Alert archive / Montana / Tornado Warnings in 2008

Tornado Warning 2, NWS Great Falls, MT

May 20, 2008Chouteau County, Montana

NWS Great Falls, MT issued this tornado warning at May 20, 2008, 8:40 PM MDT for Chouteau County, Montana. It was in force for 35 min. No storm report in the archive falls inside the area while it was in force.

The area

The outline as issued.

The facts

Issued
May 20, 2008, 8:40 PM MDT (02:40 UTC)
Expired
May 20, 2008, 9:15 PM MDT
In force
35 min
Issued by
NWS Great Falls, MT
Area
Storm-based polygon

County Chouteau County, MT

The radar

The Great Falls radar (KTFX), 89 km from the middle of the area, began a volume at 02:44 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 nearest sounding before it

Great_falls, MT (KTFX), launched 00:00Z, 2.7 hours before the alert went out and 61 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 2008-05-21Temperature 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°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Great_falls, MT at 00:00Z on 2008-05-21The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 127 square meters per square second.193958Sfc1 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
3180 m above ground
0-6 km bulk shear
51 kt
0-1 km storm-relative helicity
127 m²/s²
0-3 km storm-relative helicity
302 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 
WFUS55 KTFX 210240
TORTFX
MTC015-210315-
/O.NEW.KTFX.TO.W.0002.080521T0240Z-080521T0315Z/

BULLETIN - EAS ACTIVATION REQUESTED
TORNADO WARNING
NATIONAL WEATHER SERVICE GREAT FALLS MT
840 PM MDT TUE MAY 20 2008

THE NATIONAL WEATHER SERVICE IN GREAT FALLS HAS ISSUED A

* TORNADO WARNING FOR...
  CENTRAL CHOUTEAU COUNTY IN NORTH CENTRAL MONTANA...
  THIS INCLUDES THE CITY OF FORT BENTON...

* UNTIL 915 PM MDT

* AT 834 PM MDT...A THUNDERSTORM WITH A HISTORY OF PRODUCING
  TORNADOES WAS LOCATED NEAR FORT BENTON...MOVING EAST AT 43 MPH.

* LOCATIONS IN THE WARNING INCLUDE FORT BENTON AND LOMA.

IN ADDITION TO THE TORNADO...THIS STORM IS CAPABLE OF PRODUCING
QUARTER SIZE HAIL.

IN ADDITION TO THE TORNADO...THIS STORM IS CAPABLE OF PRODUCING 
STRAIGHT LINE WIND GUSTS TO 70 MPH.

THE SAFEST PLACE TO BE DURING A TORNADO IS IN A BASEMENT. GET UNDER A
WORKBENCH OR OTHER PIECE OF STURDY FURNITURE. IF NO BASEMENT IS
AVAILABLE...SEEK SHELTER ON THE LOWEST FLOOR OF THE BUILDING IN AN
INTERIOR HALLWAY OR ROOM SUCH AS A CLOSET. USE BLANKETS OR PILLOWS TO
COVER YOUR BODY AND ALWAYS STAY AWAY FROM WINDOWS.

IF IN MOBILE HOMES OR VEHICLES...EVACUATE THEM AND GET INSIDE A
SUBSTANTIAL SHELTER. IF NO SHELTER IS AVAILABLE...LIE FLAT IN THE
NEAREST DITCH OR OTHER LOW SPOT AND COVER YOUR HEAD WITH YOUR HANDS.

LAT...LON 4825 11052 4790 10996 4759 11060 4800 11073
      4805 11082
TIME...MOT...LOC 0240Z 252DEG 37KT 4784 11047

$$

COHEN/ZUMPFE
2 follow-up statements
000 
WWUS55 KTFX 210309
SVSTFX

SEVERE WEATHER STATEMENT
NATIONAL WEATHER SERVICE GREAT FALLS MT
909 PM MDT TUE MAY 20 2008

MTC015-210315-
/O.CON.KTFX.TO.W.0002.000000T0000Z-080521T0315Z/
CHOUTEAU MT-
909 PM MDT TUE MAY 20 2008

...A TORNADO WARNING REMAINS IN EFFECT UNTIL 915 PM MDT FOR CENTRAL
CHOUTEAU COUNTY...

