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000
FXUS65 KMSO 270933
AFDMSO

Area Forecast Discussion
National Weather Service Missoula MT
333 AM MDT MON APR 27 2015

.DISCUSSION...Fog and low clouds have developed in valleys of
central Idaho and western Montana. Expect fog to dissipate later
this morning giving way to a rather pleasant spring day. High
temperatures will rise into the 60s. With the upper level ridge
shifting eastward on Tuesday, high temperatures will soar into the
70s to near 80 in some places.

A cold front will bring cooler temperatures, clouds, showers and
breezy conditions by Wednesday. There isn`t much moisture to work
with as this front moves through allowing for a better chance for
showers in the mountains rather than the valleys. Left the chance
for isolated thunderstorms across Lemhi County and Silver Bow
County including Butte. The main impact with the stronger showers
will be gusty winds especially in the Butte area.

For the latter half of this week, forecast models have settled on
a drier westerly flow pattern over the Northern Rockies. This will
bring quiet weather and near-normal temperatures through the end
of the work week. Models do hint at a weak weather disturbance
brushing the Continental Divide for the weekend, bringing a chance
of showers and potentially breezy conditions.

&&

.AVIATION...Low stratus and fog have developed in the valleys
across central Idaho into western Montana, mostly affecting KMSO
and KGPI but possibly impacting KSMN and KBTM by daybreak. Expect
improvement by 27/1700z most areas. VFR conditions are expected
for the remainder of today and also on Tuesday at all the
terminals with sunny skies and light winds. Couldn`t rule out
patchy fog Tuesday morning but confidence is lower.


&&

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

$$





000
FXUS65 KMSO 270933
AFDMSO

Area Forecast Discussion
National Weather Service Missoula MT
333 AM MDT MON APR 27 2015

.DISCUSSION...Fog and low clouds have developed in valleys of
central Idaho and western Montana. Expect fog to dissipate later
this morning giving way to a rather pleasant spring day. High
temperatures will rise into the 60s. With the upper level ridge
shifting eastward on Tuesday, high temperatures will soar into the
70s to near 80 in some places.

A cold front will bring cooler temperatures, clouds, showers and
breezy conditions by Wednesday. There isn`t much moisture to work
with as this front moves through allowing for a better chance for
showers in the mountains rather than the valleys. Left the chance
for isolated thunderstorms across Lemhi County and Silver Bow
County including Butte. The main impact with the stronger showers
will be gusty winds especially in the Butte area.

For the latter half of this week, forecast models have settled on
a drier westerly flow pattern over the Northern Rockies. This will
bring quiet weather and near-normal temperatures through the end
of the work week. Models do hint at a weak weather disturbance
brushing the Continental Divide for the weekend, bringing a chance
of showers and potentially breezy conditions.

&&

.AVIATION...Low stratus and fog have developed in the valleys
across central Idaho into western Montana, mostly affecting KMSO
and KGPI but possibly impacting KSMN and KBTM by daybreak. Expect
improvement by 27/1700z most areas. VFR conditions are expected
for the remainder of today and also on Tuesday at all the
terminals with sunny skies and light winds. Couldn`t rule out
patchy fog Tuesday morning but confidence is lower.


&&

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

$$




000
FXUS65 KMSO 262040
AFDMSO

Area Forecast Discussion
National Weather Service Missoula MT
240 PM MDT SUN APR 26 2015

.DISCUSSION...Rain and snow showers will continue into this
afternoon as a trough continues to move through Idaho and western
Montana. Showers will decrease by this evening and skies will
begin to clear once the system moves off to the east. Decreased
cloud cover tonight will result in a combination of patchy fog and
cool Monday morning temperatures. Places that end up with clear
skies and without fog will fall below freezing with low
temperatures in the upper 20s. Spots that have had precipitation
today are more likely to see patchy fog so temperatures may not
drop quite as low.

High pressure Monday into Tuesday will produce very nice spring
days with above average high temperatures and sunshine. Tuesday
still looks like the warmest day, with many valley locations
expected to reach into the mid to upper 70s!

Wednesday will bring a change in the weather as an upper level
trough of low pressure and associated cold front will move through
the region. This will result in cooler temperatures, increased
clouds, showers and breezy winds.

Forecast models have been inconsistent in the timing of weather
systems beyond Thursday. But the overall pattern through Sunday looks
like a typical spring pattern with a few showery/breezy days and
high temperatures around the 60s.

&&

.AVIATION...Cloud cover remains through much of north central
Idaho and western Montana this afternoon as a weather system
begins to exit the region. Rain and snow are still common along
the divide and showers are quickly developing in western Montana.
High resolution model guidance agree that precipitation will
decrease late this afternoon as well as cloud cover from west to
east. Clearing skies overnight along with precipitation from the
day will allow for patchy fog to develop in many of the valley of
north central Idaho and western Montana Monday morning. After fog
dissipates mid-Monday morning high pressure will result in mostly
sunny skies and light winds.



&&

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

$$





000
FXUS65 KMSO 262040
AFDMSO

Area Forecast Discussion
National Weather Service Missoula MT
240 PM MDT SUN APR 26 2015

.DISCUSSION...Rain and snow showers will continue into this
afternoon as a trough continues to move through Idaho and western
Montana. Showers will decrease by this evening and skies will
begin to clear once the system moves off to the east. Decreased
cloud cover tonight will result in a combination of patchy fog and
cool Monday morning temperatures. Places that end up with clear
skies and without fog will fall below freezing with low
temperatures in the upper 20s. Spots that have had precipitation
today are more likely to see patchy fog so temperatures may not
drop quite as low.

