Alert archive / Montana / Severe Thunderstorm Warnings in 2003

Severe Thunderstorm Warning 99, NWS Great Falls, MT

August 22, 2003Lewis and Clark County, Montana

NWS Great Falls, MT issued this severe thunderstorm warning at Aug 22, 2003, 5:25 PM MDT for Lewis and Clark 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: Aug 22, 2003, 5:25 PM MDT (23:25 UTC)
Expired: Aug 22, 2003, 6:00 PM MDT
In force: 35 min
Issued by: NWS Great Falls, MT
Area: Counties, with a storm outline in the text

County Lewis and Clark County, MT

The radar

The Great Falls radar (KTFX), 96 km from the middle of the area, began a volume at 23:27 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.

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 nearest sounding before it

Great_falls, MT (KTFX), launched 12:00Z, 11.4 hours before the alert went out and 135 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: 4322 m above ground
0-6 km bulk shear: 16 kt
0-1 km storm-relative helicity: -38 m²/s²
0-3 km storm-relative helicity: -15 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.

061 
WUUS55 KTFX 222325 CCA
SVRTFX
MTC049-230000-

BULLETIN - EAS ACTIVATION REQUESTED
SEVERE THUNDERSTORM WARNING...CORRECTED EXPIRATION TIME
NATIONAL WEATHER SERVICE GREAT FALLS MT
515 PM MDT FRI AUG 22 2003

THE NATIONAL WEATHER SERVICE IN GREAT FALLS HAS ISSUED A

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

* UNTIL 600 PM MDT

* AT 512 PM MDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED   
  A SEVERE THUNDERSTORM OVER HELENA...MOVING NORTHEAST AT 30 MPH.

* THE SEVERE THUNDERSTORM WILL BE OVER...
  EAST HELENA AND NORTH HELENA AT 530 PM MDT

WIND GUSTS TO 60 MILES AN HOUR WILL OCCUR WITH THIS STORM.

REPORT SEVERE WEATHER TO THE NEAREST LAW ENFORCEMENT AGENCY. THEY
WILL RELAY YOUR REPORT TO THE NATIONAL WEATHER SERVICE FORECAST
OFFICE IN GREAT FALLS.

LAT...LON 4663 11222 4650 11203 4675 11163 4705 11196

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 22, 2:15 PM MDT, 3 hours 10 minutes earlier.

Area forecast discussion, Aug 22, 2:15 PM MDT, 3 hours 10 minutes before

SOUTHWEST AND NORTH CENTRAL MONTANA FORECAST
NATIONAL WEATHER SERVICE GREAT FALLS MT
215 PM MDT FRI AUG 22 2003

.SHORT TERM...BACKING FLOW ALOFT CONTINUES TO ADVECT MOISTURE OVER
SOUTHWEST MONTANA. DEW POINTS OVER THE AREA ARE IN THE 50S AND
THUNDERSTORMS NOW DEVELOPING WEST OF THE CONTINENTAL DIVIDE AND
APPROACHING YELLOWSTONE PARK. THUNDERSTORMS LIKELY TO MOVE INTO
SOUTHWEST PORTION OF THE COUNTY WARNING AREA LATE THIS AFTERNOON
AND EARLY EVENING. SOME STORMS MAY BECOME STRONG BUT ANY SEVERE
WEATHER LIKELY TO BE ISOLATED. SHORT WAVE MOVES ACROSS AREA LATER
TONIGHT WITH MAIN ENERGY WEST AND NORTH OF GREAT FALLS. STRONG
DOWNSLOPE GRADIENT SETS UP LATER TONIGHT WITH SURFACE WINDS
BECOMING GUSTY. DOWNSLOPE GRADIENT SHOULD INHIBIT PRECIPITATION OVER
THE PLAINS. GRADIENT STAYS RATHER TIGHT SATURDAY WITH WINDS
CONTINUING. A WEAKER SHORT WAVE MOVES ACROSS THE AREA SUNDAY NIGHT
FOR ANOTHER CHANCE OF PRECIPITATION. DRY WESTERLY FLOW FOR MONDAY.
TEMPERATURES WILL REMAIN AT OR SLIGHTLY BELOW SEASONAL AVERAGES.
EMANUEL

