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000
FXUS65 KMSO 232027
AFDMSO

Area Forecast Discussion
National Weather Service Missoula MT
227 PM MDT Wed Apr 23 2014

.DISCUSSION...Very unstable conditions have led to numerous rain
and snow showers across north-central Idaho into western Montana
this afternoon. There was a report of snow mixed with graupel in
Columbia Falls earlier, so graupel couldn`t be ruled out. Lookout
Pass has been receiving snow showers all day, but road surfaces
are warm so the only impact would be periodic reductions in
visibility and slush. An influx of slightly stronger winds in the
mid-level region of the atmosphere will move through southwest
Montana this afternoon and early evening. This will bring the
potential for gusty winds between 30 to 40 mph especially along
the I-90 corridor from Garrison Junction to Butte, along State
Highway 141 north of Avon and at MacDonald Pass on US-2. Have
introduced the chance for patchy fog in a few valleys of northwest
Montana. There could be just enough thinning of the clouds to
allow for some fog or stratus to develop, but confidence is low.

An upper level ridge moves through Thursday morning, but will not
bring quiet weather. There will be an above normal chance for
precipitation due to an influx of Pacific moisture moving through
this ridge. The best timing for widespread rainfall across central
Idaho will be Thursday morning as the leading upper level wave
moves through. Continued showers are expected through much of
Thursday. A possible break in precipitation across northwest
Montana will be possible by Thursday night ahead of the next
weather system. Have lowered the chance for precipitation there,
but have continued higher precipitation chances across central
Idaho. Normal high temperatures this time of year across western
Montana range from the mid-50`s to the lower 60`s. Missoula and
Kalispell are around 60 degrees while Butte is around 55 degrees.
Thursday highs will come in just under those readings.

Another trough will pass through the region Friday through the
weekend. There are similarities between the upcoming weather
system and the one that recently passed with moisture to arrive
from the south and cold fronts to bring wind and lower snow
levels. Multiple shortwaves within the main trough will again
create chances for mountain pass snow and periods of slick
conditions across Lemhi County and along the Continental Divide
Friday night and on Saturday night.

There are still indications that high pressure will begin to
develop early next week and last into midweek. Uncertainties
remain on the placement and strength of the upper level ridge but
a warming trend with decreased chances for precipitation is
looking more likely.

&&

.AVIATION...Rain and snow showers will continue through this
afternoon. Gusty winds will also remain in association with a
passing shortwave. Brief reductions in visibilities and ceilings
are possible under stronger showers especially at KGPI and KBTM.
Showers and wind will decrease this evening as a weak ridge
moves into the region. North central Idaho will have little if any
break in cloud cover and rain as the next warm front moves over tonight.
Western Montana on the other hand may have isolated areas of
clearing that in conjuncture with afternoon showers will lead to a
chance for fog Thursday morning. Any patchy fog that does develop
will be short-lived. Showers and cloud cover will increase from
the southwest on Thursday with the passage of the warm front.

&&

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

$$

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000
FXUS65 KMSO 230914
AFDMSO

Area Forecast Discussion
National Weather Service Missoula MT
314 AM MDT Wed Apr 23 2014

.DISCUSSION...The area has transitioned to a much colder air mass
for today, however it remains unstable. As a result rain and snow
showers are expected again today. Due to the warm ground and
strength of the late April sun, no accumulation is expected except
in the mountains today. A few lightning strikes are possible with
deeper convection, but not expected since the freezing level is so
low and surface temperatures are so cold. The biggest impact
from the showers will probably be winds. With 20-25 mph winds in
the area, any additional winds from showers may enhance them
causing gusts near 40 mph. The situation will be similar Thursday,
though winds will be lesser than today.

Thursday Night through Sunday...A moist and unstable atmosphere
will persist through the weekend as a large-scale trough of low
pressure slowly migrates through the western states. The air mass
will be cool enough for additional snow in the mountains, while
valley locations will precipitation fall as rain.

Monday through Tuesday...Medium range models continue to show a
ridge of high pressure developing over the inter-mountain west.
Forecast confidence is growing for prospects of a warmer, dry
period for early next week.

&&

.AVIATION...Showers continue today, with snow showers causing
frequent mountain obscurations. With decent northwesterly flow
aloft and good instability due to the late April sun and a cold
air mass, expect a lot of quick moving showers and constantly
changing conditions, especially at KMSO and KBTM.

