Alert archive / Montana / Severe Thunderstorm Warnings in 2001

Severe Thunderstorm Warning 46, NWS Great Falls, MT

July 16, 2001Jefferson County, Lewis and Clark County, Montana

NWS Great Falls, MT issued this severe thunderstorm warning at Jul 16, 2001, 2:53 PM MDT for Jefferson County, Lewis and Clark County, Montana. It was in force for 37 min. 2 reports 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
Jul 16, 2001, 2:53 PM MDT (20:53 UTC)
Expired
Jul 16, 2001, 3:30 PM MDT
In force
37 min
Issued by
NWS Great Falls, MT
Area
Whole counties; the outline is the Mesonet’s reconstruction

Counties Jefferson County, MT, Lewis and Clark County, MT

What was reported inside it

TimeReportWhereRemark
Jul 16, 3:05 PM MDTHail 0.75Helena, MTReported by spotter in Helena.
Jul 16, 3:15 PM MDTHail 0.75Wolf Creek, MTActual event location Wolf Creek 8 NW.

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.

IssuedProductOfficeLasted
Jul 16, 1:45 PM MDTSevere Thunderstorm WatchSPC5 hr

The nearest sounding before it

Great_falls, MT (KTFX), launched 12:00Z, 8.9 hours before the alert went out and 146 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 12:00Z on 2001-07-16Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 0 joules per kilogram.LCL10008507005003002001001 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 12:00Z on 2001-07-16The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 15 square meters per square second.1939Sfc1 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
0 J/kg
Mixed-layer CIN
No buoyant parcel
Mixed-layer LCL
1797 m above ground
0-6 km bulk shear
17 kt
0-1 km storm-relative helicity
15 m²/s²
0-3 km storm-relative helicity
56 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 162054
SVRGTF

MTC043-049-162130-

BULLETIN - EAS ACTIVATION REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE GREAT FALLS MT
253 PM MDT MON JUL 16 2001

THE NATIONAL WEATHER SERVICE IN GREAT FALLS HAS ISSUED A

* SEVERE THUNDERSTORM WARNING FOR...
  EXTREME NORTHEASTERN JEFFERSON COUNTY IN SOUTHWEST MONTANA
  SOUTHEASTERN LEWIS AND CLARK COUNTY IN WEST CENTRAL MONTANA
  THIS INCLUDES THE CITY OF HELENA

* UNTIL 330 PM MDT

* AT 248 PM MDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A
  LINE OF SEVERE THUNDERSTORMS FROM 24 MILES NORTHWEST OF HELENA TO 8
  MILES SOUTHWEST OF HELENA...MOVING NORTHEAST AT 20 MPH.

* SEVERE THUNDERSTORMS WILL BE NEAR...
  OVER MONTANA CITY...HELENA AT 310 PM MDT
  OVER EAST HELENA AT 320 PM MDT

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 THUNDER=STORM WATCH REMAINS IN EFFECT UNTIL 700 PM MDT MONDAY
EVENING FOR WESTERN MONTANA.

LAT...LON 4681 11254 4650 11220 4651 11179 4711 11204

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 16, 9:20 AM MDT, 5 hours 33 minutes earlier.

Area forecast discussion, Jul 16, 9:20 AM MDT, 5 hours 33 minutes before
SOUTHWEST AND NORTH CENTRAL MONTANA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREAT FALLS MT
920 AM MDT MON JUL 16 2001

...UPDATE PLANNED FOR THIS MORNING...
UPPER LEVEL LOW PRESSURE TROF OVER THE WEST COAST IS SLOWLY MOVING
EAST. SATELLITE INDICATES A SHORTWAVE OVER THE OR/ID BORDER AND
MODELS INIT THIS WELL. SPC HAS MOST OF CWA IN SLIGHT RISK
CATEGORY. NOTHING REAL STRONG TO INDICATE SEVERE WEATHER...ALTHOUGH
COMPARED TO YESTERDAY...MOST INDICES SLIGHTLY MORE FAVORABLE FOR
SEVERE. CAPE AND LI MORE UNSTABLE...HELICITY INCREASES...AND BULK
RICHARDSON IS FORECAST IN MID 20S COMPARED TO 100S YESTERDAY. UPPER
LEVEL SUPPORT LOOKS BETTER WITH CONTINUED VEERING AND SOME INCREASE
IN SPEEDS ALOFT. CONVECTION WILL DEVELOP FROM HEATING ALONE ALTHOUGH
TIMING OF SHORT WAVE WILL BE IMPORTANT FOR SEVERE...AND THIS
CURRENTLY APPEARS TO BE A LATE AFTERNOON EVENT. WILL DROP A FEW TEMPS
IN THE SW OTHERWISE GENERALLY LEAVE FORECAST AS IS.  ZELZER

EXTENDED...LATEST AVN BROUGHT A CLOSED UPPER LOW THROUGH THE NRN
ZONES LATER THU NIGHT INTO FRI. LATEST AVAILABLE ECMWF WAS WEAKER
AND SLOWER WITH THIS SHORTWAVE. JUST CHECKED LATEST MRF AND IT
IS SLOWER AND WEAKER THAN THE AVN WITH THE SHORTWAVE. BASED ON
LATEST ECMWF AND MRF CURRENT FORECAST POPS FOR THU AND FRI LOOK
A LITTLE WEAK SO WILL BUMP THEM UP TO THE CHANCE CATEGORY.

CCF NUMBERS
GTF BB 080/050 076/048 080 04441
CTB BN 077/047 072/045 076 04221H
HLN TE 079/053 077/051 080 04552
BZN TE 080/050 079/050 081 04553
WEY TE 078/046 075/046 077 04553
DLN TE 074/048 076/046 077 04532
HVR BB 090/055 085/053 090 04161
LWT BE 081/051 076/051 080 04362

The office that day

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

IssuedProductOfficeCountiesLasted
Jul 16, 2:58 PM MDTSevere Thunderstorm WarningTFXLewis and Clark32 min
Jul 16, 3:53 PM MDTSevere Thunderstorm WarningTFXCascade37 min
Jul 16, 3:55 PM MDTSevere Thunderstorm WarningTFXCascade, Meagher35 min
Jul 16, 4:28 PM MDTSevere Thunderstorm WarningTFXCascade, Judith Basin, Meagher47 min
Jul 16, 4:34 PM MDTSevere Thunderstorm WarningTFXGlacier, Pondera, Toole41 min
Jul 16, 5:18 PM MDTSevere Thunderstorm WarningTFXToole42 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; verification from NCEI's Storm Data; the sounding from the Mesonet's radiosonde archive.