High pressure Monday into Tuesday will produce very nice spring
days with above average high temperatures and sunshine. Tuesday
still looks like the warmest day, with many valley locations
expected to reach into the mid to upper 70s!

Wednesday will bring a change in the weather as an upper level
trough of low pressure and associated cold front will move through
the region. This will result in cooler temperatures, increased
clouds, showers and breezy winds.

Forecast models have been inconsistent in the timing of weather
systems beyond Thursday. But the overall pattern through Sunday looks
like a typical spring pattern with a few showery/breezy days and
high temperatures around the 60s.

&&

.AVIATION...Cloud cover remains through much of north central
Idaho and western Montana this afternoon as a weather system
begins to exit the region. Rain and snow are still common along
the divide and showers are quickly developing in western Montana.
High resolution model guidance agree that precipitation will
decrease late this afternoon as well as cloud cover from west to
east. Clearing skies overnight along with precipitation from the
day will allow for patchy fog to develop in many of the valley of
north central Idaho and western Montana Monday morning. After fog
dissipates mid-Monday morning high pressure will result in mostly
sunny skies and light winds.



&&

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

$$




000
FXUS65 KMSO 261007
AFDMSO

Area Forecast Discussion
National Weather Service Missoula MT
407 AM MDT SUN APR 26 2015

...Snow across Lemhi County ID and higher mountain passes will
taper to showers by this afternoon...

.DISCUSSION...Snow levels are generally around 5000 feet as of 3
am MDT and may fall as low as 4000 feet in a few hours across
southwest Montana. Snow has been sticking to Lost Trail Pass while
web cams reveal snow sticking to grassy surfaces at other
locations. There is still a chance that locations across the
southern Bitterroot Valley above 4000 feet could experience a
period heavy snow for a period towards daybreak. Expect the
steady precipitation to change to showers by this afternoon.
Drying expected to occur by tonight.

High pressure quickly builds into western Montana and north central
Idaho Sunday night and lasts through mid week. This will result
in much warmer and drier conditions, with many valleys approaching
the mid to even upper 70s by Tuesday afternoon. Mornings will
start off chilly, especially on Monday morning when some valleys
of western Montana could briefly dip below freezing, perhaps locally
into the upper 20s.

Southwest flow ahead of an approaching trough Wednesday will allow
for the return of showers and slightly cooler temperatures, with a
few thunderstorms possible as well over southwest MT Wednesday
afternoon. Breezy winds can also be expected Wednesday afternoon.

Forecast models have changed course yet again for the rest of the
week and into the weekend, now showing a generally drier westerly
flow. Overall, forecast confidence is low for this period. For
now, have kept the forecast near climatology, which is generally
cooler temperatures than earlier in the week, and chances of
showers mainly over the mountains.

&&

.AVIATION...Reductions to ceilings and visibility will continue
this morning from KBTM, west to the Bitterroot Valley then south
to KSMN. Expect improvement after 26/1800z as the weather system
moves off to the east. North to east winds to 20 knots have been
observed at weather stations along and west of the Continental
Divide. Expect these winds to diminish somewhat by after 25/1800z. Showers
are anticipated this afternoon but should decrease in coverage
after 27/0000z as an upper level ridge builds into the region.


&&

.MSO WATCHES/WARNINGS/ADVISORIES...
MT...WINTER WEATHER ADVISORY until 3 PM MDT this afternoon
     Butte/Blackfoot Region.

     WINTER WEATHER ADVISORY until 3 PM MDT this afternoon
     Bitterroot/Sapphire Mountains.

     WINTER WEATHER ADVISORY until 10 AM MDT this morning ABOVE 4000
     FEET for the Missoula/Bitterroot Valleys.

ID...     WINTER WEATHER ADVISORY until 3 PM MDT this afternoon Eastern
     Lemhi County.

&&

$$




000
FXUS65 KMSO 260504
AFDMSO

Area Forecast Discussion
National Weather Service Missoula MT
1104 PM MDT SAT APR 25 2015

.DISCUSSION...

High-resolution forecast models this evening are indicating a
focused area of heavy precipitation forming overnight in western
Montana, particularly in the southern Bitterroot Valley. While
most guidance keeps snow levels above valley floors, we`re
thinking the precipitation intensity will be able to pull snow
levels as low as perhaps 3500 feet, which could bring accumulating
snow from Hamilton to Darby. Impacts should be minor for those
areas. The real concern is rural locations above 4000 feet on the
periphery of the valley which could see wet heavy snow, enough to
snap tree limbs and bring power outages. There is enough concern
that we added a winter weather advisory with a focus on the
southern Bitterroot Valley for tonight into tomorrow morning.

&&

.PREV DISCUSSION... /ISSUED 301 PM MDT SAT APR 25 2015/

..SNOW TO DEVELOP TONIGHT IN LEMHI COUNTY ID AND SOUTHWEST MT...