&&

.MSO WATCHES/WARNINGS/ADVISORIES...
MT...WINTER WEATHER ADVISORY until 9 AM MDT this morning
     Bitterroot/Sapphire Mountains...Butte/Blackfoot Region.

ID...None.
&&

$$

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000
FXUS65 KMSO 230057 AAA
AFDMSO

Area Forecast Discussion...UPDATED
National Weather Service Missoula MT
657 PM MDT Tue Apr 22 2014

.UPDATE...Allowed the wind advisory for portions of SW Montana to expire.


&&

.DISCUSSION...The threat for strong winds from convective activity has
lessened enough to allow the wind advisory for portions of
southwest Montana to expire. However, breezy winds do exist
currently across central Idaho and western Montana, and will
continue through the night into Wednesday morning. At this time,
they are not expected to be very strong, although intermittent
gusts are likely.


&&

.AVIATION...A cold front will shift east of the Divide by late
this afternoon. Along this front, rather strong and gusty winds
and isolated thunderstorms will continue across southwest Montana.
Considering some of the the stronger and isolated convection, wind
gusts to 50 mph are possible. A larger area of light to moderate
precipitation is behind the cold front and will shift from the
Clearwaters and Bitterroots across southwest Montana this evening.
Widespread mountain obscuration, and lower ceilings and
visibilities will accompany this precipitation area. Also, areas
of light to moderate rain should change to snow in the higher
valleys as colder air surges into the region. The KMSO and KSMN
TAF sites should be impact first this afternoon into early
evening. KBTM will see the lower ceilings/visibilities and rain
changing to snow this evening.


&&

.PREV DISCUSSION... /ISSUED 203 PM MDT Tue Apr 22 2014/

..STRONG WINDS ACROSS SOUTHWEST MONTANA THROUGH THIS EVENING...
..LIGHT SNOW OVER MOUNTAIN PASSES THIS EVENING THROUGH WEDNESDAY...

DISCUSSION...An unstable atmosphere and favorable low level wind
profile will support locally strong showers and isolated
thunderstorms across southwest Montana and Lemhi County until 4 or
5 p.m. this afternoon. A cold front will also move across
southwest Montana during the mid to late afternoon producing
strong gusty winds as well. Thereafter, the wind threat will shift
east of the Continental Divide.

The second impact of concern is a colder air mass combining with
additional moisture surging across the Bitterroots, Sapphires, and
Georgetown Lake to Butte area this evening. Snow levels will
rapidly lower to high valley floors (such as Georgetown lake,
Anaconda, Butte) with some accumulation likely, especially above
5500 feet. However, road surfaces should remain warm enough
through the evening to keep most road accumulations to just patchy
slush. However, Lost Trail Pass and Bannock Pass may become more
snow packed through the evening and night.

The third impact is a very cold northwest flow and additional
surge of moisture moving across Grangeville and Orofino and mainly
eastward to the Bitterroots and Sapphire Mountains of western
Montana Wednesday. The strong winds aloft should help produce
more banded showers, but also gusty winds. This cold and more banded
type showers Wednesday should produce snow accumulations on area
mountain passes, especially Lolo and Lost Trail Passes. However,
given the more concentrated snow should be during the mid day and
afternoon, roads should remain wet because of day time heating.

Additional Pacific weather systems and a southwest flow is
expected Thursday into Saturday. A fair amount of moisture will
occasionally push across the region. Valley temperatures should
moderate some Thursday and Friday, but the air mass remain cold
enough for additional mountain snow. As such, only modest stream
rises are expected into the weekend.

In the longer term, model guidance is showing a warmer weather
pattern (associated with a ridge of high pressure) developing early
next week. Due to model to model and run to run inconsistencies
regarding the timing and strength of the this warmer weather
pattern, confidence is still rather low.


&&

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

$$

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000
FXUS65 KMSO 222003
AFDMSO

Area Forecast Discussion
National Weather Service Missoula MT
203 PM MDT Tue Apr 22 2014

...STRONG WINDS ACROSS SOUTHWEST MONTANA THROUGH THIS EVENING...
...LIGHT SNOW OVER MOUNTAIN PASSES THIS EVENING THROUGH WEDNESDAY...

.DISCUSSION...An unstable atmosphere and favorable low level wind
profile will support locally strong showers and isolated
thunderstorms across southwest Montana and Lemhi County until 4 or
5 p.m. this afternoon. A cold front will also move across
southwest Montana during the mid to late afternoon producing
strong gusty winds as well. Thereafter, the wind threat will shift
east of the Continental Divide.

