150 
FXUS65 KTFX 100549
AFDTFX

Area Forecast Discussion
National Weather Service Great Falls MT
1049 PM MST Thu Feb 9 2017

.UPDATE...

Reports are starting to filter in from the Helena area of water 
pooling on ice covered roads resulting in extremely slick 
conditions. Updated the Flood Advisory Statement to include this 
new information. From the Helena Valley and south...everyone 
should be extremely cautious of localized flooding tonight through
Friday...as temperatures across most areas are not expected to 
get below freezing. Do not drive through flooded roads...and watch
out for ice under any ponding water.

Updated Aviation Discussion. 

&&

.AVIATION...
Updated 0600Z.

Moisture continues to stream into the area...with a weak frontal
boundary causing some scattered rain showers. Best chances for
these rain showers will occur from KHLN to KGTF and south into the
early overnight hours. Mountain rain and snow showers are also 
possible through the night...causing mountain obscuration.
Meanwhile mainly cloudy skies with breezy to strong winds will be
found for most other site. Low level wind shear is also possible
for most site. Rain and snow showers are then expected to be
mainly confined to the mountains for Friday...with mountain
obscuration again expected. Meanwhile...strong winds are expected
to develop from KCTB to KGTF and east to KLWT. Some with gusts
over 40 knots are possible. Winds may then diminish slightly late
in the period. Anglin 

&&

.PREV DISCUSSION...
/ISSUED 957 PM MST Thu Feb 9 2017/
FXUS65 KTFX 100457
AFDTFX

UPDATE...

957 pm update... Have included Fergus County in the High Wind 
Warning as gusts have reached 60 mph there in the last hour or so.
This is just ahead of a 700-mb frontal boundary that is currently
located from near Havre to Great Falls to just southeast of 
Missoula at this time. This front and the front of a low-level jet
are the primary contributors to the higher winds currently 
occurring in parts of Judith Basin and Fergus counties. Expect 
winds to diminish some after midnight with passage of this front. 
A brief period of light rainfall may also occur just as the front 
passes. Cassell

857 pm update...
Minor update this evening and overnight were to 
increase PoPs over central and far southern areas with current 
disturbance moving across the region. Also adjusted low 
temperatures down in the far northeast sections from Havre north 
and east where temperatures remain in the upper teens as much 
colder air has remained entrenched in the river valleys there. 
However, we do still expect temperatures there to rise overnight 
to as high as the 30s by morning, though confidence is low to 
medium at this point.

With such high snow levels and very warm temperatures across most
of southwestern Montana, we have started to receive reports of
ponding water across some roadways, particularly toward Gallatin
County. With temperatures expected to remain above freezing all
night with areas of rain and significant snowmelt occurring, we 
have issued a Flood Advisory for much of southwestern Montana 
through mid-morning Friday. Cassell

/ISSUED 252 PM MST Thu Feb 9 2017/

Tonight through Saturday...A broad upper level ridge axis positioned
roughly over the Rocky Mountains will continue to flatten tonight
and Friday. Two minor Clipper systems moving through this
increasing westerly flow will produce closed surface lows over
southern Alberta. The first has already developed and is dragging
a warm front across the region. Temperatures rose rapidly today
with the frontal passage. Colder locations remaining along the
Hi-line and in the central Helena valley are expected to mix out
this evening with rising temperatures overnight. Curiously, frost
has caused slippery roads where the relatively mild and moist air
has condensed on the sub freezing road surface. A winter weather
advisory remains in effect through early evening for this area to
allow for light icing potential, and possibly drifting snow before
warmer air arrives. High winds developed today for at least 
isolated locations along and west of Interstate 15. Winds should 
decline a bit overnight as the first surface low moves away. Winds
increase again Friday afternoon as the second Clipper arrives and
moves away, so high wind warnings will remain in effect. 
Anticipated severe drifting and blowing snow along the Rocky 
Mountain front did not materialize today as mild temperatures and 
rain stabilized the snow pack. Hence, the blizzard warning in 
effect for this area was cancelled and replaced by the high wind 
warning. Drifting and blowing snow remains possible for high 
elevation backcountry areas where temperatures remain below 
freezing. Temperatures turn a few degrees cooler Saturday as the 
second Clipper drags a weak cold front through the area. Overall 
temperatures remain near to above average through the weekend into
next week. Snowmelt could produce standing water in areas of poor
drainage or where the drains are plugged with snow. PN

