Alert archive / Montana / Severe Thunderstorm Warnings in 2009

Severe Thunderstorm Warning 68, NWS Great Falls, MT

July 24, 2009Madison County, Montana

NWS Great Falls, MT issued this severe thunderstorm warning at Jul 24, 2009, 3:22 PM MDT for Madison County, Montana. It was in force for 38 min. No storm report in the archive falls inside the area while it was in force.

The area

The counties it named.

The facts

Issued
Jul 24, 2009, 3:22 PM MDT (21:22 UTC)
Expired
Jul 24, 2009, 4:00 PM MDT
In force
38 min
Issued by
NWS Great Falls, MT
Area
Storm-based polygon

County Madison County, MT

The radar

The Great Falls radar (KTFX), 244 km from the middle of the area, began a volume at 21:22 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 12:00Z, 9.4 hours before the alert went out and 261 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 2009-07-24Temperature 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 2009-07-24The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity -70 square meters per square second.19395878Sfc1 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
2156 m above ground
0-6 km bulk shear
32 kt
0-1 km storm-relative helicity
-70 m²/s²
0-3 km storm-relative helicity
102 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

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 24, 2:29 PM MDT, 53 minutes earlier.

Area forecast discussion, Jul 24, 2:29 PM MDT, 53 minutes before
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREAT FALLS MT
229 PM MDT FRI JUL 24 2009

.DISCUSSION...
FRIDAY NIGHT THROUGH SUNDAY...
SHORT TERM FORECAST IS RATHER
UNSETTLED FOR THE NEXT FEW DAYS AS AN UPPER LEVEL LOW TRACKS INTO
NORTH IDAHO AND THEN STALLS OUT OVER THE WEEKEND. THE UPPER LEVEL
DIFFLUENCE ASSOCIATED WITH THIS SYSTEM IS GOING TO BE LOCATED OVER
MONTANA AND SHOULD ALLOW FOR ENHANCED LIFT OF STORMS OVER THE NEXT FEW
DAYS. THERE COULD BE SOME RESIDUAL SHOWERS THAT APPEAR OVERNIGHT
OVER THE NEXT FEW NIGHTS ASSOCIATED WITH THIS UPPER LEVEL SYSTEM.
THE SHOWERS AND THUNDERSTORMS SHOULD REMAIN ISOLATED TO SCATTERED
BUT WILL GENERALLY INITIATE OFF OF THE HIGHER TERRAIN DURING PEAK
HEATING. BY SUNDAY THE LOW WILL START TO MOVE OFF...UNFORTUNATELY
THE MODELS HAVE NOT BEEN IN AGREEMENT AT ALL ABOUT THE TRACK IT
WILL TAKE. HAVE LEFT PRECIP AT CHANCE FOR THIS DUE TO THE
UNCERTAINTY AND WILL MONITOR FOR CHANGES. SUK

SUNDAY NIGHT THROUGH WEDNESDAY NIGHT...MEDIUM RANGE MODELS IN BETTER
AGREEMENT FOR THE START OF THE PERIOD BUT QUICKLY DIVERGE WITH THE
DETAILS. BOTH THE EUROPEAN AND GFS START WITH A CLOSED LOW OVER THE
PACIFIC NORTHWEST AND SCATTERED THUNDERSTORMS OVER THE AREA. THE
CLOSED LOW QUICKLY FILLS AND OPENS INTO AN UPPER TROF MONDAY AND
THEN WEAKENS AS IT MOVES SOUTH. A BUILDING UPPER RIDGE OVER THE
WEST COAST AND A SLOW MOVING CLOSED UPPER LOW OVER EASTERN CANADA
WILL MAINTAIN AN UNSETTLED NORTHWEST FLOW ALOFT OVER THE AREA WITH
ISOLATED TO SCATTERED THUNDERSTORMS EACH DAY. TEMPERATURES WILL BE
NEAR SEASONAL AVERAGES.

