Hail in Montana, July 9, 2022

Area Forecast Discussion
National Weather Service Missoula MT
138 PM MDT Sat Jul 9 2022

...A Few Severe Thunderstorms Possible Today...

.DISCUSSION...Satellite loops are showing a ridge of high
pressure re-amplifying as the next shortwave disturbance
approaches the region. Altocumulus clouds are moving into the
region ahead of the shortwave disturbance, which shows a
precursor of storms today. Ingredients for thunderstorms are now
looking quite similar to Friday’s. High surface dew points, warm
temperatures, abundant convective available potential energy, and
deep shear will again cause strong thunderstorms to develop this
afternoon. The Storm Prediction Center has much of the area with a
5 percent probability of severe thunderstorms (1 inch hail or
greater and/or 60 mph+ winds), and a 15 percent probability in
west- central Montana and eastward. If you are going to be
outdoors this afternoon and evening, make sure to have a plan to
quickly go indoors or go to a safe place. Yesterday we had
reports of 2.5 inch hail out of severe storms, and with conditions
being similar today, it certainly possible to see large, damaging
hail again.

Sunday has a much more stable profile with most of the area
expected to be dry and a little cooler than today. Convection
allowing models show isolated showers in Glacier National Park
and near Butte which generally look weak.

High pressure has been consistently showing up in model guidance for
Monday with warm and dry conditions expected.

Model clusters reveal southwesterly flow developing to our west,
causing hot temperatures in north-central Idaho and western
Montana. A plume of monsoon moisture is now showing up for Tuesday
night so a slight chance for storms has been added to the
forecast.

The chance for monsoonal moisture and thunderstorms increases
over the region by the middle and end of next week.

&&

.AVIATION...Showers and thunderstorms continue as the primary concern
this afternoon and evening with the majority developing between
09/21z and 10/03z. Latest model guidance would suggest that the
strongest storms would primarily be found from Idaho County, Idaho
east and north over much of west-central Montana. The primary
threat would be up to two inch size hail, then strong gusty
winds, lightning and brief heavy rain. Be advised that large hail
was observed yesterday a couple of miles away from the main
reflectivity cores. Storm motion will generally be to the
northeast between 25 and 35 knots, but a few stronger storms may
present more of a deviant motion to the east-northeast. Showers
and thunderstorms will diminish in the late evening. Lastly, watch
for patchy morning fog in the valleys where considerable rain
fell yesterday.

&&

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

Special Weather Statement
National Weather Service Missoula MT
225 PM MDT Sat Jul 9 2022

IDZ006-MTZ005-006-092100-
Southern Clearwater Mountains ID-Bitterroot/Sapphire Mountains MT-
Missoula/Bitterroot Valleys MT-
225 PM MDT Sat Jul 9 2022

...A strong thunderstorm will impact portions of east central Idaho
and west central Ravalli Counties through 300 PM MDT/200 PM PDT/...

At 224 PM MDT/124 PM PDT/, Doppler radar was tracking a strong
thunderstorm 22 miles southwest of Conner, or 36 miles southwest of
Hamilton, moving northeast at 40 mph.

HAZARD...Winds in excess of 30 mph and half-inch size hail.

SOURCE...Radar indicated.

IMPACT...Gusty winds could knock down tree limbs and blow around
         unsecured objects. Minor damage to outdoor objects is
         possible.

This storm will remain over mainly rural areas of east central Idaho
and west central Ravalli Counties.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

This storm may intensify, so be certain to monitor local radio
stations and available television stations for additional information
and possible warnings from the National Weather Service.

&&

LAT...LON 4566 11451 4578 11471 4614 11450 4591 11410
TIME...MOT...LOC 2024Z 218DEG 37KT 4579 11455

MAX HAIL SIZE...0.50 IN
MAX WIND GUST...30 MPH