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000
FXUS65 KTFX 180542
AFDTFX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREAT FALLS MT
1035 PM MST Wed Dec 17 2014

Aviation Section Updated.

.UPDATE...
Latest observations show freezing fog, dense in areas, continuing
over most of the Hiline counties and redeveloping in parts of
Pondera and Teton counties. So have extended the freezing fog
advisory for eastern Glacier and Toole and added eastern Pondera,
Teton, Liberty, and Hill counties to the advisory that now goes
until 9am Thurs. Also adjusted the overnight lows in the fog areas
as several sites were at/below the forecast minimum temps. A weak
shortwave trof currently crossing western MT may help increase the
surface winds east of the Divide during the overnight hours to
help dissipate some of the fog, but confidence is only marginal
for that to occur.
Waranauskas

&&

.AVIATION...
UPDATED 0535Z.
Persistent freezing fog has started to erode at KCTB with downslope
mixing, transitioning to VFR conditions. Dense freezing fog has
developed further east along the highline including KHVR. Expect
this to continue with LIFR conditions through early morning. Patchy
fog is periodically moving across the airfield at KHLN, yielding
flight category changes on the order of tens of minutes. Otherwise,
VFR conditions prevail through the period under generally clear
skies. High cloud cover will increase Thursday as another weak
disturbance moves into western Montana. Nutter

&&

.PREV DISCUSSION...
/ISSUED 435 PM MST Wed Dec 17 2014/
Wednesday night through Friday...A rather quiet and cool end to
the work week is expected as no major systems are expected to move
over the area in this time frame. Temperatures will remain near
seasonal values as weak shortwave toughing on Thursday will be
followed by a week shortwave ridge on Friday. The biggest impact
during this time period will be the persistent freezing fog over
parts of Central and North Central Montana. Have extended the
advisory currently in effect until 9 pm for areas around Cut Bank
and Shelby. Westerly winds should develop around 6 pm and
eventual scour out the fog. However, there is a chance that the
nocturnal boundary layer will strengthen the inversion and will
limit any potential for the west winds to move the fog out of the
area until Thursday when a weak shortwave moves through the area.
Widespread moisture is not expected at this time with this
disturbance...however some isolated mountain snow showers are
possible. Suk

Friday Night through Wednesday...A weak shortwave trough will move
through Montana Friday night into Saturday, bringing just a chance
of snow to the mountains. Forecast models continue to indicate
that the pattern will then change for Saturday night through
Tuesday. An upper level high pressure ridge will strengthen off
the California coast and a low pressure trough will deepen from
Hudson Bay into the Great Lakes. This will result in Montana being
under a strong northwesterly flow aloft. The models indicate that
the strongest winds aloft will occur Sunday into Sunday night with
the passage of a disturbance embedded in the flow. However, the
models differ on just how strong these winds will be. The ECMWF
only forecasts winds of 45 to 55 kts at 700 mb, while the GFS
generally has 60 to 70 kt winds. Have therefore used a compromise
solution between these two models with regards to surface wind
strength. Despite this difference, this set-up will bring gusty
westerly downslope winds to much of the area, but especially over
the plains of north central Montana. In fact, some areas along the
Rocky Mountain Front could approach High Wind criteria (40 mph
sustained/58 mph gusts). Confidence remains moderate that High
Wind highlights may be needed for this event. The only concern is
that the northwesterly wind direction is not as favorable for
widespread High Winds. There is also significant moisture with
this disturbance, so have continued to spread the chance for
precipitation out onto the plains. Winds aloft will decrease
somewhat after the passage of the disturbance, but the
northwesterly flow aloft will remain fairly moist, so have kept
the chance for precipitation above climatological normals across
the area into Tuesday. A potentially significant weather system
originating in the Gulf of Alaska is then forecast to move into
Montana Tuesday into Wednesday, bringing a very good chance of
precipitation. Because this feature is near the end of the period,
exact timing and types of precipitation are very uncertain.
Regardless, this system will need to be monitored for potential
winter weather highlights, especially considering that it would be
moving into the area during peak holiday travel time. The breezy
winds through Monday will keep temperatures around 10 degrees
above normal. The warmest day of the period appears to be Monday,
when most lower elevation locations should get well into the 40s.
However, with the system moving into the area at the end of the
period, temperatures will likely fall back to near or slightly
below seasonal averages by Wednesday. Coulston

&&

.PRELIMINARY POINT TEMPS/POPS...
GTF  25  40  26  40 /  10  10  10  10
CTB  12  39  24  39 /  10  10  10  10
HLN  19  34  19  35 /  10  20  10  20
BZN  14  30  15  32 /  10  10  10  20
WEY  17  32  19  33 /  20  20  30  40
DLN  18  34  19  37 /  10  20  10  20
HVR  16  37  22  39 /  10  10  10  10
LWT  23  43  24  43 /  10  10  10  10

&&

.TFX WATCHES/WARNINGS/ADVISORIES...
FREEZING FOG ADVISORY until 9 AM MST Thursday Eastern Glacier...
Eastern Pondera...Eastern Teton...Hill...Liberty...Southern
Rocky Mountain Front...Toole.

&&

$$

weather.gov/greatfalls
www.twitter.com/NWSGreatFalls
www.facebook.com/NWSGreatFalls







000
FXUS65 KTFX 180443
AFDTFX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREAT FALLS MT
943 PM MST Wed Dec 17 2014

.UPDATE...
Latest observations show freezing fog, dense in areas, continuing
over most of the Hiline counties and redeveloping in parts of
Pondera and Teton counties. So have extended the freezing fog
advisory for eastern Glacier and Toole and added eastern Pondera,
Teton, Liberty, and Hill counties to the advisory that now goes
until 9am Thurs. Also adjusted the overnight lows in the fog areas
as several sites were at/below the forecast minimum temps. A weak
shortwave trof currently crossing western MT may help increase the
surface winds east of the Divide during the overnight hours to
help dissipate some of the fog, but confidence is only marginal
for that to occur.
Waranauskas

&&

.AVIATION...
UPDATED 2335Z.
Persistent freezing fog continues at KCTB with LIFR conditions.
Southwesterly downslope flow is expected to erode this area of fog
through the evening hours. Confidence in the timing of fog clearing
is low. Short-term guidance indicates that fog could return to KHVR,
but confidence is low and so did not include in TAF. Elsewhere,
skies are clearing this evening behind a departing weather system.
High cloud cover will increase by morning as another weak
disturbance moves into western Montana. Conditions will remain VFR
at all terminals except KCTB and possibly KHVR as highlighted above.
Nutter

&&

.PREV DISCUSSION...
/ISSUED 435 PM MST Wed Dec 17 2014/
Wednesday night through Friday...A rather quiet and cool end to
the work week is expected as no major systems are expected to move
over the area in this time frame. Temperatures will remain near
seasonal values as weak shortwave toughing on Thursday will be
followed by a week shortwave ridge on Friday. The biggest impact
during this time period will be the persistent freezing fog over
parts of Central and North Central Montana. Have extended the
advisory currently in effect until 9 pm for areas around Cut Bank
and Shelby. Westerly winds should develop around 6 pm and
eventual scour out the fog. However, there is a chance that the
nocturnal boundary layer will strengthen the inversion and will
limit any potential for the west winds to move the fog out of the
area until Thursday when a weak shortwave moves through the area.
Widespread moisture is not expected at this time with this
disturbance...however some isolated mountain snow showers are
possible. Suk

Friday Night through Wednesday...A weak shortwave trough will move
through Montana Friday night into Saturday, bringing just a chance
of snow to the mountains. Forecast models continue to indicate
that the pattern will then change for Saturday night through
Tuesday. An upper level high pressure ridge will strengthen off
the California coast and a low pressure trough will deepen from
Hudson Bay into the Great Lakes. This will result in Montana being
under a strong northwesterly flow aloft. The models indicate that
the strongest winds aloft will occur Sunday into Sunday night with
the passage of a disturbance embedded in the flow. However, the
models differ on just how strong these winds will be. The ECMWF
only forecasts winds of 45 to 55 kts at 700 mb, while the GFS
generally has 60 to 70 kt winds. Have therefore used a compromise
solution between these two models with regards to surface wind
strength. Despite this difference, this set-up will bring gusty
westerly downslope winds to much of the area, but especially over
the plains of north central Montana. In fact, some areas along the
Rocky Mountain Front could approach High Wind criteria (40 mph
sustained/58 mph gusts). Confidence remains moderate that High
Wind highlights may be needed for this event. The only concern is
that the northwesterly wind direction is not as favorable for
widespread High Winds. There is also significant moisture with
this disturbance, so have continued to spread the chance for
precipitation out onto the plains. Winds aloft will decrease
somewhat after the passage of the disturbance, but the
northwesterly flow aloft will remain fairly moist, so have kept
the chance for precipitation above climatological normals across
the area into Tuesday. A potentially significant weather system
originating in the Gulf of Alaska is then forecast to move into
Montana Tuesday into Wednesday, bringing a very good chance of
precipitation. Because this feature is near the end of the period,
exact timing and types of precipitation are very uncertain.
Regardless, this system will need to be monitored for potential
winter weather highlights, especially considering that it would be
moving into the area during peak holiday travel time. The breezy
winds through Monday will keep temperatures around 10 degrees
above normal. The warmest day of the period appears to be Monday,
when most lower elevation locations should get well into the 40s.
However, with the system moving into the area at the end of the
period, temperatures will likely fall back to near or slightly
below seasonal averages by Wednesday. Coulston

&&

.PRELIMINARY POINT TEMPS/POPS...
GTF  25  40  26  40 /  10  10  10  10
CTB  12  39  24  39 /  10  10  10  10
HLN  19  34  19  35 /  10  20  10  20
BZN  14  30  15  32 /  10  10  10  20
WEY  17  32  19  33 /  20  20  30  40
DLN  18  34  19  37 /  10  20  10  20
HVR  16  37  22  39 /  10  10  10  10
LWT  23  43  24  43 /  10  10  10  10

&&

.TFX WATCHES/WARNINGS/ADVISORIES...
FREEZING FOG ADVISORY until 9 AM MST Thursday Eastern Glacier...
Eastern Pondera...Eastern Teton...Hill...Liberty...Southern
Rocky Mountain Front...Toole.

&&

$$

weather.gov/greatfalls
www.twitter.com/NWSGreatFalls
www.facebook.com/NWSGreatFalls





000
FXUS65 KTFX 180443
AFDTFX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREAT FALLS MT
943 PM MST Wed Dec 17 2014

.UPDATE...
Latest observations show freezing fog, dense in areas, continuing
over most of the Hiline counties and redeveloping in parts of
Pondera and Teton counties. So have extended the freezing fog
advisory for eastern Glacier and Toole and added eastern Pondera,
Teton, Liberty, and Hill counties to the advisory that now goes
until 9am Thurs. Also adjusted the overnight lows in the fog areas
as several sites were at/below the forecast minimum temps. A weak
shortwave trof currently crossing western MT may help increase the
surface winds east of the Divide during the overnight hours to
help dissipate some of the fog, but confidence is only marginal
for that to occur.
Waranauskas

&&

.AVIATION...
UPDATED 2335Z.
Persistent freezing fog continues at KCTB with LIFR conditions.
Southwesterly downslope flow is expected to erode this area of fog
through the evening hours. Confidence in the timing of fog clearing
is low. Short-term guidance indicates that fog could return to KHVR,
but confidence is low and so did not include in TAF. Elsewhere,
skies are clearing this evening behind a departing weather system.
High cloud cover will increase by morning as another weak
disturbance moves into western Montana. Conditions will remain VFR
at all terminals except KCTB and possibly KHVR as highlighted above.
Nutter

&&

.PREV DISCUSSION...
/ISSUED 435 PM MST Wed Dec 17 2014/
Wednesday night through Friday...A rather quiet and cool end to
the work week is expected as no major systems are expected to move
over the area in this time frame. Temperatures will remain near
seasonal values as weak shortwave toughing on Thursday will be
followed by a week shortwave ridge on Friday. The biggest impact
during this time period will be the persistent freezing fog over
parts of Central and North Central Montana. Have extended the
advisory currently in effect until 9 pm for areas around Cut Bank
and Shelby. Westerly winds should develop around 6 pm and
eventual scour out the fog. However, there is a chance that the
nocturnal boundary layer will strengthen the inversion and will
limit any potential for the west winds to move the fog out of the
area until Thursday when a weak shortwave moves through the area.
Widespread moisture is not expected at this time with this
disturbance...however some isolated mountain snow showers are
possible. Suk

Friday Night through Wednesday...A weak shortwave trough will move
through Montana Friday night into Saturday, bringing just a chance
of snow to the mountains. Forecast models continue to indicate
that the pattern will then change for Saturday night through
Tuesday. An upper level high pressure ridge will strengthen off
the California coast and a low pressure trough will deepen from
Hudson Bay into the Great Lakes. This will result in Montana being
under a strong northwesterly flow aloft. The models indicate that
the strongest winds aloft will occur Sunday into Sunday night with
the passage of a disturbance embedded in the flow. However, the
models differ on just how strong these winds will be. The ECMWF
only forecasts winds of 45 to 55 kts at 700 mb, while the GFS
generally has 60 to 70 kt winds. Have therefore used a compromise
solution between these two models with regards to surface wind
strength. Despite this difference, this set-up will bring gusty
westerly downslope winds to much of the area, but especially over
the plains of north central Montana. In fact, some areas along the
Rocky Mountain Front could approach High Wind criteria (40 mph
sustained/58 mph gusts). Confidence remains moderate that High
Wind highlights may be needed for this event. The only concern is
that the northwesterly wind direction is not as favorable for
widespread High Winds. There is also significant moisture with
this disturbance, so have continued to spread the chance for
precipitation out onto the plains. Winds aloft will decrease
somewhat after the passage of the disturbance, but the
northwesterly flow aloft will remain fairly moist, so have kept
the chance for precipitation above climatological normals across
the area into Tuesday. A potentially significant weather system
originating in the Gulf of Alaska is then forecast to move into
Montana Tuesday into Wednesday, bringing a very good chance of
precipitation. Because this feature is near the end of the period,
exact timing and types of precipitation are very uncertain.
Regardless, this system will need to be monitored for potential
winter weather highlights, especially considering that it would be
moving into the area during peak holiday travel time. The breezy
winds through Monday will keep temperatures around 10 degrees
above normal. The warmest day of the period appears to be Monday,
when most lower elevation locations should get well into the 40s.
However, with the system moving into the area at the end of the
period, temperatures will likely fall back to near or slightly
below seasonal averages by Wednesday. Coulston

&&

.PRELIMINARY POINT TEMPS/POPS...
GTF  25  40  26  40 /  10  10  10  10
CTB  12  39  24  39 /  10  10  10  10
HLN  19  34  19  35 /  10  20  10  20
BZN  14  30  15  32 /  10  10  10  20
WEY  17  32  19  33 /  20  20  30  40
DLN  18  34  19  37 /  10  20  10  20
HVR  16  37  22  39 /  10  10  10  10
LWT  23  43  24  43 /  10  10  10  10

&&

.TFX WATCHES/WARNINGS/ADVISORIES...
FREEZING FOG ADVISORY until 9 AM MST Thursday Eastern Glacier...
Eastern Pondera...Eastern Teton...Hill...Liberty...Southern
Rocky Mountain Front...Toole.

&&

$$

weather.gov/greatfalls
www.twitter.com/NWSGreatFalls
www.facebook.com/NWSGreatFalls





  [top]

000
FXUS65 KBYZ 180335
AFDBYZ

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE BILLINGS MT
835 PM MST WED DEC 17 2014

.UPDATE...

RADAR ECHOES BOTH FROM ROUNDUP TO COLSTRIP AND AROUND BAKER ARE ON
A DOWNWARD TREND AS OF MID EVENING...AND IT SEEMS NOT MUCH REACHED
THE GROUND UNDER THEM TO BEGIN WITH. WE THUS DROPPED POPS FOR THIS
EVENING AND INSTEAD WENT WITH A SCATTERED FLURRY MENTION IN SOUTH-
EASTERN MT. WE ALSO EXTENDED IT THROUGH THE NIGHT...AND RIGHT INTO
THURSDAY MORNING AROUND BAKER AS A WEAK SHORTWAVE TROUGH CONTINUES
TO MOVE FROM EASTERN MT INTO ND. WE KEPT PATCHY FOG IN PLAY ACROSS
FAR SOUTHEASTERN MT TONIGHT AS WELL WITH SOME SUPPORT FOR IT STILL
IN RECENT HRRR RUNS. LOW-LEVEL WINDS ARE ALMOST 10 KT THOUGH AS OF
03 UTC AND IF THAT TREND CONTINUES THEN NEAR-SURFACE FLOW MIGHT BE
TOO TURBULENT FOR VISIBILITY TO LOWER VERY FAR OR FOR VERY LONG.

WE ALSO INCREASED LOWS A BIT TONIGHT GIVEN CLOUDS ACROSS SOUTHEAST
MT AND MODEST SOUTHWEST WINDS TIED TO WEAK LEE-SIDE TROUGHING OVER
SOUTH CENTRAL MT. SCHULTZ

&&

.SHORT TERM...VALID FOR THU AND FRI...

WEAK UPPER LOW PRESSURE SYSTEM WILL MOVE ACROSS NORTHERN MONTANA
TONIGHT AND WILL BRING AREAS OF LIGHT SNOW THIS EVENING ACROSS OUR
NORTHEAST ZONES. SNOW IS EXPECTED TO BE VERY LIGHT WITH NO
ACCUMULATIONS. AS THE LOW MOVES TO OUR EAST TONIGHT...SOME
CLEARING IS EXPECTED ACROSS OUR WESTERN AND CENTRAL ZONES. THIS
WILL ALLOW FOR COOLER OVERNIGHT LOW TEMPERATURES WITH TEENS TO
LOWER 20S. HRRR IS INDICATING FOG TO REDEVELOP OVER SOUTHERN
POWDER RIVER AND CARTER COUNTIES TONIGHT AS LOW LEVEL MOISTURE
REMAINS POOLED OVER THESE AREAS. DID INCLUDED PATCHY FOG FOR
PORTIONS OF SOUTHEAST MONTANA TONIGHT. WEAK SHORT WAVE TO MOVE
THROUGH THURSDAY WHICH WHICH WILL BRING SCATTERED SNOW SHOWERS TO
OUR SOUTHWEST MOUNTAINS. DRY WEATHER AND SLOWLY WARMING
TEMPERATURES WILL CONTINUE INTO FRIDAY AS SHORT WAVE RIDGING MOVES
IN OVER THE REGION. HIGH TEMPERATURES WILL BE IN THE UPPER 30S TO
LOWER 40S BOTH THURSDAY AND FRIDAY. RICHMOND

.LONG TERM...VALID FOR SAT...SUN...MON...TUE...WED...

GUIDANCE CONTINUES TO BE IN GOOD AGREEMENT INTO EARLY NEXT WEEK.
WHILE THE FINER DETAILS MAY DIFFER...THE OVERALL UNSETTLED
PATTERN IN THE EXTENDED CONTINUES. AFTER THE RIDGING FRIDAY...A
WEAK SHORTWAVE WILL CROSS THE STATE...BRINGING ANOTHER CHANCE FOR
LIGHT PRECIP TO THE MOUNTAINS. UPPER LEVEL FLOW BEGINS TO INCREASE
SATURDAY NIGHT AS A PACIFIC JET STARTS MOVING INTO THE STATE. LEE
SIDE TROUGHING DEVELOPS...WITH A SURFACE LOW DEVELOPING OVER
SOUTHERN ALBERTA. IN RESPONSE...THE PRESSURE GRADIENT TIGHTENS
OVER SOUTHERN MONTANA...RESULTING IN STRONGER WINDS DEVELOPING
FIRST IN THE GAP AREAS...THEN SPREADING OUT TO AROUND BILLINGS.
MEX MOS FOR LIVINGSTON HAS WINDS INCREASING INTO 30 MPH TO NEAR 40
MPH RANGE SUNDAY AFTERNOON. STILL KEEPING GRIDS SUB ADVISORY GIVEN
THIS IS STILL FOUR DAYS OUT...BUT IF CURRENT TRENDS HOLD...LOOKING
AT ANOTHER WIND EVENT DURING THE DAY SUNDAY.

AS THE LOW TRACKS OUT OF CANADA INTO THE NORTHERN PLAINS
MONDAY...A COLD FRONT MOVES THROUGH THE AREA. WITH AMPLE MOISTURE
STILL BRING TRANSPORTED INTO THE AREA...POPS CONTINUE MONDAY INTO
TUESDAY. TEMPERATURES WILL REMAIN RELATIVELY WARM...SO MUCH OF THE
CENTRAL ZONES STILL LOOK TO GET RAIN. FARTHER EAST WARDS MILES
CITY AND BAKER...WHERE TEMPERATURES ARE A BIT COOLER...MAY SEE
SOME FREEZING RAIN. WINDS WILL ALSO BE MORE NORTH WESTERLY...SO
NOT AS MUCH OF AN UP SLOPE FLOW EVENT. THINGS BEGIN TO TAPPER
OFF...WITH TEMPERATURES COOLING BACK INTO THE 30S FOR HIGHS.

LOOKING AHEAD TO CHRISTMAS EVE AND CHRISTMAS...ANOTHER LOW
DEVELOPS AND TRACKS ACROSS MONTANA...GIVING THE AREA A SHOT AT
MORE PRECIP. WITH THE SYSTEM...THE AIR MASS IN PLACE WILL BE
COLDER...WITH 850MB TEMPERATURES BELOW FREEZING. THE THE GFS AND
ECMWF ARE SUGGESTING A SHOT AT A WHITE CHRISTMAS...WILL CONTINUE
TO WATCH THIS. REIMER

&&

.AVIATION...

FLIGHT CONDITIONS REMAIN MAINLY VFR/MVFR OVERNIGHT AND INTO
TOMORROW....HOWEVER SOME PATCHY FOG IS POSSIBLE FROM KMLS SOUTH
AND EAST. OCCASIONAL MOUNTAIN OBSCURATION WILL CONTINUE
OVERNIGHT...WITH MID LEVEL CLOUDS CROSSING THE REGION. AAG

&&

.PRELIMINARY POINT TEMP/POPS...

    THU     FRI     SAT     SUN     MON     TUE     WED
-----------------------------------------------------------
BIL 023/038 023/038 027/041 027/046 033/045 026/038 022/033
    00/B    00/B    11/B    13/W    32/W    21/N    23/J
LVM 024/042 024/040 027/043 028/046 035/045 022/039 023/035
    01/N    11/N    21/B    24/W    43/W    21/N    33/J
HDN 018/037 015/037 020/040 021/044 029/043 021/037 020/034
    10/B    00/B    01/B    13/W    33/W    21/B    22/J
MLS 018/038 019/037 021/040 022/042 029/040 025/036 020/031
    10/B    00/B    11/B    13/W    22/W    11/B    11/E
4BQ 017/041 017/040 019/041 022/044 030/042 024/037 019/033
    10/B    00/B    11/B    12/W    23/W    21/B    22/J
BHK 016/036 019/037 019/040 021/042 026/037 021/033 017/027
    11/M    10/B    01/B    02/W    22/W    11/N    11/B
SHR 012/041 015/038 020/040 019/043 030/042 022/037 019/033
    10/B    10/B    11/B    13/W    34/W    32/J    22/J

&&

.BYZ WATCHES/WARNINGS/ADVISORIES...
MT...NONE.
WY...NONE.

&&

$$
WEATHER.GOV/BILLINGS


  [top]

000
FXUS65 KGGW 180252 AAA
AFDGGW

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE GLASGOW MT
752 PM MST WED DEC 17 2014

.SHORT TERM...FOR NORTHEAST MONTANA...TONIGHT THROUGH FRIDAY...

SENT AN UPDATE TONIGHT TO REDUCE POPS AND CLEAR PRECIP OUT TO
FLURRIES...FOLLOWING FORECAST SOUNDING AND LATEST MODEL PRECIP
OUTPUT. ALSO CANCELLED THE DENSE FOG ADVISORY AS AREA OBSERVATIONS
AND SPOTTER REPORT INDICATE THAT THE VISIBILITIES HAVE IMPROVED AND
CLOUD DECK HAS LIFTED ENOUGH TO NO LONGER POSE A THREAT TO THOSE
HIGHER ELEVATION AREAS. A FEW ISOLATED AREAS OF PATCHY MIST OR FOG
MAY BRIEFLY BE POSSIBLE STILL TONIGHT...BUT CONFIDENCE IS LOW.
BMICKELSON

PREVIOUS SHORT TERM DISCUSSION...PATCHY DENSE FREEZING FOG
CONTINUES ACROSS THE OPHEIM AREA THIS AFTERNOON AND WILL HAVE THE
DENSE FOG ADVISORY EXTENDED UNTIL 9 PM. THE NEXT SHIFT CAN MONITOR
TRENDS TO BEST DETERMINE IF OR WHEN FOG MAY LIFT. OTHERWISE EXPECT
LOW STRATUS TO CONTINUE TO PLAGUE THE CWA. WILL CONTINUE WITH
SLIGHT CHANCE POPS OVERNIGHT ACROSS PORTIONS OF THE
REGION...FOLLOWING 12Z NAM GUIDANCE IN PARTICULAR. EXPECT MAINLY
LIGHT SNOW OR PERHAPS A MIX WITH FREEZING RAIN BUT AMOUNTS SHOULD
BE QUITE MINIMAL.

A WEAK UPPER SHORTWAVE WILL PASS ACROSS THE REGION ON THURSDAY AND
THURSDAY NIGHT WITH A SHORTWAVE RIDGE BUILDING IN ON FRIDAY. THIS
WILL BRING ABOUT A WIND SHIFT TO THE WEST...HELPING TO REMOVE
POTENTIAL FOR LOW STRATUS AND FOG GRADUALLY WITH TIME. THUS...THE
TREND TOWARD THE END OF THE WEEK WILL BE FOR DRIER CONDITIONS AND
MODERATING TEMPERATURES. MUCH OF NORTHEAST MONTANA WILL SEE HIGHS
BY FRIDAY MARCH ABOVE FREEZING WITH THE EXCEPTION OF DEEPER VALLEY
LOCATIONS AND PLACES ALONG THE CANADIAN BORDER. MALIAWCO


.LONG TERM...FRIDAY NIGHT THROUGH WEDNESDAY...

THE BEST POTENTIAL FOR PRECIPITATION NOW LOOKS TO COME SUNDAY.
POPS WERE RAISED AND THE PRECIPITATION LOOKS TO OCCUR WITH
TEMPERATURES AT OR ABOVE FREEZING BUT THERE WILL BE CONCERNS FOR
FREEZING RAIN AND SOME SNOW. WILL HIGHLIGHT THIS IN AN HAZARDOUS
WEATHER OUTLOOK BUT IT LOOKS TO BE A MARGINAL EVENT AT THIS TIME.

REST OF FORECAST LOOKED GOOD. THERE IS SOME POTENTIAL FOR STRONG NW
WINDS AFTER SUNDAY/S DISTURBANCE PASSES...ABOUT TUESDAY...BUT 850 MB
WINDS ONLY GET TO ABOUT 40 KTS. THEREFORE NOT EXPECTING WIDESPREAD
STRONG WINDS. POSSIBLY ISSUES IN THE NORMALLY WINDY SPOTS (I.E. SE
PHILLIPS COUNTY). TFJ

PREVIOUS DISCUSSION...

THE GENERAL SYNOPTIC FLOW REGIME FOR THE EXTENDED FORECAST PERIOD
WILL BE FROM THE WEST AND NORTHWEST WITH A FEW EMBEDDED SMALL-
SCALE DISTURBANCES EARLY IN THE PERIOD...FOLLOWED BY A LARGER-
SCALE STORM SYSTEM OVER THE REGION TOWARD CHRISTMAS EVE.

FIRST...EARLY SUNDAY MORNING...A SMALL DISTURBANCE EMERGES OVER
THE CANADIAN ROCKIES AND GAINS ENOUGH FORCING AND MOISTURE TO
SQUEEZE OUT SOME LIGHT PRECIPITATION. BASICALLY WENT WITH A MODEL
BLEND HERE...SLIGHTLY FAVORING THE EC FOR ITS RUN TO RUN
CONSISTENCY. NOT EXPECTING MUCH...MAYBE A HALF INCH OF SNOW NORTH
OF THE MISSOURI RIVER AND SOME LIGHT RAIN SOUTH OF THE MISSOURI
RIVER.

MONDAY NIGHT THROUGH WEDNESDAY NIGHT...A STRONGER AND MORE-
ESTABLISHED NORTHWESTERLY FLOW ALOFT SEEMS TO TAKE ROOT OVER THE
REGION AND SETS UP SOME HIGHER ELEVATION AREAS OF CENTRAL MONTANA
WITH OVER-RUNNING AND ACCUMULATING PRECIPITATION. THIS WILL LIKELY
REMAIN CONFINED TO THE NE AND SW CORNERS OF OUR CWA. MODELS
INDICATE THAT THIS PRECIPITATION TREND WILL LATER THE BECOME
ENHANCED BY A COLD AIR MASS...LARGER TROUGH...AND STRONGER STORM
SYSTEM POSSIBLY BY CHRISTMAS TIME. TRIED TO REFLECT THIS THINKING
WITH THE FORECAST GRIDS. BMICKELSON

&&

.AVIATION...

SYNOPSIS: WEAK FLOW ALOFT WILL CONTINUE OVER THE REGION THROUGH
THE TERMINAL FORECAST PERIOD.

FLIGHT CATEGORY: MVFR...ISOLATED IFR.

CIGS AND VSBY: CIGS WILL RANGE FROM 010-020 WITH A SOLID STRATUS
DECK HOLDING IN OVER THE AREA.

WIND: SOUTHEAST UNDER 15 KNOTS EXPECTED.

PROTON


&&

.GLASGOW WATCHES/WARNINGS/ADVISORIES...NONE.

&&

$$

WEATHER.GOV/GLASGOW





000
FXUS65 KGGW 180252 AAA
AFDGGW

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE GLASGOW MT
752 PM MST WED DEC 17 2014

.SHORT TERM...FOR NORTHEAST MONTANA...TONIGHT THROUGH FRIDAY...

SENT AN UPDATE TONIGHT TO REDUCE POPS AND CLEAR PRECIP OUT TO
FLURRIES...FOLLOWING FORECAST SOUNDING AND LATEST MODEL PRECIP
OUTPUT. ALSO CANCELLED THE DENSE FOG ADVISORY AS AREA OBSERVATIONS
AND SPOTTER REPORT INDICATE THAT THE VISIBILITIES HAVE IMPROVED AND
CLOUD DECK HAS LIFTED ENOUGH TO NO LONGER POSE A THREAT TO THOSE
HIGHER ELEVATION AREAS. A FEW ISOLATED AREAS OF PATCHY MIST OR FOG
MAY BRIEFLY BE POSSIBLE STILL TONIGHT...BUT CONFIDENCE IS LOW.
BMICKELSON

PREVIOUS SHORT TERM DISCUSSION...PATCHY DENSE FREEZING FOG
CONTINUES ACROSS THE OPHEIM AREA THIS AFTERNOON AND WILL HAVE THE
DENSE FOG ADVISORY EXTENDED UNTIL 9 PM. THE NEXT SHIFT CAN MONITOR
TRENDS TO BEST DETERMINE IF OR WHEN FOG MAY LIFT. OTHERWISE EXPECT
LOW STRATUS TO CONTINUE TO PLAGUE THE CWA. WILL CONTINUE WITH
SLIGHT CHANCE POPS OVERNIGHT ACROSS PORTIONS OF THE
REGION...FOLLOWING 12Z NAM GUIDANCE IN PARTICULAR. EXPECT MAINLY
LIGHT SNOW OR PERHAPS A MIX WITH FREEZING RAIN BUT AMOUNTS SHOULD
BE QUITE MINIMAL.

A WEAK UPPER SHORTWAVE WILL PASS ACROSS THE REGION ON THURSDAY AND
THURSDAY NIGHT WITH A SHORTWAVE RIDGE BUILDING IN ON FRIDAY. THIS
WILL BRING ABOUT A WIND SHIFT TO THE WEST...HELPING TO REMOVE
POTENTIAL FOR LOW STRATUS AND FOG GRADUALLY WITH TIME. THUS...THE
TREND TOWARD THE END OF THE WEEK WILL BE FOR DRIER CONDITIONS AND
MODERATING TEMPERATURES. MUCH OF NORTHEAST MONTANA WILL SEE HIGHS
BY FRIDAY MARCH ABOVE FREEZING WITH THE EXCEPTION OF DEEPER VALLEY
LOCATIONS AND PLACES ALONG THE CANADIAN BORDER. MALIAWCO


.LONG TERM...FRIDAY NIGHT THROUGH WEDNESDAY...

THE BEST POTENTIAL FOR PRECIPITATION NOW LOOKS TO COME SUNDAY.
POPS WERE RAISED AND THE PRECIPITATION LOOKS TO OCCUR WITH
TEMPERATURES AT OR ABOVE FREEZING BUT THERE WILL BE CONCERNS FOR
FREEZING RAIN AND SOME SNOW. WILL HIGHLIGHT THIS IN AN HAZARDOUS
WEATHER OUTLOOK BUT IT LOOKS TO BE A MARGINAL EVENT AT THIS TIME.

REST OF FORECAST LOOKED GOOD. THERE IS SOME POTENTIAL FOR STRONG NW
WINDS AFTER SUNDAY/S DISTURBANCE PASSES...ABOUT TUESDAY...BUT 850 MB
WINDS ONLY GET TO ABOUT 40 KTS. THEREFORE NOT EXPECTING WIDESPREAD
STRONG WINDS. POSSIBLY ISSUES IN THE NORMALLY WINDY SPOTS (I.E. SE
PHILLIPS COUNTY). TFJ

PREVIOUS DISCUSSION...

THE GENERAL SYNOPTIC FLOW REGIME FOR THE EXTENDED FORECAST PERIOD
WILL BE FROM THE WEST AND NORTHWEST WITH A FEW EMBEDDED SMALL-
SCALE DISTURBANCES EARLY IN THE PERIOD...FOLLOWED BY A LARGER-
SCALE STORM SYSTEM OVER THE REGION TOWARD CHRISTMAS EVE.

FIRST...EARLY SUNDAY MORNING...A SMALL DISTURBANCE EMERGES OVER
THE CANADIAN ROCKIES AND GAINS ENOUGH FORCING AND MOISTURE TO
SQUEEZE OUT SOME LIGHT PRECIPITATION. BASICALLY WENT WITH A MODEL
BLEND HERE...SLIGHTLY FAVORING THE EC FOR ITS RUN TO RUN
CONSISTENCY. NOT EXPECTING MUCH...MAYBE A HALF INCH OF SNOW NORTH
OF THE MISSOURI RIVER AND SOME LIGHT RAIN SOUTH OF THE MISSOURI
RIVER.

MONDAY NIGHT THROUGH WEDNESDAY NIGHT...A STRONGER AND MORE-
ESTABLISHED NORTHWESTERLY FLOW ALOFT SEEMS TO TAKE ROOT OVER THE
REGION AND SETS UP SOME HIGHER ELEVATION AREAS OF CENTRAL MONTANA
WITH OVER-RUNNING AND ACCUMULATING PRECIPITATION. THIS WILL LIKELY
REMAIN CONFINED TO THE NE AND SW CORNERS OF OUR CWA. MODELS
INDICATE THAT THIS PRECIPITATION TREND WILL LATER THE BECOME
ENHANCED BY A COLD AIR MASS...LARGER TROUGH...AND STRONGER STORM
SYSTEM POSSIBLY BY CHRISTMAS TIME. TRIED TO REFLECT THIS THINKING
WITH THE FORECAST GRIDS. BMICKELSON

&&

.AVIATION...

SYNOPSIS: WEAK FLOW ALOFT WILL CONTINUE OVER THE REGION THROUGH
THE TERMINAL FORECAST PERIOD.

FLIGHT CATEGORY: MVFR...ISOLATED IFR.

CIGS AND VSBY: CIGS WILL RANGE FROM 010-020 WITH A SOLID STRATUS
DECK HOLDING IN OVER THE AREA.

WIND: SOUTHEAST UNDER 15 KNOTS EXPECTED.

PROTON


&&

.GLASGOW WATCHES/WARNINGS/ADVISORIES...NONE.

&&

$$

WEATHER.GOV/GLASGOW






000
FXUS65 KTFX 172350
AFDTFX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREAT FALLS MT
435 PM MST Wed Dec 17 2014

Aviation Section Updated.

.DISCUSSION...
Wednesday night through Friday...A rather quiet and cool end to
the work week is expected as no major systems are expected to move
over the area in this time frame. Temperatures will remain near
seasonal values as weak shortwave toughing on Thursday will be
followed by a week shortwave ridge on Friday. The biggest impact
during this time period will be the persistent freezing fog over
parts of Central and North Central Montana. Have extended the
advisory currently in effect until 9 pm for areas around Cut Bank
and Shelby. Westerly winds should develop around 6 pm and
eventual scour out the fog. However, there is a chance that the
nocturnal boundary layer will strengthen the inversion and will
limit any potential for the west winds to move the fog out of the
area until Thursday when a weak shortwave moves through the area.
Widespread moisture is not expected at this time with this
disturbance...however some isolated mountain snow showers are
possible. Suk

Friday Night through Wednesday...A weak shortwave trough will move
through Montana Friday night into Saturday, bringing just a chance
of snow to the mountains. Forecast models continue to indicate
that the pattern will then change for Saturday night through
Tuesday. An upper level high pressure ridge will strengthen off
the California coast and a low pressure trough will deepen from
Hudson Bay into the Great Lakes. This will result in Montana being
under a strong northwesterly flow aloft. The models indicate that
the strongest winds aloft will occur Sunday into Sunday night with
the passage of a disturbance embedded in the flow. However, the
models differ on just how strong these winds will be. The ECMWF
only forecasts winds of 45 to 55 kts at 700 mb, while the GFS
generally has 60 to 70 kt winds. Have therefore used a compromise
solution between these two models with regards to surface wind
strength. Despite this difference, this set-up will bring gusty
westerly downslope winds to much of the area, but especially over
the plains of north central Montana. In fact, some areas along the
Rocky Mountain Front could approach High Wind criteria (40 mph
sustained/58 mph gusts). Confidence remains moderate that High
Wind highlights may be needed for this event. The only concern is
that the northwesterly wind direction is not as favorable for
widespread High Winds. There is also significant moisture with
this disturbance, so have continued to spread the chance for
precipitation out onto the plains. Winds aloft will decrease
somewhat after the passage of the disturbance, but the
northwesterly flow aloft will remain fairly moist, so have kept
the chance for precipitation above climatological normals across
the area into Tuesday. A potentially significant weather system
originating in the Gulf of Alaska is then forecast to move into
Montana Tuesday into Wednesday, bringing a very good chance of
precipitation. Because this feature is near the end of the period,
exact timing and types of precipitation are very uncertain.
Regardless, this system will need to be monitored for potential
winter weather highlights, especially considering that it would be
moving into the area during peak holiday travel time. The breezy
winds through Monday will keep temperatures around 10 degrees
above normal. The warmest day of the period appears to be Monday,
when most lower elevation locations should get well into the 40s.
However, with the system moving into the area at the end of the
period, temperatures will likely fall back to near or slightly
below seasonal averages by Wednesday. Coulston

&&

.AVIATION...
UPDATED 2335Z.
Persistent freezing fog continues at KCTB with LIFR conditions.
Southwesterly downslope flow is expected to erode this area of fog
through the evening hours. Confidence in the timing of fog clearing
is low. Short-term guidance indicates that fog could return to KHVR,
but confidence is low and so did not include in TAF. Elsewhere,
skies are clearing this evening behind a departing weather system.
High cloud cover will increase by morning as another weak
disturbance moves into western Montana. Conditions will remain VFR
at all terminals except KCTB and possibly KHVR as highlighted above.
Nutter

&&

.PRELIMINARY POINT TEMPS/POPS...
GTF  23  40  26  40 /  10  10  10  10
CTB  21  39  24  39 /  10  10  10  10
HLN  18  34  19  35 /  10  20  10  20
BZN  14  30  15  32 /  10  10  10  20
WEY  16  32  19  33 /  20  20  30  40
DLN  17  34  19  37 /  10  20  10  20
HVR  18  37  22  39 /  10  10  10  10
LWT  21  43  24  43 /  10  10  10  10

&&

.TFX WATCHES/WARNINGS/ADVISORIES...
FREEZING FOG ADVISORY until 9 PM MST this evening Eastern
Glacier...Toole.

&&

$$

weather.gov/greatfalls
www.twitter.com/NWSGreatFalls
www.facebook.com/NWSGreatFalls








000
FXUS65 KTFX 172350
AFDTFX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREAT FALLS MT
435 PM MST Wed Dec 17 2014

Aviation Section Updated.

.DISCUSSION...
Wednesday night through Friday...A rather quiet and cool end to
the work week is expected as no major systems are expected to move
over the area in this time frame. Temperatures will remain near
seasonal values as weak shortwave toughing on Thursday will be
followed by a week shortwave ridge on Friday. The biggest impact
during this time period will be the persistent freezing fog over
parts of Central and North Central Montana. Have extended the
advisory currently in effect until 9 pm for areas around Cut Bank
and Shelby. Westerly winds should develop around 6 pm and
eventual scour out the fog. However, there is a chance that the
nocturnal boundary layer will strengthen the inversion and will
limit any potential for the west winds to move the fog out of the
area until Thursday when a weak shortwave moves through the area.
Widespread moisture is not expected at this time with this
disturbance...however some isolated mountain snow showers are
possible. Suk

Friday Night through Wednesday...A weak shortwave trough will move
through Montana Friday night into Saturday, bringing just a chance
of snow to the mountains. Forecast models continue to indicate
that the pattern will then change for Saturday night through
Tuesday. An upper level high pressure ridge will strengthen off
the California coast and a low pressure trough will deepen from
Hudson Bay into the Great Lakes. This will result in Montana being
under a strong northwesterly flow aloft. The models indicate that
the strongest winds aloft will occur Sunday into Sunday night with
the passage of a disturbance embedded in the flow. However, the
models differ on just how strong these winds will be. The ECMWF
only forecasts winds of 45 to 55 kts at 700 mb, while the GFS
generally has 60 to 70 kt winds. Have therefore used a compromise
solution between these two models with regards to surface wind
strength. Despite this difference, this set-up will bring gusty
westerly downslope winds to much of the area, but especially over
the plains of north central Montana. In fact, some areas along the
Rocky Mountain Front could approach High Wind criteria (40 mph
sustained/58 mph gusts). Confidence remains moderate that High
Wind highlights may be needed for this event. The only concern is
that the northwesterly wind direction is not as favorable for
widespread High Winds. There is also significant moisture with
this disturbance, so have continued to spread the chance for
precipitation out onto the plains. Winds aloft will decrease
somewhat after the passage of the disturbance, but the
northwesterly flow aloft will remain fairly moist, so have kept
the chance for precipitation above climatological normals across
the area into Tuesday. A potentially significant weather system
originating in the Gulf of Alaska is then forecast to move into
Montana Tuesday into Wednesday, bringing a very good chance of
precipitation. Because this feature is near the end of the period,
exact timing and types of precipitation are very uncertain.
Regardless, this system will need to be monitored for potential
winter weather highlights, especially considering that it would be
moving into the area during peak holiday travel time. The breezy
winds through Monday will keep temperatures around 10 degrees
above normal. The warmest day of the period appears to be Monday,
when most lower elevation locations should get well into the 40s.
However, with the system moving into the area at the end of the
period, temperatures will likely fall back to near or slightly
below seasonal averages by Wednesday. Coulston

&&

.AVIATION...
UPDATED 2335Z.
Persistent freezing fog continues at KCTB with LIFR conditions.
Southwesterly downslope flow is expected to erode this area of fog
through the evening hours. Confidence in the timing of fog clearing
is low. Short-term guidance indicates that fog could return to KHVR,
but confidence is low and so did not include in TAF. Elsewhere,
skies are clearing this evening behind a departing weather system.
High cloud cover will increase by morning as another weak
disturbance moves into western Montana. Conditions will remain VFR
at all terminals except KCTB and possibly KHVR as highlighted above.
Nutter

&&

.PRELIMINARY POINT TEMPS/POPS...
GTF  23  40  26  40 /  10  10  10  10
CTB  21  39  24  39 /  10  10  10  10
HLN  18  34  19  35 /  10  20  10  20
BZN  14  30  15  32 /  10  10  10  20
WEY  16  32  19  33 /  20  20  30  40
DLN  17  34  19  37 /  10  20  10  20
HVR  18  37  22  39 /  10  10  10  10
LWT  21  43  24  43 /  10  10  10  10

&&

.TFX WATCHES/WARNINGS/ADVISORIES...
FREEZING FOG ADVISORY until 9 PM MST this evening Eastern
Glacier...Toole.

&&

$$

weather.gov/greatfalls
www.twitter.com/NWSGreatFalls
www.facebook.com/NWSGreatFalls







000
FXUS65 KGGW 172204
AFDGGW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GLASGOW MT
304 PM MST WED DEC 17 2014

.SHORT TERM...FOR NORTHEAST MONTANA...TONIGHT THROUGH FRIDAY...
PATCHY DENSE FREEZING FOG CONTINUES ACROSS THE OPHEIM AREA THIS
AFTERNOON AND WILL HAVE THE DENSE FOG ADVISORY EXTENDED UNTIL 9
PM. THE NEXT SHIFT CAN MONITOR TRENDS TO BEST DETERMINE IF OR WHEN
FOG MAY LIFT. OTHERWISE EXPECT LOW STRATUS TO CONTINUE TO PLAGUE
THE CWA. WILL CONTINUE WITH SLIGHT CHANCE POPS OVERNIGHT ACROSS
PORTIONS OF THE REGION...FOLLOWING 12Z NAM GUIDANCE IN PARTICULAR.
EXPECT MAINLY LIGHT SNOW OR PERHAPS A MIX WITH FREEZING RAIN BUT
AMOUNTS SHOULD BE QUITE MINIMAL.

A WEAK UPPER SHORTWAVE WILL PASS ACROSS THE REGION ON THURSDAY AND
THURSDAY NIGHT WITH A SHORTWAVE RIDGE BUILDING IN ON FRIDAY. THIS
WILL BRING ABOUT A WIND SHIFT TO THE WEST...HELPING TO REMOVE
POTENTIAL FOR LOW STRATUS AND FOG GRADUALLY WITH TIME. THUS...THE
TREND TOWARD THE END OF THE WEEK WILL BE FOR DRIER CONDITIONS AND
MODERATING TEMPERATURES. MUCH OF NORTHEAST MONTANA WILL SEE HIGHS
BY FRIDAY MARCH ABOVE FREEZING WITH THE EXCEPTION OF DEEPER VALLEY
LOCATIONS AND PLACES ALONG THE CANADIAN BORDER. MALIAWCO


.LONG TERM...FRIDAY NIGHT THROUGH WEDNESDAY...
THE BEST POTENTIAL FOR PRECIPITATION NOW LOOKS TO COME SUNDAY. POPS
WERE RAISED AND THE PRECIPITATION LOOKS TO OCCUR WITH TEMPERATURES
AT OR ABOVE FREEZING BUT THERE WILL BE CONCERNS FOR FREEZING RAIN
AND SOME SNOW. WILL HIGHLIGHT THIS IN AN HAZARDOUS WEATHER OUTLOOK
BUT IT LOOKS TO BE A MARGINAL EVENT AT THIS TIME.

REST OF FORECAST LOOKED GOOD. THERE IS SOME POTENTIAL FOR STRONG NW
WINDS AFTER SUNDAY/S DISTURBANCE PASSES...ABOUT TUESDAY...BUT 850 MB
WINDS ONLY GET TO ABOUT 40 KTS. THEREFORE NOT EXPECTING WIDESPREAD
STRONG WINDS. POSSIBLY ISSUES IN THE NORMALLY WINDY SPOTS (I.E. SE
PHILLIPS COUNTY). TFJ

PREVIOUS DISCUSSION...
THE GENERAL SYNOPTIC FLOW REGIME FOR THE EXTENDED FORECAST PERIOD
WILL BE FROM THE WEST AND NORTHWEST WITH A FEW EMBEDDED SMALL-
SCALE DISTURBANCES EARLY IN THE PERIOD...FOLLOWED BY A LARGER-
SCALE STORM SYSTEM OVER THE REGION TOWARD CHRISTMAS EVE.

FIRST...EARLY SUNDAY MORNING...A SMALL DISTURBANCE EMERGES OVER
THE CANADIAN ROCKIES AND GAINS ENOUGH FORCING AND MOISTURE TO
SQUEEZE OUT SOME LIGHT PRECIPITATION. BASICALLY WENT WITH A MODEL
BLEND HERE...SLIGHTLY FAVORING THE EC FOR ITS RUN TO RUN
CONSISTENCY. NOT EXPECTING MUCH...MAYBE A HALF INCH OF SNOW NORTH
OF THE MISSOURI RIVER AND SOME LIGHT RAIN SOUTH OF THE MISSOURI
RIVER.

MONDAY NIGHT THROUGH WEDNESDAY NIGHT...A STRONGER AND MORE-
ESTABLISHED NORTHWESTERLY FLOW ALOFT SEEMS TO TAKE ROOT OVER THE
REGION AND SETS UP SOME HIGHER ELEVATION AREAS OF CENTRAL MONTANA
WITH OVER-RUNNING AND ACCUMULATING PRECIPITATION. THIS WILL LIKELY
REMAIN CONFINED TO THE NE AND SW CORNERS OF OUR CWA. MODELS
INDICATE THAT THIS PRECIPITATION TREND WILL LATER THE BECOME
ENHANCED BY A COLD AIR MASS...LARGER TROUGH...AND STRONGER STORM
SYSTEM POSSIBLY BY CHRISTMAS TIME. TRIED TO REFLECT THIS THINKING
WITH THE FORECAST GRIDS. BMICKELSON

&&

.AVIATION...
MVFR TO IFR STRATUS WILL CONTINUE OVERNIGHT. ISOLATED SNOW SHOWERS
AND/OR LIGHT FREEZING RAIN WILL NOT BE ENOUGH TO RESTRICT
VISIBILITY OR PRODUCE MEANINGFUL IMPACTS AS AMOUNTS WILL BE
MINIMAL. EXPECT SOUTHEAST WINDS AROUND 10 KTS OVERNIGHT. MALIAWCO

&&

.GLASGOW WATCHES/WARNINGS/ADVISORIES...
DENSE FOG ADVISORY UNTIL 9 PM MST THIS EVENING FOR NORTHERN
VALLEY.

&&

$$

WEATHER.GOV/GLASGOW





000
FXUS65 KGGW 172204
AFDGGW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GLASGOW MT
304 PM MST WED DEC 17 2014

.SHORT TERM...FOR NORTHEAST MONTANA...TONIGHT THROUGH FRIDAY...
PATCHY DENSE FREEZING FOG CONTINUES ACROSS THE OPHEIM AREA THIS
AFTERNOON AND WILL HAVE THE DENSE FOG ADVISORY EXTENDED UNTIL 9
PM. THE NEXT SHIFT CAN MONITOR TRENDS TO BEST DETERMINE IF OR WHEN
FOG MAY LIFT. OTHERWISE EXPECT LOW STRATUS TO CONTINUE TO PLAGUE
THE CWA. WILL CONTINUE WITH SLIGHT CHANCE POPS OVERNIGHT ACROSS
PORTIONS OF THE REGION...FOLLOWING 12Z NAM GUIDANCE IN PARTICULAR.
EXPECT MAINLY LIGHT SNOW OR PERHAPS A MIX WITH FREEZING RAIN BUT
AMOUNTS SHOULD BE QUITE MINIMAL.

A WEAK UPPER SHORTWAVE WILL PASS ACROSS THE REGION ON THURSDAY AND
THURSDAY NIGHT WITH A SHORTWAVE RIDGE BUILDING IN ON FRIDAY. THIS
WILL BRING ABOUT A WIND SHIFT TO THE WEST...HELPING TO REMOVE
POTENTIAL FOR LOW STRATUS AND FOG GRADUALLY WITH TIME. THUS...THE
TREND TOWARD THE END OF THE WEEK WILL BE FOR DRIER CONDITIONS AND
MODERATING TEMPERATURES. MUCH OF NORTHEAST MONTANA WILL SEE HIGHS
BY FRIDAY MARCH ABOVE FREEZING WITH THE EXCEPTION OF DEEPER VALLEY
LOCATIONS AND PLACES ALONG THE CANADIAN BORDER. MALIAWCO


.LONG TERM...FRIDAY NIGHT THROUGH WEDNESDAY...
THE BEST POTENTIAL FOR PRECIPITATION NOW LOOKS TO COME SUNDAY. POPS
WERE RAISED AND THE PRECIPITATION LOOKS TO OCCUR WITH TEMPERATURES
AT OR ABOVE FREEZING BUT THERE WILL BE CONCERNS FOR FREEZING RAIN
AND SOME SNOW. WILL HIGHLIGHT THIS IN AN HAZARDOUS WEATHER OUTLOOK
BUT IT LOOKS TO BE A MARGINAL EVENT AT THIS TIME.

REST OF FORECAST LOOKED GOOD. THERE IS SOME POTENTIAL FOR STRONG NW
WINDS AFTER SUNDAY/S DISTURBANCE PASSES...ABOUT TUESDAY...BUT 850 MB
WINDS ONLY GET TO ABOUT 40 KTS. THEREFORE NOT EXPECTING WIDESPREAD
STRONG WINDS. POSSIBLY ISSUES IN THE NORMALLY WINDY SPOTS (I.E. SE
PHILLIPS COUNTY). TFJ

PREVIOUS DISCUSSION...
THE GENERAL SYNOPTIC FLOW REGIME FOR THE EXTENDED FORECAST PERIOD
WILL BE FROM THE WEST AND NORTHWEST WITH A FEW EMBEDDED SMALL-
SCALE DISTURBANCES EARLY IN THE PERIOD...FOLLOWED BY A LARGER-
SCALE STORM SYSTEM OVER THE REGION TOWARD CHRISTMAS EVE.

FIRST...EARLY SUNDAY MORNING...A SMALL DISTURBANCE EMERGES OVER
THE CANADIAN ROCKIES AND GAINS ENOUGH FORCING AND MOISTURE TO
SQUEEZE OUT SOME LIGHT PRECIPITATION. BASICALLY WENT WITH A MODEL
BLEND HERE...SLIGHTLY FAVORING THE EC FOR ITS RUN TO RUN
CONSISTENCY. NOT EXPECTING MUCH...MAYBE A HALF INCH OF SNOW NORTH
OF THE MISSOURI RIVER AND SOME LIGHT RAIN SOUTH OF THE MISSOURI
RIVER.

MONDAY NIGHT THROUGH WEDNESDAY NIGHT...A STRONGER AND MORE-
ESTABLISHED NORTHWESTERLY FLOW ALOFT SEEMS TO TAKE ROOT OVER THE
REGION AND SETS UP SOME HIGHER ELEVATION AREAS OF CENTRAL MONTANA
WITH OVER-RUNNING AND ACCUMULATING PRECIPITATION. THIS WILL LIKELY
REMAIN CONFINED TO THE NE AND SW CORNERS OF OUR CWA. MODELS
INDICATE THAT THIS PRECIPITATION TREND WILL LATER THE BECOME
ENHANCED BY A COLD AIR MASS...LARGER TROUGH...AND STRONGER STORM
SYSTEM POSSIBLY BY CHRISTMAS TIME. TRIED TO REFLECT THIS THINKING
WITH THE FORECAST GRIDS. BMICKELSON

&&

.AVIATION...
MVFR TO IFR STRATUS WILL CONTINUE OVERNIGHT. ISOLATED SNOW SHOWERS
AND/OR LIGHT FREEZING RAIN WILL NOT BE ENOUGH TO RESTRICT
VISIBILITY OR PRODUCE MEANINGFUL IMPACTS AS AMOUNTS WILL BE
MINIMAL. EXPECT SOUTHEAST WINDS AROUND 10 KTS OVERNIGHT. MALIAWCO

&&

.GLASGOW WATCHES/WARNINGS/ADVISORIES...
DENSE FOG ADVISORY UNTIL 9 PM MST THIS EVENING FOR NORTHERN
VALLEY.

&&

$$

WEATHER.GOV/GLASGOW





000
FXUS65 KGGW 172204
AFDGGW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GLASGOW MT
304 PM MST WED DEC 17 2014

.SHORT TERM...FOR NORTHEAST MONTANA...TONIGHT THROUGH FRIDAY...
PATCHY DENSE FREEZING FOG CONTINUES ACROSS THE OPHEIM AREA THIS
AFTERNOON AND WILL HAVE THE DENSE FOG ADVISORY EXTENDED UNTIL 9
PM. THE NEXT SHIFT CAN MONITOR TRENDS TO BEST DETERMINE IF OR WHEN
FOG MAY LIFT. OTHERWISE EXPECT LOW STRATUS TO CONTINUE TO PLAGUE
THE CWA. WILL CONTINUE WITH SLIGHT CHANCE POPS OVERNIGHT ACROSS
PORTIONS OF THE REGION...FOLLOWING 12Z NAM GUIDANCE IN PARTICULAR.
EXPECT MAINLY LIGHT SNOW OR PERHAPS A MIX WITH FREEZING RAIN BUT
AMOUNTS SHOULD BE QUITE MINIMAL.

A WEAK UPPER SHORTWAVE WILL PASS ACROSS THE REGION ON THURSDAY AND
THURSDAY NIGHT WITH A SHORTWAVE RIDGE BUILDING IN ON FRIDAY. THIS
WILL BRING ABOUT A WIND SHIFT TO THE WEST...HELPING TO REMOVE
POTENTIAL FOR LOW STRATUS AND FOG GRADUALLY WITH TIME. THUS...THE
TREND TOWARD THE END OF THE WEEK WILL BE FOR DRIER CONDITIONS AND
MODERATING TEMPERATURES. MUCH OF NORTHEAST MONTANA WILL SEE HIGHS
BY FRIDAY MARCH ABOVE FREEZING WITH THE EXCEPTION OF DEEPER VALLEY
LOCATIONS AND PLACES ALONG THE CANADIAN BORDER. MALIAWCO


.LONG TERM...FRIDAY NIGHT THROUGH WEDNESDAY...
THE BEST POTENTIAL FOR PRECIPITATION NOW LOOKS TO COME SUNDAY. POPS
WERE RAISED AND THE PRECIPITATION LOOKS TO OCCUR WITH TEMPERATURES
AT OR ABOVE FREEZING BUT THERE WILL BE CONCERNS FOR FREEZING RAIN
AND SOME SNOW. WILL HIGHLIGHT THIS IN AN HAZARDOUS WEATHER OUTLOOK
BUT IT LOOKS TO BE A MARGINAL EVENT AT THIS TIME.

REST OF FORECAST LOOKED GOOD. THERE IS SOME POTENTIAL FOR STRONG NW
WINDS AFTER SUNDAY/S DISTURBANCE PASSES...ABOUT TUESDAY...BUT 850 MB
WINDS ONLY GET TO ABOUT 40 KTS. THEREFORE NOT EXPECTING WIDESPREAD
STRONG WINDS. POSSIBLY ISSUES IN THE NORMALLY WINDY SPOTS (I.E. SE
PHILLIPS COUNTY). TFJ

PREVIOUS DISCUSSION...
THE GENERAL SYNOPTIC FLOW REGIME FOR THE EXTENDED FORECAST PERIOD
WILL BE FROM THE WEST AND NORTHWEST WITH A FEW EMBEDDED SMALL-
SCALE DISTURBANCES EARLY IN THE PERIOD...FOLLOWED BY A LARGER-
SCALE STORM SYSTEM OVER THE REGION TOWARD CHRISTMAS EVE.

FIRST...EARLY SUNDAY MORNING...A SMALL DISTURBANCE EMERGES OVER
THE CANADIAN ROCKIES AND GAINS ENOUGH FORCING AND MOISTURE TO
SQUEEZE OUT SOME LIGHT PRECIPITATION. BASICALLY WENT WITH A MODEL
BLEND HERE...SLIGHTLY FAVORING THE EC FOR ITS RUN TO RUN
CONSISTENCY. NOT EXPECTING MUCH...MAYBE A HALF INCH OF SNOW NORTH
OF THE MISSOURI RIVER AND SOME LIGHT RAIN SOUTH OF THE MISSOURI
RIVER.

MONDAY NIGHT THROUGH WEDNESDAY NIGHT...A STRONGER AND MORE-
ESTABLISHED NORTHWESTERLY FLOW ALOFT SEEMS TO TAKE ROOT OVER THE
REGION AND SETS UP SOME HIGHER ELEVATION AREAS OF CENTRAL MONTANA
WITH OVER-RUNNING AND ACCUMULATING PRECIPITATION. THIS WILL LIKELY
REMAIN CONFINED TO THE NE AND SW CORNERS OF OUR CWA. MODELS
INDICATE THAT THIS PRECIPITATION TREND WILL LATER THE BECOME
ENHANCED BY A COLD AIR MASS...LARGER TROUGH...AND STRONGER STORM
SYSTEM POSSIBLY BY CHRISTMAS TIME. TRIED TO REFLECT THIS THINKING
WITH THE FORECAST GRIDS. BMICKELSON

&&

.AVIATION...
MVFR TO IFR STRATUS WILL CONTINUE OVERNIGHT. ISOLATED SNOW SHOWERS
AND/OR LIGHT FREEZING RAIN WILL NOT BE ENOUGH TO RESTRICT
VISIBILITY OR PRODUCE MEANINGFUL IMPACTS AS AMOUNTS WILL BE
MINIMAL. EXPECT SOUTHEAST WINDS AROUND 10 KTS OVERNIGHT. MALIAWCO

&&

.GLASGOW WATCHES/WARNINGS/ADVISORIES...
DENSE FOG ADVISORY UNTIL 9 PM MST THIS EVENING FOR NORTHERN
VALLEY.

&&

$$

WEATHER.GOV/GLASGOW





000
FXUS65 KGGW 172204
AFDGGW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GLASGOW MT
304 PM MST WED DEC 17 2014

.SHORT TERM...FOR NORTHEAST MONTANA...TONIGHT THROUGH FRIDAY...
PATCHY DENSE FREEZING FOG CONTINUES ACROSS THE OPHEIM AREA THIS
AFTERNOON AND WILL HAVE THE DENSE FOG ADVISORY EXTENDED UNTIL 9
PM. THE NEXT SHIFT CAN MONITOR TRENDS TO BEST DETERMINE IF OR WHEN
FOG MAY LIFT. OTHERWISE EXPECT LOW STRATUS TO CONTINUE TO PLAGUE
THE CWA. WILL CONTINUE WITH SLIGHT CHANCE POPS OVERNIGHT ACROSS
PORTIONS OF THE REGION...FOLLOWING 12Z NAM GUIDANCE IN PARTICULAR.
EXPECT MAINLY LIGHT SNOW OR PERHAPS A MIX WITH FREEZING RAIN BUT
AMOUNTS SHOULD BE QUITE MINIMAL.

A WEAK UPPER SHORTWAVE WILL PASS ACROSS THE REGION ON THURSDAY AND
THURSDAY NIGHT WITH A SHORTWAVE RIDGE BUILDING IN ON FRIDAY. THIS
WILL BRING ABOUT A WIND SHIFT TO THE WEST...HELPING TO REMOVE
POTENTIAL FOR LOW STRATUS AND FOG GRADUALLY WITH TIME. THUS...THE
TREND TOWARD THE END OF THE WEEK WILL BE FOR DRIER CONDITIONS AND
MODERATING TEMPERATURES. MUCH OF NORTHEAST MONTANA WILL SEE HIGHS
BY FRIDAY MARCH ABOVE FREEZING WITH THE EXCEPTION OF DEEPER VALLEY
LOCATIONS AND PLACES ALONG THE CANADIAN BORDER. MALIAWCO


.LONG TERM...FRIDAY NIGHT THROUGH WEDNESDAY...
THE BEST POTENTIAL FOR PRECIPITATION NOW LOOKS TO COME SUNDAY. POPS
WERE RAISED AND THE PRECIPITATION LOOKS TO OCCUR WITH TEMPERATURES
AT OR ABOVE FREEZING BUT THERE WILL BE CONCERNS FOR FREEZING RAIN
AND SOME SNOW. WILL HIGHLIGHT THIS IN AN HAZARDOUS WEATHER OUTLOOK
BUT IT LOOKS TO BE A MARGINAL EVENT AT THIS TIME.

REST OF FORECAST LOOKED GOOD. THERE IS SOME POTENTIAL FOR STRONG NW
WINDS AFTER SUNDAY/S DISTURBANCE PASSES...ABOUT TUESDAY...BUT 850 MB
WINDS ONLY GET TO ABOUT 40 KTS. THEREFORE NOT EXPECTING WIDESPREAD
STRONG WINDS. POSSIBLY ISSUES IN THE NORMALLY WINDY SPOTS (I.E. SE
PHILLIPS COUNTY). TFJ

PREVIOUS DISCUSSION...
THE GENERAL SYNOPTIC FLOW REGIME FOR THE EXTENDED FORECAST PERIOD
WILL BE FROM THE WEST AND NORTHWEST WITH A FEW EMBEDDED SMALL-
SCALE DISTURBANCES EARLY IN THE PERIOD...FOLLOWED BY A LARGER-
SCALE STORM SYSTEM OVER THE REGION TOWARD CHRISTMAS EVE.

FIRST...EARLY SUNDAY MORNING...A SMALL DISTURBANCE EMERGES OVER
THE CANADIAN ROCKIES AND GAINS ENOUGH FORCING AND MOISTURE TO
SQUEEZE OUT SOME LIGHT PRECIPITATION. BASICALLY WENT WITH A MODEL
BLEND HERE...SLIGHTLY FAVORING THE EC FOR ITS RUN TO RUN
CONSISTENCY. NOT EXPECTING MUCH...MAYBE A HALF INCH OF SNOW NORTH
OF THE MISSOURI RIVER AND SOME LIGHT RAIN SOUTH OF THE MISSOURI
RIVER.

MONDAY NIGHT THROUGH WEDNESDAY NIGHT...A STRONGER AND MORE-
ESTABLISHED NORTHWESTERLY FLOW ALOFT SEEMS TO TAKE ROOT OVER THE
REGION AND SETS UP SOME HIGHER ELEVATION AREAS OF CENTRAL MONTANA
WITH OVER-RUNNING AND ACCUMULATING PRECIPITATION. THIS WILL LIKELY
REMAIN CONFINED TO THE NE AND SW CORNERS OF OUR CWA. MODELS
INDICATE THAT THIS PRECIPITATION TREND WILL LATER THE BECOME
ENHANCED BY A COLD AIR MASS...LARGER TROUGH...AND STRONGER STORM
SYSTEM POSSIBLY BY CHRISTMAS TIME. TRIED TO REFLECT THIS THINKING
WITH THE FORECAST GRIDS. BMICKELSON

&&

.AVIATION...
MVFR TO IFR STRATUS WILL CONTINUE OVERNIGHT. ISOLATED SNOW SHOWERS
AND/OR LIGHT FREEZING RAIN WILL NOT BE ENOUGH TO RESTRICT
VISIBILITY OR PRODUCE MEANINGFUL IMPACTS AS AMOUNTS WILL BE
MINIMAL. EXPECT SOUTHEAST WINDS AROUND 10 KTS OVERNIGHT. MALIAWCO

&&

.GLASGOW WATCHES/WARNINGS/ADVISORIES...
DENSE FOG ADVISORY UNTIL 9 PM MST THIS EVENING FOR NORTHERN
VALLEY.

&&

$$

WEATHER.GOV/GLASGOW





000
FXUS65 KBYZ 172131
AFDBYZ

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BILLINGS MT
231 PM MST WED DEC 17 2014

.SHORT TERM...VALID FOR THU AND FRI...

