Special Weather Statement, NWS Great Falls, MT

Area Forecast Discussion
National Weather Service Great Falls MT
1012 AM MDT Wed Aug 4 2021

.SYNOPSIS...

Hot, mostly dry and breezy weather returns today and Thursday.
Isolated to possibly scattered showers and thunderstorms are
possible during the afternoon and evening hours, but most storms
are expected to have little in the way of rain and will likely
generate gusty and erratic winds. A slow cooling trend with a
chance of precipitation is anticipated for Friday into early next
week.

&&

.UPDATE...

Smoky, hazy skies continue this morning across North-Central and
Southwestern Montana. A few showers and thunderstorms remain
possible this afternoon, with some of the showers possibly
producing some gusty winds. Ludwig

&&

.AVIATION...
555 AM MDT Wed Aug 4 2021 (04/12Z TAF period)

High pressure ridging aloft will keep the region mostly dry through
early afternooon with widespread haze and areas of smoke expected
to persist into Thursday. While VFR conditions are expected to
prevail through the forecast period, MVFR visibility can be expected
at times.  Disturbance aloft pushes into the western edge of the
ridge this afternoon and evening for isolated showers and
thunderstorms producing erratic and gusty winds. Periods of mountain
obscuration are expected throughout the TAF period. mpj

Refer to weather.gov/zlc for more detailed regional aviation weather
and hazard information.

&&

.PREV DISCUSSION...
/ISSUED 555 AM MDT Wed Aug 4 2021/

Upper level high pressure builds over the region for a return to
hot, breezy, and mostly dry conditions today and Thursday.
However, isolated showers and possibly a thunderstorm or two are
anticipated this afternoon and evening with most storms bringing
only light rainfall amounts along with gusty and erratic outflow
winds. Thursday and Friday will see a shortwave trough approach
Montana from the southwest with the upper level ridge being pushed
eastward for an increasing chance of showers and thunderstorms
across southwestern and southern portions of central Montana.
Monsoonal moisture caught up in this system will bring a risk for
locally heavy rains to this region where WPC has issued a slight
risk for excessive rainfall Additionally, far western portions of
southwestern Montana have been placed in SPC's Marginal Risk
category for severe thunderstorms on Thursday. Unsettled
conditions will continue to affect the southern half of NWS Great
Fall's forecast area (generally south of a line from Helena to
Lewistown) Thursday night and Friday as the system progresses
eastward through the region.

Ensemble guidance supports weak upper level troughing over the
Pacific Northwest and Northern Rocky Mountains through the
weekend and into early next week. Additionally, there is a good
chance for a cold front to push through the state on Saturday.
At this time, this front is expected to bring only a slight chance
for showers, but will instead bring moderately strong west to
northwest winds for an increased risk of fire weather concerns. A
stronger upper level wave swings across the state Sunday and
Monday for a better chance of precipitation and (believe it or
not) a good chance for temperatures that will be below seasonal
averages. Unsettled conditions could persist through Wednesday of
next week, but confidence is currently low due to differences in
long range ensemble guidance. mpj

&&

.PRELIMINARY POINT TEMPS/POPS...
GTF  93  55  92  60 /  20  20  10  30
CTB  90  52  90  59 /  30  20  10  20
HLN  94  57  93  58 /  20  10  30  50
BZN  90  53  91  54 /  20  10  20  50
WYS  81  43  82  44 /  30  10  30  60
DLN  88  52  86  53 /  20  10  40  70
HVR  93  58  93  61 /  20  20   0  20
LWT  89  55  90  59 /  20  20  10  30

&&

.TFX WATCHES/WARNINGS/ADVISORIES...
None.
&&

http://www.weather.gov/greatfalls

Special Weather Statement
National Weather Service Great Falls MT
303 PM MDT Wed Aug 4 2021

MTZ010-042145-
Eastern Glacier MT-
303 PM MDT Wed Aug 4 2021

...A strong thunderstorm will impact portions of northeastern Glacier
County through 345 PM MDT...

At 303 PM MDT, Doppler radar was tracking a strong thunderstorm 25
miles north of North Browning, or 28 miles northwest of Cut Bank,
moving northeast at 30 mph.

HAZARD...Winds in excess of 30 mph and half inch 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 northeastern
Glacier County.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

If outdoors, consider seeking shelter inside a building.

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 4894 11230 4880 11282 4894 11295 4900 11282
      4900 11236
TIME...MOT...LOC 2103Z 242DEG 24KT 4891 11280

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

CMC