DISCUSSION...Rain and snow showers are developing this afternoon
ahead of the next weather system. These showers will expand
through the region this evening while the next trough moves into
Idaho and western Montana. This trough will interact with a low
pressure system to the south with the main focus of precipitation
to be through Lemhi County, Idaho and in southwest Montana. Snow
is expected to develop overnight for Lolo, Lost Trail, Bannock,
Lemhi, Homestake, and MacDonald passes through Sunday morning.
Moderate to heavy snow will result in slushy snow accumulations
with periods of difficult travel, so Winter Weather Advisories
have been issued for the previously listed passes and for Butte
and Georgetown Lake. There is a chance for snow levels to lower
under heavy precipitation in the Missoula/Bitterroot valley so a
mix of rain and snow will be common Sunday morning with light snow
accumulations possible from Hamilton southward. Precipitation will
become more showery during Sunday afternoon.

High pressure quickly builds into western Montana and north central
Idaho Sunday night and lasts through mid week. This will result
in much warmer and drier conditions, with many valleys approaching
the mid to even upper 70s by Tuesday afternoon. Mornings will
start off chilly, especially on Monday morning when some valleys
of western Montana could briefly dip below freezing, possibly
locally into the upper 20s.

Southwest flow ahead of an approaching trough Wednesday will allow
for the return of showers and slightly cooler temperatures.
Forecast models have trended more towards a wet and cooler pattern
beginning on Thursday, and thus the forecast has been adjusted in
this direction.

AVIATION...Rain and snow showers will be on the increase this
afternoon at all area terminals. Brief visibility reductions and
lower ceilings should be expected for this afternoon. A secondary
surge of moisture is expected tonight and could bring prolonged
periods of moderate snow at KBTM on Sunday morning. During this
time, mountains will be obscured and ceilings/visibility will
significantly lower. The snow is expected to transition to rain
around mid day Sunday. KMSO and KSMN should see the rain showers
transition to wet snow overnight tonight. Low ceilings and
mountain obscurations should be expected for Sunday morning.

&&

.MSO WATCHES/WARNINGS/ADVISORIES...
MT...WINTER WEATHER ADVISORY until 3 PM MDT Sunday Butte/Blackfoot
     Region.

     WINTER WEATHER ADVISORY until 3 PM MDT Sunday
     Bitterroot/Sapphire Mountains.

     WINTER WEATHER ADVISORY until 10 AM MDT Sunday ABOVE 4000 FEET
     for the Missoula/Bitterroot Valleys.

ID...     WINTER WEATHER ADVISORY until 3 PM MDT Sunday Eastern Lemhi
     County.

&&

$$




000
FXUS65 KMSO 260504
AFDMSO

Area Forecast Discussion
National Weather Service Missoula MT
1104 PM MDT SAT APR 25 2015

.DISCUSSION...

High-resolution forecast models this evening are indicating a
focused area of heavy precipitation forming overnight in western
Montana, particularly in the southern Bitterroot Valley. While
most guidance keeps snow levels above valley floors, we`re
thinking the precipitation intensity will be able to pull snow
levels as low as perhaps 3500 feet, which could bring accumulating
snow from Hamilton to Darby. Impacts should be minor for those
areas. The real concern is rural locations above 4000 feet on the
periphery of the valley which could see wet heavy snow, enough to
snap tree limbs and bring power outages. There is enough concern
that we added a winter weather advisory with a focus on the
southern Bitterroot Valley for tonight into tomorrow morning.

&&

.PREV DISCUSSION... /ISSUED 301 PM MDT SAT APR 25 2015/

..SNOW TO DEVELOP TONIGHT IN LEMHI COUNTY ID AND SOUTHWEST MT...

DISCUSSION...Rain and snow showers are developing this afternoon
ahead of the next weather system. These showers will expand
through the region this evening while the next trough moves into
Idaho and western Montana. This trough will interact with a low
pressure system to the south with the main focus of precipitation
to be through Lemhi County, Idaho and in southwest Montana. Snow
is expected to develop overnight for Lolo, Lost Trail, Bannock,
Lemhi, Homestake, and MacDonald passes through Sunday morning.
Moderate to heavy snow will result in slushy snow accumulations
with periods of difficult travel, so Winter Weather Advisories
have been issued for the previously listed passes and for Butte
and Georgetown Lake. There is a chance for snow levels to lower
under heavy precipitation in the Missoula/Bitterroot valley so a
mix of rain and snow will be common Sunday morning with light snow
accumulations possible from Hamilton southward. Precipitation will
become more showery during Sunday afternoon.

High pressure quickly builds into western Montana and north central
Idaho Sunday night and lasts through mid week. This will result
in much warmer and drier conditions, with many valleys approaching
the mid to even upper 70s by Tuesday afternoon. Mornings will
start off chilly, especially on Monday morning when some valleys
of western Montana could briefly dip below freezing, possibly
locally into the upper 20s.

Southwest flow ahead of an approaching trough Wednesday will allow
for the return of showers and slightly cooler temperatures.
Forecast models have trended more towards a wet and cooler pattern
beginning on Thursday, and thus the forecast has been adjusted in
this direction.

AVIATION...Rain and snow showers will be on the increase this
afternoon at all area terminals. Brief visibility reductions and
lower ceilings should be expected for this afternoon. A secondary
surge of moisture is expected tonight and could bring prolonged
periods of moderate snow at KBTM on Sunday morning. During this
time, mountains will be obscured and ceilings/visibility will
significantly lower. The snow is expected to transition to rain
around mid day Sunday. KMSO and KSMN should see the rain showers
transition to wet snow overnight tonight. Low ceilings and
mountain obscurations should be expected for Sunday morning.