WEAK UPPER LOW PRESSURE SYSTEM WILL MOVE ACROSS NORTHERN MONTANA
TONIGHT AND WILL BRING AREAS OF LIGHT SNOW THIS EVENING ACROSS OUR
NORTHEAST ZONES. SNOW IS EXPECTED TO BE VERY LIGHT WITH NO
ACCUMULATIONS. AS THE LOW MOVES TO OUR EAST TONIGHT...SOME
CLEARING IS EXPECTED ACROSS OUR WESTERN AND CENTRAL ZONES. THIS
WILL ALLOW FOR COOLER OVERNIGHT LOW TEMPERATURES WITH TEENS TO
LOWER 20S. HRRR IS INDICATING FOG TO REDEVELOP OVER SOUTHERN
POWDER RIVER AND CARTER COUNTIES TONIGHT AS LOW LEVEL MOISTURE
REMAINS POOLED OVER THESE AREAS. DID INCLUDED PATCHY FOG FOR
PORTIONS OF SOUTHEAST MONTANA TONIGHT. WEAK SHORT WAVE TO MOVE
THROUGH THURSDAY WHICH WHICH WILL BRING SCATTERED SNOW SHOWERS TO
OUR SOUTHWEST MOUNTAINS. DRY WEATHER AND SLOWLY WARMING
TEMPERATURES WILL CONTINUE INTO FRIDAY AS SHORT WAVE RIDGING MOVES
IN OVER THE REGION. HIGH TEMPERATURES WILL BE IN THE UPPER 30S TO
LOWER 40S BOTH THURSDAY AND FRIDAY. RICHMOND

.LONG TERM...VALID FOR SAT...SUN...MON...TUE...WED...

GUIDANCE CONTINUES TO BE IN GOOD AGREEMENT INTO EARLY NEXT WEEK.
WHILE THE FINER DETAILS MAY DIFFER..THE OVERALL UNSETTLED PATTERN
IN THE EXTENDED CONTINUES. AFTER THE RIDGING FRIDAY...A WEAK
SHORTWAVE WILL CROSS THE STATE...BRING ANOTHER CHANCE FOR LIGHT
PRECIP TO THE MOUNTAINS. UPPER LEVEL FLOW BEGINS TO INCREASE
SATURDAY NIGHT AS A PACIFIC JET STARTS MOVING INTO THE STATE. LEE
SIDE TROUGHING DEVELOPS...WITH A SURFACE LOW DEVELOPING OVER
SOUTHERN ALBERTA. IN RESPONSE...THE PRESSURE GRADIENT TIGHTENS
OVER SOUTHERN MONTANA...RESULTING IN STRONGER WINDS DEVELOPING
FIRST IN THE GAP AREAS...THEN SPREADING OUT TO AROUND BILLINGS.
MEX MOS FOR LIVINGSTON HAS WINDS INCREASING INTO 30 MPH TO NEAR
40 MPH RANGE SUNDAY AFTERNOON. STILL KEEPING GRIDS SUB ADVISORY
GIVEN THIS IS STILL FOUR DAYS OUT...BUT IF CURRENT TRENDS
HOLD...LOOKING AT ANOTHER WIND EVENT DURING THE DAY SUNDAY.

AS THE LOW TRACKS OUT OF CANADA INTO THE NORTHERN PLAINS
MONDAY...A COLD FRONT MOVES THROUGH THE AREA. WITH AMPLE MOISTURE
STILL BRING TRANSPORTED INTO THE AREA...POPS CONTINUE MONDAY INTO
TUESDAY. TEMPERATURES WILL REMAIN RELATIVELY WARM...SO MUCH OF THE
CENTRAL ZONES STILL LOOK TO GET RAIN. FARTHER EAST WARDS MILES
CITY AND BAKER...WHERE TEMPERATURES ARE A BIT COOLER...MAY SEE
SOME FREEZING RAIN. WINDS WILL ALSO BE MORE NORTH WESTERLY...SO
NOT AS MUCH OF AN UP SLOPE FLOW EVENT. THINGS BEGIN TO TAPPER
OFF...WITH TEMPERATURES COOLING BACK INTO THE 30S FOR HIGHS.

LOOKING AHEAD TO CHRISTMAS EVE AND CHRISTMAS...ANOTHER LOW
DEVELOPS AND TRACKS ACROSS MONTANA...GIVING THE AREA A SHOT AT
MORE PRECIP. WITH THE SYSTEM...THE AIR MASS IN PLACE WILL BE
COLDER...WITH 850MB TEMPERATURES BELOW FREEZING. THE THE GFS AND
ECMWF ARE SUGGESTING A SHOT AT A WHITE CHRISTMAS...WILL CONTINUE
TO WATCH THIS. REIMER &&

.AVIATION...

CONDITIONS HAVE IMPROVED THIS AFTERNOON...GENERALLY MVFR TO VFR.
EXPECT FLIGHT CONDITIONS REMAIN VFR/MVFR OVERNIGHT AND INTO
TOMORROW. SOME PATCH FOG WILL BE POSSIBLE SOUTH OF MILES
CITY...BUT WILL LIKELY NOT IMPACT ANY TERMINALS. WITH SOME MID LEVEL
CLOUDS...SOME MOUNTAIN OBSCURATION WILL CONTINUE TO BE POSSIBLE.
REIMER
&&

.PRELIMINARY POINT TEMP/POPS...

    THU     FRI     SAT     SUN     MON     TUE     WED
-----------------------------------------------------------
BIL 023/038 023/038 027/041 027/046 033/045 026/038 022/033
    00/B    00/B    11/B    13/W    32/W    21/N    23/J
LVM 022/042 024/040 027/043 028/046 035/045 022/039 023/035
    01/N    11/N    21/B    24/W    43/W    21/N    33/J
HDN 013/037 015/037 020/040 021/044 029/043 021/037 020/034
    10/B    00/B    01/B    13/W    33/W    21/B    22/J
MLS 017/038 019/037 021/040 022/042 029/040 025/036 020/031
    20/B    00/B    11/B    13/W    22/W    11/B    11/E
4BQ 015/041 017/040 019/041 022/044 030/042 024/037 019/033
    20/B    00/B    11/B    12/W    23/W    21/B    22/J
BHK 015/036 019/037 019/040 021/042 026/037 021/033 017/027
    20/B    10/B    01/B    02/W    22/W    11/N    11/B
SHR 015/041 015/038 020/040 019/043 030/042 022/037 019/033
    10/B    10/B    11/B    13/W    34/W    32/J    22/J

&&

.BYZ WATCHES/WARNINGS/ADVISORIES...
MT...NONE.
WY...NONE.

&&

$$
WEATHER.GOV/BILLINGS



000
FXUS65 KBYZ 172131
AFDBYZ

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BILLINGS MT
231 PM MST WED DEC 17 2014

.SHORT TERM...VALID FOR THU AND FRI...

WEAK UPPER LOW PRESSURE SYSTEM WILL MOVE ACROSS NORTHERN MONTANA
TONIGHT AND WILL BRING AREAS OF LIGHT SNOW THIS EVENING ACROSS OUR
NORTHEAST ZONES. SNOW IS EXPECTED TO BE VERY LIGHT WITH NO
ACCUMULATIONS. AS THE LOW MOVES TO OUR EAST TONIGHT...SOME
CLEARING IS EXPECTED ACROSS OUR WESTERN AND CENTRAL ZONES. THIS
WILL ALLOW FOR COOLER OVERNIGHT LOW TEMPERATURES WITH TEENS TO
LOWER 20S. HRRR IS INDICATING FOG TO REDEVELOP OVER SOUTHERN
POWDER RIVER AND CARTER COUNTIES TONIGHT AS LOW LEVEL MOISTURE
REMAINS POOLED OVER THESE AREAS. DID INCLUDED PATCHY FOG FOR
PORTIONS OF SOUTHEAST MONTANA TONIGHT. WEAK SHORT WAVE TO MOVE
THROUGH THURSDAY WHICH WHICH WILL BRING SCATTERED SNOW SHOWERS TO
OUR SOUTHWEST MOUNTAINS. DRY WEATHER AND SLOWLY WARMING
TEMPERATURES WILL CONTINUE INTO FRIDAY AS SHORT WAVE RIDGING MOVES
IN OVER THE REGION. HIGH TEMPERATURES WILL BE IN THE UPPER 30S TO
LOWER 40S BOTH THURSDAY AND FRIDAY. RICHMOND

.LONG TERM...VALID FOR SAT...SUN...MON...TUE...WED...

GUIDANCE CONTINUES TO BE IN GOOD AGREEMENT INTO EARLY NEXT WEEK.
WHILE THE FINER DETAILS MAY DIFFER..THE OVERALL UNSETTLED PATTERN
IN THE EXTENDED CONTINUES. AFTER THE RIDGING FRIDAY...A WEAK
SHORTWAVE WILL CROSS THE STATE...BRING ANOTHER CHANCE FOR LIGHT
PRECIP TO THE MOUNTAINS. UPPER LEVEL FLOW BEGINS TO INCREASE
SATURDAY NIGHT AS A PACIFIC JET STARTS MOVING INTO THE STATE. LEE
SIDE TROUGHING DEVELOPS...WITH A SURFACE LOW DEVELOPING OVER
SOUTHERN ALBERTA. IN RESPONSE...THE PRESSURE GRADIENT TIGHTENS
OVER SOUTHERN MONTANA...RESULTING IN STRONGER WINDS DEVELOPING
FIRST IN THE GAP AREAS...THEN SPREADING OUT TO AROUND BILLINGS.
MEX MOS FOR LIVINGSTON HAS WINDS INCREASING INTO 30 MPH TO NEAR
40 MPH RANGE SUNDAY AFTERNOON. STILL KEEPING GRIDS SUB ADVISORY
GIVEN THIS IS STILL FOUR DAYS OUT...BUT IF CURRENT TRENDS
HOLD...LOOKING AT ANOTHER WIND EVENT DURING THE DAY SUNDAY.

AS THE LOW TRACKS OUT OF CANADA INTO THE NORTHERN PLAINS
MONDAY...A COLD FRONT MOVES THROUGH THE AREA. WITH AMPLE MOISTURE
STILL BRING TRANSPORTED INTO THE AREA...POPS CONTINUE MONDAY INTO
TUESDAY. TEMPERATURES WILL REMAIN RELATIVELY WARM...SO MUCH OF THE
CENTRAL ZONES STILL LOOK TO GET RAIN. FARTHER EAST WARDS MILES
CITY AND BAKER...WHERE TEMPERATURES ARE A BIT COOLER...MAY SEE
SOME FREEZING RAIN. WINDS WILL ALSO BE MORE NORTH WESTERLY...SO
NOT AS MUCH OF AN UP SLOPE FLOW EVENT. THINGS BEGIN TO TAPPER
OFF...WITH TEMPERATURES COOLING BACK INTO THE 30S FOR HIGHS.

LOOKING AHEAD TO CHRISTMAS EVE AND CHRISTMAS...ANOTHER LOW
DEVELOPS AND TRACKS ACROSS MONTANA...GIVING THE AREA A SHOT AT
MORE PRECIP. WITH THE SYSTEM...THE AIR MASS IN PLACE WILL BE
COLDER...WITH 850MB TEMPERATURES BELOW FREEZING. THE THE GFS AND
ECMWF ARE SUGGESTING A SHOT AT A WHITE CHRISTMAS...WILL CONTINUE
TO WATCH THIS. REIMER &&

.AVIATION...

CONDITIONS HAVE IMPROVED THIS AFTERNOON...GENERALLY MVFR TO VFR.
EXPECT FLIGHT CONDITIONS REMAIN VFR/MVFR OVERNIGHT AND INTO
TOMORROW. SOME PATCH FOG WILL BE POSSIBLE SOUTH OF MILES
CITY...BUT WILL LIKELY NOT IMPACT ANY TERMINALS. WITH SOME MID LEVEL
CLOUDS...SOME MOUNTAIN OBSCURATION WILL CONTINUE TO BE POSSIBLE.
REIMER
&&

.PRELIMINARY POINT TEMP/POPS...

    THU     FRI     SAT     SUN     MON     TUE     WED
-----------------------------------------------------------
BIL 023/038 023/038 027/041 027/046 033/045 026/038 022/033
    00/B    00/B    11/B    13/W    32/W    21/N    23/J
LVM 022/042 024/040 027/043 028/046 035/045 022/039 023/035
    01/N    11/N    21/B    24/W    43/W    21/N    33/J
HDN 013/037 015/037 020/040 021/044 029/043 021/037 020/034
    10/B    00/B    01/B    13/W    33/W    21/B    22/J
MLS 017/038 019/037 021/040 022/042 029/040 025/036 020/031
    20/B    00/B    11/B    13/W    22/W    11/B    11/E
4BQ 015/041 017/040 019/041 022/044 030/042 024/037 019/033
    20/B    00/B    11/B    12/W    23/W    21/B    22/J
BHK 015/036 019/037 019/040 021/042 026/037 021/033 017/027
    20/B    10/B    01/B    02/W    22/W    11/N    11/B
SHR 015/041 015/038 020/040 019/043 030/042 022/037 019/033
    10/B    10/B    11/B    13/W    34/W    32/J    22/J

&&

.BYZ WATCHES/WARNINGS/ADVISORIES...
MT...NONE.
WY...NONE.

&&

$$
WEATHER.GOV/BILLINGS



000
FXUS65 KBYZ 172131
AFDBYZ

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BILLINGS MT
231 PM MST WED DEC 17 2014

.SHORT TERM...VALID FOR THU AND FRI...

WEAK UPPER LOW PRESSURE SYSTEM WILL MOVE ACROSS NORTHERN MONTANA
TONIGHT AND WILL BRING AREAS OF LIGHT SNOW THIS EVENING ACROSS OUR
NORTHEAST ZONES. SNOW IS EXPECTED TO BE VERY LIGHT WITH NO
ACCUMULATIONS. AS THE LOW MOVES TO OUR EAST TONIGHT...SOME
CLEARING IS EXPECTED ACROSS OUR WESTERN AND CENTRAL ZONES. THIS
WILL ALLOW FOR COOLER OVERNIGHT LOW TEMPERATURES WITH TEENS TO
LOWER 20S. HRRR IS INDICATING FOG TO REDEVELOP OVER SOUTHERN
POWDER RIVER AND CARTER COUNTIES TONIGHT AS LOW LEVEL MOISTURE
REMAINS POOLED OVER THESE AREAS. DID INCLUDED PATCHY FOG FOR
PORTIONS OF SOUTHEAST MONTANA TONIGHT. WEAK SHORT WAVE TO MOVE
THROUGH THURSDAY WHICH WHICH WILL BRING SCATTERED SNOW SHOWERS TO
OUR SOUTHWEST MOUNTAINS. DRY WEATHER AND SLOWLY WARMING
TEMPERATURES WILL CONTINUE INTO FRIDAY AS SHORT WAVE RIDGING MOVES
IN OVER THE REGION. HIGH TEMPERATURES WILL BE IN THE UPPER 30S TO
LOWER 40S BOTH THURSDAY AND FRIDAY. RICHMOND

.LONG TERM...VALID FOR SAT...SUN...MON...TUE...WED...

GUIDANCE CONTINUES TO BE IN GOOD AGREEMENT INTO EARLY NEXT WEEK.
WHILE THE FINER DETAILS MAY DIFFER..THE OVERALL UNSETTLED PATTERN
IN THE EXTENDED CONTINUES. AFTER THE RIDGING FRIDAY...A WEAK
SHORTWAVE WILL CROSS THE STATE...BRING ANOTHER CHANCE FOR LIGHT
PRECIP TO THE MOUNTAINS. UPPER LEVEL FLOW BEGINS TO INCREASE
SATURDAY NIGHT AS A PACIFIC JET STARTS MOVING INTO THE STATE. LEE
SIDE TROUGHING DEVELOPS...WITH A SURFACE LOW DEVELOPING OVER
SOUTHERN ALBERTA. IN RESPONSE...THE PRESSURE GRADIENT TIGHTENS
OVER SOUTHERN MONTANA...RESULTING IN STRONGER WINDS DEVELOPING
FIRST IN THE GAP AREAS...THEN SPREADING OUT TO AROUND BILLINGS.
MEX MOS FOR LIVINGSTON HAS WINDS INCREASING INTO 30 MPH TO NEAR
40 MPH RANGE SUNDAY AFTERNOON. STILL KEEPING GRIDS SUB ADVISORY
GIVEN THIS IS STILL FOUR DAYS OUT...BUT IF CURRENT TRENDS
HOLD...LOOKING AT ANOTHER WIND EVENT DURING THE DAY SUNDAY.

AS THE LOW TRACKS OUT OF CANADA INTO THE NORTHERN PLAINS
MONDAY...A COLD FRONT MOVES THROUGH THE AREA. WITH AMPLE MOISTURE
STILL BRING TRANSPORTED INTO THE AREA...POPS CONTINUE MONDAY INTO
TUESDAY. TEMPERATURES WILL REMAIN RELATIVELY WARM...SO MUCH OF THE
CENTRAL ZONES STILL LOOK TO GET RAIN. FARTHER EAST WARDS MILES
CITY AND BAKER...WHERE TEMPERATURES ARE A BIT COOLER...MAY SEE
SOME FREEZING RAIN. WINDS WILL ALSO BE MORE NORTH WESTERLY...SO
NOT AS MUCH OF AN UP SLOPE FLOW EVENT. THINGS BEGIN TO TAPPER
OFF...WITH TEMPERATURES COOLING BACK INTO THE 30S FOR HIGHS.

LOOKING AHEAD TO CHRISTMAS EVE AND CHRISTMAS...ANOTHER LOW
DEVELOPS AND TRACKS ACROSS MONTANA...GIVING THE AREA A SHOT AT
MORE PRECIP. WITH THE SYSTEM...THE AIR MASS IN PLACE WILL BE
COLDER...WITH 850MB TEMPERATURES BELOW FREEZING. THE THE GFS AND
ECMWF ARE SUGGESTING A SHOT AT A WHITE CHRISTMAS...WILL CONTINUE
TO WATCH THIS. REIMER &&

.AVIATION...

CONDITIONS HAVE IMPROVED THIS AFTERNOON...GENERALLY MVFR TO VFR.
EXPECT FLIGHT CONDITIONS REMAIN VFR/MVFR OVERNIGHT AND INTO
TOMORROW. SOME PATCH FOG WILL BE POSSIBLE SOUTH OF MILES
CITY...BUT WILL LIKELY NOT IMPACT ANY TERMINALS. WITH SOME MID LEVEL
CLOUDS...SOME MOUNTAIN OBSCURATION WILL CONTINUE TO BE POSSIBLE.
REIMER
&&

.PRELIMINARY POINT TEMP/POPS...

    THU     FRI     SAT     SUN     MON     TUE     WED
-----------------------------------------------------------
BIL 023/038 023/038 027/041 027/046 033/045 026/038 022/033
    00/B    00/B    11/B    13/W    32/W    21/N    23/J
LVM 022/042 024/040 027/043 028/046 035/045 022/039 023/035
    01/N    11/N    21/B    24/W    43/W    21/N    33/J
HDN 013/037 015/037 020/040 021/044 029/043 021/037 020/034
    10/B    00/B    01/B    13/W    33/W    21/B    22/J
MLS 017/038 019/037 021/040 022/042 029/040 025/036 020/031
    20/B    00/B    11/B    13/W    22/W    11/B    11/E
4BQ 015/041 017/040 019/041 022/044 030/042 024/037 019/033
    20/B    00/B    11/B    12/W    23/W    21/B    22/J
BHK 015/036 019/037 019/040 021/042 026/037 021/033 017/027
    20/B    10/B    01/B    02/W    22/W    11/N    11/B
SHR 015/041 015/038 020/040 019/043 030/042 022/037 019/033
    10/B    10/B    11/B    13/W    34/W    32/J    22/J

&&

.BYZ WATCHES/WARNINGS/ADVISORIES...
MT...NONE.
WY...NONE.

&&

$$
WEATHER.GOV/BILLINGS



000
FXUS65 KBYZ 172131
AFDBYZ

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BILLINGS MT
231 PM MST WED DEC 17 2014

.SHORT TERM...VALID FOR THU AND FRI...

WEAK UPPER LOW PRESSURE SYSTEM WILL MOVE ACROSS NORTHERN MONTANA
TONIGHT AND WILL BRING AREAS OF LIGHT SNOW THIS EVENING ACROSS OUR
NORTHEAST ZONES. SNOW IS EXPECTED TO BE VERY LIGHT WITH NO
ACCUMULATIONS. AS THE LOW MOVES TO OUR EAST TONIGHT...SOME
CLEARING IS EXPECTED ACROSS OUR WESTERN AND CENTRAL ZONES. THIS
WILL ALLOW FOR COOLER OVERNIGHT LOW TEMPERATURES WITH TEENS TO
LOWER 20S. HRRR IS INDICATING FOG TO REDEVELOP OVER SOUTHERN
POWDER RIVER AND CARTER COUNTIES TONIGHT AS LOW LEVEL MOISTURE
REMAINS POOLED OVER THESE AREAS. DID INCLUDED PATCHY FOG FOR
PORTIONS OF SOUTHEAST MONTANA TONIGHT. WEAK SHORT WAVE TO MOVE
THROUGH THURSDAY WHICH WHICH WILL BRING SCATTERED SNOW SHOWERS TO
OUR SOUTHWEST MOUNTAINS. DRY WEATHER AND SLOWLY WARMING
TEMPERATURES WILL CONTINUE INTO FRIDAY AS SHORT WAVE RIDGING MOVES
IN OVER THE REGION. HIGH TEMPERATURES WILL BE IN THE UPPER 30S TO
LOWER 40S BOTH THURSDAY AND FRIDAY. RICHMOND

.LONG TERM...VALID FOR SAT...SUN...MON...TUE...WED...

GUIDANCE CONTINUES TO BE IN GOOD AGREEMENT INTO EARLY NEXT WEEK.
WHILE THE FINER DETAILS MAY DIFFER..THE OVERALL UNSETTLED PATTERN
IN THE EXTENDED CONTINUES. AFTER THE RIDGING FRIDAY...A WEAK
SHORTWAVE WILL CROSS THE STATE...BRING ANOTHER CHANCE FOR LIGHT
PRECIP TO THE MOUNTAINS. UPPER LEVEL FLOW BEGINS TO INCREASE
SATURDAY NIGHT AS A PACIFIC JET STARTS MOVING INTO THE STATE. LEE
SIDE TROUGHING DEVELOPS...WITH A SURFACE LOW DEVELOPING OVER
SOUTHERN ALBERTA. IN RESPONSE...THE PRESSURE GRADIENT TIGHTENS
OVER SOUTHERN MONTANA...RESULTING IN STRONGER WINDS DEVELOPING
FIRST IN THE GAP AREAS...THEN SPREADING OUT TO AROUND BILLINGS.
MEX MOS FOR LIVINGSTON HAS WINDS INCREASING INTO 30 MPH TO NEAR
40 MPH RANGE SUNDAY AFTERNOON. STILL KEEPING GRIDS SUB ADVISORY
GIVEN THIS IS STILL FOUR DAYS OUT...BUT IF CURRENT TRENDS
HOLD...LOOKING AT ANOTHER WIND EVENT DURING THE DAY SUNDAY.

AS THE LOW TRACKS OUT OF CANADA INTO THE NORTHERN PLAINS
MONDAY...A COLD FRONT MOVES THROUGH THE AREA. WITH AMPLE MOISTURE
STILL BRING TRANSPORTED INTO THE AREA...POPS CONTINUE MONDAY INTO
TUESDAY. TEMPERATURES WILL REMAIN RELATIVELY WARM...SO MUCH OF THE
CENTRAL ZONES STILL LOOK TO GET RAIN. FARTHER EAST WARDS MILES
CITY AND BAKER...WHERE TEMPERATURES ARE A BIT COOLER...MAY SEE
SOME FREEZING RAIN. WINDS WILL ALSO BE MORE NORTH WESTERLY...SO
NOT AS MUCH OF AN UP SLOPE FLOW EVENT. THINGS BEGIN TO TAPPER
OFF...WITH TEMPERATURES COOLING BACK INTO THE 30S FOR HIGHS.

LOOKING AHEAD TO CHRISTMAS EVE AND CHRISTMAS...ANOTHER LOW
DEVELOPS AND TRACKS ACROSS MONTANA...GIVING THE AREA A SHOT AT
MORE PRECIP. WITH THE SYSTEM...THE AIR MASS IN PLACE WILL BE
COLDER...WITH 850MB TEMPERATURES BELOW FREEZING. THE THE GFS AND
ECMWF ARE SUGGESTING A SHOT AT A WHITE CHRISTMAS...WILL CONTINUE
TO WATCH THIS. REIMER &&

.AVIATION...

CONDITIONS HAVE IMPROVED THIS AFTERNOON...GENERALLY MVFR TO VFR.
EXPECT FLIGHT CONDITIONS REMAIN VFR/MVFR OVERNIGHT AND INTO
TOMORROW. SOME PATCH FOG WILL BE POSSIBLE SOUTH OF MILES
CITY...BUT WILL LIKELY NOT IMPACT ANY TERMINALS. WITH SOME MID LEVEL
CLOUDS...SOME MOUNTAIN OBSCURATION WILL CONTINUE TO BE POSSIBLE.
REIMER
&&

.PRELIMINARY POINT TEMP/POPS...

    THU     FRI     SAT     SUN     MON     TUE     WED
-----------------------------------------------------------
BIL 023/038 023/038 027/041 027/046 033/045 026/038 022/033
    00/B    00/B    11/B    13/W    32/W    21/N    23/J
LVM 022/042 024/040 027/043 028/046 035/045 022/039 023/035
    01/N    11/N    21/B    24/W    43/W    21/N    33/J
HDN 013/037 015/037 020/040 021/044 029/043 021/037 020/034
    10/B    00/B    01/B    13/W    33/W    21/B    22/J
MLS 017/038 019/037 021/040 022/042 029/040 025/036 020/031
    20/B    00/B    11/B    13/W    22/W    11/B    11/E
4BQ 015/041 017/040 019/041 022/044 030/042 024/037 019/033
    20/B    00/B    11/B    12/W    23/W    21/B    22/J
BHK 015/036 019/037 019/040 021/042 026/037 021/033 017/027
    20/B    10/B    01/B    02/W    22/W    11/N    11/B
SHR 015/041 015/038 020/040 019/043 030/042 022/037 019/033
    10/B    10/B    11/B    13/W    34/W    32/J    22/J

&&

.BYZ WATCHES/WARNINGS/ADVISORIES...
MT...NONE.
WY...NONE.

&&

$$
WEATHER.GOV/BILLINGS


  [top]

000
FXUS65 KMSO 172131
AFDMSO

Area Forecast Discussion
National Weather Service Missoula MT
231 PM MST WED DEC 17 2014

...SNOW TURNING TO HEAVY RAIN THIS WEEKEND IN CENTRAL IDAHO...

.DISCUSSION...For the end of the work week, two weakening weather
systems will move through north central Idaho and western
Montana. The first shortwave will impact far northwest Montana
late tonight into Thursday. Due to weak forcing, snowfall totals
are expected to be under an inch for all but the highest terrain.

A more substantial system moves in Friday morning bringing
accumulating snowfall to the passes between Montana and Idaho,
especially Lookout and Lolo passes, each of which could see 2 to
3 inches. As it`s predecessor, this system loses steam as it
crosses western Montana, and valley locations should expect only
light rain.

Saturday night through Monday morning an atmospheric river will
impact central Idaho and western Montana. Snow levels will start
out around 3000 ft Saturday afternoon and rise to around 5000 -
6000 feet by Sunday night. As the forecast stands, this will cause
3 to 7 inches of heavy wet snow by Sunday morning to impact
mountain passes. Lookout and Lolo passes will be most affected,
with snow on the lower end of the range affecting Marias and Lost
Trail passes. While forecast confidence is high with the timing
and high moisture for this system, it is not as good with the snow
levels, and as a result confidence is below average for the snow
amounts at the passes.

During the day Sunday, snow levels will rise causing snow to turn
to rain in many areas, generally causing uncleared roads to be a
wet slushy mess. By Monday, 2 to 3 inches of rain is expected in
the Clearwater Mountains and Bitterroot mountains of central
Idaho. The excessive rain combined with temperatures around
freezing will make falling rocks and debris on roads a risk,
especially along highway 12 in central Idaho.

The rest of the week looks showery with the next significant
disturbance coming in around Christmas. This will be a much cooler
system that will likely cause some snow and travel difficulties.
There is a lot of uncertainty associated with the strength and
timing of this system, but models across the board have been
consistent in bringing something through around Christmas. So the
odds of a white Christmas are improving!

&&

.AVIATION...Satellite imagery shows high and mid-level clouds
moving into the area, and this trend is expected to continue
through the rest of the evening. Currently northwest Montana has
the best chance of seeing precipitation in the next 24 hours.
Models depict intermittent snow starting at KGPI around 18/1200Z,however,
accumulations are below an inch.

&&

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

$$




000
FXUS65 KMSO 172131
AFDMSO

Area Forecast Discussion
National Weather Service Missoula MT
231 PM MST WED DEC 17 2014

...SNOW TURNING TO HEAVY RAIN THIS WEEKEND IN CENTRAL IDAHO...

.DISCUSSION...For the end of the work week, two weakening weather
systems will move through north central Idaho and western
Montana. The first shortwave will impact far northwest Montana
late tonight into Thursday. Due to weak forcing, snowfall totals
are expected to be under an inch for all but the highest terrain.

A more substantial system moves in Friday morning bringing
accumulating snowfall to the passes between Montana and Idaho,
especially Lookout and Lolo passes, each of which could see 2 to
3 inches. As it`s predecessor, this system loses steam as it
crosses western Montana, and valley locations should expect only
light rain.

Saturday night through Monday morning an atmospheric river will
impact central Idaho and western Montana. Snow levels will start
out around 3000 ft Saturday afternoon and rise to around 5000 -
6000 feet by Sunday night. As the forecast stands, this will cause
3 to 7 inches of heavy wet snow by Sunday morning to impact
mountain passes. Lookout and Lolo passes will be most affected,
with snow on the lower end of the range affecting Marias and Lost
Trail passes. While forecast confidence is high with the timing
and high moisture for this system, it is not as good with the snow
levels, and as a result confidence is below average for the snow
amounts at the passes.

During the day Sunday, snow levels will rise causing snow to turn
to rain in many areas, generally causing uncleared roads to be a
wet slushy mess. By Monday, 2 to 3 inches of rain is expected in
the Clearwater Mountains and Bitterroot mountains of central
Idaho. The excessive rain combined with temperatures around
freezing will make falling rocks and debris on roads a risk,
especially along highway 12 in central Idaho.

The rest of the week looks showery with the next significant
disturbance coming in around Christmas. This will be a much cooler
system that will likely cause some snow and travel difficulties.
There is a lot of uncertainty associated with the strength and
timing of this system, but models across the board have been
consistent in bringing something through around Christmas. So the
odds of a white Christmas are improving!

&&

.AVIATION...Satellite imagery shows high and mid-level clouds
moving into the area, and this trend is expected to continue
through the rest of the evening. Currently northwest Montana has
the best chance of seeing precipitation in the next 24 hours.
Models depict intermittent snow starting at KGPI around 18/1200Z,however,
accumulations are below an inch.

&&

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

$$





000
FXUS65 KTFX 172122
AFDTFX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREAT FALLS MT
222 PM MST Wed Dec 17 2014

.DISCUSSION...
Wednesday night through Friday...A rather quiet and cool end to
the work week is expected as no major systems are expected to move
over the area in this time frame. Temperatures will remain near
seasonal values as weak shortwave toughing on Thursday will be
followed by a week shortwave ridge on Friday. The biggest impact
during this time period will be the persistent freezing fog over
parts of Central and North Central Montana. Have extended the
advisory currently in effect until 9 pm for areas around Cut Bank
and Shelby. Westerly winds should develop around 6 pm and
eventual scour out the fog. However, there is a chance that the
nocturnal boundary layer will strengthen the inversion and will
limit any potential for the west winds to move the fog out of the
area until Thursday when a weak shortwave moves through the area.
Widespread moisture is not expected at this time with this
disturbance...however some isolated mountain snow showers are
possible. Suk

Friday Night through Wednesday...A weak shortwave trough will move
through Montana Friday night into Saturday, bringing just a chance
of snow to the mountains. Forecast models continue to indicate
that the pattern will then change for Saturday night through
Tuesday. An upper level high pressure ridge will strengthen off
the California coast and a low pressure trough will deepen from
Hudson Bay into the Great Lakes. This will result in Montana being
under a strong northwesterly flow aloft. The models indicate that
the strongest winds aloft will occur Sunday into Sunday night with
the passage of a disturbance embedded in the flow. However, the
models differ on just how strong these winds will be. The ECMWF
only forecasts winds of 45 to 55 kts at 700 mb, while the GFS
generally has 60 to 70 kt winds. Have therefore used a compromise
solution between these two models with regards to surface wind
strength. Despite this difference, this set-up will bring gusty
westerly downslope winds to much of the area, but especially over
the plains of north central Montana. In fact, some areas along the
Rocky Mountain Front could approach High Wind criteria (40 mph
sustained/58 mph gusts). Confidence remains moderate that High
Wind highlights may be needed for this event. The only concern is
that the northwesterly wind direction is not as favorable for
widespread High Winds. There is also significant moisture with
this disturbance, so have continued to spread the chance for
precipitation out onto the plains. Winds aloft will decrease
somewhat after the passage of the disturbance, but the
northwesterly flow aloft will remain fairly moist, so have kept
the chance for precipitation above climatological normals across
the area into Tuesday. A potentially significant weather system
originating in the Gulf of Alaska is then forecast to move into
Montana Tuesday into Wednesday, bringing a very good chance of
precipitation. Because this feature is near the end of the period,
exact timing and types of precipitation are very uncertain.
Regardless, this system will need to be monitored for potential
winter weather highlights, especially considering that it would be
moving into the area during peak holiday travel time. The breezy
winds through Monday will keep temperatures around 10 degrees
above normal. The warmest day of the period appears to be Monday,
when most lower elevation locations should get well into the 40s.
However, with the system moving into the area at the end of the
period, temperatures will likely fall back to near or slightly
below seasonal averages by Wednesday. Coulston

&&

.AVIATION...
UPDATED 1758Z.
Light snow will be ending at KHVR and KLWT by late afternoon with
conditions improving to VFR. At KCTB LIFR conditions in freezing fog
will also improve to VFR by late afternoon. Local MVFR visibilities
in freezing fog over southwest Montana will end by mid-afternoon.
For tonight through Thursday morning expect scattered snow over the
Rocky Mountain Front. For tonight into early Thursday morning for
KCTB and KLWT some guidance suggests IFR ceilings and/or
visibilities in freezing fog could return but think there will be
enough wind to prevent this from happening so did not mention in
their TAFs. At KHVR IFR ceilings and/or visibilities in freezing fog
could also return but think there is a better chance there relative
to KLWT/KCTB so included in their taf. But some guidance keeps
conditions VFR at KHVR. For late tonight think southwest winds will
dissipate the freezing fog at KHVR but should southwest winds not
develop IFR conditions could linger into Thursday morning.

&&

.PRELIMINARY POINT TEMPS/POPS...
GTF  23  40  26  40 /  10  10  10  10
CTB  21  39  24  39 /  10  10  10  10
HLN  18  34  19  35 /  10  20  10  20
BZN  14  30  15  32 /  10  10  10  20
WEY  16  32  19  33 /  20  20  30  40
DLN  17  34  19  37 /  10  20  10  20
HVR  18  37  22  39 /  10  10  10  10
LWT  21  43  24  43 /  10  10  10  10

&&

.TFX WATCHES/WARNINGS/ADVISORIES...
FREEZING FOG ADVISORY until 9 PM MST this evening Eastern
Glacier...Toole.

&&

$$

weather.gov/greatfalls
www.twitter.com/NWSGreatFalls
www.facebook.com/NWSGreatFalls





000
FXUS65 KTFX 171759
AFDTFX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREAT FALLS MT
1058 AM MST Wed Dec 17 2014

UPDATED AVIATION DISCUSSION

.UPDATE...
Have continued to decrease the area of the freezing fog advisory.
Have also lowered high temperatures where the freezing fog is
persisting and already keeping locations cooler than previous
forecast. Otherwise no significant changes to the forecast this
morning. Suk


&&

.AVIATION...
UPDATED 1758Z.
Light snow will be ending at KHVR and KLWT by late afternoon with
conditions improving to VFR. At KCTB LIFR conditions in freezing fog
will also improve to VFR by late afternoon. Local MVFR visibilities
in freezing fog over southwest Montana will end by mid-afternoon.
For tonight through Thursday morning expect scattered snow over the
Rocky Mountain Front. For tonight into early Thursday morning for
KCTB and KLWT some guidance suggests IFR ceilings and/or
visibilities in freezing fog could return but think there will be
enough wind to prevent this from happening so did not mention in
their TAFs. At KHVR IFR ceilings and/or visibilities in freezing fog
could also return but think there is a better chance there relative
to KLWT/KCTB so included in their taf. But some guidance keeps
conditions VFR at KHVR. For late tonight think southwest winds will
dissipate the freezing fog at KHVR but should southwest winds not
develop IFR conditions could linger into Thursday morning.

&&

.PREV DISCUSSION...
/ISSUED 807 AM MST Wed Dec 17 2014/
FXUS65 KTFX 171507
AFDTFX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREAT FALLS MT
807 AM MST Wed Dec 17 2014

UPDATE...
Dense freezing fog is no longer expected over Cascade and Judith
Basin Counties so the freezing fog advisory for those counties has
been canceled.

&&

.PREV DISCUSSION...
/ISSUED 510 AM MST Wed Dec 17 2014/

Tonight through Friday...Central Montana is underneath an area of
weak cyclonic flow aloft. Precipitation associated with a
disturbance in this flow will move east of the zones today. A weak
trof over over the Eastern Pacific will move over the Pacific
Northwest today and the zones will be underneath the southwest flow
ahead of this system. Flow aloft and dynamics will remain weak,
however. Models show very little warming of the airmass yet raise
temperatures from yesterday. With cloud cover and, possibly, areas
of fog, not convinced that all of that warming will occur and will
moderate high temps somewhat. The airmass will remain unsettled
Thursday as the trof over the Eastern Pacific slowly moves east and
and approaches the zones. Little chance of precipitation is expected
with this system. The Rockies and mountains of Southwest Montana
will have the best chance for snow although accumulations will
remain low. Zelzer

Friday Night through Wednesday...A weak shortwave trough will move
through Montana Friday night into Saturday, bringing just a chance
of snow to the mountains. Forecast models continue to indicate that
the pattern will then change for Saturday night through Tuesday. An
upper level high pressure ridge will strengthen off the California
coast and a low pressure trough will deepen from Hudson Bay into the
Great Lakes. This will result in Montana being under a strong
northwesterly flow aloft. The models indicate that the strongest
winds aloft will occur Sunday into Sunday night with the passage of
a disturbance embedded in the flow. However, the models differ on
just how strong these winds will be. The ECMWF only forecasts winds
of 45 to 55 kts at 700 mb, while the GFS generally has 60 to 70 kt
winds. Have therefore used a compromise solution between these two
models with regards to surface wind strength. Despite this
difference, this set-up will bring gusty westerly downslope winds to
much of the area, but especially over the plains of north central
Montana. In fact, some areas along the Rocky Mountain Front could
approach High Wind criteria (40 mph sustained/58 mph gusts).
Confidence remains moderate that High Wind highlights may be needed
for this event. The only concern is that the northwesterly wind
direction is not as favorable for widespread High Winds. There is
also significant moisture with this disturbance, so have continued
to spread the chance for precipitation out onto the plains. Winds
aloft will decrease somewhat after the passage of the disturbance,
but the northwesterly flow aloft will remain fairly moist, so have
kept the chance for precipitation above climatological normals
across the area into Tuesday. A potentially significant weather
system originating in the Gulf of Alaska is then forecast to move
into Montana Tuesday into Wednesday, bringing a very good chance of
precipitation. Because this feature is near the end of the period,
exact timing and types of precipitation are very uncertain.
Regardless, this system will need to be monitored for potential
winter weather highlights, especially considering that it would be
moving into the area during peak holiday travel time. The breezy
winds through Monday will keep temperatures around 10 degrees above
normal. The warmest day of the period appears to be Monday, when
most lower elevation locations should get well into the 40s.
However, with the system moving into the area at the end of the
period, temperatures will likely fall back to near or slightly below
seasonal averages by Wednesday.
Coulston

&&

.PRELIMINARY POINT TEMPS/POPS...
GTF  35  24  38  26 /  20  10  10  10
CTB  26  21  37  24 /  10  10  10  10
HLN  33  17  33  19 /  20  10  20  10
BZN  28  12  30  14 /  40  10  10  10
WEY  32  16  30  18 /  30  20  20  20
DLN  31  16  33  19 /  10  10  20  10
HVR  29  19  36  21 /  30  10  10  10
LWT  36  22  41  24 /  40  10  10  10

&&

.TFX WATCHES/WARNINGS/ADVISORIES...
FREEZING FOG ADVISORY until 11 AM MST this morning Eastern
Glacier...Toole.

&&

$$

weather.gov/greatfalls
www.twitter.com/NWSGreatFalls
www.facebook.com/NWSGreatFalls








000
FXUS65 KTFX 171759
AFDTFX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREAT FALLS MT
1058 AM MST Wed Dec 17 2014

UPDATED AVIATION DISCUSSION

.UPDATE...
Have continued to decrease the area of the freezing fog advisory.
Have also lowered high temperatures where the freezing fog is
persisting and already keeping locations cooler than previous
forecast. Otherwise no significant changes to the forecast this
morning. Suk


&&

.AVIATION...
UPDATED 1758Z.
Light snow will be ending at KHVR and KLWT by late afternoon with
conditions improving to VFR. At KCTB LIFR conditions in freezing fog
will also improve to VFR by late afternoon. Local MVFR visibilities
in freezing fog over southwest Montana will end by mid-afternoon.
For tonight through Thursday morning expect scattered snow over the
Rocky Mountain Front. For tonight into early Thursday morning for
KCTB and KLWT some guidance suggests IFR ceilings and/or
visibilities in freezing fog could return but think there will be
enough wind to prevent this from happening so did not mention in
their TAFs. At KHVR IFR ceilings and/or visibilities in freezing fog
could also return but think there is a better chance there relative
to KLWT/KCTB so included in their taf. But some guidance keeps
conditions VFR at KHVR. For late tonight think southwest winds will
dissipate the freezing fog at KHVR but should southwest winds not
develop IFR conditions could linger into Thursday morning.

&&

.PREV DISCUSSION...
/ISSUED 807 AM MST Wed Dec 17 2014/
FXUS65 KTFX 171507
AFDTFX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREAT FALLS MT
807 AM MST Wed Dec 17 2014

UPDATE...
Dense freezing fog is no longer expected over Cascade and Judith
Basin Counties so the freezing fog advisory for those counties has
been canceled.

&&

.PREV DISCUSSION...
/ISSUED 510 AM MST Wed Dec 17 2014/

Tonight through Friday...Central Montana is underneath an area of
weak cyclonic flow aloft. Precipitation associated with a
disturbance in this flow will move east of the zones today. A weak
trof over over the Eastern Pacific will move over the Pacific
Northwest today and the zones will be underneath the southwest flow
ahead of this system. Flow aloft and dynamics will remain weak,
however. Models show very little warming of the airmass yet raise
temperatures from yesterday. With cloud cover and, possibly, areas
of fog, not convinced that all of that warming will occur and will
moderate high temps somewhat. The airmass will remain unsettled
Thursday as the trof over the Eastern Pacific slowly moves east and
and approaches the zones. Little chance of precipitation is expected
with this system. The Rockies and mountains of Southwest Montana
will have the best chance for snow although accumulations will
remain low. Zelzer

Friday Night through Wednesday...A weak shortwave trough will move
through Montana Friday night into Saturday, bringing just a chance
of snow to the mountains. Forecast models continue to indicate that
the pattern will then change for Saturday night through Tuesday. An
upper level high pressure ridge will strengthen off the California
coast and a low pressure trough will deepen from Hudson Bay into the
Great Lakes. This will result in Montana being under a strong
northwesterly flow aloft. The models indicate that the strongest
winds aloft will occur Sunday into Sunday night with the passage of
a disturbance embedded in the flow. However, the models differ on
just how strong these winds will be. The ECMWF only forecasts winds
of 45 to 55 kts at 700 mb, while the GFS generally has 60 to 70 kt
winds. Have therefore used a compromise solution between these two
models with regards to surface wind strength. Despite this
difference, this set-up will bring gusty westerly downslope winds to
much of the area, but especially over the plains of north central
Montana. In fact, some areas along the Rocky Mountain Front could
approach High Wind criteria (40 mph sustained/58 mph gusts).
Confidence remains moderate that High Wind highlights may be needed
for this event. The only concern is that the northwesterly wind
direction is not as favorable for widespread High Winds. There is
also significant moisture with this disturbance, so have continued
to spread the chance for precipitation out onto the plains. Winds
aloft will decrease somewhat after the passage of the disturbance,
but the northwesterly flow aloft will remain fairly moist, so have
kept the chance for precipitation above climatological normals
across the area into Tuesday. A potentially significant weather
system originating in the Gulf of Alaska is then forecast to move
into Montana Tuesday into Wednesday, bringing a very good chance of
precipitation. Because this feature is near the end of the period,
exact timing and types of precipitation are very uncertain.
Regardless, this system will need to be monitored for potential
winter weather highlights, especially considering that it would be
moving into the area during peak holiday travel time. The breezy
winds through Monday will keep temperatures around 10 degrees above
normal. The warmest day of the period appears to be Monday, when
most lower elevation locations should get well into the 40s.
However, with the system moving into the area at the end of the
period, temperatures will likely fall back to near or slightly below
seasonal averages by Wednesday.
Coulston

&&

.PRELIMINARY POINT TEMPS/POPS...
GTF  35  24  38  26 /  20  10  10  10
CTB  26  21  37  24 /  10  10  10  10
HLN  33  17  33  19 /  20  10  20  10
BZN  28  12  30  14 /  40  10  10  10
WEY  32  16  30  18 /  30  20  20  20
DLN  31  16  33  19 /  10  10  20  10
HVR  29  19  36  21 /  30  10  10  10
LWT  36  22  41  24 /  40  10  10  10

&&

.TFX WATCHES/WARNINGS/ADVISORIES...
FREEZING FOG ADVISORY until 11 AM MST this morning Eastern
Glacier...Toole.

&&

$$

weather.gov/greatfalls
www.twitter.com/NWSGreatFalls
www.facebook.com/NWSGreatFalls







000
FXUS65 KBYZ 171757
AFDBYZ

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BILLINGS MT
1057 AM MST WED DEC 17 2014

.UPDATE...
A QUICK UPDATE TO DROP THE DENSE FOG ADVISORY FOR THE CITY
OF SHERIDAN. FOG HAS BEGUN TO BREAKUP AND THIS TREND WILL
CONTINUE FOR THE REMAINDER OF THE MORNING. WILL GO AHEAD AND
CANCEL THE DENSE FOG ADVISORY. PATCHY DENSE FOG WILL CONTINUE
OVER THE AREA THROUGH TODAY BUT IS NOT EXPECTED TO BECOME
WIDESPREAD. RICHMOND

&&

.SHORT TERM...VALID FOR TDY AND THU...

SHERIDAN WAS REPORTING DENSE FOG THIS MORNING AND AREA WEB CAMS
IN SHERIDAN ALSO SHOWED DENSE FOG. LAST FEW RUNS OF THE HRRR
TARGETED THE SHERIDAN FOOTHILLS WITH DENSE FOG AND DISSIPATED IT
BY 19Z. HAVE ISSUED A DENSE FOG ADVISORY FOR THIS AREA THROUGH
18Z. OTHER AREAS E OF KBIL WILL ALSO HAVE FOG...AND SOME OF IT MAY
BE DENSE...BUT DENSE FOG WILL NOT BE WIDESPREAD ENOUGH TO WARRANT
AN ADVISORY.

TWO SHORTWAVES WERE AFFECTING THE AREA EARLY THIS MORNING. ONE WAS
MOVING INTO SW MT AND THE OTHER WAS OVER W MT PER WATER VAPOR
IMAGERY. THESE WAVES WILL MERGE AND CROSS THE AREA TODAY THROUGH
TONIGHT. THE BEST Q-VECTOR CONVERGENCE WILL OCCUR THIS MORNING
WITH THE WAVES...AND MODELS BROUGHT A DECENT AREA OF MOISTURE
ACROSS THE AREA. DETERMINISTIC MODELS AND SREF ALL SHOWED LIGHT
WIDELY SCATTERED QPF TODAY. SO WENT WITH MAINLY SCATTERED
FLURRIES...WITH CHANCE POPS IN THE WESTERN MOUNTAINS THIS MORNING.
CHANCES FOR PRECIPITATION WILL END TONIGHT. A WARM FRONT WILL PUSH
INTO THE REGION TONIGHT AND USHER IN WARMING CONDITIONS THROUGH
THU. ANOTHER WAVE APPROACHES THU AND MOVES INTO THE AREA THU
NIGHT. PRECIPITATION CHANCES WILL BE CONFINED TO THE MOUNTAINS.

TEMPERATURES TODAY WILL BE HIGHER THAN YESTERDAY/S READINGS AND
WILL BE WARMER YET ON THU. ARTHUR

.LONG TERM...VALID FOR FRI...SAT...SUN...MON...TUE...

MODELS ARE IN DECENT AGREEMENT THROUGH THE EXTENDED PERIOD AS
THEY SHOW AN UNSETTLED PATTERN. MAIN FORECAST ISSUE WILL BE SUNDAY
INTO MONDAY AND AGAIN CHRISTMAS EVE/CHRISTMAS DAY AS THESE
PERIODS SHOW THE LIKELIHOOD OF A STORM SYSTEM IMPACTING THE AREA.
BRIEF RIDGING WILL BE OVER THE FORECAST AREA FRIDAY BEFORE A WEAK
DISTURBANCE MOVES ACROSS THE AREA FRIDAY NIGHT INTO SATURDAY
BRINGING A SLIGHT CHANCE FOR RAIN AND SNOW SHOWERS. AN UNSETTLED
NORTHWEST FLOW ALOFT WILL PREVAIL OVER THE WEEKEND RESULTING IN A
SLIGHT SHOWER CHANCE SATURDAY. LEE-SIDE TROUGHING SETS UP SUNDAY
BEFORE A COLD FRONT MOVES THROUGH MONDAY. TIGHT PRESSURE GRADIENTS
WILL BE ACROSS THE BEARTOOTH/ABSAROKA FOOTHILLS SUNDAY SHIFTING
EAST MONDAY RESULTING IN WINDY PERIODS ACROSS THE AREA.

A CONTINUOUS FLOW OF MOISTURE OFF THE PACIFIC WILL MOVE ACROSS
IDAHO INTO MONTANA SUNDAY INTO MONDAY BRINGING CHANCES FOR SHOWERS
ACROSS THE PLAINS WITH SNOW LIKELY FOR THE MOUNTAINS. THERE WILL
BE A BRIEF BREAK TUESDAY BEFORE THE NEXT STORM SYSTEM IMPACTS OUR
FORECAST AREA WEDNESDAY AND THURSDAY. MODELS ARE IN PRETTY GOOD
AGREEMENT IN CARVING OUT A LARGE TROUGH ACROSS THE NORTHERN
ROCKIES WEDNESDAY AND THURSDAY...AS WELL AS PLACING AN UPPER LOW
IN OUR VICINITY. FORECASTER CONFIDENCE IS HIGH FOR A CHRISTMAS
SNOW EVENT BUT DETAILS SUCH AS SNOW AMOUNTS ARE UNCERTAIN AT THIS
TIME. HOOLEY
&&

.AVIATION...

LOW CEILINGS ALONG WITH AREAS OF DENSE FOG WILL CONTINUE TO POSE
AN AVIATION HAZARD THROUGH THIS MORNING. MVFR TO IFR CONDITIONS
WILL PREVAIL WITH AREAS OF LIFR FROM KSHR TO KBIL THROUGH 18Z. THE
EXCEPTION WILL BE THE KLVM AREA AND ADJACENT FOOTHILLS WHERE VFR
CONDITIONS WILL PREVAIL. THE MOUNTAINS WILL BE OBSCURED AT TIMES
THROUGHOUT THE DAY. HOOLEY/REIMER



&&

.PRELIMINARY POINT TEMP/POPS...

    TDY THU     FRI     SAT     SUN     MON     TUE
-------------------------------------------------------
BIL 033 023/039 023/038 027/042 026/044 035/047 027/041
    2/B 00/B    00/B    11/B    23/W    33/W    32/W
LVM 036 022/041 024/040 026/043 026/041 036/047 027/043
    3/B 01/N    11/B    21/N    23/W    33/W    33/W
HDN 031 015/037 016/037 020/040 019/041 029/044 023/040
    2/B 10/B    00/B    01/B    12/J    33/W    32/W
MLS 028 017/036 019/037 019/039 022/041 029/043 023/039
    2/J 10/B    00/B    11/B    12/J    23/W    11/B
4BQ 029 016/039 017/040 017/041 020/043 030/045 024/041
    2/E 10/B    00/B    11/B    12/J    23/W    21/B
BHK 022 015/034 018/037 017/039 020/040 027/041 021/037
    2/J 20/B    10/B    01/B    11/B    22/W    11/B
SHR 032 016/038 016/038 019/040 019/041 028/043 022/040
    2/B 00/B    10/B    12/J    12/J    34/W    32/W

&&

.BYZ WATCHES/WARNINGS/ADVISORIES...
MT...NONE.
WY...NONE.

&&

$$
WEATHER.GOV/BILLINGS



000
FXUS65 KBYZ 171757
AFDBYZ

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BILLINGS MT
1057 AM MST WED DEC 17 2014

.UPDATE...
A QUICK UPDATE TO DROP THE DENSE FOG ADVISORY FOR THE CITY
OF SHERIDAN. FOG HAS BEGUN TO BREAKUP AND THIS TREND WILL
CONTINUE FOR THE REMAINDER OF THE MORNING. WILL GO AHEAD AND
CANCEL THE DENSE FOG ADVISORY. PATCHY DENSE FOG WILL CONTINUE
OVER THE AREA THROUGH TODAY BUT IS NOT EXPECTED TO BECOME
WIDESPREAD. RICHMOND

&&

.SHORT TERM...VALID FOR TDY AND THU...

SHERIDAN WAS REPORTING DENSE FOG THIS MORNING AND AREA WEB CAMS
IN SHERIDAN ALSO SHOWED DENSE FOG. LAST FEW RUNS OF THE HRRR
TARGETED THE SHERIDAN FOOTHILLS WITH DENSE FOG AND DISSIPATED IT
BY 19Z. HAVE ISSUED A DENSE FOG ADVISORY FOR THIS AREA THROUGH
18Z. OTHER AREAS E OF KBIL WILL ALSO HAVE FOG...AND SOME OF IT MAY
BE DENSE...BUT DENSE FOG WILL NOT BE WIDESPREAD ENOUGH TO WARRANT
AN ADVISORY.

TWO SHORTWAVES WERE AFFECTING THE AREA EARLY THIS MORNING. ONE WAS
MOVING INTO SW MT AND THE OTHER WAS OVER W MT PER WATER VAPOR
IMAGERY. THESE WAVES WILL MERGE AND CROSS THE AREA TODAY THROUGH
TONIGHT. THE BEST Q-VECTOR CONVERGENCE WILL OCCUR THIS MORNING
WITH THE WAVES...AND MODELS BROUGHT A DECENT AREA OF MOISTURE
ACROSS THE AREA. DETERMINISTIC MODELS AND SREF ALL SHOWED LIGHT
WIDELY SCATTERED QPF TODAY. SO WENT WITH MAINLY SCATTERED
FLURRIES...WITH CHANCE POPS IN THE WESTERN MOUNTAINS THIS MORNING.
CHANCES FOR PRECIPITATION WILL END TONIGHT. A WARM FRONT WILL PUSH
INTO THE REGION TONIGHT AND USHER IN WARMING CONDITIONS THROUGH
THU. ANOTHER WAVE APPROACHES THU AND MOVES INTO THE AREA THU
NIGHT. PRECIPITATION CHANCES WILL BE CONFINED TO THE MOUNTAINS.

TEMPERATURES TODAY WILL BE HIGHER THAN YESTERDAY/S READINGS AND
WILL BE WARMER YET ON THU. ARTHUR

.LONG TERM...VALID FOR FRI...SAT...SUN...MON...TUE...

MODELS ARE IN DECENT AGREEMENT THROUGH THE EXTENDED PERIOD AS
THEY SHOW AN UNSETTLED PATTERN. MAIN FORECAST ISSUE WILL BE SUNDAY
INTO MONDAY AND AGAIN CHRISTMAS EVE/CHRISTMAS DAY AS THESE
PERIODS SHOW THE LIKELIHOOD OF A STORM SYSTEM IMPACTING THE AREA.
BRIEF RIDGING WILL BE OVER THE FORECAST AREA FRIDAY BEFORE A WEAK
DISTURBANCE MOVES ACROSS THE AREA FRIDAY NIGHT INTO SATURDAY
BRINGING A SLIGHT CHANCE FOR RAIN AND SNOW SHOWERS. AN UNSETTLED
NORTHWEST FLOW ALOFT WILL PREVAIL OVER THE WEEKEND RESULTING IN A
SLIGHT SHOWER CHANCE SATURDAY. LEE-SIDE TROUGHING SETS UP SUNDAY
BEFORE A COLD FRONT MOVES THROUGH MONDAY. TIGHT PRESSURE GRADIENTS
WILL BE ACROSS THE BEARTOOTH/ABSAROKA FOOTHILLS SUNDAY SHIFTING
EAST MONDAY RESULTING IN WINDY PERIODS ACROSS THE AREA.

A CONTINUOUS FLOW OF MOISTURE OFF THE PACIFIC WILL MOVE ACROSS
IDAHO INTO MONTANA SUNDAY INTO MONDAY BRINGING CHANCES FOR SHOWERS
ACROSS THE PLAINS WITH SNOW LIKELY FOR THE MOUNTAINS. THERE WILL
BE A BRIEF BREAK TUESDAY BEFORE THE NEXT STORM SYSTEM IMPACTS OUR
FORECAST AREA WEDNESDAY AND THURSDAY. MODELS ARE IN PRETTY GOOD
AGREEMENT IN CARVING OUT A LARGE TROUGH ACROSS THE NORTHERN
ROCKIES WEDNESDAY AND THURSDAY...AS WELL AS PLACING AN UPPER LOW
IN OUR VICINITY. FORECASTER CONFIDENCE IS HIGH FOR A CHRISTMAS
SNOW EVENT BUT DETAILS SUCH AS SNOW AMOUNTS ARE UNCERTAIN AT THIS
TIME. HOOLEY
&&

.AVIATION...

LOW CEILINGS ALONG WITH AREAS OF DENSE FOG WILL CONTINUE TO POSE
AN AVIATION HAZARD THROUGH THIS MORNING. MVFR TO IFR CONDITIONS
WILL PREVAIL WITH AREAS OF LIFR FROM KSHR TO KBIL THROUGH 18Z. THE
EXCEPTION WILL BE THE KLVM AREA AND ADJACENT FOOTHILLS WHERE VFR
CONDITIONS WILL PREVAIL. THE MOUNTAINS WILL BE OBSCURED AT TIMES
THROUGHOUT THE DAY. HOOLEY/REIMER



&&

.PRELIMINARY POINT TEMP/POPS...

    TDY THU     FRI     SAT     SUN     MON     TUE
-------------------------------------------------------
BIL 033 023/039 023/038 027/042 026/044 035/047 027/041
    2/B 00/B    00/B    11/B    23/W    33/W    32/W
LVM 036 022/041 024/040 026/043 026/041 036/047 027/043
    3/B 01/N    11/B    21/N    23/W    33/W    33/W
HDN 031 015/037 016/037 020/040 019/041 029/044 023/040
    2/B 10/B    00/B    01/B    12/J    33/W    32/W
MLS 028 017/036 019/037 019/039 022/041 029/043 023/039
    2/J 10/B    00/B    11/B    12/J    23/W    11/B
4BQ 029 016/039 017/040 017/041 020/043 030/045 024/041
    2/E 10/B    00/B    11/B    12/J    23/W    21/B
BHK 022 015/034 018/037 017/039 020/040 027/041 021/037
    2/J 20/B    10/B    01/B    11/B    22/W    11/B
SHR 032 016/038 016/038 019/040 019/041 028/043 022/040
    2/B 00/B    10/B    12/J    12/J    34/W    32/W

&&

.BYZ WATCHES/WARNINGS/ADVISORIES...
MT...NONE.
WY...NONE.

&&

$$
WEATHER.GOV/BILLINGS



000
FXUS65 KBYZ 171757
AFDBYZ

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BILLINGS MT
1057 AM MST WED DEC 17 2014

.UPDATE...
A QUICK UPDATE TO DROP THE DENSE FOG ADVISORY FOR THE CITY
OF SHERIDAN. FOG HAS BEGUN TO BREAKUP AND THIS TREND WILL
CONTINUE FOR THE REMAINDER OF THE MORNING. WILL GO AHEAD AND
CANCEL THE DENSE FOG ADVISORY. PATCHY DENSE FOG WILL CONTINUE
OVER THE AREA THROUGH TODAY BUT IS NOT EXPECTED TO BECOME
WIDESPREAD. RICHMOND

&&

.SHORT TERM...VALID FOR TDY AND THU...

SHERIDAN WAS REPORTING DENSE FOG THIS MORNING AND AREA WEB CAMS
IN SHERIDAN ALSO SHOWED DENSE FOG. LAST FEW RUNS OF THE HRRR
TARGETED THE SHERIDAN FOOTHILLS WITH DENSE FOG AND DISSIPATED IT
BY 19Z. HAVE ISSUED A DENSE FOG ADVISORY FOR THIS AREA THROUGH
18Z. OTHER AREAS E OF KBIL WILL ALSO HAVE FOG...AND SOME OF IT MAY
BE DENSE...BUT DENSE FOG WILL NOT BE WIDESPREAD ENOUGH TO WARRANT
AN ADVISORY.

TWO SHORTWAVES WERE AFFECTING THE AREA EARLY THIS MORNING. ONE WAS
MOVING INTO SW MT AND THE OTHER WAS OVER W MT PER WATER VAPOR
IMAGERY. THESE WAVES WILL MERGE AND CROSS THE AREA TODAY THROUGH
TONIGHT. THE BEST Q-VECTOR CONVERGENCE WILL OCCUR THIS MORNING
WITH THE WAVES...AND MODELS BROUGHT A DECENT AREA OF MOISTURE
ACROSS THE AREA. DETERMINISTIC MODELS AND SREF ALL SHOWED LIGHT
WIDELY SCATTERED QPF TODAY. SO WENT WITH MAINLY SCATTERED
FLURRIES...WITH CHANCE POPS IN THE WESTERN MOUNTAINS THIS MORNING.
CHANCES FOR PRECIPITATION WILL END TONIGHT. A WARM FRONT WILL PUSH
INTO THE REGION TONIGHT AND USHER IN WARMING CONDITIONS THROUGH
THU. ANOTHER WAVE APPROACHES THU AND MOVES INTO THE AREA THU
NIGHT. PRECIPITATION CHANCES WILL BE CONFINED TO THE MOUNTAINS.

TEMPERATURES TODAY WILL BE HIGHER THAN YESTERDAY/S READINGS AND
WILL BE WARMER YET ON THU. ARTHUR

.LONG TERM...VALID FOR FRI...SAT...SUN...MON...TUE...

MODELS ARE IN DECENT AGREEMENT THROUGH THE EXTENDED PERIOD AS
THEY SHOW AN UNSETTLED PATTERN. MAIN FORECAST ISSUE WILL BE SUNDAY
INTO MONDAY AND AGAIN CHRISTMAS EVE/CHRISTMAS DAY AS THESE
PERIODS SHOW THE LIKELIHOOD OF A STORM SYSTEM IMPACTING THE AREA.
BRIEF RIDGING WILL BE OVER THE FORECAST AREA FRIDAY BEFORE A WEAK
DISTURBANCE MOVES ACROSS THE AREA FRIDAY NIGHT INTO SATURDAY
BRINGING A SLIGHT CHANCE FOR RAIN AND SNOW SHOWERS. AN UNSETTLED
NORTHWEST FLOW ALOFT WILL PREVAIL OVER THE WEEKEND RESULTING IN A
SLIGHT SHOWER CHANCE SATURDAY. LEE-SIDE TROUGHING SETS UP SUNDAY
BEFORE A COLD FRONT MOVES THROUGH MONDAY. TIGHT PRESSURE GRADIENTS
WILL BE ACROSS THE BEARTOOTH/ABSAROKA FOOTHILLS SUNDAY SHIFTING
EAST MONDAY RESULTING IN WINDY PERIODS ACROSS THE AREA.

A CONTINUOUS FLOW OF MOISTURE OFF THE PACIFIC WILL MOVE ACROSS
IDAHO INTO MONTANA SUNDAY INTO MONDAY BRINGING CHANCES FOR SHOWERS
ACROSS THE PLAINS WITH SNOW LIKELY FOR THE MOUNTAINS. THERE WILL
BE A BRIEF BREAK TUESDAY BEFORE THE NEXT STORM SYSTEM IMPACTS OUR
FORECAST AREA WEDNESDAY AND THURSDAY. MODELS ARE IN PRETTY GOOD
AGREEMENT IN CARVING OUT A LARGE TROUGH ACROSS THE NORTHERN
ROCKIES WEDNESDAY AND THURSDAY...AS WELL AS PLACING AN UPPER LOW
IN OUR VICINITY. FORECASTER CONFIDENCE IS HIGH FOR A CHRISTMAS
SNOW EVENT BUT DETAILS SUCH AS SNOW AMOUNTS ARE UNCERTAIN AT THIS
TIME. HOOLEY
&&

.AVIATION...

LOW CEILINGS ALONG WITH AREAS OF DENSE FOG WILL CONTINUE TO POSE
AN AVIATION HAZARD THROUGH THIS MORNING. MVFR TO IFR CONDITIONS
WILL PREVAIL WITH AREAS OF LIFR FROM KSHR TO KBIL THROUGH 18Z. THE
EXCEPTION WILL BE THE KLVM AREA AND ADJACENT FOOTHILLS WHERE VFR
CONDITIONS WILL PREVAIL. THE MOUNTAINS WILL BE OBSCURED AT TIMES
THROUGHOUT THE DAY. HOOLEY/REIMER



&&

.PRELIMINARY POINT TEMP/POPS...

    TDY THU     FRI     SAT     SUN     MON     TUE
-------------------------------------------------------
BIL 033 023/039 023/038 027/042 026/044 035/047 027/041
    2/B 00/B    00/B    11/B    23/W    33/W    32/W
LVM 036 022/041 024/040 026/043 026/041 036/047 027/043
    3/B 01/N    11/B    21/N    23/W    33/W    33/W
HDN 031 015/037 016/037 020/040 019/041 029/044 023/040
    2/B 10/B    00/B    01/B    12/J    33/W    32/W
MLS 028 017/036 019/037 019/039 022/041 029/043 023/039
    2/J 10/B    00/B    11/B    12/J    23/W    11/B
4BQ 029 016/039 017/040 017/041 020/043 030/045 024/041
    2/E 10/B    00/B    11/B    12/J    23/W    21/B
BHK 022 015/034 018/037 017/039 020/040 027/041 021/037
    2/J 20/B    10/B    01/B    11/B    22/W    11/B
SHR 032 016/038 016/038 019/040 019/041 028/043 022/040
    2/B 00/B    10/B    12/J    12/J    34/W    32/W

&&

.BYZ WATCHES/WARNINGS/ADVISORIES...
MT...NONE.
WY...NONE.

&&

$$
WEATHER.GOV/BILLINGS



000
FXUS65 KBYZ 171757
AFDBYZ

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BILLINGS MT
1057 AM MST WED DEC 17 2014

.UPDATE...
A QUICK UPDATE TO DROP THE DENSE FOG ADVISORY FOR THE CITY
OF SHERIDAN. FOG HAS BEGUN TO BREAKUP AND THIS TREND WILL
CONTINUE FOR THE REMAINDER OF THE MORNING. WILL GO AHEAD AND
CANCEL THE DENSE FOG ADVISORY. PATCHY DENSE FOG WILL CONTINUE
OVER THE AREA THROUGH TODAY BUT IS NOT EXPECTED TO BECOME
WIDESPREAD. RICHMOND

&&

.SHORT TERM...VALID FOR TDY AND THU...

SHERIDAN WAS REPORTING DENSE FOG THIS MORNING AND AREA WEB CAMS
IN SHERIDAN ALSO SHOWED DENSE FOG. LAST FEW RUNS OF THE HRRR
TARGETED THE SHERIDAN FOOTHILLS WITH DENSE FOG AND DISSIPATED IT
BY 19Z. HAVE ISSUED A DENSE FOG ADVISORY FOR THIS AREA THROUGH
18Z. OTHER AREAS E OF KBIL WILL ALSO HAVE FOG...AND SOME OF IT MAY
BE DENSE...BUT DENSE FOG WILL NOT BE WIDESPREAD ENOUGH TO WARRANT
AN ADVISORY.

