Alert archive / Montana / Severe Thunderstorm Warnings in 2003

Severe Thunderstorm Warning 87, NWS Great Falls, MT

August 7, 2003Fergus County, Montana

NWS Great Falls, MT issued this severe thunderstorm warning at Aug 7, 2003, 4:35 PM MDT for Fergus County, Montana. It was in force for 55 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: Aug 7, 2003, 4:35 PM MDT (22:35 UTC)
Expired: Aug 7, 2003, 5:30 PM MDT
In force: 55 min
Issued by: NWS Great Falls, MT
Area: Counties, with a storm outline in the text

County Fergus County, MT

Did it verify

Not verified. The Iowa Environmental Mesonet's Cow found no qualifying storm report inside this severe thunderstorm warning while it was in force. That is not proof nothing happened: reports are thin where few people live.

Cow counts a report within 15 km of the polygon while the warning was in force: a tornado for a tornado warning; hail of 1 inch or more, a gust of 58 mph or more or wind damage for a severe thunderstorm warning; a flash flood report for a flash flood warning.

The watch it was issued in

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

Issued	Product	Office	Lasted
Aug 7, 3:45 PM MDT	Severe Thunderstorm Watch	SPC	6 hr

The nearest sounding before it

Great_falls, MT (KTFX), launched 12:00Z, 10.6 hours before the alert went out and 71 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: 0 J/kg
Mixed-layer CIN: No buoyant parcel
Mixed-layer LCL: 2439 m above ground
0-6 km bulk shear: 34 kt
0-1 km storm-relative helicity: -81 m²/s²
0-3 km storm-relative helicity: 39 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 072235
SVRTFX
MTC027-072330-

BULLETIN - EAS ACTIVATION REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE GREAT FALLS MT
434 PM MDT THU AUG 7 2003

THE NATIONAL WEATHER SERVICE IN GREAT FALLS HAS ISSUED A

* SEVERE THUNDERSTORM WARNING FOR...
  NORTHWESTERN FERGUS COUNTY IN CENTRAL MONTANA

* UNTIL 530 PM MDT

* AT 430 PM MDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A
  SEVERE THUNDERSTORM OVER EXTREME NORTHWESTERN FERGUS COUNTY...OR   
  ABOUT 15 MILES NORTH OF DENTON...MOVING NORTHEAST AT 15 MPH.

* THE SEVERE THUNDERSTORM WILL MOVE OVER...
  RURAL NORTHWESTERN FERGUS COUNTY THROUGH 450 PM MDT
  AND BE NEAR WINIFRED AT 515 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 THUNDERSTORM WATCH REMAINS IN EFFECT UNTIL 1000 PM MDT
THURSDAY EVENING FOR NORTH CENTRAL MONTANA.

LAT...LON 4763 10944 4738 10982 4754 10994 4755 10986
          4768 10984 4775 10963 4776 10952

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 Aug 7, 2:55 PM MDT, 1 hour 40 minutes earlier.

Area forecast discussion, Aug 7, 2:55 PM MDT, 1 hour 40 minutes before

SOUTHWEST AND NORTH CENTRAL MONTANA FORECAST
NATIONAL WEATHER SERVICE GREAT FALLS MT
255 PM MDT THU AUG 7 2003

.DISCUSSION...

TONIGHT...DEEP UPPER LEVEL LOW OFF THE PACIFIC NORTHWEST COAST AND
RIDGING OVER THE CENTRAL CONUS WITH SOUTHWEST FLOW ALOFT OVER MY
CWA. AIRMASS IS UNSTABLE...BUT LACKS A GOOD SOURCE OF DYNAMICS TO
INITIATE WIDESPREAD CONVECTION. MESO-ETA IS DEPICTING A VORTICITY
MAX MOVING FROM SOUTHWEST MONTANA THIS EVENING TO THE HI-LINE AND
GGWS CWA BY MORNING...BUT OTHER MODELS ARE NOT AS STRONG WITH THIS
FEATURE. WILL MENTION SCATTERED CONVECTION ALONG THE PATH OF THIS
SHORT WAVE...AND ISOLATED POPS ELSEWHERE. WILL ALSO MENTION GUSTY
WINDS WITH THUNDERSTORM ACTIVITY...BUT FEEL THE RISK OF SEVERE
WEATHER IS NOT EXTREME.

FRIDAY THROUGH SATURDAY...PATTERN REMAINS ESSENTIALLY UNCHANGED WITH
SOUTHWEST FLOW ALOFT OVER A DIURNALLY UNSTABLE AIRMASS. MODELS VARY
IN TIMING AND STRENGTH OF VORT LOBES THAT OCCASIONALLY MOVE OVER
THE CWA...SO WILL KEEP ONLY SLIGHT CHANCE POPS THROUGH THE PERIOD.
MPJ

SUNDAY THROUGH TUESDAY...STRONG UPPER LEVEL HIGH PRESSURE RIDGE
REMAINS CENTERED OVER FOUR CORNERS AREA WITH LOW PRESSURE TROUGH
CENTERED OFF PACIFIC NORTHWEST COAST. WESTERN AND CENTRAL MONTANA LIE
UNDER THE MOIST SOUTHWEST FLOW BETWEEN THE TWO WHILE EASTERN MONTANA
SITS UNDER THE NORTHERN PORTION OF THE RIDGE. SEVERAL WEAK
DISTURBANCES EMBEDDED IN THE SOUTHWEST FLOW WILL PUSH INTO MONTANA
DURING THE PERIOD CREATING THUNDERSTORMS OVER CWA...MAINLY DURING THE
AFTERNOON AND EVENING HOURS.