&&

.MSO WATCHES/WARNINGS/ADVISORIES...
MT...WINTER WEATHER ADVISORY until 3 PM MDT Sunday Butte/Blackfoot
     Region.

     WINTER WEATHER ADVISORY until 3 PM MDT Sunday
     Bitterroot/Sapphire Mountains.

     WINTER WEATHER ADVISORY until 10 AM MDT Sunday ABOVE 4000 FEET
     for the Missoula/Bitterroot Valleys.

ID...     WINTER WEATHER ADVISORY until 3 PM MDT Sunday Eastern Lemhi
     County.

&&

$$





000
FXUS65 KMSO 260504
AFDMSO

Area Forecast Discussion
National Weather Service Missoula MT
1104 PM MDT SAT APR 25 2015

.DISCUSSION...

High-resolution forecast models this evening are indicating a
focused area of heavy precipitation forming overnight in western
Montana, particularly in the southern Bitterroot Valley. While
most guidance keeps snow levels above valley floors, we`re
thinking the precipitation intensity will be able to pull snow
levels as low as perhaps 3500 feet, which could bring accumulating
snow from Hamilton to Darby. Impacts should be minor for those
areas. The real concern is rural locations above 4000 feet on the
periphery of the valley which could see wet heavy snow, enough to
snap tree limbs and bring power outages. There is enough concern
that we added a winter weather advisory with a focus on the
southern Bitterroot Valley for tonight into tomorrow morning.

&&

.PREV DISCUSSION... /ISSUED 301 PM MDT SAT APR 25 2015/

..SNOW TO DEVELOP TONIGHT IN LEMHI COUNTY ID AND SOUTHWEST MT...

DISCUSSION...Rain and snow showers are developing this afternoon
ahead of the next weather system. These showers will expand
through the region this evening while the next trough moves into
Idaho and western Montana. This trough will interact with a low
pressure system to the south with the main focus of precipitation
to be through Lemhi County, Idaho and in southwest Montana. Snow
is expected to develop overnight for Lolo, Lost Trail, Bannock,
Lemhi, Homestake, and MacDonald passes through Sunday morning.
Moderate to heavy snow will result in slushy snow accumulations
with periods of difficult travel, so Winter Weather Advisories
have been issued for the previously listed passes and for Butte
and Georgetown Lake. There is a chance for snow levels to lower
under heavy precipitation in the Missoula/Bitterroot valley so a
mix of rain and snow will be common Sunday morning with light snow
accumulations possible from Hamilton southward. Precipitation will
become more showery during Sunday afternoon.

High pressure quickly builds into western Montana and north central
Idaho Sunday night and lasts through mid week. This will result
in much warmer and drier conditions, with many valleys approaching
the mid to even upper 70s by Tuesday afternoon. Mornings will
start off chilly, especially on Monday morning when some valleys
of western Montana could briefly dip below freezing, possibly
locally into the upper 20s.

Southwest flow ahead of an approaching trough Wednesday will allow
for the return of showers and slightly cooler temperatures.
Forecast models have trended more towards a wet and cooler pattern
beginning on Thursday, and thus the forecast has been adjusted in
this direction.

AVIATION...Rain and snow showers will be on the increase this
afternoon at all area terminals. Brief visibility reductions and
lower ceilings should be expected for this afternoon. A secondary
surge of moisture is expected tonight and could bring prolonged
periods of moderate snow at KBTM on Sunday morning. During this
time, mountains will be obscured and ceilings/visibility will
significantly lower. The snow is expected to transition to rain
around mid day Sunday. KMSO and KSMN should see the rain showers
transition to wet snow overnight tonight. Low ceilings and
mountain obscurations should be expected for Sunday morning.

&&

.MSO WATCHES/WARNINGS/ADVISORIES...
MT...WINTER WEATHER ADVISORY until 3 PM MDT Sunday Butte/Blackfoot
     Region.

     WINTER WEATHER ADVISORY until 3 PM MDT Sunday
     Bitterroot/Sapphire Mountains.

     WINTER WEATHER ADVISORY until 10 AM MDT Sunday ABOVE 4000 FEET
     for the Missoula/Bitterroot Valleys.

ID...     WINTER WEATHER ADVISORY until 3 PM MDT Sunday Eastern Lemhi
     County.

&&

$$





000
FXUS65 KMSO 260504
AFDMSO

Area Forecast Discussion
National Weather Service Missoula MT
1104 PM MDT SAT APR 25 2015

.DISCUSSION...

High-resolution forecast models this evening are indicating a
focused area of heavy precipitation forming overnight in western
Montana, particularly in the southern Bitterroot Valley. While
most guidance keeps snow levels above valley floors, we`re
thinking the precipitation intensity will be able to pull snow
levels as low as perhaps 3500 feet, which could bring accumulating
snow from Hamilton to Darby. Impacts should be minor for those
areas. The real concern is rural locations above 4000 feet on the
periphery of the valley which could see wet heavy snow, enough to
snap tree limbs and bring power outages. There is enough concern
that we added a winter weather advisory with a focus on the
southern Bitterroot Valley for tonight into tomorrow morning.