TWO SHORTWAVES WERE AFFECTING THE AREA EARLY THIS MORNING. ONE WAS
MOVING INTO SW MT AND THE OTHER WAS OVER W MT PER WATER VAPOR
IMAGERY. THESE WAVES WILL MERGE AND CROSS THE AREA TODAY THROUGH
TONIGHT. THE BEST Q-VECTOR CONVERGENCE WILL OCCUR THIS MORNING
WITH THE WAVES...AND MODELS BROUGHT A DECENT AREA OF MOISTURE
ACROSS THE AREA. DETERMINISTIC MODELS AND SREF ALL SHOWED LIGHT
WIDELY SCATTERED QPF TODAY. SO WENT WITH MAINLY SCATTERED
FLURRIES...WITH CHANCE POPS IN THE WESTERN MOUNTAINS THIS MORNING.
CHANCES FOR PRECIPITATION WILL END TONIGHT. A WARM FRONT WILL PUSH
INTO THE REGION TONIGHT AND USHER IN WARMING CONDITIONS THROUGH
THU. ANOTHER WAVE APPROACHES THU AND MOVES INTO THE AREA THU
NIGHT. PRECIPITATION CHANCES WILL BE CONFINED TO THE MOUNTAINS.

TEMPERATURES TODAY WILL BE HIGHER THAN YESTERDAY/S READINGS AND
WILL BE WARMER YET ON THU. ARTHUR

.LONG TERM...VALID FOR FRI...SAT...SUN...MON...TUE...

MODELS ARE IN DECENT AGREEMENT THROUGH THE EXTENDED PERIOD AS
THEY SHOW AN UNSETTLED PATTERN. MAIN FORECAST ISSUE WILL BE SUNDAY
INTO MONDAY AND AGAIN CHRISTMAS EVE/CHRISTMAS DAY AS THESE
PERIODS SHOW THE LIKELIHOOD OF A STORM SYSTEM IMPACTING THE AREA.
BRIEF RIDGING WILL BE OVER THE FORECAST AREA FRIDAY BEFORE A WEAK
DISTURBANCE MOVES ACROSS THE AREA FRIDAY NIGHT INTO SATURDAY
BRINGING A SLIGHT CHANCE FOR RAIN AND SNOW SHOWERS. AN UNSETTLED
NORTHWEST FLOW ALOFT WILL PREVAIL OVER THE WEEKEND RESULTING IN A
SLIGHT SHOWER CHANCE SATURDAY. LEE-SIDE TROUGHING SETS UP SUNDAY
BEFORE A COLD FRONT MOVES THROUGH MONDAY. TIGHT PRESSURE GRADIENTS
WILL BE ACROSS THE BEARTOOTH/ABSAROKA FOOTHILLS SUNDAY SHIFTING
EAST MONDAY RESULTING IN WINDY PERIODS ACROSS THE AREA.

A CONTINUOUS FLOW OF MOISTURE OFF THE PACIFIC WILL MOVE ACROSS
IDAHO INTO MONTANA SUNDAY INTO MONDAY BRINGING CHANCES FOR SHOWERS
ACROSS THE PLAINS WITH SNOW LIKELY FOR THE MOUNTAINS. THERE WILL
BE A BRIEF BREAK TUESDAY BEFORE THE NEXT STORM SYSTEM IMPACTS OUR
FORECAST AREA WEDNESDAY AND THURSDAY. MODELS ARE IN PRETTY GOOD
AGREEMENT IN CARVING OUT A LARGE TROUGH ACROSS THE NORTHERN
ROCKIES WEDNESDAY AND THURSDAY...AS WELL AS PLACING AN UPPER LOW
IN OUR VICINITY. FORECASTER CONFIDENCE IS HIGH FOR A CHRISTMAS
SNOW EVENT BUT DETAILS SUCH AS SNOW AMOUNTS ARE UNCERTAIN AT THIS
TIME. HOOLEY
&&

.AVIATION...

LOW CEILINGS ALONG WITH AREAS OF DENSE FOG WILL CONTINUE TO POSE
AN AVIATION HAZARD THROUGH THIS MORNING. MVFR TO IFR CONDITIONS
WILL PREVAIL WITH AREAS OF LIFR FROM KSHR TO KBIL THROUGH 18Z. THE
EXCEPTION WILL BE THE KLVM AREA AND ADJACENT FOOTHILLS WHERE VFR
CONDITIONS WILL PREVAIL. THE MOUNTAINS WILL BE OBSCURED AT TIMES
THROUGHOUT THE DAY. HOOLEY/REIMER



&&

.PRELIMINARY POINT TEMP/POPS...

    TDY THU     FRI     SAT     SUN     MON     TUE
-------------------------------------------------------
BIL 033 023/039 023/038 027/042 026/044 035/047 027/041
    2/B 00/B    00/B    11/B    23/W    33/W    32/W
LVM 036 022/041 024/040 026/043 026/041 036/047 027/043
    3/B 01/N    11/B    21/N    23/W    33/W    33/W
HDN 031 015/037 016/037 020/040 019/041 029/044 023/040
    2/B 10/B    00/B    01/B    12/J    33/W    32/W
MLS 028 017/036 019/037 019/039 022/041 029/043 023/039
    2/J 10/B    00/B    11/B    12/J    23/W    11/B
4BQ 029 016/039 017/040 017/041 020/043 030/045 024/041
    2/E 10/B    00/B    11/B    12/J    23/W    21/B
BHK 022 015/034 018/037 017/039 020/040 027/041 021/037
    2/J 20/B    10/B    01/B    11/B    22/W    11/B
SHR 032 016/038 016/038 019/040 019/041 028/043 022/040
    2/B 00/B    10/B    12/J    12/J    34/W    32/W

&&

.BYZ WATCHES/WARNINGS/ADVISORIES...
MT...NONE.
WY...NONE.

&&

$$
WEATHER.GOV/BILLINGS



000
FXUS65 KTFX 171654
AFDTFX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREAT FALLS MT
954 AM MST Wed Dec 17 2014

.UPDATE...
Have continued to decrease the area of the freezing fog advisory.
Have also lowered high temperatures where the freezing fog is
persisting and already keeping locations cooler than previous
forecast. Otherwise no significant changes to the forecast this
morning. Suk


&&

.AVIATION...
UPDATED 1209Z.
Light snow has ended across most of Central Montana although
northeastern portions, near and east of KHVR and KLWT, continue to
see light snow. Winds will remain light today and areas of fog, and
some dense freezing fog along northern portions of the region, will
continue into the morning. Widespread IFR conditions will continue
into late morning near KCTB.

&&

.PREV DISCUSSION...
/ISSUED 807 AM MST Wed Dec 17 2014/
FXUS65 KTFX 171507
AFDTFX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREAT FALLS MT
807 AM MST Wed Dec 17 2014

UPDATE...
Dense freezing fog is no longer expected over Cascade and Judith
Basin Counties so the freezing fog advisory for those counties has
been canceled.

&&

.PRELIMINARY POINT TEMPS/POPS...
GTF  35  24  38  26 /  20  10  10  10
CTB  26  21  37  24 /  10  10  10  10
HLN  33  17  33  19 /  20  10  20  10
BZN  28  12  30  14 /  40  10  10  10
WEY  32  16  30  18 /  30  20  20  20
DLN  31  16  33  19 /  10  10  20  10
HVR  29  19  36  21 /  30  10  10  10
LWT  36  22  41  24 /  40  10  10  10

&&

.TFX WATCHES/WARNINGS/ADVISORIES...
FREEZING FOG ADVISORY until 11 AM MST this morning Eastern
Glacier...Toole.

&&

$$

weather.gov/greatfalls
www.twitter.com/NWSGreatFalls
www.facebook.com/NWSGreatFalls






000
FXUS65 KTFX 171654
AFDTFX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREAT FALLS MT
954 AM MST Wed Dec 17 2014

.UPDATE...
Have continued to decrease the area of the freezing fog advisory.
Have also lowered high temperatures where the freezing fog is
persisting and already keeping locations cooler than previous
forecast. Otherwise no significant changes to the forecast this
morning. Suk


&&

.AVIATION...
UPDATED 1209Z.
Light snow has ended across most of Central Montana although
northeastern portions, near and east of KHVR and KLWT, continue to
see light snow. Winds will remain light today and areas of fog, and
some dense freezing fog along northern portions of the region, will
continue into the morning. Widespread IFR conditions will continue
into late morning near KCTB.

&&

.PREV DISCUSSION...
/ISSUED 807 AM MST Wed Dec 17 2014/
FXUS65 KTFX 171507
AFDTFX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREAT FALLS MT
807 AM MST Wed Dec 17 2014

UPDATE...
Dense freezing fog is no longer expected over Cascade and Judith
Basin Counties so the freezing fog advisory for those counties has
been canceled.

&&

.PRELIMINARY POINT TEMPS/POPS...
GTF  35  24  38  26 /  20  10  10  10
CTB  26  21  37  24 /  10  10  10  10
HLN  33  17  33  19 /  20  10  20  10
BZN  28  12  30  14 /  40  10  10  10
WEY  32  16  30  18 /  30  20  20  20
DLN  31  16  33  19 /  10  10  20  10
HVR  29  19  36  21 /  30  10  10  10
LWT  36  22  41  24 /  40  10  10  10

&&

.TFX WATCHES/WARNINGS/ADVISORIES...
FREEZING FOG ADVISORY until 11 AM MST this morning Eastern
Glacier...Toole.

&&

$$

weather.gov/greatfalls
www.twitter.com/NWSGreatFalls
www.facebook.com/NWSGreatFalls





000
FXUS65 KGGW 171628
AFDGGW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GLASGOW MT
928 AM MST WED DEC 17 2014

.SHORT TERM...FOR NORTHEAST MONTANA...TODAY THROUGH FRIDAY...
UPDATE...

WITH PATCHY DENSE FOG BEING REPORTED IN OPHEIM...WILL HAVE A DENSE
FOG ADVISORY FOR NORTHERN VALLEY COUNTY AS WELL AS DANIELS.
OTHERWISE EXPECT PATCHY FOG AND LOW STRATUS TO CONTINUE THROUGH
THE DAY. WILL ALSO HAVE SNOW SHOWERS SPREADING NORTHEAST THROUGH
THE CWA...WHICH COULD MIX WITH FREEZING RAIN AT TIMES. DO NOT
EXPECT MUCH ACCUMULATIONS OF SNOW OR ICE AT THIS TIME. POPS/WX
GRIDS NOW REFLECT NEAR TERM TRENDS AND EXPECTATIONS. MALIAWCO

PREVIOUS DISCUSSION...
LOW STRATUS DECK REMAINS IN PLACE ACROSS EASTERN MONTANA. CEILINGS
ARE LOWERING...INCREASING THE POTENTIAL FOR FOG OVER THE HIGHER
TERRAIN AREAS. SHORTWAVE LIFTING OUT OF IDAHO EXPECTED TO BRING
INCREASED MOISTURE INTO THE MIDLEVEL...ALLOWING FOR A LITTLE MORE
MIXING AND INSTABILITY ALOFT. THIS COULD HELP CLEAR OUT THE LOWER
CLOUDS AND COULD PRODUCE A LITTLE LIGHT PRECIPITATION. MOSTLY
EXPECT PRECIP TO OCCUR AS SNOW BUT COULD SEE A LITTLE FREEZING
RAIN AS THE MOISTURE DEEPENS.

WINDS GO AROUND TO WEST BEHIND THE SHORTWAVE ON THURSDAY WHICH
SHOULD ALSO AID IN PUSHING THE LOW CLOUD OUT OF THE REGION.
AIRMASS ALOFT WARMS SOME BUT LOW LEVEL INVERSION SHOULD PERSIST
ESPECIALLY OVER THE RIVER VALLEYS OF NORTHEAST MONTANA. BY FRIDAY
UPPER RIDGE BUILDS INTO THE NORTHERN ROCKIES STARTING A CHINOOK
ALONG THE FRONT RANGE. EBERT


.LONG TERM...FRIDAY NIGHT THROUGH WEDNESDAY...

THE GENERAL SYNOPTIC FLOW REGIME FOR THE EXTENDED FORECAST PERIOD
WILL BE FROM THE WEST AND NORTHWEST WITH A FEW EMBEDDED SMALL-
SCALE DISTURBANCES EARLY IN THE PERIOD...FOLLOWED BY A LARGER-
SCALE STORM SYSTEM OVER THE REGION TOWARD CHRISTMAS EVE.

FIRST...EARLY SUNDAY MORNING...A SMALL DISTURBANCE EMERGES OVER
THE CANADIAN ROCKIES AND GAINS ENOUGH FORCING AND MOISTURE TO
SQUEEZE OUT SOME LIGHT PRECIPITATION. BASICALLY WENT WITH A MODEL
BLEND HERE...SLIGHTLY FAVORING THE EC FOR ITS RUN TO RUN
CONSISTENCY. NOT EXPECTING MUCH...MAYBE A HALF INCH OF SNOW NORTH
OF THE MISSOURI RIVER AND SOME LIGHT RAIN SOUTH OF THE MISSOURI
RIVER.

MONDAY NIGHT THROUGH WEDNESDAY NIGHT...A STRONGER AND MORE-
ESTABLISHED NORTHWESTERLY FLOW ALOFT SEEMS TO TAKE ROOT OVER THE
REGION AND SETS UP SOME HIGHER ELEVATION AREAS OF CENTRAL MONTANA
WITH OVER-RUNNING AND ACCUMULATING PRECIPITATION. THIS WILL LIKELY
REMAIN CONFINED TO THE NE AND SW CORNERS OF OUR CWA. MODELS
INDICATE THAT THIS PRECIPITATION TREND WILL LATER THE BECOME
ENHANCED BY A COLD AIR MASS...LARGER TROUGH...AND STRONGER STORM
SYSTEM POSSIBLY BY CHRISTMAS TIME. TRIED TO REFLECT THIS THINKING
WITH THE FORECAST GRIDS. BMICKELSON


&&

.AVIATION...
FLIGHT CONDITIONS: IFR THIS MORNING MAY RISE TO MVFR THIS
AFTERNOON BUT CONFIDENCE IS LOW. LOW CEILINGS WILL PLAGUE THE AREA
INTO THURSDAY MORNING. CLOUDS MAY THIN ENOUGH THURSDAY AFTERNOON.

PATCHY DENSE FREEZING FOG HAS BEEN REPORTED IN SOME OF THE HIGHER
ELEVATIONS.

WINDS: EAST-SOUTHEASTERLY WINDS WILL PERSIST AROUND 8 TO 12 KTS. TFJ


&&

.GLASGOW WATCHES/WARNINGS/ADVISORIES...
DENSE FOG ADVISORY UNTIL NOON MST TODAY FOR DANIELS...NORTHERN
VALLEY.

&&

$$

WEATHER.GOV/GLASGOW






000
FXUS65 KGGW 171628
AFDGGW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GLASGOW MT
928 AM MST WED DEC 17 2014

.SHORT TERM...FOR NORTHEAST MONTANA...TODAY THROUGH FRIDAY...
UPDATE...

WITH PATCHY DENSE FOG BEING REPORTED IN OPHEIM...WILL HAVE A DENSE
FOG ADVISORY FOR NORTHERN VALLEY COUNTY AS WELL AS DANIELS.
OTHERWISE EXPECT PATCHY FOG AND LOW STRATUS TO CONTINUE THROUGH
THE DAY. WILL ALSO HAVE SNOW SHOWERS SPREADING NORTHEAST THROUGH
THE CWA...WHICH COULD MIX WITH FREEZING RAIN AT TIMES. DO NOT
EXPECT MUCH ACCUMULATIONS OF SNOW OR ICE AT THIS TIME. POPS/WX
GRIDS NOW REFLECT NEAR TERM TRENDS AND EXPECTATIONS. MALIAWCO

PREVIOUS DISCUSSION...
LOW STRATUS DECK REMAINS IN PLACE ACROSS EASTERN MONTANA. CEILINGS
ARE LOWERING...INCREASING THE POTENTIAL FOR FOG OVER THE HIGHER
TERRAIN AREAS. SHORTWAVE LIFTING OUT OF IDAHO EXPECTED TO BRING
INCREASED MOISTURE INTO THE MIDLEVEL...ALLOWING FOR A LITTLE MORE
MIXING AND INSTABILITY ALOFT. THIS COULD HELP CLEAR OUT THE LOWER
CLOUDS AND COULD PRODUCE A LITTLE LIGHT PRECIPITATION. MOSTLY
EXPECT PRECIP TO OCCUR AS SNOW BUT COULD SEE A LITTLE FREEZING
RAIN AS THE MOISTURE DEEPENS.

WINDS GO AROUND TO WEST BEHIND THE SHORTWAVE ON THURSDAY WHICH
SHOULD ALSO AID IN PUSHING THE LOW CLOUD OUT OF THE REGION.
AIRMASS ALOFT WARMS SOME BUT LOW LEVEL INVERSION SHOULD PERSIST
ESPECIALLY OVER THE RIVER VALLEYS OF NORTHEAST MONTANA. BY FRIDAY
UPPER RIDGE BUILDS INTO THE NORTHERN ROCKIES STARTING A CHINOOK
ALONG THE FRONT RANGE. EBERT


.LONG TERM...FRIDAY NIGHT THROUGH WEDNESDAY...

THE GENERAL SYNOPTIC FLOW REGIME FOR THE EXTENDED FORECAST PERIOD
WILL BE FROM THE WEST AND NORTHWEST WITH A FEW EMBEDDED SMALL-
SCALE DISTURBANCES EARLY IN THE PERIOD...FOLLOWED BY A LARGER-
SCALE STORM SYSTEM OVER THE REGION TOWARD CHRISTMAS EVE.

FIRST...EARLY SUNDAY MORNING...A SMALL DISTURBANCE EMERGES OVER
THE CANADIAN ROCKIES AND GAINS ENOUGH FORCING AND MOISTURE TO
SQUEEZE OUT SOME LIGHT PRECIPITATION. BASICALLY WENT WITH A MODEL
BLEND HERE...SLIGHTLY FAVORING THE EC FOR ITS RUN TO RUN
CONSISTENCY. NOT EXPECTING MUCH...MAYBE A HALF INCH OF SNOW NORTH
OF THE MISSOURI RIVER AND SOME LIGHT RAIN SOUTH OF THE MISSOURI
RIVER.

MONDAY NIGHT THROUGH WEDNESDAY NIGHT...A STRONGER AND MORE-
ESTABLISHED NORTHWESTERLY FLOW ALOFT SEEMS TO TAKE ROOT OVER THE
REGION AND SETS UP SOME HIGHER ELEVATION AREAS OF CENTRAL MONTANA
WITH OVER-RUNNING AND ACCUMULATING PRECIPITATION. THIS WILL LIKELY
REMAIN CONFINED TO THE NE AND SW CORNERS OF OUR CWA. MODELS
INDICATE THAT THIS PRECIPITATION TREND WILL LATER THE BECOME
ENHANCED BY A COLD AIR MASS...LARGER TROUGH...AND STRONGER STORM
SYSTEM POSSIBLY BY CHRISTMAS TIME. TRIED TO REFLECT THIS THINKING
WITH THE FORECAST GRIDS. BMICKELSON


&&

.AVIATION...
FLIGHT CONDITIONS: IFR THIS MORNING MAY RISE TO MVFR THIS
AFTERNOON BUT CONFIDENCE IS LOW. LOW CEILINGS WILL PLAGUE THE AREA
INTO THURSDAY MORNING. CLOUDS MAY THIN ENOUGH THURSDAY AFTERNOON.

PATCHY DENSE FREEZING FOG HAS BEEN REPORTED IN SOME OF THE HIGHER
ELEVATIONS.

WINDS: EAST-SOUTHEASTERLY WINDS WILL PERSIST AROUND 8 TO 12 KTS. TFJ


&&

.GLASGOW WATCHES/WARNINGS/ADVISORIES...
DENSE FOG ADVISORY UNTIL NOON MST TODAY FOR DANIELS...NORTHERN
VALLEY.

&&

$$

WEATHER.GOV/GLASGOW





000
FXUS65 KBYZ 171621
AFDBYZ

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BILLINGS MT
921 AM MST WED DEC 17 2014

.UPDATE...
AREAS OF FOG STILL ON GOING ACROSS THE REGION THIS MORNING AND
WILL CONTINUE THROUGH AT LEAST 19Z FOR MANY AREAS FROM BILLINGS
EAST. DENSE FOG WAS CONTINUING IN THE SHERIDAN AND WILL KEEP THE
DENSE FOG ADVISORY GOING THROUGH AT LEAST 18Z. WEB CAMS AND
SURFACE OBSERVATIONS ALSO INDICATED PATCHY DENSE FOG WAS LOCATED
ACROSS THE SOUTHERN AREAS OF POWDER RIVER AND CARTER COUNTIES.
PATCHY FOG ALSO EXTENDED NORTHWARD FROM THESE AREAS AND HAD PUSHED
WESTWARD INTO THE BILLINGS AREA. HRRR INDICATING FOG IN THESE
AREAS WILL BEGIN BREAKING UP BY MID MORNING AS A WARM FRONT MOVES
ACROSS THE AREA ALLOWING SOME MIXING TO TAKE PLACE.

INCREASE POPS ACROSS THE AREA THIS MORNING AS A WEAK UPPER LEVEL
CIRCULATION ALONG WITH WEAK VORTICITY WAS PRODUCING LIGHT SNOW
SHOWERS OVER THE FORECAST AREA. NO SNOW ACCUMULATIONS ARE EXPECTED
WITH THIS DISTURBANCE. DID LOWER TEMPERATURES A FEW DEGREES AS
CLOUD COVER WILL INHIBIT HEATING THIS AFTERNOON IN SPITE OF WARM
FRONT MOVING THROUGH. RICHMOND

&&

.SHORT TERM...VALID FOR TDY AND THU...

SHERIDAN WAS REPORTING DENSE FOG THIS MORNING AND AREA WEB CAMS
IN SHERIDAN ALSO SHOWED DENSE FOG. LAST FEW RUNS OF THE HRRR
TARGETED THE SHERIDAN FOOTHILLS WITH DENSE FOG AND DISSIPATED IT
BY 19Z. HAVE ISSUED A DENSE FOG ADVISORY FOR THIS AREA THROUGH
18Z. OTHER AREAS E OF KBIL WILL ALSO HAVE FOG...AND SOME OF IT MAY
BE DENSE...BUT DENSE FOG WILL NOT BE WIDESPREAD ENOUGH TO WARRANT
AN ADVISORY.

TWO SHORTWAVES WERE AFFECTING THE AREA EARLY THIS MORNING. ONE WAS
MOVING INTO SW MT AND THE OTHER WAS OVER W MT PER WATER VAPOR
IMAGERY. THESE WAVES WILL MERGE AND CROSS THE AREA TODAY THROUGH
TONIGHT. THE BEST Q-VECTOR CONVERGENCE WILL OCCUR THIS MORNING
WITH THE WAVES...AND MODELS BROUGHT A DECENT AREA OF MOISTURE
ACROSS THE AREA. DETERMINISTIC MODELS AND SREF ALL SHOWED LIGHT
WIDELY SCATTERED QPF TODAY. SO WENT WITH MAINLY SCATTERED
FLURRIES...WITH CHANCE POPS IN THE WESTERN MOUNTAINS THIS MORNING.
CHANCES FOR PRECIPITATION WILL END TONIGHT. A WARM FRONT WILL PUSH
INTO THE REGION TONIGHT AND USHER IN WARMING CONDITIONS THROUGH
THU. ANOTHER WAVE APPROACHES THU AND MOVES INTO THE AREA THU
NIGHT. PRECIPITATION CHANCES WILL BE CONFINED TO THE MOUNTAINS.

TEMPERATURES TODAY WILL BE HIGHER THAN YESTERDAY/S READINGS AND
WILL BE WARMER YET ON THU. ARTHUR

.LONG TERM...VALID FOR FRI...SAT...SUN...MON...TUE...

MODELS ARE IN DECENT AGREEMENT THROUGH THE EXTENDED PERIOD AS
THEY SHOW AN UNSETTLED PATTERN. MAIN FORECAST ISSUE WILL BE SUNDAY
INTO MONDAY AND AGAIN CHRISTMAS EVE/CHRISTMAS DAY AS THESE
PERIODS SHOW THE LIKELIHOOD OF A STORM SYSTEM IMPACTING THE AREA.
BRIEF RIDGING WILL BE OVER THE FORECAST AREA FRIDAY BEFORE A WEAK
DISTURBANCE MOVES ACROSS THE AREA FRIDAY NIGHT INTO SATURDAY
BRINGING A SLIGHT CHANCE FOR RAIN AND SNOW SHOWERS. AN UNSETTLED
NORTHWEST FLOW ALOFT WILL PREVAIL OVER THE WEEKEND RESULTING IN A
SLIGHT SHOWER CHANCE SATURDAY. LEE-SIDE TROUGHING SETS UP SUNDAY
BEFORE A COLD FRONT MOVES THROUGH MONDAY. TIGHT PRESSURE GRADIENTS
WILL BE ACROSS THE BEARTOOTH/ABSAROKA FOOTHILLS SUNDAY SHIFTING
EAST MONDAY RESULTING IN WINDY PERIODS ACROSS THE AREA.

A CONTINUOUS FLOW OF MOISTURE OFF THE PACIFIC WILL MOVE ACROSS
IDAHO INTO MONTANA SUNDAY INTO MONDAY BRINGING CHANCES FOR SHOWERS
ACROSS THE PLAINS WITH SNOW LIKELY FOR THE MOUNTAINS. THERE WILL
BE A BRIEF BREAK TUESDAY BEFORE THE NEXT STORM SYSTEM IMPACTS OUR
FORECAST AREA WEDNESDAY AND THURSDAY. MODELS ARE IN PRETTY GOOD
AGREEMENT IN CARVING OUT A LARGE TROUGH ACROSS THE NORTHERN
ROCKIES WEDNESDAY AND THURSDAY...AS WELL AS PLACING AN UPPER LOW
IN OUR VICINITY. FORECASTER CONFIDENCE IS HIGH FOR A CHRISTMAS
SNOW EVENT BUT DETAILS SUCH AS SNOW AMOUNTS ARE UNCERTAIN AT THIS
TIME. HOOLEY
&&

.AVIATION...

LOW CEILINGS ALONG WITH AREAS OF DENSE FOG WILL CONTINUE TO POSE
AN AVIATION HAZARD THROUGH THIS MORNING. MVFR TO IFR CONDITIONS
WILL PREVAIL WITH AREAS OF LIFR FROM KSHR TO KBIL THROUGH 18Z. THE
EXCEPTION WILL BE THE KLVM AREA AND ADJACENT FOOTHILLS WHERE VFR
CONDITIONS WILL PREVAIL. THE MOUNTAINS WILL BE OBSCURED AT TIMES
THROUGHOUT THE DAY. HOOLEY/REIMER



&&

.PRELIMINARY POINT TEMP/POPS...

    TDY THU     FRI     SAT     SUN     MON     TUE
-------------------------------------------------------
BIL 033 023/039 023/038 027/042 026/044 035/047 027/041
    2/J 00/B    00/B    11/B    23/W    33/W    32/W
LVM 036 022/041 024/040 026/043 026/041 036/047 027/043
    3/J 01/N    11/B    21/N    23/W    33/W    33/W
HDN 031 015/037 016/037 020/040 019/041 029/044 023/040
    2/J 10/B    00/B    01/B    12/J    33/W    32/W
MLS 028 017/036 019/037 019/039 022/041 029/043 023/039
    2/J 10/B    00/B    11/B    12/J    23/W    11/B
4BQ 029 016/039 017/040 017/041 020/043 030/045 024/041
    2/J 10/B    00/B    11/B    12/J    23/W    21/B
BHK 022 015/034 018/037 017/039 020/040 027/041 021/037
    2/J 20/B    10/B    01/B    11/B    22/W    11/B
SHR 032 016/038 016/038 019/040 019/041 028/043 022/040
    2/J 00/B    10/B    12/J    12/J    34/W    32/W

&&

.BYZ WATCHES/WARNINGS/ADVISORIES...
MT...NONE.
WY...DENSE FOG ADVISORY IN EFFECT UNTIL 11 AM MST THIS MORNING FOR
      ZONE 99.

&&

$$
WEATHER.GOV/BILLINGS



000
FXUS65 KBYZ 171621
AFDBYZ

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BILLINGS MT
921 AM MST WED DEC 17 2014

.UPDATE...
AREAS OF FOG STILL ON GOING ACROSS THE REGION THIS MORNING AND
WILL CONTINUE THROUGH AT LEAST 19Z FOR MANY AREAS FROM BILLINGS
EAST. DENSE FOG WAS CONTINUING IN THE SHERIDAN AND WILL KEEP THE
DENSE FOG ADVISORY GOING THROUGH AT LEAST 18Z. WEB CAMS AND
SURFACE OBSERVATIONS ALSO INDICATED PATCHY DENSE FOG WAS LOCATED
ACROSS THE SOUTHERN AREAS OF POWDER RIVER AND CARTER COUNTIES.
PATCHY FOG ALSO EXTENDED NORTHWARD FROM THESE AREAS AND HAD PUSHED
WESTWARD INTO THE BILLINGS AREA. HRRR INDICATING FOG IN THESE
AREAS WILL BEGIN BREAKING UP BY MID MORNING AS A WARM FRONT MOVES
ACROSS THE AREA ALLOWING SOME MIXING TO TAKE PLACE.

INCREASE POPS ACROSS THE AREA THIS MORNING AS A WEAK UPPER LEVEL
CIRCULATION ALONG WITH WEAK VORTICITY WAS PRODUCING LIGHT SNOW
SHOWERS OVER THE FORECAST AREA. NO SNOW ACCUMULATIONS ARE EXPECTED
WITH THIS DISTURBANCE. DID LOWER TEMPERATURES A FEW DEGREES AS
CLOUD COVER WILL INHIBIT HEATING THIS AFTERNOON IN SPITE OF WARM
FRONT MOVING THROUGH. RICHMOND

&&

.SHORT TERM...VALID FOR TDY AND THU...

SHERIDAN WAS REPORTING DENSE FOG THIS MORNING AND AREA WEB CAMS
IN SHERIDAN ALSO SHOWED DENSE FOG. LAST FEW RUNS OF THE HRRR
TARGETED THE SHERIDAN FOOTHILLS WITH DENSE FOG AND DISSIPATED IT
BY 19Z. HAVE ISSUED A DENSE FOG ADVISORY FOR THIS AREA THROUGH
18Z. OTHER AREAS E OF KBIL WILL ALSO HAVE FOG...AND SOME OF IT MAY
BE DENSE...BUT DENSE FOG WILL NOT BE WIDESPREAD ENOUGH TO WARRANT
AN ADVISORY.

TWO SHORTWAVES WERE AFFECTING THE AREA EARLY THIS MORNING. ONE WAS
MOVING INTO SW MT AND THE OTHER WAS OVER W MT PER WATER VAPOR
IMAGERY. THESE WAVES WILL MERGE AND CROSS THE AREA TODAY THROUGH
TONIGHT. THE BEST Q-VECTOR CONVERGENCE WILL OCCUR THIS MORNING
WITH THE WAVES...AND MODELS BROUGHT A DECENT AREA OF MOISTURE
ACROSS THE AREA. DETERMINISTIC MODELS AND SREF ALL SHOWED LIGHT
WIDELY SCATTERED QPF TODAY. SO WENT WITH MAINLY SCATTERED
FLURRIES...WITH CHANCE POPS IN THE WESTERN MOUNTAINS THIS MORNING.
CHANCES FOR PRECIPITATION WILL END TONIGHT. A WARM FRONT WILL PUSH
INTO THE REGION TONIGHT AND USHER IN WARMING CONDITIONS THROUGH
THU. ANOTHER WAVE APPROACHES THU AND MOVES INTO THE AREA THU
NIGHT. PRECIPITATION CHANCES WILL BE CONFINED TO THE MOUNTAINS.

TEMPERATURES TODAY WILL BE HIGHER THAN YESTERDAY/S READINGS AND
WILL BE WARMER YET ON THU. ARTHUR

.LONG TERM...VALID FOR FRI...SAT...SUN...MON...TUE...

MODELS ARE IN DECENT AGREEMENT THROUGH THE EXTENDED PERIOD AS
THEY SHOW AN UNSETTLED PATTERN. MAIN FORECAST ISSUE WILL BE SUNDAY
INTO MONDAY AND AGAIN CHRISTMAS EVE/CHRISTMAS DAY AS THESE
PERIODS SHOW THE LIKELIHOOD OF A STORM SYSTEM IMPACTING THE AREA.
BRIEF RIDGING WILL BE OVER THE FORECAST AREA FRIDAY BEFORE A WEAK
DISTURBANCE MOVES ACROSS THE AREA FRIDAY NIGHT INTO SATURDAY
BRINGING A SLIGHT CHANCE FOR RAIN AND SNOW SHOWERS. AN UNSETTLED
NORTHWEST FLOW ALOFT WILL PREVAIL OVER THE WEEKEND RESULTING IN A
SLIGHT SHOWER CHANCE SATURDAY. LEE-SIDE TROUGHING SETS UP SUNDAY
BEFORE A COLD FRONT MOVES THROUGH MONDAY. TIGHT PRESSURE GRADIENTS
WILL BE ACROSS THE BEARTOOTH/ABSAROKA FOOTHILLS SUNDAY SHIFTING
EAST MONDAY RESULTING IN WINDY PERIODS ACROSS THE AREA.

A CONTINUOUS FLOW OF MOISTURE OFF THE PACIFIC WILL MOVE ACROSS
IDAHO INTO MONTANA SUNDAY INTO MONDAY BRINGING CHANCES FOR SHOWERS
ACROSS THE PLAINS WITH SNOW LIKELY FOR THE MOUNTAINS. THERE WILL
BE A BRIEF BREAK TUESDAY BEFORE THE NEXT STORM SYSTEM IMPACTS OUR
FORECAST AREA WEDNESDAY AND THURSDAY. MODELS ARE IN PRETTY GOOD
AGREEMENT IN CARVING OUT A LARGE TROUGH ACROSS THE NORTHERN
ROCKIES WEDNESDAY AND THURSDAY...AS WELL AS PLACING AN UPPER LOW
IN OUR VICINITY. FORECASTER CONFIDENCE IS HIGH FOR A CHRISTMAS
SNOW EVENT BUT DETAILS SUCH AS SNOW AMOUNTS ARE UNCERTAIN AT THIS
TIME. HOOLEY
&&

.AVIATION...

LOW CEILINGS ALONG WITH AREAS OF DENSE FOG WILL CONTINUE TO POSE
AN AVIATION HAZARD THROUGH THIS MORNING. MVFR TO IFR CONDITIONS
WILL PREVAIL WITH AREAS OF LIFR FROM KSHR TO KBIL THROUGH 18Z. THE
EXCEPTION WILL BE THE KLVM AREA AND ADJACENT FOOTHILLS WHERE VFR
CONDITIONS WILL PREVAIL. THE MOUNTAINS WILL BE OBSCURED AT TIMES
THROUGHOUT THE DAY. HOOLEY/REIMER



&&

.PRELIMINARY POINT TEMP/POPS...

    TDY THU     FRI     SAT     SUN     MON     TUE
-------------------------------------------------------
BIL 033 023/039 023/038 027/042 026/044 035/047 027/041
    2/J 00/B    00/B    11/B    23/W    33/W    32/W
LVM 036 022/041 024/040 026/043 026/041 036/047 027/043
    3/J 01/N    11/B    21/N    23/W    33/W    33/W
HDN 031 015/037 016/037 020/040 019/041 029/044 023/040
    2/J 10/B    00/B    01/B    12/J    33/W    32/W
MLS 028 017/036 019/037 019/039 022/041 029/043 023/039
    2/J 10/B    00/B    11/B    12/J    23/W    11/B
4BQ 029 016/039 017/040 017/041 020/043 030/045 024/041
    2/J 10/B    00/B    11/B    12/J    23/W    21/B
BHK 022 015/034 018/037 017/039 020/040 027/041 021/037
    2/J 20/B    10/B    01/B    11/B    22/W    11/B
SHR 032 016/038 016/038 019/040 019/041 028/043 022/040
    2/J 00/B    10/B    12/J    12/J    34/W    32/W

&&

.BYZ WATCHES/WARNINGS/ADVISORIES...
MT...NONE.
WY...DENSE FOG ADVISORY IN EFFECT UNTIL 11 AM MST THIS MORNING FOR
      ZONE 99.

&&

$$
WEATHER.GOV/BILLINGS




000
FXUS65 KTFX 171507
AFDTFX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREAT FALLS MT
807 AM MST Wed Dec 17 2014

.UPDATE...
Dense freezing fog is no longer expected over Cascade and Judith
Basin Counties so the freezing fog advisory for those counties has
been cancelled.

&&

.AVIATION...
UPDATED 1209Z.
Light snow has ended across most of Central Montana although
northeastern portions, near and east of KHVR and KLWT, continue to
see light snow. Winds will remain light today and areas of fog, and
some dense freezing fog along northern portions of the region, will
continue into the morning. Widespread IFR conditions will continue
into late morning near KCTB.

&&

.PREV DISCUSSION...
/ISSUED 510 AM MST Wed Dec 17 2014/

Tonight through Friday...Central Montana is underneath an area of
weak cyclonic flow aloft. Precipitation associated with a
disturbance in this flow will move east of the zones today. A weak
trof over over the Eastern Pacific will move over the Pacific
Northwest today and the zones will be underneath the southwest flow
ahead of this system. Flow aloft and dynamics will remain weak,
however. Models show very little warming of the airmass yet raise
temperatures from yesterday. With cloud cover and, possibly, areas
of fog, not convinced that all of that warming will occur and will
moderate high temps somewhat. The airmass will remain unsettled
Thursday as the trof over the Eastern Pacific slowly moves east and
and approaches the zones. Little chance of precipitation is expected
with this system. The Rockies and mountains of Southwest Montana
will have the best chance for snow although accumulations will
remain low. Zelzer

Friday Night through Wednesday...A weak shortwave trough will move
through Montana Friday night into Saturday, bringing just a chance
of snow to the mountains. Forecast models continue to indicate that
the pattern will then change for Saturday night through Tuesday. An
upper level high pressure ridge will strengthen off the California
coast and a low pressure trough will deepen from Hudson Bay into the
Great Lakes. This will result in Montana being under a strong
northwesterly flow aloft. The models indicate that the strongest
winds aloft will occur Sunday into Sunday night with the passage of
a disturbance embedded in the flow. However, the models differ on
just how strong these winds will be. The ECMWF only forecasts winds
of 45 to 55 kts at 700 mb, while the GFS generally has 60 to 70 kt
winds. Have therefore used a compromise solution between these two
models with regards to surface wind strength. Despite this
difference, this set-up will bring gusty westerly downslope winds to
much of the area, but especially over the plains of north central
Montana. In fact, some areas along the Rocky Mountain Front could
approach High Wind criteria (40 mph sustained/58 mph gusts).
Confidence remains moderate that High Wind highlights may be needed
for this event. The only concern is that the northwesterly wind
direction is not as favorable for widespread High Winds. There is
also significant moisture with this disturbance, so have continued
to spread the chance for precipitation out onto the plains. Winds
aloft will decrease somewhat after the passage of the disturbance,
but the northwesterly flow aloft will remain fairly moist, so have
kept the chance for precipitation above climatological normals
across the area into Tuesday. A potentially significant weather
system originating in the Gulf of Alaska is then forecast to move
into Montana Tuesday into Wednesday, bringing a very good chance of
precipitation. Because this feature is near the end of the period,
exact timing and types of precipitation are very uncertain.
Regardless, this system will need to be monitored for potential
winter weather highlights, especially considering that it would be
moving into the area during peak holiday travel time. The breezy
winds through Monday will keep temperatures around 10 degrees above
normal. The warmest day of the period appears to be Monday, when
most lower elevation locations should get well into the 40s.
However, with the system moving into the area at the end of the
period, temperatures will likely fall back to near or slightly below
seasonal averages by Wednesday.
Coulston

&&

.PRELIMINARY POINT TEMPS/POPS...
GTF  35  24  38  26 /  20  10  10  10
CTB  32  21  37  24 /  10  10  10  10
HLN  33  17  33  19 /  20  10  20  10
BZN  28  12  30  14 /  40  10  10  10
WEY  32  16  30  18 /  30  20  20  20
DLN  31  16  33  19 /  10  10  20  10
HVR  29  19  36  21 /  30  10  10  10
LWT  36  22  41  24 /  40  10  10  10

&&

.TFX WATCHES/WARNINGS/ADVISORIES...
FREEZING FOG ADVISORY until 11 AM MST this morning Eastern
Teton...Southern Rocky Mountain Front.

FREEZING FOG ADVISORY until 11 AM MST this morning Eastern
Glacier...Eastern Pondera...Northern Rocky Mountain Front...
Toole.

&&

$$

weather.gov/greatfalls
www.twitter.com/NWSGreatFalls
www.facebook.com/NWSGreatFalls






000
FXUS65 KTFX 171507
AFDTFX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREAT FALLS MT
807 AM MST Wed Dec 17 2014

.UPDATE...
Dense freezing fog is no longer expected over Cascade and Judith
Basin Counties so the freezing fog advisory for those counties has
been cancelled.

&&

.AVIATION...
UPDATED 1209Z.
Light snow has ended across most of Central Montana although
northeastern portions, near and east of KHVR and KLWT, continue to
see light snow. Winds will remain light today and areas of fog, and
some dense freezing fog along northern portions of the region, will
continue into the morning. Widespread IFR conditions will continue
into late morning near KCTB.

&&

.PREV DISCUSSION...
/ISSUED 510 AM MST Wed Dec 17 2014/

Tonight through Friday...Central Montana is underneath an area of
weak cyclonic flow aloft. Precipitation associated with a
disturbance in this flow will move east of the zones today. A weak
trof over over the Eastern Pacific will move over the Pacific
Northwest today and the zones will be underneath the southwest flow
ahead of this system. Flow aloft and dynamics will remain weak,
however. Models show very little warming of the airmass yet raise
temperatures from yesterday. With cloud cover and, possibly, areas
of fog, not convinced that all of that warming will occur and will
moderate high temps somewhat. The airmass will remain unsettled
Thursday as the trof over the Eastern Pacific slowly moves east and
and approaches the zones. Little chance of precipitation is expected
with this system. The Rockies and mountains of Southwest Montana
will have the best chance for snow although accumulations will
remain low. Zelzer

Friday Night through Wednesday...A weak shortwave trough will move
through Montana Friday night into Saturday, bringing just a chance
of snow to the mountains. Forecast models continue to indicate that
the pattern will then change for Saturday night through Tuesday. An
upper level high pressure ridge will strengthen off the California
coast and a low pressure trough will deepen from Hudson Bay into the
Great Lakes. This will result in Montana being under a strong
northwesterly flow aloft. The models indicate that the strongest
winds aloft will occur Sunday into Sunday night with the passage of
a disturbance embedded in the flow. However, the models differ on
just how strong these winds will be. The ECMWF only forecasts winds
of 45 to 55 kts at 700 mb, while the GFS generally has 60 to 70 kt
winds. Have therefore used a compromise solution between these two
models with regards to surface wind strength. Despite this
difference, this set-up will bring gusty westerly downslope winds to
much of the area, but especially over the plains of north central
Montana. In fact, some areas along the Rocky Mountain Front could
approach High Wind criteria (40 mph sustained/58 mph gusts).
Confidence remains moderate that High Wind highlights may be needed
for this event. The only concern is that the northwesterly wind
direction is not as favorable for widespread High Winds. There is
also significant moisture with this disturbance, so have continued
to spread the chance for precipitation out onto the plains. Winds
aloft will decrease somewhat after the passage of the disturbance,
but the northwesterly flow aloft will remain fairly moist, so have
kept the chance for precipitation above climatological normals
across the area into Tuesday. A potentially significant weather
system originating in the Gulf of Alaska is then forecast to move
into Montana Tuesday into Wednesday, bringing a very good chance of
precipitation. Because this feature is near the end of the period,
exact timing and types of precipitation are very uncertain.
Regardless, this system will need to be monitored for potential
winter weather highlights, especially considering that it would be
moving into the area during peak holiday travel time. The breezy
winds through Monday will keep temperatures around 10 degrees above
normal. The warmest day of the period appears to be Monday, when
most lower elevation locations should get well into the 40s.
However, with the system moving into the area at the end of the
period, temperatures will likely fall back to near or slightly below
seasonal averages by Wednesday.
Coulston

&&

.PRELIMINARY POINT TEMPS/POPS...
GTF  35  24  38  26 /  20  10  10  10
CTB  32  21  37  24 /  10  10  10  10
HLN  33  17  33  19 /  20  10  20  10
BZN  28  12  30  14 /  40  10  10  10
WEY  32  16  30  18 /  30  20  20  20
DLN  31  16  33  19 /  10  10  20  10
HVR  29  19  36  21 /  30  10  10  10
LWT  36  22  41  24 /  40  10  10  10

&&

.TFX WATCHES/WARNINGS/ADVISORIES...
FREEZING FOG ADVISORY until 11 AM MST this morning Eastern
Teton...Southern Rocky Mountain Front.

FREEZING FOG ADVISORY until 11 AM MST this morning Eastern
Glacier...Eastern Pondera...Northern Rocky Mountain Front...
Toole.

&&

$$

weather.gov/greatfalls
www.twitter.com/NWSGreatFalls
www.facebook.com/NWSGreatFalls






000
FXUS65 KTFX 171507
AFDTFX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREAT FALLS MT
807 AM MST Wed Dec 17 2014

.UPDATE...
Dense freezing fog is no longer expected over Cascade and Judith
Basin Counties so the freezing fog advisory for those counties has
been cancelled.

&&

.AVIATION...
UPDATED 1209Z.
Light snow has ended across most of Central Montana although
northeastern portions, near and east of KHVR and KLWT, continue to
see light snow. Winds will remain light today and areas of fog, and
some dense freezing fog along northern portions of the region, will
continue into the morning. Widespread IFR conditions will continue
into late morning near KCTB.

&&

.PREV DISCUSSION...
/ISSUED 510 AM MST Wed Dec 17 2014/

Tonight through Friday...Central Montana is underneath an area of
weak cyclonic flow aloft. Precipitation associated with a
disturbance in this flow will move east of the zones today. A weak
trof over over the Eastern Pacific will move over the Pacific
Northwest today and the zones will be underneath the southwest flow
ahead of this system. Flow aloft and dynamics will remain weak,
however. Models show very little warming of the airmass yet raise
temperatures from yesterday. With cloud cover and, possibly, areas
of fog, not convinced that all of that warming will occur and will
moderate high temps somewhat. The airmass will remain unsettled
Thursday as the trof over the Eastern Pacific slowly moves east and
and approaches the zones. Little chance of precipitation is expected
with this system. The Rockies and mountains of Southwest Montana
will have the best chance for snow although accumulations will
remain low. Zelzer

Friday Night through Wednesday...A weak shortwave trough will move
through Montana Friday night into Saturday, bringing just a chance
of snow to the mountains. Forecast models continue to indicate that
the pattern will then change for Saturday night through Tuesday. An
upper level high pressure ridge will strengthen off the California
coast and a low pressure trough will deepen from Hudson Bay into the
Great Lakes. This will result in Montana being under a strong
northwesterly flow aloft. The models indicate that the strongest
winds aloft will occur Sunday into Sunday night with the passage of
a disturbance embedded in the flow. However, the models differ on
just how strong these winds will be. The ECMWF only forecasts winds
of 45 to 55 kts at 700 mb, while the GFS generally has 60 to 70 kt
winds. Have therefore used a compromise solution between these two
models with regards to surface wind strength. Despite this
difference, this set-up will bring gusty westerly downslope winds to
much of the area, but especially over the plains of north central
Montana. In fact, some areas along the Rocky Mountain Front could
approach High Wind criteria (40 mph sustained/58 mph gusts).
Confidence remains moderate that High Wind highlights may be needed
for this event. The only concern is that the northwesterly wind
direction is not as favorable for widespread High Winds. There is
also significant moisture with this disturbance, so have continued
to spread the chance for precipitation out onto the plains. Winds
aloft will decrease somewhat after the passage of the disturbance,
but the northwesterly flow aloft will remain fairly moist, so have
kept the chance for precipitation above climatological normals
across the area into Tuesday. A potentially significant weather
system originating in the Gulf of Alaska is then forecast to move
into Montana Tuesday into Wednesday, bringing a very good chance of
precipitation. Because this feature is near the end of the period,
exact timing and types of precipitation are very uncertain.
Regardless, this system will need to be monitored for potential
winter weather highlights, especially considering that it would be
moving into the area during peak holiday travel time. The breezy
winds through Monday will keep temperatures around 10 degrees above
normal. The warmest day of the period appears to be Monday, when
most lower elevation locations should get well into the 40s.
However, with the system moving into the area at the end of the
period, temperatures will likely fall back to near or slightly below
seasonal averages by Wednesday.
Coulston

&&

.PRELIMINARY POINT TEMPS/POPS...
GTF  35  24  38  26 /  20  10  10  10
CTB  32  21  37  24 /  10  10  10  10
HLN  33  17  33  19 /  20  10  20  10
BZN  28  12  30  14 /  40  10  10  10
WEY  32  16  30  18 /  30  20  20  20
DLN  31  16  33  19 /  10  10  20  10
HVR  29  19  36  21 /  30  10  10  10
LWT  36  22  41  24 /  40  10  10  10

&&

.TFX WATCHES/WARNINGS/ADVISORIES...
FREEZING FOG ADVISORY until 11 AM MST this morning Eastern
Teton...Southern Rocky Mountain Front.

FREEZING FOG ADVISORY until 11 AM MST this morning Eastern
Glacier...Eastern Pondera...Northern Rocky Mountain Front...
Toole.

&&

$$

weather.gov/greatfalls
www.twitter.com/NWSGreatFalls
www.facebook.com/NWSGreatFalls






000
FXUS65 KTFX 171507
AFDTFX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREAT FALLS MT
807 AM MST Wed Dec 17 2014

.UPDATE...
Dense freezing fog is no longer expected over Cascade and Judith
Basin Counties so the freezing fog advisory for those counties has
been cancelled.

&&

.AVIATION...
UPDATED 1209Z.
Light snow has ended across most of Central Montana although
northeastern portions, near and east of KHVR and KLWT, continue to
see light snow. Winds will remain light today and areas of fog, and
some dense freezing fog along northern portions of the region, will
continue into the morning. Widespread IFR conditions will continue
into late morning near KCTB.

&&

.PREV DISCUSSION...
/ISSUED 510 AM MST Wed Dec 17 2014/

Tonight through Friday...Central Montana is underneath an area of
weak cyclonic flow aloft. Precipitation associated with a
disturbance in this flow will move east of the zones today. A weak
trof over over the Eastern Pacific will move over the Pacific
Northwest today and the zones will be underneath the southwest flow
ahead of this system. Flow aloft and dynamics will remain weak,
however. Models show very little warming of the airmass yet raise
temperatures from yesterday. With cloud cover and, possibly, areas
of fog, not convinced that all of that warming will occur and will
moderate high temps somewhat. The airmass will remain unsettled
Thursday as the trof over the Eastern Pacific slowly moves east and
and approaches the zones. Little chance of precipitation is expected
with this system. The Rockies and mountains of Southwest Montana
will have the best chance for snow although accumulations will
remain low. Zelzer

Friday Night through Wednesday...A weak shortwave trough will move
through Montana Friday night into Saturday, bringing just a chance
of snow to the mountains. Forecast models continue to indicate that
the pattern will then change for Saturday night through Tuesday. An
upper level high pressure ridge will strengthen off the California
coast and a low pressure trough will deepen from Hudson Bay into the
Great Lakes. This will result in Montana being under a strong
northwesterly flow aloft. The models indicate that the strongest
winds aloft will occur Sunday into Sunday night with the passage of
a disturbance embedded in the flow. However, the models differ on
just how strong these winds will be. The ECMWF only forecasts winds
of 45 to 55 kts at 700 mb, while the GFS generally has 60 to 70 kt
winds. Have therefore used a compromise solution between these two
models with regards to surface wind strength. Despite this
difference, this set-up will bring gusty westerly downslope winds to
much of the area, but especially over the plains of north central
Montana. In fact, some areas along the Rocky Mountain Front could
approach High Wind criteria (40 mph sustained/58 mph gusts).
Confidence remains moderate that High Wind highlights may be needed
for this event. The only concern is that the northwesterly wind
direction is not as favorable for widespread High Winds. There is
also significant moisture with this disturbance, so have continued
to spread the chance for precipitation out onto the plains. Winds
aloft will decrease somewhat after the passage of the disturbance,
but the northwesterly flow aloft will remain fairly moist, so have
kept the chance for precipitation above climatological normals
across the area into Tuesday. A potentially significant weather
system originating in the Gulf of Alaska is then forecast to move
into Montana Tuesday into Wednesday, bringing a very good chance of
precipitation. Because this feature is near the end of the period,
exact timing and types of precipitation are very uncertain.
Regardless, this system will need to be monitored for potential
winter weather highlights, especially considering that it would be
moving into the area during peak holiday travel time. The breezy
winds through Monday will keep temperatures around 10 degrees above
normal. The warmest day of the period appears to be Monday, when
most lower elevation locations should get well into the 40s.
However, with the system moving into the area at the end of the
period, temperatures will likely fall back to near or slightly below
seasonal averages by Wednesday.
Coulston

&&

.PRELIMINARY POINT TEMPS/POPS...
GTF  35  24  38  26 /  20  10  10  10
CTB  32  21  37  24 /  10  10  10  10
HLN  33  17  33  19 /  20  10  20  10
BZN  28  12  30  14 /  40  10  10  10
WEY  32  16  30  18 /  30  20  20  20
DLN  31  16  33  19 /  10  10  20  10
HVR  29  19  36  21 /  30  10  10  10
LWT  36  22  41  24 /  40  10  10  10

&&

.TFX WATCHES/WARNINGS/ADVISORIES...
FREEZING FOG ADVISORY until 11 AM MST this morning Eastern
Teton...Southern Rocky Mountain Front.

FREEZING FOG ADVISORY until 11 AM MST this morning Eastern
Glacier...Eastern Pondera...Northern Rocky Mountain Front...
Toole.

&&

$$

weather.gov/greatfalls
www.twitter.com/NWSGreatFalls
www.facebook.com/NWSGreatFalls






000
FXUS65 KTFX 171210
AFDTFX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREAT FALLS MT
510 AM MST Wed Dec 17 2014

.DISCUSSION...

Tonight through Friday...Central Montana is underneath an area of
weak cyclonic flow aloft. Precipitation associated with a
disturbance in this flow will move east of the zones today. A weak
trof over over the Eastern Pacific will move over the Pacific
Northwest today and the zones will be underneath the southwest flow
ahead of this system. Flow aloft and dynamics will remain weak,
however. Models show very little warming of the airmass yet raise
temperatures from yesterday. With cloud cover and, possibly, areas
of fog, not convinced that all of that warming will occur and will
moderate high temps somewhat. The airmass will remain unsettled
Thursday as the trof over the Eastern Pacific slowly moves east and
and approaches the zones. Little chance of precipitation is expected
with this system. The Rockies and mountains of Southwest Montana
will have the best chance for snow although accumulations will
remain low. Zelzer

Friday Night through Wednesday...A weak shortwave trough will move
through Montana Friday night into Saturday, bringing just a chance
of snow to the mountains. Forecast models continue to indicate that
the pattern will then change for Saturday night through Tuesday. An
upper level high pressure ridge will strengthen off the California
coast and a low pressure trough will deepen from Hudson Bay into the
Great Lakes. This will result in Montana being under a strong
northwesterly flow aloft. The models indicate that the strongest
winds aloft will occur Sunday into Sunday night with the passage of
a disturbance embedded in the flow. However, the models differ on
just how strong these winds will be. The ECMWF only forecasts winds
of 45 to 55 kts at 700 mb, while the GFS generally has 60 to 70 kt
winds. Have therefore used a compromise solution between these two
models with regards to surface wind strength. Despite this
difference, this set-up will bring gusty westerly downslope winds to
much of the area, but especially over the plains of north central
Montana. In fact, some areas along the Rocky Mountain Front could
approach High Wind criteria (40 mph sustained/58 mph gusts).
Confidence remains moderate that High Wind highlights may be needed
for this event. The only concern is that the northwesterly wind
direction is not as favorable for widespread High Winds. There is
also significant moisture with this disturbance, so have continued
to spread the chance for precipitation out onto the plains. Winds
aloft will decrease somewhat after the passage of the disturbance,
but the northwesterly flow aloft will remain fairly moist, so have
kept the chance for precipitation above climatological normals
across the area into Tuesday. A potentially significant weather
system originating in the Gulf of Alaska is then forecast to move
into Montana Tuesday into Wednesday, bringing a very good chance of
precipitation. Because this feature is near the end of the period,
exact timing and types of precipitation are very uncertain.
Regardless, this system will need to be monitored for potential
winter weather highlights, especially considering that it would be
moving into the area during peak holiday travel time. The breezy
winds through Monday will keep temperatures around 10 degrees above
normal. The warmest day of the period appears to be Monday, when
most lower elevation locations should get well into the 40s.
However, with the system moving into the area at the end of the
period, temperatures will likely fall back to near or slightly below
seasonal averages by Wednesday.
Coulston

&&

.AVIATION...
UPDATED 1209Z.
Light snow has ended across most of Central Montana although
northeastern portions, near and east of KHVR and KLWT, continue to
see light snow. Winds will remain light today and areas of fog, and
some dense freezing fog along northern portions of the region, will
continue into the morning. Widespread IFR conditions will continue
into late morning near KCTB.

&&

.PRELIMINARY POINT TEMPS/POPS...
GTF  35  24  38  26 /  20  10  10  10
CTB  32  21  37  24 /  10  10  10  10
HLN  33  17  33  19 /  20  10  20  10
BZN  28  12  30  14 /  40  10  10  10
WEY  32  16  30  18 /  30  20  20  20
DLN  31  16  33  19 /  10  10  20  10
HVR  29  19  36  21 /  30  10  10  10
LWT  36  22  41  24 /  40  10  10  10

&&

.TFX WATCHES/WARNINGS/ADVISORIES...
FREEZING FOG ADVISORY until 11 AM MST this morning Cascade...
Eastern Teton...Judith Basin...Southern Rocky Mountain Front.

FREEZING FOG ADVISORY until 11 AM MST this morning Eastern
Glacier...Eastern Pondera...Northern Rocky Mountain Front...
Toole.

&&

$$

weather.gov/greatfalls
www.twitter.com/NWSGreatFalls
www.facebook.com/NWSGreatFalls







000
FXUS65 KTFX 171210
AFDTFX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREAT FALLS MT
510 AM MST Wed Dec 17 2014

.DISCUSSION...

Tonight through Friday...Central Montana is underneath an area of
weak cyclonic flow aloft. Precipitation associated with a
disturbance in this flow will move east of the zones today. A weak
trof over over the Eastern Pacific will move over the Pacific
Northwest today and the zones will be underneath the southwest flow
ahead of this system. Flow aloft and dynamics will remain weak,
however. Models show very little warming of the airmass yet raise
temperatures from yesterday. With cloud cover and, possibly, areas
of fog, not convinced that all of that warming will occur and will
moderate high temps somewhat. The airmass will remain unsettled
Thursday as the trof over the Eastern Pacific slowly moves east and
and approaches the zones. Little chance of precipitation is expected
with this system. The Rockies and mountains of Southwest Montana
will have the best chance for snow although accumulations will
remain low. Zelzer

Friday Night through Wednesday...A weak shortwave trough will move
through Montana Friday night into Saturday, bringing just a chance
of snow to the mountains. Forecast models continue to indicate that
the pattern will then change for Saturday night through Tuesday. An
upper level high pressure ridge will strengthen off the California
coast and a low pressure trough will deepen from Hudson Bay into the
Great Lakes. This will result in Montana being under a strong
northwesterly flow aloft. The models indicate that the strongest
winds aloft will occur Sunday into Sunday night with the passage of
a disturbance embedded in the flow. However, the models differ on
just how strong these winds will be. The ECMWF only forecasts winds
of 45 to 55 kts at 700 mb, while the GFS generally has 60 to 70 kt
winds. Have therefore used a compromise solution between these two
models with regards to surface wind strength. Despite this
difference, this set-up will bring gusty westerly downslope winds to
much of the area, but especially over the plains of north central
Montana. In fact, some areas along the Rocky Mountain Front could
approach High Wind criteria (40 mph sustained/58 mph gusts).
Confidence remains moderate that High Wind highlights may be needed
for this event. The only concern is that the northwesterly wind
direction is not as favorable for widespread High Winds. There is
also significant moisture with this disturbance, so have continued
to spread the chance for precipitation out onto the plains. Winds
aloft will decrease somewhat after the passage of the disturbance,
but the northwesterly flow aloft will remain fairly moist, so have
kept the chance for precipitation above climatological normals
across the area into Tuesday. A potentially significant weather
system originating in the Gulf of Alaska is then forecast to move
into Montana Tuesday into Wednesday, bringing a very good chance of
precipitation. Because this feature is near the end of the period,
exact timing and types of precipitation are very uncertain.
Regardless, this system will need to be monitored for potential
winter weather highlights, especially considering that it would be
moving into the area during peak holiday travel time. The breezy
winds through Monday will keep temperatures around 10 degrees above
normal. The warmest day of the period appears to be Monday, when
most lower elevation locations should get well into the 40s.
However, with the system moving into the area at the end of the
period, temperatures will likely fall back to near or slightly below
seasonal averages by Wednesday.
Coulston

&&

.AVIATION...
UPDATED 1209Z.
Light snow has ended across most of Central Montana although
northeastern portions, near and east of KHVR and KLWT, continue to
see light snow. Winds will remain light today and areas of fog, and
some dense freezing fog along northern portions of the region, will
continue into the morning. Widespread IFR conditions will continue
into late morning near KCTB.

&&

.PRELIMINARY POINT TEMPS/POPS...
GTF  35  24  38  26 /  20  10  10  10
CTB  32  21  37  24 /  10  10  10  10
HLN  33  17  33  19 /  20  10  20  10
BZN  28  12  30  14 /  40  10  10  10
WEY  32  16  30  18 /  30  20  20  20
DLN  31  16  33  19 /  10  10  20  10
HVR  29  19  36  21 /  30  10  10  10
LWT  36  22  41  24 /  40  10  10  10

&&

.TFX WATCHES/WARNINGS/ADVISORIES...
FREEZING FOG ADVISORY until 11 AM MST this morning Cascade...
Eastern Teton...Judith Basin...Southern Rocky Mountain Front.

FREEZING FOG ADVISORY until 11 AM MST this morning Eastern
Glacier...Eastern Pondera...Northern Rocky Mountain Front...
Toole.

&&

$$

weather.gov/greatfalls
www.twitter.com/NWSGreatFalls
www.facebook.com/NWSGreatFalls








000
FXUS65 KMSO 171046
AFDMSO

Area Forecast Discussion
National Weather Service Missoula MT
346 AM MST WED DEC 17 2014

.DISCUSSION...A series of weak weather disturbances will approach
from the Pacific NW through the rest of the week. Periods of light
snow in the mountains can be expected through Thursday. Travel
impacts will be minimal due to the light nature of the
precipitation.  Otherwise weather conditions will remain cloudy
throughout Western Montana and central Idaho. Late Friday into
Saturday morning a more moist system will move through. There
could be a better chance of accumulating snow with this system,
though only a couple inches at most is expected on the mountain
passes along the Idaho border.

During the day, the Northern Rockies will have a weak ridge of
high pressure moving through the area causing a slight drying
trend. Then on Saturday night a stream of very moist and fairly
warm air will move into the Northern Rockies. Snow levels will be
steadily rising through at least Sunday, but at the onset of
precipitation the mountain passes could receive several inches of
snow by Sunday morning. The widespread moderate to heavy
precipitation is anticipated to last through at least Sunday
night.

The Riggins/Camas Prairie region could experience gusty southerly
winds on Saturday night, but the intensity is a little uncertain
at this time. A strong jet stream will be over the Northern
Rockies starting Sunday and last through at least mid week. Monday
appears to have the best combination of strong upper level winds
and unstable conditions so be prepared for breezy to windy
conditions, especially across Lemhi county into southwest Montana.

The models are still trending towards a potential arctic around
Wednesday and Christmas day, but the strength and timing is still
uncertain. This system could produce significant travel impacts
to the area, so stay tune for further updates.

&&

.AVIATION...Light snow showers have exited areas around KBTM this
morning. Mid-level cloud deck will persist throughout western
Montana and north-central Idaho through the day today. Winds will
be light and variable for all aviation sites.


&&

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

$$





000
FXUS65 KMSO 171046
AFDMSO

Area Forecast Discussion
National Weather Service Missoula MT
346 AM MST WED DEC 17 2014

.DISCUSSION...A series of weak weather disturbances will approach
from the Pacific NW through the rest of the week. Periods of light
snow in the mountains can be expected through Thursday. Travel
impacts will be minimal due to the light nature of the
precipitation.  Otherwise weather conditions will remain cloudy
throughout Western Montana and central Idaho. Late Friday into
Saturday morning a more moist system will move through. There
could be a better chance of accumulating snow with this system,
though only a couple inches at most is expected on the mountain
passes along the Idaho border.

During the day, the Northern Rockies will have a weak ridge of
high pressure moving through the area causing a slight drying
trend. Then on Saturday night a stream of very moist and fairly
warm air will move into the Northern Rockies. Snow levels will be
steadily rising through at least Sunday, but at the onset of
precipitation the mountain passes could receive several inches of
snow by Sunday morning. The widespread moderate to heavy
precipitation is anticipated to last through at least Sunday
night.

The Riggins/Camas Prairie region could experience gusty southerly
winds on Saturday night, but the intensity is a little uncertain
at this time. A strong jet stream will be over the Northern
Rockies starting Sunday and last through at least mid week. Monday
appears to have the best combination of strong upper level winds
and unstable conditions so be prepared for breezy to windy
conditions, especially across Lemhi county into southwest Montana.

The models are still trending towards a potential arctic around
Wednesday and Christmas day, but the strength and timing is still
uncertain. This system could produce significant travel impacts
to the area, so stay tune for further updates.

&&

.AVIATION...Light snow showers have exited areas around KBTM this
morning. Mid-level cloud deck will persist throughout western
Montana and north-central Idaho through the day today. Winds will
be light and variable for all aviation sites.


&&

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

$$




000
FXUS65 KTFX 171032
AFDTFX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREAT FALLS MT
332 AM MST Wed Dec 17 2014

.DISCUSSION...

