Alert archive / Montana / Severe Thunderstorm Warnings in 2013

Severe Thunderstorm Warning 99, NWS Great Falls, MT

August 5, 2013Glacier County, Toole County, Montana

NWS Great Falls, MT issued this severe thunderstorm warning at Aug 5, 2013, 3:18 PM MDT for Glacier County, Toole County, Montana. It was in force for 42 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: Aug 5, 2013, 3:18 PM MDT (21:18 UTC)
Expired: Aug 5, 2013, 4:00 PM MDT
In force: 42 min
Issued by: NWS Great Falls, MT
Area: Storm-based polygon

Counties Glacier County, MT, Toole County, MT

The radar

The Great Falls radar (KTFX), 153 km from the middle of the area, began a volume at 21:17 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, 9.3 hours before the alert went out and 188 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: 1833 m above ground
0-6 km bulk shear: 31 kt
0-1 km storm-relative helicity: 76 m²/s²
0-3 km storm-relative helicity: 97 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 Aug 5, 2:59 PM MDT, 19 minutes earlier.

Area forecast discussion, Aug 5, 2:59 PM MDT, 19 minutes before

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREAT FALLS MT
259 PM MDT Mon Aug 5 2013

.DISCUSSION...

This afternoon through Wednesday...Scattered thunderstorms have
developed this afternoon across north central and southwest
Montana ahead of a shortwave trough moving southeast out of
Alberta. A weak cold front has also moved south into north central
Montana, providing a focus for thunderstorm development. Moderate
to strong wind shear with moderate to high precipitable water has
caused many of the storms across north central Montana to become
strong with small hail, brief heavy rainfall, and gusty winds. A
few of these storms have even become severe with large hail. The
convective activity extends north only into far southern Alberta,
so am expecting the activity to generally decrease after 6 pm MDT,
with the threat for small hail, heavy rain, and gusty winds
continuing into the early evening hours. The primary additional
threat will be the potential for localized flooding from the brief
heavy rainfall. Will continue to monitor this situation for
possible flood highlights. Thunderstorms will likely diminish
before midnight as the shortwave trough moves into the area
overnight. An upper level ridge of high pressure will then begin
to build back into the area for Tuesday through Wednesday, for a
more anticyclonic northwesterly flow aloft. A few weak
disturbances will move through this flow through the period, for
at least a slight chance of showers/thunderstorms across north
central Montana, mainly during the afternoon/evening hours. The
airmass should remain dry enough to prevent storm development
across southwest Montana. Temperatures will remain about 5 degrees
below seasonal averages through Tuesday, but the rebuilding ridge
will help warm temperatures closer to normal into Wednesday.
Coulston

Wednesday night through Monday...A slightly unstable summer like
weather pattern will continue to reside over the region for the
second half of the work week and into next weekend. Again tonight
both the GFS/EC models differ in the exact timing/placement with
the upper level disturbances moving through the region. Thus
isolated thunderstorms look possible most days from Thursday
through Monday. However...there looks to be just enough model
support to try and keep the lower elevations drier from Wednesday
night through Thursday night...thus pops have been lowered just a
touch for many lower elevation locations. Otherwise...isolated to
scattered thunderstorms are expected across the region later this
week...through the weekend...and into early next week. In terms of
temperatures...summer like temperatures will continue through the
period...with afternoon highs near normal most days. The only
change was to lower the afternoon highs a touch for next
weekend...especially in southwest MT...as the latest forecast
models indicate afternoon highs in southwest MT should now
generally be in the upper 80s rather than near or just above 90
degrees. Brusda

&&

.AVIATION...
UPDATED 1755Z.
An upper-level trough and accompanying plume of Pacific moisture
will move along the US/Can border today, sparking scattered
thunderstorms across central and southwest MT this afternoon/
evening. A weak surface cold front from this system is currently
near KCTB and should only make slow southward progress through 00Z.
There is potential for isolated stronger storms near/along the
front, mainly vcnty KCTB/KHVR, but could come as far south as KGTF
by late aftn. Main threat would be gusty outflow winds and brief
heavy rainfall. Expect VFR conditions for the most part, though
brief MVFR is possible near any stronger storms. Convective activity
will dissipate this evening with gradually decreasing cloud cover.
Waranauskas

