Alert archive / Montana / Severe Thunderstorm Warnings in 2001

Severe Thunderstorm Warning 38, NWS Great Falls, MT

July 13, 2001Jefferson County, Montana

NWS Great Falls, MT issued this severe thunderstorm warning at Jul 13, 2001, 5:57 PM MDT for Jefferson County, Montana. It was in force for 48 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 13, 2001, 5:57 PM MDT (23:57 UTC)
Expired: Jul 13, 2001, 6:45 PM MDT
In force: 48 min
Issued by: NWS Great Falls, MT
Area: Whole counties; the outline is the Mesonet’s reconstruction

County Jefferson 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 13, 2:15 PM MDT	Severe Thunderstorm Watch	SPC	5 hr

The nearest sounding before it

Great_falls, MT (KTFX), launched 12:00Z, 12.0 hours before the alert went out and 222 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: 100 J/kg
Mixed-layer CIN: -251 J/kg
Mixed-layer LCL: 1561 m above ground
0-6 km bulk shear: 32 kt
0-1 km storm-relative helicity: 27 m²/s²
0-3 km storm-relative helicity: 41 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 132358
SVRGTF
MTC043-140045-

BULLETIN - EAS ACTIVATION REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE GREAT FALLS MT
557 PM MDT FRI JUL 13 2001

THE NATIONAL WEATHER SERVICE IN GREAT FALLS HAS ISSUED A

* SEVERE THUNDERSTORM WARNING FOR...
  SOUTHERN JEFFERSON COUNTY IN SOUTHWEST MONTANA

* UNTIL 645 PM MDT

* AT 555 PM MDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A
  SEVERE THUNDERSTORM 30 MILES WEST OF WHITEHALL...OR ABOUT 10 MILES
  SOUTH OF BUTTE...MOVING NORTHEAST AT 35 MPH.

* THE SEVERE THUNDERSTORM WILL BE NEAR...
  WHITEHALL AT 630 PM MDT

STRONG WINDS TO 60 MPH ARE POSSIBLE WITH THIS SEVERE THUNDERSTORM. IF 
YOU ARE IN THE PATH OF THE STORM...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. 

LAT...LON 4581 11283 4566 11271 4589 11203 4587 11175
          4617 11200

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 13, 2:42 PM MDT, 3 hours 15 minutes earlier.

Area forecast discussion, Jul 13, 2:42 PM MDT, 3 hours 15 minutes before

SOUTHWEST AND NORTH CENTRAL MONTANA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREAT FALLS MT
242 PM MDT FRI JUL 13 2001

SYNOPSIS...THUNDERSTORMS EXPECTED ACROSS CWA THIS EVENING WITH SEVERE
THUNDERSTORM WATCHES IN EFFECT UNTIL 700 PM MDT. SCATTERED
THUNDERSTORMS WILL DEVELOP AGAIN SATURDAY AFTERNOON. LITTLE CHANGE
EXPECTED IN TEMPERATURES.

DISCUSSION...PERSISTENT HIGH PRESSURE RIDGE CENTERED OVER THE
SOUTHERN CONUS WITH A LOW PRESSURE TROUGH OFF THE WEST COAST.
RESULTANT SOUTHWEST FLOW OF MOIST...UNSTABLE AIR INTO CWA CREATING
THUNDERSTORMS AGAIN THIS AFTERNOON WITH POSSIBILITY OF SEVERE
THUNDERSTORMS. DYNAMICS IN PLACE...LARGE AREA OF LOWER LEVEL
CONVERGENCE COUPLED WITH UPPER LEVEL DIVERGENCE CENTERED OVER CWA...
DISTURBANCE PUSHING THROUGH...JET MAX PASSING OVER...NEGATIVE LI/S
BLANKETING CWA WITH AREAS BETWEEN -4 AND -6...CAPES 1000 J/KG AND
HIGHER...AND TIME SECTIONS SHOWING STRONG OMEGA AROUND 00Z.
FORECASTED SOUNDINGS ADVERTISE PRECIPITABLE WATER INCREASING FROM
AROUND THREE/QUARTERS OF AN INCH THIS MORNING TO OVER AN INCH THROUGH
THE EVENING. SOME THUNDERSTORMS EXPECTED TO CREATE STRONG WIND...HAIL
AND HEAVY RAIN...THUS TWO SEVERE THUNDERSTORM WATCHES HAVE BEEN
ISSUED FOR THE CWA. ACTIVITY FOR CWA SHOULD DIMINISH AFTER SUNSET AS
DISTURBANCES PUSH INTO EASTERN MT AND DYNAMICS WEAKEN. LITTLE CHANGE
IN PATTERN SATURDAY...WITH SOUTHWEST FLOW CONTINUING. DYNAMICS NOT
QUITE AS IMPRESSIVE HOWEVER...AND WILL PUT POPS IN SCATTERED
CATEGORY. MOS GUIDANCE WANTS TO COOL TEMPERATURES SEVERAL DEGREES
SATURDAY. THOUGH FLOW SLIGHTLY MORE WESTERLY DO NOT EXPECT MUCH
CHANGE AND WILL KEEP FORECASTS WITHIN A DEGREE OR TWO OF TODAY.

.EXTENDED...
ALL OF THE EXTENDED MODELS SUGGEST LITTLE CHANGE TO THE PATTERN
MONDAY THROUGH NEXT FRIDAY.  AN UPPER LOW REMAINS PARKED OVER THE
PAC NORTHWEST AND SOUTHERN BC THRU WED THEN BEGINS SLOWLY FILLING
AND LIFTING NORTHEAST.  HOWEVER...FLOW CONTINUES TO BE OUT OF THE
SOUTHWEST TOWARDS THE END OF THE WEEK.  THEREFORE... EXPECT
SCATTERED THUNDERSTORMS THRU PERIOD WITH NEAR NORMAL TEMPS. MIELKE

CCF NUMBERS
GTF TB 054 084 053 083 054 036334
CTB TB 051 083 050 083 051 035223
HLN zTT 056 085 055 086 055 036345
BZN TT 050 085 051 086 051 036345
WEY TT 053 078 046 080 048 036345
DLN TT 051 084 050 085 050 034344
HVR TB 058 088 059 087 058 036222
LWT TB 054 084 054 085 053 036344

The office that day

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

Issued	Product	Office	Counties	Lasted
Jul 12, 7:25 PM MDT	Severe Thunderstorm Warning	TFX	Hill	50 min
Jul 12, 7:43 PM MDT	Severe Thunderstorm Warning	TFX	Blaine	32 min
Jul 12, 7:48 PM MDT	Severe Thunderstorm Warning	TFX	Fergus	27 min
Jul 13, 12:58 PM MDT	Severe Thunderstorm Warning	TFX	Judith Basin	32 min
Jul 13, 1:32 PM MDT	Severe Thunderstorm Warning	TFX	Judith Basin	28 min
Jul 13, 2:52 PM MDT	Severe Thunderstorm Warning	TFX	Gallatin	28 min
Jul 13, 3:21 PM MDT	Severe Thunderstorm Warning	TFX	Fergus	24 min
Jul 13, 5:20 PM MDT	Severe Thunderstorm Warning	TFX	Lewis and Clark	40 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.