&&

.PREV DISCUSSION... /ISSUED 301 PM MDT SAT APR 25 2015/

..SNOW TO DEVELOP TONIGHT IN LEMHI COUNTY ID AND SOUTHWEST MT...

DISCUSSION...Rain and snow showers are developing this afternoon
ahead of the next weather system. These showers will expand
through the region this evening while the next trough moves into
Idaho and western Montana. This trough will interact with a low
pressure system to the south with the main focus of precipitation
to be through Lemhi County, Idaho and in southwest Montana. Snow
is expected to develop overnight for Lolo, Lost Trail, Bannock,
Lemhi, Homestake, and MacDonald passes through Sunday morning.
Moderate to heavy snow will result in slushy snow accumulations
with periods of difficult travel, so Winter Weather Advisories
have been issued for the previously listed passes and for Butte
and Georgetown Lake. There is a chance for snow levels to lower
under heavy precipitation in the Missoula/Bitterroot valley so a
mix of rain and snow will be common Sunday morning with light snow
accumulations possible from Hamilton southward. Precipitation will
become more showery during Sunday afternoon.

High pressure quickly builds into western Montana and north central
Idaho Sunday night and lasts through mid week. This will result
in much warmer and drier conditions, with many valleys approaching
the mid to even upper 70s by Tuesday afternoon. Mornings will
start off chilly, especially on Monday morning when some valleys
of western Montana could briefly dip below freezing, possibly
locally into the upper 20s.

Southwest flow ahead of an approaching trough Wednesday will allow
for the return of showers and slightly cooler temperatures.
Forecast models have trended more towards a wet and cooler pattern
beginning on Thursday, and thus the forecast has been adjusted in
this direction.

AVIATION...Rain and snow showers will be on the increase this
afternoon at all area terminals. Brief visibility reductions and
lower ceilings should be expected for this afternoon. A secondary
surge of moisture is expected tonight and could bring prolonged
periods of moderate snow at KBTM on Sunday morning. During this
time, mountains will be obscured and ceilings/visibility will
significantly lower. The snow is expected to transition to rain
around mid day Sunday. KMSO and KSMN should see the rain showers
transition to wet snow overnight tonight. Low ceilings and
mountain obscurations should be expected for Sunday morning.

&&

.MSO WATCHES/WARNINGS/ADVISORIES...
MT...WINTER WEATHER ADVISORY until 3 PM MDT Sunday Butte/Blackfoot
     Region.

     WINTER WEATHER ADVISORY until 3 PM MDT Sunday
     Bitterroot/Sapphire Mountains.

     WINTER WEATHER ADVISORY until 10 AM MDT Sunday ABOVE 4000 FEET
     for the Missoula/Bitterroot Valleys.

ID...     WINTER WEATHER ADVISORY until 3 PM MDT Sunday Eastern Lemhi
     County.

&&

$$




000
FXUS65 KMSO 252101
AFDMSO

Area Forecast Discussion
National Weather Service Missoula MT
301 PM MDT SAT APR 25 2015

...SNOW TO DEVELOP TONIGHT IN LEMHI COUNTY ID AND SOUTHWEST MT...

.DISCUSSION...Rain and snow showers are developing this afternoon
ahead of the next weather system. These showers will expand
through the region this evening while the next trough moves into
Idaho and western Montana. This trough will interact with a low
pressure system to the south with the main focus of precipitation
to be through Lemhi County, Idaho and in southwest Montana. Snow
is expected to develop overnight for Lolo, Lost Trail, Bannock,
Lemhi, Homestake, and MacDonald passes through Sunday morning.
Moderate to heavy snow will result in slushy snow accumulations
with periods of difficult travel, so Winter Weather Advisories
have been issued for the previously listed passes and for Butte
and Georgetown Lake. There is a chance for snow levels to lower
under heavy precipitation in the Missoula/Bitterroot valley so a
mix of rain and snow will be common Sunday morning with light snow
accumulations possible from Hamilton southward. Precipitation will
become more showery during Sunday afternoon.

High pressure quickly builds into western Montana and north central
Idaho Sunday night and lasts through mid week. This will result
in much warmer and drier conditions, with many valleys approaching
the mid to even upper 70s by Tuesday afternoon. Mornings will
start off chilly, especially on Monday morning when some valleys
of western Montana could briefly dip below freezing, possibly
locally into the upper 20s.

Southwest flow ahead of an approaching trough Wednesday will allow
for the return of showers and slightly cooler temperatures.
Forecast models have trended more towards a wet and cooler pattern
beginning on Thursday, and thus the forecast has been adjusted in
this direction.

&&

.AVIATION...Rain and snow showers will be on the increase this
afternoon at all area terminals. Brief visibility reductions and
lower ceilings should be expected for this afternoon. A secondary
surge of moisture is expected tonight and could bring prolonged
periods of moderate snow at KBTM on Sunday morning. During this
time, mountains will be obscured and ceilings/visibility will
significantly lower. The snow is expected to transition to rain
around mid day Sunday. KMSO and KSMN should see the rain showers
transition to wet snow overnight tonight. Low ceilings and
mountain obscurations should be expected for Sunday morning.

&&

.MSO WATCHES/WARNINGS/ADVISORIES...
MT...WINTER WEATHER ADVISORY from 9 PM this evening to 3 PM MDT
     Sunday Butte/Blackfoot Region.