Tonight through Friday...Central Montana is underneath an area of
weak cyclonic flow aloft. Precipitation associated with a
disturbance in this flow will move east of the zones today. A weak
trof over over the Eastern Pacific will move over the Pacific
Northwest today and the zones will be underneath the southwest flow
ahead of this system. Flow aloft and dynamics will remain weak,
however. Models show very little warming of the airmass yet raise
temperatures from yesterday. With cloud cover and, possibly, areas
of fog, not convinced that all of that warming will occur and will
moderate high temps somewhat. The airmass will remain unsettled
Thursday as the trof over the Eastern Pacific slowly moves east and
and approaches the zones. Little chance of precipitation is expected
with this system. The Rockies and mountains of Southwest Montana
will have the best chance for snow although accumulations will
remain low. Zelzer

Friday Night through Wednesday...A weak shortwave trough will move
through Montana Friday night into Saturday, bringing just a chance
of snow to the mountains. Forecast models continue to indicate that
the pattern will then change for Saturday night through Tuesday. An
upper level high pressure ridge will strengthen off the California
coast and a low pressure trough will deepen from Hudson Bay into the
Great Lakes. This will result in Montana being under a strong
northwesterly flow aloft. The models indicate that the strongest
winds aloft will occur Sunday into Sunday night with the passage of
a disturbance embedded in the flow. However, the models differ on
just how strong these winds will be. The ECMWF only forecasts winds
of 45 to 55 kts at 700 mb, while the GFS generally has 60 to 70 kt
winds. Have therefore used a compromise solution between these two
models with regards to surface wind strength. Despite this
difference, this set-up will bring gusty westerly downslope winds to
much of the area, but especially over the plains of north central
Montana. In fact, some areas along the Rocky Mountain Front could
approach High Wind criteria (40 mph sustained/58 mph gusts).
Confidence remains moderate that High Wind highlights may be needed
for this event. The only concern is that the northwesterly wind
direction is not as favorable for widespread High Winds. There is
also significant moisture with this disturbance, so have continued
to spread the chance for precipitation out onto the plains. Winds
aloft will decrease somewhat after the passage of the disturbance,
but the northwesterly flow aloft will remain fairly moist, so have
kept the chance for precipitation above climatological normals
across the area into Tuesday. A potentially significant weather
system originating in the Gulf of Alaska is then forecast to move
into Montana Tuesday into Wednesday, bringing a very good chance of
precipitation. Because this feature is near the end of the period,
exact timing and types of precipitation are very uncertain.
Regardless, this system will need to be monitored for potential
winter weather highlights, especially considering that it would be
moving into the area during peak holiday travel time. The breezy
winds through Monday will keep temperatures around 10 degrees above
normal. The warmest day of the period appears to be Monday, when
most lower elevation locations should get well into the 40s.
However, with the system moving into the area at the end of the
period, temperatures will likely fall back to near or slightly below
seasonal averages by Wednesday.
Coulston

&&

.AVIATION...
UPDATED 0545Z.
Light snow continues to push northward from Southwest MT into
Central MT. Expect visibilities to generally be 2SM in areas of snow
along with mountains obscured. There is only a small chance the snow
will make into the Great Falls and Havre areas. Areas of dense fog
will continue to affect the Cut Bank area until Wednesday morning.
Expect VFR conditions to develop over much of the region on
Wednesday afternoon...as southwesterly winds start to develop. Brusda

&&

.PRELIMINARY POINT TEMPS/POPS...
GTF  35  24  38  26 /  20  10  10  10
CTB  32  21  37  24 /  10  10  10  10
HLN  33  17  33  19 /  20  10  20  10
BZN  28  12  30  14 /  40  10  10  10
WEY  32  16  30  18 /  30  20  20  20
DLN  31  16  33  19 /  10  10  20  10
HVR  29  19  36  21 /  30  10  10  10
LWT  36  22  41  24 /  40  10  10  10

&&

.TFX WATCHES/WARNINGS/ADVISORIES...
FREEZING FOG ADVISORY until 11 AM MST this morning Cascade...
Eastern Teton...Judith Basin...Southern Rocky Mountain Front.

FREEZING FOG ADVISORY until 11 AM MST this morning Eastern
Glacier...Eastern Pondera...Northern Rocky Mountain Front...
Toole.

&&

$$

weather.gov/greatfalls
www.twitter.com/NWSGreatFalls
www.facebook.com/NWSGreatFalls






000
FXUS65 KTFX 171032
AFDTFX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREAT FALLS MT
332 AM MST Wed Dec 17 2014

.DISCUSSION...

Tonight through Friday...Central Montana is underneath an area of
weak cyclonic flow aloft. Precipitation associated with a
disturbance in this flow will move east of the zones today. A weak
trof over over the Eastern Pacific will move over the Pacific
Northwest today and the zones will be underneath the southwest flow
ahead of this system. Flow aloft and dynamics will remain weak,
however. Models show very little warming of the airmass yet raise
temperatures from yesterday. With cloud cover and, possibly, areas
of fog, not convinced that all of that warming will occur and will
moderate high temps somewhat. The airmass will remain unsettled
Thursday as the trof over the Eastern Pacific slowly moves east and
and approaches the zones. Little chance of precipitation is expected
with this system. The Rockies and mountains of Southwest Montana
will have the best chance for snow although accumulations will
remain low. Zelzer

Friday Night through Wednesday...A weak shortwave trough will move
through Montana Friday night into Saturday, bringing just a chance
of snow to the mountains. Forecast models continue to indicate that
the pattern will then change for Saturday night through Tuesday. An
upper level high pressure ridge will strengthen off the California
coast and a low pressure trough will deepen from Hudson Bay into the
Great Lakes. This will result in Montana being under a strong
northwesterly flow aloft. The models indicate that the strongest
winds aloft will occur Sunday into Sunday night with the passage of
a disturbance embedded in the flow. However, the models differ on
just how strong these winds will be. The ECMWF only forecasts winds
of 45 to 55 kts at 700 mb, while the GFS generally has 60 to 70 kt
winds. Have therefore used a compromise solution between these two
models with regards to surface wind strength. Despite this
difference, this set-up will bring gusty westerly downslope winds to
much of the area, but especially over the plains of north central
Montana. In fact, some areas along the Rocky Mountain Front could
approach High Wind criteria (40 mph sustained/58 mph gusts).
Confidence remains moderate that High Wind highlights may be needed
for this event. The only concern is that the northwesterly wind
direction is not as favorable for widespread High Winds. There is
also significant moisture with this disturbance, so have continued
to spread the chance for precipitation out onto the plains. Winds
aloft will decrease somewhat after the passage of the disturbance,
but the northwesterly flow aloft will remain fairly moist, so have
kept the chance for precipitation above climatological normals
across the area into Tuesday. A potentially significant weather
system originating in the Gulf of Alaska is then forecast to move
into Montana Tuesday into Wednesday, bringing a very good chance of
precipitation. Because this feature is near the end of the period,
exact timing and types of precipitation are very uncertain.
Regardless, this system will need to be monitored for potential
winter weather highlights, especially considering that it would be
moving into the area during peak holiday travel time. The breezy
winds through Monday will keep temperatures around 10 degrees above
normal. The warmest day of the period appears to be Monday, when
most lower elevation locations should get well into the 40s.
However, with the system moving into the area at the end of the
period, temperatures will likely fall back to near or slightly below
seasonal averages by Wednesday.
Coulston

&&

.AVIATION...
UPDATED 0545Z.
Light snow continues to push northward from Southwest MT into
Central MT. Expect visibilities to generally be 2SM in areas of snow
along with mountains obscured. There is only a small chance the snow
will make into the Great Falls and Havre areas. Areas of dense fog
will continue to affect the Cut Bank area until Wednesday morning.
Expect VFR conditions to develop over much of the region on
Wednesday afternoon...as southwesterly winds start to develop. Brusda

&&

.PRELIMINARY POINT TEMPS/POPS...
GTF  35  24  38  26 /  20  10  10  10
CTB  32  21  37  24 /  10  10  10  10
HLN  33  17  33  19 /  20  10  20  10
BZN  28  12  30  14 /  40  10  10  10
WEY  32  16  30  18 /  30  20  20  20
DLN  31  16  33  19 /  10  10  20  10
HVR  29  19  36  21 /  30  10  10  10
LWT  36  22  41  24 /  40  10  10  10

&&

.TFX WATCHES/WARNINGS/ADVISORIES...
FREEZING FOG ADVISORY until 11 AM MST this morning Cascade...
Eastern Teton...Judith Basin...Southern Rocky Mountain Front.

FREEZING FOG ADVISORY until 11 AM MST this morning Eastern
Glacier...Eastern Pondera...Northern Rocky Mountain Front...
Toole.

&&

$$

weather.gov/greatfalls
www.twitter.com/NWSGreatFalls
www.facebook.com/NWSGreatFalls





000
FXUS65 KBYZ 171025
AFDBYZ

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BILLINGS MT
325 AM MST WED DEC 17 2014

.SHORT TERM...VALID FOR TDY AND THU...

SHERIDAN WAS REPORTING DENSE FOG THIS MORNING AND AREA WEB CAMS
IN SHERIDAN ALSO SHOWED DENSE FOG. LAST FEW RUNS OF THE HRRR
TARGETED THE SHERIDAN FOOTHILLS WITH DENSE FOG AND DISSIPATED IT
BY 19Z. HAVE ISSUED A DENSE FOG ADVISORY FOR THIS AREA THROUGH
18Z. OTHER AREAS E OF KBIL WILL ALSO HAVE FOG...AND SOME OF IT MAY
BE DENSE...BUT DENSE FOG WILL NOT BE WIDESPREAD ENOUGH TO WARRANT
AN ADVISORY.

TWO SHORTWAVES WERE AFFECTING THE AREA EARLY THIS MORNING. ONE WAS
MOVING INTO SW MT AND THE OTHER WAS OVER W MT PER WATER VAPOR
IMAGERY. THESE WAVES WILL MERGE AND CROSS THE AREA TODAY THROUGH
TONIGHT. THE BEST Q-VECTOR CONVERGENCE WILL OCCUR THIS MORNING
WITH THE WAVES...AND MODELS BROUGHT A DECENT AREA OF MOISTURE
ACROSS THE AREA. DETERMINISTIC MODELS AND SREF ALL SHOWED LIGHT
WIDELY SCATTERED QPF TODAY. SO WENT WITH MAINLY SCATTERED
FLURRIES...WITH CHANCE POPS IN THE WESTERN MOUNTAINS THIS MORNING.
CHANCES FOR PRECIPITATION WILL END TONIGHT. A WARM FRONT WILL PUSH
INTO THE REGION TONIGHT AND USHER IN WARMING CONDITIONS THROUGH
THU. ANOTHER WAVE APPROACHES THU AND MOVES INTO THE AREA THU
NIGHT. PRECIPITATION CHANCES WILL BE CONFINED TO THE MOUNTAINS.

TEMPERATURES TODAY WILL BE HIGHER THAN YESTERDAY/S READINGS AND
WILL BE WARMER YET ON THU. ARTHUR

.LONG TERM...VALID FOR FRI...SAT...SUN...MON...TUE...

MODELS ARE IN DECENT AGREEMENT THROUGH THE EXTENDED PERIOD AS
THEY SHOW AN UNSETTLED PATTERN. MAIN FORECAST ISSUE WILL BE SUNDAY
INTO MONDAY AND AGAIN CHRISTMAS EVE/CHRISTMAS DAY AS THESE
PERIODS SHOW THE LIKELIHOOD OF A STORM SYSTEM IMPACTING THE AREA.
BRIEF RIDGING WILL BE OVER THE FORECAST AREA FRIDAY BEFORE A WEAK
DISTURBANCE MOVES ACROSS THE AREA FRIDAY NIGHT INTO SATURDAY
BRINGING A SLIGHT CHANCE FOR RAIN AND SNOW SHOWERS. AN UNSETTLED
NORTHWEST FLOW ALOFT WILL PREVAIL OVER THE WEEKEND RESULTING IN A
SLIGHT SHOWER CHANCE SATURDAY. LEE-SIDE TROUGHING SETS UP SUNDAY
BEFORE A COLD FRONT MOVES THROUGH MONDAY. TIGHT PRESSURE GRADIENTS
WILL BE ACROSS THE BEARTOOTH/ABSAROKA FOOTHILLS SUNDAY SHIFTING
EAST MONDAY RESULTING IN WINDY PERIODS ACROSS THE AREA.

A CONTINUOUS FLOW OF MOISTURE OFF THE PACIFIC WILL MOVE ACROSS
IDAHO INTO MONTANA SUNDAY INTO MONDAY BRINGING CHANCES FOR SHOWERS
ACROSS THE PLAINS WITH SNOW LIKELY FOR THE MOUNTAINS. THERE WILL
BE A BRIEF BREAK TUESDAY BEFORE THE NEXT STORM SYSTEM IMPACTS OUR
FORECAST AREA WEDNESDAY AND THURSDAY. MODELS ARE IN PRETTY GOOD
AGREEMENT IN CARVING OUT A LARGE TROUGH ACROSS THE NORTHERN
ROCKIES WEDNESDAY AND THURSDAY...AS WELL AS PLACING AN UPPER LOW
IN OUR VICINITY. FORECASTER CONFIDENCE IS HIGH FOR A CHRISTMAS
SNOW EVENT BUT DETAILS SUCH AS SNOW AMOUNTS ARE UNCERTAIN AT THIS
TIME. HOOLEY
&&

.AVIATION...

LOW CEILINGS ALONG WITH AREAS OF DENSE FOG WILL CONTINUE TO POSE
AN AVIATION HAZARD THROUGH THIS MORNING. MVFR TO IFR CONDITIONS
WILL PREVAIL WITH AREAS OF LIFR FROM KSHR TO KBIL THROUGH 18Z. THE
EXCEPTION WILL BE THE KLVM AREA AND ADJACENT FOOTHILLS WHERE VFR
CONDITIONS WILL PREVAIL. THE MOUNTAINS WILL BE OBSCURED AT TIMES
THROUGHOUT THE DAY. HOOLEY


&&

.PRELIMINARY POINT TEMP/POPS...

    TDY THU     FRI     SAT     SUN     MON     TUE
-------------------------------------------------------
BIL 035 023/039 023/038 027/042 026/044 035/047 027/041
    1/M 00/B    00/B    11/B    23/W    33/W    32/W
LVM 040 022/041 024/040 026/043 026/041 036/047 027/043
    2/W 01/N    11/B    21/N    23/W    33/W    33/W
HDN 032 015/037 016/037 020/040 019/041 029/044 023/040
    1/M 10/B    00/B    01/B    12/J    33/W    32/W
MLS 029 017/036 019/037 019/039 022/041 029/043 023/039
    1/M 10/B    00/B    11/B    12/J    23/W    11/B
4BQ 030 016/039 017/040 017/041 020/043 030/045 024/041
    1/M 10/B    00/B    11/B    12/J    23/W    21/B
BHK 024 015/034 018/037 017/039 020/040 027/041 021/037
    1/M 20/B    10/B    01/B    11/B    22/W    11/B
SHR 035 016/038 016/038 019/040 019/041 028/043 022/040
    1/M 00/B    10/B    12/J    12/J    34/W    32/W

&&

.BYZ WATCHES/WARNINGS/ADVISORIES...
MT...NONE.
WY...DENSE FOG ADVISORY IN EFFECT UNTIL 11 AM MST THIS MORNING FOR
      ZONE 99.

&&

$$
WEATHER.GOV/BILLINGS



000
FXUS65 KBYZ 171025
AFDBYZ

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BILLINGS MT
325 AM MST WED DEC 17 2014

.SHORT TERM...VALID FOR TDY AND THU...

SHERIDAN WAS REPORTING DENSE FOG THIS MORNING AND AREA WEB CAMS
IN SHERIDAN ALSO SHOWED DENSE FOG. LAST FEW RUNS OF THE HRRR
TARGETED THE SHERIDAN FOOTHILLS WITH DENSE FOG AND DISSIPATED IT
BY 19Z. HAVE ISSUED A DENSE FOG ADVISORY FOR THIS AREA THROUGH
18Z. OTHER AREAS E OF KBIL WILL ALSO HAVE FOG...AND SOME OF IT MAY
BE DENSE...BUT DENSE FOG WILL NOT BE WIDESPREAD ENOUGH TO WARRANT
AN ADVISORY.

TWO SHORTWAVES WERE AFFECTING THE AREA EARLY THIS MORNING. ONE WAS
MOVING INTO SW MT AND THE OTHER WAS OVER W MT PER WATER VAPOR
IMAGERY. THESE WAVES WILL MERGE AND CROSS THE AREA TODAY THROUGH
TONIGHT. THE BEST Q-VECTOR CONVERGENCE WILL OCCUR THIS MORNING
WITH THE WAVES...AND MODELS BROUGHT A DECENT AREA OF MOISTURE
ACROSS THE AREA. DETERMINISTIC MODELS AND SREF ALL SHOWED LIGHT
WIDELY SCATTERED QPF TODAY. SO WENT WITH MAINLY SCATTERED
FLURRIES...WITH CHANCE POPS IN THE WESTERN MOUNTAINS THIS MORNING.
CHANCES FOR PRECIPITATION WILL END TONIGHT. A WARM FRONT WILL PUSH
INTO THE REGION TONIGHT AND USHER IN WARMING CONDITIONS THROUGH
THU. ANOTHER WAVE APPROACHES THU AND MOVES INTO THE AREA THU
NIGHT. PRECIPITATION CHANCES WILL BE CONFINED TO THE MOUNTAINS.

TEMPERATURES TODAY WILL BE HIGHER THAN YESTERDAY/S READINGS AND
WILL BE WARMER YET ON THU. ARTHUR

.LONG TERM...VALID FOR FRI...SAT...SUN...MON...TUE...

MODELS ARE IN DECENT AGREEMENT THROUGH THE EXTENDED PERIOD AS
THEY SHOW AN UNSETTLED PATTERN. MAIN FORECAST ISSUE WILL BE SUNDAY
INTO MONDAY AND AGAIN CHRISTMAS EVE/CHRISTMAS DAY AS THESE
PERIODS SHOW THE LIKELIHOOD OF A STORM SYSTEM IMPACTING THE AREA.
BRIEF RIDGING WILL BE OVER THE FORECAST AREA FRIDAY BEFORE A WEAK
DISTURBANCE MOVES ACROSS THE AREA FRIDAY NIGHT INTO SATURDAY
BRINGING A SLIGHT CHANCE FOR RAIN AND SNOW SHOWERS. AN UNSETTLED
NORTHWEST FLOW ALOFT WILL PREVAIL OVER THE WEEKEND RESULTING IN A
SLIGHT SHOWER CHANCE SATURDAY. LEE-SIDE TROUGHING SETS UP SUNDAY
BEFORE A COLD FRONT MOVES THROUGH MONDAY. TIGHT PRESSURE GRADIENTS
WILL BE ACROSS THE BEARTOOTH/ABSAROKA FOOTHILLS SUNDAY SHIFTING
EAST MONDAY RESULTING IN WINDY PERIODS ACROSS THE AREA.

A CONTINUOUS FLOW OF MOISTURE OFF THE PACIFIC WILL MOVE ACROSS
IDAHO INTO MONTANA SUNDAY INTO MONDAY BRINGING CHANCES FOR SHOWERS
ACROSS THE PLAINS WITH SNOW LIKELY FOR THE MOUNTAINS. THERE WILL
BE A BRIEF BREAK TUESDAY BEFORE THE NEXT STORM SYSTEM IMPACTS OUR
FORECAST AREA WEDNESDAY AND THURSDAY. MODELS ARE IN PRETTY GOOD
AGREEMENT IN CARVING OUT A LARGE TROUGH ACROSS THE NORTHERN
ROCKIES WEDNESDAY AND THURSDAY...AS WELL AS PLACING AN UPPER LOW
IN OUR VICINITY. FORECASTER CONFIDENCE IS HIGH FOR A CHRISTMAS
SNOW EVENT BUT DETAILS SUCH AS SNOW AMOUNTS ARE UNCERTAIN AT THIS
TIME. HOOLEY
&&

.AVIATION...

LOW CEILINGS ALONG WITH AREAS OF DENSE FOG WILL CONTINUE TO POSE
AN AVIATION HAZARD THROUGH THIS MORNING. MVFR TO IFR CONDITIONS
WILL PREVAIL WITH AREAS OF LIFR FROM KSHR TO KBIL THROUGH 18Z. THE
EXCEPTION WILL BE THE KLVM AREA AND ADJACENT FOOTHILLS WHERE VFR
CONDITIONS WILL PREVAIL. THE MOUNTAINS WILL BE OBSCURED AT TIMES
THROUGHOUT THE DAY. HOOLEY


&&

.PRELIMINARY POINT TEMP/POPS...

    TDY THU     FRI     SAT     SUN     MON     TUE
-------------------------------------------------------
BIL 035 023/039 023/038 027/042 026/044 035/047 027/041
    1/M 00/B    00/B    11/B    23/W    33/W    32/W
LVM 040 022/041 024/040 026/043 026/041 036/047 027/043
    2/W 01/N    11/B    21/N    23/W    33/W    33/W
HDN 032 015/037 016/037 020/040 019/041 029/044 023/040
    1/M 10/B    00/B    01/B    12/J    33/W    32/W
MLS 029 017/036 019/037 019/039 022/041 029/043 023/039
    1/M 10/B    00/B    11/B    12/J    23/W    11/B
4BQ 030 016/039 017/040 017/041 020/043 030/045 024/041
    1/M 10/B    00/B    11/B    12/J    23/W    21/B
BHK 024 015/034 018/037 017/039 020/040 027/041 021/037
    1/M 20/B    10/B    01/B    11/B    22/W    11/B
SHR 035 016/038 016/038 019/040 019/041 028/043 022/040
    1/M 00/B    10/B    12/J    12/J    34/W    32/W

&&

.BYZ WATCHES/WARNINGS/ADVISORIES...
MT...NONE.
WY...DENSE FOG ADVISORY IN EFFECT UNTIL 11 AM MST THIS MORNING FOR
      ZONE 99.

&&

$$
WEATHER.GOV/BILLINGS




000
FXUS65 KGGW 171024
AFDGGW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GLASGOW MT
324 AM MST WED DEC 17 2014

.SHORT TERM...FOR NORTHEAST MONTANA...TODAY THROUGH FRIDAY...
LOW STRATUS DECK REMAINS IN PLACE ACROSS EASTERN MONTANA. CEILINGS
ARE LOWERING...INCREASING THE POTENTIAL FOR FOG OVER THE HIGHER
TERRAIN AREAS. SHORTWAVE LIFTING OUT OF IDAHO EXPECTED TO BRING
INCREASED MOISTURE INTO THE MIDLEVEL...ALLOWING FOR A LITTLE MORE
MIXING AND INSTABILITY ALOFT. THIS COULD HELP CLEAR OUT THE LOWER
CLOUDS AND COULD PRODUCE A LITTLE LIGHT PRECIPITATION. MOSTLY
EXPECT PRECIP TO OCCUR AS SNOW BUT COULD SEE A LITTLE FREEZING
RAIN AS THE MOISTURE DEEPENS.

WINDS GO AROUND TO WEST BEHIND THE SHORTWAVE ON THURSDAY WHICH
SHOULD ALSO AID IN PUSHING THE LOW CLOUD OUT OF THE REGION.
AIRMASS ALOFT WARMS SOME BUT LOW LEVEL INVERSION SHOULD PERSIST
ESPECIALLY OVER THE RIVER VALLEYS OF NORTHEAST MONTANA. BY FRIDAY
UPPER RIDGE BUILDS INTO THE NORTHERN ROCKIES STARTING A CHINOOK
ALONG THE FRONT RANGE. EBERT


.LONG TERM...FRIDAY NIGHT THROUGH WEDNESDAY...

THE GENERAL SYNOPTIC FLOW REGIME FOR THE EXTENDED FORECAST PERIOD
WILL BE FROM THE WEST AND NORTHWEST WITH A FEW EMBEDDED SMALL-
SCALE DISTURBANCES EARLY IN THE PERIOD...FOLLOWED BY A LARGER-
SCALE STORM SYSTEM OVER THE REGION TOWARD CHRISTMAS EVE.

FIRST...EARLY SUNDAY MORNING...A SMALL DISTURBANCE EMERGES OVER
THE CANADIAN ROCKIES AND GAINS ENOUGH FORCING AND MOISTURE TO
SQUEEZE OUT SOME LIGHT PRECIPITATION. BASICALLY WENT WITH A MODEL
BLEND HERE...SLIGHTLY FAVORING THE EC FOR ITS RUN TO RUN
CONSISTENCY. NOT EXPECTING MUCH...MAYBE A HALF INCH OF SNOW NORTH
OF THE MISSOURI RIVER AND SOME LIGHT RAIN SOUTH OF THE MISSOURI
RIVER.

MONDAY NIGHT THROUGH WEDNESDAY NIGHT...A STRONGER AND MORE-
ESTABLISHED NORTHWESTERLY FLOW ALOFT SEEMS TO TAKE ROOT OVER THE
REGION AND SETS UP SOME HIGHER ELEVATION AREAS OF CENTRAL MONTANA
WITH OVER-RUNNING AND ACCUMULATING PRECIPITATION. THIS WILL LIKELY
REMAIN CONFINED TO THE NE AND SW CORNERS OF OUR CWA. MODELS
INDICATE THAT THIS PRECIPITATION TREND WILL LATER THE BECOME
ENHANCED BY A COLD AIR MASS...LARGER TROUGH...AND STRONGER STORM
SYSTEM POSSIBLY BY CHRISTMAS TIME. TRIED TO REFLECT THIS THINKING
WITH THE FORECAST GRIDS. BMICKELSON


&&

.AVIATION...

PERSISTENT AND PESKY LOW-LEVEL CEILINGS WILL CONTINUE TO IMPACT
ALL TAF SITES WITH IFR TO NEAR-IFR CONDITIONS THROUGH MOST OF THIS
TAF CYCLE. PATCHY FREEZING MIST OR FOG IS ALSO POSSIBLE WHICH
COULD LEAD TO RESTRICTED VISIBILITY AT TIMES. CONFIDENCE ON FOG
HOWEVER IS CURRENTLY LOW. EAST-SOUTHEASTERLY WINDS WILL PERSIST
AROUND 8 TO 12 KTS. MALIAWCO/MICKELSON


&&

.GLASGOW WATCHES/WARNINGS/ADVISORIES...NONE.

&&

$$

WEATHER.GOV/GLASGOW






000
FXUS65 KGGW 171024
AFDGGW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GLASGOW MT
324 AM MST WED DEC 17 2014

.SHORT TERM...FOR NORTHEAST MONTANA...TODAY THROUGH FRIDAY...
LOW STRATUS DECK REMAINS IN PLACE ACROSS EASTERN MONTANA. CEILINGS
ARE LOWERING...INCREASING THE POTENTIAL FOR FOG OVER THE HIGHER
TERRAIN AREAS. SHORTWAVE LIFTING OUT OF IDAHO EXPECTED TO BRING
INCREASED MOISTURE INTO THE MIDLEVEL...ALLOWING FOR A LITTLE MORE
MIXING AND INSTABILITY ALOFT. THIS COULD HELP CLEAR OUT THE LOWER
CLOUDS AND COULD PRODUCE A LITTLE LIGHT PRECIPITATION. MOSTLY
EXPECT PRECIP TO OCCUR AS SNOW BUT COULD SEE A LITTLE FREEZING
RAIN AS THE MOISTURE DEEPENS.

WINDS GO AROUND TO WEST BEHIND THE SHORTWAVE ON THURSDAY WHICH
SHOULD ALSO AID IN PUSHING THE LOW CLOUD OUT OF THE REGION.
AIRMASS ALOFT WARMS SOME BUT LOW LEVEL INVERSION SHOULD PERSIST
ESPECIALLY OVER THE RIVER VALLEYS OF NORTHEAST MONTANA. BY FRIDAY
UPPER RIDGE BUILDS INTO THE NORTHERN ROCKIES STARTING A CHINOOK
ALONG THE FRONT RANGE. EBERT


.LONG TERM...FRIDAY NIGHT THROUGH WEDNESDAY...

THE GENERAL SYNOPTIC FLOW REGIME FOR THE EXTENDED FORECAST PERIOD
WILL BE FROM THE WEST AND NORTHWEST WITH A FEW EMBEDDED SMALL-
SCALE DISTURBANCES EARLY IN THE PERIOD...FOLLOWED BY A LARGER-
SCALE STORM SYSTEM OVER THE REGION TOWARD CHRISTMAS EVE.

FIRST...EARLY SUNDAY MORNING...A SMALL DISTURBANCE EMERGES OVER
THE CANADIAN ROCKIES AND GAINS ENOUGH FORCING AND MOISTURE TO
SQUEEZE OUT SOME LIGHT PRECIPITATION. BASICALLY WENT WITH A MODEL
BLEND HERE...SLIGHTLY FAVORING THE EC FOR ITS RUN TO RUN
CONSISTENCY. NOT EXPECTING MUCH...MAYBE A HALF INCH OF SNOW NORTH
OF THE MISSOURI RIVER AND SOME LIGHT RAIN SOUTH OF THE MISSOURI
RIVER.

MONDAY NIGHT THROUGH WEDNESDAY NIGHT...A STRONGER AND MORE-
ESTABLISHED NORTHWESTERLY FLOW ALOFT SEEMS TO TAKE ROOT OVER THE
REGION AND SETS UP SOME HIGHER ELEVATION AREAS OF CENTRAL MONTANA
WITH OVER-RUNNING AND ACCUMULATING PRECIPITATION. THIS WILL LIKELY
REMAIN CONFINED TO THE NE AND SW CORNERS OF OUR CWA. MODELS
INDICATE THAT THIS PRECIPITATION TREND WILL LATER THE BECOME
ENHANCED BY A COLD AIR MASS...LARGER TROUGH...AND STRONGER STORM
SYSTEM POSSIBLY BY CHRISTMAS TIME. TRIED TO REFLECT THIS THINKING
WITH THE FORECAST GRIDS. BMICKELSON


&&

.AVIATION...

PERSISTENT AND PESKY LOW-LEVEL CEILINGS WILL CONTINUE TO IMPACT
ALL TAF SITES WITH IFR TO NEAR-IFR CONDITIONS THROUGH MOST OF THIS
TAF CYCLE. PATCHY FREEZING MIST OR FOG IS ALSO POSSIBLE WHICH
COULD LEAD TO RESTRICTED VISIBILITY AT TIMES. CONFIDENCE ON FOG
HOWEVER IS CURRENTLY LOW. EAST-SOUTHEASTERLY WINDS WILL PERSIST
AROUND 8 TO 12 KTS. MALIAWCO/MICKELSON


&&

.GLASGOW WATCHES/WARNINGS/ADVISORIES...NONE.

&&

$$

WEATHER.GOV/GLASGOW






000
FXUS65 KGGW 171024
AFDGGW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GLASGOW MT
324 AM MST WED DEC 17 2014

.SHORT TERM...FOR NORTHEAST MONTANA...TODAY THROUGH FRIDAY...
LOW STRATUS DECK REMAINS IN PLACE ACROSS EASTERN MONTANA. CEILINGS
ARE LOWERING...INCREASING THE POTENTIAL FOR FOG OVER THE HIGHER
TERRAIN AREAS. SHORTWAVE LIFTING OUT OF IDAHO EXPECTED TO BRING
INCREASED MOISTURE INTO THE MIDLEVEL...ALLOWING FOR A LITTLE MORE
MIXING AND INSTABILITY ALOFT. THIS COULD HELP CLEAR OUT THE LOWER
CLOUDS AND COULD PRODUCE A LITTLE LIGHT PRECIPITATION. MOSTLY
EXPECT PRECIP TO OCCUR AS SNOW BUT COULD SEE A LITTLE FREEZING
RAIN AS THE MOISTURE DEEPENS.

WINDS GO AROUND TO WEST BEHIND THE SHORTWAVE ON THURSDAY WHICH
SHOULD ALSO AID IN PUSHING THE LOW CLOUD OUT OF THE REGION.
AIRMASS ALOFT WARMS SOME BUT LOW LEVEL INVERSION SHOULD PERSIST
ESPECIALLY OVER THE RIVER VALLEYS OF NORTHEAST MONTANA. BY FRIDAY
UPPER RIDGE BUILDS INTO THE NORTHERN ROCKIES STARTING A CHINOOK
ALONG THE FRONT RANGE. EBERT


.LONG TERM...FRIDAY NIGHT THROUGH WEDNESDAY...

THE GENERAL SYNOPTIC FLOW REGIME FOR THE EXTENDED FORECAST PERIOD
WILL BE FROM THE WEST AND NORTHWEST WITH A FEW EMBEDDED SMALL-
SCALE DISTURBANCES EARLY IN THE PERIOD...FOLLOWED BY A LARGER-
SCALE STORM SYSTEM OVER THE REGION TOWARD CHRISTMAS EVE.

FIRST...EARLY SUNDAY MORNING...A SMALL DISTURBANCE EMERGES OVER
THE CANADIAN ROCKIES AND GAINS ENOUGH FORCING AND MOISTURE TO
SQUEEZE OUT SOME LIGHT PRECIPITATION. BASICALLY WENT WITH A MODEL
BLEND HERE...SLIGHTLY FAVORING THE EC FOR ITS RUN TO RUN
CONSISTENCY. NOT EXPECTING MUCH...MAYBE A HALF INCH OF SNOW NORTH
OF THE MISSOURI RIVER AND SOME LIGHT RAIN SOUTH OF THE MISSOURI
RIVER.

MONDAY NIGHT THROUGH WEDNESDAY NIGHT...A STRONGER AND MORE-
ESTABLISHED NORTHWESTERLY FLOW ALOFT SEEMS TO TAKE ROOT OVER THE
REGION AND SETS UP SOME HIGHER ELEVATION AREAS OF CENTRAL MONTANA
WITH OVER-RUNNING AND ACCUMULATING PRECIPITATION. THIS WILL LIKELY
REMAIN CONFINED TO THE NE AND SW CORNERS OF OUR CWA. MODELS
INDICATE THAT THIS PRECIPITATION TREND WILL LATER THE BECOME
ENHANCED BY A COLD AIR MASS...LARGER TROUGH...AND STRONGER STORM
SYSTEM POSSIBLY BY CHRISTMAS TIME. TRIED TO REFLECT THIS THINKING
WITH THE FORECAST GRIDS. BMICKELSON


&&

.AVIATION...

PERSISTENT AND PESKY LOW-LEVEL CEILINGS WILL CONTINUE TO IMPACT
ALL TAF SITES WITH IFR TO NEAR-IFR CONDITIONS THROUGH MOST OF THIS
TAF CYCLE. PATCHY FREEZING MIST OR FOG IS ALSO POSSIBLE WHICH
COULD LEAD TO RESTRICTED VISIBILITY AT TIMES. CONFIDENCE ON FOG
HOWEVER IS CURRENTLY LOW. EAST-SOUTHEASTERLY WINDS WILL PERSIST
AROUND 8 TO 12 KTS. MALIAWCO/MICKELSON


&&

.GLASGOW WATCHES/WARNINGS/ADVISORIES...NONE.

&&

$$

WEATHER.GOV/GLASGOW






000
FXUS65 KGGW 171024
AFDGGW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GLASGOW MT
324 AM MST WED DEC 17 2014

.SHORT TERM...FOR NORTHEAST MONTANA...TODAY THROUGH FRIDAY...
LOW STRATUS DECK REMAINS IN PLACE ACROSS EASTERN MONTANA. CEILINGS
ARE LOWERING...INCREASING THE POTENTIAL FOR FOG OVER THE HIGHER
TERRAIN AREAS. SHORTWAVE LIFTING OUT OF IDAHO EXPECTED TO BRING
INCREASED MOISTURE INTO THE MIDLEVEL...ALLOWING FOR A LITTLE MORE
MIXING AND INSTABILITY ALOFT. THIS COULD HELP CLEAR OUT THE LOWER
CLOUDS AND COULD PRODUCE A LITTLE LIGHT PRECIPITATION. MOSTLY
EXPECT PRECIP TO OCCUR AS SNOW BUT COULD SEE A LITTLE FREEZING
RAIN AS THE MOISTURE DEEPENS.

WINDS GO AROUND TO WEST BEHIND THE SHORTWAVE ON THURSDAY WHICH
SHOULD ALSO AID IN PUSHING THE LOW CLOUD OUT OF THE REGION.
AIRMASS ALOFT WARMS SOME BUT LOW LEVEL INVERSION SHOULD PERSIST
ESPECIALLY OVER THE RIVER VALLEYS OF NORTHEAST MONTANA. BY FRIDAY
UPPER RIDGE BUILDS INTO THE NORTHERN ROCKIES STARTING A CHINOOK
ALONG THE FRONT RANGE. EBERT


.LONG TERM...FRIDAY NIGHT THROUGH WEDNESDAY...

THE GENERAL SYNOPTIC FLOW REGIME FOR THE EXTENDED FORECAST PERIOD
WILL BE FROM THE WEST AND NORTHWEST WITH A FEW EMBEDDED SMALL-
SCALE DISTURBANCES EARLY IN THE PERIOD...FOLLOWED BY A LARGER-
SCALE STORM SYSTEM OVER THE REGION TOWARD CHRISTMAS EVE.

FIRST...EARLY SUNDAY MORNING...A SMALL DISTURBANCE EMERGES OVER
THE CANADIAN ROCKIES AND GAINS ENOUGH FORCING AND MOISTURE TO
SQUEEZE OUT SOME LIGHT PRECIPITATION. BASICALLY WENT WITH A MODEL
BLEND HERE...SLIGHTLY FAVORING THE EC FOR ITS RUN TO RUN
CONSISTENCY. NOT EXPECTING MUCH...MAYBE A HALF INCH OF SNOW NORTH
OF THE MISSOURI RIVER AND SOME LIGHT RAIN SOUTH OF THE MISSOURI
RIVER.

MONDAY NIGHT THROUGH WEDNESDAY NIGHT...A STRONGER AND MORE-
ESTABLISHED NORTHWESTERLY FLOW ALOFT SEEMS TO TAKE ROOT OVER THE
REGION AND SETS UP SOME HIGHER ELEVATION AREAS OF CENTRAL MONTANA
WITH OVER-RUNNING AND ACCUMULATING PRECIPITATION. THIS WILL LIKELY
REMAIN CONFINED TO THE NE AND SW CORNERS OF OUR CWA. MODELS
INDICATE THAT THIS PRECIPITATION TREND WILL LATER THE BECOME
ENHANCED BY A COLD AIR MASS...LARGER TROUGH...AND STRONGER STORM
SYSTEM POSSIBLY BY CHRISTMAS TIME. TRIED TO REFLECT THIS THINKING
WITH THE FORECAST GRIDS. BMICKELSON


&&

.AVIATION...

PERSISTENT AND PESKY LOW-LEVEL CEILINGS WILL CONTINUE TO IMPACT
ALL TAF SITES WITH IFR TO NEAR-IFR CONDITIONS THROUGH MOST OF THIS
TAF CYCLE. PATCHY FREEZING MIST OR FOG IS ALSO POSSIBLE WHICH
COULD LEAD TO RESTRICTED VISIBILITY AT TIMES. CONFIDENCE ON FOG
HOWEVER IS CURRENTLY LOW. EAST-SOUTHEASTERLY WINDS WILL PERSIST
AROUND 8 TO 12 KTS. MALIAWCO/MICKELSON


&&

.GLASGOW WATCHES/WARNINGS/ADVISORIES...NONE.

&&

$$

WEATHER.GOV/GLASGOW






000
FXUS65 KTFX 170545
AFDTFX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREAT FALLS MT
1045 PM MST Tue Dec 16 2014

Aviation section updated

.UPDATE...
A band of light snow continues to push northward from Southwest
Montana into Central Montana. However...as this band pushes
northward...it is weakening a bit. Thus Bozeman...Helena...Great
Falls and Lewistown look to be on the edges of this system and
these locations will generally see just some minor snow
accumulations. The heavier swath of around an inch of snowfall
should move through the Dillon...Whitehall...Townsend and Kings
Hill region. I have precip extending northward into the Havre area
on Wednesday morning...but any snowfall in this region will be
quite light...generally less than a quarter of an inch. In terms
of fog...I have left the highlights alone...as patchy dense fog
continues to affect portions of the region. The fog might not be
as widespread in the Great Falls/Stanford areas right now...but
just enough fog around to keep the highlight going for now. The Cut
Bank area continues to have visibility around 1/4SM so the advisory
looks good in this region. Overnight lows are on track...with just
a few minor adjustments towards current readings. Brusda

&&

.AVIATION...
UPDATED 0545Z.
Light snow continues to push northward from Southwest MT into
Central MT. Expect visibilities to generally be 2SM in areas of snow
along with mountains obscured. There is only a small chance the snow
will make into the Great Falls and Havre areas. Areas of dense fog
will continue to affect the Cut Bank area until Wednesday morning.
Expect VFR conditions to develop over much of the region on
Wednesday afternoon...as southwesterly winds start to develop. Brusda

&&

.PREV DISCUSSION...
/ISSUED 450 PM MST Tue Dec 16 2014/
Tonight through Thursday...Relatively quiet conditions over
central and north central Montana during the period. Areas of
freezing fog continue to cover portions of north central Montana
this afternoon...and those areas that did burn off will likely
see the fog redevelop late this afternoon or this evening. Have
extended the Freezing Fog Advisory for most of north central
Montana until 11 a.m. Wednesday.

Upper air pattern shows a high pressure ridge over the Rocky
Mountain states with a low pressure trough over the west coast.
Idiosyncrasies in the pattern are resulting in a split flow aloft
over southwest and central Montana...and small weather systems
embedded in the flow, and being steered into Montana, are being
sheared apart and weakened. Best chance for snow from these
systems will be over the southwest Montana mountains. Probabilities
decrease to only slight chances as the system moves to the
northeast over central Montana. As the high pressure ridge shifts
east and the trough begins to move inland, another system will
approach the area during the day Thursday. This again brings slight
chances for snow mainly over the west and southwest mountains.
Temperatures will remain near seasonal averages for this time of
year.

Thursday Night through Tuesday...A weak upper level ridge of high
pressure will keep the forecast area mostly dry Thursday night and
Friday. A shortwave trough will then move into the area Friday
night into Saturday, bringing an increased chance of mountain
snow. However, breezy westerly downslope winds will keep the
plains dry. The weather pattern will change somewhat beginning on
Sunday. An upper level ridge of high pressure will strengthen off
the California coast and an upper level trough of low pressure
will deepen from Hudson Bay into the Great Lakes. This will put
Montana under the influence of a strong northwesterly flow aloft.
The strongest winds aloft (60 to 70 kt at 700 mb) will occur
Sunday into Monday with the passage of a disturbance embedded in
the flow. This set- up will bring gusty westerly downslope winds
to much of the area, but especially over the plains of north
central Montana. In fact, some areas along the Rocky Mountain
Front could approach High Wind criteria (40 mph sustained/58 mph
gusts). Confidence is increasing that High Wind highlights may be
needed for this event. There is also significant moisture with
this disturbance, so have increased the chance for precipitation
out onto the plains. Although the winds will decrease somewhat
after the passage of the disturbance, the northwesterly flow aloft
will remain fairly moist, so have kept the chance for
precipitation above climatological normals across the area into
Tuesday. The breezy winds throughout the period will keep
temperatures around 10 degrees above normal. The warmest day of
the period appears to be Monday, when most lower elevation
locations should get well into the 40s. Coulston

&&

.PRELIMINARY POINT TEMPS/POPS...
GTF  17  37  25  37 /  50  30  10  10
CTB  18  34  22  36 /  10  10  10  10
HLN  23  31  18  33 /  80  20  10  20
BZN  18  31  14  30 /  90  20  10  20
WEY  21  31  17  28 / 100  40  20  30
DLN  22  33  17  33 / 100  20  10  20
HVR  17  31  19  35 /   0  30  20  10
LWT  14  38  22  39 /  60  40  10  10

&&

.TFX WATCHES/WARNINGS/ADVISORIES...
FREEZING FOG ADVISORY until 11 AM MST Wednesday Cascade...
Eastern Teton...Judith Basin...Southern Rocky Mountain Front.

FREEZING FOG ADVISORY until 11 AM MST Wednesday Eastern
Glacier...Eastern Pondera...Northern Rocky Mountain Front...
Toole.

&&

$$

weather.gov/greatfalls
www.twitter.com/NWSGreatFalls
www.facebook.com/NWSGreatFalls





000
FXUS65 KTFX 170545
AFDTFX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREAT FALLS MT
1045 PM MST Tue Dec 16 2014

Aviation section updated

.UPDATE...
A band of light snow continues to push northward from Southwest
Montana into Central Montana. However...as this band pushes
northward...it is weakening a bit. Thus Bozeman...Helena...Great
Falls and Lewistown look to be on the edges of this system and
these locations will generally see just some minor snow
accumulations. The heavier swath of around an inch of snowfall
should move through the Dillon...Whitehall...Townsend and Kings
Hill region. I have precip extending northward into the Havre area
on Wednesday morning...but any snowfall in this region will be
quite light...generally less than a quarter of an inch. In terms
of fog...I have left the highlights alone...as patchy dense fog
continues to affect portions of the region. The fog might not be
as widespread in the Great Falls/Stanford areas right now...but
just enough fog around to keep the highlight going for now. The Cut
Bank area continues to have visibility around 1/4SM so the advisory
looks good in this region. Overnight lows are on track...with just
a few minor adjustments towards current readings. Brusda

&&

.AVIATION...
UPDATED 0545Z.
Light snow continues to push northward from Southwest MT into
Central MT. Expect visibilities to generally be 2SM in areas of snow
along with mountains obscured. There is only a small chance the snow
will make into the Great Falls and Havre areas. Areas of dense fog
will continue to affect the Cut Bank area until Wednesday morning.
Expect VFR conditions to develop over much of the region on
Wednesday afternoon...as southwesterly winds start to develop. Brusda

&&

.PREV DISCUSSION...
/ISSUED 450 PM MST Tue Dec 16 2014/
Tonight through Thursday...Relatively quiet conditions over
central and north central Montana during the period. Areas of
freezing fog continue to cover portions of north central Montana
this afternoon...and those areas that did burn off will likely
see the fog redevelop late this afternoon or this evening. Have
extended the Freezing Fog Advisory for most of north central
Montana until 11 a.m. Wednesday.

Upper air pattern shows a high pressure ridge over the Rocky
Mountain states with a low pressure trough over the west coast.
Idiosyncrasies in the pattern are resulting in a split flow aloft
over southwest and central Montana...and small weather systems
embedded in the flow, and being steered into Montana, are being
sheared apart and weakened. Best chance for snow from these
systems will be over the southwest Montana mountains. Probabilities
decrease to only slight chances as the system moves to the
northeast over central Montana. As the high pressure ridge shifts
east and the trough begins to move inland, another system will
approach the area during the day Thursday. This again brings slight
chances for snow mainly over the west and southwest mountains.
Temperatures will remain near seasonal averages for this time of
year.

Thursday Night through Tuesday...A weak upper level ridge of high
pressure will keep the forecast area mostly dry Thursday night and
Friday. A shortwave trough will then move into the area Friday
night into Saturday, bringing an increased chance of mountain
snow. However, breezy westerly downslope winds will keep the
plains dry. The weather pattern will change somewhat beginning on
Sunday. An upper level ridge of high pressure will strengthen off
the California coast and an upper level trough of low pressure
will deepen from Hudson Bay into the Great Lakes. This will put
Montana under the influence of a strong northwesterly flow aloft.
The strongest winds aloft (60 to 70 kt at 700 mb) will occur
Sunday into Monday with the passage of a disturbance embedded in
the flow. This set- up will bring gusty westerly downslope winds
to much of the area, but especially over the plains of north
central Montana. In fact, some areas along the Rocky Mountain
Front could approach High Wind criteria (40 mph sustained/58 mph
gusts). Confidence is increasing that High Wind highlights may be
needed for this event. There is also significant moisture with
this disturbance, so have increased the chance for precipitation
out onto the plains. Although the winds will decrease somewhat
after the passage of the disturbance, the northwesterly flow aloft
will remain fairly moist, so have kept the chance for
precipitation above climatological normals across the area into
Tuesday. The breezy winds throughout the period will keep
temperatures around 10 degrees above normal. The warmest day of
the period appears to be Monday, when most lower elevation
locations should get well into the 40s. Coulston

&&

.PRELIMINARY POINT TEMPS/POPS...
GTF  17  37  25  37 /  50  30  10  10
CTB  18  34  22  36 /  10  10  10  10
HLN  23  31  18  33 /  80  20  10  20
BZN  18  31  14  30 /  90  20  10  20
WEY  21  31  17  28 / 100  40  20  30
DLN  22  33  17  33 / 100  20  10  20
HVR  17  31  19  35 /   0  30  20  10
LWT  14  38  22  39 /  60  40  10  10

&&

.TFX WATCHES/WARNINGS/ADVISORIES...
FREEZING FOG ADVISORY until 11 AM MST Wednesday Cascade...
Eastern Teton...Judith Basin...Southern Rocky Mountain Front.

FREEZING FOG ADVISORY until 11 AM MST Wednesday Eastern
Glacier...Eastern Pondera...Northern Rocky Mountain Front...
Toole.

&&

$$

weather.gov/greatfalls
www.twitter.com/NWSGreatFalls
www.facebook.com/NWSGreatFalls




000
FXUS65 KTFX 170415
AFDTFX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREAT FALLS MT
915 PM MST Tue Dec 16 2014

.UPDATE...
A band of light snow continues to push northward from Southwest
Montana into Central Montana. However...as this band pushes
northward...it is weakening a bit. Thus Bozeman...Helena...Great
Falls and Lewistown look to be on the edges of this system and
these locations will generally see just some minor snow
accumulations. The heavier swath of around an inch of snowfall
should move through the Dillon...Whitehall...Townsend and Kings
Hill region. I have precip extending northward into the Havre area
on Wednesday morning...but any snowfall in this region will be
quite light...generally less than a quarter of an inch. In terms
of fog...I have left the highlights alone...as patchy dense fog
continues to affect portions of the region. The fog might not be
as widespread in the Great Falls/Stanford areas right now...but
just enough fog around to keep the highlight going for now. The Cut
Bank area continues to have visibility around 1/4SM so the advisory
looks good in this region. Overnight lows are on track...with just
a few minor adjustments towards current readings. Brusda

&&

.AVIATION...
UPDATED 2350Z.
Light snow continues to push northward into Southwest MT. Expect
visibilities to generally be 1SM in areas of snow along with
mountains obscured. The snow will spread into the Helena/Bozeman
areas this evening...and then into the Great Falls/Lewistown areas
over night. The snow should move into the Havre area on Wednesday
morning. Areas of dense fog will continue to affect the Cut Bank
area until Wednesday morning. Brusda

&&

.PREV DISCUSSION...
/ISSUED 450 PM MST Tue Dec 16 2014/
Tonight through Thursday...Relatively quiet conditions over
central and north central Montana during the period. Areas of
freezing fog continue to cover portions of north central Montana
this afternoon...and those areas that did burn off will likely
see the fog redevelop late this afternoon or this evening. Have
extended the Freezing Fog Advisory for most of north central
Montana until 11 a.m. Wednesday.

Upper air pattern shows a high pressure ridge over the Rocky
Mountain states with a low pressure trough over the west coast.
Idiosyncrasies in the pattern are resulting in a split flow aloft
over southwest and central Montana...and small weather systems
embedded in the flow, and being steered into Montana, are being
sheared apart and weakened. Best chance for snow from these
systems will be over the southwest Montana mountains. Probabilities
decrease to only slight chances as the system moves to the
northeast over central Montana. As the high pressure ridge shifts
east and the trough begins to move inland, another system will
approach the area during the day Thursday. This again brings slight
chances for snow mainly over the west and southwest mountains.
Temperatures will remain near seasonal averages for this time of
year.

Thursday Night through Tuesday...A weak upper level ridge of high
pressure will keep the forecast area mostly dry Thursday night and
Friday. A shortwave trough will then move into the area Friday
night into Saturday, bringing an increased chance of mountain
snow. However, breezy westerly downslope winds will keep the
plains dry. The weather pattern will change somewhat beginning on
Sunday. An upper level ridge of high pressure will strengthen off
the California coast and an upper level trough of low pressure
will deepen from Hudson Bay into the Great Lakes. This will put
Montana under the influence of a strong northwesterly flow aloft.
The strongest winds aloft (60 to 70 kt at 700 mb) will occur
Sunday into Monday with the passage of a disturbance embedded in
the flow. This set- up will bring gusty westerly downslope winds
to much of the area, but especially over the plains of north
central Montana. In fact, some areas along the Rocky Mountain
Front could approach High Wind criteria (40 mph sustained/58 mph
gusts). Confidence is increasing that High Wind highlights may be
needed for this event. There is also significant moisture with
this disturbance, so have increased the chance for precipitation
out onto the plains. Although the winds will decrease somewhat
after the passage of the disturbance, the northwesterly flow aloft
will remain fairly moist, so have kept the chance for
precipitation above climatological normals across the area into
Tuesday. The breezy winds throughout the period will keep
temperatures around 10 degrees above normal. The warmest day of
the period appears to be Monday, when most lower elevation
locations should get well into the 40s. Coulston

&&

.PRELIMINARY POINT TEMPS/POPS...
GTF  17  37  25  37 /  50  30  10  10
CTB  18  34  22  36 /  10  10  10  10
HLN  23  31  18  33 /  80  20  10  20
BZN  18  31  14  30 /  90  20  10  20
WEY  21  31  17  28 / 100  40  20  30
DLN  22  33  17  33 / 100  20  10  20
HVR  17  31  19  35 /   0  30  20  10
LWT  14  38  22  39 /  60  40  10  10

&&

.TFX WATCHES/WARNINGS/ADVISORIES...
FREEZING FOG ADVISORY until 11 AM MST Wednesday Cascade...
Eastern Teton...Judith Basin...Southern Rocky Mountain Front.

FREEZING FOG ADVISORY until 11 AM MST Wednesday Eastern
Glacier...Eastern Pondera...Northern Rocky Mountain Front...
Toole.

&&

$$

weather.gov/greatfalls
www.twitter.com/NWSGreatFalls
www.facebook.com/NWSGreatFalls




000
FXUS65 KTFX 170415
AFDTFX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREAT FALLS MT
915 PM MST Tue Dec 16 2014

.UPDATE...
A band of light snow continues to push northward from Southwest
Montana into Central Montana. However...as this band pushes
northward...it is weakening a bit. Thus Bozeman...Helena...Great
Falls and Lewistown look to be on the edges of this system and
these locations will generally see just some minor snow
accumulations. The heavier swath of around an inch of snowfall
should move through the Dillon...Whitehall...Townsend and Kings
Hill region. I have precip extending northward into the Havre area
on Wednesday morning...but any snowfall in this region will be
quite light...generally less than a quarter of an inch. In terms
of fog...I have left the highlights alone...as patchy dense fog
continues to affect portions of the region. The fog might not be
as widespread in the Great Falls/Stanford areas right now...but
just enough fog around to keep the highlight going for now. The Cut
Bank area continues to have visibility around 1/4SM so the advisory
looks good in this region. Overnight lows are on track...with just
a few minor adjustments towards current readings. Brusda

&&

.AVIATION...
UPDATED 2350Z.
Light snow continues to push northward into Southwest MT. Expect
visibilities to generally be 1SM in areas of snow along with
mountains obscured. The snow will spread into the Helena/Bozeman
areas this evening...and then into the Great Falls/Lewistown areas
over night. The snow should move into the Havre area on Wednesday
morning. Areas of dense fog will continue to affect the Cut Bank
area until Wednesday morning. Brusda

&&

.PREV DISCUSSION...
/ISSUED 450 PM MST Tue Dec 16 2014/
Tonight through Thursday...Relatively quiet conditions over
central and north central Montana during the period. Areas of
freezing fog continue to cover portions of north central Montana
this afternoon...and those areas that did burn off will likely
see the fog redevelop late this afternoon or this evening. Have
extended the Freezing Fog Advisory for most of north central
Montana until 11 a.m. Wednesday.

Upper air pattern shows a high pressure ridge over the Rocky
Mountain states with a low pressure trough over the west coast.
Idiosyncrasies in the pattern are resulting in a split flow aloft
over southwest and central Montana...and small weather systems
embedded in the flow, and being steered into Montana, are being
sheared apart and weakened. Best chance for snow from these
systems will be over the southwest Montana mountains. Probabilities
decrease to only slight chances as the system moves to the
northeast over central Montana. As the high pressure ridge shifts
east and the trough begins to move inland, another system will
approach the area during the day Thursday. This again brings slight
chances for snow mainly over the west and southwest mountains.
Temperatures will remain near seasonal averages for this time of
year.

Thursday Night through Tuesday...A weak upper level ridge of high
pressure will keep the forecast area mostly dry Thursday night and
Friday. A shortwave trough will then move into the area Friday
night into Saturday, bringing an increased chance of mountain
snow. However, breezy westerly downslope winds will keep the
plains dry. The weather pattern will change somewhat beginning on
Sunday. An upper level ridge of high pressure will strengthen off
the California coast and an upper level trough of low pressure
will deepen from Hudson Bay into the Great Lakes. This will put
Montana under the influence of a strong northwesterly flow aloft.
The strongest winds aloft (60 to 70 kt at 700 mb) will occur
Sunday into Monday with the passage of a disturbance embedded in
the flow. This set- up will bring gusty westerly downslope winds
to much of the area, but especially over the plains of north
central Montana. In fact, some areas along the Rocky Mountain
Front could approach High Wind criteria (40 mph sustained/58 mph
gusts). Confidence is increasing that High Wind highlights may be
needed for this event. There is also significant moisture with
this disturbance, so have increased the chance for precipitation
out onto the plains. Although the winds will decrease somewhat
after the passage of the disturbance, the northwesterly flow aloft
will remain fairly moist, so have kept the chance for
precipitation above climatological normals across the area into
Tuesday. The breezy winds throughout the period will keep
temperatures around 10 degrees above normal. The warmest day of
the period appears to be Monday, when most lower elevation
locations should get well into the 40s. Coulston

&&

.PRELIMINARY POINT TEMPS/POPS...
GTF  17  37  25  37 /  50  30  10  10
CTB  18  34  22  36 /  10  10  10  10
HLN  23  31  18  33 /  80  20  10  20
BZN  18  31  14  30 /  90  20  10  20
WEY  21  31  17  28 / 100  40  20  30
DLN  22  33  17  33 / 100  20  10  20
HVR  17  31  19  35 /   0  30  20  10
LWT  14  38  22  39 /  60  40  10  10

&&

.TFX WATCHES/WARNINGS/ADVISORIES...
FREEZING FOG ADVISORY until 11 AM MST Wednesday Cascade...
Eastern Teton...Judith Basin...Southern Rocky Mountain Front.

FREEZING FOG ADVISORY until 11 AM MST Wednesday Eastern
Glacier...Eastern Pondera...Northern Rocky Mountain Front...
Toole.

&&

$$

weather.gov/greatfalls
www.twitter.com/NWSGreatFalls
www.facebook.com/NWSGreatFalls




000
FXUS65 KTFX 170415
AFDTFX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREAT FALLS MT
915 PM MST Tue Dec 16 2014

.UPDATE...
A band of light snow continues to push northward from Southwest
Montana into Central Montana. However...as this band pushes
northward...it is weakening a bit. Thus Bozeman...Helena...Great
Falls and Lewistown look to be on the edges of this system and
these locations will generally see just some minor snow
accumulations. The heavier swath of around an inch of snowfall
should move through the Dillon...Whitehall...Townsend and Kings
Hill region. I have precip extending northward into the Havre area
on Wednesday morning...but any snowfall in this region will be
quite light...generally less than a quarter of an inch. In terms
of fog...I have left the highlights alone...as patchy dense fog
continues to affect portions of the region. The fog might not be
as widespread in the Great Falls/Stanford areas right now...but
just enough fog around to keep the highlight going for now. The Cut
Bank area continues to have visibility around 1/4SM so the advisory
looks good in this region. Overnight lows are on track...with just
a few minor adjustments towards current readings. Brusda

&&

.AVIATION...
UPDATED 2350Z.
Light snow continues to push northward into Southwest MT. Expect
visibilities to generally be 1SM in areas of snow along with
mountains obscured. The snow will spread into the Helena/Bozeman
areas this evening...and then into the Great Falls/Lewistown areas
over night. The snow should move into the Havre area on Wednesday
morning. Areas of dense fog will continue to affect the Cut Bank
area until Wednesday morning. Brusda

&&

.PREV DISCUSSION...
/ISSUED 450 PM MST Tue Dec 16 2014/
Tonight through Thursday...Relatively quiet conditions over
central and north central Montana during the period. Areas of
freezing fog continue to cover portions of north central Montana
this afternoon...and those areas that did burn off will likely
see the fog redevelop late this afternoon or this evening. Have
extended the Freezing Fog Advisory for most of north central
Montana until 11 a.m. Wednesday.

Upper air pattern shows a high pressure ridge over the Rocky
Mountain states with a low pressure trough over the west coast.
Idiosyncrasies in the pattern are resulting in a split flow aloft
over southwest and central Montana...and small weather systems
embedded in the flow, and being steered into Montana, are being
sheared apart and weakened. Best chance for snow from these
systems will be over the southwest Montana mountains. Probabilities
decrease to only slight chances as the system moves to the
northeast over central Montana. As the high pressure ridge shifts
east and the trough begins to move inland, another system will
approach the area during the day Thursday. This again brings slight
chances for snow mainly over the west and southwest mountains.
Temperatures will remain near seasonal averages for this time of
year.

Thursday Night through Tuesday...A weak upper level ridge of high
pressure will keep the forecast area mostly dry Thursday night and
Friday. A shortwave trough will then move into the area Friday
night into Saturday, bringing an increased chance of mountain
snow. However, breezy westerly downslope winds will keep the
plains dry. The weather pattern will change somewhat beginning on
Sunday. An upper level ridge of high pressure will strengthen off
the California coast and an upper level trough of low pressure
will deepen from Hudson Bay into the Great Lakes. This will put
Montana under the influence of a strong northwesterly flow aloft.
The strongest winds aloft (60 to 70 kt at 700 mb) will occur
Sunday into Monday with the passage of a disturbance embedded in
the flow. This set- up will bring gusty westerly downslope winds
to much of the area, but especially over the plains of north
central Montana. In fact, some areas along the Rocky Mountain
Front could approach High Wind criteria (40 mph sustained/58 mph
gusts). Confidence is increasing that High Wind highlights may be
needed for this event. There is also significant moisture with
this disturbance, so have increased the chance for precipitation
out onto the plains. Although the winds will decrease somewhat
after the passage of the disturbance, the northwesterly flow aloft
will remain fairly moist, so have kept the chance for
precipitation above climatological normals across the area into
Tuesday. The breezy winds throughout the period will keep
temperatures around 10 degrees above normal. The warmest day of
the period appears to be Monday, when most lower elevation
locations should get well into the 40s. Coulston

&&

.PRELIMINARY POINT TEMPS/POPS...
GTF  17  37  25  37 /  50  30  10  10
CTB  18  34  22  36 /  10  10  10  10
HLN  23  31  18  33 /  80  20  10  20
BZN  18  31  14  30 /  90  20  10  20
WEY  21  31  17  28 / 100  40  20  30
DLN  22  33  17  33 / 100  20  10  20
HVR  17  31  19  35 /   0  30  20  10
LWT  14  38  22  39 /  60  40  10  10

&&

.TFX WATCHES/WARNINGS/ADVISORIES...
FREEZING FOG ADVISORY until 11 AM MST Wednesday Cascade...
Eastern Teton...Judith Basin...Southern Rocky Mountain Front.

FREEZING FOG ADVISORY until 11 AM MST Wednesday Eastern
Glacier...Eastern Pondera...Northern Rocky Mountain Front...
Toole.

&&

$$

weather.gov/greatfalls
www.twitter.com/NWSGreatFalls
www.facebook.com/NWSGreatFalls




000
FXUS65 KTFX 170415
AFDTFX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREAT FALLS MT
915 PM MST Tue Dec 16 2014

.UPDATE...
A band of light snow continues to push northward from Southwest
Montana into Central Montana. However...as this band pushes
northward...it is weakening a bit. Thus Bozeman...Helena...Great
Falls and Lewistown look to be on the edges of this system and
these locations will generally see just some minor snow
accumulations. The heavier swath of around an inch of snowfall
should move through the Dillon...Whitehall...Townsend and Kings
Hill region. I have precip extending northward into the Havre area
on Wednesday morning...but any snowfall in this region will be
quite light...generally less than a quarter of an inch. In terms
of fog...I have left the highlights alone...as patchy dense fog
continues to affect portions of the region. The fog might not be
as widespread in the Great Falls/Stanford areas right now...but
just enough fog around to keep the highlight going for now. The Cut
Bank area continues to have visibility around 1/4SM so the advisory
looks good in this region. Overnight lows are on track...with just
a few minor adjustments towards current readings. Brusda

&&

.AVIATION...
UPDATED 2350Z.
Light snow continues to push northward into Southwest MT. Expect
visibilities to generally be 1SM in areas of snow along with
mountains obscured. The snow will spread into the Helena/Bozeman
areas this evening...and then into the Great Falls/Lewistown areas
over night. The snow should move into the Havre area on Wednesday
morning. Areas of dense fog will continue to affect the Cut Bank
area until Wednesday morning. Brusda

&&

.PREV DISCUSSION...
/ISSUED 450 PM MST Tue Dec 16 2014/
Tonight through Thursday...Relatively quiet conditions over
central and north central Montana during the period. Areas of
freezing fog continue to cover portions of north central Montana
this afternoon...and those areas that did burn off will likely
see the fog redevelop late this afternoon or this evening. Have
extended the Freezing Fog Advisory for most of north central
Montana until 11 a.m. Wednesday.

Upper air pattern shows a high pressure ridge over the Rocky
Mountain states with a low pressure trough over the west coast.
Idiosyncrasies in the pattern are resulting in a split flow aloft
over southwest and central Montana...and small weather systems
embedded in the flow, and being steered into Montana, are being
sheared apart and weakened. Best chance for snow from these
systems will be over the southwest Montana mountains. Probabilities
decrease to only slight chances as the system moves to the
northeast over central Montana. As the high pressure ridge shifts
east and the trough begins to move inland, another system will
approach the area during the day Thursday. This again brings slight
chances for snow mainly over the west and southwest mountains.
Temperatures will remain near seasonal averages for this time of
year.

Thursday Night through Tuesday...A weak upper level ridge of high
pressure will keep the forecast area mostly dry Thursday night and
Friday. A shortwave trough will then move into the area Friday
night into Saturday, bringing an increased chance of mountain
snow. However, breezy westerly downslope winds will keep the
plains dry. The weather pattern will change somewhat beginning on
Sunday. An upper level ridge of high pressure will strengthen off
the California coast and an upper level trough of low pressure
will deepen from Hudson Bay into the Great Lakes. This will put
Montana under the influence of a strong northwesterly flow aloft.
The strongest winds aloft (60 to 70 kt at 700 mb) will occur
Sunday into Monday with the passage of a disturbance embedded in
the flow. This set- up will bring gusty westerly downslope winds
to much of the area, but especially over the plains of north
central Montana. In fact, some areas along the Rocky Mountain
Front could approach High Wind criteria (40 mph sustained/58 mph
gusts). Confidence is increasing that High Wind highlights may be
needed for this event. There is also significant moisture with
this disturbance, so have increased the chance for precipitation
out onto the plains. Although the winds will decrease somewhat
after the passage of the disturbance, the northwesterly flow aloft
will remain fairly moist, so have kept the chance for
precipitation above climatological normals across the area into
Tuesday. The breezy winds throughout the period will keep
temperatures around 10 degrees above normal. The warmest day of
the period appears to be Monday, when most lower elevation
locations should get well into the 40s. Coulston

&&

.PRELIMINARY POINT TEMPS/POPS...
GTF  17  37  25  37 /  50  30  10  10
CTB  18  34  22  36 /  10  10  10  10
HLN  23  31  18  33 /  80  20  10  20
BZN  18  31  14  30 /  90  20  10  20
WEY  21  31  17  28 / 100  40  20  30
DLN  22  33  17  33 / 100  20  10  20
HVR  17  31  19  35 /   0  30  20  10
LWT  14  38  22  39 /  60  40  10  10

&&

.TFX WATCHES/WARNINGS/ADVISORIES...
FREEZING FOG ADVISORY until 11 AM MST Wednesday Cascade...
Eastern Teton...Judith Basin...Southern Rocky Mountain Front.

FREEZING FOG ADVISORY until 11 AM MST Wednesday Eastern
Glacier...Eastern Pondera...Northern Rocky Mountain Front...
Toole.

&&

$$

weather.gov/greatfalls
www.twitter.com/NWSGreatFalls
www.facebook.com/NWSGreatFalls




000
FXUS65 KBYZ 170350
AFDBYZ

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE BILLINGS MT
850 PM MST TUE DEC 16 2014

.UPDATE...

SPOTTER AND SHERIFF/S OFFICE REPORTS AS OF MID EVENING SUGGEST FOG
IS NOT PARTICULARLY DENSE EXCEPT WHERE LOW CEILINGS ARE MEETING UP
WITH HIGHER RIDGETOPS. THAT EXPLAINS THE REPORTS WE/VE RECEIVED OF
1/2 TO 1/4SM VISIBILITY BOTH NEAR THE BULL MOUNTAINS AND MOLT. THE
HRRR SUGGESTS THAT IF MORE WIDESPREAD DENSE FOG OCCURS IT COULD BE
ALONG A LINE FROM ABOUT BILLINGS TO HARDIN AND SHERIDAN AFTER MID-
NIGHT...BUT CONFIDENCE IS NOT HIGH AND IN THE MEANTIME THERE ISN/T
ANY EVIDENCE IN OBSERVATIONS AND REPORTS THAT A DENSE FOG ADVISORY
IS NEEDED RIGHT NOW. THE AREAS OF FOG MENTIONED IN THE FORECAST IS
LIKELY THE BEST WAY OF HANDLING THE SITUATION RIGHT NOW. WE DID GO
AHEAD AND EXTEND A MENTION OF PATCHY FOG INTO WEDNESDAY MORNING IN
THE ROUNDUP...HYSHAM...LAME DEER....BROADUS AND EKALAKA AREAS WITH
RECENT HRRR SOLUTIONS IN MIND.