&&

.PRELIMINARY POINT TEMPS/POPS...
GTF  51  80  54  85 /  40  10  10  10
CTB  48  77  53  79 /  30  10  10  20
HLN  55  84  57  87 /  40  10  10  10
BZN  49  82  49  85 /  20  10  10  10
WEY  33  76  36  78 /  10  10   0  10
DLN  48  82  49  84 /  20  10  10  10
HVR  53  78  54  80 /  40  20  10  30
LWT  50  75  51  81 /  50  20  10  20

&&

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

SHORT TERM...COULSTON
LONG TERM...BRUSDA
AVIATION...WARANAUSKAS

weather.gov/greatfalls

Hazardous weather outlook, Aug 5, 4:16 AM MDT, 11 hours 2 minutes before

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE GREAT FALLS MT
416 AM MDT MON AUG 5 2013

MTZ009>014-044>051-054-061030-
NORTHERN ROCKY MOUNTAIN FRONT-EASTERN GLACIER-HILL-CASCADE-
CHOUTEAU-CENTRAL AND SOUTHERN LEWIS AND CLARK-TOOLE-LIBERTY-
EASTERN PONDERA-BLAINE-SOUTHERN ROCKY MOUNTAIN FRONT-
EASTERN TETON-JUDITH BASIN-FERGUS-MEAGHER-
416 AM MDT MON AUG 5 2013

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

.DAY ONE...TODAY AND TONIGHT

SCATTERED SHOWERS AND THUNDERSTORMS ARE EXPECTED ACROSS MUCH OF
NORTH CENTRAL AND CENTRAL MONTANA THIS AFTERNOON AND EVENING. A
FEW OF THE THUNDERSTORMS WILL HAVE BRIEF HEAVY RAINFALL...GUSTY
WINDS TO 40 MPH AND SMALL HAIL.

.DAYS TWO THROUGH SEVEN...TUESDAY THROUGH SUNDAY

THE PROBABILITY FOR WIDESPREAD HAZARDOUS WEATHER IS LOW.

.SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION IS NOT EXPECTED AT THIS TIME.

MTZ008-015-052-053-055-061030-
BEAVERHEAD-MADISON-JEFFERSON-BROADWATER-GALLATIN-
416 AM MDT MON AUG 5 2013

THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF SOUTHWEST
MONTANA.

.DAY ONE...TODAY AND TONIGHT

THE PROBABILITY FOR WIDESPREAD HAZARDOUS WEATHER IS LOW.

.DAYS TWO THROUGH SEVEN...TUESDAY THROUGH SUNDAY

THE PROBABILITY FOR WIDESPREAD HAZARDOUS WEATHER IS LOW.

.SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION IS NOT EXPECTED AT THIS TIME.

In the hours before

Local storm report, Aug 5, 2:16 PM MDT, 1 hour 2 minutes before

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE GREAT FALLS MT
216 PM MDT MON AUG 05 2013

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

0210 PM     HAIL             SHELBY                  48.51N 111.86W
08/05/2013  E0.25 INCH       TOOLE              MT   LAW ENFORCEMENT

            SMALL HAIL AND BREIF HEAVY RAINFALL IN SHELBY

&&

HOENISCH

Special weather statement, Aug 5, 2:25 PM MDT, 53 minutes before

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE GREAT FALLS MT
225 PM MDT MON AUG 5 2013

MTZ013-044>046-049-052130-
CHOUTEAU MT-EASTERN PONDERA MT-EASTERN TETON MT-LIBERTY MT-TOOLE MT-
225 PM MDT MON AUG 5 2013

...SIGNIFICANT WEATHER ADVISORY FOR EASTERN PONDERA...EXTREME
NORTHEASTERN TETON...SOUTHEASTERN TOOLE...SOUTHERN LIBERTY AND
NORTHWESTERN CHOUTEAU COUNTIES UNTIL 330 PM MDT...

AT 220 PM MDT...NATIONAL WEATHER SERVICE DOPPLER RADAR WAS TRACKING A
STRONG THUNDERSTORM 14 MILES SOUTHEAST OF SHELBY...MOVING EAST AT 25
MPH. ADDITIONAL STRONG THUNDERSTORMS WERE DEVELOPING OVER NORTHWEST
CHOUTEAU COUNTY.

HAIL UP TO THE SIZE OF NICKELS AND WIND GUSTS UP TO 40 MPH ARE
EXPECTED WITH THESE STORMS...ALONG WITH HEAVY RAIN.