     WINTER WEATHER ADVISORY from 9 PM this evening to 3 PM MDT
     Sunday Bitterroot/Sapphire Mountains.

ID...     WINTER WEATHER ADVISORY from 9 PM this evening to 3 PM MDT
     Sunday Eastern Lemhi County.

&&

$$




000
FXUS65 KMSO 252101
AFDMSO

Area Forecast Discussion
National Weather Service Missoula MT
301 PM MDT SAT APR 25 2015

...SNOW TO DEVELOP TONIGHT IN LEMHI COUNTY ID AND SOUTHWEST MT...

.DISCUSSION...Rain and snow showers are developing this afternoon
ahead of the next weather system. These showers will expand
through the region this evening while the next trough moves into
Idaho and western Montana. This trough will interact with a low
pressure system to the south with the main focus of precipitation
to be through Lemhi County, Idaho and in southwest Montana. Snow
is expected to develop overnight for Lolo, Lost Trail, Bannock,
Lemhi, Homestake, and MacDonald passes through Sunday morning.
Moderate to heavy snow will result in slushy snow accumulations
with periods of difficult travel, so Winter Weather Advisories
have been issued for the previously listed passes and for Butte
and Georgetown Lake. There is a chance for snow levels to lower
under heavy precipitation in the Missoula/Bitterroot valley so a
mix of rain and snow will be common Sunday morning with light snow
accumulations possible from Hamilton southward. Precipitation will
become more showery during Sunday afternoon.

High pressure quickly builds into western Montana and north central
Idaho Sunday night and lasts through mid week. This will result
in much warmer and drier conditions, with many valleys approaching
the mid to even upper 70s by Tuesday afternoon. Mornings will
start off chilly, especially on Monday morning when some valleys
of western Montana could briefly dip below freezing, possibly
locally into the upper 20s.

Southwest flow ahead of an approaching trough Wednesday will allow
for the return of showers and slightly cooler temperatures.
Forecast models have trended more towards a wet and cooler pattern
beginning on Thursday, and thus the forecast has been adjusted in
this direction.

&&

.AVIATION...Rain and snow showers will be on the increase this
afternoon at all area terminals. Brief visibility reductions and
lower ceilings should be expected for this afternoon. A secondary
surge of moisture is expected tonight and could bring prolonged
periods of moderate snow at KBTM on Sunday morning. During this
time, mountains will be obscured and ceilings/visibility will
significantly lower. The snow is expected to transition to rain
around mid day Sunday. KMSO and KSMN should see the rain showers
transition to wet snow overnight tonight. Low ceilings and
mountain obscurations should be expected for Sunday morning.

&&

.MSO WATCHES/WARNINGS/ADVISORIES...
MT...WINTER WEATHER ADVISORY from 9 PM this evening to 3 PM MDT
     Sunday Butte/Blackfoot Region.

     WINTER WEATHER ADVISORY from 9 PM this evening to 3 PM MDT
     Sunday Bitterroot/Sapphire Mountains.

ID...     WINTER WEATHER ADVISORY from 9 PM this evening to 3 PM MDT
     Sunday Eastern Lemhi County.

&&

$$





000
FXUS65 KMSO 250921
AFDMSO

Area Forecast Discussion
National Weather Service Missoula MT
321 AM MDT SAT APR 25 2015

...Spring storm will bring SNOW to Mountain Passes & high valleys
across southwest Montana tonight...

.DISCUSSION...The upper level wave that brought snow to portions
of southwest Montana including Homestake Pass last night will be
departing to the east this morning. A large upper level low, as
seen swirling counter-clockwise in water vapor satellite imagery
centered over southwestern British Columbia and northwest
Washington State, will slowly shift eastward today. Showers will
be on the increase across central Idaho and into northwest-
western Montana by early this afternoon. Have added a chance for
isolated thunder along the Idaho and Montana border as there will
be marginal instability there this afternoon. The Flathead,
Mission, Missoula and Bitterroot Valleys may be able to avoid much
of the shower activity through this evening.

The upper level trough pinches off into a secondary system over
southern Idaho tonight. At the same time, a mid-level low develops
across western Wyoming with troughiness extending north and west
into southwestern Montana. This will bring wet snow to mountain
passes including Lolo, Lost Trail, Bannock, Gilmore and Homestake
by Sunday morning, and even to the high valleys above 5000 feet
including Butte. Generally 1 to 2 inches is expected currently,
while Lost Trail, Georgetown Lake and the higher elevations south
of Butte may be able to see a little bit more. The bulk of the
precipitation will fall between midnight and 11 am MDT. Area
roadways will become slick at times during this period. There is a
chance that Lookout Pass may be able to see light snow as recent
weather models have increased their precipitation amounts there,
but confidence is also lower in that vicinity. There is also a
chance that snow makes it down to 4000 feet across the southern
Bitterroot Valley from Darby southwards, but probably would only
stick to grassy surfaces.

The northern trough swings through western Montana Sunday
afternoon and will bring scattered rain showers to the region.
Have lowered temperatures across southwest Montana as cloudiness
and precipitation may linger into Sunday afternoon reducing any
chance for any substantial solar heating to occur. An upper-level
ridge builds in behind this system Sunday night bringing an end to
the precipitation.