The second impact of concern is a colder air mass combining with
additional moisture surging across the Bitterroots, Sapphires, and
Georgetown Lake to Butte area this evening. Snow levels will
rapidly lower to high valley floors (such as Georgetown lake,
Anaconda, Butte) with some accumulation likely, especially above
5500 feet. However, road surfaces should remain warm enough
through the evening to keep most road accumulations to just patchy
slush. However, Lost Trail Pass and Bannock Pass may become more
snow packed through the evening and night.

The third impact is a very cold northwest flow and additional
surge of moisture moving across Grangeville and Orofino and mainly
eastward to the Bitterroots and Sapphire Mountains of western
Montana Wednesday. The strong winds aloft should help produce
more banded showers, but also gusty winds. This cold and more banded
type showers Wednesday should produce snow accumulations on area
mountain passes, especially Lolo and Lost Trail Passes. However,
given the more concentrated snow should be during the mid day and
afternoon, roads should remain wet because of day time heating.

Additional Pacific weather systems and a southwest flow is
expected Thursday into Saturday. A fair amount of moisture will
occasionally push across the region. Valley temperatures should
moderate some Thursday and Friday, but the air mass remain cold
enough for additional mountain snow. As such, only modest stream
rises are expected into the weekend.

In the longer term, model guidance is showing a warmer weather
pattern (associated with a ridge of high pressure) developing early
next week. Due to model to model and run to run inconsistencies
regarding the timing and strength of the this warmer weather
pattern, confidence is still rather low.

&&

.AVIATION...A cold front will shift east of the Divide by late
this afternoon. Along this front, rather strong and gusty winds
and isolated thunderstorms will continue across southwest Montana.
Considering some of the the stronger and isolated convection, wind
gusts to 50 mph are possible. A larger area of light to moderate
precipitation is behind the cold front and will shift from the
Clearwaters and Bitterroots across southwest Montana this evening.
Widespread mountain obscuration, and lower ceilings and
visibilities will accompany this precipitation area. Also, areas
of light to moderate rain should change to snow in the higher
valleys as colder air surges into the region. The KMSO and KSMN
TAF sites should be impact first this afternoon into early
evening. KBTM will see the lower ceilings/visibilities and rain
changing to snow this evening.

&&

.MSO WATCHES/WARNINGS/ADVISORIES...
MT...WIND ADVISORY until 6 PM MDT this evening Butte/Blackfoot Region.

ID...None.
&&

$$

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000
FXUS65 KMSO 221440
AFDMSO

Area Forecast Discussion
National Weather Service Missoula MT
840 AM MDT Tue Apr 22 2014

.UPDATE...Updated forecast today to add more wind from about
Missoula to Kalispell and eastward to Divide as the cold front
shifts east across area mid day and this afternoon. Also, may see
isolated strong thunderstorms/convection from the Sapphire
Mountains eastward to Deerlodge, Anaconda, and Butte this
afternoon.


&&

.DISCUSSION...A cold front should plow into western Montana later
this morning and then further intensify as it shifts across
southwest Montana this afternoon. Strong gusty west to northwest
winds are expected as the front passes. The bigger short term
concern is possible strong convection and isolated thunderstorms
across southwest Montana this afternoon. The stronger showers
could produce wind gusts to possibly 50 mph. Brief moderate to
heavy rain should also accompany the convection with ponding along
roads a concern.


&&

.AVIATION...Increasing mid and low level clouds today as large
trough and cold front move into the northern Rockies. Frontal
passage is expected by mid day Missoula to Kalispell and this
afternoon across southwest Montana and along the Divide. Lowering
ceilings and visibilities can be expected as stronger showers and
isolated thunderstorms develop along the front. Also, brief
stronger winds gusts 40 to 50 mph are possible with the stronger
convection in southwest Montana this afternoon. Increasing
mountain obscurations, and a transition to snow showers can be
expected, especially across southwest Montana into early this
evening.

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



&&

.PREV DISCUSSION... /ISSUED 308 AM MDT Tue Apr 22 2014/

DISCUSSION...Several impacts today and Wednesday from a change in
the overall weather pattern ushered in by a cold front today.

First, the cold front will move across the region today, with most
of the action occurring this afternoon and evening. Expect a brief
period of increased winds as the front passes, otherwise it will
be breezy today. A recent change in the model forecasts has the
front intensifying over the Continental Divide this afternoon and
evening. As a result, Georgetown, Anaconda, Deer Lodge, and Butte
could see half an inch or more of rain and some snow by Wednesday
morning, with higher amounts in the mountains. There is also a
slight chance of thunderstorms along the Continental Divide late
this afternoon and this evening.

