Alert archive / Montana / Severe Thunderstorm Warnings in 2001

Severe Thunderstorm Warning 40, NWS Great Falls, MT

July 13, 2001Cascade County, Judith Basin County, Montana

NWS Great Falls, MT issued this severe thunderstorm warning at Jul 13, 2001, 6:42 PM MDT for Cascade County, Judith Basin 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, 6:42 PM MDT (00:42 UTC)
Expired
Jul 13, 2001, 7:30 PM MDT
In force
48 min
Issued by
NWS Great Falls, MT
Area
Whole counties; the outline is the Mesonet’s reconstruction

Counties Cascade County, MT, Judith Basin County, MT

The radar

The Great Falls radar (KTFX), 57 km from the middle of the area, began a volume at 00:42 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 watch it was issued in

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

IssuedProductOfficeLasted
Jul 13, 1:30 PM MDTSevere Thunderstorm WatchSPC6 hr
Jul 13, 2:15 PM MDTSevere Thunderstorm WatchSPC5 hr

The nearest sounding before it

Great_falls, MT (KTFX), launched 00:00Z, 0.7 hours before the alert went out and 31 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-pSkew-T log-p diagram, Great_falls, MT at 00:00Z on 2001-07-14Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 113 joules per kilogram.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°0°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Great_falls, MT at 00:00Z on 2001-07-14The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 21 square meters per square second.19395878Sfc1 km3 km6 km9 kmRMLM
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
113 J/kg
Mixed-layer CIN
-40 J/kg
Mixed-layer LCL
2628 m above ground
0-6 km bulk shear
40 kt
0-1 km storm-relative helicity
21 m²/s²
0-3 km storm-relative helicity
59 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.2

Open this sounding in Storm Lab

The text

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

000 
WUUS55 KTFX 140041
SVRGTF

MTC013-045-140130-

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

THE NATIONAL WEATHER SERVICE IN GREAT FALLS HAS ISSUED A

* SEVERE THUNDERSTORM WARNING FOR...
  EASTERN CASCADE COUNTY IN CENTRAL MONTANA
  NORTHERN JUDITH BASIN COUNTY IN CENTRAL MONTANA

* UNTIL 730 PM MDT

* AT 635 PM MDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A   
SEVERE THUNDERSTORM 30 MILES SOUTH OF BELT...OR ABOUT 10 MILES 
SOUTHWEST OF MONARCH.

* THE SEVERE THUNDERSTORM WILL BE NEAR...
MONARCH AND NEIHART AT 650 PM MDT
STANFORD IN JUDITH BASIN COUNTY AT 715 PM MDT

STRONG WINDS TO 70 MPH AND ONE INCH DIAMETER HAIL 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 4744 11109 4727 11104 4704 11103 4699 11092 4692 11084 4701 
11050 4709 11026 4720 11029 4735 11043 4737 11063 X4740 11072 4740 11082 
4743 11091

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, 4 hours earlier.

Area forecast discussion, Jul 13, 2:42 PM MDT, 4 hours 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.

IssuedProductOfficeCountiesLasted
Jul 13, 6:05 PM MDTSevere Thunderstorm WarningTFXCascade, Meagher40 min
Jul 14, 5:35 PM MDTSevere Thunderstorm WarningTFXFergus40 min

Nearby

Severe Thunderstorm Warnings in Montana, 2001Every 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; radar from the NEXRAD Level II archive.