.LONG TERM...MONDAY NIGHT THROUGH TUESDAY NIGHT...DRY ZONAL FLOW
ALOFT AND WEAK SURFACE PRESSURE GRADIENT WILL CREATE TRANQUIL
CONDITIONS AND SEASONABLE TEMPERATURES. VERY DRY AIR IN PLACE AND
LACK OF CLOUD COVER WILL ALLOW FOR CHILLY OVERNIGHT LOW TEMPS...
ESPECIALLY IN THE HIGHER VALLEYS. WEDNESDAY THROUGH FRIDAY...MODELS
DISAGREE ON SOLUTION IN THIS TIME FRAME. HAVE MADE ONLY COSMETIC
CHANGES TO GOING FORECAST IN ORDER TO KEEP OUR GRIDS CONSISTENT WITH
NEIGHBORING OFFICES. TREND IS FOR A SLOW WARMING TREND AND A DRY
FORECAST. VILLANI/MPJ

.CCF NUMBERS
GTF BB 058/081 052/083 048 08301
    UUUBB 077/043 077/046 079/052 084/051 075 12000000000
CTB NB 054/077 050/079 047 08300
    BUUBB 072/042 073/044 077/051 079/049 069 02000000000
HLN BB 058/085 054/084 045 08322
    UUUBB 082/043 080/048 083/053 087/052 074 00000000000
BZN BB 054/084 050/084 047 08322
    UUUBB 083/039 078/041 080/053 086/052 077 00000000000
WEY BB 045/078 042/080 039 08422
    UUUBB 078/034 072/037 074/042 079/038 070 00000000000
DLN BB 056/086 053/085 044 08422
    UUUBB 083/041 076/044 080/052 086/051 074 00000000000
HVR BB 060/086 054/084 052 08300
    UUUBB 079/044 078/045 082/054 085/052 077 -3000000000
LWT BB 056/082 053/082 049 08301
    UUUUU 077/042 075/044 077/051 081/051 076 13000000000

.TFX...RED FLAG WARNING FOR ALL FIRE ZONES THROUGH SATURDAY.

Hazardous weather outlook, Aug 22, 6:25 AM MDT, 11 hours before

MTZ008>015-044>055-230010-
HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE GREAT FALLS MT
625 AM MDT FRI AUG 22 2003

THIS HAZARDOUS WEATHER OUTLOOK IS FOR NORTH CENTRAL AND SOUTHWEST MONTANA

.DAY ONE...TODAY

AN UPPER LEVEL DISTURBANCE AND ASSOCIATED COLD FRONT WILL MOVE
THROUGH WESTERN AND CENTRAL MONTANA THIS EVENING. SCATTERED DRY
THUNDERSTORMS WILL DEVELOP AHEAD OF THIS FRONT...PRODUCING STRONG
AND ERRATIC WIND GUSTS AND LIGHTNING STRIKES. HIGHER ELEVATION WINDS
WILL INCREASE THIS AFTERNOON...BECOMING 30 TO 40 MPH BY TONIGHT. AT
THE LOWER ELEVATIONS WINDS WILL INCREASE FROM THE WEST FOLLOWING
FRONTAL PASSAGE. THE GUSTY WINDS AND THUNDERSTORMS...COMBINED WITH
LOW RELATIVE HUMIDITY VALUES AND HIGH FIRE DANGER INDICES HAS
PROMPTED THE ISSUANCE OF RED FLAG WARNINGS ACROSS SOUTHWEST...
CENTRAL AND NORTH CENTRAL MONTANA. PLEASE REFER TO GTFRFWTFX AND
GTFRFWMSO FOR FURTHER INFORMATION.

.DAYS TWO THROUGH SEVEN...SATURDAY THROUGH THURSDAY

A RED FLAG WARNING REMAINS IN EFFECT THROUGH SATURDAY FOR STRONG
WINDS AT THE HIGHER ELEVATIONS ACROSS CENTRAL AND NORTH CENTRAL
MONTANA. PLEASE REFER TO GTFRFWTFX FOR MORE INFORMATION.

ANOTHER UPPER LEVEL DISTURBANCE AND SURFACE COLD FRONT IS EXPECTED
TO MOVE THROUGH CENTRAL MONTANA LATE SUNDAY NIGHT. THIS SYSTEM WILL
BE MONITORED FOR FIRE WEATHER CONCERNS.

.SPOTTER INFORMATION STATEMENT...

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

In the hours before

Local storm report, Aug 22, 5:25 PM MDT, 0 minutes before

LOCAL STORM REPORT
NATIONAL WEATHER SERVICE GREAT FALLS MT
525 PM MDT FRI AUG 22 2003

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

0511 PM    HELENA                    MT   0.75 INCH HAIL
08/22/03   LEWIS  AND  CLARK

0511 PM    HELENA                    MT   58 MPH TSTM GUST
08/22/03   LEWIS  AND  CLARK

NNNN

The office that day

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

Issued	Product	Office	Counties	Lasted
Aug 22, 5:16 PM MDT	Severe Thunderstorm Warning	TFX	Lewis and Clark	44 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; radar from the NEXRAD Level II archive.