WEDNESDAY...UPPER TROUGH NUDGES INLAND...PUSHING RIDGE ONLY SLIGHTLY
TO THE EAST. INCOMING ENERGY ASSOCIATED WITH TROUGH IS WEAKENED...
AND THE PATTERN OF MAINLY WEAK DISTURBANCES PUSHING THROUGH THE CWA
CONTINUES FOR A CONTINUED CHANCE OF AFTERNOON AND EVENING
THUNDERSTORMS.

.CCF NUMBERS
GTF BB 056/092 057/090 061 14322
    UUUUB 091/055 088/060 088/058 088/054 078 221000000--
CTB BB 054/087 052/086 053 14322
    UBUBB 087/052 087/055 084/054 084/050 077 112000000--
HLN BU 059/093 058/091 061 14311
    BUBUB 092/055 089/058 086/056 086/051 078 111-----022
BZN BU 053/091 052/089 051 14222
    BUBBB 089/055 090/058 086/057 086/053 080 ----0-00022
WEY BU 047/083 043/082 044 14122
    BBBBB 082/050 083/051 076/051 076/049 077 11222211011
DLN BU 054/089 051/088 050 14211
    BBBBB 091/053 089/054 083/052 083/047 088 -1111122022
HVR BB 060/095 059/093 063 14222
    UBUUB 091/056 090/063 091/062 091/059 082 22200000000
LWT BB 058/090 056/087 058 14222
    UUUUU 089/057 091/061 087/060 087/057 082 22100000011

.TFX...NONE.

Hazardous weather outlook, Aug 7, 12:01 PM MDT, 4 hours 34 minutes before

MTZ008>015-044>055-080010-
HAZARDOUS WEATHER OUTLOOK...CORRECTED EXPIRATION TIME
NATIONAL WEATHER SERVICE GREAT FALLS MT
930 AM MDT THU AUG 7 2003

THIS HAZARDOUS WEATHER OUTLOOK IS FOR NORTH CENTRAL AND SOUTHWEST MONTANA

.DAY ONE...TODAY

ISOLATED THUNDERSTORMS ARE POSSIBLE THIS AFTERNOON AND EVENING. SOME
OF THESE STORMS MAY BE SEVERE...WITH DAMAGING WINDS AND HAIL.
LIGHTNING STRIKES MAY START FIRES.

.DAYS TWO THROUGH SEVEN...THURSDAY THROUGH TUESDAY

ISOLATED TO SCATTERED THUNDERSTORMS ARE EXPECTED TO DEVELOP FRIDAY
AND SATURDAY AFTERNOON AND EVENING ACROSS NORTH CENTRAL AND SOUTHWEST
MONTANA. SOME OF THESE STORMS COULD BECOME SEVERE WITH HAIL AND
DAMAGING WINDS THE MAIN THREAT.

WEATHER SPOTTERS ARE ENCOURAGED TO REPORT SIGNIFICANT WEATHER
CONDITIONS ACCORDING TO STANDARD OPERATING PROCEDURES.

In the hours before

Local storm report, Aug 7, 4:03 PM MDT, 32 minutes before

LOCAL STORM REPORT
NATIONAL WEATHER SERVICE GREAT FALLS MT
403 PM MDT THU AUG 7 2003

TIME(MDT)  .....EVENT  LOCATION..... ST   ...EVENT/REMARKS...........
           .....COUNTY LOCATION.....

0345 PM    1 SE SQUARE BUTTE         MT   0.25 INCH HAIL
08/07/03   CHOUTEAU

NNNN

Local storm report, Aug 7, 4:17 PM MDT, 18 minutes before

LOCAL STORM REPORT...UPDATED
NATIONAL WEATHER SERVICE GREAT FALLS MT
417 PM MDT THU AUG 7 2003

TIME(MDT)  .....EVENT  LOCATION..... ST   ...EVENT/REMARKS...........
           .....COUNTY LOCATION.....

0345 PM    1 SE SQUARE BUTTE         MT   0.25 INCH HAIL
08/07/03   CHOUTEAU

0410 PM    7 E SQUARE BUTTE          MT   0.25 INCH HAIL
08/07/03   CHOUTEAU

NNNN

Local storm report, Aug 7, 4:22 PM MDT, 13 minutes before

LOCAL STORM REPORT...UPDATED
NATIONAL WEATHER SERVICE GREAT FALLS MT
422 PM MDT THU AUG 7 2003

TIME(MDT)  .....EVENT  LOCATION..... ST   ...EVENT/REMARKS...........
           .....COUNTY LOCATION.....

0345 PM    1 SE SQUARE BUTTE         MT   0.25 INCH HAIL
08/07/03   CHOUTEAU

0400 PM    8 N COFFEE CREEK          MT   0.50 INCH HAIL
08/07/03   FERGUS

0410 PM    7 E SQUARE BUTTE          MT   0.25 INCH HAIL
08/07/03   CHOUTEAU

NNNN

The office that day

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

Issued	Product	Office	Counties	Lasted
Aug 6, 6:00 PM MDT	Severe Thunderstorm Warning	TFX	Fergus	60 min
Aug 6, 6:10 PM MDT	Severe Thunderstorm Warning	TFX	Cascade	50 min
Aug 6, 7:13 PM MDT	Severe Thunderstorm Warning	TFX	Lewis and Clark	47 min
Aug 7, 3:52 PM MDT	Severe Thunderstorm Warning	TFX	Chouteau	38 min
Aug 7, 5:31 PM MDT	Severe Thunderstorm Warning	TFX	Fergus	59 min

Nearby

Severe Thunderstorm Warnings in Montana, 2003 Every severe thunderstorm warning in 2003

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.