* LOCATIONS IMPACTED INCLUDE...
   DEVON...
   GALATA...
   LOTHAIR...

THESE STORMS 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 4860 11078 4853 11075 4822 11075 4822 11064
      4824 11062 4785 11045 4800 11161 4823 11191
      4857 11171
TIME...MOT...LOC 2023Z 286DEG 23KT 4836 11163

Special weather statement, Aug 5, 2:36 PM MDT, 42 minutes before

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE GREAT FALLS MT
236 PM MDT MON AUG 5 2013

MTZ011-052115-
HILL MT-
236 PM MDT MON AUG 5 2013

...SIGNIFICANT WEATHER ADVISORY FOR EASTERN HILL COUNTY UNTIL 315 PM
MDT...

AT 230 PM MDT...NATIONAL WEATHER SERVICE DOPPLER RADAR WAS TRACKING A
STRONG THUNDERSTORM 14 MILES EAST OF GILDFORD...OR 15 MILES WEST OF
HAVRE...MOVING EAST AT 25 MPH.

WIND GUSTS UP TO 40 MPH ARE EXPECTED WITH THIS STORM...ALONG WITH
HEAVY RAIN.

* LOCATIONS IMPACTED INCLUDE...
   HAVRE...

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 4866 10952 4840 10960 4857 11014 4869 11006
TIME...MOT...LOC 2036Z 286DEG 21KT 4860 10995

WARANAUSKAS

Local storm report, Aug 5, 2:47 PM MDT, 31 minutes before

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE GREAT FALLS MT
247 PM MDT MON AUG 05 2013

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

0240 PM     HAIL             11 S DEVON              48.30N 111.52W
08/05/2013  M1.00 INCH       TOOLE              MT   TRAINED SPOTTER

&&

HOENISCH

Local storm report, Aug 5, 3:02 PM MDT, 16 minutes before

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE GREAT FALLS MT
302 PM MDT MON AUG 05 2013

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

0301 PM     HAIL             HAVRE                   48.54N 109.68W
08/05/2013  E0.25 INCH       HILL               MT   PUBLIC

            PEA SIZE HAIL COVERING THE GROUND IN HAVRE. BREIF HEAVY
            RAIN OBSERVED AS WELL. STORM IS PASSING.

&&

HOENISCH

Local storm report, Aug 5, 3:08 PM MDT, 10 minutes before

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE GREAT FALLS MT
308 PM MDT MON AUG 05 2013

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

0302 PM     HAIL             HAVRE                   48.55N 109.68W
08/05/2013  M1.00 INCH       HILL               MT   TRAINED SPOTTER

            HAIL RANGING FROM PEA TO QUARTER SIZED.

&&

HOENISCH

The office that day

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

Issued	Product	Office	Counties	Lasted
Aug 5, 1:17 PM MDT	Special Weather Statement	TFX	Toole	43 min
Aug 5, 1:34 PM MDT	Severe Thunderstorm Warning	TFX	Glacier, Pondera, Toole	41 min
Aug 5, 2:25 PM MDT	Special Weather Statement	TFX	Liberty	65 min
Aug 5, 2:36 PM MDT	Special Weather Statement	TFX	Hill	39 min
Aug 5, 2:45 PM MDT	Severe Thunderstorm Warning	TFX	Chouteau, Liberty, Toole	60 min
Aug 5, 3:20 PM MDT	Severe Thunderstorm Warning	TFX	Chouteau	55 min
Aug 5, 3:55 PM MDT	Severe Thunderstorm Warning	TFX	Toole	50 min
Aug 5, 4:09 PM MDT	Special Weather Statement	TFX	Toole	51 min
Aug 5, 4:18 PM MDT	Special Weather Statement	TFX		42 min
Aug 5, 4:28 PM MDT	Special Weather Statement	TFX	Broadwater	47 min
Aug 5, 4:30 PM MDT	Special Weather Statement	TFX	Gallatin	45 min
Aug 5, 4:41 PM MDT	Special Weather Statement	TFX	Liberty	49 min
Aug 5, 5:18 PM MDT	Severe Thunderstorm Warning	TFX	Blaine, Chouteau, Hill	57 min

Nearby

Severe Thunderstorm Warnings in Montana, 2013 Every severe thunderstorm warning in 2013

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.