Alert archive / Montana / Severe Thunderstorm Warnings in 2013

Severe Thunderstorm Warning 72, NWS Great Falls, MT

July 24, 2013Cascade County, Chouteau County, Montana

NWS Great Falls, MT issued this severe thunderstorm warning at Jul 24, 2013, 8:47 PM MDT for Cascade County, Chouteau County, Montana. It was in force for 43 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, 2013, 8:47 PM MDT (02:47 UTC)
Expired: Jul 24, 2013, 9:30 PM MDT
In force: 43 min
Issued by: NWS Great Falls, MT
Area: Storm-based polygon

Counties Cascade County, MT, Chouteau County, MT

The radar

The Great Falls radar (KTFX), 40 km from the middle of the area, began a volume at 02:49 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 watch it was issued in

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

Issued	Product	Office	Lasted
Jul 24, 5:26 PM MDT	Severe Thunderstorm Watch	SPC	7 hr

The nearest sounding before it

Great_falls, MT (KTFX), launched 00:00Z, 2.8 hours before the alert went out and 26 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: 57 J/kg
Mixed-layer CIN: -63 J/kg
Mixed-layer LCL: 3725 m above ground
0-6 km bulk shear: 34 kt
0-1 km storm-relative helicity: -7 m²/s²
0-3 km storm-relative helicity: 66 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, 6:25 PM MDT, 2 hours 22 minutes earlier.

Area forecast discussion, Jul 24, 6:25 PM MDT, 2 hours 22 minutes before

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREAT FALLS MT
625 PM MDT Wed Jul 24 2013

UPDATED AVIATION SECTION

.DISCUSSION...
Tonight through Friday...The dominant weather feature affecting
the forecast area during the period will be an upper ridge over
the Pacific Northwest which will move to our forecast area Friday.
For tonight a weather disturbance aloft will sweep southeast
through the plains and adjoining mountains. This disturbance is
expected to trigger isolated to scattered thunderstorms by this
evening. Observations early in the afternoon were showing a
moderately unstable airmass near the Canadian border and moderate
wind shear. Will continue to mention a threat of small hail and
gusty winds with the thunderstorms over the northern east slopes
for this evening. On Thursday expect an unstable airmass over most
of the forecast area by the afternoon but do not see any weather
disturbances aloft to speak of. Will continue with the mention of
a slight chance of thunderstorms mainly over the mountains. With
the upper ridge moving over the forecast area on Friday and a
drier airmass expected have dropped the mention of thunderstorms.
Expect a surge of cooler air associated with the weather
disturbance aloft tonight. This will result in lower maximum
temperatures Thursday especially in then north. High temperatures
will rebound Friday with the upper ridge moving over the area.
Blank

Friday night through Wednesday...High pressure aloft will be over
central Montana and the airmass will be warm and, in general, dry.
However, some moisture will have moved into the southwest zones and
the best chance for thunderstorm activity will be in this region
Friday night. To the west, a low pressure trof will be moving over
the West Coast. This will begin a period of slowly falling heights
aloft along with a continued increase of moisture into the region.
The result will be increased afternoon and evening instability and
an increase in thunderstorm activity Saturday. The upper level trof
will be approaching the Rockies by Sunday and the convective
activity will further increase. The approach of the trof will also
cool the airmass and begin a period of slightly cooler temperatures.
Low pressure will remain over British Columbia and the zones will
remain underneath unsettled, southwest flow aloft...and afternoon
and evening convective activity will continue into the new week. By
Tuesday, another low pressure trof will move over the West Coast and
keep the unsettled, southwest flow in place through the end of the
period. Temperatures will remain well above normals through
Saturday. Although the approach of the upper level low pressure trof
will bring some cooler temperatures into the region but temps will
generally remain near or above normals through Wednesday. Zelzer

&&

.AVIATION...
UPDATED 0025Z.
An unstable airmass and a weak surface front moving into the area
has allowed scattered thunderstorms to develop...mainly north of a
KHLN to KBZN line. Some of these storms may become severe.
Convective activity should end by 07z.

&&

.PRELIMINARY POINT TEMPS/POPS...
GTF  55  85  55  90 /  20  10   0  10
CTB  53  81  53  87 /  30  10  10  10
HLN  57  89  58  92 /  10  10  10  10
BZN  51  88  52  89 /  10  10  10  10
WEY  41  80  42  82 /  10  20  20  10
DLN  52  86  52  88 /  10  10  10  10
HVR  54  81  54  85 /  30  10  10  10
LWT  52  79  53  83 /  20  10  10  10

&&

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

weather.gov/greatfalls

Hazardous weather outlook, Jul 24, 6:32 PM MDT, 2 hours 15 minutes before

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE GREAT FALLS MT
632 PM MDT WED JUL 24 2013

MTZ009>014-044>051-260045-
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-
632 PM MDT WED JUL 24 2013

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

.DAY ONE...TONIGHT

A SEVERE THUNDERSTORM WATCH IS IN EFFECT UNTIL 1 AM MDT TONIGHT.

