Alert archive / Montana / Severe Thunderstorm Warnings in 2022

Severe Thunderstorm Warning 12, NWS Missoula, MT

July 7, 2022Powell County, Montana

NWS Missoula, MT issued this severe thunderstorm warning at Jul 7, 2022, 5:55 PM MDT for Powell County, Montana. It was in force for 20 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 7, 2022, 5:55 PM MDT (23:55 UTC)
Expired: Jul 7, 2022, 6:15 PM MDT
In force: 20 min
Issued by: NWS Missoula, MT
Area: Storm-based polygon
Hail: 1.0 in
Wind: 50.0 mph

County Powell County, MT

The radar

The Missoula radar (KMSX), 82 km from the middle of the area, began a volume at 23:55 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.

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 Missoula, MT wrote its last area forecast discussion before this severe thunderstorm warning went out at Jul 7, 1:08 PM MDT, 4 hours 47 minutes earlier.

Area forecast discussion, Jul 7, 1:08 PM MDT, 4 hours 47 minutes before

Area Forecast Discussion
National Weather Service Missoula MT
108 PM MDT Thu Jul 7 2022

.DISCUSSION...Thunderstorms are in the forecast again today and
tomorrow. The combination of clear skies, a moist air mass, and
southwest flow are the standard ingredients for thunderstorms in
the Northern Rockies, and we have plenty of all of them. Generally,
we expect heavy rain with thunderstorms, but there is a slight
chance that some storms will be severe and produce 1 inch or
larger hail and/or winds 60 mph or more. The severe storm
potential this evening will remain greatest in southwest Montana,
namely Silver Bow county. Central Idaho and the rest of western
Montana can expect heavy rain with thunderstorms, which is a minor
downgrade in the expected intensity of storms compared to
previous forecasts.

Flash flooding is always a concern with thunderstorms with heavy
rain. For this evening, the storms are expected to be moving at
20-35 mph depending on location. This speed will keep them from
lingering too long in one place, which reduces the chances for a
flash flood. However, if storms start "training", which is
when they form one behind the other, then any location that gets
hit multiple times may still see some flash flooding. That is the
main threat we'll be watching for this evening. For Friday, the
thunderstorm situation looks very similar.

For the longer term forecast, the sub-tropical ridge over the
southwest is growing stronger. Early next week, a transitory ridge
will move across the Northern Rockies and become superimposed on
the high pressure centered over the Four Corners region of the US.
This will cause the warmest temperatures of the year so far, with
the best potential for western Montana locations to reach the
100F mark. Ensemble models agree very well on this, so forecast
confidence is high. Some moisture from the Desert Southwest
monsoon may work its way north and cause some thunderstorms over
southwest Montana next week.

But alas, the ridge is only transitory over our region, and
ensembles agree on it breaking down mid to late next week with a
return southwest flow. Naturally, this will bring back the
chances of thunderstorms.

&&

.AVIATION...Showers and thunderstorms are beginning to develop
across portions of Lemhi county and southwest Montana this
afternoon. The convection is anticipated to increase in coverage
and intensity across north central Idaho into west central and
southwest Montana during the remainder of the afternoon and
evening. KBTM and KSMN have the best chance of being impacted by a
thunderstorm until 08/02z. These storms will be capable of
producing heavy rain, hail, and gusty erratic winds. The models
are indicating that KMSO could be impacted by storms between
08/00z to 08/08z. Nocturnal convection appears to linger across
southern Lemhi county. Any places that receive some rain this
afternoon and evening have the potential of developing patchy fog
by Friday morning.

&&

.MSO WATCHES/WARNINGS/ADVISORIES...
MT...None.
ID...None.
&&

In the hours before

Special weather statement, Jul 7, 2:55 PM MDT, 3 hours before

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Special weather statement, Jul 7, 4:10 PM MDT, 1 hour 45 minutes before

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Local storm report, Jul 7, 5:04 PM MDT, 51 minutes before

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Special weather statement, Jul 7, 5:14 PM MDT, 41 minutes before

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Special weather statement, Jul 7, 5:26 PM MDT, 29 minutes before

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Local storm report, Jul 7, 5:28 PM MDT, 27 minutes before

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE MISSOULA MT
528 PM MDT THU JUL 7 2022

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

0528 PM     HAIL             DEER LODGE              46.39N 112.74W
07/07/2022  M0.50 INCH       POWELL             MT   TRAINED SPOTTER

            PEA SIZE TO HALF INCH HAIL. HEAVY RAIN
            ONGOING.

&&

AL

The office that day

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

Issued	Product	Office	Counties	Lasted
Jul 6, 6:11 PM MDT	Special Weather Statement	MSO		34 min
Jul 6, 6:19 PM MDT	Special Weather Statement	MSO	Missoula	26 min
Jul 6, 8:51 PM MDT	Special Weather Statement	MSO	Sanders	24 min
Jul 6, 9:06 PM MDT	Special Weather Statement	MSO	Sanders	24 min
Jul 6, 9:25 PM MDT	Special Weather Statement	MSO	Sanders	35 min
Jul 6, 10:05 PM MDT	Special Weather Statement	MSO	Lincoln	40 min
Jul 7, 6:58 AM MDT	Special Weather Statement	MSO	Sanders	47 min
Jul 7, 8:20 AM MDT	Special Weather Statement	MSO	Sanders	25 min
Jul 7, 2:52 PM MDT	Special Weather Statement	MSO		38 min
Jul 7, 4:10 PM MDT	Special Weather Statement	MSO	Silver Bow	35 min
Jul 7, 5:14 PM MDT	Special Weather Statement	MSO	Missoula	31 min
Jul 7, 5:26 PM MDT	Special Weather Statement	MSO	Powell	49 min
Jul 6, 7:25 PM MDT	Severe Thunderstorm Warning Considerable damage threat	MSO	Idaho	35 min
Jul 6, 7:52 PM MDT	Severe Thunderstorm Warning Considerable damage threat	MSO	Idaho	23 min
Jul 6, 10:19 PM MDT	Special Weather Statement	MSO	Lewis	41 min
Jul 7, 2:08 PM MDT	Special Weather Statement	MSO	Lemhi	37 min
Jul 7, 2:55 PM MDT	Special Weather Statement	MSO	Lemhi	35 min
Jul 7, 3:14 PM MDT	Areal Flood Advisory	MSO	Lemhi	107 min

Nearby

Severe Thunderstorm Warnings in Montana, 2022 Every severe thunderstorm warning in 2022

Sources

The product and its follow-ups from the Iowa Environmental Mesonet's archive of National Weather Service and Storm Prediction Center text; radar from the NEXRAD Level II archive.