OTHERWISE...THE GOING FORECAST /INCLUDING OUR EARLIER UPDATE WHICH
INVOLVED POPS IN PARTS OF SOUTH CENTRAL MT/ IS ON TRACK AND SO THE
FORECAST ONLY NEEDED MINOR CHANGES WITH THIS UPDATE. SCHULTZ

&&

.SHORT TERM...VALID FOR WED AND THU...

AREAS OF FOG STILL PERSISTING ACROSS PORTIONS OF SC/SE MT THIS
AFTERNOON. MOIST UPSLOPE FLOW OF AIR WITH LIGHT WINDS ALOFT IS
ALLOWING FOG TO CONTINUE OVER THE AREA. VISIBILITY HAS BEEN
IMPROVING OVER OUR WESTERN ZONES LATE THIS AFTERNOON AS A WEAK
DISTURBANCE MOVES TOWARD OUR REGION AND IS SPREADING MID LEVEL
CLOUD DECK ACROSS THE AREA. WILL GO AHEAD AND DROP THE DENSE FOG
ADVISORY FOR OUR WESTERN ZONES WITH IMPROVING VISIBILITIES. HRRR
IS SHOWING MOIST UPSLOPE FLOW TO CONTINUE OVERNIGHT AND FOG WILL
AGAIN BE POSSIBLE OVER MUCH OF OUR FORECAST AREA. MOISTURE NOT
AS DEEP AS THE PREVIOUS NIGHT AND DO NOT EXPECT WIDESPREAD FOG
WITH VISIBILITY BELOW A 1/2 MILE.

UPPER WAVE WILL DRIFT SLOWLY ACROSS THE AREA WEDNESDAY AS 300 MB
JET STAYS WELL SOUTH OF US. WEAK QG FORCING WITH THIS WAVE WILL
BRING SOME LIGHT SNOW TO THE PLAINS TOMORROW BUT NO SNOW
ACCUMULATIONS ARE EXPECTED. DRY WEATHER RETURNING TO THE PLAINS
WEDNESDAY NIGHT THROUGH THURSDAY AS WEAK SHORT WAVE RIDGING
MOVES ACROSS THE REGION. SOME MOUNTAIN SNOW SHOWERS WILL CONTINUE
THROUGH THIS PERIOD BUT AMOUNTS WILL BE LIGHT. WITH INCREASING
HEIGHTS WEDNESDAY AND THURSDAY...TEMPERATURES WILL CLIMB BACK TO
NEAR SEASONAL NORMALS. RICHMOND

.LONG TERM...VALID FOR FRI...SAT...SUN...MON...TUE...

MODELS CONTINUE TO INCREASE CONFIDENCE IN THE EXTENDED. BOTH THE
OPERATIONAL GFS AND ECMWF GENERALLY FIT WITHIN THE SPREAD OF THE
ENSEMBLE DATA. WEAK PACIFIC RIDGE WILL MOVE IN TO THE STATE
FRIDAY. SATURDAY ANOTHER SHORTWAVE WILL MOVE THROUGH...AS THE FLOW
INCREASES AND BECOMES MORE NORTHWESTERLY. PRECIP CHANCES WILL
INCREASE IN THE MOUNTAINS.

SUNDAY WILL SEE SOME LEESIDE TROUGHING DEVELOP. WINDS WILL PICKUP
AROUND NYE AND LIVINGSTON AS THE PRESSURE GRADIENT TIGHTENS DURING
THE DAY SUNDAY. WINDS WILL BEGIN TO INCREASE SUNDAY NIGHT TO AROUND
BILLINGS. FOR MONDAY...IT STILL LOOKS LIKE A COLD FRONT WILL MOVE
THROUGH AS A SURFACE LOW DROPS OUT OF CANADA...BRING PRECIP TO
MUCH OF THE AREA. AS WITH THE PREVIOUS FORECAST...MODELS CONTINUE
TO DEVELOP AN ATMOSPHERIC RIVER...GIVING THE AREA PLENTY OF
MOISTURE. WITH THIS STILL A LONG WAY OFF...HAVE OPTED TO CONTINUE
SIMILAR POPS TO THE PREVIOUS FORECAST. GIVEN THAT TEMPERATURES
WILL STILL BE WARM...LOOKS LIKE MUCH OF THE CENTRAL ZONES WILL
SEE RAIN THAT WILL SWITCH TO SNOW AS TEMPERATURES DROP MONDAY
NIGHT. REIMER

&&

.AVIATION...

PERSISTENT LOW CIGS WILL KEEP FLIGHT CONDITIONS SUB-VFR IN ALL
LOCATIONS...WITH AS LOW AS VLIFR IN SOME LOCATIONS OVERNIGHT.
AREAS OF FOG ARE AGAIN POSSIBLE ACROSS THE REGION OVERNIGHT...AS
WELL AS SNOW OVER AREA MOUNTAINS AND NEAR FOOTHILLS REGIONS.
WIDESPREAD MOUNTAIN OBSCURATIONS ARE EXPECTED THROUGH THE NIGHT.
FLIGHT CONDITIONS ARE EXPECTED TO IMPROVE THROUGH THE DAY
WEDNESDAY. AAG

&&

.PRELIMINARY POINT TEMP/POPS...

    WED     THU     FRI     SAT     SUN     MON     TUE
-----------------------------------------------------------
BIL 020/036 022/039 023/038 027/042 026/044 035/047 030/041
    11/E    01/B    10/U    11/B    13/W    34/W    33/W
LVM 022/040 023/042 023/040 026/043 026/044 036/047 030/043
    42/J    11/E    11/B    11/N    13/W    33/W    33/W
HDN 014/032 015/037 016/037 020/040 019/041 029/044 026/040
    01/E    01/B    10/U    01/B    12/W    33/W    33/W
MLS 014/029 016/036 019/037 019/039 022/041 030/043 026/039
    11/E    01/B    10/U    01/B    11/B    33/W    32/W
4BQ 014/030 016/040 018/040 017/041 020/043 030/045 027/041
    02/J    01/B    11/B    00/B    11/B    33/W    32/W
BHK 011/025 015/035 019/037 017/039 020/040 027/041 024/037
    02/J    11/B    11/B    01/U    01/B    33/W    22/J
SHR 015/038 015/038 016/038 019/040 019/041 028/043 025/040
    01/B    01/B    10/U    01/B    12/J    34/W    43/W

&&

.BYZ WATCHES/WARNINGS/ADVISORIES...
MT...NONE.
WY...NONE.

&&

$$
WEATHER.GOV/BILLINGS



000
FXUS65 KBYZ 170350
AFDBYZ

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE BILLINGS MT
850 PM MST TUE DEC 16 2014

.UPDATE...

SPOTTER AND SHERIFF/S OFFICE REPORTS AS OF MID EVENING SUGGEST FOG
IS NOT PARTICULARLY DENSE EXCEPT WHERE LOW CEILINGS ARE MEETING UP
WITH HIGHER RIDGETOPS. THAT EXPLAINS THE REPORTS WE/VE RECEIVED OF
1/2 TO 1/4SM VISIBILITY BOTH NEAR THE BULL MOUNTAINS AND MOLT. THE
HRRR SUGGESTS THAT IF MORE WIDESPREAD DENSE FOG OCCURS IT COULD BE
ALONG A LINE FROM ABOUT BILLINGS TO HARDIN AND SHERIDAN AFTER MID-
NIGHT...BUT CONFIDENCE IS NOT HIGH AND IN THE MEANTIME THERE ISN/T
ANY EVIDENCE IN OBSERVATIONS AND REPORTS THAT A DENSE FOG ADVISORY
IS NEEDED RIGHT NOW. THE AREAS OF FOG MENTIONED IN THE FORECAST IS
LIKELY THE BEST WAY OF HANDLING THE SITUATION RIGHT NOW. WE DID GO
AHEAD AND EXTEND A MENTION OF PATCHY FOG INTO WEDNESDAY MORNING IN
THE ROUNDUP...HYSHAM...LAME DEER....BROADUS AND EKALAKA AREAS WITH
RECENT HRRR SOLUTIONS IN MIND.

OTHERWISE...THE GOING FORECAST /INCLUDING OUR EARLIER UPDATE WHICH
INVOLVED POPS IN PARTS OF SOUTH CENTRAL MT/ IS ON TRACK AND SO THE
FORECAST ONLY NEEDED MINOR CHANGES WITH THIS UPDATE. SCHULTZ

&&

.SHORT TERM...VALID FOR WED AND THU...

AREAS OF FOG STILL PERSISTING ACROSS PORTIONS OF SC/SE MT THIS
AFTERNOON. MOIST UPSLOPE FLOW OF AIR WITH LIGHT WINDS ALOFT IS
ALLOWING FOG TO CONTINUE OVER THE AREA. VISIBILITY HAS BEEN
IMPROVING OVER OUR WESTERN ZONES LATE THIS AFTERNOON AS A WEAK
DISTURBANCE MOVES TOWARD OUR REGION AND IS SPREADING MID LEVEL
CLOUD DECK ACROSS THE AREA. WILL GO AHEAD AND DROP THE DENSE FOG
ADVISORY FOR OUR WESTERN ZONES WITH IMPROVING VISIBILITIES. HRRR
IS SHOWING MOIST UPSLOPE FLOW TO CONTINUE OVERNIGHT AND FOG WILL
AGAIN BE POSSIBLE OVER MUCH OF OUR FORECAST AREA. MOISTURE NOT
AS DEEP AS THE PREVIOUS NIGHT AND DO NOT EXPECT WIDESPREAD FOG
WITH VISIBILITY BELOW A 1/2 MILE.

UPPER WAVE WILL DRIFT SLOWLY ACROSS THE AREA WEDNESDAY AS 300 MB
JET STAYS WELL SOUTH OF US. WEAK QG FORCING WITH THIS WAVE WILL
BRING SOME LIGHT SNOW TO THE PLAINS TOMORROW BUT NO SNOW
ACCUMULATIONS ARE EXPECTED. DRY WEATHER RETURNING TO THE PLAINS
WEDNESDAY NIGHT THROUGH THURSDAY AS WEAK SHORT WAVE RIDGING
MOVES ACROSS THE REGION. SOME MOUNTAIN SNOW SHOWERS WILL CONTINUE
THROUGH THIS PERIOD BUT AMOUNTS WILL BE LIGHT. WITH INCREASING
HEIGHTS WEDNESDAY AND THURSDAY...TEMPERATURES WILL CLIMB BACK TO
NEAR SEASONAL NORMALS. RICHMOND

.LONG TERM...VALID FOR FRI...SAT...SUN...MON...TUE...

MODELS CONTINUE TO INCREASE CONFIDENCE IN THE EXTENDED. BOTH THE
OPERATIONAL GFS AND ECMWF GENERALLY FIT WITHIN THE SPREAD OF THE
ENSEMBLE DATA. WEAK PACIFIC RIDGE WILL MOVE IN TO THE STATE
FRIDAY. SATURDAY ANOTHER SHORTWAVE WILL MOVE THROUGH...AS THE FLOW
INCREASES AND BECOMES MORE NORTHWESTERLY. PRECIP CHANCES WILL
INCREASE IN THE MOUNTAINS.

SUNDAY WILL SEE SOME LEESIDE TROUGHING DEVELOP. WINDS WILL PICKUP
AROUND NYE AND LIVINGSTON AS THE PRESSURE GRADIENT TIGHTENS DURING
THE DAY SUNDAY. WINDS WILL BEGIN TO INCREASE SUNDAY NIGHT TO AROUND
BILLINGS. FOR MONDAY...IT STILL LOOKS LIKE A COLD FRONT WILL MOVE
THROUGH AS A SURFACE LOW DROPS OUT OF CANADA...BRING PRECIP TO
MUCH OF THE AREA. AS WITH THE PREVIOUS FORECAST...MODELS CONTINUE
TO DEVELOP AN ATMOSPHERIC RIVER...GIVING THE AREA PLENTY OF
MOISTURE. WITH THIS STILL A LONG WAY OFF...HAVE OPTED TO CONTINUE
SIMILAR POPS TO THE PREVIOUS FORECAST. GIVEN THAT TEMPERATURES
WILL STILL BE WARM...LOOKS LIKE MUCH OF THE CENTRAL ZONES WILL
SEE RAIN THAT WILL SWITCH TO SNOW AS TEMPERATURES DROP MONDAY
NIGHT. REIMER

&&

.AVIATION...

PERSISTENT LOW CIGS WILL KEEP FLIGHT CONDITIONS SUB-VFR IN ALL
LOCATIONS...WITH AS LOW AS VLIFR IN SOME LOCATIONS OVERNIGHT.
AREAS OF FOG ARE AGAIN POSSIBLE ACROSS THE REGION OVERNIGHT...AS
WELL AS SNOW OVER AREA MOUNTAINS AND NEAR FOOTHILLS REGIONS.
WIDESPREAD MOUNTAIN OBSCURATIONS ARE EXPECTED THROUGH THE NIGHT.
FLIGHT CONDITIONS ARE EXPECTED TO IMPROVE THROUGH THE DAY
WEDNESDAY. AAG

&&

.PRELIMINARY POINT TEMP/POPS...

    WED     THU     FRI     SAT     SUN     MON     TUE
-----------------------------------------------------------
BIL 020/036 022/039 023/038 027/042 026/044 035/047 030/041
    11/E    01/B    10/U    11/B    13/W    34/W    33/W
LVM 022/040 023/042 023/040 026/043 026/044 036/047 030/043
    42/J    11/E    11/B    11/N    13/W    33/W    33/W
HDN 014/032 015/037 016/037 020/040 019/041 029/044 026/040
    01/E    01/B    10/U    01/B    12/W    33/W    33/W
MLS 014/029 016/036 019/037 019/039 022/041 030/043 026/039
    11/E    01/B    10/U    01/B    11/B    33/W    32/W
4BQ 014/030 016/040 018/040 017/041 020/043 030/045 027/041
    02/J    01/B    11/B    00/B    11/B    33/W    32/W
BHK 011/025 015/035 019/037 017/039 020/040 027/041 024/037
    02/J    11/B    11/B    01/U    01/B    33/W    22/J
SHR 015/038 015/038 016/038 019/040 019/041 028/043 025/040
    01/B    01/B    10/U    01/B    12/J    34/W    43/W

&&

.BYZ WATCHES/WARNINGS/ADVISORIES...
MT...NONE.
WY...NONE.

&&

$$
WEATHER.GOV/BILLINGS



000
FXUS65 KBYZ 170350
AFDBYZ

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE BILLINGS MT
850 PM MST TUE DEC 16 2014

.UPDATE...

SPOTTER AND SHERIFF/S OFFICE REPORTS AS OF MID EVENING SUGGEST FOG
IS NOT PARTICULARLY DENSE EXCEPT WHERE LOW CEILINGS ARE MEETING UP
WITH HIGHER RIDGETOPS. THAT EXPLAINS THE REPORTS WE/VE RECEIVED OF
1/2 TO 1/4SM VISIBILITY BOTH NEAR THE BULL MOUNTAINS AND MOLT. THE
HRRR SUGGESTS THAT IF MORE WIDESPREAD DENSE FOG OCCURS IT COULD BE
ALONG A LINE FROM ABOUT BILLINGS TO HARDIN AND SHERIDAN AFTER MID-
NIGHT...BUT CONFIDENCE IS NOT HIGH AND IN THE MEANTIME THERE ISN/T
ANY EVIDENCE IN OBSERVATIONS AND REPORTS THAT A DENSE FOG ADVISORY
IS NEEDED RIGHT NOW. THE AREAS OF FOG MENTIONED IN THE FORECAST IS
LIKELY THE BEST WAY OF HANDLING THE SITUATION RIGHT NOW. WE DID GO
AHEAD AND EXTEND A MENTION OF PATCHY FOG INTO WEDNESDAY MORNING IN
THE ROUNDUP...HYSHAM...LAME DEER....BROADUS AND EKALAKA AREAS WITH
RECENT HRRR SOLUTIONS IN MIND.

OTHERWISE...THE GOING FORECAST /INCLUDING OUR EARLIER UPDATE WHICH
INVOLVED POPS IN PARTS OF SOUTH CENTRAL MT/ IS ON TRACK AND SO THE
FORECAST ONLY NEEDED MINOR CHANGES WITH THIS UPDATE. SCHULTZ

&&

.SHORT TERM...VALID FOR WED AND THU...

AREAS OF FOG STILL PERSISTING ACROSS PORTIONS OF SC/SE MT THIS
AFTERNOON. MOIST UPSLOPE FLOW OF AIR WITH LIGHT WINDS ALOFT IS
ALLOWING FOG TO CONTINUE OVER THE AREA. VISIBILITY HAS BEEN
IMPROVING OVER OUR WESTERN ZONES LATE THIS AFTERNOON AS A WEAK
DISTURBANCE MOVES TOWARD OUR REGION AND IS SPREADING MID LEVEL
CLOUD DECK ACROSS THE AREA. WILL GO AHEAD AND DROP THE DENSE FOG
ADVISORY FOR OUR WESTERN ZONES WITH IMPROVING VISIBILITIES. HRRR
IS SHOWING MOIST UPSLOPE FLOW TO CONTINUE OVERNIGHT AND FOG WILL
AGAIN BE POSSIBLE OVER MUCH OF OUR FORECAST AREA. MOISTURE NOT
AS DEEP AS THE PREVIOUS NIGHT AND DO NOT EXPECT WIDESPREAD FOG
WITH VISIBILITY BELOW A 1/2 MILE.

UPPER WAVE WILL DRIFT SLOWLY ACROSS THE AREA WEDNESDAY AS 300 MB
JET STAYS WELL SOUTH OF US. WEAK QG FORCING WITH THIS WAVE WILL
BRING SOME LIGHT SNOW TO THE PLAINS TOMORROW BUT NO SNOW
ACCUMULATIONS ARE EXPECTED. DRY WEATHER RETURNING TO THE PLAINS
WEDNESDAY NIGHT THROUGH THURSDAY AS WEAK SHORT WAVE RIDGING
MOVES ACROSS THE REGION. SOME MOUNTAIN SNOW SHOWERS WILL CONTINUE
THROUGH THIS PERIOD BUT AMOUNTS WILL BE LIGHT. WITH INCREASING
HEIGHTS WEDNESDAY AND THURSDAY...TEMPERATURES WILL CLIMB BACK TO
NEAR SEASONAL NORMALS. RICHMOND

.LONG TERM...VALID FOR FRI...SAT...SUN...MON...TUE...

MODELS CONTINUE TO INCREASE CONFIDENCE IN THE EXTENDED. BOTH THE
OPERATIONAL GFS AND ECMWF GENERALLY FIT WITHIN THE SPREAD OF THE
ENSEMBLE DATA. WEAK PACIFIC RIDGE WILL MOVE IN TO THE STATE
FRIDAY. SATURDAY ANOTHER SHORTWAVE WILL MOVE THROUGH...AS THE FLOW
INCREASES AND BECOMES MORE NORTHWESTERLY. PRECIP CHANCES WILL
INCREASE IN THE MOUNTAINS.

SUNDAY WILL SEE SOME LEESIDE TROUGHING DEVELOP. WINDS WILL PICKUP
AROUND NYE AND LIVINGSTON AS THE PRESSURE GRADIENT TIGHTENS DURING
THE DAY SUNDAY. WINDS WILL BEGIN TO INCREASE SUNDAY NIGHT TO AROUND
BILLINGS. FOR MONDAY...IT STILL LOOKS LIKE A COLD FRONT WILL MOVE
THROUGH AS A SURFACE LOW DROPS OUT OF CANADA...BRING PRECIP TO
MUCH OF THE AREA. AS WITH THE PREVIOUS FORECAST...MODELS CONTINUE
TO DEVELOP AN ATMOSPHERIC RIVER...GIVING THE AREA PLENTY OF
MOISTURE. WITH THIS STILL A LONG WAY OFF...HAVE OPTED TO CONTINUE
SIMILAR POPS TO THE PREVIOUS FORECAST. GIVEN THAT TEMPERATURES
WILL STILL BE WARM...LOOKS LIKE MUCH OF THE CENTRAL ZONES WILL
SEE RAIN THAT WILL SWITCH TO SNOW AS TEMPERATURES DROP MONDAY
NIGHT. REIMER

&&

.AVIATION...

PERSISTENT LOW CIGS WILL KEEP FLIGHT CONDITIONS SUB-VFR IN ALL
LOCATIONS...WITH AS LOW AS VLIFR IN SOME LOCATIONS OVERNIGHT.
AREAS OF FOG ARE AGAIN POSSIBLE ACROSS THE REGION OVERNIGHT...AS
WELL AS SNOW OVER AREA MOUNTAINS AND NEAR FOOTHILLS REGIONS.
WIDESPREAD MOUNTAIN OBSCURATIONS ARE EXPECTED THROUGH THE NIGHT.
FLIGHT CONDITIONS ARE EXPECTED TO IMPROVE THROUGH THE DAY
WEDNESDAY. AAG

&&

.PRELIMINARY POINT TEMP/POPS...

    WED     THU     FRI     SAT     SUN     MON     TUE
-----------------------------------------------------------
BIL 020/036 022/039 023/038 027/042 026/044 035/047 030/041
    11/E    01/B    10/U    11/B    13/W    34/W    33/W
LVM 022/040 023/042 023/040 026/043 026/044 036/047 030/043
    42/J    11/E    11/B    11/N    13/W    33/W    33/W
HDN 014/032 015/037 016/037 020/040 019/041 029/044 026/040
    01/E    01/B    10/U    01/B    12/W    33/W    33/W
MLS 014/029 016/036 019/037 019/039 022/041 030/043 026/039
    11/E    01/B    10/U    01/B    11/B    33/W    32/W
4BQ 014/030 016/040 018/040 017/041 020/043 030/045 027/041
    02/J    01/B    11/B    00/B    11/B    33/W    32/W
BHK 011/025 015/035 019/037 017/039 020/040 027/041 024/037
    02/J    11/B    11/B    01/U    01/B    33/W    22/J
SHR 015/038 015/038 016/038 019/040 019/041 028/043 025/040
    01/B    01/B    10/U    01/B    12/J    34/W    43/W

&&

.BYZ WATCHES/WARNINGS/ADVISORIES...
MT...NONE.
WY...NONE.

&&

$$
WEATHER.GOV/BILLINGS



000
FXUS65 KBYZ 170350
AFDBYZ

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE BILLINGS MT
850 PM MST TUE DEC 16 2014

.UPDATE...

SPOTTER AND SHERIFF/S OFFICE REPORTS AS OF MID EVENING SUGGEST FOG
IS NOT PARTICULARLY DENSE EXCEPT WHERE LOW CEILINGS ARE MEETING UP
WITH HIGHER RIDGETOPS. THAT EXPLAINS THE REPORTS WE/VE RECEIVED OF
1/2 TO 1/4SM VISIBILITY BOTH NEAR THE BULL MOUNTAINS AND MOLT. THE
HRRR SUGGESTS THAT IF MORE WIDESPREAD DENSE FOG OCCURS IT COULD BE
ALONG A LINE FROM ABOUT BILLINGS TO HARDIN AND SHERIDAN AFTER MID-
NIGHT...BUT CONFIDENCE IS NOT HIGH AND IN THE MEANTIME THERE ISN/T
ANY EVIDENCE IN OBSERVATIONS AND REPORTS THAT A DENSE FOG ADVISORY
IS NEEDED RIGHT NOW. THE AREAS OF FOG MENTIONED IN THE FORECAST IS
LIKELY THE BEST WAY OF HANDLING THE SITUATION RIGHT NOW. WE DID GO
AHEAD AND EXTEND A MENTION OF PATCHY FOG INTO WEDNESDAY MORNING IN
THE ROUNDUP...HYSHAM...LAME DEER....BROADUS AND EKALAKA AREAS WITH
RECENT HRRR SOLUTIONS IN MIND.

OTHERWISE...THE GOING FORECAST /INCLUDING OUR EARLIER UPDATE WHICH
INVOLVED POPS IN PARTS OF SOUTH CENTRAL MT/ IS ON TRACK AND SO THE
FORECAST ONLY NEEDED MINOR CHANGES WITH THIS UPDATE. SCHULTZ

&&

.SHORT TERM...VALID FOR WED AND THU...

AREAS OF FOG STILL PERSISTING ACROSS PORTIONS OF SC/SE MT THIS
AFTERNOON. MOIST UPSLOPE FLOW OF AIR WITH LIGHT WINDS ALOFT IS
ALLOWING FOG TO CONTINUE OVER THE AREA. VISIBILITY HAS BEEN
IMPROVING OVER OUR WESTERN ZONES LATE THIS AFTERNOON AS A WEAK
DISTURBANCE MOVES TOWARD OUR REGION AND IS SPREADING MID LEVEL
CLOUD DECK ACROSS THE AREA. WILL GO AHEAD AND DROP THE DENSE FOG
ADVISORY FOR OUR WESTERN ZONES WITH IMPROVING VISIBILITIES. HRRR
IS SHOWING MOIST UPSLOPE FLOW TO CONTINUE OVERNIGHT AND FOG WILL
AGAIN BE POSSIBLE OVER MUCH OF OUR FORECAST AREA. MOISTURE NOT
AS DEEP AS THE PREVIOUS NIGHT AND DO NOT EXPECT WIDESPREAD FOG
WITH VISIBILITY BELOW A 1/2 MILE.

UPPER WAVE WILL DRIFT SLOWLY ACROSS THE AREA WEDNESDAY AS 300 MB
JET STAYS WELL SOUTH OF US. WEAK QG FORCING WITH THIS WAVE WILL
BRING SOME LIGHT SNOW TO THE PLAINS TOMORROW BUT NO SNOW
ACCUMULATIONS ARE EXPECTED. DRY WEATHER RETURNING TO THE PLAINS
WEDNESDAY NIGHT THROUGH THURSDAY AS WEAK SHORT WAVE RIDGING
MOVES ACROSS THE REGION. SOME MOUNTAIN SNOW SHOWERS WILL CONTINUE
THROUGH THIS PERIOD BUT AMOUNTS WILL BE LIGHT. WITH INCREASING
HEIGHTS WEDNESDAY AND THURSDAY...TEMPERATURES WILL CLIMB BACK TO
NEAR SEASONAL NORMALS. RICHMOND

.LONG TERM...VALID FOR FRI...SAT...SUN...MON...TUE...

MODELS CONTINUE TO INCREASE CONFIDENCE IN THE EXTENDED. BOTH THE
OPERATIONAL GFS AND ECMWF GENERALLY FIT WITHIN THE SPREAD OF THE
ENSEMBLE DATA. WEAK PACIFIC RIDGE WILL MOVE IN TO THE STATE
FRIDAY. SATURDAY ANOTHER SHORTWAVE WILL MOVE THROUGH...AS THE FLOW
INCREASES AND BECOMES MORE NORTHWESTERLY. PRECIP CHANCES WILL
INCREASE IN THE MOUNTAINS.

SUNDAY WILL SEE SOME LEESIDE TROUGHING DEVELOP. WINDS WILL PICKUP
AROUND NYE AND LIVINGSTON AS THE PRESSURE GRADIENT TIGHTENS DURING
THE DAY SUNDAY. WINDS WILL BEGIN TO INCREASE SUNDAY NIGHT TO AROUND
BILLINGS. FOR MONDAY...IT STILL LOOKS LIKE A COLD FRONT WILL MOVE
THROUGH AS A SURFACE LOW DROPS OUT OF CANADA...BRING PRECIP TO
MUCH OF THE AREA. AS WITH THE PREVIOUS FORECAST...MODELS CONTINUE
TO DEVELOP AN ATMOSPHERIC RIVER...GIVING THE AREA PLENTY OF
MOISTURE. WITH THIS STILL A LONG WAY OFF...HAVE OPTED TO CONTINUE
SIMILAR POPS TO THE PREVIOUS FORECAST. GIVEN THAT TEMPERATURES
WILL STILL BE WARM...LOOKS LIKE MUCH OF THE CENTRAL ZONES WILL
SEE RAIN THAT WILL SWITCH TO SNOW AS TEMPERATURES DROP MONDAY
NIGHT. REIMER

&&

.AVIATION...

PERSISTENT LOW CIGS WILL KEEP FLIGHT CONDITIONS SUB-VFR IN ALL
LOCATIONS...WITH AS LOW AS VLIFR IN SOME LOCATIONS OVERNIGHT.
AREAS OF FOG ARE AGAIN POSSIBLE ACROSS THE REGION OVERNIGHT...AS
WELL AS SNOW OVER AREA MOUNTAINS AND NEAR FOOTHILLS REGIONS.
WIDESPREAD MOUNTAIN OBSCURATIONS ARE EXPECTED THROUGH THE NIGHT.
FLIGHT CONDITIONS ARE EXPECTED TO IMPROVE THROUGH THE DAY
WEDNESDAY. AAG

&&

.PRELIMINARY POINT TEMP/POPS...

    WED     THU     FRI     SAT     SUN     MON     TUE
-----------------------------------------------------------
BIL 020/036 022/039 023/038 027/042 026/044 035/047 030/041
    11/E    01/B    10/U    11/B    13/W    34/W    33/W
LVM 022/040 023/042 023/040 026/043 026/044 036/047 030/043
    42/J    11/E    11/B    11/N    13/W    33/W    33/W
HDN 014/032 015/037 016/037 020/040 019/041 029/044 026/040
    01/E    01/B    10/U    01/B    12/W    33/W    33/W
MLS 014/029 016/036 019/037 019/039 022/041 030/043 026/039
    11/E    01/B    10/U    01/B    11/B    33/W    32/W
4BQ 014/030 016/040 018/040 017/041 020/043 030/045 027/041
    02/J    01/B    11/B    00/B    11/B    33/W    32/W
BHK 011/025 015/035 019/037 017/039 020/040 027/041 024/037
    02/J    11/B    11/B    01/U    01/B    33/W    22/J
SHR 015/038 015/038 016/038 019/040 019/041 028/043 025/040
    01/B    01/B    10/U    01/B    12/J    34/W    43/W

&&

.BYZ WATCHES/WARNINGS/ADVISORIES...
MT...NONE.
WY...NONE.

&&

$$
WEATHER.GOV/BILLINGS



000
FXUS65 KBYZ 170350
AFDBYZ

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE BILLINGS MT
850 PM MST TUE DEC 16 2014

.UPDATE...

SPOTTER AND SHERIFF/S OFFICE REPORTS AS OF MID EVENING SUGGEST FOG
IS NOT PARTICULARLY DENSE EXCEPT WHERE LOW CEILINGS ARE MEETING UP
WITH HIGHER RIDGETOPS. THAT EXPLAINS THE REPORTS WE/VE RECEIVED OF
1/2 TO 1/4SM VISIBILITY BOTH NEAR THE BULL MOUNTAINS AND MOLT. THE
HRRR SUGGESTS THAT IF MORE WIDESPREAD DENSE FOG OCCURS IT COULD BE
ALONG A LINE FROM ABOUT BILLINGS TO HARDIN AND SHERIDAN AFTER MID-
NIGHT...BUT CONFIDENCE IS NOT HIGH AND IN THE MEANTIME THERE ISN/T
ANY EVIDENCE IN OBSERVATIONS AND REPORTS THAT A DENSE FOG ADVISORY
IS NEEDED RIGHT NOW. THE AREAS OF FOG MENTIONED IN THE FORECAST IS
LIKELY THE BEST WAY OF HANDLING THE SITUATION RIGHT NOW. WE DID GO
AHEAD AND EXTEND A MENTION OF PATCHY FOG INTO WEDNESDAY MORNING IN
THE ROUNDUP...HYSHAM...LAME DEER....BROADUS AND EKALAKA AREAS WITH
RECENT HRRR SOLUTIONS IN MIND.

OTHERWISE...THE GOING FORECAST /INCLUDING OUR EARLIER UPDATE WHICH
INVOLVED POPS IN PARTS OF SOUTH CENTRAL MT/ IS ON TRACK AND SO THE
FORECAST ONLY NEEDED MINOR CHANGES WITH THIS UPDATE. SCHULTZ

&&

.SHORT TERM...VALID FOR WED AND THU...

AREAS OF FOG STILL PERSISTING ACROSS PORTIONS OF SC/SE MT THIS
AFTERNOON. MOIST UPSLOPE FLOW OF AIR WITH LIGHT WINDS ALOFT IS
ALLOWING FOG TO CONTINUE OVER THE AREA. VISIBILITY HAS BEEN
IMPROVING OVER OUR WESTERN ZONES LATE THIS AFTERNOON AS A WEAK
DISTURBANCE MOVES TOWARD OUR REGION AND IS SPREADING MID LEVEL
CLOUD DECK ACROSS THE AREA. WILL GO AHEAD AND DROP THE DENSE FOG
ADVISORY FOR OUR WESTERN ZONES WITH IMPROVING VISIBILITIES. HRRR
IS SHOWING MOIST UPSLOPE FLOW TO CONTINUE OVERNIGHT AND FOG WILL
AGAIN BE POSSIBLE OVER MUCH OF OUR FORECAST AREA. MOISTURE NOT
AS DEEP AS THE PREVIOUS NIGHT AND DO NOT EXPECT WIDESPREAD FOG
WITH VISIBILITY BELOW A 1/2 MILE.

UPPER WAVE WILL DRIFT SLOWLY ACROSS THE AREA WEDNESDAY AS 300 MB
JET STAYS WELL SOUTH OF US. WEAK QG FORCING WITH THIS WAVE WILL
BRING SOME LIGHT SNOW TO THE PLAINS TOMORROW BUT NO SNOW
ACCUMULATIONS ARE EXPECTED. DRY WEATHER RETURNING TO THE PLAINS
WEDNESDAY NIGHT THROUGH THURSDAY AS WEAK SHORT WAVE RIDGING
MOVES ACROSS THE REGION. SOME MOUNTAIN SNOW SHOWERS WILL CONTINUE
THROUGH THIS PERIOD BUT AMOUNTS WILL BE LIGHT. WITH INCREASING
HEIGHTS WEDNESDAY AND THURSDAY...TEMPERATURES WILL CLIMB BACK TO
NEAR SEASONAL NORMALS. RICHMOND

.LONG TERM...VALID FOR FRI...SAT...SUN...MON...TUE...

MODELS CONTINUE TO INCREASE CONFIDENCE IN THE EXTENDED. BOTH THE
OPERATIONAL GFS AND ECMWF GENERALLY FIT WITHIN THE SPREAD OF THE
ENSEMBLE DATA. WEAK PACIFIC RIDGE WILL MOVE IN TO THE STATE
FRIDAY. SATURDAY ANOTHER SHORTWAVE WILL MOVE THROUGH...AS THE FLOW
INCREASES AND BECOMES MORE NORTHWESTERLY. PRECIP CHANCES WILL
INCREASE IN THE MOUNTAINS.

SUNDAY WILL SEE SOME LEESIDE TROUGHING DEVELOP. WINDS WILL PICKUP
AROUND NYE AND LIVINGSTON AS THE PRESSURE GRADIENT TIGHTENS DURING
THE DAY SUNDAY. WINDS WILL BEGIN TO INCREASE SUNDAY NIGHT TO AROUND
BILLINGS. FOR MONDAY...IT STILL LOOKS LIKE A COLD FRONT WILL MOVE
THROUGH AS A SURFACE LOW DROPS OUT OF CANADA...BRING PRECIP TO
MUCH OF THE AREA. AS WITH THE PREVIOUS FORECAST...MODELS CONTINUE
TO DEVELOP AN ATMOSPHERIC RIVER...GIVING THE AREA PLENTY OF
MOISTURE. WITH THIS STILL A LONG WAY OFF...HAVE OPTED TO CONTINUE
SIMILAR POPS TO THE PREVIOUS FORECAST. GIVEN THAT TEMPERATURES
WILL STILL BE WARM...LOOKS LIKE MUCH OF THE CENTRAL ZONES WILL
SEE RAIN THAT WILL SWITCH TO SNOW AS TEMPERATURES DROP MONDAY
NIGHT. REIMER

&&

.AVIATION...

PERSISTENT LOW CIGS WILL KEEP FLIGHT CONDITIONS SUB-VFR IN ALL
LOCATIONS...WITH AS LOW AS VLIFR IN SOME LOCATIONS OVERNIGHT.
AREAS OF FOG ARE AGAIN POSSIBLE ACROSS THE REGION OVERNIGHT...AS
WELL AS SNOW OVER AREA MOUNTAINS AND NEAR FOOTHILLS REGIONS.
WIDESPREAD MOUNTAIN OBSCURATIONS ARE EXPECTED THROUGH THE NIGHT.
FLIGHT CONDITIONS ARE EXPECTED TO IMPROVE THROUGH THE DAY
WEDNESDAY. AAG

&&

.PRELIMINARY POINT TEMP/POPS...

    WED     THU     FRI     SAT     SUN     MON     TUE
-----------------------------------------------------------
BIL 020/036 022/039 023/038 027/042 026/044 035/047 030/041
    11/E    01/B    10/U    11/B    13/W    34/W    33/W
LVM 022/040 023/042 023/040 026/043 026/044 036/047 030/043
    42/J    11/E    11/B    11/N    13/W    33/W    33/W
HDN 014/032 015/037 016/037 020/040 019/041 029/044 026/040
    01/E    01/B    10/U    01/B    12/W    33/W    33/W
MLS 014/029 016/036 019/037 019/039 022/041 030/043 026/039
    11/E    01/B    10/U    01/B    11/B    33/W    32/W
4BQ 014/030 016/040 018/040 017/041 020/043 030/045 027/041
    02/J    01/B    11/B    00/B    11/B    33/W    32/W
BHK 011/025 015/035 019/037 017/039 020/040 027/041 024/037
    02/J    11/B    11/B    01/U    01/B    33/W    22/J
SHR 015/038 015/038 016/038 019/040 019/041 028/043 025/040
    01/B    01/B    10/U    01/B    12/J    34/W    43/W

&&

.BYZ WATCHES/WARNINGS/ADVISORIES...
MT...NONE.
WY...NONE.

&&

$$
WEATHER.GOV/BILLINGS



000
FXUS65 KBYZ 170350
AFDBYZ

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE BILLINGS MT
850 PM MST TUE DEC 16 2014

.UPDATE...

SPOTTER AND SHERIFF/S OFFICE REPORTS AS OF MID EVENING SUGGEST FOG
IS NOT PARTICULARLY DENSE EXCEPT WHERE LOW CEILINGS ARE MEETING UP
WITH HIGHER RIDGETOPS. THAT EXPLAINS THE REPORTS WE/VE RECEIVED OF
1/2 TO 1/4SM VISIBILITY BOTH NEAR THE BULL MOUNTAINS AND MOLT. THE
HRRR SUGGESTS THAT IF MORE WIDESPREAD DENSE FOG OCCURS IT COULD BE
ALONG A LINE FROM ABOUT BILLINGS TO HARDIN AND SHERIDAN AFTER MID-
NIGHT...BUT CONFIDENCE IS NOT HIGH AND IN THE MEANTIME THERE ISN/T
ANY EVIDENCE IN OBSERVATIONS AND REPORTS THAT A DENSE FOG ADVISORY
IS NEEDED RIGHT NOW. THE AREAS OF FOG MENTIONED IN THE FORECAST IS
LIKELY THE BEST WAY OF HANDLING THE SITUATION RIGHT NOW. WE DID GO
AHEAD AND EXTEND A MENTION OF PATCHY FOG INTO WEDNESDAY MORNING IN
THE ROUNDUP...HYSHAM...LAME DEER....BROADUS AND EKALAKA AREAS WITH
RECENT HRRR SOLUTIONS IN MIND.

OTHERWISE...THE GOING FORECAST /INCLUDING OUR EARLIER UPDATE WHICH
INVOLVED POPS IN PARTS OF SOUTH CENTRAL MT/ IS ON TRACK AND SO THE
FORECAST ONLY NEEDED MINOR CHANGES WITH THIS UPDATE. SCHULTZ

&&

.SHORT TERM...VALID FOR WED AND THU...

AREAS OF FOG STILL PERSISTING ACROSS PORTIONS OF SC/SE MT THIS
AFTERNOON. MOIST UPSLOPE FLOW OF AIR WITH LIGHT WINDS ALOFT IS
ALLOWING FOG TO CONTINUE OVER THE AREA. VISIBILITY HAS BEEN
IMPROVING OVER OUR WESTERN ZONES LATE THIS AFTERNOON AS A WEAK
DISTURBANCE MOVES TOWARD OUR REGION AND IS SPREADING MID LEVEL
CLOUD DECK ACROSS THE AREA. WILL GO AHEAD AND DROP THE DENSE FOG
ADVISORY FOR OUR WESTERN ZONES WITH IMPROVING VISIBILITIES. HRRR
IS SHOWING MOIST UPSLOPE FLOW TO CONTINUE OVERNIGHT AND FOG WILL
AGAIN BE POSSIBLE OVER MUCH OF OUR FORECAST AREA. MOISTURE NOT
AS DEEP AS THE PREVIOUS NIGHT AND DO NOT EXPECT WIDESPREAD FOG
WITH VISIBILITY BELOW A 1/2 MILE.

UPPER WAVE WILL DRIFT SLOWLY ACROSS THE AREA WEDNESDAY AS 300 MB
JET STAYS WELL SOUTH OF US. WEAK QG FORCING WITH THIS WAVE WILL
BRING SOME LIGHT SNOW TO THE PLAINS TOMORROW BUT NO SNOW
ACCUMULATIONS ARE EXPECTED. DRY WEATHER RETURNING TO THE PLAINS
WEDNESDAY NIGHT THROUGH THURSDAY AS WEAK SHORT WAVE RIDGING
MOVES ACROSS THE REGION. SOME MOUNTAIN SNOW SHOWERS WILL CONTINUE
THROUGH THIS PERIOD BUT AMOUNTS WILL BE LIGHT. WITH INCREASING
HEIGHTS WEDNESDAY AND THURSDAY...TEMPERATURES WILL CLIMB BACK TO
NEAR SEASONAL NORMALS. RICHMOND

.LONG TERM...VALID FOR FRI...SAT...SUN...MON...TUE...

MODELS CONTINUE TO INCREASE CONFIDENCE IN THE EXTENDED. BOTH THE
OPERATIONAL GFS AND ECMWF GENERALLY FIT WITHIN THE SPREAD OF THE
ENSEMBLE DATA. WEAK PACIFIC RIDGE WILL MOVE IN TO THE STATE
FRIDAY. SATURDAY ANOTHER SHORTWAVE WILL MOVE THROUGH...AS THE FLOW
INCREASES AND BECOMES MORE NORTHWESTERLY. PRECIP CHANCES WILL
INCREASE IN THE MOUNTAINS.

SUNDAY WILL SEE SOME LEESIDE TROUGHING DEVELOP. WINDS WILL PICKUP
AROUND NYE AND LIVINGSTON AS THE PRESSURE GRADIENT TIGHTENS DURING
THE DAY SUNDAY. WINDS WILL BEGIN TO INCREASE SUNDAY NIGHT TO AROUND
BILLINGS. FOR MONDAY...IT STILL LOOKS LIKE A COLD FRONT WILL MOVE
THROUGH AS A SURFACE LOW DROPS OUT OF CANADA...BRING PRECIP TO
MUCH OF THE AREA. AS WITH THE PREVIOUS FORECAST...MODELS CONTINUE
TO DEVELOP AN ATMOSPHERIC RIVER...GIVING THE AREA PLENTY OF
MOISTURE. WITH THIS STILL A LONG WAY OFF...HAVE OPTED TO CONTINUE
SIMILAR POPS TO THE PREVIOUS FORECAST. GIVEN THAT TEMPERATURES
WILL STILL BE WARM...LOOKS LIKE MUCH OF THE CENTRAL ZONES WILL
SEE RAIN THAT WILL SWITCH TO SNOW AS TEMPERATURES DROP MONDAY
NIGHT. REIMER

&&

.AVIATION...

PERSISTENT LOW CIGS WILL KEEP FLIGHT CONDITIONS SUB-VFR IN ALL
LOCATIONS...WITH AS LOW AS VLIFR IN SOME LOCATIONS OVERNIGHT.
AREAS OF FOG ARE AGAIN POSSIBLE ACROSS THE REGION OVERNIGHT...AS
WELL AS SNOW OVER AREA MOUNTAINS AND NEAR FOOTHILLS REGIONS.
WIDESPREAD MOUNTAIN OBSCURATIONS ARE EXPECTED THROUGH THE NIGHT.
FLIGHT CONDITIONS ARE EXPECTED TO IMPROVE THROUGH THE DAY
WEDNESDAY. AAG

&&

.PRELIMINARY POINT TEMP/POPS...

    WED     THU     FRI     SAT     SUN     MON     TUE
-----------------------------------------------------------
BIL 020/036 022/039 023/038 027/042 026/044 035/047 030/041
    11/E    01/B    10/U    11/B    13/W    34/W    33/W
LVM 022/040 023/042 023/040 026/043 026/044 036/047 030/043
    42/J    11/E    11/B    11/N    13/W    33/W    33/W
HDN 014/032 015/037 016/037 020/040 019/041 029/044 026/040
    01/E    01/B    10/U    01/B    12/W    33/W    33/W
MLS 014/029 016/036 019/037 019/039 022/041 030/043 026/039
    11/E    01/B    10/U    01/B    11/B    33/W    32/W
4BQ 014/030 016/040 018/040 017/041 020/043 030/045 027/041
    02/J    01/B    11/B    00/B    11/B    33/W    32/W
BHK 011/025 015/035 019/037 017/039 020/040 027/041 024/037
    02/J    11/B    11/B    01/U    01/B    33/W    22/J
SHR 015/038 015/038 016/038 019/040 019/041 028/043 025/040
    01/B    01/B    10/U    01/B    12/J    34/W    43/W

&&

.BYZ WATCHES/WARNINGS/ADVISORIES...
MT...NONE.
WY...NONE.

&&

$$
WEATHER.GOV/BILLINGS




000
FXUS65 KGGW 170302 AAA
AFDGGW

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE GLASGOW MT
802 PM MST TUE DEC 16 2014

.SHORT TERM...FOR NORTHEAST MONTANA...TONIGHT THROUGH THURSDAY...
UPDATE...
INCREASED SKY COVER AND ADJUSTED TEMPERATURES UP A FEW DEGREES AS
THE BLANKET OF STRATUS LOOKS TO CONTINUE THROUGH THE OVERNIGHT
HOURS ACROSS THE REGION. OTHERWISE NO ADDITIONAL CHANGES MADE TO
THE FORECAST.   PROTON

PREVIOUS DISCUSSION...
WARM DRY AIRMASS OVER A COLD MOIST LAYER NEAR THE SURFACE HAS
ALLOWED FOR FOR A STUBBORN WIDESPREAD STRATUS CLOUD DECK TO HANG
AROUND THE REGION TODAY. SATELLITE SHOWING IT EXTENDING FAR UPSTREAM
INTO THE CENTRAL PLAINS...SO THIS CLOUD DECK WILL REMAIN WITH US FOR
SOMETIME AS LONG AS OUR LOW LEVEL FLOW REMAINS FROM THE SOUTHEAST.

A SYSTEM WILL COMPLICATE THINGS A BIT AS IT MOVES INTO THE WESTERN
ZONES WEDNESDAY AND DIMINISHING AS IT MOVES EAST ACROSS THE CWA.
MOST OF THE PRECIPITATION LOOKS TO BE IN THE FORM OF SNOW BUT THERE
COULD BE AN ISOLATED LOCATION WHERE THERE ARE A FEW DROPS OF
FREEZING RAIN...SOMETHING THAT LOOKS A LOT LESS IMPACTFUL THAN
WHAT WE HAD SUNDAY. THEREFORE...NOT ANTICIPATING A BIG SHOW WITH
THIS SYSTEM.

BEHIND THIS SYSTEM...WINDS THURSDAY TURN AROUND TO THE SOUTHWEST.
THIS WILL ALLOW A WARMER AIRMASS TO MOVE IN AND TEMPS WARM INTO
THE UPPER 20S NORTH TO 30S TO AROUND 40 SOUTH. TFJ


.LONG TERM...THURSDAY NIGHT THROUGH TUESDAY...
THE 12Z GUIDANCE HAS SOMEWHAT MILDER TEMPERATURES THROUGH THE
EXTENDED PERIOD AS COMPARED WITH THE INHERITED FORECAST. GIVEN THE
POTENTIAL FOR THE NEXT WEATHER SYSTEM TO APPROACH IN NORTHWEST
FLOW ALOFT BY LATE NEXT WEEKEND...FELT THAT TEMPERATURES COULD BE
CRITICAL FOR DECIPHERING PRECIPITATION TYPE. THEREFORE DID SPEND
SOME TIME ON TEMPERATURE GRIDS WITH THIS PACKAGE.

THE LONG RANGE PERIOD WILL GET UNDERWAY THURSDAY NIGHT AND FRIDAY
WITH AN UPPER LEVEL RIDGE OVER MONTANA HELPING TO MAINTAIN FAIRLY
DRY CONDITIONS. ZONAL TO NORTHWEST FLOW ALOFT ENSUES BEHIND THE
RIDGE AS IT TRANSLATES EAST. A SHORTWAVE LOOKS TO APPROACH BY LATE
IN THE WEEKEND AND COMBINE WITH MOISTURE AS IT APPROACHES THE CWA.
PVA SHOULD HELP PROVIDE FORCING FOR ASCENT IN A MOISTENING
VERTICAL COLUMN. THE LATEST NOMADS ENSEMBLE PROBABILITY TOOL
SUGGESTS MEASURABLE PRECIPITATION IS A DECENT BET AS EARLY AS 00Z
MONDAY. THIS HAS SUPPORT FROM THE 12Z GFS AND ECMWF OPERATIONAL
MODELS. THERE ARE DIFFERENCES THOUGH ON TIMING/PLACEMENT OF BEST
DYNAMIC FORCING FOR ASCENT...AND SO FOR NOW DECIDED TO MAINTAIN
POPS IN THE SLIGHT CHANCE RANGE. BASED ON THIS REASONING
HOWEVER...DID NOT FEEL COMFORTABLE MAINTAINING A DRY FORECAST FOR
SUNDAY AND SUNDAY NIGHT. THERE IS PLENTY OF SUPPORT FOR A SLIGHT
CHANCE OF PRECIPITATION DURING THIS TIME AND GRIDS NOW REFLECT THIS.

THERMAL PROFILES THOUGH INDICATE THAT PRECIPITATION TYPE COULD BE
COMPLEX. FOR NOW WILL GO WITH A WINTRY MIX STARTING SUNDAY AND
WILL CONTINUE CHANCES INTO EARLY NEXT WEEK FOLLOWING SLIGHT
CHANCE/NEAR CLIMO POPS. AS MODELS SHOW BETTER CONSENSUS AND/OR RUN
TO RUN CONTINUITY...FINER AND MORE CONFIDENT DETAIL IN THE
FORECAST SHOULD RESULT OVER TIME. MALIAWCO

PREVIOUS LONG TERM DISCUSSION...
SYNOPTIC SET UP... WITH WEAK POOLED COLD AIR AT THE SURFACE OVER
THE EASTERN GREAT PLAINS. A RIDGE RUNS UP THE COAST FROM
CALIFORNIA TO SOUTHERN BRITISH COLUMBIA. NORTHEAST MONTANA LIES
BETWEEN THESE TWO FEATURES IN A UNENERGETIC WEAK NORTHWESTERN
FLOW. COLDEST AIR OF THE NORTHERN HEMISPHERE LIES BOTTLED UP OVER
THE ARCTIC.

THURSDAY NIGHT THROUGH SUNDAY... RIDGE TO THE WEST GAINS
INCREASING INFLUENCE AND PLACES NORTHEAST MONTANA UNDER PARTLY
CLOUDY AND DRY CONDITIONS DUE TO A STABLE ATMOSPHERE. SUBTLE
SHORTWAVES APPEAR IN THE FLOW... ESPECIALLY ON SATURDAY... BUT
REMAIN RELATIVELY UN-ENERGIZED AND SEEM INSUFFICIENT TO CAUSE
PRECIPITATION AT THIS TIME.

SUNDAY NIGHT ONWARD... WESTERN RIDGE WILL FINALLY MOVE THROUGH
THE AREA AND GENERATE CONDITIONS FOR A PREFRONTAL WARMING SPIKE
ON SUNDAY NIGHT. BY MONDAY AN ARCTIC INTRUSION IS ANTICIPATED TO
BEGIN AND WILL BRING A COLD FRONT THROUGH THE REGION. POSSIBLE
PACIFIC MOISTURE AT THE CREST OF THE EXITING RIDGE COULD HELP TO
GENERATE SHOWER STARTING DURING THIS PERIOD AND LASTING THROUGH
TUESDAY. AFTERWARD TEMPERATURES ARE EXPECTED TO BEGIN DROPPING
OFF.

GAH

&&

.AVIATION...

AN MVFR TO IFR STRATUS DECK WILL CONTINUE OVER THE TAF SITES
TONIGHT. PATCHY FREEZING FOG IS ALSO POSSIBLE WHICH COULD LEAD TO
RESTRICTED VISIBILITY AT TIMES. CONFIDENCE ON FOG HOWEVER IS
CURRENTLY LOW. SOUTHEAST WINDS WILL PERSIST AROUND 10 KTS.
MALIAWCO/MICKELSON


&&

.GLASGOW WATCHES/WARNINGS/ADVISORIES...NONE.

&&

$$

WEATHER.GOV/GLASGOW





000
FXUS65 KGGW 170302 AAA
AFDGGW

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE GLASGOW MT
802 PM MST TUE DEC 16 2014

.SHORT TERM...FOR NORTHEAST MONTANA...TONIGHT THROUGH THURSDAY...
UPDATE...
INCREASED SKY COVER AND ADJUSTED TEMPERATURES UP A FEW DEGREES AS
THE BLANKET OF STRATUS LOOKS TO CONTINUE THROUGH THE OVERNIGHT
HOURS ACROSS THE REGION. OTHERWISE NO ADDITIONAL CHANGES MADE TO
THE FORECAST.   PROTON

PREVIOUS DISCUSSION...
WARM DRY AIRMASS OVER A COLD MOIST LAYER NEAR THE SURFACE HAS
ALLOWED FOR FOR A STUBBORN WIDESPREAD STRATUS CLOUD DECK TO HANG
AROUND THE REGION TODAY. SATELLITE SHOWING IT EXTENDING FAR UPSTREAM
INTO THE CENTRAL PLAINS...SO THIS CLOUD DECK WILL REMAIN WITH US FOR
SOMETIME AS LONG AS OUR LOW LEVEL FLOW REMAINS FROM THE SOUTHEAST.

A SYSTEM WILL COMPLICATE THINGS A BIT AS IT MOVES INTO THE WESTERN
ZONES WEDNESDAY AND DIMINISHING AS IT MOVES EAST ACROSS THE CWA.
MOST OF THE PRECIPITATION LOOKS TO BE IN THE FORM OF SNOW BUT THERE
COULD BE AN ISOLATED LOCATION WHERE THERE ARE A FEW DROPS OF
FREEZING RAIN...SOMETHING THAT LOOKS A LOT LESS IMPACTFUL THAN
WHAT WE HAD SUNDAY. THEREFORE...NOT ANTICIPATING A BIG SHOW WITH
THIS SYSTEM.

BEHIND THIS SYSTEM...WINDS THURSDAY TURN AROUND TO THE SOUTHWEST.
THIS WILL ALLOW A WARMER AIRMASS TO MOVE IN AND TEMPS WARM INTO
THE UPPER 20S NORTH TO 30S TO AROUND 40 SOUTH. TFJ


.LONG TERM...THURSDAY NIGHT THROUGH TUESDAY...
THE 12Z GUIDANCE HAS SOMEWHAT MILDER TEMPERATURES THROUGH THE
EXTENDED PERIOD AS COMPARED WITH THE INHERITED FORECAST. GIVEN THE
POTENTIAL FOR THE NEXT WEATHER SYSTEM TO APPROACH IN NORTHWEST
FLOW ALOFT BY LATE NEXT WEEKEND...FELT THAT TEMPERATURES COULD BE
CRITICAL FOR DECIPHERING PRECIPITATION TYPE. THEREFORE DID SPEND
SOME TIME ON TEMPERATURE GRIDS WITH THIS PACKAGE.

THE LONG RANGE PERIOD WILL GET UNDERWAY THURSDAY NIGHT AND FRIDAY
WITH AN UPPER LEVEL RIDGE OVER MONTANA HELPING TO MAINTAIN FAIRLY
DRY CONDITIONS. ZONAL TO NORTHWEST FLOW ALOFT ENSUES BEHIND THE
RIDGE AS IT TRANSLATES EAST. A SHORTWAVE LOOKS TO APPROACH BY LATE
IN THE WEEKEND AND COMBINE WITH MOISTURE AS IT APPROACHES THE CWA.
PVA SHOULD HELP PROVIDE FORCING FOR ASCENT IN A MOISTENING
VERTICAL COLUMN. THE LATEST NOMADS ENSEMBLE PROBABILITY TOOL
SUGGESTS MEASURABLE PRECIPITATION IS A DECENT BET AS EARLY AS 00Z
MONDAY. THIS HAS SUPPORT FROM THE 12Z GFS AND ECMWF OPERATIONAL
MODELS. THERE ARE DIFFERENCES THOUGH ON TIMING/PLACEMENT OF BEST
DYNAMIC FORCING FOR ASCENT...AND SO FOR NOW DECIDED TO MAINTAIN
POPS IN THE SLIGHT CHANCE RANGE. BASED ON THIS REASONING
HOWEVER...DID NOT FEEL COMFORTABLE MAINTAINING A DRY FORECAST FOR
SUNDAY AND SUNDAY NIGHT. THERE IS PLENTY OF SUPPORT FOR A SLIGHT
CHANCE OF PRECIPITATION DURING THIS TIME AND GRIDS NOW REFLECT THIS.

THERMAL PROFILES THOUGH INDICATE THAT PRECIPITATION TYPE COULD BE
COMPLEX. FOR NOW WILL GO WITH A WINTRY MIX STARTING SUNDAY AND
WILL CONTINUE CHANCES INTO EARLY NEXT WEEK FOLLOWING SLIGHT
CHANCE/NEAR CLIMO POPS. AS MODELS SHOW BETTER CONSENSUS AND/OR RUN
TO RUN CONTINUITY...FINER AND MORE CONFIDENT DETAIL IN THE
FORECAST SHOULD RESULT OVER TIME. MALIAWCO

PREVIOUS LONG TERM DISCUSSION...
SYNOPTIC SET UP... WITH WEAK POOLED COLD AIR AT THE SURFACE OVER
THE EASTERN GREAT PLAINS. A RIDGE RUNS UP THE COAST FROM
CALIFORNIA TO SOUTHERN BRITISH COLUMBIA. NORTHEAST MONTANA LIES
BETWEEN THESE TWO FEATURES IN A UNENERGETIC WEAK NORTHWESTERN
FLOW. COLDEST AIR OF THE NORTHERN HEMISPHERE LIES BOTTLED UP OVER
THE ARCTIC.

THURSDAY NIGHT THROUGH SUNDAY... RIDGE TO THE WEST GAINS
INCREASING INFLUENCE AND PLACES NORTHEAST MONTANA UNDER PARTLY
CLOUDY AND DRY CONDITIONS DUE TO A STABLE ATMOSPHERE. SUBTLE
SHORTWAVES APPEAR IN THE FLOW... ESPECIALLY ON SATURDAY... BUT
REMAIN RELATIVELY UN-ENERGIZED AND SEEM INSUFFICIENT TO CAUSE
PRECIPITATION AT THIS TIME.

SUNDAY NIGHT ONWARD... WESTERN RIDGE WILL FINALLY MOVE THROUGH
THE AREA AND GENERATE CONDITIONS FOR A PREFRONTAL WARMING SPIKE
ON SUNDAY NIGHT. BY MONDAY AN ARCTIC INTRUSION IS ANTICIPATED TO
BEGIN AND WILL BRING A COLD FRONT THROUGH THE REGION. POSSIBLE
PACIFIC MOISTURE AT THE CREST OF THE EXITING RIDGE COULD HELP TO
GENERATE SHOWER STARTING DURING THIS PERIOD AND LASTING THROUGH
TUESDAY. AFTERWARD TEMPERATURES ARE EXPECTED TO BEGIN DROPPING
OFF.

GAH

&&

.AVIATION...

AN MVFR TO IFR STRATUS DECK WILL CONTINUE OVER THE TAF SITES
TONIGHT. PATCHY FREEZING FOG IS ALSO POSSIBLE WHICH COULD LEAD TO
RESTRICTED VISIBILITY AT TIMES. CONFIDENCE ON FOG HOWEVER IS
CURRENTLY LOW. SOUTHEAST WINDS WILL PERSIST AROUND 10 KTS.
MALIAWCO/MICKELSON


&&

.GLASGOW WATCHES/WARNINGS/ADVISORIES...NONE.

&&

$$

WEATHER.GOV/GLASGOW






000
FXUS65 KBYZ 170112
AFDBYZ

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE BILLINGS MT
612 PM MST TUE DEC 16 2014

.UPDATE...

WE MADE A COLLABORATIVE FORECAST MOVE LED BY NWS GREAT FALLS THAT
MEANT INCREASING THE CHANCE OF SNOW TONIGHT IN THE LIVINGSTON AND
COOKE CITY AREAS NORTHEAST TOWARD HARLOWTON. WE EVEN ADDED A LOW-
END CHANCE OF SNOW TO THE RYEGATE AND ROUNDUP AREAS AFTER 06 UTC.
THIS CHANGE WAS MADE BASED ON UPSTREAM OBSERVATIONS OF LIGHT SNOW
WITH VISIBILITY BETWEEN 1 AND 3 SM FROM THE ID PANHANDLE AND THEN
INTO SOUTHWEST MONTANA AT DILLON AND BUTTE. FORECAST SOUNDINGS AT
LIVINGSTON ARE NOT ESPECIALLY SATURATED...BUT THERE WAS ENOUGH TO
INCREASE POPS INTO THE 40 PERCENT RANGE THERE AFTER 06 UTC. WE/LL
TAKE A ANOTHER LOOK AT THIS SITUATION BY 9 PM MST.

FOG STILL LOOKS LIKE THE MAIN WEATHER IMPACT TONIGHT...BUT SO FAR
WE HAVE NOT SEEN WIDESPREAD LOW VISIBILITY THAT REQUIRES ADVISORY
ISSUANCE. THAT WILL ALSO BE MONITORED THE NEXT FEW HOURS. SCHULTZ

&&

.SHORT TERM...VALID FOR WED AND THU...

AREAS OF FOG STILL PERSISTING ACROSS PORTIONS OF SC/SE MT THIS
AFTERNOON. MOIST UPSLOPE FLOW OF AIR WITH LIGHT WINDS ALOFT IS
ALLOWING FOG TO CONTINUE OVER THE AREA. VISIBILITY HAS BEEN
IMPROVING OVER OUR WESTERN ZONES LATE THIS AFTERNOON AS A WEAK
DISTURBANCE MOVES TOWARD OUR REGION AND IS SPREADING MID LEVEL
CLOUD DECK ACROSS THE AREA. WILL GO AHEAD AND DROP THE DENSE FOG
ADVISORY FOR OUR WESTERN ZONES WITH IMPROVING VISIBILITIES. HRRR
IS SHOWING MOIST UPSLOPE FLOW TO CONTINUE OVERNIGHT AND FOG WILL
AGAIN BE POSSIBLE OVER MUCH OF OUR FORECAST AREA. MOISTURE NOT
AS DEEP AS THE PREVIOUS NIGHT AND DO NOT EXPECT WIDESPREAD FOG
WITH VISIBILITY BELOW A 1/2 MILE.

UPPER WAVE WILL DRIFT SLOWLY ACROSS THE AREA WEDNESDAY AS 300 MB
JET STAYS WELL SOUTH OF US. WEAK QG FORCING WITH THIS WAVE WILL
BRING SOME LIGHT SNOW TO THE PLAINS TOMORROW BUT NO SNOW
ACCUMULATIONS ARE EXPECTED. DRY WEATHER RETURNING TO THE PLAINS
WEDNESDAY NIGHT THROUGH THURSDAY AS WEAK SHORT WAVE RIDGING
MOVES ACROSS THE REGION. SOME MOUNTAIN SNOW SHOWERS WILL CONTINUE
THROUGH THIS PERIOD BUT AMOUNTS WILL BE LIGHT. WITH INCREASING
HEIGHTS WEDNESDAY AND THURSDAY...TEMPERATURES WILL CLIMB BACK TO
NEAR SEASONAL NORMALS. RICHMOND

.LONG TERM...VALID FOR FRI...SAT...SUN...MON...TUE...

MODELS CONTINUE TO INCREASE CONFIDENCE IN THE EXTENDED. BOTH THE
OPERATIONAL GFS AND ECMWF GENERALLY FIT WITHIN THE SPREAD OF THE
ENSEMBLE DATA. WEAK PACIFIC RIDGE WILL MOVE IN TO THE STATE
FRIDAY. SATURDAY ANOTHER SHORTWAVE WILL MOVE THROUGH...AS THE FLOW
INCREASES AND BECOMES MORE NORTHWESTERLY. PRECIP CHANCES WILL
INCREASE IN THE MOUNTAINS.

SUNDAY WILL SEE SOME LEESIDE TROUGHING DEVELOP. WINDS WILL PICKUP
AROUND NYE AND LIVINGSTON AS THE PRESSURE GRADIENT TIGHTENS DURING
THE DAY SUNDAY. WINDS WILL BEGIN TO INCREASE SUNDAY NIGHT TO AROUND
BILLINGS. FOR MONDAY...IT STILL LOOKS LIKE A COLD FRONT WILL MOVE
THROUGH AS A SURFACE LOW DROPS OUT OF CANADA...BRING PRECIP TO
MUCH OF THE AREA. AS WITH THE PREVIOUS FORECAST...MODELS CONTINUE
TO DEVELOP AN ATMOSPHERIC RIVER...GIVING THE AREA PLENTY OF
MOISTURE. WITH THIS STILL A LONG WAY OFF...HAVE OPTED TO CONTINUE
SIMILAR POPS TO THE PREVIOUS FORECAST. GIVEN THAT TEMPERATURES
WILL STILL BE WARM...LOOKS LIKE MUCH OF THE CENTRAL ZONES WILL
SEE RAIN THAT WILL SWITCH TO SNOW AS TEMPERATURES DROP MONDAY
NIGHT. REIMER

&&

.AVIATION...

PERSISTENT LOW CIGS WILL KEEP FLIGHT CONDITIONS SUB-VFR IN ALL
LOCATIONS...WITH AS LOW AS VLIFR IN SOME LOCATIONS OVERNIGHT.
AREAS OF FOG ARE AGAIN POSSIBLE ACROSS THE REGION OVERNIGHT...AS
WELL AS SNOW OVER AREA MOUNTAINS AND NEAR FOOTHILLS REGIONS.
WIDESPREAD MOUNTAIN OBSCURATIONS ARE EXPECTED THROUGH THE NIGHT.
FLIGHT CONDITIONS ARE EXPECTED TO IMPROVE THROUGH THE DAY
WEDNESDAY. AAG

&&

.PRELIMINARY POINT TEMP/POPS...

    WED     THU     FRI     SAT     SUN     MON     TUE
-----------------------------------------------------------
BIL 020/036 022/039 023/038 027/042 026/044 035/047 030/041
    11/E    01/B    10/U    11/B    13/W    34/W    33/W
LVM 023/040 023/042 023/040 026/043 026/044 036/047 030/043
    42/J    11/E    11/B    11/N    13/W    33/W    33/W
HDN 014/032 015/037 016/037 020/040 019/041 029/044 026/040
    01/E    01/B    10/U    01/B    12/W    33/W    33/W
MLS 014/029 016/036 019/037 019/039 022/041 030/043 026/039
    11/E    01/B    10/U    01/B    11/B    33/W    32/W
4BQ 014/030 016/040 018/040 017/041 020/043 030/045 027/041
    02/J    01/B    11/B    00/B    11/B    33/W    32/W
BHK 011/025 015/035 019/037 017/039 020/040 027/041 024/037
    02/J    11/B    11/B    01/U    01/B    33/W    22/J
SHR 015/038 015/038 016/038 019/040 019/041 028/043 025/040
    01/B    01/B    10/U    01/B    12/J    34/W    43/W

&&

.BYZ WATCHES/WARNINGS/ADVISORIES...
MT...NONE.
WY...NONE.