THURSDAY AND FRIDAY...MODELS SHOW AN UPPER LEVEL RIDGE OF HIGH
PRESSURE OVER THE PACIFIC NORTHWEST DURING THE PERIOD FOR A MOSTLY
DRY AND WARM WEATHER PATTERN. EXCEPT FOR ISOLATED SHOWERS AND
AFTERNOON THUNDERSTORMS MAINLY OVER THE MOUNTAINS. WILLIAMSON DC
&&

.AVIATION...
UPDATED 1800Z.
A COMPACT UPPER LEVEL LOW PRESSURE SYSTEM CURRENTLY OVER NE WA WILL
DRIFT EAST AND STALL OVER NORTHERN ID DURING THE NEXT 24 HRS. THIS
WILL PROVIDE AN INCREASINGLY MOIST AND UNSTABLE SW FLOW ALOFT WHILE
EASTERLY FLOW REMAINS AT THE SURFACE. EXPECT SHOWERS AND
THUNDERSTORMS TO DEVELOP AND INCREASE IN COVERAGE THROUGH THIS
AFTERNOON WITH GREATEST COVERAGE INITIALLY ALONG THE CONTINENTAL
DIVIDE...SPREADING EAST INTO CENTRAL AND SW MT LATER THIS AFTERNOON
AND EVENING. AREA LEAST IMPACTED WILL BE THE KHVR TERMINAL WHERE
VFR CONDITIONS WILL PERSIST. VFR CONDITIONS WILL ALSO PREVAIL AT
REMAINING TERMINALS...HOWEVER LOCAL MVFR CONDITIONS ARE POSSIBLE
NEAR THUNDERSTORMS.

&&

.FIRE WEATHER...
LOW AFTERNOON HUMIDITIES ARE EXPECTED THROUGH THE WEEKEND...ALONG
WITH A CHANCE FOR THUNDERSTORMS. RIGHT NOW...MOST THUNDERSTORM
ACTIVITY LOOKS TO BE A BIT WET...SO HOPEFULLY ANY LIGHTNING STARTS
WILL BE ABLE TO BE PUT OUT QUICKLY. HOWEVER...ANY LIGHTNING
STRIKES THAT OCCUR WELL AWAY FROM THE PARENT STORM COULD BE A
PROBLEM ALONG WITH ERRATIC GUSTY OUTFLOWS FROM THE STORMS.
ADDITIONALLY SURFACE WINDS WILL BE FAIRLY LIGHT OVER THE NEXT FEW
DAYS...THUS NO FIRE WEATHER WATCH PLANNED FOR AT THIS TIME.

&&

.PRELIMINARY POINT TEMPS/POPS...
GTF  58  91  57  88 /  30  20  20  30
CTB  54  87  54  81 /  40  20  20  30
HLN  60  94  60  91 /  30  20  30  30
BZN  54  95  55  93 /  30  20  30  30
WEY  45  79  46  80 /  20  30  40  50
DLN  54  86  52  84 /  30  20  20  30
HVR  57  96  57  91 /  10  10  10  20
LWT  54  89  55  86 /  20  10  20  30

&&

.TFX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

SHORT TERM...SUK
LONG TERM...HOENISCH
AVIATION...HOENISCH

WEATHER.GOV/GREATFALLS
Hazardous weather outlook, Jul 24, 3:03 PM MDT, 19 minutes before
HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE GREAT FALLS MT
303 PM MDT FRI JUL 24 2009

MTZ008>010-012-014-015-046-048>050-052>055-252115-
BEAVERHEAD-NORTHERN ROCKY MOUNTAIN FRONT-EASTERN GLACIER-CASCADE-
CENTRAL AND SOUTHERN LEWIS AND CLARK-MADISON-EASTERN PONDERA-
SOUTHERN ROCKY MOUNTAIN FRONT-EASTERN TETON-JUDITH BASIN-
JEFFERSON-BROADWATER-MEAGHER-GALLATIN-
303 PM MDT FRI JUL 24 2009

THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF CENTRAL
MONTANA...NORTH CENTRAL MONTANA AND SOUTHWEST MONTANA.

.DAY ONE...THIS AFTERNOON AND TONIGHT

SCATTERED THUNDERSTORMS WILL AFFECT THE REGION THROUGH TODAY. A
FEW STORMS COULD BE STRONG THIS AFTERNOON...WITH THE MAIN THREAT
BEING STRONG WINDS AND HAIL.