Dry and warmer weather is on the way for the first part of next
week. Valley highs could reach the mid 70s or higher by the time
the upper-level ridge is directly overhead, which looks to be
Tuesday. In fact, current guidance would bring the warmest temps
yet this season for Missoula by Tues/Wed.

The flow aloft shifts to southwesterly for the latter half of
next week, bringing a more moist airmass back into the region and
allowing several weak disturbances to move through along with a
general cooling trend. The details remain fuzzy at this point, but
current indications point to Friday and Saturday having the best
chance of showers along with near to slightly below-normal
temperatures.

&&

.AVIATION...Showers will be on the increase today across central
Idaho by 25/1800z and into western Montana by 25/2000z. There may
be just enough instability to support an isolated thunderstorm
with small graupel mainly north and west of Superior, MT in the
mountains and also south and east of Elk City, Idaho. There could
be shower-induced winds to 15 knots mainly at KSMN and KBTM
between 25/1900z and 26/0000z. For KGPI, showers should mainly be
situated over the surrounding terrain and may not affect the
terminal at all. A storm system brings rain and snow to the region
after 26/0000z continuing through at least 26/1800z Sunday. KBTM
has the highest chance of seeing the lowest ceilings and
visibility due to snow, especially between 26/0900z and 26/1800z. KSMN
will see lower ceilings with mostly rain. Expect obscured terrain
along the Idaho & Montana border into western Montana during the
time period, while the Glacier National Park region may be spared.


&&

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

$$




000
FXUS65 KMSO 250921
AFDMSO

Area Forecast Discussion
National Weather Service Missoula MT
321 AM MDT SAT APR 25 2015

...Spring storm will bring SNOW to Mountain Passes & high valleys
across southwest Montana tonight...

.DISCUSSION...The upper level wave that brought snow to portions
of southwest Montana including Homestake Pass last night will be
departing to the east this morning. A large upper level low, as
seen swirling counter-clockwise in water vapor satellite imagery
centered over southwestern British Columbia and northwest
Washington State, will slowly shift eastward today. Showers will
be on the increase across central Idaho and into northwest-
western Montana by early this afternoon. Have added a chance for
isolated thunder along the Idaho and Montana border as there will
be marginal instability there this afternoon. The Flathead,
Mission, Missoula and Bitterroot Valleys may be able to avoid much
of the shower activity through this evening.

The upper level trough pinches off into a secondary system over
southern Idaho tonight. At the same time, a mid-level low develops
across western Wyoming with troughiness extending north and west
into southwestern Montana. This will bring wet snow to mountain
passes including Lolo, Lost Trail, Bannock, Gilmore and Homestake
by Sunday morning, and even to the high valleys above 5000 feet
including Butte. Generally 1 to 2 inches is expected currently,
while Lost Trail, Georgetown Lake and the higher elevations south
of Butte may be able to see a little bit more. The bulk of the
precipitation will fall between midnight and 11 am MDT. Area
roadways will become slick at times during this period. There is a
chance that Lookout Pass may be able to see light snow as recent
weather models have increased their precipitation amounts there,
but confidence is also lower in that vicinity. There is also a
chance that snow makes it down to 4000 feet across the southern
Bitterroot Valley from Darby southwards, but probably would only
stick to grassy surfaces.

The northern trough swings through western Montana Sunday
afternoon and will bring scattered rain showers to the region.
Have lowered temperatures across southwest Montana as cloudiness
and precipitation may linger into Sunday afternoon reducing any
chance for any substantial solar heating to occur. An upper-level
ridge builds in behind this system Sunday night bringing an end to
the precipitation.

Dry and warmer weather is on the way for the first part of next
week. Valley highs could reach the mid 70s or higher by the time
the upper-level ridge is directly overhead, which looks to be
Tuesday. In fact, current guidance would bring the warmest temps
yet this season for Missoula by Tues/Wed.

The flow aloft shifts to southwesterly for the latter half of
next week, bringing a more moist airmass back into the region and
allowing several weak disturbances to move through along with a
general cooling trend. The details remain fuzzy at this point, but
current indications point to Friday and Saturday having the best
chance of showers along with near to slightly below-normal
temperatures.

&&

.AVIATION...Showers will be on the increase today across central
Idaho by 25/1800z and into western Montana by 25/2000z. There may
be just enough instability to support an isolated thunderstorm
with small graupel mainly north and west of Superior, MT in the
mountains and also south and east of Elk City, Idaho. There could
be shower-induced winds to 15 knots mainly at KSMN and KBTM
between 25/1900z and 26/0000z. For KGPI, showers should mainly be
situated over the surrounding terrain and may not affect the
terminal at all. A storm system brings rain and snow to the region
after 26/0000z continuing through at least 26/1800z Sunday. KBTM
has the highest chance of seeing the lowest ceilings and
visibility due to snow, especially between 26/0900z and 26/1800z. KSMN
will see lower ceilings with mostly rain. Expect obscured terrain
along the Idaho & Montana border into western Montana during the
time period, while the Glacier National Park region may be spared.


&&

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

$$





000
FXUS65 KMSO 242107
AFDMSO

Area Forecast Discussion
National Weather Service Missoula MT
307 PM MDT FRI APR 24 2015

...SNOW TO IMPACT ROADWAYS OVER MOUNTAIN PASSES TONIGHT...AND
AGAIN SATURDAY OVERNIGHT...