&&

$$
WEATHER.GOV/BILLINGS




000
FXUS65 KBYZ 170112
AFDBYZ

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE BILLINGS MT
612 PM MST TUE DEC 16 2014

.UPDATE...

WE MADE A COLLABORATIVE FORECAST MOVE LED BY NWS GREAT FALLS THAT
MEANT INCREASING THE CHANCE OF SNOW TONIGHT IN THE LIVINGSTON AND
COOKE CITY AREAS NORTHEAST TOWARD HARLOWTON. WE EVEN ADDED A LOW-
END CHANCE OF SNOW TO THE RYEGATE AND ROUNDUP AREAS AFTER 06 UTC.
THIS CHANGE WAS MADE BASED ON UPSTREAM OBSERVATIONS OF LIGHT SNOW
WITH VISIBILITY BETWEEN 1 AND 3 SM FROM THE ID PANHANDLE AND THEN
INTO SOUTHWEST MONTANA AT DILLON AND BUTTE. FORECAST SOUNDINGS AT
LIVINGSTON ARE NOT ESPECIALLY SATURATED...BUT THERE WAS ENOUGH TO
INCREASE POPS INTO THE 40 PERCENT RANGE THERE AFTER 06 UTC. WE/LL
TAKE A ANOTHER LOOK AT THIS SITUATION BY 9 PM MST.

FOG STILL LOOKS LIKE THE MAIN WEATHER IMPACT TONIGHT...BUT SO FAR
WE HAVE NOT SEEN WIDESPREAD LOW VISIBILITY THAT REQUIRES ADVISORY
ISSUANCE. THAT WILL ALSO BE MONITORED THE NEXT FEW HOURS. SCHULTZ

&&

.SHORT TERM...VALID FOR WED AND THU...

AREAS OF FOG STILL PERSISTING ACROSS PORTIONS OF SC/SE MT THIS
AFTERNOON. MOIST UPSLOPE FLOW OF AIR WITH LIGHT WINDS ALOFT IS
ALLOWING FOG TO CONTINUE OVER THE AREA. VISIBILITY HAS BEEN
IMPROVING OVER OUR WESTERN ZONES LATE THIS AFTERNOON AS A WEAK
DISTURBANCE MOVES TOWARD OUR REGION AND IS SPREADING MID LEVEL
CLOUD DECK ACROSS THE AREA. WILL GO AHEAD AND DROP THE DENSE FOG
ADVISORY FOR OUR WESTERN ZONES WITH IMPROVING VISIBILITIES. HRRR
IS SHOWING MOIST UPSLOPE FLOW TO CONTINUE OVERNIGHT AND FOG WILL
AGAIN BE POSSIBLE OVER MUCH OF OUR FORECAST AREA. MOISTURE NOT
AS DEEP AS THE PREVIOUS NIGHT AND DO NOT EXPECT WIDESPREAD FOG
WITH VISIBILITY BELOW A 1/2 MILE.

UPPER WAVE WILL DRIFT SLOWLY ACROSS THE AREA WEDNESDAY AS 300 MB
JET STAYS WELL SOUTH OF US. WEAK QG FORCING WITH THIS WAVE WILL
BRING SOME LIGHT SNOW TO THE PLAINS TOMORROW BUT NO SNOW
ACCUMULATIONS ARE EXPECTED. DRY WEATHER RETURNING TO THE PLAINS
WEDNESDAY NIGHT THROUGH THURSDAY AS WEAK SHORT WAVE RIDGING
MOVES ACROSS THE REGION. SOME MOUNTAIN SNOW SHOWERS WILL CONTINUE
THROUGH THIS PERIOD BUT AMOUNTS WILL BE LIGHT. WITH INCREASING
HEIGHTS WEDNESDAY AND THURSDAY...TEMPERATURES WILL CLIMB BACK TO
NEAR SEASONAL NORMALS. RICHMOND

.LONG TERM...VALID FOR FRI...SAT...SUN...MON...TUE...

MODELS CONTINUE TO INCREASE CONFIDENCE IN THE EXTENDED. BOTH THE
OPERATIONAL GFS AND ECMWF GENERALLY FIT WITHIN THE SPREAD OF THE
ENSEMBLE DATA. WEAK PACIFIC RIDGE WILL MOVE IN TO THE STATE
FRIDAY. SATURDAY ANOTHER SHORTWAVE WILL MOVE THROUGH...AS THE FLOW
INCREASES AND BECOMES MORE NORTHWESTERLY. PRECIP CHANCES WILL
INCREASE IN THE MOUNTAINS.

SUNDAY WILL SEE SOME LEESIDE TROUGHING DEVELOP. WINDS WILL PICKUP
AROUND NYE AND LIVINGSTON AS THE PRESSURE GRADIENT TIGHTENS DURING
THE DAY SUNDAY. WINDS WILL BEGIN TO INCREASE SUNDAY NIGHT TO AROUND
BILLINGS. FOR MONDAY...IT STILL LOOKS LIKE A COLD FRONT WILL MOVE
THROUGH AS A SURFACE LOW DROPS OUT OF CANADA...BRING PRECIP TO
MUCH OF THE AREA. AS WITH THE PREVIOUS FORECAST...MODELS CONTINUE
TO DEVELOP AN ATMOSPHERIC RIVER...GIVING THE AREA PLENTY OF
MOISTURE. WITH THIS STILL A LONG WAY OFF...HAVE OPTED TO CONTINUE
SIMILAR POPS TO THE PREVIOUS FORECAST. GIVEN THAT TEMPERATURES
WILL STILL BE WARM...LOOKS LIKE MUCH OF THE CENTRAL ZONES WILL
SEE RAIN THAT WILL SWITCH TO SNOW AS TEMPERATURES DROP MONDAY
NIGHT. REIMER

&&

.AVIATION...

PERSISTENT LOW CIGS WILL KEEP FLIGHT CONDITIONS SUB-VFR IN ALL
LOCATIONS...WITH AS LOW AS VLIFR IN SOME LOCATIONS OVERNIGHT.
AREAS OF FOG ARE AGAIN POSSIBLE ACROSS THE REGION OVERNIGHT...AS
WELL AS SNOW OVER AREA MOUNTAINS AND NEAR FOOTHILLS REGIONS.
WIDESPREAD MOUNTAIN OBSCURATIONS ARE EXPECTED THROUGH THE NIGHT.
FLIGHT CONDITIONS ARE EXPECTED TO IMPROVE THROUGH THE DAY
WEDNESDAY. AAG

&&

.PRELIMINARY POINT TEMP/POPS...

    WED     THU     FRI     SAT     SUN     MON     TUE
-----------------------------------------------------------
BIL 020/036 022/039 023/038 027/042 026/044 035/047 030/041
    11/E    01/B    10/U    11/B    13/W    34/W    33/W
LVM 023/040 023/042 023/040 026/043 026/044 036/047 030/043
    42/J    11/E    11/B    11/N    13/W    33/W    33/W
HDN 014/032 015/037 016/037 020/040 019/041 029/044 026/040
    01/E    01/B    10/U    01/B    12/W    33/W    33/W
MLS 014/029 016/036 019/037 019/039 022/041 030/043 026/039
    11/E    01/B    10/U    01/B    11/B    33/W    32/W
4BQ 014/030 016/040 018/040 017/041 020/043 030/045 027/041
    02/J    01/B    11/B    00/B    11/B    33/W    32/W
BHK 011/025 015/035 019/037 017/039 020/040 027/041 024/037
    02/J    11/B    11/B    01/U    01/B    33/W    22/J
SHR 015/038 015/038 016/038 019/040 019/041 028/043 025/040
    01/B    01/B    10/U    01/B    12/J    34/W    43/W

&&

.BYZ WATCHES/WARNINGS/ADVISORIES...
MT...NONE.
WY...NONE.

&&

$$
WEATHER.GOV/BILLINGS



000
FXUS65 KTFX 170054
AFDTFX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREAT FALLS MT
554 PM MST Tue Dec 16 2014

.UPDATE...
Updated evening forecast to increase the chances for snow tonight
for Southwest and Central Montana. Overall a swath of snow will
move through the Dillon/Bozeman and Townsend areas this
evening...and then spread into the Helena/Great Falls/Lewistown
area late this evening and overnight. In the Havre area...if the
system holds together...the snow should move up into this region
generally after 4 am. Overall snow accumulations will generally be
around 1/2 inch...but there will be a few areas that get around an
inch of snow.

In terms of fog...with increasing clouds and precip chances...the
threat for widespread dense freezing fog redeveloping in the Great
Falls/Stanford areas is diminishing. If the fog does not redevelop
in the next few hours...this portion might be dropped from the
advisory. However...in the Cut Bank area...visibilities continue
to remain near 1/2 mile...so I feel more confident about
widespread dense fog continuing in this region at times overnight.

The next evening update is planned for around the normal time of
9 to 930 PM. Brusda

&&

.AVIATION...
UPDATED 2350Z.
Light snow continues to push northward into Southwest MT. Expect
visibilities to generally be 1SM in areas of snow along with
mountains obscured. The snow will spread into the Helena/Bozeman
areas this evening...and then into the Great Falls/Lewistown areas
over night. The snow should move into the Havre area on Wednesday
morning. Areas of dense fog will continue to affect the Cut Bank
area until Wednesday morning. Brusda

&&

.PREV DISCUSSION...
/ISSUED 450 PM MST Tue Dec 16 2014/
Tonight through Thursday...Relatively quiet conditions over
central and north central Montana during the period. Areas of
freezing fog continue to cover portions of north central Montana
this afternoon...and those areas that did burn off will likely
see the fog redevelop late this afternoon or this evening. Have
extended the Freezing Fog Advisory for most of north central
Montana until 11 a.m. Wednesday.

Upper air pattern shows a high pressure ridge over the Rocky
Mountain states with a low pressure trough over the west coast.
Idiosyncrasies in the pattern are resulting in a split flow aloft
over southwest and central Montana...and small weather systems
embedded in the flow, and being steered into Montana, are being
sheared apart and weakened. Best chance for snow from these
systems will be over the southwest Montana mountains. Probabilities
decrease to only slight chances as the system moves to the
northeast over central Montana. As the high pressure ridge shifts
east and the trough begins to move inland, another system will
approach the area during the day Thursday. This again brings slight
chances for snow mainly over the west and southwest mountains.
Temperatures will remain near seasonal averages for this time of
year.

Thursday Night through Tuesday...A weak upper level ridge of high
pressure will keep the forecast area mostly dry Thursday night and
Friday. A shortwave trough will then move into the area Friday
night into Saturday, bringing an increased chance of mountain
snow. However, breezy westerly downslope winds will keep the
plains dry. The weather pattern will change somewhat beginning on
Sunday. An upper level ridge of high pressure will strengthen off
the California coast and an upper level trough of low pressure
will deepen from Hudson Bay into the Great Lakes. This will put
Montana under the influence of a strong northwesterly flow aloft.
The strongest winds aloft (60 to 70 kt at 700 mb) will occur
Sunday into Monday with the passage of a disturbance embedded in
the flow. This set- up will bring gusty westerly downslope winds
to much of the area, but especially over the plains of north
central Montana. In fact, some areas along the Rocky Mountain
Front could approach High Wind criteria (40 mph sustained/58 mph
gusts). Confidence is increasing that High Wind highlights may be
needed for this event. There is also significant moisture with
this disturbance, so have increased the chance for precipitation
out onto the plains. Although the winds will decrease somewhat
after the passage of the disturbance, the northwesterly flow aloft
will remain fairly moist, so have kept the chance for
precipitation above climatological normals across the area into
Tuesday. The breezy winds throughout the period will keep
temperatures around 10 degrees above normal. The warmest day of
the period appears to be Monday, when most lower elevation
locations should get well into the 40s. Coulston

&&

.PRELIMINARY POINT TEMPS/POPS...
GTF  21  37  25  37 /  60  30  10  10
CTB  17  34  22  36 /  10  10  10  10
HLN  20  31  18  33 /  80  20  10  20
BZN  22  31  14  30 /  90  20  10  20
WEY  22  31  17  28 / 100  40  20  30
DLN  20  33  17  33 / 100  20  10  20
HVR  15  31  19  35 /   0  30  20  10
LWT  21  38  22  39 /  60  40  10  10

&&

.TFX WATCHES/WARNINGS/ADVISORIES...
FREEZING FOG ADVISORY until 11 AM MST Wednesday Cascade...
Eastern Glacier...Eastern Pondera...Eastern Teton...Judith
Basin...Northern Rocky Mountain Front...Southern Rocky Mountain
Front...Toole.

&&

$$

weather.gov/greatfalls
www.twitter.com/NWSGreatFalls
www.facebook.com/NWSGreatFalls




000
FXUS65 KTFX 170054
AFDTFX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREAT FALLS MT
554 PM MST Tue Dec 16 2014

.UPDATE...
Updated evening forecast to increase the chances for snow tonight
for Southwest and Central Montana. Overall a swath of snow will
move through the Dillon/Bozeman and Townsend areas this
evening...and then spread into the Helena/Great Falls/Lewistown
area late this evening and overnight. In the Havre area...if the
system holds together...the snow should move up into this region
generally after 4 am. Overall snow accumulations will generally be
around 1/2 inch...but there will be a few areas that get around an
inch of snow.

In terms of fog...with increasing clouds and precip chances...the
threat for widespread dense freezing fog redeveloping in the Great
Falls/Stanford areas is diminishing. If the fog does not redevelop
in the next few hours...this portion might be dropped from the
advisory. However...in the Cut Bank area...visibilities continue
to remain near 1/2 mile...so I feel more confident about
widespread dense fog continuing in this region at times overnight.

The next evening update is planned for around the normal time of
9 to 930 PM. Brusda

&&

.AVIATION...
UPDATED 2350Z.
Light snow continues to push northward into Southwest MT. Expect
visibilities to generally be 1SM in areas of snow along with
mountains obscured. The snow will spread into the Helena/Bozeman
areas this evening...and then into the Great Falls/Lewistown areas
over night. The snow should move into the Havre area on Wednesday
morning. Areas of dense fog will continue to affect the Cut Bank
area until Wednesday morning. Brusda

&&

.PREV DISCUSSION...
/ISSUED 450 PM MST Tue Dec 16 2014/
Tonight through Thursday...Relatively quiet conditions over
central and north central Montana during the period. Areas of
freezing fog continue to cover portions of north central Montana
this afternoon...and those areas that did burn off will likely
see the fog redevelop late this afternoon or this evening. Have
extended the Freezing Fog Advisory for most of north central
Montana until 11 a.m. Wednesday.

Upper air pattern shows a high pressure ridge over the Rocky
Mountain states with a low pressure trough over the west coast.
Idiosyncrasies in the pattern are resulting in a split flow aloft
over southwest and central Montana...and small weather systems
embedded in the flow, and being steered into Montana, are being
sheared apart and weakened. Best chance for snow from these
systems will be over the southwest Montana mountains. Probabilities
decrease to only slight chances as the system moves to the
northeast over central Montana. As the high pressure ridge shifts
east and the trough begins to move inland, another system will
approach the area during the day Thursday. This again brings slight
chances for snow mainly over the west and southwest mountains.
Temperatures will remain near seasonal averages for this time of
year.

Thursday Night through Tuesday...A weak upper level ridge of high
pressure will keep the forecast area mostly dry Thursday night and
Friday. A shortwave trough will then move into the area Friday
night into Saturday, bringing an increased chance of mountain
snow. However, breezy westerly downslope winds will keep the
plains dry. The weather pattern will change somewhat beginning on
Sunday. An upper level ridge of high pressure will strengthen off
the California coast and an upper level trough of low pressure
will deepen from Hudson Bay into the Great Lakes. This will put
Montana under the influence of a strong northwesterly flow aloft.
The strongest winds aloft (60 to 70 kt at 700 mb) will occur
Sunday into Monday with the passage of a disturbance embedded in
the flow. This set- up will bring gusty westerly downslope winds
to much of the area, but especially over the plains of north
central Montana. In fact, some areas along the Rocky Mountain
Front could approach High Wind criteria (40 mph sustained/58 mph
gusts). Confidence is increasing that High Wind highlights may be
needed for this event. There is also significant moisture with
this disturbance, so have increased the chance for precipitation
out onto the plains. Although the winds will decrease somewhat
after the passage of the disturbance, the northwesterly flow aloft
will remain fairly moist, so have kept the chance for
precipitation above climatological normals across the area into
Tuesday. The breezy winds throughout the period will keep
temperatures around 10 degrees above normal. The warmest day of
the period appears to be Monday, when most lower elevation
locations should get well into the 40s. Coulston

&&

.PRELIMINARY POINT TEMPS/POPS...
GTF  21  37  25  37 /  60  30  10  10
CTB  17  34  22  36 /  10  10  10  10
HLN  20  31  18  33 /  80  20  10  20
BZN  22  31  14  30 /  90  20  10  20
WEY  22  31  17  28 / 100  40  20  30
DLN  20  33  17  33 / 100  20  10  20
HVR  15  31  19  35 /   0  30  20  10
LWT  21  38  22  39 /  60  40  10  10

&&

.TFX WATCHES/WARNINGS/ADVISORIES...
FREEZING FOG ADVISORY until 11 AM MST Wednesday Cascade...
Eastern Glacier...Eastern Pondera...Eastern Teton...Judith
Basin...Northern Rocky Mountain Front...Southern Rocky Mountain
Front...Toole.

&&

$$

weather.gov/greatfalls
www.twitter.com/NWSGreatFalls
www.facebook.com/NWSGreatFalls





000
FXUS65 KTFX 162354
AFDTFX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREAT FALLS MT
450 PM MST Tue Dec 16 2014

Aviation Section Updated

.DISCUSSION...
Tonight through Thursday...Relatively quiet conditions over
central and north central Montana during the period. Areas of
freezing fog continue to cover portions of north central Montana
this afternoon...and those areas that did burn off will likely
see the fog redevelop late this afternoon or this evening. Have
extended the Freezing Fog Advisory for most of north central
Montana until 11 a.m. Wednesday.

Upper air pattern shows a high pressure ridge over the Rocky
Mountain states with a low pressure trough over the west coast.
Idiosyncrasies in the pattern are resulting in a split flow aloft
over southwest and central Montana...and small weather systems
embedded in the flow, and being steered into Montana, are being
sheared apart and weakened. Best chance for snow from these
systems will be over the southwest Montana mountains. Probabilities
decrease to only slight chances as the system moves to the
northeast over central Montana. As the high pressure ridge shifts
east and the trough begins to move inland, another system will
approach the area during the day Thursday. This again brings slight
chances for snow mainly over the west and southwest mountains.
Temperatures will remain near seasonal averages for this time of
year.

Thursday Night through Tuesday...A weak upper level ridge of high
pressure will keep the forecast area mostly dry Thursday night and
Friday. A shortwave trough will then move into the area Friday
night into Saturday, bringing an increased chance of mountain
snow. However, breezy westerly downslope winds will keep the
plains dry. The weather pattern will change somewhat beginning on
Sunday. An upper level ridge of high pressure will strengthen off
the California coast and an upper level trough of low pressure
will deepen from Hudson Bay into the Great Lakes. This will put
Montana under the influence of a strong northwesterly flow aloft.
The strongest winds aloft (60 to 70 kt at 700 mb) will occur
Sunday into Monday with the passage of a disturbance embedded in
the flow. This set- up will bring gusty westerly downslope winds
to much of the area, but especially over the plains of north
central Montana. In fact, some areas along the Rocky Mountain
Front could approach High Wind criteria (40 mph sustained/58 mph
gusts). Confidence is increasing that High Wind highlights may be
needed for this event. There is also significant moisture with
this disturbance, so have increased the chance for precipitation
out onto the plains. Although the winds will decrease somewhat
after the passage of the disturbance, the northwesterly flow aloft
will remain fairly moist, so have kept the chance for
precipitation above climatological normals across the area into
Tuesday. The breezy winds throughout the period will keep
temperatures around 10 degrees above normal. The warmest day of
the period appears to be Monday, when most lower elevation
locations should get well into the 40s. Coulston

&&

.AVIATION...
UPDATED 2350Z.
Light snow continues to push northward into Southwest MT. Expect
visibilities to generally be 1SM in areas of snow along with
mountains obscured. The snow will spread into the Helena/Bozeman
areas this evening...and then into the Great Falls/Lewistown areas
over night. The snow should move into the Havre area on Wednesday
morning. Areas of dense fog will continue to affect the Cut Bank
area until Wednesday morning. Brusda

&&

.PRELIMINARY POINT TEMPS/POPS...
GTF  21  37  25  37 /  20  30  10  10
CTB  17  34  22  36 /  10  20  10  10
HLN  20  31  18  33 /  30  20  10  20
BZN  22  31  14  30 /  30  30  10  20
WEY  22  31  17  28 /  50  40  20  30
DLN  20  33  17  33 /  30  20  10  20
HVR  15  31  19  35 /  10  20  20  10
LWT  21  38  22  39 /  20  20  10  10

&&

.TFX WATCHES/WARNINGS/ADVISORIES...
FREEZING FOG ADVISORY until 11 AM MST Wednesday Cascade...
Eastern Glacier...Eastern Pondera...Eastern Teton...Judith
Basin...Northern Rocky Mountain Front...Southern Rocky Mountain
Front...Toole.

&&

$$

weather.gov/greatfalls
www.twitter.com/NWSGreatFalls
www.facebook.com/NWSGreatFalls





000
FXUS65 KTFX 162354
AFDTFX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREAT FALLS MT
450 PM MST Tue Dec 16 2014

Aviation Section Updated

.DISCUSSION...
Tonight through Thursday...Relatively quiet conditions over
central and north central Montana during the period. Areas of
freezing fog continue to cover portions of north central Montana
this afternoon...and those areas that did burn off will likely
see the fog redevelop late this afternoon or this evening. Have
extended the Freezing Fog Advisory for most of north central
Montana until 11 a.m. Wednesday.

Upper air pattern shows a high pressure ridge over the Rocky
Mountain states with a low pressure trough over the west coast.
Idiosyncrasies in the pattern are resulting in a split flow aloft
over southwest and central Montana...and small weather systems
embedded in the flow, and being steered into Montana, are being
sheared apart and weakened. Best chance for snow from these
systems will be over the southwest Montana mountains. Probabilities
decrease to only slight chances as the system moves to the
northeast over central Montana. As the high pressure ridge shifts
east and the trough begins to move inland, another system will
approach the area during the day Thursday. This again brings slight
chances for snow mainly over the west and southwest mountains.
Temperatures will remain near seasonal averages for this time of
year.

Thursday Night through Tuesday...A weak upper level ridge of high
pressure will keep the forecast area mostly dry Thursday night and
Friday. A shortwave trough will then move into the area Friday
night into Saturday, bringing an increased chance of mountain
snow. However, breezy westerly downslope winds will keep the
plains dry. The weather pattern will change somewhat beginning on
Sunday. An upper level ridge of high pressure will strengthen off
the California coast and an upper level trough of low pressure
will deepen from Hudson Bay into the Great Lakes. This will put
Montana under the influence of a strong northwesterly flow aloft.
The strongest winds aloft (60 to 70 kt at 700 mb) will occur
Sunday into Monday with the passage of a disturbance embedded in
the flow. This set- up will bring gusty westerly downslope winds
to much of the area, but especially over the plains of north
central Montana. In fact, some areas along the Rocky Mountain
Front could approach High Wind criteria (40 mph sustained/58 mph
gusts). Confidence is increasing that High Wind highlights may be
needed for this event. There is also significant moisture with
this disturbance, so have increased the chance for precipitation
out onto the plains. Although the winds will decrease somewhat
after the passage of the disturbance, the northwesterly flow aloft
will remain fairly moist, so have kept the chance for
precipitation above climatological normals across the area into
Tuesday. The breezy winds throughout the period will keep
temperatures around 10 degrees above normal. The warmest day of
the period appears to be Monday, when most lower elevation
locations should get well into the 40s. Coulston

&&

.AVIATION...
UPDATED 2350Z.
Light snow continues to push northward into Southwest MT. Expect
visibilities to generally be 1SM in areas of snow along with
mountains obscured. The snow will spread into the Helena/Bozeman
areas this evening...and then into the Great Falls/Lewistown areas
over night. The snow should move into the Havre area on Wednesday
morning. Areas of dense fog will continue to affect the Cut Bank
area until Wednesday morning. Brusda

&&

.PRELIMINARY POINT TEMPS/POPS...
GTF  21  37  25  37 /  20  30  10  10
CTB  17  34  22  36 /  10  20  10  10
HLN  20  31  18  33 /  30  20  10  20
BZN  22  31  14  30 /  30  30  10  20
WEY  22  31  17  28 /  50  40  20  30
DLN  20  33  17  33 /  30  20  10  20
HVR  15  31  19  35 /  10  20  20  10
LWT  21  38  22  39 /  20  20  10  10

&&

.TFX WATCHES/WARNINGS/ADVISORIES...
FREEZING FOG ADVISORY until 11 AM MST Wednesday Cascade...
Eastern Glacier...Eastern Pondera...Eastern Teton...Judith
Basin...Northern Rocky Mountain Front...Southern Rocky Mountain
Front...Toole.

&&

$$

weather.gov/greatfalls
www.twitter.com/NWSGreatFalls
www.facebook.com/NWSGreatFalls





000
FXUS65 KTFX 162354
AFDTFX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREAT FALLS MT
450 PM MST Tue Dec 16 2014

Aviation Section Updated

.DISCUSSION...
Tonight through Thursday...Relatively quiet conditions over
central and north central Montana during the period. Areas of
freezing fog continue to cover portions of north central Montana
this afternoon...and those areas that did burn off will likely
see the fog redevelop late this afternoon or this evening. Have
extended the Freezing Fog Advisory for most of north central
Montana until 11 a.m. Wednesday.

Upper air pattern shows a high pressure ridge over the Rocky
Mountain states with a low pressure trough over the west coast.
Idiosyncrasies in the pattern are resulting in a split flow aloft
over southwest and central Montana...and small weather systems
embedded in the flow, and being steered into Montana, are being
sheared apart and weakened. Best chance for snow from these
systems will be over the southwest Montana mountains. Probabilities
decrease to only slight chances as the system moves to the
northeast over central Montana. As the high pressure ridge shifts
east and the trough begins to move inland, another system will
approach the area during the day Thursday. This again brings slight
chances for snow mainly over the west and southwest mountains.
Temperatures will remain near seasonal averages for this time of
year.

Thursday Night through Tuesday...A weak upper level ridge of high
pressure will keep the forecast area mostly dry Thursday night and
Friday. A shortwave trough will then move into the area Friday
night into Saturday, bringing an increased chance of mountain
snow. However, breezy westerly downslope winds will keep the
plains dry. The weather pattern will change somewhat beginning on
Sunday. An upper level ridge of high pressure will strengthen off
the California coast and an upper level trough of low pressure
will deepen from Hudson Bay into the Great Lakes. This will put
Montana under the influence of a strong northwesterly flow aloft.
The strongest winds aloft (60 to 70 kt at 700 mb) will occur
Sunday into Monday with the passage of a disturbance embedded in
the flow. This set- up will bring gusty westerly downslope winds
to much of the area, but especially over the plains of north
central Montana. In fact, some areas along the Rocky Mountain
Front could approach High Wind criteria (40 mph sustained/58 mph
gusts). Confidence is increasing that High Wind highlights may be
needed for this event. There is also significant moisture with
this disturbance, so have increased the chance for precipitation
out onto the plains. Although the winds will decrease somewhat
after the passage of the disturbance, the northwesterly flow aloft
will remain fairly moist, so have kept the chance for
precipitation above climatological normals across the area into
Tuesday. The breezy winds throughout the period will keep
temperatures around 10 degrees above normal. The warmest day of
the period appears to be Monday, when most lower elevation
locations should get well into the 40s. Coulston

&&

.AVIATION...
UPDATED 2350Z.
Light snow continues to push northward into Southwest MT. Expect
visibilities to generally be 1SM in areas of snow along with
mountains obscured. The snow will spread into the Helena/Bozeman
areas this evening...and then into the Great Falls/Lewistown areas
over night. The snow should move into the Havre area on Wednesday
morning. Areas of dense fog will continue to affect the Cut Bank
area until Wednesday morning. Brusda

&&

.PRELIMINARY POINT TEMPS/POPS...
GTF  21  37  25  37 /  20  30  10  10
CTB  17  34  22  36 /  10  20  10  10
HLN  20  31  18  33 /  30  20  10  20
BZN  22  31  14  30 /  30  30  10  20
WEY  22  31  17  28 /  50  40  20  30
DLN  20  33  17  33 /  30  20  10  20
HVR  15  31  19  35 /  10  20  20  10
LWT  21  38  22  39 /  20  20  10  10

&&

.TFX WATCHES/WARNINGS/ADVISORIES...
FREEZING FOG ADVISORY until 11 AM MST Wednesday Cascade...
Eastern Glacier...Eastern Pondera...Eastern Teton...Judith
Basin...Northern Rocky Mountain Front...Southern Rocky Mountain
Front...Toole.

&&

$$

weather.gov/greatfalls
www.twitter.com/NWSGreatFalls
www.facebook.com/NWSGreatFalls





000
FXUS65 KTFX 162354
AFDTFX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREAT FALLS MT
450 PM MST Tue Dec 16 2014

Aviation Section Updated

.DISCUSSION...
Tonight through Thursday...Relatively quiet conditions over
central and north central Montana during the period. Areas of
freezing fog continue to cover portions of north central Montana
this afternoon...and those areas that did burn off will likely
see the fog redevelop late this afternoon or this evening. Have
extended the Freezing Fog Advisory for most of north central
Montana until 11 a.m. Wednesday.

Upper air pattern shows a high pressure ridge over the Rocky
Mountain states with a low pressure trough over the west coast.
Idiosyncrasies in the pattern are resulting in a split flow aloft
over southwest and central Montana...and small weather systems
embedded in the flow, and being steered into Montana, are being
sheared apart and weakened. Best chance for snow from these
systems will be over the southwest Montana mountains. Probabilities
decrease to only slight chances as the system moves to the
northeast over central Montana. As the high pressure ridge shifts
east and the trough begins to move inland, another system will
approach the area during the day Thursday. This again brings slight
chances for snow mainly over the west and southwest mountains.
Temperatures will remain near seasonal averages for this time of
year.

Thursday Night through Tuesday...A weak upper level ridge of high
pressure will keep the forecast area mostly dry Thursday night and
Friday. A shortwave trough will then move into the area Friday
night into Saturday, bringing an increased chance of mountain
snow. However, breezy westerly downslope winds will keep the
plains dry. The weather pattern will change somewhat beginning on
Sunday. An upper level ridge of high pressure will strengthen off
the California coast and an upper level trough of low pressure
will deepen from Hudson Bay into the Great Lakes. This will put
Montana under the influence of a strong northwesterly flow aloft.
The strongest winds aloft (60 to 70 kt at 700 mb) will occur
Sunday into Monday with the passage of a disturbance embedded in
the flow. This set- up will bring gusty westerly downslope winds
to much of the area, but especially over the plains of north
central Montana. In fact, some areas along the Rocky Mountain
Front could approach High Wind criteria (40 mph sustained/58 mph
gusts). Confidence is increasing that High Wind highlights may be
needed for this event. There is also significant moisture with
this disturbance, so have increased the chance for precipitation
out onto the plains. Although the winds will decrease somewhat
after the passage of the disturbance, the northwesterly flow aloft
will remain fairly moist, so have kept the chance for
precipitation above climatological normals across the area into
Tuesday. The breezy winds throughout the period will keep
temperatures around 10 degrees above normal. The warmest day of
the period appears to be Monday, when most lower elevation
locations should get well into the 40s. Coulston

&&

.AVIATION...
UPDATED 2350Z.
Light snow continues to push northward into Southwest MT. Expect
visibilities to generally be 1SM in areas of snow along with
mountains obscured. The snow will spread into the Helena/Bozeman
areas this evening...and then into the Great Falls/Lewistown areas
over night. The snow should move into the Havre area on Wednesday
morning. Areas of dense fog will continue to affect the Cut Bank
area until Wednesday morning. Brusda

&&

.PRELIMINARY POINT TEMPS/POPS...
GTF  21  37  25  37 /  20  30  10  10
CTB  17  34  22  36 /  10  20  10  10
HLN  20  31  18  33 /  30  20  10  20
BZN  22  31  14  30 /  30  30  10  20
WEY  22  31  17  28 /  50  40  20  30
DLN  20  33  17  33 /  30  20  10  20
HVR  15  31  19  35 /  10  20  20  10
LWT  21  38  22  39 /  20  20  10  10

&&

.TFX WATCHES/WARNINGS/ADVISORIES...
FREEZING FOG ADVISORY until 11 AM MST Wednesday Cascade...
Eastern Glacier...Eastern Pondera...Eastern Teton...Judith
Basin...Northern Rocky Mountain Front...Southern Rocky Mountain
Front...Toole.

&&

$$

weather.gov/greatfalls
www.twitter.com/NWSGreatFalls
www.facebook.com/NWSGreatFalls





000
FXUS65 KTFX 162155
AFDTFX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREAT FALLS MT
255 PM MST Tue Dec 16 2014

.DISCUSSION...
Tonight through Thursday...Relatively quiet conditions over
central and north central Montana during the period. Areas of
freezing fog continue to cover portions of north central Montana
this afternoon...and those areas that did burn off will likely
see the fog redevelop late this afternoon or this evening. Have
extended the Freezing Fog Advisory for most of north central
Montana until 11 a.m. Wednesday.

Upper air pattern shows a high pressure ridge over the Rocky
Mountain states with a low pressure trough over the west coast.
Idiosyncrasies in the pattern are resulting in a split flow aloft
over southwest and central Montana...and small weather systems
embedded in the flow, and being steered into Montana, are being
sheared apart and weakened. Best chance for snow from these
systems will be over the southwest Montana mountains. Probabilities
decrease to only slight chances as the system moves to the
northeast over central Montana. As the high pressure ridge shifts
east and the trough begins to move inland, another system will
approach the area during the day Thursday. This again brings slight
chances for snow mainly over the west and southwest mountains.
Temperatures will remain near seasonal averages for this time of
year.

Thursday Night through Tuesday...A weak upper level ridge of high
pressure will keep the forecast area mostly dry Thursday night and
Friday. A shortwave trough will then move into the area Friday
night into Saturday, bringing an increased chance of mountain
snow. However, breezy westerly downslope winds will keep the
plains dry. The weather pattern will change somewhat beginning on
Sunday. An upper level ridge of high pressure will strengthen off
the California coast and an upper level trough of low pressure
will deepen from Hudson Bay into the Great Lakes. This will put
Montana under the influence of a strong northwesterly flow aloft.
The strongest winds aloft (60 to 70 kt at 700 mb) will occur
Sunday into Monday with the passage of a disturbance embedded in
the flow. This set- up will bring gusty westerly downslope winds
to much of the area, but especially over the plains of north
central Montana. In fact, some areas along the Rocky Mountain
Front could approach High Wind criteria (40 mph sustained/58 mph
gusts). Confidence is increasing that High Wind highlights may be
needed for this event. There is also significant moisture with
this disturbance, so have increased the chance for precipitation
out onto the plains. Although the winds will decrease somewhat
after the passage of the disturbance, the northwesterly flow aloft
will remain fairly moist, so have kept the chance for
precipitation above climatological normals across the area into
Tuesday. The breezy winds throughout the period will keep
temperatures around 10 degrees above normal. The warmest day of
the period appears to be Monday, when most lower elevation
locations should get well into the 40s. Coulston

&&

.AVIATION...
UPDATED 1750Z.
This is a very low confidence forecast with respect to ceilings and
visibilities. Do have fair confidence that areas of light snow will
spread into southwest Montana late this afternoon then reach the
Canadian border early Wednesday morning. Conditions for KGTF and
KCTB and KHVR could range from VFR to LIFR at anytime at least into
early Wednesday morning. Then for KBZN and KHLN and KLWT conditions
could range from VFR to IFR at any time after 00Z. Also have fair
confidence that conditions will be mostly VFR at 18Z Wednesday. Blank

&&

.PRELIMINARY POINT TEMPS/POPS...
GTF  21  37  25  37 /  20  30  10  10
CTB  17  34  22  36 /  10  20  10  10
HLN  20  31  18  33 /  30  20  10  20
BZN  22  31  14  30 /  30  30  10  20
WEY  22  31  17  28 /  50  40  20  30
DLN  20  33  17  33 /  30  20  10  20
HVR  15  31  19  35 /  10  20  20  10
LWT  21  38  22  39 /  20  20  10  10

&&

.TFX WATCHES/WARNINGS/ADVISORIES...
FREEZING FOG ADVISORY until 11 AM MST Wednesday Cascade...
Eastern Glacier...Eastern Pondera...Eastern Teton...Judith
Basin...Northern Rocky Mountain Front...Southern Rocky Mountain
Front...Toole.

&&

$$

weather.gov/greatfalls
www.twitter.com/NWSGreatFalls
www.facebook.com/NWSGreatFalls






000
FXUS65 KTFX 162155
AFDTFX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREAT FALLS MT
255 PM MST Tue Dec 16 2014

.DISCUSSION...
Tonight through Thursday...Relatively quiet conditions over
central and north central Montana during the period. Areas of
freezing fog continue to cover portions of north central Montana
this afternoon...and those areas that did burn off will likely
see the fog redevelop late this afternoon or this evening. Have
extended the Freezing Fog Advisory for most of north central
Montana until 11 a.m. Wednesday.

Upper air pattern shows a high pressure ridge over the Rocky
Mountain states with a low pressure trough over the west coast.
Idiosyncrasies in the pattern are resulting in a split flow aloft
over southwest and central Montana...and small weather systems
embedded in the flow, and being steered into Montana, are being
sheared apart and weakened. Best chance for snow from these
systems will be over the southwest Montana mountains. Probabilities
decrease to only slight chances as the system moves to the
northeast over central Montana. As the high pressure ridge shifts
east and the trough begins to move inland, another system will
approach the area during the day Thursday. This again brings slight
chances for snow mainly over the west and southwest mountains.
Temperatures will remain near seasonal averages for this time of
year.

Thursday Night through Tuesday...A weak upper level ridge of high
pressure will keep the forecast area mostly dry Thursday night and
Friday. A shortwave trough will then move into the area Friday
night into Saturday, bringing an increased chance of mountain
snow. However, breezy westerly downslope winds will keep the
plains dry. The weather pattern will change somewhat beginning on
Sunday. An upper level ridge of high pressure will strengthen off
the California coast and an upper level trough of low pressure
will deepen from Hudson Bay into the Great Lakes. This will put
Montana under the influence of a strong northwesterly flow aloft.
The strongest winds aloft (60 to 70 kt at 700 mb) will occur
Sunday into Monday with the passage of a disturbance embedded in
the flow. This set- up will bring gusty westerly downslope winds
to much of the area, but especially over the plains of north
central Montana. In fact, some areas along the Rocky Mountain
Front could approach High Wind criteria (40 mph sustained/58 mph
gusts). Confidence is increasing that High Wind highlights may be
needed for this event. There is also significant moisture with
this disturbance, so have increased the chance for precipitation
out onto the plains. Although the winds will decrease somewhat
after the passage of the disturbance, the northwesterly flow aloft
will remain fairly moist, so have kept the chance for
precipitation above climatological normals across the area into
Tuesday. The breezy winds throughout the period will keep
temperatures around 10 degrees above normal. The warmest day of
the period appears to be Monday, when most lower elevation
locations should get well into the 40s. Coulston

&&

.AVIATION...
UPDATED 1750Z.
This is a very low confidence forecast with respect to ceilings and
visibilities. Do have fair confidence that areas of light snow will
spread into southwest Montana late this afternoon then reach the
Canadian border early Wednesday morning. Conditions for KGTF and
KCTB and KHVR could range from VFR to LIFR at anytime at least into
early Wednesday morning. Then for KBZN and KHLN and KLWT conditions
could range from VFR to IFR at any time after 00Z. Also have fair
confidence that conditions will be mostly VFR at 18Z Wednesday. Blank

&&

.PRELIMINARY POINT TEMPS/POPS...
GTF  21  37  25  37 /  20  30  10  10
CTB  17  34  22  36 /  10  20  10  10
HLN  20  31  18  33 /  30  20  10  20
BZN  22  31  14  30 /  30  30  10  20
WEY  22  31  17  28 /  50  40  20  30
DLN  20  33  17  33 /  30  20  10  20
HVR  15  31  19  35 /  10  20  20  10
LWT  21  38  22  39 /  20  20  10  10

&&

.TFX WATCHES/WARNINGS/ADVISORIES...
FREEZING FOG ADVISORY until 11 AM MST Wednesday Cascade...
Eastern Glacier...Eastern Pondera...Eastern Teton...Judith
Basin...Northern Rocky Mountain Front...Southern Rocky Mountain
Front...Toole.

&&

$$

weather.gov/greatfalls
www.twitter.com/NWSGreatFalls
www.facebook.com/NWSGreatFalls






000
FXUS65 KTFX 162155
AFDTFX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREAT FALLS MT
255 PM MST Tue Dec 16 2014

.DISCUSSION...
Tonight through Thursday...Relatively quiet conditions over
central and north central Montana during the period. Areas of
freezing fog continue to cover portions of north central Montana
this afternoon...and those areas that did burn off will likely
see the fog redevelop late this afternoon or this evening. Have
extended the Freezing Fog Advisory for most of north central
Montana until 11 a.m. Wednesday.

Upper air pattern shows a high pressure ridge over the Rocky
Mountain states with a low pressure trough over the west coast.
Idiosyncrasies in the pattern are resulting in a split flow aloft
over southwest and central Montana...and small weather systems
embedded in the flow, and being steered into Montana, are being
sheared apart and weakened. Best chance for snow from these
systems will be over the southwest Montana mountains. Probabilities
decrease to only slight chances as the system moves to the
northeast over central Montana. As the high pressure ridge shifts
east and the trough begins to move inland, another system will
approach the area during the day Thursday. This again brings slight
chances for snow mainly over the west and southwest mountains.
Temperatures will remain near seasonal averages for this time of
year.

Thursday Night through Tuesday...A weak upper level ridge of high
pressure will keep the forecast area mostly dry Thursday night and
Friday. A shortwave trough will then move into the area Friday
night into Saturday, bringing an increased chance of mountain
snow. However, breezy westerly downslope winds will keep the
plains dry. The weather pattern will change somewhat beginning on
Sunday. An upper level ridge of high pressure will strengthen off
the California coast and an upper level trough of low pressure
will deepen from Hudson Bay into the Great Lakes. This will put
Montana under the influence of a strong northwesterly flow aloft.
The strongest winds aloft (60 to 70 kt at 700 mb) will occur
Sunday into Monday with the passage of a disturbance embedded in
the flow. This set- up will bring gusty westerly downslope winds
to much of the area, but especially over the plains of north
central Montana. In fact, some areas along the Rocky Mountain
Front could approach High Wind criteria (40 mph sustained/58 mph
gusts). Confidence is increasing that High Wind highlights may be
needed for this event. There is also significant moisture with
this disturbance, so have increased the chance for precipitation
out onto the plains. Although the winds will decrease somewhat
after the passage of the disturbance, the northwesterly flow aloft
will remain fairly moist, so have kept the chance for
precipitation above climatological normals across the area into
Tuesday. The breezy winds throughout the period will keep
temperatures around 10 degrees above normal. The warmest day of
the period appears to be Monday, when most lower elevation
locations should get well into the 40s. Coulston

&&

.AVIATION...
UPDATED 1750Z.
This is a very low confidence forecast with respect to ceilings and
visibilities. Do have fair confidence that areas of light snow will
spread into southwest Montana late this afternoon then reach the
Canadian border early Wednesday morning. Conditions for KGTF and
KCTB and KHVR could range from VFR to LIFR at anytime at least into
early Wednesday morning. Then for KBZN and KHLN and KLWT conditions
could range from VFR to IFR at any time after 00Z. Also have fair
confidence that conditions will be mostly VFR at 18Z Wednesday. Blank

&&

.PRELIMINARY POINT TEMPS/POPS...
GTF  21  37  25  37 /  20  30  10  10
CTB  17  34  22  36 /  10  20  10  10
HLN  20  31  18  33 /  30  20  10  20
BZN  22  31  14  30 /  30  30  10  20
WEY  22  31  17  28 /  50  40  20  30
DLN  20  33  17  33 /  30  20  10  20
HVR  15  31  19  35 /  10  20  20  10
LWT  21  38  22  39 /  20  20  10  10

&&

.TFX WATCHES/WARNINGS/ADVISORIES...
FREEZING FOG ADVISORY until 11 AM MST Wednesday Cascade...
Eastern Glacier...Eastern Pondera...Eastern Teton...Judith
Basin...Northern Rocky Mountain Front...Southern Rocky Mountain
Front...Toole.

&&

$$

weather.gov/greatfalls
www.twitter.com/NWSGreatFalls
www.facebook.com/NWSGreatFalls






000
FXUS65 KTFX 162155
AFDTFX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREAT FALLS MT
255 PM MST Tue Dec 16 2014

.DISCUSSION...
Tonight through Thursday...Relatively quiet conditions over
central and north central Montana during the period. Areas of
freezing fog continue to cover portions of north central Montana
this afternoon...and those areas that did burn off will likely
see the fog redevelop late this afternoon or this evening. Have
extended the Freezing Fog Advisory for most of north central
Montana until 11 a.m. Wednesday.

Upper air pattern shows a high pressure ridge over the Rocky
Mountain states with a low pressure trough over the west coast.
Idiosyncrasies in the pattern are resulting in a split flow aloft
over southwest and central Montana...and small weather systems
embedded in the flow, and being steered into Montana, are being
sheared apart and weakened. Best chance for snow from these
systems will be over the southwest Montana mountains. Probabilities
decrease to only slight chances as the system moves to the
northeast over central Montana. As the high pressure ridge shifts
east and the trough begins to move inland, another system will
approach the area during the day Thursday. This again brings slight
chances for snow mainly over the west and southwest mountains.
Temperatures will remain near seasonal averages for this time of
year.

Thursday Night through Tuesday...A weak upper level ridge of high
pressure will keep the forecast area mostly dry Thursday night and
Friday. A shortwave trough will then move into the area Friday
night into Saturday, bringing an increased chance of mountain
snow. However, breezy westerly downslope winds will keep the
plains dry. The weather pattern will change somewhat beginning on
Sunday. An upper level ridge of high pressure will strengthen off
the California coast and an upper level trough of low pressure
will deepen from Hudson Bay into the Great Lakes. This will put
Montana under the influence of a strong northwesterly flow aloft.
The strongest winds aloft (60 to 70 kt at 700 mb) will occur
Sunday into Monday with the passage of a disturbance embedded in
the flow. This set- up will bring gusty westerly downslope winds
to much of the area, but especially over the plains of north
central Montana. In fact, some areas along the Rocky Mountain
Front could approach High Wind criteria (40 mph sustained/58 mph
gusts). Confidence is increasing that High Wind highlights may be
needed for this event. There is also significant moisture with
this disturbance, so have increased the chance for precipitation
out onto the plains. Although the winds will decrease somewhat
after the passage of the disturbance, the northwesterly flow aloft
will remain fairly moist, so have kept the chance for
precipitation above climatological normals across the area into
Tuesday. The breezy winds throughout the period will keep
temperatures around 10 degrees above normal. The warmest day of
the period appears to be Monday, when most lower elevation
locations should get well into the 40s. Coulston

&&

.AVIATION...
UPDATED 1750Z.
This is a very low confidence forecast with respect to ceilings and
visibilities. Do have fair confidence that areas of light snow will
spread into southwest Montana late this afternoon then reach the
Canadian border early Wednesday morning. Conditions for KGTF and
KCTB and KHVR could range from VFR to LIFR at anytime at least into
early Wednesday morning. Then for KBZN and KHLN and KLWT conditions
could range from VFR to IFR at any time after 00Z. Also have fair
confidence that conditions will be mostly VFR at 18Z Wednesday. Blank

&&

.PRELIMINARY POINT TEMPS/POPS...
GTF  21  37  25  37 /  20  30  10  10
CTB  17  34  22  36 /  10  20  10  10
HLN  20  31  18  33 /  30  20  10  20
BZN  22  31  14  30 /  30  30  10  20
WEY  22  31  17  28 /  50  40  20  30
DLN  20  33  17  33 /  30  20  10  20
HVR  15  31  19  35 /  10  20  20  10
LWT  21  38  22  39 /  20  20  10  10

&&

.TFX WATCHES/WARNINGS/ADVISORIES...
FREEZING FOG ADVISORY until 11 AM MST Wednesday Cascade...
Eastern Glacier...Eastern Pondera...Eastern Teton...Judith
Basin...Northern Rocky Mountain Front...Southern Rocky Mountain
Front...Toole.

&&

$$

weather.gov/greatfalls
www.twitter.com/NWSGreatFalls
www.facebook.com/NWSGreatFalls






000
FXUS65 KMSO 162151
AFDMSO

Area Forecast Discussion
National Weather Service Missoula MT
251 PM MST TUE DEC 16 2014

.DISCUSSION...

Weather across the Northern Rockies through Friday will be
characterized by Pacific storm systems approaching the region and
quickly weakening. The result of this scenario will be gray skies,
occasional light snowfall over mountain passes and high elevation
valleys, however travel impacts will be quite localized.

Beginning Saturday, the Pacific jet stream is anticipated to
return to the Northern Rockies, initiating a prolonged period of
mountain-enhanced precipitation. A surge of subtropical moisture
will accompany the Pacific jet as well, increasing precipitation
potential and snow levels. Snow will impact mountain passes from
time to time through midweek, as wave after wave will pass over
the region. Ridgetop winds will increase significantly Saturday
night as well, allowing falling snow to blow around and load up
onto easterly-facing mountain slopes.

By midweek, increasingly cool air will arrive over the Northern
Rockies, bringing impactful snowfall to both mountain and valley
locations. In fact, many of the global forecast models depict an
arctic outbreak by Thursday. Most models suggest that the most
significant snow portion of this event will take place south of
the region, however blowing snow and very cold wind chill will
still remain an impact. Also consider this: Recently warm road
temperatures will allow new snowfall to melt initially, however
the movement of arctic air over roadways will likely cause them to
freeze over suddenly. Simply put, travel in and around the
Northern Rockies could be significantly impacted around the
Christmas holiday.

&&

.AVIATION...There is high confidence in periods of snow for KBTM
and KSMN this evening. Showers are expected to clear the area
tomorrow morning by 17/1200Z. Low ceilings, terrain obscurations,
and visibility reductions can be expected with the snow showers.
Elsewhere, benign weather is forecast. Mid-level cloud decks and
light winds will continue through tomorrow.

&&

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

$$




000
FXUS65 KMSO 162151
AFDMSO

Area Forecast Discussion
National Weather Service Missoula MT
251 PM MST TUE DEC 16 2014

.DISCUSSION...

Weather across the Northern Rockies through Friday will be
characterized by Pacific storm systems approaching the region and
quickly weakening. The result of this scenario will be gray skies,
occasional light snowfall over mountain passes and high elevation
valleys, however travel impacts will be quite localized.

Beginning Saturday, the Pacific jet stream is anticipated to
return to the Northern Rockies, initiating a prolonged period of
mountain-enhanced precipitation. A surge of subtropical moisture
will accompany the Pacific jet as well, increasing precipitation
potential and snow levels. Snow will impact mountain passes from
time to time through midweek, as wave after wave will pass over
the region. Ridgetop winds will increase significantly Saturday
night as well, allowing falling snow to blow around and load up
onto easterly-facing mountain slopes.

By midweek, increasingly cool air will arrive over the Northern
Rockies, bringing impactful snowfall to both mountain and valley
locations. In fact, many of the global forecast models depict an
arctic outbreak by Thursday. Most models suggest that the most
significant snow portion of this event will take place south of
the region, however blowing snow and very cold wind chill will
still remain an impact. Also consider this: Recently warm road
temperatures will allow new snowfall to melt initially, however
the movement of arctic air over roadways will likely cause them to
freeze over suddenly. Simply put, travel in and around the
Northern Rockies could be significantly impacted around the
Christmas holiday.

&&

.AVIATION...There is high confidence in periods of snow for KBTM
and KSMN this evening. Showers are expected to clear the area
tomorrow morning by 17/1200Z. Low ceilings, terrain obscurations,
and visibility reductions can be expected with the snow showers.
Elsewhere, benign weather is forecast. Mid-level cloud decks and
light winds will continue through tomorrow.

&&

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

$$




000
FXUS65 KMSO 162151
AFDMSO

Area Forecast Discussion
National Weather Service Missoula MT
251 PM MST TUE DEC 16 2014

.DISCUSSION...

Weather across the Northern Rockies through Friday will be
characterized by Pacific storm systems approaching the region and
quickly weakening. The result of this scenario will be gray skies,
occasional light snowfall over mountain passes and high elevation
valleys, however travel impacts will be quite localized.

Beginning Saturday, the Pacific jet stream is anticipated to
return to the Northern Rockies, initiating a prolonged period of
mountain-enhanced precipitation. A surge of subtropical moisture
will accompany the Pacific jet as well, increasing precipitation
potential and snow levels. Snow will impact mountain passes from
time to time through midweek, as wave after wave will pass over
the region. Ridgetop winds will increase significantly Saturday
night as well, allowing falling snow to blow around and load up
onto easterly-facing mountain slopes.

By midweek, increasingly cool air will arrive over the Northern
Rockies, bringing impactful snowfall to both mountain and valley
locations. In fact, many of the global forecast models depict an
arctic outbreak by Thursday. Most models suggest that the most
significant snow portion of this event will take place south of
the region, however blowing snow and very cold wind chill will
still remain an impact. Also consider this: Recently warm road
temperatures will allow new snowfall to melt initially, however
the movement of arctic air over roadways will likely cause them to
freeze over suddenly. Simply put, travel in and around the
Northern Rockies could be significantly impacted around the
Christmas holiday.

&&

.AVIATION...There is high confidence in periods of snow for KBTM
and KSMN this evening. Showers are expected to clear the area
tomorrow morning by 17/1200Z. Low ceilings, terrain obscurations,
and visibility reductions can be expected with the snow showers.
Elsewhere, benign weather is forecast. Mid-level cloud decks and
light winds will continue through tomorrow.

&&

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

$$




000
FXUS65 KMSO 162151
AFDMSO

Area Forecast Discussion
National Weather Service Missoula MT
251 PM MST TUE DEC 16 2014

.DISCUSSION...

Weather across the Northern Rockies through Friday will be
characterized by Pacific storm systems approaching the region and
quickly weakening. The result of this scenario will be gray skies,
occasional light snowfall over mountain passes and high elevation
valleys, however travel impacts will be quite localized.

Beginning Saturday, the Pacific jet stream is anticipated to
return to the Northern Rockies, initiating a prolonged period of
mountain-enhanced precipitation. A surge of subtropical moisture
will accompany the Pacific jet as well, increasing precipitation
potential and snow levels. Snow will impact mountain passes from
time to time through midweek, as wave after wave will pass over
the region. Ridgetop winds will increase significantly Saturday
night as well, allowing falling snow to blow around and load up
onto easterly-facing mountain slopes.

By midweek, increasingly cool air will arrive over the Northern
Rockies, bringing impactful snowfall to both mountain and valley
locations. In fact, many of the global forecast models depict an
arctic outbreak by Thursday. Most models suggest that the most
significant snow portion of this event will take place south of
the region, however blowing snow and very cold wind chill will
still remain an impact. Also consider this: Recently warm road
temperatures will allow new snowfall to melt initially, however
the movement of arctic air over roadways will likely cause them to
freeze over suddenly. Simply put, travel in and around the
Northern Rockies could be significantly impacted around the
Christmas holiday.

&&

.AVIATION...There is high confidence in periods of snow for KBTM
and KSMN this evening. Showers are expected to clear the area
tomorrow morning by 17/1200Z. Low ceilings, terrain obscurations,
and visibility reductions can be expected with the snow showers.
Elsewhere, benign weather is forecast. Mid-level cloud decks and
light winds will continue through tomorrow.

&&

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

$$




000
FXUS65 KBYZ 162123
AFDBYZ

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BILLINGS MT
223 PM MST TUE DEC 16 2014

.SHORT TERM...VALID FOR WED AND THU...

AREAS OF FOG STILL PERSISTING ACROSS PORTIONS OF SC/SE MT THIS
AFTERNOON. MOIST UPSLOPE FLOW OF AIR WITH LIGHT WINDS ALOFT IS
ALLOWING FOG TO CONTINUE OVER THE AREA. VISIBILITY HAS BEEN
IMPROVING OVER OUR WESTERN ZONES LATE THIS AFTERNOON AS A WEAK
DISTURBANCE MOVES TOWARD OUR REGION AND IS SPREADING MID LEVEL
CLOUD DECK ACROSS THE AREA. WILL GO AHEAD AND DROP THE DENSE FOG
ADVISORY FOR OUR WESTERN ZONES WITH IMPROVING VISIBILITIES. HRRR
IS SHOWING MOIST UPSLOPE FLOW TO CONTINUE OVERNIGHT AND FOG WILL
AGAIN BE POSSIBLE OVER MUCH OF OUR FORECAST AREA. MOISTURE NOT
AS DEEP AS THE PREVIOUS NIGHT AND DO NOT EXPECT WIDESPREAD FOG
WITH VISIBILITY BELOW A 1/2 MILE.

UPPER WAVE WILL DRIFT SLOWLY ACROSS THE AREA WEDNESDAY AS 300 MB
JET STAYS WELL SOUTH OF US. WEAK QG FORCING WITH THIS WAVE WILL
BRING SOME LIGHT SNOW TO THE PLAINS TOMORROW BUT NO SNOW
ACCUMULATIONS ARE EXPECTED. DRY WEATHER RETURNING TO THE PLAINS
WEDNESDAY NIGHT THROUGH THURSDAY AS WEAK SHORT WAVE RIDGING
MOVES ACROSS THE REGION. SOME MOUNTAIN SNOW SHOWERS WILL CONTINUE
THROUGH THIS PERIOD BUT AMOUNTS WILL BE LIGHT. WITH INCREASING
HEIGHTS WEDNESDAY AND THURSDAY...TEMPERATURES WILL CLIMB BACK TO
NEAR SEASONAL NORMALS. RICHMOND


.LONG TERM...VALID FOR FRI...SAT...SUN...MON...TUE...

MODELS CONTINUE TO INCREASE CONFIDENCE IN THE EXTENDED. BOTH THE
OPERATIONAL GFS AND ECMWF GENERALLY FIT WITHIN THE SPREAD OF THE
ENSEMBLE DATA. WEAK PACIFIC RIDGE WILL MOVE IN TO THE STATE
FRIDAY. SATURDAY ANOTHER SHORTWAVE WILL MOVE THROUGH...AS THE FLOW
INCREASES AND BECOMES MORE NORTHWESTERLY. PRECIP CHANCES WILL
INCREASE IN THE MOUNTAINS.

SUNDAY WILL SEE SOME LEESIDE TROUGHING DEVELOP. WINDS WILL PICKUP
AROUND NYE AND LIVINGSTON AS THE PRESSURE GRADIENT TIGHTENS DURING
THE DAY SUNDAY. WINDS WILL BEGIN TO INCREASE SUNDAY NIGHT TO AROUND
BILLINGS. FOR MONDAY...IT STILL LOOKS LIKE A COLD FRONT WILL MOVE
THROUGH AS A SURFACE LOW DROPS OUT OF CANADA...BRING PRECIP TO
MUCH OF THE AREA. AS WITH THE PREVIOUS FORECAST...MODELS CONTINUE
TO DEVELOP AN ATMOSPHERIC RIVER...GIVING THE AREA PLENTY OF
MOISTURE. WITH THIS STILL A LONG WAY OFF...HAVE OPTED TO CONTINUE
SIMILAR POPS TO THE PREVIOUS FORECAST. GIVEN THAT TEMPERATURES
WILL STILL BE WARM...LOOKS LIKE MUCH OF THE CENTRAL ZONES WILL
SEE RAIN THAT WILL SWITCH TO SNOW AS TEMPERATURES DROP MONDAY
NIGHT. REIMER
&&

.AVIATION...

LIFR TO MVFR CONDITIONS WILL PERSIST THROUGH THE AFTERNOON AND
OVERNIGHT. AS TEMPERATURES DROP A LITTLE AFTER SUNSET...SOME
LOCATIONS MAY SEE SOME LOWER CEILINGS AND VISIBILITIES DEVELOP
AGAIN. THINGS LOOK TO IMPROVE SOME DURING THE DAY TOMORROW.
MOUNTAIN OBSCURATIONS WILL BE WIDESPREAD THROUGH TONIGHT. REIMER

&&

.PRELIMINARY POINT TEMP/POPS...

    WED     THU     FRI     SAT     SUN     MON     TUE
-----------------------------------------------------------
BIL 020/036 022/039 023/038 027/042 026/044 035/047 030/041
    11/E    01/B    10/U    11/B    13/W    34/W    33/W
LVM 024/040 023/042 023/040 026/043 026/044 036/047 030/043
    22/J    11/E    11/B    11/N    13/W    33/W    33/W
HDN 014/032 015/037 016/037 020/040 019/041 029/044 026/040
    01/E    01/B    10/U    01/B    12/W    33/W    33/W
MLS 014/029 016/036 019/037 019/039 022/041 030/043 026/039
    01/E    01/B    10/U    01/B    11/B    33/W    32/W
4BQ 014/030 016/040 018/040 017/041 020/043 030/045 027/041
    02/J    01/B    11/B    00/B    11/B    33/W    32/W
BHK 011/025 015/035 019/037 017/039 020/040 027/041 024/037
    02/J    11/B    11/B    01/U    01/B    33/W    22/J
SHR 015/038 015/038 016/038 019/040 019/041 028/043 025/040
    01/B    01/B    10/U    01/B    12/J    34/W    43/W

&&

.BYZ WATCHES/WARNINGS/ADVISORIES...
MT...NONE.
WY...NONE.

&&

$$
WEATHER.GOV/BILLINGS



000
FXUS65 KBYZ 162123
AFDBYZ

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BILLINGS MT
223 PM MST TUE DEC 16 2014

.SHORT TERM...VALID FOR WED AND THU...

AREAS OF FOG STILL PERSISTING ACROSS PORTIONS OF SC/SE MT THIS
AFTERNOON. MOIST UPSLOPE FLOW OF AIR WITH LIGHT WINDS ALOFT IS
ALLOWING FOG TO CONTINUE OVER THE AREA. VISIBILITY HAS BEEN
IMPROVING OVER OUR WESTERN ZONES LATE THIS AFTERNOON AS A WEAK
DISTURBANCE MOVES TOWARD OUR REGION AND IS SPREADING MID LEVEL
CLOUD DECK ACROSS THE AREA. WILL GO AHEAD AND DROP THE DENSE FOG
ADVISORY FOR OUR WESTERN ZONES WITH IMPROVING VISIBILITIES. HRRR
IS SHOWING MOIST UPSLOPE FLOW TO CONTINUE OVERNIGHT AND FOG WILL
AGAIN BE POSSIBLE OVER MUCH OF OUR FORECAST AREA. MOISTURE NOT
AS DEEP AS THE PREVIOUS NIGHT AND DO NOT EXPECT WIDESPREAD FOG
WITH VISIBILITY BELOW A 1/2 MILE.

UPPER WAVE WILL DRIFT SLOWLY ACROSS THE AREA WEDNESDAY AS 300 MB
JET STAYS WELL SOUTH OF US. WEAK QG FORCING WITH THIS WAVE WILL
BRING SOME LIGHT SNOW TO THE PLAINS TOMORROW BUT NO SNOW
ACCUMULATIONS ARE EXPECTED. DRY WEATHER RETURNING TO THE PLAINS
WEDNESDAY NIGHT THROUGH THURSDAY AS WEAK SHORT WAVE RIDGING
MOVES ACROSS THE REGION. SOME MOUNTAIN SNOW SHOWERS WILL CONTINUE
THROUGH THIS PERIOD BUT AMOUNTS WILL BE LIGHT. WITH INCREASING
HEIGHTS WEDNESDAY AND THURSDAY...TEMPERATURES WILL CLIMB BACK TO
NEAR SEASONAL NORMALS. RICHMOND


.LONG TERM...VALID FOR FRI...SAT...SUN...MON...TUE...

MODELS CONTINUE TO INCREASE CONFIDENCE IN THE EXTENDED. BOTH THE
OPERATIONAL GFS AND ECMWF GENERALLY FIT WITHIN THE SPREAD OF THE
ENSEMBLE DATA. WEAK PACIFIC RIDGE WILL MOVE IN TO THE STATE
FRIDAY. SATURDAY ANOTHER SHORTWAVE WILL MOVE THROUGH...AS THE FLOW
INCREASES AND BECOMES MORE NORTHWESTERLY. PRECIP CHANCES WILL
INCREASE IN THE MOUNTAINS.

SUNDAY WILL SEE SOME LEESIDE TROUGHING DEVELOP. WINDS WILL PICKUP
AROUND NYE AND LIVINGSTON AS THE PRESSURE GRADIENT TIGHTENS DURING
THE DAY SUNDAY. WINDS WILL BEGIN TO INCREASE SUNDAY NIGHT TO AROUND
BILLINGS. FOR MONDAY...IT STILL LOOKS LIKE A COLD FRONT WILL MOVE
THROUGH AS A SURFACE LOW DROPS OUT OF CANADA...BRING PRECIP TO
MUCH OF THE AREA. AS WITH THE PREVIOUS FORECAST...MODELS CONTINUE
TO DEVELOP AN ATMOSPHERIC RIVER...GIVING THE AREA PLENTY OF
MOISTURE. WITH THIS STILL A LONG WAY OFF...HAVE OPTED TO CONTINUE
SIMILAR POPS TO THE PREVIOUS FORECAST. GIVEN THAT TEMPERATURES
WILL STILL BE WARM...LOOKS LIKE MUCH OF THE CENTRAL ZONES WILL
SEE RAIN THAT WILL SWITCH TO SNOW AS TEMPERATURES DROP MONDAY
NIGHT. REIMER
&&

.AVIATION...

LIFR TO MVFR CONDITIONS WILL PERSIST THROUGH THE AFTERNOON AND
OVERNIGHT. AS TEMPERATURES DROP A LITTLE AFTER SUNSET...SOME
LOCATIONS MAY SEE SOME LOWER CEILINGS AND VISIBILITIES DEVELOP
AGAIN. THINGS LOOK TO IMPROVE SOME DURING THE DAY TOMORROW.
MOUNTAIN OBSCURATIONS WILL BE WIDESPREAD THROUGH TONIGHT. REIMER

&&

.PRELIMINARY POINT TEMP/POPS...

    WED     THU     FRI     SAT     SUN     MON     TUE
-----------------------------------------------------------
BIL 020/036 022/039 023/038 027/042 026/044 035/047 030/041
    11/E    01/B    10/U    11/B    13/W    34/W    33/W
LVM 024/040 023/042 023/040 026/043 026/044 036/047 030/043
    22/J    11/E    11/B    11/N    13/W    33/W    33/W
HDN 014/032 015/037 016/037 020/040 019/041 029/044 026/040
    01/E    01/B    10/U    01/B    12/W    33/W    33/W
MLS 014/029 016/036 019/037 019/039 022/041 030/043 026/039
    01/E    01/B    10/U    01/B    11/B    33/W    32/W
4BQ 014/030 016/040 018/040 017/041 020/043 030/045 027/041
    02/J    01/B    11/B    00/B    11/B    33/W    32/W
BHK 011/025 015/035 019/037 017/039 020/040 027/041 024/037
    02/J    11/B    11/B    01/U    01/B    33/W    22/J
SHR 015/038 015/038 016/038 019/040 019/041 028/043 025/040
    01/B    01/B    10/U    01/B    12/J    34/W    43/W

&&

.BYZ WATCHES/WARNINGS/ADVISORIES...
MT...NONE.
WY...NONE.

&&

$$
WEATHER.GOV/BILLINGS




000
FXUS65 KGGW 162114
AFDGGW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GLASGOW MT
214 PM MST TUE DEC 16 2014

.SHORT TERM...FOR NORTHEAST MONTANA...TONIGHT THROUGH THURSDAY...
WARM DRY AIRMASS OVER A COLD MOIST LAYER NEAR THE SURFACE HAS
ALLOWED FOR FOR A STUBBORN WIDESPREAD STRATUS CLOUD DECK TO HANG
AROUND THE REGION TODAY. SATELLITE SHOWING IT EXTENDING FAR UPSTREAM
INTO THE CENTRAL PLAINS...SO THIS CLOUD DECK WILL REMAIN WITH US FOR
SOMETIME AS LONG AS OUR LOW LEVEL FLOW REMAINS FROM THE SOUTHEAST.

