Alert archive / Montana / Severe Thunderstorm Warnings in 2001

Severe Thunderstorm Warning 62, NWS Great Falls, MT

July 21, 2001Chouteau County, Montana

NWS Great Falls, MT issued this severe thunderstorm warning at Jul 21, 2001, 2:41 PM MDT for Chouteau County, Montana. It was in force for 49 min. 1 report came from inside the area while it was in force.

The area

The counties it named, with what was reported inside it.

The facts

Issued: Jul 21, 2001, 2:41 PM MDT (20:41 UTC)
Expired: Jul 21, 2001, 3:30 PM MDT
In force: 49 min
Issued by: NWS Great Falls, MT
Area: Whole counties

County Chouteau County, MT

What was reported inside it

Time	Report	Where	Remark
Jul 21, 3:15 PM MDT	Hail 1.5	Iliad, MT	Actual event location Iliad 3 E.

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 nearest sounding before it

Great_falls, MT (KTFX), launched 12:00Z, 8.7 hours before the alert went out and 48 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: 21 J/kg
Mixed-layer CIN: -341 J/kg
Mixed-layer LCL: 1692 m above ground
0-6 km bulk shear: 33 kt
0-1 km storm-relative helicity: -53 m²/s²
0-3 km storm-relative helicity: 75 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 212042
SVRGTF

MTC015-212130-

BULLETIN - EAS ACTIVATION REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE GREAT FALLS MT
241 PM MDT SAT JUL 21 2001

THE NATIONAL WEATHER SERVICE IN GREAT FALLS HAS ISSUED A

* SEVERE THUNDERSTORM WARNING FOR...
  SOUTHEASTERN CHOUTEAU COUNTY IN NORTH CENTRAL MONTANA

* UNTIL 330 PM MDT

* AT 235 PM MDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A
  SEVERE THUNDERSTORM OVER GERALDINE...OR ABOUT 27 MILES NORTH OF   
STANFORD...MOVING NORTHEAST AT 20 MPH.

* THE SEVERE THUNDERSTORM WILL CONTINUE TO AFFECT AREAS NEAR 
GERALDINE THROUGH 3 PM...AND IT WILL BE OVER RURAL SOUTHEASTERN 
CHOUTEAU COUNTY AT 315 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.

BRUSDA

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 21, 9:35 AM MDT, 5 hours 6 minutes earlier.

Area forecast discussion, Jul 21, 9:35 AM MDT, 5 hours 6 minutes before

SOUTHWEST AND NORTH CENTRAL MONTANA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREAT FALLS MT
935 AM MDT SAT JUL 21 2001
...UPDATES PLANNED FOR ZONES AND STATE...
LATEST ETA/NGM INDICATE A SHORTWAVE MOVING THROUGH NW ZONES THE
REMAINDER OF THIS MORNING INTO EARLY AFTERNOON. RADAR/SATELLITE
IMAGERY INDICATE A LITTLE BIT OF CONVECTIVE ACTIVITY OVER NW MT.
WILL TONE DOWN 60 PCT POPS TO 30 PCT POPS IN THIS AREA. BASED ON
LATEST ETA/NGM MAIN FOCUS OF ACTIVITY TODAY INTO TONIGHT WILL BE FROM
SW MT TO CENTRAL MT. THIS IS WHERE BEST LOW LEVEL CONVERGENCE AND
MOST UNSTABLE AIRMASS WILL BE. THERMODYNAMIC PARAMETERS INDICATE A
POTENTIAL FOR SEVERE WEATHER. PROBLEM IS THERE APPEARS TO BE A LACK
OF DYNAMICS. LATEST ETA/NGM ZIP A VERY WEAK SHORTWAVE OVER THE AREA
THIS EVENING. JET DYNAMICS DO NOT LOOK AS FAVORABLE AS WAS FORECAST
IN FRIDAYS 12Z MODEL RUNS. DO NOT DOUBT THERE WILL BE SOME SEVERE
WEATHER TODAY IN FORECAST AREA...FEEL ACTIVITY WILL BE QUITE
ISOLATED.