.DISCUSSION...

A relatively cool Pacific storm system will bring low elevation
rain and high elevation snow/rain mix to the Northern Rockies
through Sunday evening. Snow will create hazardous driving
conditions at times (overnight and morning hours) over area
mountain passes, particularly those along the Continental Divide
and above 6000 feet. Additionally, road surfaces near Butte,
Anaconda, and Georgetown Lake may see brief snow/slush on Saturday
morning and again on Sunday morning. Elsewhere, light rainfall
and cool temperatures will be commonplace.

Sunday night through Tuesday night, high pressure will return to
the Northern Rockies. Dry and warm conditions will prevail during
this time. In fact, the warmest temperatures of the year are
likely on afternoon.

High pressure is expected to break down Wednesday through next
weekend, with a series of weak storm systems moving across the
Northern Rockies. There is little consistency among operational
forecast models concerning the amount of moisture to be present
and the timing of each surface front. The current forecast
reflects low confidence and closely resembles climatology.

&&

.AVIATION...Rain showers will continue to bring low visibility
and ceilings to KBTM through this afternoon. At around 25/0000z,
showers are expected to gradually taper off but showers could
linger around KBTM through most of this evening. Cooler air will
be moving in tonight and will cause rain to transition to light snow
at KBTM. KSMN will also continue to see low ceilings and rain
showers through this evening. Another round of precipitation
develops late Saturday and will once again be focused over KBTM
and KSMN. This system looks to be stronger than the current one,
thus lower ceilings and visibilities should be expected Saturday
evening through Sunday.

&&

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

$$





000
FXUS65 KMSO 242107
AFDMSO

Area Forecast Discussion
National Weather Service Missoula MT
307 PM MDT FRI APR 24 2015

...SNOW TO IMPACT ROADWAYS OVER MOUNTAIN PASSES TONIGHT...AND
AGAIN SATURDAY OVERNIGHT...

.DISCUSSION...

A relatively cool Pacific storm system will bring low elevation
rain and high elevation snow/rain mix to the Northern Rockies
through Sunday evening. Snow will create hazardous driving
conditions at times (overnight and morning hours) over area
mountain passes, particularly those along the Continental Divide
and above 6000 feet. Additionally, road surfaces near Butte,
Anaconda, and Georgetown Lake may see brief snow/slush on Saturday
morning and again on Sunday morning. Elsewhere, light rainfall
and cool temperatures will be commonplace.

Sunday night through Tuesday night, high pressure will return to
the Northern Rockies. Dry and warm conditions will prevail during
this time. In fact, the warmest temperatures of the year are
likely on afternoon.

High pressure is expected to break down Wednesday through next
weekend, with a series of weak storm systems moving across the
Northern Rockies. There is little consistency among operational
forecast models concerning the amount of moisture to be present
and the timing of each surface front. The current forecast
reflects low confidence and closely resembles climatology.

&&

.AVIATION...Rain showers will continue to bring low visibility
and ceilings to KBTM through this afternoon. At around 25/0000z,
showers are expected to gradually taper off but showers could
linger around KBTM through most of this evening. Cooler air will
be moving in tonight and will cause rain to transition to light snow
at KBTM. KSMN will also continue to see low ceilings and rain
showers through this evening. Another round of precipitation
develops late Saturday and will once again be focused over KBTM
and KSMN. This system looks to be stronger than the current one,
thus lower ceilings and visibilities should be expected Saturday
evening through Sunday.

&&

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

$$




000
FXUS65 KMSO 242107
AFDMSO

Area Forecast Discussion
National Weather Service Missoula MT
307 PM MDT FRI APR 24 2015

...SNOW TO IMPACT ROADWAYS OVER MOUNTAIN PASSES TONIGHT...AND
AGAIN SATURDAY OVERNIGHT...

.DISCUSSION...

A relatively cool Pacific storm system will bring low elevation
rain and high elevation snow/rain mix to the Northern Rockies
through Sunday evening. Snow will create hazardous driving
conditions at times (overnight and morning hours) over area
mountain passes, particularly those along the Continental Divide
and above 6000 feet. Additionally, road surfaces near Butte,
Anaconda, and Georgetown Lake may see brief snow/slush on Saturday
morning and again on Sunday morning. Elsewhere, light rainfall
and cool temperatures will be commonplace.

Sunday night through Tuesday night, high pressure will return to
the Northern Rockies. Dry and warm conditions will prevail during
this time. In fact, the warmest temperatures of the year are
likely on afternoon.

High pressure is expected to break down Wednesday through next
weekend, with a series of weak storm systems moving across the
Northern Rockies. There is little consistency among operational
forecast models concerning the amount of moisture to be present
and the timing of each surface front. The current forecast
reflects low confidence and closely resembles climatology.

&&

.AVIATION...Rain showers will continue to bring low visibility
and ceilings to KBTM through this afternoon. At around 25/0000z,
showers are expected to gradually taper off but showers could
linger around KBTM through most of this evening. Cooler air will
be moving in tonight and will cause rain to transition to light snow
at KBTM. KSMN will also continue to see low ceilings and rain
showers through this evening. Another round of precipitation
develops late Saturday and will once again be focused over KBTM
and KSMN. This system looks to be stronger than the current one,
thus lower ceilings and visibilities should be expected Saturday
evening through Sunday.

&&

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

$$




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