A SYSTEM WILL COMPLICATE THINGS A BIT AS IT MOVES INTO THE WESTERN
ZONES WEDNESDAY AND DIMINISHING AS IT MOVES EAST ACROSS THE CWA.
MOST OF THE PRECIPITATION LOOKS TO BE IN THE FORM OF SNOW BUT THERE
COULD BE AN ISOLATED LOCATION WHERE THERE ARE A FEW DROPS OF
FREEZING RAIN...SOMETHING THAT LOOKS A LOT LESS IMPACTFUL THAN
WHAT WE HAD SUNDAY. THEREFORE...NOT ANTICIPATING A BIG SHOW WITH
THIS SYSTEM.

BEHIND THIS SYSTEM...WINDS THURSDAY TURN AROUND TO THE SOUTHWEST.
THIS WILL ALLOW A WARMER AIRMASS TO MOVE IN AND TEMPS WARM INTO
THE UPPER 20S NORTH TO 30S TO AROUND 40 SOUTH. TFJ


.LONG TERM...THURSDAY NIGHT THROUGH TUESDAY...
THE 12Z GUIDANCE HAS SOMEWHAT MILDER TEMPERATURES THROUGH THE
EXTENDED PERIOD AS COMPARED WITH THE INHERITED FORECAST. GIVEN THE
POTENTIAL FOR THE NEXT WEATHER SYSTEM TO APPROACH IN NORTHWEST
FLOW ALOFT BY LATE NEXT WEEKEND...FELT THAT TEMPERATURES COULD BE
CRITICAL FOR DECIPHERING PRECIPITATION TYPE. THEREFORE DID SPEND
SOME TIME ON TEMPERATURE GRIDS WITH THIS PACKAGE.

THE LONG RANGE PERIOD WILL GET UNDERWAY THURSDAY NIGHT AND FRIDAY
WITH AN UPPER LEVEL RIDGE OVER MONTANA HELPING TO MAINTAIN FAIRLY
DRY CONDITIONS. ZONAL TO NORTHWEST FLOW ALOFT ENSUES BEHIND THE
RIDGE AS IT TRANSLATES EAST. A SHORTWAVE LOOKS TO APPROACH BY LATE
IN THE WEEKEND AND COMBINE WITH MOISTURE AS IT APPROACHES THE CWA.
PVA SHOULD HELP PROVIDE FORCING FOR ASCENT IN A MOISTENING
VERTICAL COLUMN. THE LATEST NOMADS ENSEMBLE PROBABILITY TOOL
SUGGESTS MEASURABLE PRECIPITATION IS A DECENT BET AS EARLY AS 00Z
MONDAY. THIS HAS SUPPORT FROM THE 12Z GFS AND ECMWF OPERATIONAL
MODELS. THERE ARE DIFFERENCES THOUGH ON TIMING/PLACEMENT OF BEST
DYNAMIC FORCING FOR ASCENT...AND SO FOR NOW DECIDED TO MAINTAIN
POPS IN THE SLIGHT CHANCE RANGE. BASED ON THIS REASONING
HOWEVER...DID NOT FEEL COMFORTABLE MAINTAINING A DRY FORECAST FOR
SUNDAY AND SUNDAY NIGHT. THERE IS PLENTY OF SUPPORT FOR A SLIGHT
CHANCE OF PRECIPITATION DURING THIS TIME AND GRIDS NOW REFLECT THIS.

THERMAL PROFILES THOUGH INDICATE THAT PRECIPITATION TYPE COULD BE
COMPLEX. FOR NOW WILL GO WITH A WINTRY MIX STARTING SUNDAY AND
WILL CONTINUE CHANCES INTO EARLY NEXT WEEK FOLLOWING SLIGHT
CHANCE/NEAR CLIMO POPS. AS MODELS SHOW BETTER CONSENSUS AND/OR RUN
TO RUN CONTINUITY...FINER AND MORE CONFIDENT DETAIL IN THE
FORECAST SHOULD RESULT OVER TIME. MALIAWCO

PREVIOUS LONG TERM DISCUSSION...
SYNOPTIC SET UP... WITH WEAK POOLED COLD AIR AT THE SURFACE OVER
THE EASTERN GREAT PLAINS. A RIDGE RUNS UP THE COAST FROM
CALIFORNIA TO SOUTHERN BRITISH COLUMBIA. NORTHEAST MONTANA LIES
BETWEEN THESE TWO FEATURES IN A UNENERGETIC WEAK NORTHWESTERN
FLOW. COLDEST AIR OF THE NORTHERN HEMISPHERE LIES BOTTLED UP OVER
THE ARCTIC.

THURSDAY NIGHT THROUGH SUNDAY... RIDGE TO THE WEST GAINS
INCREASING INFLUENCE AND PLACES NORTHEAST MONTANA UNDER PARTLY
CLOUDY AND DRY CONDITIONS DUE TO A STABLE ATMOSPHERE. SUBTLE
SHORTWAVES APPEAR IN THE FLOW... ESPECIALLY ON SATURDAY... BUT
REMAIN RELATIVELY UN-ENERGIZED AND SEEM INSUFFICIENT TO CAUSE
PRECIPITATION AT THIS TIME.

SUNDAY NIGHT ONWARD... WESTERN RIDGE WILL FINALLY MOVE THROUGH
THE AREA AND GENERATE CONDITIONS FOR A PREFRONTAL WARMING SPIKE
ON SUNDAY NIGHT. BY MONDAY AN ARCTIC INTRUSION IS ANTICIPATED TO
BEGIN AND WILL BRING A COLD FRONT THROUGH THE REGION. POSSIBLE
PACIFIC MOISTURE AT THE CREST OF THE EXITING RIDGE COULD HELP TO
GENERATE SHOWER STARTING DURING THIS PERIOD AND LASTING THROUGH
TUESDAY. AFTERWARD TEMPERATURES ARE EXPECTED TO BEGIN DROPPING
OFF.

GAH

&&

.AVIATION...
MVFR TO IFR STRATUS WILL CONTINUE OVER THE TAF SITES TONIGHT.
PATCHY FREEZING FOG IS ALSO POSSIBLE WHICH COULD LEAD TO RESTRICTED
VISIBILITY AT TIMES. CONFIDENCE ON FOG HOWEVER IS CURRENTLY LOW.
SOUTHEAST WINDS WILL HOVER AROUND 10 KTS. MALIAWCO


&&

.GLASGOW WATCHES/WARNINGS/ADVISORIES...NONE.

&&

$$

WEATHER.GOV/GLASGOW






000
FXUS65 KGGW 162114
AFDGGW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GLASGOW MT
214 PM MST TUE DEC 16 2014

.SHORT TERM...FOR NORTHEAST MONTANA...TONIGHT THROUGH THURSDAY...
WARM DRY AIRMASS OVER A COLD MOIST LAYER NEAR THE SURFACE HAS
ALLOWED FOR FOR A STUBBORN WIDESPREAD STRATUS CLOUD DECK TO HANG
AROUND THE REGION TODAY. SATELLITE SHOWING IT EXTENDING FAR UPSTREAM
INTO THE CENTRAL PLAINS...SO THIS CLOUD DECK WILL REMAIN WITH US FOR
SOMETIME AS LONG AS OUR LOW LEVEL FLOW REMAINS FROM THE SOUTHEAST.

A SYSTEM WILL COMPLICATE THINGS A BIT AS IT MOVES INTO THE WESTERN
ZONES WEDNESDAY AND DIMINISHING AS IT MOVES EAST ACROSS THE CWA.
MOST OF THE PRECIPITATION LOOKS TO BE IN THE FORM OF SNOW BUT THERE
COULD BE AN ISOLATED LOCATION WHERE THERE ARE A FEW DROPS OF
FREEZING RAIN...SOMETHING THAT LOOKS A LOT LESS IMPACTFUL THAN
WHAT WE HAD SUNDAY. THEREFORE...NOT ANTICIPATING A BIG SHOW WITH
THIS SYSTEM.

BEHIND THIS SYSTEM...WINDS THURSDAY TURN AROUND TO THE SOUTHWEST.
THIS WILL ALLOW A WARMER AIRMASS TO MOVE IN AND TEMPS WARM INTO
THE UPPER 20S NORTH TO 30S TO AROUND 40 SOUTH. TFJ


.LONG TERM...THURSDAY NIGHT THROUGH TUESDAY...
THE 12Z GUIDANCE HAS SOMEWHAT MILDER TEMPERATURES THROUGH THE
EXTENDED PERIOD AS COMPARED WITH THE INHERITED FORECAST. GIVEN THE
POTENTIAL FOR THE NEXT WEATHER SYSTEM TO APPROACH IN NORTHWEST
FLOW ALOFT BY LATE NEXT WEEKEND...FELT THAT TEMPERATURES COULD BE
CRITICAL FOR DECIPHERING PRECIPITATION TYPE. THEREFORE DID SPEND
SOME TIME ON TEMPERATURE GRIDS WITH THIS PACKAGE.

THE LONG RANGE PERIOD WILL GET UNDERWAY THURSDAY NIGHT AND FRIDAY
WITH AN UPPER LEVEL RIDGE OVER MONTANA HELPING TO MAINTAIN FAIRLY
DRY CONDITIONS. ZONAL TO NORTHWEST FLOW ALOFT ENSUES BEHIND THE
RIDGE AS IT TRANSLATES EAST. A SHORTWAVE LOOKS TO APPROACH BY LATE
IN THE WEEKEND AND COMBINE WITH MOISTURE AS IT APPROACHES THE CWA.
PVA SHOULD HELP PROVIDE FORCING FOR ASCENT IN A MOISTENING
VERTICAL COLUMN. THE LATEST NOMADS ENSEMBLE PROBABILITY TOOL
SUGGESTS MEASURABLE PRECIPITATION IS A DECENT BET AS EARLY AS 00Z
MONDAY. THIS HAS SUPPORT FROM THE 12Z GFS AND ECMWF OPERATIONAL
MODELS. THERE ARE DIFFERENCES THOUGH ON TIMING/PLACEMENT OF BEST
DYNAMIC FORCING FOR ASCENT...AND SO FOR NOW DECIDED TO MAINTAIN
POPS IN THE SLIGHT CHANCE RANGE. BASED ON THIS REASONING
HOWEVER...DID NOT FEEL COMFORTABLE MAINTAINING A DRY FORECAST FOR
SUNDAY AND SUNDAY NIGHT. THERE IS PLENTY OF SUPPORT FOR A SLIGHT
CHANCE OF PRECIPITATION DURING THIS TIME AND GRIDS NOW REFLECT THIS.

THERMAL PROFILES THOUGH INDICATE THAT PRECIPITATION TYPE COULD BE
COMPLEX. FOR NOW WILL GO WITH A WINTRY MIX STARTING SUNDAY AND
WILL CONTINUE CHANCES INTO EARLY NEXT WEEK FOLLOWING SLIGHT
CHANCE/NEAR CLIMO POPS. AS MODELS SHOW BETTER CONSENSUS AND/OR RUN
TO RUN CONTINUITY...FINER AND MORE CONFIDENT DETAIL IN THE
FORECAST SHOULD RESULT OVER TIME. MALIAWCO

PREVIOUS LONG TERM DISCUSSION...
SYNOPTIC SET UP... WITH WEAK POOLED COLD AIR AT THE SURFACE OVER
THE EASTERN GREAT PLAINS. A RIDGE RUNS UP THE COAST FROM
CALIFORNIA TO SOUTHERN BRITISH COLUMBIA. NORTHEAST MONTANA LIES
BETWEEN THESE TWO FEATURES IN A UNENERGETIC WEAK NORTHWESTERN
FLOW. COLDEST AIR OF THE NORTHERN HEMISPHERE LIES BOTTLED UP OVER
THE ARCTIC.

THURSDAY NIGHT THROUGH SUNDAY... RIDGE TO THE WEST GAINS
INCREASING INFLUENCE AND PLACES NORTHEAST MONTANA UNDER PARTLY
CLOUDY AND DRY CONDITIONS DUE TO A STABLE ATMOSPHERE. SUBTLE
SHORTWAVES APPEAR IN THE FLOW... ESPECIALLY ON SATURDAY... BUT
REMAIN RELATIVELY UN-ENERGIZED AND SEEM INSUFFICIENT TO CAUSE
PRECIPITATION AT THIS TIME.

SUNDAY NIGHT ONWARD... WESTERN RIDGE WILL FINALLY MOVE THROUGH
THE AREA AND GENERATE CONDITIONS FOR A PREFRONTAL WARMING SPIKE
ON SUNDAY NIGHT. BY MONDAY AN ARCTIC INTRUSION IS ANTICIPATED TO
BEGIN AND WILL BRING A COLD FRONT THROUGH THE REGION. POSSIBLE
PACIFIC MOISTURE AT THE CREST OF THE EXITING RIDGE COULD HELP TO
GENERATE SHOWER STARTING DURING THIS PERIOD AND LASTING THROUGH
TUESDAY. AFTERWARD TEMPERATURES ARE EXPECTED TO BEGIN DROPPING
OFF.

GAH

&&

.AVIATION...
MVFR TO IFR STRATUS WILL CONTINUE OVER THE TAF SITES TONIGHT.
PATCHY FREEZING FOG IS ALSO POSSIBLE WHICH COULD LEAD TO RESTRICTED
VISIBILITY AT TIMES. CONFIDENCE ON FOG HOWEVER IS CURRENTLY LOW.
SOUTHEAST WINDS WILL HOVER AROUND 10 KTS. MALIAWCO


&&

.GLASGOW WATCHES/WARNINGS/ADVISORIES...NONE.

&&

$$

WEATHER.GOV/GLASGOW





000
FXUS65 KBYZ 161803
AFDBYZ

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BILLINGS MT
1103 AM MST TUE DEC 16 2014

.UPDATE...
A QUICK UPDATE TO EXTEND THE DENSE FOG ADVISORY FOR STILLWATER
SWEET GRASS AND WHEATLAND COUNTY THROUGH 2 PM THIS AFTERNOON.
DENSE FOG WITH VISIBILITY LESS THAN A 1/4 MILES IS CONTINUING
OVER THESE AREAS AS A RESULT OF A MOIST UPSLOPE SURFACE FLOW. WILL
KEEP AREAS OF FOG GOING FOR SHERIDAN NORTHWARD THROUGH BILLINGS
AND ROUNDUP INTO THE EARLY AFTERNOON HOURS ALSO. NO OTHER CHANGES
MADE TO THE FORECAST. RICHMOND

&&

.SHORT TERM...VALID FOR TDY AND WED...

MAIN FORECAST PROBLEM FOR THE SHORT TERM CONCERNS CONSIDERABLE
AREAS OF FOG ACROSS THE FORECAST AREA...PARTICULARLY IN THE LOWER
ELEVATIONS OF THE WESTERN ZONES. THE PATTERN FAVORS THIS TO
CONTINUE WITH A RIDGE ALOFT AND SURFACE LOW PRESSURE TO OUR
WEST/SOUTHWEST THIS IS KEEPING A SOUTHEAST LOW LEVEL FLOW
UPSLOPING INTO SOUTH CENTRAL MONTANA. LOCAL OBSERVATIONS SHOW A
QUARTER MILE VISIBILITY OR LESS IN AREAS JUST WEST OF BILLINGS TO
LIVINGSTON AND UP TO JUDITH GAP. MESOSCALE CROSS SECTIONS SHOW
THIS PERSISTING THROUGH MUCH OF THE MORNING FOR THIS AREA...AND
PERHAPS EVEN INTO THE AFTERNOON FOR PARK COUNTY AROUND LIVINGSTON.
THIS WILL ALSO TEND TO PREVENT MUCH IF ANY SOLAR RADIATION FOR
MUCH OF THE DAY AND SINCE MOS GUIDANCE IS NOT TAKING IT INTO
ACCOUNT I WILL BE SURE TO UNDERCUT GUIDANCE IN THESE AREAS. MAIN
MESSAGE...FOGGY AND CONTINUED CHILLY MOST LOCATIONS TODAY.

DENSE FOG ADVISORY...ISSUED ACROSS AREAS GENERALLY FROM LIVINGSTON
TO BIG TIMBER AND UP TO JUDITH GAP WHERE OBSERVATIONS INDICATE
PERSISTENT DENSE FOG. LOCALLY ICY ROADS WILL MAKE THIS EVEN MORE
DANGEROUS. AS MENTIONED BEFORE PROGGS SUGGEST THE WIDESPREAD FOG
WILL LINGER IN THESE AREAS UNTIL ABOUT 18Z.

IN THE MEANTIME...THE 500MB RIDGE BUILDING OVER US NOW WILL
QUICKLY BREAK DOWN LATE TODAY AND TONIGHT AS ANOTHER BROAD SPLIT
FLOW TROUGH MOVES INTO THE WESTERN UNITED STATES. A WEAKER SHORT
WAVE IN THE MEAN FLOW WILL SPLIT FROM THE SOUTHERN BRANCH AND
TRACK OVER OUR REGION TONIGHT AND INTO WEDNESDAY. QPF PROGGS ARE
NOT IMPRESSIVE BUT SEEMS PRUDENT TO BUMP UP SOME OF THE POPS NOW
FOR THE HIGH COUNTRY. WE MAY SEE SOME FLURRIES OR LIGHT SNOW IN
THE EAST AS IT MOVES THROUGH WEDNESDAY MORNING AS WELL. LOOK FOR A
MODEST WARM UP TO AROUND SEASONAL AVERAGES FOR WEDNESDAY. BT

.LONG TERM...VALID FOR THU...FRI...SAT...SUN...MON...

ENSEMBLE FORECASTS FROM THE GFS AND ECMWF WERE SHOWING MORE
CONFIDENCE IN THEIR SOLUTIONS FOR THE EXTENDED PERIOD THAN THEY
HAVE IN PREVIOUS RUNS.

FLOW GENERALLY BECOMES MORE PROGRESSIVE WITH TIME. WEAK NORTHERN
STREAM OF A PACIFIC TROUGH WILL BE OVER THE REGION ON THU. THIS
WILL BE FOLLOWED BY A SHORTWAVE RIDGE ON FRI AND ANOTHER WEAK
TROUGH FOR SAT. WENT WITH SUPER BLEND POPS FOR THIS PERIOD WHERE
MOISTURE AFFECTS MAINLY THE MOUNTAINS. A STRONG PACIFIC JET WILL
MOVE INTO THE REGION LATE IN THE PERIOD WHICH RESULTS IN A FAST
WNW FLOW OVERTAKING THE AREA BEGINNING ON SUN. ENERGY WILL MOVE
THROUGH THIS FLOW ALONG WITH PERIODS OF PACIFIC MOISTURE. GEFS
SHOWED AN ATMOSPHERIC RIVER WILL AFFECT THE REGION SUN INTO MON
WHICH WILL CONTRIBUTE TO PRECIPITATION CHANCES. HAVE INCREASED
POPS OVER THE AREA BEGINNING ON SUN. MAY HAVE GAP WIND ISSUES SAT
NIGHT INTO MON AS MODELS AGREED ON STRONG LEE TROUGHING OVER THE
AREA. WILL CONTINUE TO HAVE STRONG WINDS IN THE FORECAST FOR THE
GAP AREAS. THE MODELS WERE IN GOOD AGREEMENT WITH TEMPERATURES
THROUGH THE EXTENDED AND SHOWED ABOVE NORMAL READINGS. ARTHUR
&&

.AVIATION...

LIFR TO VLIFR CONDITIONS IN STRATUS AND FOG WILL PERSIST FROM
ROSEBUD COUNTY W THROUGH MOST OF THE DAY. LATEST SHORT RANGE
GUIDANCE SHOWS LITTLE IMPROVEMENT. TONIGHT CONDITIONS WILL LIKELY
DEGRADE FROM ANY IMPROVEMENTS TODAY. MOUNTAIN OBSCURATIONS WILL
BE WIDESPREAD THROUGH TONIGHT. REIMER

&&

.PRELIMINARY POINT TEMP/POPS...

    TDY WED     THU     FRI     SAT     SUN     MON
-------------------------------------------------------
BIL 027 020/036 022/039 023/039 026/042 025/043 035/045
    0/B 11/B    01/B    10/U    11/B    12/W    23/W
LVM 029 024/042 023/042 022/041 026/043 026/043 033/045
    1/E 22/J    11/E    11/U    11/B    13/W    33/W
HDN 029 014/033 015/037 017/038 019/040 019/041 028/043
    0/E 01/B    01/B    10/U    01/B    11/B    23/W
MLS 027 015/030 017/036 019/037 018/038 022/039 028/042
    0/E 01/B    01/B    10/U    01/U    11/U    23/W
4BQ 030 015/033 016/040 018/040 016/041 020/042 027/043
    0/E 02/J    01/B    10/U    01/U    11/B    23/W
BHK 024 012/028 015/035 019/037 016/038 020/039 025/041
    0/E 02/J    11/B    11/U    01/U    11/B    23/W
SHR 028 015/036 016/038 016/038 019/040 019/041 026/042
    0/B 01/B    01/B    10/U    01/B    12/J    33/W

&&

.BYZ WATCHES/WARNINGS/ADVISORIES...
MT...DENSE FOG ADVISORY IN EFFECT UNTIL 2 PM MST THIS AFTERNOON
      FOR ZONES 28-34-41-63.
WY...NONE.

&&

$$
WEATHER.GOV/BILLINGS




000
FXUS65 KBYZ 161803
AFDBYZ

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BILLINGS MT
1103 AM MST TUE DEC 16 2014

.UPDATE...
A QUICK UPDATE TO EXTEND THE DENSE FOG ADVISORY FOR STILLWATER
SWEET GRASS AND WHEATLAND COUNTY THROUGH 2 PM THIS AFTERNOON.
DENSE FOG WITH VISIBILITY LESS THAN A 1/4 MILES IS CONTINUING
OVER THESE AREAS AS A RESULT OF A MOIST UPSLOPE SURFACE FLOW. WILL
KEEP AREAS OF FOG GOING FOR SHERIDAN NORTHWARD THROUGH BILLINGS
AND ROUNDUP INTO THE EARLY AFTERNOON HOURS ALSO. NO OTHER CHANGES
MADE TO THE FORECAST. RICHMOND

&&

.SHORT TERM...VALID FOR TDY AND WED...

MAIN FORECAST PROBLEM FOR THE SHORT TERM CONCERNS CONSIDERABLE
AREAS OF FOG ACROSS THE FORECAST AREA...PARTICULARLY IN THE LOWER
ELEVATIONS OF THE WESTERN ZONES. THE PATTERN FAVORS THIS TO
CONTINUE WITH A RIDGE ALOFT AND SURFACE LOW PRESSURE TO OUR
WEST/SOUTHWEST THIS IS KEEPING A SOUTHEAST LOW LEVEL FLOW
UPSLOPING INTO SOUTH CENTRAL MONTANA. LOCAL OBSERVATIONS SHOW A
QUARTER MILE VISIBILITY OR LESS IN AREAS JUST WEST OF BILLINGS TO
LIVINGSTON AND UP TO JUDITH GAP. MESOSCALE CROSS SECTIONS SHOW
THIS PERSISTING THROUGH MUCH OF THE MORNING FOR THIS AREA...AND
PERHAPS EVEN INTO THE AFTERNOON FOR PARK COUNTY AROUND LIVINGSTON.
THIS WILL ALSO TEND TO PREVENT MUCH IF ANY SOLAR RADIATION FOR
MUCH OF THE DAY AND SINCE MOS GUIDANCE IS NOT TAKING IT INTO
ACCOUNT I WILL BE SURE TO UNDERCUT GUIDANCE IN THESE AREAS. MAIN
MESSAGE...FOGGY AND CONTINUED CHILLY MOST LOCATIONS TODAY.

DENSE FOG ADVISORY...ISSUED ACROSS AREAS GENERALLY FROM LIVINGSTON
TO BIG TIMBER AND UP TO JUDITH GAP WHERE OBSERVATIONS INDICATE
PERSISTENT DENSE FOG. LOCALLY ICY ROADS WILL MAKE THIS EVEN MORE
DANGEROUS. AS MENTIONED BEFORE PROGGS SUGGEST THE WIDESPREAD FOG
WILL LINGER IN THESE AREAS UNTIL ABOUT 18Z.

IN THE MEANTIME...THE 500MB RIDGE BUILDING OVER US NOW WILL
QUICKLY BREAK DOWN LATE TODAY AND TONIGHT AS ANOTHER BROAD SPLIT
FLOW TROUGH MOVES INTO THE WESTERN UNITED STATES. A WEAKER SHORT
WAVE IN THE MEAN FLOW WILL SPLIT FROM THE SOUTHERN BRANCH AND
TRACK OVER OUR REGION TONIGHT AND INTO WEDNESDAY. QPF PROGGS ARE
NOT IMPRESSIVE BUT SEEMS PRUDENT TO BUMP UP SOME OF THE POPS NOW
FOR THE HIGH COUNTRY. WE MAY SEE SOME FLURRIES OR LIGHT SNOW IN
THE EAST AS IT MOVES THROUGH WEDNESDAY MORNING AS WELL. LOOK FOR A
MODEST WARM UP TO AROUND SEASONAL AVERAGES FOR WEDNESDAY. BT

.LONG TERM...VALID FOR THU...FRI...SAT...SUN...MON...

ENSEMBLE FORECASTS FROM THE GFS AND ECMWF WERE SHOWING MORE
CONFIDENCE IN THEIR SOLUTIONS FOR THE EXTENDED PERIOD THAN THEY
HAVE IN PREVIOUS RUNS.

FLOW GENERALLY BECOMES MORE PROGRESSIVE WITH TIME. WEAK NORTHERN
STREAM OF A PACIFIC TROUGH WILL BE OVER THE REGION ON THU. THIS
WILL BE FOLLOWED BY A SHORTWAVE RIDGE ON FRI AND ANOTHER WEAK
TROUGH FOR SAT. WENT WITH SUPER BLEND POPS FOR THIS PERIOD WHERE
MOISTURE AFFECTS MAINLY THE MOUNTAINS. A STRONG PACIFIC JET WILL
MOVE INTO THE REGION LATE IN THE PERIOD WHICH RESULTS IN A FAST
WNW FLOW OVERTAKING THE AREA BEGINNING ON SUN. ENERGY WILL MOVE
THROUGH THIS FLOW ALONG WITH PERIODS OF PACIFIC MOISTURE. GEFS
SHOWED AN ATMOSPHERIC RIVER WILL AFFECT THE REGION SUN INTO MON
WHICH WILL CONTRIBUTE TO PRECIPITATION CHANCES. HAVE INCREASED
POPS OVER THE AREA BEGINNING ON SUN. MAY HAVE GAP WIND ISSUES SAT
NIGHT INTO MON AS MODELS AGREED ON STRONG LEE TROUGHING OVER THE
AREA. WILL CONTINUE TO HAVE STRONG WINDS IN THE FORECAST FOR THE
GAP AREAS. THE MODELS WERE IN GOOD AGREEMENT WITH TEMPERATURES
THROUGH THE EXTENDED AND SHOWED ABOVE NORMAL READINGS. ARTHUR
&&

.AVIATION...

LIFR TO VLIFR CONDITIONS IN STRATUS AND FOG WILL PERSIST FROM
ROSEBUD COUNTY W THROUGH MOST OF THE DAY. LATEST SHORT RANGE
GUIDANCE SHOWS LITTLE IMPROVEMENT. TONIGHT CONDITIONS WILL LIKELY
DEGRADE FROM ANY IMPROVEMENTS TODAY. MOUNTAIN OBSCURATIONS WILL
BE WIDESPREAD THROUGH TONIGHT. REIMER

&&

.PRELIMINARY POINT TEMP/POPS...

    TDY WED     THU     FRI     SAT     SUN     MON
-------------------------------------------------------
BIL 027 020/036 022/039 023/039 026/042 025/043 035/045
    0/B 11/B    01/B    10/U    11/B    12/W    23/W
LVM 029 024/042 023/042 022/041 026/043 026/043 033/045
    1/E 22/J    11/E    11/U    11/B    13/W    33/W
HDN 029 014/033 015/037 017/038 019/040 019/041 028/043
    0/E 01/B    01/B    10/U    01/B    11/B    23/W
MLS 027 015/030 017/036 019/037 018/038 022/039 028/042
    0/E 01/B    01/B    10/U    01/U    11/U    23/W
4BQ 030 015/033 016/040 018/040 016/041 020/042 027/043
    0/E 02/J    01/B    10/U    01/U    11/B    23/W
BHK 024 012/028 015/035 019/037 016/038 020/039 025/041
    0/E 02/J    11/B    11/U    01/U    11/B    23/W
SHR 028 015/036 016/038 016/038 019/040 019/041 026/042
    0/B 01/B    01/B    10/U    01/B    12/J    33/W

&&

.BYZ WATCHES/WARNINGS/ADVISORIES...
MT...DENSE FOG ADVISORY IN EFFECT UNTIL 2 PM MST THIS AFTERNOON
      FOR ZONES 28-34-41-63.
WY...NONE.

&&

$$
WEATHER.GOV/BILLINGS




000
FXUS65 KBYZ 161803
AFDBYZ

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BILLINGS MT
1103 AM MST TUE DEC 16 2014

.UPDATE...
A QUICK UPDATE TO EXTEND THE DENSE FOG ADVISORY FOR STILLWATER
SWEET GRASS AND WHEATLAND COUNTY THROUGH 2 PM THIS AFTERNOON.
DENSE FOG WITH VISIBILITY LESS THAN A 1/4 MILES IS CONTINUING
OVER THESE AREAS AS A RESULT OF A MOIST UPSLOPE SURFACE FLOW. WILL
KEEP AREAS OF FOG GOING FOR SHERIDAN NORTHWARD THROUGH BILLINGS
AND ROUNDUP INTO THE EARLY AFTERNOON HOURS ALSO. NO OTHER CHANGES
MADE TO THE FORECAST. RICHMOND

&&

.SHORT TERM...VALID FOR TDY AND WED...

MAIN FORECAST PROBLEM FOR THE SHORT TERM CONCERNS CONSIDERABLE
AREAS OF FOG ACROSS THE FORECAST AREA...PARTICULARLY IN THE LOWER
ELEVATIONS OF THE WESTERN ZONES. THE PATTERN FAVORS THIS TO
CONTINUE WITH A RIDGE ALOFT AND SURFACE LOW PRESSURE TO OUR
WEST/SOUTHWEST THIS IS KEEPING A SOUTHEAST LOW LEVEL FLOW
UPSLOPING INTO SOUTH CENTRAL MONTANA. LOCAL OBSERVATIONS SHOW A
QUARTER MILE VISIBILITY OR LESS IN AREAS JUST WEST OF BILLINGS TO
LIVINGSTON AND UP TO JUDITH GAP. MESOSCALE CROSS SECTIONS SHOW
THIS PERSISTING THROUGH MUCH OF THE MORNING FOR THIS AREA...AND
PERHAPS EVEN INTO THE AFTERNOON FOR PARK COUNTY AROUND LIVINGSTON.
THIS WILL ALSO TEND TO PREVENT MUCH IF ANY SOLAR RADIATION FOR
MUCH OF THE DAY AND SINCE MOS GUIDANCE IS NOT TAKING IT INTO
ACCOUNT I WILL BE SURE TO UNDERCUT GUIDANCE IN THESE AREAS. MAIN
MESSAGE...FOGGY AND CONTINUED CHILLY MOST LOCATIONS TODAY.

DENSE FOG ADVISORY...ISSUED ACROSS AREAS GENERALLY FROM LIVINGSTON
TO BIG TIMBER AND UP TO JUDITH GAP WHERE OBSERVATIONS INDICATE
PERSISTENT DENSE FOG. LOCALLY ICY ROADS WILL MAKE THIS EVEN MORE
DANGEROUS. AS MENTIONED BEFORE PROGGS SUGGEST THE WIDESPREAD FOG
WILL LINGER IN THESE AREAS UNTIL ABOUT 18Z.

IN THE MEANTIME...THE 500MB RIDGE BUILDING OVER US NOW WILL
QUICKLY BREAK DOWN LATE TODAY AND TONIGHT AS ANOTHER BROAD SPLIT
FLOW TROUGH MOVES INTO THE WESTERN UNITED STATES. A WEAKER SHORT
WAVE IN THE MEAN FLOW WILL SPLIT FROM THE SOUTHERN BRANCH AND
TRACK OVER OUR REGION TONIGHT AND INTO WEDNESDAY. QPF PROGGS ARE
NOT IMPRESSIVE BUT SEEMS PRUDENT TO BUMP UP SOME OF THE POPS NOW
FOR THE HIGH COUNTRY. WE MAY SEE SOME FLURRIES OR LIGHT SNOW IN
THE EAST AS IT MOVES THROUGH WEDNESDAY MORNING AS WELL. LOOK FOR A
MODEST WARM UP TO AROUND SEASONAL AVERAGES FOR WEDNESDAY. BT

.LONG TERM...VALID FOR THU...FRI...SAT...SUN...MON...

ENSEMBLE FORECASTS FROM THE GFS AND ECMWF WERE SHOWING MORE
CONFIDENCE IN THEIR SOLUTIONS FOR THE EXTENDED PERIOD THAN THEY
HAVE IN PREVIOUS RUNS.

FLOW GENERALLY BECOMES MORE PROGRESSIVE WITH TIME. WEAK NORTHERN
STREAM OF A PACIFIC TROUGH WILL BE OVER THE REGION ON THU. THIS
WILL BE FOLLOWED BY A SHORTWAVE RIDGE ON FRI AND ANOTHER WEAK
TROUGH FOR SAT. WENT WITH SUPER BLEND POPS FOR THIS PERIOD WHERE
MOISTURE AFFECTS MAINLY THE MOUNTAINS. A STRONG PACIFIC JET WILL
MOVE INTO THE REGION LATE IN THE PERIOD WHICH RESULTS IN A FAST
WNW FLOW OVERTAKING THE AREA BEGINNING ON SUN. ENERGY WILL MOVE
THROUGH THIS FLOW ALONG WITH PERIODS OF PACIFIC MOISTURE. GEFS
SHOWED AN ATMOSPHERIC RIVER WILL AFFECT THE REGION SUN INTO MON
WHICH WILL CONTRIBUTE TO PRECIPITATION CHANCES. HAVE INCREASED
POPS OVER THE AREA BEGINNING ON SUN. MAY HAVE GAP WIND ISSUES SAT
NIGHT INTO MON AS MODELS AGREED ON STRONG LEE TROUGHING OVER THE
AREA. WILL CONTINUE TO HAVE STRONG WINDS IN THE FORECAST FOR THE
GAP AREAS. THE MODELS WERE IN GOOD AGREEMENT WITH TEMPERATURES
THROUGH THE EXTENDED AND SHOWED ABOVE NORMAL READINGS. ARTHUR
&&

.AVIATION...

LIFR TO VLIFR CONDITIONS IN STRATUS AND FOG WILL PERSIST FROM
ROSEBUD COUNTY W THROUGH MOST OF THE DAY. LATEST SHORT RANGE
GUIDANCE SHOWS LITTLE IMPROVEMENT. TONIGHT CONDITIONS WILL LIKELY
DEGRADE FROM ANY IMPROVEMENTS TODAY. MOUNTAIN OBSCURATIONS WILL
BE WIDESPREAD THROUGH TONIGHT. REIMER

&&

.PRELIMINARY POINT TEMP/POPS...

    TDY WED     THU     FRI     SAT     SUN     MON
-------------------------------------------------------
BIL 027 020/036 022/039 023/039 026/042 025/043 035/045
    0/B 11/B    01/B    10/U    11/B    12/W    23/W
LVM 029 024/042 023/042 022/041 026/043 026/043 033/045
    1/E 22/J    11/E    11/U    11/B    13/W    33/W
HDN 029 014/033 015/037 017/038 019/040 019/041 028/043
    0/E 01/B    01/B    10/U    01/B    11/B    23/W
MLS 027 015/030 017/036 019/037 018/038 022/039 028/042
    0/E 01/B    01/B    10/U    01/U    11/U    23/W
4BQ 030 015/033 016/040 018/040 016/041 020/042 027/043
    0/E 02/J    01/B    10/U    01/U    11/B    23/W
BHK 024 012/028 015/035 019/037 016/038 020/039 025/041
    0/E 02/J    11/B    11/U    01/U    11/B    23/W
SHR 028 015/036 016/038 016/038 019/040 019/041 026/042
    0/B 01/B    01/B    10/U    01/B    12/J    33/W

&&

.BYZ WATCHES/WARNINGS/ADVISORIES...
MT...DENSE FOG ADVISORY IN EFFECT UNTIL 2 PM MST THIS AFTERNOON
      FOR ZONES 28-34-41-63.
WY...NONE.

&&

$$
WEATHER.GOV/BILLINGS




000
FXUS65 KBYZ 161803
AFDBYZ

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BILLINGS MT
1103 AM MST TUE DEC 16 2014

.UPDATE...
A QUICK UPDATE TO EXTEND THE DENSE FOG ADVISORY FOR STILLWATER
SWEET GRASS AND WHEATLAND COUNTY THROUGH 2 PM THIS AFTERNOON.
DENSE FOG WITH VISIBILITY LESS THAN A 1/4 MILES IS CONTINUING
OVER THESE AREAS AS A RESULT OF A MOIST UPSLOPE SURFACE FLOW. WILL
KEEP AREAS OF FOG GOING FOR SHERIDAN NORTHWARD THROUGH BILLINGS
AND ROUNDUP INTO THE EARLY AFTERNOON HOURS ALSO. NO OTHER CHANGES
MADE TO THE FORECAST. RICHMOND

&&

.SHORT TERM...VALID FOR TDY AND WED...

MAIN FORECAST PROBLEM FOR THE SHORT TERM CONCERNS CONSIDERABLE
AREAS OF FOG ACROSS THE FORECAST AREA...PARTICULARLY IN THE LOWER
ELEVATIONS OF THE WESTERN ZONES. THE PATTERN FAVORS THIS TO
CONTINUE WITH A RIDGE ALOFT AND SURFACE LOW PRESSURE TO OUR
WEST/SOUTHWEST THIS IS KEEPING A SOUTHEAST LOW LEVEL FLOW
UPSLOPING INTO SOUTH CENTRAL MONTANA. LOCAL OBSERVATIONS SHOW A
QUARTER MILE VISIBILITY OR LESS IN AREAS JUST WEST OF BILLINGS TO
LIVINGSTON AND UP TO JUDITH GAP. MESOSCALE CROSS SECTIONS SHOW
THIS PERSISTING THROUGH MUCH OF THE MORNING FOR THIS AREA...AND
PERHAPS EVEN INTO THE AFTERNOON FOR PARK COUNTY AROUND LIVINGSTON.
THIS WILL ALSO TEND TO PREVENT MUCH IF ANY SOLAR RADIATION FOR
MUCH OF THE DAY AND SINCE MOS GUIDANCE IS NOT TAKING IT INTO
ACCOUNT I WILL BE SURE TO UNDERCUT GUIDANCE IN THESE AREAS. MAIN
MESSAGE...FOGGY AND CONTINUED CHILLY MOST LOCATIONS TODAY.

DENSE FOG ADVISORY...ISSUED ACROSS AREAS GENERALLY FROM LIVINGSTON
TO BIG TIMBER AND UP TO JUDITH GAP WHERE OBSERVATIONS INDICATE
PERSISTENT DENSE FOG. LOCALLY ICY ROADS WILL MAKE THIS EVEN MORE
DANGEROUS. AS MENTIONED BEFORE PROGGS SUGGEST THE WIDESPREAD FOG
WILL LINGER IN THESE AREAS UNTIL ABOUT 18Z.

IN THE MEANTIME...THE 500MB RIDGE BUILDING OVER US NOW WILL
QUICKLY BREAK DOWN LATE TODAY AND TONIGHT AS ANOTHER BROAD SPLIT
FLOW TROUGH MOVES INTO THE WESTERN UNITED STATES. A WEAKER SHORT
WAVE IN THE MEAN FLOW WILL SPLIT FROM THE SOUTHERN BRANCH AND
TRACK OVER OUR REGION TONIGHT AND INTO WEDNESDAY. QPF PROGGS ARE
NOT IMPRESSIVE BUT SEEMS PRUDENT TO BUMP UP SOME OF THE POPS NOW
FOR THE HIGH COUNTRY. WE MAY SEE SOME FLURRIES OR LIGHT SNOW IN
THE EAST AS IT MOVES THROUGH WEDNESDAY MORNING AS WELL. LOOK FOR A
MODEST WARM UP TO AROUND SEASONAL AVERAGES FOR WEDNESDAY. BT

.LONG TERM...VALID FOR THU...FRI...SAT...SUN...MON...

ENSEMBLE FORECASTS FROM THE GFS AND ECMWF WERE SHOWING MORE
CONFIDENCE IN THEIR SOLUTIONS FOR THE EXTENDED PERIOD THAN THEY
HAVE IN PREVIOUS RUNS.

FLOW GENERALLY BECOMES MORE PROGRESSIVE WITH TIME. WEAK NORTHERN
STREAM OF A PACIFIC TROUGH WILL BE OVER THE REGION ON THU. THIS
WILL BE FOLLOWED BY A SHORTWAVE RIDGE ON FRI AND ANOTHER WEAK
TROUGH FOR SAT. WENT WITH SUPER BLEND POPS FOR THIS PERIOD WHERE
MOISTURE AFFECTS MAINLY THE MOUNTAINS. A STRONG PACIFIC JET WILL
MOVE INTO THE REGION LATE IN THE PERIOD WHICH RESULTS IN A FAST
WNW FLOW OVERTAKING THE AREA BEGINNING ON SUN. ENERGY WILL MOVE
THROUGH THIS FLOW ALONG WITH PERIODS OF PACIFIC MOISTURE. GEFS
SHOWED AN ATMOSPHERIC RIVER WILL AFFECT THE REGION SUN INTO MON
WHICH WILL CONTRIBUTE TO PRECIPITATION CHANCES. HAVE INCREASED
POPS OVER THE AREA BEGINNING ON SUN. MAY HAVE GAP WIND ISSUES SAT
NIGHT INTO MON AS MODELS AGREED ON STRONG LEE TROUGHING OVER THE
AREA. WILL CONTINUE TO HAVE STRONG WINDS IN THE FORECAST FOR THE
GAP AREAS. THE MODELS WERE IN GOOD AGREEMENT WITH TEMPERATURES
THROUGH THE EXTENDED AND SHOWED ABOVE NORMAL READINGS. ARTHUR
&&

.AVIATION...

LIFR TO VLIFR CONDITIONS IN STRATUS AND FOG WILL PERSIST FROM
ROSEBUD COUNTY W THROUGH MOST OF THE DAY. LATEST SHORT RANGE
GUIDANCE SHOWS LITTLE IMPROVEMENT. TONIGHT CONDITIONS WILL LIKELY
DEGRADE FROM ANY IMPROVEMENTS TODAY. MOUNTAIN OBSCURATIONS WILL
BE WIDESPREAD THROUGH TONIGHT. REIMER

&&

.PRELIMINARY POINT TEMP/POPS...

    TDY WED     THU     FRI     SAT     SUN     MON
-------------------------------------------------------
BIL 027 020/036 022/039 023/039 026/042 025/043 035/045
    0/B 11/B    01/B    10/U    11/B    12/W    23/W
LVM 029 024/042 023/042 022/041 026/043 026/043 033/045
    1/E 22/J    11/E    11/U    11/B    13/W    33/W
HDN 029 014/033 015/037 017/038 019/040 019/041 028/043
    0/E 01/B    01/B    10/U    01/B    11/B    23/W
MLS 027 015/030 017/036 019/037 018/038 022/039 028/042
    0/E 01/B    01/B    10/U    01/U    11/U    23/W
4BQ 030 015/033 016/040 018/040 016/041 020/042 027/043
    0/E 02/J    01/B    10/U    01/U    11/B    23/W
BHK 024 012/028 015/035 019/037 016/038 020/039 025/041
    0/E 02/J    11/B    11/U    01/U    11/B    23/W
SHR 028 015/036 016/038 016/038 019/040 019/041 026/042
    0/B 01/B    01/B    10/U    01/B    12/J    33/W

&&

.BYZ WATCHES/WARNINGS/ADVISORIES...
MT...DENSE FOG ADVISORY IN EFFECT UNTIL 2 PM MST THIS AFTERNOON
      FOR ZONES 28-34-41-63.
WY...NONE.

&&

$$
WEATHER.GOV/BILLINGS




000
FXUS65 KBYZ 161803
AFDBYZ

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BILLINGS MT
1103 AM MST TUE DEC 16 2014

.UPDATE...
A QUICK UPDATE TO EXTEND THE DENSE FOG ADVISORY FOR STILLWATER
SWEET GRASS AND WHEATLAND COUNTY THROUGH 2 PM THIS AFTERNOON.
DENSE FOG WITH VISIBILITY LESS THAN A 1/4 MILES IS CONTINUING
OVER THESE AREAS AS A RESULT OF A MOIST UPSLOPE SURFACE FLOW. WILL
KEEP AREAS OF FOG GOING FOR SHERIDAN NORTHWARD THROUGH BILLINGS
AND ROUNDUP INTO THE EARLY AFTERNOON HOURS ALSO. NO OTHER CHANGES
MADE TO THE FORECAST. RICHMOND

&&

.SHORT TERM...VALID FOR TDY AND WED...

MAIN FORECAST PROBLEM FOR THE SHORT TERM CONCERNS CONSIDERABLE
AREAS OF FOG ACROSS THE FORECAST AREA...PARTICULARLY IN THE LOWER
ELEVATIONS OF THE WESTERN ZONES. THE PATTERN FAVORS THIS TO
CONTINUE WITH A RIDGE ALOFT AND SURFACE LOW PRESSURE TO OUR
WEST/SOUTHWEST THIS IS KEEPING A SOUTHEAST LOW LEVEL FLOW
UPSLOPING INTO SOUTH CENTRAL MONTANA. LOCAL OBSERVATIONS SHOW A
QUARTER MILE VISIBILITY OR LESS IN AREAS JUST WEST OF BILLINGS TO
LIVINGSTON AND UP TO JUDITH GAP. MESOSCALE CROSS SECTIONS SHOW
THIS PERSISTING THROUGH MUCH OF THE MORNING FOR THIS AREA...AND
PERHAPS EVEN INTO THE AFTERNOON FOR PARK COUNTY AROUND LIVINGSTON.
THIS WILL ALSO TEND TO PREVENT MUCH IF ANY SOLAR RADIATION FOR
MUCH OF THE DAY AND SINCE MOS GUIDANCE IS NOT TAKING IT INTO
ACCOUNT I WILL BE SURE TO UNDERCUT GUIDANCE IN THESE AREAS. MAIN
MESSAGE...FOGGY AND CONTINUED CHILLY MOST LOCATIONS TODAY.

DENSE FOG ADVISORY...ISSUED ACROSS AREAS GENERALLY FROM LIVINGSTON
TO BIG TIMBER AND UP TO JUDITH GAP WHERE OBSERVATIONS INDICATE
PERSISTENT DENSE FOG. LOCALLY ICY ROADS WILL MAKE THIS EVEN MORE
DANGEROUS. AS MENTIONED BEFORE PROGGS SUGGEST THE WIDESPREAD FOG
WILL LINGER IN THESE AREAS UNTIL ABOUT 18Z.

IN THE MEANTIME...THE 500MB RIDGE BUILDING OVER US NOW WILL
QUICKLY BREAK DOWN LATE TODAY AND TONIGHT AS ANOTHER BROAD SPLIT
FLOW TROUGH MOVES INTO THE WESTERN UNITED STATES. A WEAKER SHORT
WAVE IN THE MEAN FLOW WILL SPLIT FROM THE SOUTHERN BRANCH AND
TRACK OVER OUR REGION TONIGHT AND INTO WEDNESDAY. QPF PROGGS ARE
NOT IMPRESSIVE BUT SEEMS PRUDENT TO BUMP UP SOME OF THE POPS NOW
FOR THE HIGH COUNTRY. WE MAY SEE SOME FLURRIES OR LIGHT SNOW IN
THE EAST AS IT MOVES THROUGH WEDNESDAY MORNING AS WELL. LOOK FOR A
MODEST WARM UP TO AROUND SEASONAL AVERAGES FOR WEDNESDAY. BT

.LONG TERM...VALID FOR THU...FRI...SAT...SUN...MON...

ENSEMBLE FORECASTS FROM THE GFS AND ECMWF WERE SHOWING MORE
CONFIDENCE IN THEIR SOLUTIONS FOR THE EXTENDED PERIOD THAN THEY
HAVE IN PREVIOUS RUNS.

FLOW GENERALLY BECOMES MORE PROGRESSIVE WITH TIME. WEAK NORTHERN
STREAM OF A PACIFIC TROUGH WILL BE OVER THE REGION ON THU. THIS
WILL BE FOLLOWED BY A SHORTWAVE RIDGE ON FRI AND ANOTHER WEAK
TROUGH FOR SAT. WENT WITH SUPER BLEND POPS FOR THIS PERIOD WHERE
MOISTURE AFFECTS MAINLY THE MOUNTAINS. A STRONG PACIFIC JET WMP/POPS...

    TDY WED     THU     FRI     SAT     SUN     MON
-------------------------------------------------------
BIL 027 020/036 022/039 023/039 026/042 025/043 035/045
    0/B 11/B    01/B    10/U    11/B    12/W    23/W
LVM 029 024/042 023/042 022/041 026/043 026/043 033/045
    1/E 22/J    11/E    11/U    11/B    13/W    33/W
HDN 029 014/033 015/037 017/038 019/040 019/041 028/043
    0/E 01/B    01/B    10/U    01/B    11/B    23/W
MLS 027 015/030 017/036 019/037 018/038 022/039 028/042
    0/E 01/B    01/B    10/U    01/U    11/U    23/W
4BQ 030 015/033 016/040 018/040 016/041 020/042 027/043
    0/E 02/J    01/B    10/U    01/U    11/B    23/W
BHK 024 012/028 015/035 019/037 016/038 020/039 025/041
    0/E 02/J    11/B    11/U    01/U    11/B    23/W
SHR 028 015/036 016/038 016/038 019/040 019/041 026/042
    0/B 01/B    01/B    10/U    01/B    12/J    33/W

&&

.BYZ WATCHES/WARNINGS/ADVISORIES...
MT...DENSE FOG ADVISORY IN EFFECT UNTIL 2 PM MST THILL
MOVE INTO THE REGION LATE IN THE PERIOD WHICH RESULTS IN A FAST
WNW FLOW OVERTAKING THE AREA BEGINNING ON SUN. ENERGY WILL MOVE
THROUGH THIS FLOW ALONG WITH PERIODS OF PACIFIC MOISTURE. GEFS
SHOWED AN ATMOSPHERIC RIVER WILL AFFECT THE REGION SUN INTO MON
WHICH WILL CONTRIBUTE TO PRECIPITATION CHANCES. HAVE INCREASED
POPS OVER THE AREA BEGINNING ON SUN. MAY HAVE GAP WIND ISSUES SAT
NIGHT INTO MON AS MODELS AGREED ON STRONG LEE TROUGHING OVER THE
AREA. WILL CONTINUE TO HAVE STRONG WINDS IN THE FORECAST FOR THE
GAP AREAS. THE MODELS WERE IN GOOD AGREEMENT WITH TEMPERATURES
THROUGH THE EXTENDED AND SHOWED ABOVE NORMAL READINGS. ARTHUR
&&

.AVIATION...

LIFR TO VLIFR CONDITIONS IN STRATUS AND FOG WILL PERSIST FROM
ROSEBUD COUNTY W THROUGH MOST OF THE DAY. LATEST SHORT RANGE
GUIDANCE SHOWS LITTLE IMPROVEMENT. TONIGHT CONDITIONS WILL LIKELY
DEGRADE FROM ANY IMPROVEMENTS TODAY. MOUNTAIN OBSCURATIONS WILL
BE WIDESPREAD THROUGH TONIGHT. REIMER

&&

.PRELIMINARY POINT TEIS AFTERNOON
      FOR ZONES 28-34-41-63.
WY...NONE.

&&

$$
WEATHER.GOV/BILLINGS



000
FXUS65 KTFX 161749
AFDTFX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREAT FALLS MT
1050 AM MST Tue Dec 16 2014

UPDATED AVIATION DISCUSSION

.UPDATE...
Minor update to the forecast for today. With light wind, and layer
of clouds, believe atmospheric mixing will be minimal and
temperatures will have a tough time warming today. Widespread
areas of fog continue. Freezing Fog Advisory remains in place and
may need to be extended. Pulled back on afternoon high
temperatures across much of north central and central Montana.
Also added mention of Freezing Fog redeveloping later this afternoon
and this evening.

Remainder of forecast on track with areas of snow showers
developing over southwest and working into central Montana later
today and tonight.
&&

.AVIATION...
UPDATED 1750Z.
This is a very low confidence forecast with respect to ceilings and
visibilities. Do have fair confidence that areas of light snow will
spread into southwest Montana late this afternoon then reach the
Canadian border early Wednesday morning. Conditions for KGTF and
KCTB and KHVR could range from VFR to LIFR at anytime at least into
early Wednesday morning. Then for KBZN and KHLN and KLWT conditions
could range from VFR to IFR at any time after 00Z. Also have fair
confidence that conditions will be mostly VFR at 18Z Wednesday. Blank

&&

.PREV DISCUSSION...
/ISSUED 510 AM MST Tue Dec 16 2014/

Today through Thursday...Forecast for the short term period is
expected to remain foggy this morning. Have expanded the Freezing
Fog Advisory to include Cascade and Judith Basin Counties as well
as the Rocky Mountain based on latest observations and SPORT night
time microphysics RGB imagery. Shortwave energy is still on track
to push into southwest Montana today and then into central Montana
overnight. Have increased PoPs across portions of the forecast
area based upon NAM model run but do not anticipated that snowfall
will be widespread enough or heavy enough to require any type of
highlights. Temperatures will remain near or below seasonal
averages for this time of year but I have undercut office-derived
SuperBlend temperature guidance for today and Wednesday given poor
performance on Monday. Expect another lull in clouds and
precipitation Wednesday night into Thursday before the progressive
pattern aloft brings another shortwave into western portions of
the forecast area Thursday afternoon. mpj

Thursday Night through Tuesday...A weak upper level ridge of high
pressure will keep the forecast area mostly dry Thursday night and
Friday. A shortwave trough will then move into the area Friday night
into Saturday, bringing an increased chance of mountain snow.
However, breezy westerly downslope winds will keep the plains dry.
The weather pattern will change somewhat beginning on Sunday. An
upper level ridge of high pressure will strengthen off the
California coast and an upper level trough of low pressure will
deepen from Hudson Bay into the Great Lakes. This will put Montana
under the influence of a strong northwesterly flow aloft. The
strongest winds aloft (60 to 70 kt at 700 mb) will occur Sunday into
Monday with the passage of a disturbance embedded in the flow. This
set-up will bring gusty westerly downslope winds to much of the
area, but especially over the plains of north central Montana. In
fact, some areas along the Rocky Mountain Front could approach High
Wind criteria (40 mph sustained/58 mph gusts). Confidence is
increasing that High Wind highlights may be needed for this event.
There is also significant moisture with this disturbance, so have
increased the chance for precipitation out onto the plains. Although
the winds will decrease somewhat after the passage of the
disturbance, the northwesterly flow aloft will remain fairly moist,
so have kept the chance for precipitation above climatological
normals across the area into Tuesday. The breezy winds throughout
the period will keep temperatures around 10 degrees above normal.
The warmest day of the period appears to be Monday, when most lower
elevation locations should get well into the 40s.
Coulston

&&

.PRELIMINARY POINT TEMPS/POPS...
GTF  28  22  36  24 /   0  20  30  10
CTB  25  17  34  21 /   0  10  10  10
HLN  30  20  32  19 /  10  30  20  10
BZN  29  19  33  15 /  10  30  20  10
WEY  29  18  31  14 /  40  50  40  20
DLN  31  21  34  19 /  20  30  10  10
HVR  26  15  30  20 /   0  10  20  10
LWT  30  22  37  21 /   0  20  20  10

&&

.TFX WATCHES/WARNINGS/ADVISORIES...
FREEZING FOG ADVISORY until 11 AM MST this morning Cascade...
Eastern Glacier...Eastern Pondera...Eastern Teton...Judith
Basin...Northern Rocky Mountain Front...Southern Rocky Mountain
Front...Toole.

&&

$$

weather.gov/greatfalls
www.twitter.com/NWSGreatFalls
www.facebook.com/NWSGreatFalls







000
FXUS65 KTFX 161749
AFDTFX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREAT FALLS MT
1050 AM MST Tue Dec 16 2014

UPDATED AVIATION DISCUSSION

.UPDATE...
Minor update to the forecast for today. With light wind, and layer
of clouds, believe atmospheric mixing will be minimal and
temperatures will have a tough time warming today. Widespread
areas of fog continue. Freezing Fog Advisory remains in place and
may need to be extended. Pulled back on afternoon high
temperatures across much of north central and central Montana.
Also added mention of Freezing Fog redeveloping later this afternoon
and this evening.

Remainder of forecast on track with areas of snow showers
developing over southwest and working into central Montana later
today and tonight.
&&

.AVIATION...
UPDATED 1750Z.
This is a very low confidence forecast with respect to ceilings and
visibilities. Do have fair confidence that areas of light snow will
spread into southwest Montana late this afternoon then reach the
Canadian border early Wednesday morning. Conditions for KGTF and
KCTB and KHVR could range from VFR to LIFR at anytime at least into
early Wednesday morning. Then for KBZN and KHLN and KLWT conditions
could range from VFR to IFR at any time after 00Z. Also have fair
confidence that conditions will be mostly VFR at 18Z Wednesday. Blank

&&

.PREV DISCUSSION...
/ISSUED 510 AM MST Tue Dec 16 2014/

Today through Thursday...Forecast for the short term period is
expected to remain foggy this morning. Have expanded the Freezing
Fog Advisory to include Cascade and Judith Basin Counties as well
as the Rocky Mountain based on latest observations and SPORT night
time microphysics RGB imagery. Shortwave energy is still on track
to push into southwest Montana today and then into central Montana
overnight. Have increased PoPs across portions of the forecast
area based upon NAM model run but do not anticipated that snowfall
will be widespread enough or heavy enough to require any type of
highlights. Temperatures will remain near or below seasonal
averages for this time of year but I have undercut office-derived
SuperBlend temperature guidance for today and Wednesday given poor
performance on Monday. Expect another lull in clouds and
precipitation Wednesday night into Thursday before the progressive
pattern aloft brings another shortwave into western portions of
the forecast area Thursday afternoon. mpj

Thursday Night through Tuesday...A weak upper level ridge of high
pressure will keep the forecast area mostly dry Thursday night and
Friday. A shortwave trough will then move into the area Friday night
into Saturday, bringing an increased chance of mountain snow.
However, breezy westerly downslope winds will keep the plains dry.
The weather pattern will change somewhat beginning on Sunday. An
upper level ridge of high pressure will strengthen off the
California coast and an upper level trough of low pressure will
deepen from Hudson Bay into the Great Lakes. This will put Montana
under the influence of a strong northwesterly flow aloft. The
strongest winds aloft (60 to 70 kt at 700 mb) will occur Sunday into
Monday with the passage of a disturbance embedded in the flow. This
set-up will bring gusty westerly downslope winds to much of the
area, but especially over the plains of north central Montana. In
fact, some areas along the Rocky Mountain Front could approach High
Wind criteria (40 mph sustained/58 mph gusts). Confidence is
increasing that High Wind highlights may be needed for this event.
There is also significant moisture with this disturbance, so have
increased the chance for precipitation out onto the plains. Although
the winds will decrease somewhat after the passage of the
disturbance, the northwesterly flow aloft will remain fairly moist,
so have kept the chance for precipitation above climatological
normals across the area into Tuesday. The breezy winds throughout
the period will keep temperatures around 10 degrees above normal.
The warmest day of the period appears to be Monday, when most lower
elevation locations should get well into the 40s.
Coulston

&&

.PRELIMINARY POINT TEMPS/POPS...
GTF  28  22  36  24 /   0  20  30  10
CTB  25  17  34  21 /   0  10  10  10
HLN  30  20  32  19 /  10  30  20  10
BZN  29  19  33  15 /  10  30  20  10
WEY  29  18  31  14 /  40  50  40  20
DLN  31  21  34  19 /  20  30  10  10
HVR  26  15  30  20 /   0  10  20  10
LWT  30  22  37  21 /   0  20  20  10

&&

.TFX WATCHES/WARNINGS/ADVISORIES...
FREEZING FOG ADVISORY until 11 AM MST this morning Cascade...
Eastern Glacier...Eastern Pondera...Eastern Teton...Judith
Basin...Northern Rocky Mountain Front...Southern Rocky Mountain
Front...Toole.

&&

$$

weather.gov/greatfalls
www.twitter.com/NWSGreatFalls
www.facebook.com/NWSGreatFalls







000
FXUS65 KTFX 161749
AFDTFX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREAT FALLS MT
1050 AM MST Tue Dec 16 2014

UPDATED AVIATION DISCUSSION

.UPDATE...
Minor update to the forecast for today. With light wind, and layer
of clouds, believe atmospheric mixing will be minimal and
temperatures will have a tough time warming today. Widespread
areas of fog continue. Freezing Fog Advisory remains in place and
may need to be extended. Pulled back on afternoon high
temperatures across much of north central and central Montana.
Also added mention of Freezing Fog redeveloping later this afternoon
and this evening.

Remainder of forecast on track with areas of snow showers
developing over southwest and working into central Montana later
today and tonight.
&&

.AVIATION...
UPDATED 1750Z.
This is a very low confidence forecast with respect to ceilings and
visibilities. Do have fair confidence that areas of light snow will
spread into southwest Montana late this afternoon then reach the
Canadian border early Wednesday morning. Conditions for KGTF and
KCTB and KHVR could range from VFR to LIFR at anytime at least into
early Wednesday morning. Then for KBZN and KHLN and KLWT conditions
could range from VFR to IFR at any time after 00Z. Also have fair
confidence that conditions will be mostly VFR at 18Z Wednesday. Blank

&&

.PREV DISCUSSION...
/ISSUED 510 AM MST Tue Dec 16 2014/

Today through Thursday...Forecast for the short term period is
expected to remain foggy this morning. Have expanded the Freezing
Fog Advisory to include Cascade and Judith Basin Counties as well
as the Rocky Mountain based on latest observations and SPORT night
time microphysics RGB imagery. Shortwave energy is still on track
to push into southwest Montana today and then into central Montana
overnight. Have increased PoPs across portions of the forecast
area based upon NAM model run but do not anticipated that snowfall
will be widespread enough or heavy enough to require any type of
highlights. Temperatures will remain near or below seasonal
averages for this time of year but I have undercut office-derived
SuperBlend temperature guidance for today and Wednesday given poor
performance on Monday. Expect another lull in clouds and
precipitation Wednesday night into Thursday before the progressive
pattern aloft brings another shortwave into western portions of
the forecast area Thursday afternoon. mpj

Thursday Night through Tuesday...A weak upper level ridge of high
pressure will keep the forecast area mostly dry Thursday night and
Friday. A shortwave trough will then move into the area Friday night
into Saturday, bringing an increased chance of mountain snow.
However, breezy westerly downslope winds will keep the plains dry.
The weather pattern will change somewhat beginning on Sunday. An
upper level ridge of high pressure will strengthen off the
California coast and an upper level trough of low pressure will
deepen from Hudson Bay into the Great Lakes. This will put Montana
under the influence of a strong northwesterly flow aloft. The
strongest winds aloft (60 to 70 kt at 700 mb) will occur Sunday into
Monday with the passage of a disturbance embedded in the flow. This
set-up will bring gusty westerly downslope winds to much of the
area, but especially over the plains of north central Montana. In
fact, some areas along the Rocky Mountain Front could approach High
Wind criteria (40 mph sustained/58 mph gusts). Confidence is
increasing that High Wind highlights may be needed for this event.
There is also significant moisture with this disturbance, so have
increased the chance for precipitation out onto the plains. Although
the winds will decrease somewhat after the passage of the
disturbance, the northwesterly flow aloft will remain fairly moist,
so have kept the chance for precipitation above climatological
normals across the area into Tuesday. The breezy winds throughout
the period will keep temperatures around 10 degrees above normal.
The warmest day of the period appears to be Monday, when most lower
elevation locations should get well into the 40s.
Coulston

&&

.PRELIMINARY POINT TEMPS/POPS...
GTF  28  22  36  24 /   0  20  30  10
CTB  25  17  34  21 /   0  10  10  10
HLN  30  20  32  19 /  10  30  20  10
BZN  29  19  33  15 /  10  30  20  10
WEY  29  18  31  14 /  40  50  40  20
DLN  31  21  34  19 /  20  30  10  10
HVR  26  15  30  20 /   0  10  20  10
LWT  30  22  37  21 /   0  20  20  10

&&

.TFX WATCHES/WARNINGS/ADVISORIES...
FREEZING FOG ADVISORY until 11 AM MST this morning Cascade...
Eastern Glacier...Eastern Pondera...Eastern Teton...Judith
Basin...Northern Rocky Mountain Front...Southern Rocky Mountain
Front...Toole.

&&

$$

weather.gov/greatfalls
www.twitter.com/NWSGreatFalls
www.facebook.com/NWSGreatFalls







000
FXUS65 KTFX 161749
AFDTFX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREAT FALLS MT
1050 AM MST Tue Dec 16 2014

UPDATED AVIATION DISCUSSION

.UPDATE...
Minor update to the forecast for today. With light wind, and layer
of clouds, believe atmospheric mixing will be minimal and
temperatures will have a tough time warming today. Widespread
areas of fog continue. Freezing Fog Advisory remains in place and
may need to be extended. Pulled back on afternoon high
temperatures across much of north central and central Montana.
Also added mention of Freezing Fog redeveloping later this afternoon
and this evening.

Remainder of forecast on track with areas of snow showers
developing over southwest and working into central Montana later
today and tonight.
&&

.AVIATION...
UPDATED 1750Z.
This is a very low confidence forecast with respect to ceilings and
visibilities. Do have fair confidence that areas of light snow will
spread into southwest Montana late this afternoon then reach the
Canadian border early Wednesday morning. Conditions for KGTF and
KCTB and KHVR could range from VFR to LIFR at anytime at least into
early Wednesday morning. Then for KBZN and KHLN and KLWT conditions
could range from VFR to IFR at any time after 00Z. Also have fair
confidence that conditions will be mostly VFR at 18Z Wednesday. Blank

&&

.PREV DISCUSSION...
/ISSUED 510 AM MST Tue Dec 16 2014/

Today through Thursday...Forecast for the short term period is
expected to remain foggy this morning. Have expanded the Freezing
Fog Advisory to include Cascade and Judith Basin Counties as well
as the Rocky Mountain based on latest observations and SPORT night
time microphysics RGB imagery. Shortwave energy is still on track
to push into southwest Montana today and then into central Montana
overnight. Have increased PoPs across portions of the forecast
area based upon NAM model run but do not anticipated that snowfall
will be widespread enough or heavy enough to require any type of
highlights. Temperatures will remain near or below seasonal
averages for this time of year but I have undercut office-derived
SuperBlend temperature guidance for today and Wednesday given poor
performance on Monday. Expect another lull in clouds and
precipitation Wednesday night into Thursday before the progressive
pattern aloft brings another shortwave into western portions of
the forecast area Thursday afternoon. mpj

Thursday Night through Tuesday...A weak upper level ridge of high
pressure will keep the forecast area mostly dry Thursday night and
Friday. A shortwave trough will then move into the area Friday night
into Saturday, bringing an increased chance of mountain snow.
However, breezy westerly downslope winds will keep the plains dry.
The weather pattern will change somewhat beginning on Sunday. An
upper level ridge of high pressure will strengthen off the
California coast and an upper level trough of low pressure will
deepen from Hudson Bay into the Great Lakes. This will put Montana
under the influence of a strong northwesterly flow aloft. The
strongest winds aloft (60 to 70 kt at 700 mb) will occur Sunday into
Monday with the passage of a disturbance embedded in the flow. This
set-up will bring gusty westerly downslope winds to much of the
area, but especially over the plains of north central Montana. In
fact, some areas along the Rocky Mountain Front could approach High
Wind criteria (40 mph sustained/58 mph gusts). Confidence is
increasing that High Wind highlights may be needed for this event.
There is also significant moisture with this disturbance, so have
increased the chance for precipitation out onto the plains. Although
the winds will decrease somewhat after the passage of the
disturbance, the northwesterly flow aloft will remain fairly moist,
so have kept the chance for precipitation above climatological
normals across the area into Tuesday. The breezy winds throughout
the period will keep temperatures around 10 degrees above normal.
The warmest day of the period appears to be Monday, when most lower
elevation locations should get well into the 40s.
Coulston

&&

.PRELIMINARY POINT TEMPS/POPS...
GTF  28  22  36  24 /   0  20  30  10
CTB  25  17  34  21 /   0  10  10  10
HLN  30  20  32  19 /  10  30  20  10
BZN  29  19  33  15 /  10  30  20  10
WEY  29  18  31  14 /  40  50  40  20
DLN  31  21  34  19 /  20  30  10  10
HVR  26  15  30  20 /   0  10  20  10
LWT  30  22  37  21 /   0  20  20  10

&&

.TFX WATCHES/WARNINGS/ADVISORIES...
FREEZING FOG ADVISORY until 11 AM MST this morning Cascade...
Eastern Glacier...Eastern Pondera...Eastern Teton...Judith
Basin...Northern Rocky Mountain Front...Southern Rocky Mountain
Front...Toole.