.DAYS TWO THROUGH SEVEN...SATURDAY THROUGH THURSDAY

SCATTERED THUNDERSTORMS WILL AFFECT THE REGION THROUGH THE
WEEKEND. A FEW STORMS COULD BE SEVERE SATURDAY AND SUNDAY. THE
MAIN THREAT FROM THE STRONGER STORMS WILL BE DAMAGING WIND GUSTS
AND LARGE HAIL.

.SPOTTER INFORMATION STATEMENT...

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

MTZ011-013-044-045-047-051-252115-
HILL-CHOUTEAU-TOOLE-LIBERTY-BLAINE-FERGUS-
303 PM MDT FRI JUL 24 2009

THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF CENTRAL MONTANA
AND NORTH CENTRAL MONTANA.

.DAY ONE...THIS AFTERNOON AND TONIGHT

A SEVERE THUNDERSTORM WATCH IS IN EFFECT UNTIL 10 PM MDT TONIGHT.
SCATTERED TO NUMEROUS SHOWERS AND THUNDERSTORMS WILL MOVE FROM THE
SOUTHWEST ACROSS MONTANA TO THE NORTH NORTHEAST...THE STRONGEST
STORMS MAY BE CAPABLE OF PRODUCING HAIL UP TO 1 INCH IN DIAMETER
AND WINDS IN EXCESS OF 60 MPH.

.DAYS TWO THROUGH SEVEN...SATURDAY THROUGH THURSDAY

SCATTERED THUNDERSTORMS WILL AFFECT THE REGION THROUGH THE
WEEKEND. A FEW STORMS COULD BE SEVERE SATURDAY AND SUNDAY. THE
MAIN THREAT FROM THE STRONGER STORMS WILL BE DAMAGING WIND GUSTS
AND LARGE HAIL.

.SPOTTER INFORMATION STATEMENT...

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

In the hours before

Special weather statement, Jul 24, 1:57 PM MDT, 1 hour 25 minutes before
SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE GREAT FALLS MT
157 PM MDT FRI JUL 24 2009

MTZ008-015-052-242045-
BEAVERHEAD MT-JEFFERSON MT-MADISON MT-
157 PM MDT FRI JUL 24 2009

...SIGNIFICANT WEATHER ADVISORY FOR NORTHWESTERN MADISON...NORTHERN
BEAVERHEAD AND EXTREME SOUTHERN JEFFERSON COUNTIES UNTIL 245 PM
MDT...

AT 156 PM MDT...NATIONAL WEATHER SERVICE DOPPLER RADAR WAS TRACKING A
STRONG THUNDERSTORM 12 MILES SOUTH OF DIVIDE...OR 25 MILES WEST OF
SHERIDAN...MOVING NORTHEAST AT 15 MPH.

HAIL UP TO ONE-HALF INCH IN DIAMETER AND WIND GUSTS UP TO 50 MPH ARE
EXPECTED WITH THIS STORM...ALONG WITH HEAVY RAIN.

* LOCATIONS IMPACTED INCLUDE...
  RURAL NORTHWESTERN MADISON COUNTY...
  RURAL NORTHERN BEAVERHEAD COUNTY...
  RURAL SOUTHERN JEFFERSON COUNTY...

THIS STORM MAY INTENSIFY...SO BE CERTAIN TO MONITOR LOCAL RADIO AND
TV STATIONS...AS WELL AS LOCAL CABLE TV OUTLETS...FOR ADDITIONAL
INFORMATION AND POSSIBLE WARNINGS FROM THE NATIONAL WEATHER SERVICE.

LAT...LON 4569 11272 4564 11269 4563 11265 4569 11253
      4576 11250 4574 11246 4575 11220 4582 11241
      4574 11209 4546 11269 4560 11286
TIME...MOT...LOC 1957Z 231DEG 11KT 4558 11267
Special weather statement, Jul 24, 2:21 PM MDT, 1 hour 1 minute before
SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE GREAT FALLS MT
221 PM MDT FRI JUL 24 2009

MTZ008-015-242100-
BEAVERHEAD MT-MADISON MT-
221 PM MDT FRI JUL 24 2009

...SIGNIFICANT WEATHER ADVISORY FOR WESTERN MADISON AND CENTRAL
BEAVERHEAD COUNTIES UNTIL 300 PM MDT...

