Special Weather Statement, NWS Missoula, MT

Area Forecast Discussion National Weather Service Missoula MT 319 AM
MST Fri Feb 26 2021

.DISCUSSION...Regional radar and satellite analysis depict the
next surge of Pacific moisture has moved onshore into western Oregon
and Washington early this morning. Widespread snowfall is expected
by the morning commute across north central Idaho as this surge of
moisture moves across eastern Washington. High confidence exists for
a period of heavy snowfall across the Clearwater Mountains this
morning through the late afternoon hours, where a winter storm
warning remains in effect. Forecast soundings and cross- sections
depict a favorable scenario for snowfall rates exceeding one inch
per hour, particularly across mountain locales in Idaho County.

A shortwave trough and associated surface cold front will push
across western Montana by the early afternoon. Modest confidence
exists for a period of accumulating snowfall across the Camas
Prairie Friday afternoon as the upper level flow becomes
northwesterly. High resolution model guidance continues to advertise
the potential for intense snow showers along and south of the I-90
corridor in western Montana this afternoon and early evening. Given
relatively warm surface temperatures and a late February sun angle,
road impacts will be highly variable. Nonetheless, the afternoon
commute will likely be impacted by these snow showers. Model
guidance has trended higher on snowfall accumulations this afternoon
and early evening across the Missoula and Bitterroot valleys,
suggesting a 50/50 chance for 2 inches or more of snowfall by late
this evening. Further winter weather highlights may be warranted for
the Bitterroot and Missoula valley as these showers begin to come
together. Snow shower activity will gradually retreat to the higher
terrain Friday night into Saturday morning.

A relatively unstable northwesterly flow will promote snow shower
activity Saturday across the Northern Rockies. Periodic visibility
reductions will be the primary impact to valley locations, with
little to any accumulation expected. The Clearwater, Bitterroot, and
Mission mountains will continue to see accumulating snow, albeit,
light amounts.

A drying and warming trend is expected Sunday and Monday as high
pressure builds across the Northern Rockies. Model guidance
continues to struggle with the evolution of the weather pattern
Tuesday through Thursday this upcoming week. Guidance does agree
with a splitting upper trough approaching the Pacific Northwest
coastline Monday. Model solutions quickly diverge as this system
approaches the Northern Rockies. The bottom line is temperatures
will remain near seasonal averages with highs in the upper 30s to
low 40s across valley locations. Periods of light to moderate
mountain snowfall are possible during this period, particularly
along the Idaho and Montana border. /Lukinbeal

&&

.AVIATION...High confidence exists for widespread snowfall
across north central Idaho through 27/0000Z as a Pacific storm
system moves into the area. Periodic reductions in visibility will
continue across west central Montana this morning as snow showers
traverse across the Clearwater and Bitterroot Mountains. Convective
snow showers and bands will develop for areas along and south of the
I-90 corridor in western Montana this afternoon. Sudden visibility
reductions will be common as snow showers will be capable of
producing snowfall rates of up to one inch per hour.
Brief IFR to LIFR visibility reductions are possible at KMSO from
26/1800z to 27/0300z. Snow shower activity will gradually diminish
following 27/0600z, with the majority of accumulating snow being
confined the higher terrain. /Lukinbeal

&&

.MSO WATCHES/WARNINGS/ADVISORIES...
MT...     Winter Weather Advisory until 8 AM MST this morning West
Glacier      Region.

     Winter Weather Advisory until 8 AM MST this morning
     Kootenai/Cabinet Region.

     Winter Weather Advisory until 5 PM MST this afternoon
     Bitterroot/Sapphire Mountains.

     Winter Weather Advisory until 5 PM MST this afternoon
     Potomac/Seeley Lake Region.

     Winter Weather Advisory until 5 PM MST this afternoon Lower
     Clark Fork Region.

ID...Winter Weather Advisory until 4 PM PST this afternoon Lower
     Hells Canyon/Salmon River Region.

     Winter Storm Warning until 4 PM PST this afternoon Northern
     Clearwater Mountains.

     Winter Storm Warning until 4 PM PST this afternoon Southern
     Clearwater Mountains.

