THUNDERSTORM WARNING FOR...
  HILL COUNTY IN NORTH CENTRAL MONTANA

* UNTIL 555 PM MDT

* AT 455 PM MDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A
  CLUSTER OF SEVERE THUNDERSTORMS FROM 16 MILES SOUTHWEST OF GILDFORD TO
  11 MILES WEST OF BOX ELDER...OR FROM 19 MILES EAST OF CHESTER TO 14
  MILES NORTHWEST OF BIG SANDY...MOVING NORTHEAST AROUND 30 MPH.

* THE SEVERE THUNDERSTORMS WILL BE OVER RURAL CENTRAL HILL COUNTY THROUGH 
  530 PM...INCLUDING AREAS AROUND FRESNO RESERVOIR....AND EASTERN HILL COUNTY
  NEAR HAVRE BY 555 PM.

THESE SEVERE THUNDERSTORMS HAVE THE POTENTIAL OF DAMAGING WINDS TO 70 MPH.

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 4837 11074 4831 11047 4831 10985 4843 10986
 ?         4899 10971 4899 11050

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 10 minutes earlier.

Area forecast discussion, Jul 28, 2:45 PM MDT, 2 hours 10 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, 5:01 PM MDT	Severe Thunderstorm Warning	TFX	Blaine	44 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.