Most of the precipitation is expected to fall as rain, but there
is considerable uncertainty in the snow levels, especially with
the heavier precipitation. The main area of concern is again
Georgetown to Butte. This area will be monitored closely for a
potential winter weather advisory. Ground temperatures are very
warm right now, with sub-surface temperatures over 50 degrees in
many places. As a result, significant snow accumulation on roads
is not expected except in areas of heavy snow. Otherwise, expect
snow on elevated surfaces and the grass.

Most mountain passes are also expected to get some snow. While
snow levels are now very high, it will start as rain today and
turn to snow around midnight. Accumulations on the roads are
uncertain due to the very warm ground temperatures. If it does
accumulate it will be very slushy on the roads under the heaviest
showers.

Wednesday showers will continue, but the dominant impact will be
the wind. Again the biggest impacts will be from Georgetown to
Butte and along the Continental Divide with 20 mph winds gusting
near 40 mph regularly in the afternoon.

Thursday through Sunday...The active weather pattern will continue
as the models are now favoring a broad scale trough of low
pressure over the Northern Rockies region. In fact, this pattern
is beginning to look very similar to the weather pattern expected
during the next couple of days (today and Wednesday). This deep
trough will be able to tap into some sub-tropical moisture and
transport it northward into the region. Thus, we have increased
the chances of precipitation. Temperatures will be running a few
degrees cooler than normal thanks to cloud cover and potential for
precipitation.

Monday through Tuesday...Latest runs of the medium range forecast
models have been hinting at a ridge building into the region. If
models remain consistent with this pattern change, we will return
to warmer, dry conditions.

AVIATION...Increasing mid and low level clouds today as large
trough and cold front move into the northern Rockies. Frontal
passage is expected this afternoon and evening with lowering
ceilings, increasing mountain obscurations, and a rain-snow mix.

&&

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

$$

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000
FXUS65 KMSO 220908
AFDMSO

Area Forecast Discussion
National Weather Service Missoula MT
308 AM MDT Tue Apr 22 2014

.DISCUSSION...Several impacts today and Wednesday from a change in
the overall weather pattern ushered in by a cold front today.

First, the cold front will move across the region today, with most
of the action occurring this afternoon and evening. Expect a brief
period of increased winds as the front passes, otherwise it will
be breezy today. A recent change in the model forecasts has the
front intensifying over the Continental Divide this afternoon and
evening. As a result, Georgetown, Anaconda, Deer Lodge, and Butte
could see half an inch or more of rain and some snow by Wednesday
morning, with higher amounts in the mountains. There is also a
slight chance of thunderstorms along the Continental Divide late
this afternoon and this evening.

Most of the precipitation is expected to fall as rain, but there
is considerable uncertainty in the snow levels, especially with
the heavier precipitation. The main area of concern is again
Georgetown to Butte. This area will be monitored closely for a
potential winter weather advisory. Ground temperatures are very
warm right now, with sub-surface temperatures over 50 degrees in
many places. As a result, significant snow accumulation on roads
is not expected except in areas of heavy snow. Otherwise, expect
snow on elevated surfaces and the grass.

Most mountain passes are also expected to get some snow. While
snow levels are now very high, it will start as rain today and
turn to snow around midnight. Accumulations on the roads are
uncertain due to the very warm ground temperatures. If it does
accumulate it will be very slushy on the roads under the heaviest
showers.

Wednesday showers will continue, but the dominant impact will be
the wind. Again the biggest impacts will be from Georgetown to
Butte and along the Continental Divide with 20 mph winds gusting
near 40 mph regularly in the afternoon.

Thursday through Sunday...The active weather pattern will continue
as the models are now favoring a broad scale trough of low
pressure over the Northern Rockies region. In fact, this pattern
is beginning to look very similar to the weather pattern expected
during the next couple of days (today and Wednesday). This deep
trough will be able to tap into some sub-tropical moisture and
transport it northward into the region. Thus, we have increased
the chances of precipitation. Temperatures will be running a few
degrees cooler than normal thanks to cloud cover and potential for
precipitation.

Monday through Tuesday...Latest runs of the medium range forecast
models have been hinting at a ridge building into the region. If
models remain consistent with this pattern change, we will return
to warmer, dry conditions.


&&

.AVIATION...Increasing mid and low level clouds today as large
trough and cold front move into the northern Rockies. Frontal
passage is expected this afternoon and evening with lowering
ceilings, increasing mountain obscurations, and a rain-snow mix.

