Alert archive / Montana / Severe Thunderstorm Warnings in 2001

Severe Thunderstorm Warning 84, NWS Great Falls, MT

August 4, 2001Judith Basin County, Montana

NWS Great Falls, MT issued this severe thunderstorm warning at Aug 4, 2001, 3:39 PM MDT for Judith Basin County, Montana. It was in force for 66 min. 1 report came from 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, with what was reported inside it.

The facts

Issued: Aug 4, 2001, 3:39 PM MDT (21:39 UTC)
Expired: Aug 4, 2001, 4:45 PM MDT
In force: 66 min
Issued by: NWS Great Falls, MT
Area: Whole counties; the outline is the Mesonet’s reconstruction

County Judith Basin County, MT

The radar

The Great Falls radar (KTFX), 56 km from the middle of the area, began a volume at 21:40 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.

What was reported inside it

Time	Report	Where	Remark
Aug 4, 3:40 PM MDT	Hail 0.75	Raynesford, MT	Actual event location Raynesford 6 N (or Belt 6 SE) along Judith Basin/Cascade county line.

NCEI Storm Data entries that began inside the alert's area while it was in force. Before 2003 the local storm report archive is thin, so this is the record of what happened rather than what was phoned in.

The watch it was issued in

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

Issued	Product	Office	Lasted
Aug 4, 2:00 PM MDT	Severe Thunderstorm Watch	SPC	5 hr

The nearest sounding before it

Great_falls, MT (KTFX), launched 12:00Z, 9.7 hours before the alert went out and 9 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: 38 J/kg
Mixed-layer CIN: -272 J/kg
Mixed-layer LCL: 2483 m above ground
0-6 km bulk shear: 30 kt
0-1 km storm-relative helicity: -70 m²/s²
0-3 km storm-relative helicity: -33 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 042140
SVRGTF

MTC045-042245-

BULLETIN - EAS ACTIVATION REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE GREAT FALLS MT
339 PM MDT SAT AUG 4 2001

THE NATIONAL WEATHER SERVICE IN GREAT FALLS HAS ISSUED A

* SEVERE THUNDERSTORM WARNING FOR...
    NORTHWESTERN JUDITH BASIN COUNTY IN CENTRAL MONTANA   

* UNTIL 445 PM MDT

* AT 335 PM MDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A
  SEVERE THUNDERSTORM OVER RAYNESFORD...OR ABOUT 26 MILES NORTHWEST
  OF STANFORD...MOVING NORTHEAST AT 35 MPH.

* THE SEVERE THUNDERSTORM WILL BE NEAR...
RURAL NORTHWESTERN JUDITH BASIN COUNTY AT 350 PM MDT 

VERY LARGE HAIL IS 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 700 PM MDT
SATURDAY EVENING FOR CENTRAL MONTANA.

LAT...LON 4732 11090 4719 11071 4748 11025 4761 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 Aug 4, 3:00 PM MDT, 39 minutes earlier.

Area forecast discussion, Aug 4, 3:00 PM MDT, 39 minutes before

SOUTHWEST AND NORTH CENTRAL MONTANA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREAT FALLS MT
3 PM MDT SAT AUG 4 2001

THUNDERSTORMS FORMING ALONG BACK EDGE OF DRY SLOT...PER WATER VAPOR
IMAGERY...A FAVORED LOCATION.  IN COORD WITH SPC AND OTHER MT
OFFICES...SVR TSTM WATCH ISSUED TILL 7 PM.  AXIS OF S/W STILL WEST OF
MT AND WILL TRAVERSE CWA BETWEEN 00-06Z.  THREAT OF DEEP CONVECTION
CONTINUES... NOW TILL ABOUT 01Z...THEN MAINLY SCATTERED SHOWERS TILL
MIDNIGHT. BEYOND THAT...MODELS IN FAIR AGREEMENT.  NEXT COUPLE OF
DAYS...UPPER RIDGE BUILDS BACK INTO MT....FLOW BECOMES DRIER AND MORE
WESTERLY.  QUITE WARM WITH LITTLE THREAT OF PCPN.  MIELKE.

EXTENDED FORECAST DISCUSSION...
RIDGE WILL CONTINUE WITH SOME DECREASE IN HEIGHTS BY WED. DO EXPECT
A LITTLE MORE TROFFING BY LATER IN THE PERIOD...SO THIS SHOULD KEEP
IT WARM THROUGH TUESDAY. WITH THE DECREASE IN HEIGHTS...TEMPS WILL
COOLE INTO THE 70S AND 80S WITH SCATTERED SHOWERS/TSTMS.

CCF NUMBERS
GTF UU 056 087 053 090 055 014001
CTB UU 052 082 052 085 053 013001
HLN UU 055 088 055 092 055 014101
BZN UU 052 090 052 093 054 014001
WEY UU 044 082 042 085 045 015111
DLN UU 048 086 050 089 051 014001
HVR UU 062 090 057 095 057 014001
LWT UU 056 087 056 090 056 014201

The office that day

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

Issued	Product	Office	Counties	Lasted
Aug 4, 1:17 PM MDT	Severe Thunderstorm Warning	TFX	Beaverhead	28 min
Aug 4, 1:28 PM MDT	Severe Thunderstorm Warning	TFX	Cascade, Lewis and Clark	47 min
Aug 4, 2:15 PM MDT	Severe Thunderstorm Warning	TFX	Cascade	60 min
Aug 4, 2:18 PM MDT	Severe Thunderstorm Warning	TFX	Jefferson	27 min
Aug 4, 3:12 PM MDT	Severe Thunderstorm Warning	TFX	Lewis and Clark	63 min
Aug 4, 3:49 PM MDT	Severe Thunderstorm Warning	TFX	Cascade	26 min
Aug 4, 3:59 PM MDT	Severe Thunderstorm Warning	TFX	Broadwater	31 min
Aug 4, 4:00 PM MDT	Severe Thunderstorm Warning	TFX	Meagher	30 min
Aug 4, 4:09 PM MDT	Severe Thunderstorm Warning	TFX	Cascade	51 min
Aug 4, 4:43 PM MDT	Severe Thunderstorm Warning	TFX	Cascade	32 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; verification from NCEI's Storm Data; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.