AT 904 PM MDT...NATIONAL WEATHER SERVICE DOPPLER RADAR CONTINUED TO
INDICATE A TORNADO.  THIS TORNADO WAS LOCATED OVER CENTRAL CHOUTEAU
COUNTY...OR 18 MILES EAST OF FORT BENTON...MOVING NORTHEAST AT 37
MPH.

THE TORNADO WILL OTHERWISE REMAIN OVER MAINLY RURAL AREAS OF THE
INDICATED COUNTY.

THE SAFEST PLACE TO BE DURING A TORNADO IS IN A BASEMENT. GET UNDER A
WORKBENCH OR OTHER PIECE OF STURDY FURNITURE. IF NO BASEMENT IS
AVAILABLE...SEEK SHELTER ON THE LOWEST FLOOR OF THE BUILDING IN AN
INTERIOR HALLWAY OR ROOM SUCH AS A CLOSET. USE BLANKETS OR PILLOWS TO
COVER YOUR BODY AND ALWAYS STAY AWAY FROM WINDOWS.

IF IN MOBILE HOMES OR VEHICLES...EVACUATE THEM AND GET INSIDE A
SUBSTANTIAL SHELTER. IF NO SHELTER IS AVAILABLE...LIE FLAT IN THE
NEAREST DITCH OR OTHER LOW SPOT AND COVER YOUR HEAD WITH YOUR HANDS.

LAT...LON 4824 11052 4790 10998 4774 11027 4773 11032
      4760 11057 4764 11058 4765 11055 4768 11056
      4796 11043 4812 11065
TIME...MOT...LOC 0309Z 229DEG 32KT 4791 11023

$$

COHEN
000 
WWUS55 KTFX 210317
SVSTFX

SEVERE WEATHER STATEMENT
NATIONAL WEATHER SERVICE GREAT FALLS MT
917 PM MDT TUE MAY 20 2008

MTC015-210327-
/O.EXP.KTFX.TO.W.0002.000000T0000Z-080521T0315Z/
CHOUTEAU MT-
917 PM MDT TUE MAY 20 2008

...THE TORNADO WARNING FOR CENTRAL CHOUTEAU COUNTY HAS EXPIRED...

NATIONAL WEATHER SERVICE RADAR INDICATED THAT THE SEVERE THUNDERSTORM
THAT PROMPTED THE WARNING HAD WEAKENED AND WAS NO LONGER SEVERE...
THUS THE WARNING HAS BEEN ALLOWED TO EXPIRE.

RADAR INDICATED THAT HEAVY RAIN...SMALL HAIL...AND GUSTY WINDS WERE
STILL POSSIBLE FROM THE THUNDERSTORM.

LAT...LON 4824 11052 4790 10998 4774 11027 4773 11032
      4760 11057 4764 11058 4765 11055 4768 11056
      4796 11043 4812 11065
TIME...MOT...LOC 0309Z 229DEG 32KT 4791 11023

$$

COHEN

The office that day

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

IssuedProductOfficeCountiesLasted
May 20, 6:43 PM MDTSevere Thunderstorm WarningTFXGallatin, Madison47 min
May 20, 7:42 PM MDTSevere Thunderstorm WarningTFXCascade, Chouteau48 min
May 20, 8:11 PM MDTTornado WarningTFXChouteau34 min
May 20, 10:23 PM MDTSevere Thunderstorm WarningTFXBlaine, Chouteau, Fergus, Hill49 min
May 21, 12:28 PM MDTAreal Flood AdvisoryTFXBeaverhead2 hr
May 21, 2:31 PM MDTRiver Flood WarningTFXBeaverhead, Madison18 hr
May 21, 2:31 PM MDTRiver Flood WarningTFXGallatin5 days

Nearby

Tornado Warnings in Montana, 2008Every tornado warning in 2008Tornadoes in 2008

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.