     Winter Weather Advisory until 4 PM PST this afternoon
     Orofino/Grangeville Region.

&&

Special Weather Statement...CORRECTED
National Weather Service Missoula MT
1216 PM MST Fri Feb 26 2021

IDZ006-MTZ005-006-261945-
Southern Clearwater Mountains ID-Bitterroot/Sapphire Mountains MT-
Missoula/Bitterroot Valleys MT-
1216 PM MST Fri Feb 26 2021 /1116 AM PST Fri Feb 26 2021/

...SIGNIFICANT WEATHER ADVISORY FOR NORTHEASTERN IDAHO...SOUTH
CENTRAL MISSOULA...NORTH CENTRAL RAVALLI AND NORTHWESTERN GRANITE
COUNTIES UNTIL 1245 PM MST...

At 1144 AM MST, Doppler radar was tracking a strong snow band near
Stevensville, or 20 miles north of Hamilton.

Visibility one-half mile or less will be possible. Snow and slush
will accumulate up to 1 inch on roads surfaces and wind gusts up to
25 MPH.

Locations impacted include...
Stevensville, Florence, Quigley and Bell Crossing.

LAT...LON 4646 11436 4669 11432 4667 11350 4634 11358
TIME...MOT...LOC 1844Z 278DEG 23KT 4655 11423

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE MISSOULA MT
1228 PM MST FRI FEB 26 2021

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

1227 PM     SNOW             2 WNW STEVENSVILLE      46.52N 114.13W
02/26/2021  E4.0 INCH        RAVALLI            MT   TRAINED SPOTTER

&&

IV

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE MISSOULA MT
1243 PM MST FRI FEB 26 2021

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

1242 PM     SNOW             STEVENSVILLE            46.51N 114.09W
02/26/2021  E2.0 INCH        RAVALLI            MT   PUBLIC

&&

IV

Special Weather Statement
National Weather Service Missoula MT
1246 PM MST Fri Feb 26 2021

MTZ005-006-262045-
Bitterroot/Sapphire Mountains MT-Missoula/Bitterroot Valleys MT-
1246 PM MST Fri Feb 26 2021

...SIGNIFICANT WEATHER ADVISORY FOR NORTH CENTRAL RAVALLI AND WEST
CENTRAL GRANITE COUNTIES UNTIL 145 PM MST...

At 1245 PM MST, Doppler radar was tracking an intense snow shower
over Victor, or 11 miles north of Hamilton, moving east at 25 mph.

Visibility one-half mile or less will be possible. Snow and slush
accumulation of up to 1 inch possible and winds gusting to 25 mph.

Locations impacted include...
Victor and Bell Crossing.

LAT...LON 4638 11430 4651 11428 4646 11346 4629 11350
TIME...MOT...LOC 1945Z 277DEG 23KT 4642 11419

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE MISSOULA MT
1253 PM MST FRI FEB 26 2021

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

1253 PM     SNOW             RED RIVER HOT SPRING    45.79N 115.20W
02/26/2021  E6.0 INCH        IDAHO              ID   PUBLIC

            FACEBOOK REPORT. BETWEEN 5 FEET AND 6 FEET
            OF SNOW ON THE GROUND.

&&

IV

Special Weather Statement
National Weather Service Missoula MT
105 PM MST Fri Feb 26 2021

MTZ006-007-262045-
Bitterroot/Sapphire Mountains MT-Butte/Blackfoot Region MT-
105 PM MST Fri Feb 26 2021

...SIGNIFICANT WEATHER ADVISORY FOR EAST CENTRAL GRANITE AND SOUTH
CENTRAL POWELL COUNTIES UNTIL 145 PM MST...

At 104 PM MST, Doppler radar was tracking two intense snow showers 8
miles northwest of Philipsburg, or 19 miles southwest of Drummond,
moving east at 25 mph.

Visibility one-half mile or less will be possible. Snow and slush
accumulations of up to 1 inch are possible and wind gusts to 25 MPH.

Locations impacted include...
Princeton and Maxville.

LAT...LON 4638 11348 4659 11343 4652 11286 4630 11290
TIME...MOT...LOC 2004Z 276DEG 22KT 4643 11338