Saturday Night through Thursday...Medium range models are in good 
agreement late this weekend through much of next week, depicting a 
longwave upper level ridge becoming established along or just inland 
of the west coast with dry conditions prevailing through at least 
Thursday under a northwest flow aloft. Weak upper level disturbances 
occasionally move over the top of the ridge, bringing periods of 
cloudiness and enhanced breezy winds over portions of north central 
MT at times Sunday and Monday with generally sunny conditions 
prevailing Tuesday through Thursday. Temperatures will start near 
seasonal averages on Sunday and gradually warm to above seasonal 
averages by the middle of next week. Hoenisch

&&

.PRELIMINARY POINT TEMPS/POPS...
GTF  38  47  29  37 /  20  10  10  10 
CTB  34  44  28  36 /  20   0  10  10 
HLN  36  38  19  30 /  40  20  20  10 
BZN  40  40  21  31 /  20  20  30  20 
WEY  35  35  17  25 /  90  80  40  40 
DLN  40  43  23  32 /  40  10  20  20 
HVR  19  44  29  37 /  10   0   0  10 
LWT  39  46  25  33 /  10  10  10  10 

&&

.TFX WATCHES/WARNINGS/ADVISORIES...
High Wind Warning until midnight MST Friday night Cascade...
Eastern Pondera...Eastern Teton...Fergus...Judith Basin...Toole.

High Wind Warning until midnight MST Friday night Eastern 
Glacier...Northern Rocky Mountain Front...Southern Rocky 
Mountain Front.

&&

$$

weather.gov/greatfalls

806 
FXUS65 KTFX 100609
AFDTFX

Area Forecast Discussion
National Weather Service Great Falls MT
1049 PM MST Thu Feb 9 2017

.UPDATE...

Reports are starting to filter in from the Helena area of water 
pooling on ice covered roads resulting in extremely slick 
conditions. Updated the Flood Advisory Statement to include this 
new information. From the Helena Valley and south...everyone 
should be extremely cautious of localized flooding tonight through
Friday...as temperatures across most areas are not expected to 
get below freezing. Do not drive through flooded roads...and watch
out for ice under any ponding water.

Updated Aviation Discussion. 

&&

.AVIATION...
Updated 0600Z.

Moisture continues to stream into the area...with a weak frontal
boundary causing some scattered rain showers. Best chances for
these rain showers will occur from KHLN to KGTF and south into the
early overnight hours. Mountain rain and snow showers are also 
possible through the night...causing mountain obscuration.
Meanwhile mainly cloudy skies with breezy to strong winds will be
found for most other site. Low level wind shear is also possible
for most site. Rain and snow showers are then expected to be
mainly confined to the mountains for Friday...with mountain
obscuration again expected. Meanwhile...strong winds are expected
to develop from KCTB to KGTF and east to KLWT. Some with gusts
over 40 knots are possible. Winds may then diminish slightly late
in the period. Anglin 

&&

.PREV DISCUSSION...
/ISSUED 957 PM MST Thu Feb 9 2017/
FXUS65 KTFX 100457
AFDTFX

UPDATE...

957 pm update... Have included Fergus County in the High Wind 
Warning as gusts have reached 60 mph there in the last hour or so.
This is just ahead of a 700-mb frontal boundary that is currently
located from near Havre to Great Falls to just southeast of 
Missoula at this time. This front and the front of a low-level jet
are the primary contributors to the higher winds currently 
occurring in parts of Judith Basin and Fergus counties. Expect 
winds to diminish some after midnight with passage of this front. 
A brief period of light rainfall may also occur just as the front 
passes. Cassell

857 pm update...
Minor update this evening and overnight were to 
increase PoPs over central and far southern areas with current 
disturbance moving across the region. Also adjusted low 
temperatures down in the far northeast sections from Havre north 
and east where temperatures remain in the upper teens as much 
colder air has remained entrenched in the river valleys there. 
However, we do still expect temperatures there to rise overnight 
to as high as the 30s by morning, though confidence is low to 
medium at this point.