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


&&

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

$$

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000
FXUS65 KMSO 212033
AFDMSO

Area Forecast Discussion
National Weather Service Missoula MT
233 PM MDT Mon Apr 21 2014

...Significant Spring Storm for Tuesday and Wednesday...

.DISCUSSION...Dry conditions will persist through tonight, but mid
to high level clouds will be on the increase. A strong and moist
cold front will swing through the Northern Rockies on Tuesday.
This front will cause moderate to heavy precipitation, with snow
in the mountains and rain in the valleys. The combination of snow
melt from today with the rainfall tomorrow could cause significant
rises in small streams and creeks. Even though snow will be
falling at the mountain passes during the day on Tuesday,
accumulations on the roads should be minimal. Widespread showers
will linger Tuesday night, and once the sun sets, snow could start
impacting the passes. Snow levels could drop low enough that the
Flathead valley south to the Bitterroot valley could even see some
snow (but is not anticipated to accumulate). By Wednesday
afternoon, showers will be on the increase with gusty westerly
winds mixing to the surface. The I-90 corridor from Deer Lodge to
Anaconda, Helmville to Avon, and passes over the Continental Divide
should experience the strongest wind gusts. Temperatures for
Wednesday will only reach into the 30s and 40s, which is a big
change from the 60s and 70s experienced today.

North central Idaho and western Montana will remain under an
active weather pattern from Thursday through the weekend. A
general trough pattern over the Pacific Northwest will leave
chances for precipitation above normal and temperatures slightly
blow normal during this period. Moderate rain and high elevation
snow are going to occur from time to time, but any focused period
is a bit tough to isolate at this time. Model guidance do
agree on the general moist and cooler pattern, but the finer
details still need some working out.

&&

.AVIATION...As the ridge of high pressure will continue to shift into
eastern Montana this evening, high and mid levels clouds will be
on the increase from the southwest. Overall, weather conditions
will be favorable for aviation operations through tonight. The
cold front is anticipated to move into north central Idaho during
the morning hours on Tuesday, then push through western Montana on
Tuesday afternoon.

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

$$

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000
FXUS65 KMSO 210908
AFDMSO

Area Forecast Discussion
National Weather Service Missoula MT
308 AM MDT Mon Apr 21 2014

.DISCUSSION...
Today and Tonight...The upper ridge of high pressure will shift
east of the Continental Divide with a southwesterly flow
developing over the Northern Rockies. High clouds will be
increasing and thickening up today for some filtered sunshine.

Tuesday morning will be warm with strong southerly flow ahead of
an approaching cold front. The cold front arrives Tuesday
afternoon causing significant precipitation in the mountains and
valleys with snow above 7,000 feet for most of the day.

Overnight the snow levels will drop by about 4,000 feet, allowing
at least a rain snow mix by Wednesday morning in most of the
valleys. Models have trended lower with snow levels, so adjusted
them lower in the forecast. As a result, added less than half an
inch of snow in the Flathead, Mission, Bitterroot, and Missoula
valleys to the forecast. With the warm wet day before and low
temperatures near freezing, expect snow will mainly accumulate on
elevated surfaces and the grass with a lot of melting on the
roads. However, colder temperatures at slightly higher elevations
mean roads could get slick very quickly coming up out of the
valleys. Snow accumulations around six inches or less are expected
at many area passes.

Showers will continue Wednesday, however, forecast rain amounts
were lowered. Model trends have recently been pulling the low
pressure center farther north with this system. As a result,
western Montana doesn`t get much of the wrap-around moisture on
the north side of the low. Also raised winds Wednesday, especially
along the Continental Divide, due to the position of the low and
model trends. Wind gusts Wednesday afternoon will consistently be
around 35 mph in the Butte-Anaconda area. Stronger winds are
possible in the vicinity of showers. Overall Wednesday will be a
cool and blustery day with temperatures in the 30s to low 40s,
high winds, and showers.

Thursday through Sunday...A active weather pattern is still being
advertised by the medium range models through this period. While
the models agree mostly with the large scale pattern, they still
differ significantly with respect to placement and timing of
precipitation.


&&

.AVIATION...As the ridge of high pressure shifts into eastern
Montana today, look for increasing high clouds from the
southwest. Overall, weather conditions will be favorable for
aviation operations today. Clouds will be thickening and bases
slowly lowering overnight tonight mainly over the Idaho Panhandle
and northwest Montana.


&&

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

$$

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