.EXTENDED...
LATEST MRF DEPICTS ANOTHER TROUGH DIGGING TO THE WEST ON MONDAY AND
TUESDAY...AND GENERAL TREND HAS BEEN TO SLOW DOWN THE TRANSITION TO A
DRIER ZONAL FLOW. WILL INTRODUCE A CHANCE OF SHOWERS ON TUESDAY AND
WEDNESDAY. TROUGH FROM THE GULF OF ALASKA NUZZLES INTO THE NORTHERN
ZONES ON THURSDAY FOR A FAIRLY WINDY SITUATION WITH A CHANCE OF
SHOWERS. SOUTHWEST STAYS IN A FAIRLY DRY ZONAL FLOW ON THURSDAY AND
FRIDAY. POMEROY

CCF NUMBERS
GTF TB 080 053 078 050 075 19641
CTB TB 077 050 075 048 074 19631
HLN TB 082 053 080 051 076 19641
BZN TB 083 048 080 048 074 19441
WEY EB 078 045 075 042 071 19330
DLN TB 079 049 077 045 076 19531
HVR TB 088 060 088 055 085 19641
LWT TB 077 053 077 050 071 19651-

In the hours before

Special weather statement, Jul 21, 10:30 AM MDT, 4 hours 11 minutes before

MTZ011>015-047-050>055-212230-

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE GREAT FALLS MT
1030 AM MDT SAT JUL 21 2001

...STRONG THUNDERSTORMS POSSIBLE AGAIN THIS AFTERNOON AND EVENING
FOR CENTRAL MONTANA...

HAIL AND GUSTY WINDS WILL AGAIN BE POSSIBLE WITH THUNDERSTORMS IN AN
AREA EAST OF A LINE FROM HAVRE TO GREAT FALLS TO HELENA TO DILLON.
SOME THUNDERSTORMS...MAINLY OVER BLAINE...FERGUS...JUDITH
BASIN...AND MEAGHER COUNTIES COULD SEE HAIL TO 1 INCH IN
DIAMETER...WIND GUSTS TO 60 MPH...AND BRIEF HEAVY RAIN.

A VERY UNSTABLE AIRMASS CONTINUES OVER CENTRAL MONTANA. ONCE AGAIN
THUNDERSTORMS WILL DEVELOP OVER CENTRAL AND SOUTHWEST MONTANA THIS
AFTERNOON AND SPREAD NORTHEAST OVERNIGHT. DUE TO A LACK OF A
SIGNIFICANT WEATHER DISTURBANCE ALOFT...ANY SEVERE THUDNERSTORMS
THAT DEVELOP THIS AFTERNOON AND EVENING SHOULD BE ISOLATED.

ANYONE WITH OUTDOOR ACTIVITIES PLANNED THIS AFTERNOON AND EVENING
OVER CENTRAL MONTANA SHOULD LISTEN TO NOAA WEATHER RADIO...OR
ANOTHER MEDIA OUTLET...TO KEEP POSTED ON ANY WATCHES OR WARNINGS
THAT MAY BE ISSUED.

THIS INFORMATION CAN ALSO BE OBTAINED FROM OUR WEB SITE AT:
HTTP://WWW.WRH.NOAA.GOV/GREATFALLS

BLANK

The office that day

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

Issued	Product	Office	Counties	Lasted
Jul 20, 8:08 PM MDT	Severe Thunderstorm Warning	TFX	Fergus	67 min
Jul 21, 3:32 PM MDT	Severe Thunderstorm Warning	TFX	Judith Basin	43 min
Jul 21, 3:54 PM MDT	Severe Thunderstorm Warning	TFX	Fergus	51 min
Jul 21, 4:33 PM MDT	Severe Thunderstorm Warning	TFX	Judith Basin	42 min
Jul 21, 4:45 PM MDT	Severe Thunderstorm Warning	TFX	Blaine	45 min
Jul 21, 5:04 PM MDT	Severe Thunderstorm Warning	TFX	Fergus	56 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.