With such high snow levels and very warm temperatures across most
of southwestern Montana, we have started to receive reports of
ponding water across some roadways, particularly toward Gallatin
County. With temperatures expected to remain above freezing all
night with areas of rain and significant snowmelt occurring, we 
have issued a Flood Advisory for much of southwestern Montana 
through mid-morning Friday. Cassell

/ISSUED 252 PM MST Thu Feb 9 2017/

Tonight through Saturday...A broad upper level ridge axis positioned
roughly over the Rocky Mountains will continue to flatten tonight
and Friday. Two minor Clipper systems moving through this
increasing westerly flow will produce closed surface lows over
southern Alberta. The first has already developed and is dragging
a warm front across the region. Temperatures rose rapidly today
with the frontal passage. Colder locations remaining along the
Hi-line and in the central Helena valley are expected to mix out
this evening with rising temperatures overnight. Curiously, frost
has caused slippery roads where the relatively mild and moist air
has condensed on the sub freezing road surface. A winter weather
advisory remains in effect through early evening for this area to
allow for light icing potential, and possibly drifting snow before
warmer air arrives. High winds developed today for at least 
isolated locations along and west of Interstate 15. Winds should 
decline a bit overnight as the first surface low moves away. Winds
increase again Friday afternoon as the second Clipper arrives and
moves away, so high wind warnings will remain in effect. 
Anticipated severe drifting and blowing snow along the Rocky 
Mountain front did not materialize today as mild temperatures and 
rain stabilized the snow pack. Hence, the blizzard warning in 
effect for this area was cancelled and replaced by the high wind 
warning. Drifting and blowing snow remains possible for high 
elevation backcountry areas where temperatures remain below 
freezing. Temperatures turn a few degrees cooler Saturday as the 
second Clipper drags a weak cold front through the area. Overall 
temperatures remain near to above average through the weekend into
next week. Snowmelt could produce standing water in areas of poor
drainage or where the drains are plugged with snow. PN

Saturday Night through Thursday...Medium range models are in good 
agreement late this weekend through much of next week, depicting a 
longwave upper level ridge becoming established along or just inland 
of the west coast with dry conditions prevailing through at least 
Thursday under a northwest flow aloft. Weak upper level disturbances 
occasionally move over the top of the ridge, bringing periods of 
cloudiness and enhanced breezy winds over portions of north central 
MT at times Sunday and Monday with generally sunny conditions 
prevailing Tuesday through Thursday. Temperatures will start near 
seasonal averages on Sunday and gradually warm to above seasonal 
averages by the middle of next week. Hoenisch

&&

.PRELIMINARY POINT TEMPS/POPS...
GTF  38  47  29  37 /  20  10  10  10 
CTB  34  44  28  36 /  20   0  10  10 
HLN  36  38  19  30 /  40  20  20  10 
BZN  40  40  21  31 /  20  20  30  20 
WEY  35  35  17  25 /  90  80  40  40 
DLN  40  43  23  32 /  40  10  20  20 
HVR  19  44  29  37 /  10   0   0  10 
LWT  39  46  25  33 /  10  10  10  10 

&&

.TFX WATCHES/WARNINGS/ADVISORIES...
High Wind Warning until midnight MST Friday night Cascade...
Eastern Pondera...Eastern Teton...Fergus...Judith Basin...Toole.

High Wind Warning until midnight MST Friday night Eastern 
Glacier...Northern Rocky Mountain Front...Southern Rocky 
Mountain Front.

Flood Advisory for Lewis and Clark...Central Pondera...Glacier... 
Toole...Teton...West central Cascade Counties until 0800 am MST. 

Flood Advisory for Southern Lewie and 
Clark...Broadwater...Meagher...southwestern Judith 
Basin...Madison...Southeastern Beaverhead...Jefferson...Gallatin 
Counties until 0730 am MST Friday. 

&&

$$

weather.gov/greatfalls