.DAYS TWO THROUGH SEVEN...THURSDAY THROUGH TUESDAY

THE PROBABILITY FOR WIDESPREAD HAZARDOUS WEATHER IS LOW.

.SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION IS REQUESTED FOR REPORTS OF SEVERE WEATHER OR
FLASH FLOODING.

MTZ008-015-052>055-260045-
BEAVERHEAD-MADISON-JEFFERSON-BROADWATER-MEAGHER-GALLATIN-
632 PM MDT WED JUL 24 2013

THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF SOUTHWEST
MONTANA.

.DAY ONE...TONIGHT

THE PROBABILITY FOR WIDESPREAD HAZARDOUS WEATHER IS LOW.

.DAYS TWO THROUGH SEVEN...THURSDAY THROUGH TUESDAY

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, Jul 24, 7:50 PM MDT, 57 minutes before

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE GREAT FALLS MT
750 PM MDT WED JUL 24 2013

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

0742 PM     HAIL             7 SSW CONRAD            48.08N 112.00W
07/24/2013  E0.50 INCH       PONDERA            MT   PUBLIC

0742 PM     TSTM WND GST     7 SSW CONRAD            48.08N 112.00W
07/24/2013  M73 MPH          PONDERA            MT   PUBLIC

&&

JNS

Local storm report, Jul 24, 8:06 PM MDT, 41 minutes before

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE GREAT FALLS MT
806 PM MDT WED JUL 24 2013

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

0740 PM     HAIL             4 NW BRADY              48.08N 111.90W
07/24/2013  E0.75 INCH       PONDERA            MT   TRAINED SPOTTER

&&

EMANUEL

Local storm report, Jul 24, 8:13 PM MDT, 34 minutes before

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE GREAT FALLS MT
813 PM MDT WED JUL 24 2013

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

0808 PM     HAIL             1 NE DUTTON             47.86N 111.70W
07/24/2013  E1.00 INCH       TETON              MT   TRAINED SPOTTER

            30 - 40 MPH WINDS

&&

EMANUEL

Local storm report, Jul 24, 8:23 PM MDT, 24 minutes before

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE GREAT FALLS MT
823 PM MDT WED JUL 24 2013

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

0620 PM     HAIL             1 W CUT BANK            48.63N 112.33W
07/24/2013  E1.00 INCH       GLACIER            MT   TRAINED SPOTTER

&&

EMANUEL

Local storm report, Jul 24, 8:31 PM MDT, 16 minutes before

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE GREAT FALLS MT
831 PM MDT WED JUL 24 2013

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

0800 PM     HAIL             3 NE DUTTON             47.88N 111.67W
07/24/2013  E1.00 INCH       TETON              MT   TRAINED SPOTTER

&&

EMANUEL

Local storm report, Jul 24, 8:42 PM MDT, 5 minutes before

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE GREAT FALLS MT
842 PM MDT WED JUL 24 2013

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

0820 PM     HAIL             24 NW GREAT FALLS       47.75N 111.66W
07/24/2013  M1.25 INCH       TETON              MT   TRAINED SPOTTER

            BENTON LAKE AREA

&&

EMANUEL

The office that day

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

Issued	Product	Office	Counties	Lasted
Jul 24, 6:05 PM MDT	Severe Thunderstorm Warning	TFX	Glacier, Pondera	40 min
Jul 24, 6:09 PM MDT	Severe Thunderstorm Warning	TFX	Glacier	51 min
Jul 24, 6:38 PM MDT	Severe Thunderstorm Warning	TFX	Glacier, Pondera	52 min
Jul 24, 7:17 PM MDT	Severe Thunderstorm Warning	TFX	Pondera, Teton, Toole	43 min
Jul 24, 7:55 PM MDT	Severe Thunderstorm Warning	TFX	Cascade, Chouteau, Pondera, Teton	65 min
Jul 24, 9:22 PM MDT	Severe Thunderstorm Warning	TFX	Cascade, Chouteau, Judith Basin	53 min
Jul 24, 10:07 PM MDT	Severe Thunderstorm Warning	TFX	Cascade, Judith Basin	38 min
Jul 24, 10:39 PM MDT	Special Weather Statement	TFX	Judith Basin	66 min
Jul 25, 2:46 PM MDT	Fire Weather Watch	TFX	Broadwater, Gallatin, Glacier, Jefferson, Lewis and Clark, Liberty and 4 more	39 hr

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.