AT 220 PM MDT...NATIONAL WEATHER SERVICE DOPPLER RADAR WAS TRACKING A
STRONG THUNDERSTORM 17 MILES WEST OF DILLON...MOVING EAST AT 35 MPH.

HAIL UP TO ONE-HALF INCH IN DIAMETER AND WIND GUSTS UP TO 50 MPH ARE
EXPECTED WITH THIS STORM...ALONG WITH HEAVY RAIN.

* LOCATIONS IMPACTED INCLUDE...
   DILLON...

THIS STORM MAY INTENSIFY...SO BE CERTAIN TO MONITOR LOCAL RADIO AND
TV STATIONS...AS WELL AS LOCAL CABLE TV OUTLETS...FOR ADDITIONAL
INFORMATION AND POSSIBLE WARNINGS FROM THE NATIONAL WEATHER SERVICE.

LAT...LON 4543 11238 4520 11226 4502 11304 4519 11313
TIME...MOT...LOC 2021Z 248DEG 29KT 4514 11296
Local storm report, Jul 24, 2:56 PM MDT, 26 minutes before
PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE GREAT FALLS MT
256 PM MDT FRI JUL 24 2009

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0254 PM     HAIL             DILLON                  45.22N 112.63W
07/24/2009  E0.50 INCH       BEAVERHEAD         MT   TRAINED SPOTTER

            HEAVY RAIN AND GUSTY WINDS.

&&

SAUCIER
Special weather statement, Jul 24, 3:00 PM MDT, 22 minutes before
SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE GREAT FALLS MT
300 PM MDT FRI JUL 24 2009

MTZ014-052-242145-
CENTRAL AND SOUTHERN LEWIS AND CLARK MT-JEFFERSON MT-
300 PM MDT FRI JUL 24 2009

...SIGNIFICANT WEATHER ADVISORY FOR SOUTHEASTERN LEWIS AND CLARK AND
EXTREME NORTHERN JEFFERSON COUNTIES UNTIL 345 PM MDT...

AT 300 PM MDT...NATIONAL WEATHER SERVICE DOPPLER RADAR WAS TRACKING A
STRONG THUNDERSTORM 6 MILES WEST OF HELENA...MOVING NORTHEAST AT 25
MPH.

HAIL UP TO THE SIZE OF PENNIES AND WIND GUSTS UP TO 50 MPH ARE
EXPECTED WITH THIS STORM...ALONG WITH HEAVY RAIN AND FREQUENT
DANGEROUS LIGHTNING.

LOCATIONS NEAR THE PATH OF THIS STORM INCLUDE...HELENA.

IF THREATENING WEATHER APPROACHES YOUR AREA...TAKE SHELTER IN A
STURDY BUILDING.

LAT...LON 4701 11204 4689 11171 4649 11209 4658 11232
TIME...MOT...LOC 2100Z 208DEG 21KT 4662 11214

MLS
Local storm report, Jul 24, 3:11 PM MDT, 11 minutes before
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Special weather statement, Jul 24, 3:22 PM MDT, 0 minutes before
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The office that day

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

IssuedProductOfficeCountiesLasted
Jul 23, 10:07 PM MDTSpecial Weather StatementTFXTeton38 min
Jul 23, 10:38 PM MDTSpecial Weather StatementTFXLewis and Clark22 min
Jul 24, 1:41 PM MDTSpecial Weather StatementTFXJefferson49 min
Jul 24, 1:57 PM MDTSpecial Weather StatementTFXSilver Bow48 min
Jul 24, 2:21 PM MDTSpecial Weather StatementTFXBeaverhead39 min
Jul 24, 3:00 PM MDTSpecial Weather StatementTFXLewis and Clark45 min
Jul 24, 3:22 PM MDTSpecial Weather StatementTFXMeagher38 min
Jul 24, 3:39 PM MDTSpecial Weather StatementTFXGallatin51 min
Jul 24, 4:02 PM MDTSpecial Weather StatementTFXMeagher43 min
Jul 24, 4:09 PM MDTSpecial Weather StatementTFXGallatin51 min
Jul 24, 4:21 PM MDTSpecial Weather StatementTFXMeagher39 min

Nearby

Severe Thunderstorm Warnings in Montana, 2009Every severe thunderstorm warning in 2009

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.