&&

$$

weather.gov/greatfalls
www.twitter.com/NWSGreatFalls
www.facebook.com/NWSGreatFalls







000
FXUS65 KTFX 161726
AFDTFX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREAT FALLS MT
1026 AM MST Tue Dec 16 2014

.UPDATE...
Minor update to the forecast for today. With light wind, and layer
of clouds, believe atmospheric mixing will be minimal and
temperatures will have a tough time warming today. Widespread
areas of fog continue. Freezing Fog Advisory remains in place and
may need to be extended. Pulled back on afternoon high
temperatures across much of north central and central Montana.
Also added mention of Freezing Fog redeveloping later this afternoon
and this evening.

Remainder of forecast on track with areas of snow showers
developing over southwest and working into central Montana later
today and tonight.
&&

.AVIATION...
UPDATED 1210Z.
Low clouds with areas of dense fog will likely begin to erode
somewhat after 16Z across the plains of north central today.
Ceilings will mostly be IFR/LIFR, but the dense fog over the
western plains (including KGTF KCTB) is causing VLIFR conditions.
Conditions should improve in the west first, then ceilings will
gradually lift and clouds will break up after 18Z. However, KLWT is
out of the fog/low clouds at this time, and they will likely stay
that way. A disturbance will move northeast into the area after 00Z,
bringing increasing high and mid level cloudiness from the southwest
after 18Z, then more mid level cloudiness and a chance of snow after
03Z in the southwest and after 06Z over central Montana. Occasional
MVFR conditions are possible with any snow.
Coulston

&&

.PREV DISCUSSION...
/ISSUED 510 AM MST Tue Dec 16 2014/

Today through Thursday...Forecast for the short term period is
expected to remain foggy this morning. Have expanded the Freezing
Fog Advisory to include Cascade and Judith Basin Counties as well
as the Rocky Mountain based on latest observations and SPORT night
time microphysics RGB imagery. Shortwave energy is still on track
to push into southwest Montana today and then into central Montana
overnight. Have increased PoPs across portions of the forecast
area based upon NAM model run but do not anticipated that snowfall
will be widespread enough or heavy enough to require any type of
highlights. Temperatures will remain near or below seasonal
averages for this time of year but I have undercut office-derived
SuperBlend temperature guidance for today and Wednesday given poor
performance on Monday. Expect another lull in clouds and
precipitation Wednesday night into Thursday before the progressive
pattern aloft brings another shortwave into western portions of
the forecast area Thursday afternoon. mpj

Thursday Night through Tuesday...A weak upper level ridge of high
pressure will keep the forecast area mostly dry Thursday night and
Friday. A shortwave trough will then move into the area Friday night
into Saturday, bringing an increased chance of mountain snow.
However, breezy westerly downslope winds will keep the plains dry.
The weather pattern will change somewhat beginning on Sunday. An
upper level ridge of high pressure will strengthen off the
California coast and an upper level trough of low pressure will
deepen from Hudson Bay into the Great Lakes. This will put Montana
under the influence of a strong northwesterly flow aloft. The
strongest winds aloft (60 to 70 kt at 700 mb) will occur Sunday into
Monday with the passage of a disturbance embedded in the flow. This
set-up will bring gusty westerly downslope winds to much of the
area, but especially over the plains of north central Montana. In
fact, some areas along the Rocky Mountain Front could approach High
Wind criteria (40 mph sustained/58 mph gusts). Confidence is
increasing that High Wind highlights may be needed for this event.
There is also significant moisture with this disturbance, so have
increased the chance for precipitation out onto the plains. Although
the winds will decrease somewhat after the passage of the
disturbance, the northwesterly flow aloft will remain fairly moist,
so have kept the chance for precipitation above climatological
normals across the area into Tuesday. The breezy winds throughout
the period will keep temperatures around 10 degrees above normal.
The warmest day of the period appears to be Monday, when most lower
elevation locations should get well into the 40s.
Coulston

&&

.PRELIMINARY POINT TEMPS/POPS...
GTF  28  22  36  24 /   0  20  30  10
CTB  25  17  34  21 /   0  10  10  10
HLN  30  20  32  19 /  10  30  20  10
BZN  29  19  33  15 /  10  30  20  10
WEY  29  18  31  14 /  40  50  40  20
DLN  31  21  34  19 /  20  30  10  10
HVR  26  15  30  20 /   0  10  20  10
LWT  30  22  37  21 /   0  20  20  10

&&

.TFX WATCHES/WARNINGS/ADVISORIES...
FREEZING FOG ADVISORY until 11 AM MST this morning Cascade...
Eastern Glacier...Eastern Pondera...Eastern Teton...Judith
Basin...Northern Rocky Mountain Front...Southern Rocky Mountain
Front...Toole.

&&

$$

weather.gov/greatfalls
www.twitter.com/NWSGreatFalls
www.facebook.com/NWSGreatFalls





000
FXUS65 KTFX 161726
AFDTFX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREAT FALLS MT
1026 AM MST Tue Dec 16 2014

.UPDATE...
Minor update to the forecast for today. With light wind, and layer
of clouds, believe atmospheric mixing will be minimal and
temperatures will have a tough time warming today. Widespread
areas of fog continue. Freezing Fog Advisory remains in place and
may need to be extended. Pulled back on afternoon high
temperatures across much of north central and central Montana.
Also added mention of Freezing Fog redeveloping later this afternoon
and this evening.

Remainder of forecast on track with areas of snow showers
developing over southwest and working into central Montana later
today and tonight.
&&

.AVIATION...
UPDATED 1210Z.
Low clouds with areas of dense fog will likely begin to erode
somewhat after 16Z across the plains of north central today.
Ceilings will mostly be IFR/LIFR, but the dense fog over the
western plains (including KGTF KCTB) is causing VLIFR conditions.
Conditions should improve in the west first, then ceilings will
gradually lift and clouds will break up after 18Z. However, KLWT is
out of the fog/low clouds at this time, and they will likely stay
that way. A disturbance will move northeast into the area after 00Z,
bringing increasing high and mid level cloudiness from the southwest
after 18Z, then more mid level cloudiness and a chance of snow after
03Z in the southwest and after 06Z over central Montana. Occasional
MVFR conditions are possible with any snow.
Coulston

&&

.PREV DISCUSSION...
/ISSUED 510 AM MST Tue Dec 16 2014/

Today through Thursday...Forecast for the short term period is
expected to remain foggy this morning. Have expanded the Freezing
Fog Advisory to include Cascade and Judith Basin Counties as well
as the Rocky Mountain based on latest observations and SPORT night
time microphysics RGB imagery. Shortwave energy is still on track
to push into southwest Montana today and then into central Montana
overnight. Have increased PoPs across portions of the forecast
area based upon NAM model run but do not anticipated that snowfall
will be widespread enough or heavy enough to require any type of
highlights. Temperatures will remain near or below seasonal
averages for this time of year but I have undercut office-derived
SuperBlend temperature guidance for today and Wednesday given poor
performance on Monday. Expect another lull in clouds and
precipitation Wednesday night into Thursday before the progressive
pattern aloft brings another shortwave into western portions of
the forecast area Thursday afternoon. mpj

Thursday Night through Tuesday...A weak upper level ridge of high
pressure will keep the forecast area mostly dry Thursday night and
Friday. A shortwave trough will then move into the area Friday night
into Saturday, bringing an increased chance of mountain snow.
However, breezy westerly downslope winds will keep the plains dry.
The weather pattern will change somewhat beginning on Sunday. An
upper level ridge of high pressure will strengthen off the
California coast and an upper level trough of low pressure will
deepen from Hudson Bay into the Great Lakes. This will put Montana
under the influence of a strong northwesterly flow aloft. The
strongest winds aloft (60 to 70 kt at 700 mb) will occur Sunday into
Monday with the passage of a disturbance embedded in the flow. This
set-up will bring gusty westerly downslope winds to much of the
area, but especially over the plains of north central Montana. In
fact, some areas along the Rocky Mountain Front could approach High
Wind criteria (40 mph sustained/58 mph gusts). Confidence is
increasing that High Wind highlights may be needed for this event.
There is also significant moisture with this disturbance, so have
increased the chance for precipitation out onto the plains. Although
the winds will decrease somewhat after the passage of the
disturbance, the northwesterly flow aloft will remain fairly moist,
so have kept the chance for precipitation above climatological
normals across the area into Tuesday. The breezy winds throughout
the period will keep temperatures around 10 degrees above normal.
The warmest day of the period appears to be Monday, when most lower
elevation locations should get well into the 40s.
Coulston

&&

.PRELIMINARY POINT TEMPS/POPS...
GTF  28  22  36  24 /   0  20  30  10
CTB  25  17  34  21 /   0  10  10  10
HLN  30  20  32  19 /  10  30  20  10
BZN  29  19  33  15 /  10  30  20  10
WEY  29  18  31  14 /  40  50  40  20
DLN  31  21  34  19 /  20  30  10  10
HVR  26  15  30  20 /   0  10  20  10
LWT  30  22  37  21 /   0  20  20  10

&&

.TFX WATCHES/WARNINGS/ADVISORIES...
FREEZING FOG ADVISORY until 11 AM MST this morning Cascade...
Eastern Glacier...Eastern Pondera...Eastern Teton...Judith
Basin...Northern Rocky Mountain Front...Southern Rocky Mountain
Front...Toole.

&&

$$

weather.gov/greatfalls
www.twitter.com/NWSGreatFalls
www.facebook.com/NWSGreatFalls






000
FXUS65 KBYZ 161701
AFDBYZ

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BILLINGS MT
1001 AM MST TUE DEC 16 2014

.UPDATE...
AREAS OF FOG STILL LINGER OVER THE AREA THIS MORNING. WILL
CONTINUE TO KEEP FOG IN THE FORECAST THROUGH 19Z. IR SATELLITE
SHOWING MID LEVEL CLOUD DECK MOVING INTO OUR WESTERN ZONES AT 16Z
AND THIS HAS ALLOWED FOG AND LOW STRATUS DECK TO DISSIPATE IN
LIVINGSTON. WILL GO AHEAD AND DROP THE DENSE FOG ADVISORY FOR
KLVM. VISIBILITY STILL DOWN TO A 1/4 MILES FROM BIG TIMBER TO
EXPECT FOG TO SLOWLY DISSIPATE BY LATE MORNING OVER THESE AREAS
AS WELL AS IN THE BILLINGS AREA WITH MID LEVEL CLOUD DECK MOVING
IN. DID BACK OFF ON HIGH TEMPERATURES IN THE WEST A FEW DEGREES
WITH EXPECTED CLOUD COVER TODAY.

FOG MAY REDEVELOP OVER THE ENTIRE AREA TONIGHT AND WILL BE MAINLY
FROM HYSHAM WESTWARD. WILL ADDRESS THIS WITH THE AFTERNOON
FORECAST PACKAGE. RICHMOND

&&

.SHORT TERM...VALID FOR TDY AND WED...

MAIN FORECAST PROBLEM FOR THE SHORT TERM CONCERNS CONSIDERABLE
AREAS OF FOG ACROSS THE FORECAST AREA...PARTICULARLY IN THE
LOWER ELEVATIONS OF THE WESTERN ZONES. THE PATTERN FAVORS THIS TO
CONTINUE WITH A RIDGE ALOFT AND SURFACE LOW PRESSURE TO OUR
WEST/SOUTHWEST THIS IS KEEPING A SOUTHEAST LOW LEVEL FLOW
UPSLOPING INTO SOUTH CENTRAL MONTANA. LOCAL OBSERVATIONS SHOW A
QUARTER MILE VISIBILITY OR LESS IN AREAS JUST WEST OF BILLINGS TO
LIVINGSTON AND UP TO JUDITH GAP. MESOSCALE CROSS SECTIONS SHOW
THIS PERSISTING THROUGH MUCH OF THE MORNING FOR THIS AREA...AND
PERHAPS EVEN INTO THE AFTERNOON FOR PARK COUNTY AROUND LIVINGSTON.
THIS WILL ALSO TEND TO PREVENT MUCH IF ANY SOLAR RADIATION FOR
MUCH OF THE DAY AND SINCE MOS GUIDANCE IS NOT TAKING IT INTO
ACCOUNT I WILL BE SURE TO UNDERCUT GUIDANCE IN THESE AREAS. MAIN
MESSAGE...FOGGY AND CONTINUED CHILLY MOST LOCATIONS TODAY.

DENSE FOG ADVISORY...ISSUED ACROSS AREAS GENERALLY FROM LIVINGSTON
TO BIG TIMBER AND UP TO JUDITH GAP WHERE OBSERVATIONS INDICATE
PERSISTENT DENSE FOG. LOCALLY ICY ROADS WILL MAKE THIS EVEN MORE
DANGEROUS. AS MENTIONED BEFORE PROGGS SUGGEST THE WIDESPREAD FOG
WILL LINGER IN THESE AREAS UNTIL ABOUT 18Z.

IN THE MEANTIME...THE 500MB RIDGE BUILDING OVER US NOW WILL
QUICKLY BREAK DOWN LATE TODAY AND TONIGHT AS ANOTHER BROAD SPLIT
FLOW TROUGH MOVES INTO THE WESTERN UNITED STATES. A WEAKER SHORT
WAVE IN THE MEAN FLOW WILL SPLIT FROM THE SOUTHERN BRANCH AND
TRACK OVER OUR REGION TONIGHT AND INTO WEDNESDAY. QPF PROGGS ARE
NOT IMPRESSIVE BUT SEEMS PRUDENT TO BUMP UP SOME OF THE POPS NOW
FOR THE HIGH COUNTRY. WE MAY SEE SOME FLURRIES OR LIGHT SNOW IN
THE EAST AS IT MOVES THROUGH WEDNESDAY MORNING AS WELL. LOOK FOR A
MODEST WARM UP TO AROUND SEASONAL AVERAGES FOR WEDNESDAY. BT

.LONG TERM...VALID FOR THU...FRI...SAT...SUN...MON...

ENSEMBLE FORECASTS FROM THE GFS AND ECMWF WERE SHOWING MORE
CONFIDENCE IN THEIR SOLUTIONS FOR THE EXTENDED PERIOD THAN THEY
HAVE IN PREVIOUS RUNS.

FLOW GENERALLY BECOMES MORE PROGRESSIVE WITH TIME. WEAK NORTHERN
STREAM OF A PACIFIC TROUGH WILL BE OVER THE REGION ON THU. THIS
WILL BE FOLLOWED BY A SHORTWAVE RIDGE ON FRI AND ANOTHER WEAK
TROUGH FOR SAT. WENT WITH SUPER BLEND POPS FOR THIS PERIOD WHERE
MOISTURE AFFECTS MAINLY THE MOUNTAINS. A STRONG PACIFIC JET WILL
MOVE INTO THE REGION LATE IN THE PERIOD WHICH RESULTS IN A FAST
WNW FLOW OVERTAKING THE AREA BEGINNING ON SUN. ENERGY WILL MOVE
THROUGH THIS FLOW ALONG WITH PERIODS OF PACIFIC MOISTURE. GEFS
SHOWED AN ATMOSPHERIC RIVER WILL AFFECT THE REGION SUN INTO MON
WHICH WILL CONTRIBUTE TO PRECIPITATION CHANCES. HAVE INCREASED
POPS OVER THE AREA BEGINNING ON SUN. MAY HAVE GAP WIND ISSUES SAT
NIGHT INTO MON AS MODELS AGREED ON STRONG LEE TROUGHING OVER THE
AREA. WILL CONTINUE TO HAVE STRONG WINDS IN THE FORECAST FOR THE
GAP AREAS. THE MODELS WERE IN GOOD AGREEMENT WITH TEMPERATURES
THROUGH THE EXTENDED AND SHOWED ABOVE NORMAL READINGS. ARTHUR
&&

.AVIATION...

LIFR TO VLIFR CONDITIONS IN STRATUS AND FOG WILL PERSIST FROM
ROSEBUD COUNTY W THROUGH MOST OF THE DAY. LATEST SHORT RANGE
GUIDANCE SHOWS LITTLE IMPROVEMENT. TONIGHT CONDITIONS WILL LIKELY
DEGRADE FROM ANY IMPROVEMENTS TODAY. MOUNTAIN OBSCURATIONS WILL
BE WIDESPREAD THROUGH TONIGHT. REIMER

&&

.PRELIMINARY POINT TEMP/POPS...

    TDY WED     THU     FRI     SAT     SUN     MON
-------------------------------------------------------
BIL 027 020/036 022/039 023/039 026/042 025/043 035/045
    0/E 11/B    01/B    10/U    11/B    12/W    23/W
LVM 029 024/042 023/042 022/041 026/043 026/043 033/045
    1/E 22/J    11/E    11/U    11/B    13/W    33/W
HDN 029 014/033 015/037 017/038 019/040 019/041 028/043
    0/E 01/B    01/B    10/U    01/B    11/B    23/W
MLS 027 015/030 017/036 019/037 018/038 022/039 028/042
    0/E 01/B    01/B    10/U    01/U    11/U    23/W
4BQ 030 015/033 016/040 018/040 016/041 020/042 027/043
    0/E 02/J    01/B    10/U    01/U    11/B    23/W
BHK 024 012/028 015/035 019/037 016/038 020/039 025/041
    0/E 02/J    11/B    11/U    01/U    11/B    23/W
SHR 028 015/036 016/038 016/038 019/040 019/041 026/042
    0/E 01/B    01/B    10/U    01/B    12/J    33/W

&&

.BYZ WATCHES/WARNINGS/ADVISORIES...
MT...DENSE FOG ADVISORY IN EFFECT UNTIL 11 AM MST THIS MORNING FOR
      ZONES 28-34-41-63.
WY...NONE.

&&

$$
WEATHER.GOV/BILLINGS




000
FXUS65 KBYZ 161701
AFDBYZ

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BILLINGS MT
1001 AM MST TUE DEC 16 2014

.UPDATE...
AREAS OF FOG STILL LINGER OVER THE AREA THIS MORNING. WILL
CONTINUE TO KEEP FOG IN THE FORECAST THROUGH 19Z. IR SATELLITE
SHOWING MID LEVEL CLOUD DECK MOVING INTO OUR WESTERN ZONES AT 16Z
AND THIS HAS ALLOWED FOG AND LOW STRATUS DECK TO DISSIPATE IN
LIVINGSTON. WILL GO AHEAD AND DROP THE DENSE FOG ADVISORY FOR
KLVM. VISIBILITY STILL DOWN TO A 1/4 MILES FROM BIG TIMBER TO
EXPECT FOG TO SLOWLY DISSIPATE BY LATE MORNING OVER THESE AREAS
AS WELL AS IN THE BILLINGS AREA WITH MID LEVEL CLOUD DECK MOVING
IN. DID BACK OFF ON HIGH TEMPERATURES IN THE WEST A FEW DEGREES
WITH EXPECTED CLOUD COVER TODAY.

FOG MAY REDEVELOP OVER THE ENTIRE AREA TONIGHT AND WILL BE MAINLY
FROM HYSHAM WESTWARD. WILL ADDRESS THIS WITH THE AFTERNOON
FORECAST PACKAGE. RICHMOND

&&

.SHORT TERM...VALID FOR TDY AND WED...

MAIN FORECAST PROBLEM FOR THE SHORT TERM CONCERNS CONSIDERABLE
AREAS OF FOG ACROSS THE FORECAST AREA...PARTICULARLY IN THE
LOWER ELEVATIONS OF THE WESTERN ZONES. THE PATTERN FAVORS THIS TO
CONTINUE WITH A RIDGE ALOFT AND SURFACE LOW PRESSURE TO OUR
WEST/SOUTHWEST THIS IS KEEPING A SOUTHEAST LOW LEVEL FLOW
UPSLOPING INTO SOUTH CENTRAL MONTANA. LOCAL OBSERVATIONS SHOW A
QUARTER MILE VISIBILITY OR LESS IN AREAS JUST WEST OF BILLINGS TO
LIVINGSTON AND UP TO JUDITH GAP. MESOSCALE CROSS SECTIONS SHOW
THIS PERSISTING THROUGH MUCH OF THE MORNING FOR THIS AREA...AND
PERHAPS EVEN INTO THE AFTERNOON FOR PARK COUNTY AROUND LIVINGSTON.
THIS WILL ALSO TEND TO PREVENT MUCH IF ANY SOLAR RADIATION FOR
MUCH OF THE DAY AND SINCE MOS GUIDANCE IS NOT TAKING IT INTO
ACCOUNT I WILL BE SURE TO UNDERCUT GUIDANCE IN THESE AREAS. MAIN
MESSAGE...FOGGY AND CONTINUED CHILLY MOST LOCATIONS TODAY.

DENSE FOG ADVISORY...ISSUED ACROSS AREAS GENERALLY FROM LIVINGSTON
TO BIG TIMBER AND UP TO JUDITH GAP WHERE OBSERVATIONS INDICATE
PERSISTENT DENSE FOG. LOCALLY ICY ROADS WILL MAKE THIS EVEN MORE
DANGEROUS. AS MENTIONED BEFORE PROGGS SUGGEST THE WIDESPREAD FOG
WILL LINGER IN THESE AREAS UNTIL ABOUT 18Z.

IN THE MEANTIME...THE 500MB RIDGE BUILDING OVER US NOW WILL
QUICKLY BREAK DOWN LATE TODAY AND TONIGHT AS ANOTHER BROAD SPLIT
FLOW TROUGH MOVES INTO THE WESTERN UNITED STATES. A WEAKER SHORT
WAVE IN THE MEAN FLOW WILL SPLIT FROM THE SOUTHERN BRANCH AND
TRACK OVER OUR REGION TONIGHT AND INTO WEDNESDAY. QPF PROGGS ARE
NOT IMPRESSIVE BUT SEEMS PRUDENT TO BUMP UP SOME OF THE POPS NOW
FOR THE HIGH COUNTRY. WE MAY SEE SOME FLURRIES OR LIGHT SNOW IN
THE EAST AS IT MOVES THROUGH WEDNESDAY MORNING AS WELL. LOOK FOR A
MODEST WARM UP TO AROUND SEASONAL AVERAGES FOR WEDNESDAY. BT

.LONG TERM...VALID FOR THU...FRI...SAT...SUN...MON...

ENSEMBLE FORECASTS FROM THE GFS AND ECMWF WERE SHOWING MORE
CONFIDENCE IN THEIR SOLUTIONS FOR THE EXTENDED PERIOD THAN THEY
HAVE IN PREVIOUS RUNS.

FLOW GENERALLY BECOMES MORE PROGRESSIVE WITH TIME. WEAK NORTHERN
STREAM OF A PACIFIC TROUGH WILL BE OVER THE REGION ON THU. THIS
WILL BE FOLLOWED BY A SHORTWAVE RIDGE ON FRI AND ANOTHER WEAK
TROUGH FOR SAT. WENT WITH SUPER BLEND POPS FOR THIS PERIOD WHERE
MOISTURE AFFECTS MAINLY THE MOUNTAINS. A STRONG PACIFIC JET WILL
MOVE INTO THE REGION LATE IN THE PERIOD WHICH RESULTS IN A FAST
WNW FLOW OVERTAKING THE AREA BEGINNING ON SUN. ENERGY WILL MOVE
THROUGH THIS FLOW ALONG WITH PERIODS OF PACIFIC MOISTURE. GEFS
SHOWED AN ATMOSPHERIC RIVER WILL AFFECT THE REGION SUN INTO MON
WHICH WILL CONTRIBUTE TO PRECIPITATION CHANCES. HAVE INCREASED
POPS OVER THE AREA BEGINNING ON SUN. MAY HAVE GAP WIND ISSUES SAT
NIGHT INTO MON AS MODELS AGREED ON STRONG LEE TROUGHING OVER THE
AREA. WILL CONTINUE TO HAVE STRONG WINDS IN THE FORECAST FOR THE
GAP AREAS. THE MODELS WERE IN GOOD AGREEMENT WITH TEMPERATURES
THROUGH THE EXTENDED AND SHOWED ABOVE NORMAL READINGS. ARTHUR
&&

.AVIATION...

LIFR TO VLIFR CONDITIONS IN STRATUS AND FOG WILL PERSIST FROM
ROSEBUD COUNTY W THROUGH MOST OF THE DAY. LATEST SHORT RANGE
GUIDANCE SHOWS LITTLE IMPROVEMENT. TONIGHT CONDITIONS WILL LIKELY
DEGRADE FROM ANY IMPROVEMENTS TODAY. MOUNTAIN OBSCURATIONS WILL
BE WIDESPREAD THROUGH TONIGHT. REIMER

&&

.PRELIMINARY POINT TEMP/POPS...

    TDY WED     THU     FRI     SAT     SUN     MON
-------------------------------------------------------
BIL 027 020/036 022/039 023/039 026/042 025/043 035/045
    0/E 11/B    01/B    10/U    11/B    12/W    23/W
LVM 029 024/042 023/042 022/041 026/043 026/043 033/045
    1/E 22/J    11/E    11/U    11/B    13/W    33/W
HDN 029 014/033 015/037 017/038 019/040 019/041 028/043
    0/E 01/B    01/B    10/U    01/B    11/B    23/W
MLS 027 015/030 017/036 019/037 018/038 022/039 028/042
    0/E 01/B    01/B    10/U    01/U    11/U    23/W
4BQ 030 015/033 016/040 018/040 016/041 020/042 027/043
    0/E 02/J    01/B    10/U    01/U    11/B    23/W
BHK 024 012/028 015/035 019/037 016/038 020/039 025/041
    0/E 02/J    11/B    11/U    01/U    11/B    23/W
SHR 028 015/036 016/038 016/038 019/040 019/041 026/042
    0/E 01/B    01/B    10/U    01/B    12/J    33/W

&&

.BYZ WATCHES/WARNINGS/ADVISORIES...
MT...DENSE FOG ADVISORY IN EFFECT UNTIL 11 AM MST THIS MORNING FOR
      ZONES 28-34-41-63.
WY...NONE.

&&

$$
WEATHER.GOV/BILLINGS




000
FXUS65 KBYZ 161701
AFDBYZ

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BILLINGS MT
1001 AM MST TUE DEC 16 2014

.UPDATE...
AREAS OF FOG STILL LINGER OVER THE AREA THIS MORNING. WILL
CONTINUE TO KEEP FOG IN THE FORECAST THROUGH 19Z. IR SATELLITE
SHOWING MID LEVEL CLOUD DECK MOVING INTO OUR WESTERN ZONES AT 16Z
AND THIS HAS ALLOWED FOG AND LOW STRATUS DECK TO DISSIPATE IN
LIVINGSTON. WILL GO AHEAD AND DROP THE DENSE FOG ADVISORY FOR
KLVM. VISIBILITY STILL DOWN TO A 1/4 MILES FROM BIG TIMBER TO
EXPECT FOG TO SLOWLY DISSIPATE BY LATE MORNING OVER THESE AREAS
AS WELL AS IN THE BILLINGS AREA WITH MID LEVEL CLOUD DECK MOVING
IN. DID BACK OFF ON HIGH TEMPERATURES IN THE WEST A FEW DEGREES
WITH EXPECTED CLOUD COVER TODAY.

FOG MAY REDEVELOP OVER THE ENTIRE AREA TONIGHT AND WILL BE MAINLY
FROM HYSHAM WESTWARD. WILL ADDRESS THIS WITH THE AFTERNOON
FORECAST PACKAGE. RICHMOND

&&

.SHORT TERM...VALID FOR TDY AND WED...

MAIN FORECAST PROBLEM FOR THE SHORT TERM CONCERNS CONSIDERABLE
AREAS OF FOG ACROSS THE FORECAST AREA...PARTICULARLY IN THE
LOWER ELEVATIONS OF THE WESTERN ZONES. THE PATTERN FAVORS THIS TO
CONTINUE WITH A RIDGE ALOFT AND SURFACE LOW PRESSURE TO OUR
WEST/SOUTHWEST THIS IS KEEPING A SOUTHEAST LOW LEVEL FLOW
UPSLOPING INTO SOUTH CENTRAL MONTANA. LOCAL OBSERVATIONS SHOW A
QUARTER MILE VISIBILITY OR LESS IN AREAS JUST WEST OF BILLINGS TO
LIVINGSTON AND UP TO JUDITH GAP. MESOSCALE CROSS SECTIONS SHOW
THIS PERSISTING THROUGH MUCH OF THE MORNING FOR THIS AREA...AND
PERHAPS EVEN INTO THE AFTERNOON FOR PARK COUNTY AROUND LIVINGSTON.
THIS WILL ALSO TEND TO PREVENT MUCH IF ANY SOLAR RADIATION FOR
MUCH OF THE DAY AND SINCE MOS GUIDANCE IS NOT TAKING IT INTO
ACCOUNT I WILL BE SURE TO UNDERCUT GUIDANCE IN THESE AREAS. MAIN
MESSAGE...FOGGY AND CONTINUED CHILLY MOST LOCATIONS TODAY.

DENSE FOG ADVISORY...ISSUED ACROSS AREAS GENERALLY FROM LIVINGSTON
TO BIG TIMBER AND UP TO JUDITH GAP WHERE OBSERVATIONS INDICATE
PERSISTENT DENSE FOG. LOCALLY ICY ROADS WILL MAKE THIS EVEN MORE
DANGEROUS. AS MENTIONED BEFORE PROGGS SUGGEST THE WIDESPREAD FOG
WILL LINGER IN THESE AREAS UNTIL ABOUT 18Z.

IN THE MEANTIME...THE 500MB RIDGE BUILDING OVER US NOW WILL
QUICKLY BREAK DOWN LATE TODAY AND TONIGHT AS ANOTHER BROAD SPLIT
FLOW TROUGH MOVES INTO THE WESTERN UNITED STATES. A WEAKER SHORT
WAVE IN THE MEAN FLOW WILL SPLIT FROM THE SOUTHERN BRANCH AND
TRACK OVER OUR REGION TONIGHT AND INTO WEDNESDAY. QPF PROGGS ARE
NOT IMPRESSIVE BUT SEEMS PRUDENT TO BUMP UP SOME OF THE POPS NOW
FOR THE HIGH COUNTRY. WE MAY SEE SOME FLURRIES OR LIGHT SNOW IN
THE EAST AS IT MOVES THROUGH WEDNESDAY MORNING AS WELL. LOOK FOR A
MODEST WARM UP TO AROUND SEASONAL AVERAGES FOR WEDNESDAY. BT

.LONG TERM...VALID FOR THU...FRI...SAT...SUN...MON...

ENSEMBLE FORECASTS FROM THE GFS AND ECMWF WERE SHOWING MORE
CONFIDENCE IN THEIR SOLUTIONS FOR THE EXTENDED PERIOD THAN THEY
HAVE IN PREVIOUS RUNS.

FLOW GENERALLY BECOMES MORE PROGRESSIVE WITH TIME. WEAK NORTHERN
STREAM OF A PACIFIC TROUGH WILL BE OVER THE REGION ON THU. THIS
WILL BE FOLLOWED BY A SHORTWAVE RIDGE ON FRI AND ANOTHER WEAK
TROUGH FOR SAT. WENT WITH SUPER BLEND POPS FOR THIS PERIOD WHERE
MOISTURE AFFECTS MAINLY THE MOUNTAINS. A STRONG PACIFIC JET WILL
MOVE INTO THE REGION LATE IN THE PERIOD WHICH RESULTS IN A FAST
WNW FLOW OVERTAKING THE AREA BEGINNING ON SUN. ENERGY WILL MOVE
THROUGH THIS FLOW ALONG WITH PERIODS OF PACIFIC MOISTURE. GEFS
SHOWED AN ATMOSPHERIC RIVER WILL AFFECT THE REGION SUN INTO MON
WHICH WILL CONTRIBUTE TO PRECIPITATION CHANCES. HAVE INCREASED
POPS OVER THE AREA BEGINNING ON SUN. MAY HAVE GAP WIND ISSUES SAT
NIGHT INTO MON AS MODELS AGREED ON STRONG LEE TROUGHING OVER THE
AREA. WILL CONTINUE TO HAVE STRONG WINDS IN THE FORECAST FOR THE
GAP AREAS. THE MODELS WERE IN GOOD AGREEMENT WITH TEMPERATURES
THROUGH THE EXTENDED AND SHOWED ABOVE NORMAL READINGS. ARTHUR
&&

.AVIATION...

LIFR TO VLIFR CONDITIONS IN STRATUS AND FOG WILL PERSIST FROM
ROSEBUD COUNTY W THROUGH MOST OF THE DAY. LATEST SHORT RANGE
GUIDANCE SHOWS LITTLE IMPROVEMENT. TONIGHT CONDITIONS WILL LIKELY
DEGRADE FROM ANY IMPROVEMENTS TODAY. MOUNTAIN OBSCURATIONS WILL
BE WIDESPREAD THROUGH TONIGHT. REIMER

&&

.PRELIMINARY POINT TEMP/POPS...

    TDY WED     THU     FRI     SAT     SUN     MON
-------------------------------------------------------
BIL 027 020/036 022/039 023/039 026/042 025/043 035/045
    0/E 11/B    01/B    10/U    11/B    12/W    23/W
LVM 029 024/042 023/042 022/041 026/043 026/043 033/045
    1/E 22/J    11/E    11/U    11/B    13/W    33/W
HDN 029 014/033 015/037 017/038 019/040 019/041 028/043
    0/E 01/B    01/B    10/U    01/B    11/B    23/W
MLS 027 015/030 017/036 019/037 018/038 022/039 028/042
    0/E 01/B    01/B    10/U    01/U    11/U    23/W
4BQ 030 015/033 016/040 018/040 016/041 020/042 027/043
    0/E 02/J    01/B    10/U    01/U    11/B    23/W
BHK 024 012/028 015/035 019/037 016/038 020/039 025/041
    0/E 02/J    11/B    11/U    01/U    11/B    23/W
SHR 028 015/036 016/038 016/038 019/040 019/041 026/042
    0/E 01/B    01/B    10/U    01/B    12/J    33/W

&&

.BYZ WATCHES/WARNINGS/ADVISORIES...
MT...DENSE FOG ADVISORY IN EFFECT UNTIL 11 AM MST THIS MORNING FOR
      ZONES 28-34-41-63.
WY...NONE.

&&

$$
WEATHER.GOV/BILLINGS




000
FXUS65 KBYZ 161701
AFDBYZ

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BILLINGS MT
1001 AM MST TUE DEC 16 2014

.UPDATE...
AREAS OF FOG STILL LINGER OVER THE AREA THIS MORNING. WILL
CONTINUE TO KEEP FOG IN THE FORECAST THROUGH 19Z. IR SATELLITE
SHOWING MID LEVEL CLOUD DECK MOVING INTO OUR WESTERN ZONES AT 16Z
AND THIS HAS ALLOWED FOG AND LOW STRATUS DECK TO DISSIPATE IN
LIVINGSTON. WILL GO AHEAD AND DROP THE DENSE FOG ADVISORY FOR
KLVM. VISIBILITY STILL DOWN TO A 1/4 MILES FROM BIG TIMBER TO
EXPECT FOG TO SLOWLY DISSIPATE BY LATE MORNING OVER THESE AREAS
AS WELL AS IN THE BILLINGS AREA WITH MID LEVEL CLOUD DECK MOVING
IN. DID BACK OFF ON HIGH TEMPERATURES IN THE WEST A FEW DEGREES
WITH EXPECTED CLOUD COVER TODAY.

FOG MAY REDEVELOP OVER THE ENTIRE AREA TONIGHT AND WILL BE MAINLY
FROM HYSHAM WESTWARD. WILL ADDRESS THIS WITH THE AFTERNOON
FORECAST PACKAGE. RICHMOND

&&

.SHORT TERM...VALID FOR TDY AND WED...

MAIN FORECAST PROBLEM FOR THE SHORT TERM CONCERNS CONSIDERABLE
AREAS OF FOG ACROSS THE FORECAST AREA...PARTICULARLY IN THE
LOWER ELEVATIONS OF THE WESTERN ZONES. THE PATTERN FAVORS THIS TO
CONTINUE WITH A RIDGE ALOFT AND SURFACE LOW PRESSURE TO OUR
WEST/SOUTHWEST THIS IS KEEPING A SOUTHEAST LOW LEVEL FLOW
UPSLOPING INTO SOUTH CENTRAL MONTANA. LOCAL OBSERVATIONS SHOW A
QUARTER MILE VISIBILITY OR LESS IN AREAS JUST WEST OF BILLINGS TO
LIVINGSTON AND UP TO JUDITH GAP. MESOSCALE CROSS SECTIONS SHOW
THIS PERSISTING THROUGH MUCH OF THE MORNING FOR THIS AREA...AND
PERHAPS EVEN INTO THE AFTERNOON FOR PARK COUNTY AROUND LIVINGSTON.
THIS WILL ALSO TEND TO PREVENT MUCH IF ANY SOLAR RADIATION FOR
MUCH OF THE DAY AND SINCE MOS GUIDANCE IS NOT TAKING IT INTO
ACCOUNT I WILL BE SURE TO UNDERCUT GUIDANCE IN THESE AREAS. MAIN
MESSAGE...FOGGY AND CONTINUED CHILLY MOST LOCATIONS TODAY.

DENSE FOG ADVISORY...ISSUED ACROSS AREAS GENERALLY FROM LIVINGSTON
TO BIG TIMBER AND UP TO JUDITH GAP WHERE OBSERVATIONS INDICATE
PERSISTENT DENSE FOG. LOCALLY ICY ROADS WILL MAKE THIS EVEN MORE
DANGEROUS. AS MENTIONED BEFORE PROGGS SUGGEST THE WIDESPREAD FOG
WILL LINGER IN THESE AREAS UNTIL ABOUT 18Z.

IN THE MEANTIME...THE 500MB RIDGE BUILDING OVER US NOW WILL
QUICKLY BREAK DOWN LATE TODAY AND TONIGHT AS ANOTHER BROAD SPLIT
FLOW TROUGH MOVES INTO THE WESTERN UNITED STATES. A WEAKER SHORT
WAVE IN THE MEAN FLOW WILL SPLIT FROM THE SOUTHERN BRANCH AND
TRACK OVER OUR REGION TONIGHT AND INTO WEDNESDAY. QPF PROGGS ARE
NOT IMPRESSIVE BUT SEEMS PRUDENT TO BUMP UP SOME OF THE POPS NOW
FOR THE HIGH COUNTRY. WE MAY SEE SOME FLURRIES OR LIGHT SNOW IN
THE EAST AS IT MOVES THROUGH WEDNESDAY MORNING AS WELL. LOOK FOR A
MODEST WARM UP TO AROUND SEASONAL AVERAGES FOR WEDNESDAY. BT

.LONG TERM...VALID FOR THU...FRI...SAT...SUN...MON...

ENSEMBLE FORECASTS FROM THE GFS AND ECMWF WERE SHOWING MORE
CONFIDENCE IN THEIR SOLUTIONS FOR THE EXTENDED PERIOD THAN THEY
HAVE IN PREVIOUS RUNS.

FLOW GENERALLY BECOMES MORE PROGRESSIVE WITH TIME. WEAK NORTHERN
STREAM OF A PACIFIC TROUGH WILL BE OVER THE REGION ON THU. THIS
WILL BE FOLLOWED BY A SHORTWAVE RIDGE ON FRI AND ANOTHER WEAK
TROUGH FOR SAT. WENT WITH SUPER BLEND POPS FOR THIS PERIOD WHERE
MOISTURE AFFECTS MAINLY THE MOUNTAINS. A STRONG PACIFIC JET WILL
MOVE INTO THE REGION LATE IN THE PERIOD WHICH RESULTS IN A FAST
WNW FLOW OVERTAKING THE AREA BEGINNING ON SUN. ENERGY WILL MOVE
THROUGH THIS FLOW ALONG WITH PERIODS OF PACIFIC MOISTURE. GEFS
SHOWED AN ATMOSPHERIC RIVER WILL AFFECT THE REGION SUN INTO MON
WHICH WILL CONTRIBUTE TO PRECIPITATION CHANCES. HAVE INCREASED
POPS OVER THE AREA BEGINNING ON SUN. MAY HAVE GAP WIND ISSUES SAT
NIGHT INTO MON AS MODELS AGREED ON STRONG LEE TROUGHING OVER THE
AREA. WILL CONTINUE TO HAVE STRONG WINDS IN THE FORECAST FOR THE
GAP AREAS. THE MODELS WERE IN GOOD AGREEMENT WITH TEMPERATURES
THROUGH THE EXTENDED AND SHOWED ABOVE NORMAL READINGS. ARTHUR
&&

.AVIATION...

LIFR TO VLIFR CONDITIONS IN STRATUS AND FOG WILL PERSIST FROM
ROSEBUD COUNTY W THROUGH MOST OF THE DAY. LATEST SHORT RANGE
GUIDANCE SHOWS LITTLE IMPROVEMENT. TONIGHT CONDITIONS WILL LIKELY
DEGRADE FROM ANY IMPROVEMENTS TODAY. MOUNTAIN OBSCURATIONS WILL
BE WIDESPREAD THROUGH TONIGHT. REIMER

&&

.PRELIMINARY POINT TEMP/POPS...

    TDY WED     THU     FRI     SAT     SUN     MON
-------------------------------------------------------
BIL 027 020/036 022/039 023/039 026/042 025/043 035/045
    0/E 11/B    01/B    10/U    11/B    12/W    23/W
LVM 029 024/042 023/042 022/041 026/043 026/043 033/045
    1/E 22/J    11/E    11/U    11/B    13/W    33/W
HDN 029 014/033 015/037 017/038 019/040 019/041 028/043
    0/E 01/B    01/B    10/U    01/B    11/B    23/W
MLS 027 015/030 017/036 019/037 018/038 022/039 028/042
    0/E 01/B    01/B    10/U    01/U    11/U    23/W
4BQ 030 015/033 016/040 018/040 016/041 020/042 027/043
    0/E 02/J    01/B    10/U    01/U    11/B    23/W
BHK 024 012/028 015/035 019/037 016/038 020/039 025/041
    0/E 02/J    11/B    11/U    01/U    11/B    23/W
SHR 028 015/036 016/038 016/038 019/040 019/041 026/042
    0/E 01/B    01/B    10/U    01/B    12/J    33/W

&&

.BYZ WATCHES/WARNINGS/ADVISORIES...
MT...DENSE FOG ADVISORY IN EFFECT UNTIL 11 AM MST THIS MORNING FOR
      ZONES 28-34-41-63.
WY...NONE.

&&

$$
WEATHER.GOV/BILLINGS




000
FXUS65 KGGW 161636
AFDGGW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GLASGOW MT
936 AM MST TUE DEC 16 2014

.SHORT TERM...FOR NORTHEAST MONTANA...TODAY THROUGH THURSDAY...
NO CHANGES.

NOT A LOT OF CONFIDENCE WITH CURRENT LOW STRATUS CLOUD DECK THAT IS
COVERING A WIDE AREA ACROSS THE REGION. MOST MODELS ARE SHOWING
THAT THERE SHOULD BE LESS COVERAGE...SO HAVE TO USE OTHER TOOLS TO
GET A HANDLE ON IT. FORECASTED SOUNDINGS SHOW THAT INVERSION SHOULD
WORK DOWN AND THAT STRATUS MAY THIN THIS AFTERNOON.

FOR TONIGHT...WINDS LOOK TOO STRONG FOR FOG FORMATION BUT WILL
CONTINUE TO LOOK AT THIS POSSIBILITY. MAYBE IT WILL BE AN ELEVATED
ADVECTION FOG ISSUE. TFJ

PREVIOUS DISCUSSION...
SHALLOW STRATUS DECK REMAINS IN PLACE OVER EASTERN MONTANA THIS
MORNING. MOISTURE MOSTLY BELOW 850MB AS EVIDENCE BY 0Z GGW
SOUNDING AND SATELLITE SHOWING THE LITTLE ROCKIES AND BEARS PAWS
STICKING OUT OF THE CLOUD. MAIN FORECAST ISSUE WILL BE HOW LONG
DOES THE LOW CLOUD PERSIST. GIVEN THE INVERSION AND DRY AIR ALOFT
LITTLE MIXING IS EXPECTED BUT COULD SEE SOME SHALLOWING FOR MORE
OF THE HIGHER TERRAIN AREAS GETTING INTO THE CLOUD LAYER FOR FOG
OR GETTING ABOVE IT FOR CLEARING. SHORTWAVE MOVING TOWARD THE
REGION TONIGHT COULD RESULT IN ENOUGH TURBULENCE TO MIX OUT THE
LOW LEVEL MOISTURE.

SHORTWAVE DOES BRING TO ELEVATED MOISTURE AND LIFT ALONG A FRONTAL
BOUNDARY ON WEDNESDAY FOR A FEW SNOW SHOWERS. WESTERLY FLOW BEHIND
THE WAVE SHOULD RESULT IN SLIGHTLY WARMER TEMPERATURES IN THE
SOUTHWEST ZONES. EBERT


.LONG TERM...THURSDAY NIGHT THROUGH TUESDAY...

SYNOPTIC SET UP... WITH WEAK POOLED COLD AIR AT THE SURFACE OVER
THE EASTERN GREAT PLAINS. A RIDGE RUNS UP THE COAST FROM
CALIFORNIA TO SOUTHERN BRITISH COLUMBIA. NORTHEAST MONTANA LIES
BETWEEN THESE TWO FEATURES IN A UNENERGETIC WEAK NORTHWESTERN FLOW.
COLDEST AIR OF THE NORTHERN HEMISPHERE LIES BOTTLED UP OVER THE
ARCTIC.

THURSDAY NIGHT THROUGH SUNDAY... RIDGE TO THE WEST GAINS
INCREASING INFLUENCE AND PLACES NORTHEAST MONTANA UNDER PARTLY
CLOUDY AND DRY CONDITIONS DUE TO A STABLE ATMOSPHERE. SUBTLE
SHORTWAVES APPEAR IN THE FLOW... ESPECIALLY ON SATURDAY... BUT
REMAIN RELATIVELY UN-ENERGIZED AND SEEM INSUFFICIENT TO CAUSE
PRECIPITATION AT THIS TIME.

SUNDAY NIGHT ONWARD... WESTERN RIDGE WILL FINALLY MOVE THROUGH
THE AREA AND GENERATE CONDITIONS FOR A PREFRONTAL WARMING SPIKE
ON SUNDAY NIGHT. BY MONDAY AN ARCTIC INTRUSION IS ANTICIPATED TO
BEGIN AND WILL BRING A COLD FRONT THROUGH THE REGION. POSSIBLE
PACIFIC MOISTURE AT THE CREST OF THE EXITING RIDGE COULD HELP TO
GENERATE SHOWER STARTING DURING THIS PERIOD AND LASTING THROUGH
TUESDAY. AFTERWARD TEMPERATURES ARE EXPECTED TO BEGIN DROPPING
OFF.

GAH

&&

.AVIATION...
MVFR STRATUS WILL CONTINUE OVER THE TAF SITES FOR THE REST OF THIS
MORNING. A FEW BREAKS MAY OCCUR THIS AFTERNOON BUT CONFIDENCE IS
LOW. SOUTHEAST WINDS WILL HOVER AROUND 10 KTS. MALIAWCO


&&

.GLASGOW WATCHES/WARNINGS/ADVISORIES...NONE.

&&

$$

WEATHER.GOV/GLASGOW






000
FXUS65 KGGW 161636
AFDGGW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GLASGOW MT
936 AM MST TUE DEC 16 2014

.SHORT TERM...FOR NORTHEAST MONTANA...TODAY THROUGH THURSDAY...
NO CHANGES.

NOT A LOT OF CONFIDENCE WITH CURRENT LOW STRATUS CLOUD DECK THAT IS
COVERING A WIDE AREA ACROSS THE REGION. MOST MODELS ARE SHOWING
THAT THERE SHOULD BE LESS COVERAGE...SO HAVE TO USE OTHER TOOLS TO
GET A HANDLE ON IT. FORECASTED SOUNDINGS SHOW THAT INVERSION SHOULD
WORK DOWN AND THAT STRATUS MAY THIN THIS AFTERNOON.

FOR TONIGHT...WINDS LOOK TOO STRONG FOR FOG FORMATION BUT WILL
CONTINUE TO LOOK AT THIS POSSIBILITY. MAYBE IT WILL BE AN ELEVATED
ADVECTION FOG ISSUE. TFJ

PREVIOUS DISCUSSION...
SHALLOW STRATUS DECK REMAINS IN PLACE OVER EASTERN MONTANA THIS
MORNING. MOISTURE MOSTLY BELOW 850MB AS EVIDENCE BY 0Z GGW
SOUNDING AND SATELLITE SHOWING THE LITTLE ROCKIES AND BEARS PAWS
STICKING OUT OF THE CLOUD. MAIN FORECAST ISSUE WILL BE HOW LONG
DOES THE LOW CLOUD PERSIST. GIVEN THE INVERSION AND DRY AIR ALOFT
LITTLE MIXING IS EXPECTED BUT COULD SEE SOME SHALLOWING FOR MORE
OF THE HIGHER TERRAIN AREAS GETTING INTO THE CLOUD LAYER FOR FOG
OR GETTING ABOVE IT FOR CLEARING. SHORTWAVE MOVING TOWARD THE
REGION TONIGHT COULD RESULT IN ENOUGH TURBULENCE TO MIX OUT THE
LOW LEVEL MOISTURE.

SHORTWAVE DOES BRING TO ELEVATED MOISTURE AND LIFT ALONG A FRONTAL
BOUNDARY ON WEDNESDAY FOR A FEW SNOW SHOWERS. WESTERLY FLOW BEHIND
THE WAVE SHOULD RESULT IN SLIGHTLY WARMER TEMPERATURES IN THE
SOUTHWEST ZONES. EBERT


.LONG TERM...THURSDAY NIGHT THROUGH TUESDAY...

SYNOPTIC SET UP... WITH WEAK POOLED COLD AIR AT THE SURFACE OVER
THE EASTERN GREAT PLAINS. A RIDGE RUNS UP THE COAST FROM
CALIFORNIA TO SOUTHERN BRITISH COLUMBIA. NORTHEAST MONTANA LIES
BETWEEN THESE TWO FEATURES IN A UNENERGETIC WEAK NORTHWESTERN FLOW.
COLDEST AIR OF THE NORTHERN HEMISPHERE LIES BOTTLED UP OVER THE
ARCTIC.

THURSDAY NIGHT THROUGH SUNDAY... RIDGE TO THE WEST GAINS
INCREASING INFLUENCE AND PLACES NORTHEAST MONTANA UNDER PARTLY
CLOUDY AND DRY CONDITIONS DUE TO A STABLE ATMOSPHERE. SUBTLE
SHORTWAVES APPEAR IN THE FLOW... ESPECIALLY ON SATURDAY... BUT
REMAIN RELATIVELY UN-ENERGIZED AND SEEM INSUFFICIENT TO CAUSE
PRECIPITATION AT THIS TIME.

SUNDAY NIGHT ONWARD... WESTERN RIDGE WILL FINALLY MOVE THROUGH
THE AREA AND GENERATE CONDITIONS FOR A PREFRONTAL WARMING SPIKE
ON SUNDAY NIGHT. BY MONDAY AN ARCTIC INTRUSION IS ANTICIPATED TO
BEGIN AND WILL BRING A COLD FRONT THROUGH THE REGION. POSSIBLE
PACIFIC MOISTURE AT THE CREST OF THE EXITING RIDGE COULD HELP TO
GENERATE SHOWER STARTING DURING THIS PERIOD AND LASTING THROUGH
TUESDAY. AFTERWARD TEMPERATURES ARE EXPECTED TO BEGIN DROPPING
OFF.

GAH

&&

.AVIATION...
MVFR STRATUS WILL CONTINUE OVER THE TAF SITES FOR THE REST OF THIS
MORNING. A FEW BREAKS MAY OCCUR THIS AFTERNOON BUT CONFIDENCE IS
LOW. SOUTHEAST WINDS WILL HOVER AROUND 10 KTS. MALIAWCO


&&

.GLASGOW WATCHES/WARNINGS/ADVISORIES...NONE.

&&

$$

WEATHER.GOV/GLASGOW






000
FXUS65 KGGW 161636
AFDGGW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GLASGOW MT
936 AM MST TUE DEC 16 2014

.SHORT TERM...FOR NORTHEAST MONTANA...TODAY THROUGH THURSDAY...
NO CHANGES.

NOT A LOT OF CONFIDENCE WITH CURRENT LOW STRATUS CLOUD DECK THAT IS
COVERING A WIDE AREA ACROSS THE REGION. MOST MODELS ARE SHOWING
THAT THERE SHOULD BE LESS COVERAGE...SO HAVE TO USE OTHER TOOLS TO
GET A HANDLE ON IT. FORECASTED SOUNDINGS SHOW THAT INVERSION SHOULD
WORK DOWN AND THAT STRATUS MAY THIN THIS AFTERNOON.

FOR TONIGHT...WINDS LOOK TOO STRONG FOR FOG FORMATION BUT WILL
CONTINUE TO LOOK AT THIS POSSIBILITY. MAYBE IT WILL BE AN ELEVATED
ADVECTION FOG ISSUE. TFJ

PREVIOUS DISCUSSION...
SHALLOW STRATUS DECK REMAINS IN PLACE OVER EASTERN MONTANA THIS
MORNING. MOISTURE MOSTLY BELOW 850MB AS EVIDENCE BY 0Z GGW
SOUNDING AND SATELLITE SHOWING THE LITTLE ROCKIES AND BEARS PAWS
STICKING OUT OF THE CLOUD. MAIN FORECAST ISSUE WILL BE HOW LONG
DOES THE LOW CLOUD PERSIST. GIVEN THE INVERSION AND DRY AIR ALOFT
LITTLE MIXING IS EXPECTED BUT COULD SEE SOME SHALLOWING FOR MORE
OF THE HIGHER TERRAIN AREAS GETTING INTO THE CLOUD LAYER FOR FOG
OR GETTING ABOVE IT FOR CLEARING. SHORTWAVE MOVING TOWARD THE
REGION TONIGHT COULD RESULT IN ENOUGH TURBULENCE TO MIX OUT THE
LOW LEVEL MOISTURE.

SHORTWAVE DOES BRING TO ELEVATED MOISTURE AND LIFT ALONG A FRONTAL
BOUNDARY ON WEDNESDAY FOR A FEW SNOW SHOWERS. WESTERLY FLOW BEHIND
THE WAVE SHOULD RESULT IN SLIGHTLY WARMER TEMPERATURES IN THE
SOUTHWEST ZONES. EBERT


.LONG TERM...THURSDAY NIGHT THROUGH TUESDAY...

SYNOPTIC SET UP... WITH WEAK POOLED COLD AIR AT THE SURFACE OVER
THE EASTERN GREAT PLAINS. A RIDGE RUNS UP THE COAST FROM
CALIFORNIA TO SOUTHERN BRITISH COLUMBIA. NORTHEAST MONTANA LIES
BETWEEN THESE TWO FEATURES IN A UNENERGETIC WEAK NORTHWESTERN FLOW.
COLDEST AIR OF THE NORTHERN HEMISPHERE LIES BOTTLED UP OVER THE
ARCTIC.

THURSDAY NIGHT THROUGH SUNDAY... RIDGE TO THE WEST GAINS
INCREASING INFLUENCE AND PLACES NORTHEAST MONTANA UNDER PARTLY
CLOUDY AND DRY CONDITIONS DUE TO A STABLE ATMOSPHERE. SUBTLE
SHORTWAVES APPEAR IN THE FLOW... ESPECIALLY ON SATURDAY... BUT
REMAIN RELATIVELY UN-ENERGIZED AND SEEM INSUFFICIENT TO CAUSE
PRECIPITATION AT THIS TIME.

SUNDAY NIGHT ONWARD... WESTERN RIDGE WILL FINALLY MOVE THROUGH
THE AREA AND GENERATE CONDITIONS FOR A PREFRONTAL WARMING SPIKE
ON SUNDAY NIGHT. BY MONDAY AN ARCTIC INTRUSION IS ANTICIPATED TO
BEGIN AND WILL BRING A COLD FRONT THROUGH THE REGION. POSSIBLE
PACIFIC MOISTURE AT THE CREST OF THE EXITING RIDGE COULD HELP TO
GENERATE SHOWER STARTING DURING THIS PERIOD AND LASTING THROUGH
TUESDAY. AFTERWARD TEMPERATURES ARE EXPECTED TO BEGIN DROPPING
OFF.

GAH

&&

.AVIATION...
MVFR STRATUS WILL CONTINUE OVER THE TAF SITES FOR THE REST OF THIS
MORNING. A FEW BREAKS MAY OCCUR THIS AFTERNOON BUT CONFIDENCE IS
LOW. SOUTHEAST WINDS WILL HOVER AROUND 10 KTS. MALIAWCO


&&

.GLASGOW WATCHES/WARNINGS/ADVISORIES...NONE.

&&

$$

WEATHER.GOV/GLASGOW






000
FXUS65 KGGW 161636
AFDGGW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GLASGOW MT
936 AM MST TUE DEC 16 2014

.SHORT TERM...FOR NORTHEAST MONTANA...TODAY THROUGH THURSDAY...
NO CHANGES.

NOT A LOT OF CONFIDENCE WITH CURRENT LOW STRATUS CLOUD DECK THAT IS
COVERING A WIDE AREA ACROSS THE REGION. MOST MODELS ARE SHOWING
THAT THERE SHOULD BE LESS COVERAGE...SO HAVE TO USE OTHER TOOLS TO
GET A HANDLE ON IT. FORECASTED SOUNDINGS SHOW THAT INVERSION SHOULD
WORK DOWN AND THAT STRATUS MAY THIN THIS AFTERNOON.

FOR TONIGHT...WINDS LOOK TOO STRONG FOR FOG FORMATION BUT WILL
CONTINUE TO LOOK AT THIS POSSIBILITY. MAYBE IT WILL BE AN ELEVATED
ADVECTION FOG ISSUE. TFJ

PREVIOUS DISCUSSION...
SHALLOW STRATUS DECK REMAINS IN PLACE OVER EASTERN MONTANA THIS
MORNING. MOISTURE MOSTLY BELOW 850MB AS EVIDENCE BY 0Z GGW
SOUNDING AND SATELLITE SHOWING THE LITTLE ROCKIES AND BEARS PAWS
STICKING OUT OF THE CLOUD. MAIN FORECAST ISSUE WILL BE HOW LONG
DOES THE LOW CLOUD PERSIST. GIVEN THE INVERSION AND DRY AIR ALOFT
LITTLE MIXING IS EXPECTED BUT COULD SEE SOME SHALLOWING FOR MORE
OF THE HIGHER TERRAIN AREAS GETTING INTO THE CLOUD LAYER FOR FOG
OR GETTING ABOVE IT FOR CLEARING. SHORTWAVE MOVING TOWARD THE
REGION TONIGHT COULD RESULT IN ENOUGH TURBULENCE TO MIX OUT THE
LOW LEVEL MOISTURE.

SHORTWAVE DOES BRING TO ELEVATED MOISTURE AND LIFT ALONG A FRONTAL
BOUNDARY ON WEDNESDAY FOR A FEW SNOW SHOWERS. WESTERLY FLOW BEHIND
THE WAVE SHOULD RESULT IN SLIGHTLY WARMER TEMPERATURES IN THE
SOUTHWEST ZONES. EBERT


.LONG TERM...THURSDAY NIGHT THROUGH TUESDAY...

SYNOPTIC SET UP... WITH WEAK POOLED COLD AIR AT THE SURFACE OVER
THE EASTERN GREAT PLAINS. A RIDGE RUNS UP THE COAST FROM
CALIFORNIA TO SOUTHERN BRITISH COLUMBIA. NORTHEAST MONTANA LIES
BETWEEN THESE TWO FEATURES IN A UNENERGETIC WEAK NORTHWESTERN FLOW.
COLDEST AIR OF THE NORTHERN HEMISPHERE LIES BOTTLED UP OVER THE
ARCTIC.

THURSDAY NIGHT THROUGH SUNDAY... RIDGE TO THE WEST GAINS
INCREASING INFLUENCE AND PLACES NORTHEAST MONTANA UNDER PARTLY
CLOUDY AND DRY CONDITIONS DUE TO A STABLE ATMOSPHERE. SUBTLE
SHORTWAVES APPEAR IN THE FLOW... ESPECIALLY ON SATURDAY... BUT
REMAIN RELATIVELY UN-ENERGIZED AND SEEM INSUFFICIENT TO CAUSE
PRECIPITATION AT THIS TIME.

SUNDAY NIGHT ONWARD... WESTERN RIDGE WILL FINALLY MOVE THROUGH
THE AREA AND GENERATE CONDITIONS FOR A PREFRONTAL WARMING SPIKE
ON SUNDAY NIGHT. BY MONDAY AN ARCTIC INTRUSION IS ANTICIPATED TO
BEGIN AND WILL BRING A COLD FRONT THROUGH THE REGION. POSSIBLE
PACIFIC MOISTURE AT THE CREST OF THE EXITING RIDGE COULD HELP TO
GENERATE SHOWER STARTING DURING THIS PERIOD AND LASTING THROUGH
TUESDAY. AFTERWARD TEMPERATURES ARE EXPECTED TO BEGIN DROPPING
OFF.

GAH

&&

.AVIATION...
MVFR STRATUS WILL CONTINUE OVER THE TAF SITES FOR THE REST OF THIS
MORNING. A FEW BREAKS MAY OCCUR THIS AFTERNOON BUT CONFIDENCE IS
LOW. SOUTHEAST WINDS WILL HOVER AROUND 10 KTS. MALIAWCO


&&

.GLASGOW WATCHES/WARNINGS/ADVISORIES...NONE.

&&

$$

WEATHER.GOV/GLASGOW






000
FXUS65 KTFX 161215
AFDTFX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREAT FALLS MT
510 AM MST Tue Dec 16 2014

.DISCUSSION...

Today through Thursday...Forecast for the short term period is
expected to remain foggy this morning. Have expanded the Freezing
Fog Advisory to include Cascade and Judith Basin Counties as well
as the Rocky Mountain based on latest observations and SPORT night
time microphysics RGB imagery. Shortwave energy is still on track
to push into southwest Montana today and then into central Montana
overnight. Have increased PoPs across portions of the forecast
area based upon NAM model run but do not anticipated that snowfall
will be widespread enough or heavy enough to require any type of
highlights. Temperatures will remain near or below seasonal
averages for this time of year but I have undercut office-derived
SuperBlend temperature guidance for today and Wednesday given poor
performance on Monday. Expect another lull in clouds and
precipitation Wednesday night into Thursday before the progressive
pattern aloft brings another shortwave into western portions of
the forecast area Thursday afternoon. mpj

Thursday Night through Tuesday...A weak upper level ridge of high
pressure will keep the forecast area mostly dry Thursday night and
Friday. A shortwave trough will then move into the area Friday night
into Saturday, bringing an increased chance of mountain snow.
However, breezy westerly downslope winds will keep the plains dry.
The weather pattern will change somewhat beginning on Sunday. An
upper level ridge of high pressure will strengthen off the
California coast and an upper level trough of low pressure will
deepen from Hudson Bay into the Great Lakes. This will put Montana
under the influence of a strong northwesterly flow aloft. The
strongest winds aloft (60 to 70 kt at 700 mb) will occur Sunday into
Monday with the passage of a disturbance embedded in the flow. This
set-up will bring gusty westerly downslope winds to much of the
area, but especially over the plains of north central Montana. In
fact, some areas along the Rocky Mountain Front could approach High
Wind criteria (40 mph sustained/58 mph gusts). Confidence is
increasing that High Wind highlights may be needed for this event.
There is also significant moisture with this disturbance, so have
increased the chance for precipitation out onto the plains. Although
the winds will decrease somewhat after the passage of the
disturbance, the northwesterly flow aloft will remain fairly moist,
so have kept the chance for precipitation above climatological
normals across the area into Tuesday. The breezy winds throughout
the period will keep temperatures around 10 degrees above normal.
The warmest day of the period appears to be Monday, when most lower
elevation locations should get well into the 40s.
Coulston

&&

.AVIATION...
UPDATED 1210Z.
Low clouds with areas of dense fog will likely begin to erode
somewhat after 16Z across the plains of north central today.
Ceilings will mostly be IFR/LIFR, but the dense fog over the
western plains (including KGTF KCTB) is causing VLIFR conditions.
Conditions should improve in the west first, then ceilings will
gradually lift and clouds will break up after 18Z. However, KLWT is
out of the fog/low clouds at this time, and they will likely stay
that way. A disturbance will move northeast into the area after 00Z,
bringing increasing high and mid level cloudiness from the southwest
after 18Z, then more mid level cloudiness and a chance of snow after
03Z in the southwest and after 06Z over central Montana. Occasional
MVFR conditions are possible with any snow.
Coulston

&&

.PRELIMINARY POINT TEMPS/POPS...
GTF  28  22  36  24 /   0  20  30  10
CTB  25  17  34  21 /   0  10  10  10
HLN  30  20  32  19 /  10  30  20  10
BZN  29  19  33  15 /  10  30  20  10
WEY  29  18  31  14 /  40  50  40  20
DLN  31  21  34  19 /  20  30  10  10
HVR  26  15  30  20 /   0  10  20  10
LWT  30  22  37  21 /   0  20  20  10

&&

.TFX WATCHES/WARNINGS/ADVISORIES...
FREEZING FOG ADVISORY until 11 AM MST this morning Cascade...
Eastern Glacier...Eastern Pondera...Eastern Teton...Judith
Basin...Northern Rocky Mountain Front...Southern Rocky Mountain
Front...Toole.

&&

$$

weather.gov/greatfalls
www.twitter.com/NWSGreatFalls
www.facebook.com/NWSGreatFalls







000
FXUS65 KTFX 161215
AFDTFX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREAT FALLS MT
510 AM MST Tue Dec 16 2014

.DISCUSSION...

Today through Thursday...Forecast for the short term period is
expected to remain foggy this morning. Have expanded the Freezing
Fog Advisory to include Cascade and Judith Basin Counties as well
as the Rocky Mountain based on latest observations and SPORT night
time microphysics RGB imagery. Shortwave energy is still on track
to push into southwest Montana today and then into central Montana
overnight. Have increased PoPs across portions of the forecast
area based upon NAM model run but do not anticipated that snowfall
will be widespread enough or heavy enough to require any type of
highlights. Temperatures will remain near or below seasonal
averages for this time of year but I have undercut office-derived
SuperBlend temperature guidance for today and Wednesday given poor
performance on Monday. Expect another lull in clouds and
precipitation Wednesday night into Thursday before the progressive
pattern aloft brings another shortwave into western portions of
the forecast area Thursday afternoon. mpj

Thursday Night through Tuesday...A weak upper level ridge of high
pressure will keep the forecast area mostly dry Thursday night and
Friday. A shortwave trough will then move into the area Friday night
into Saturday, bringing an increased chance of mountain snow.
However, breezy westerly downslope winds will keep the plains dry.
The weather pattern will change somewhat beginning on Sunday. An
upper level ridge of high pressure will strengthen off the
California coast and an upper level trough of low pressure will
deepen from Hudson Bay into the Great Lakes. This will put Montana
under the influence of a strong northwesterly flow aloft. The
strongest winds aloft (60 to 70 kt at 700 mb) will occur Sunday into
Monday with the passage of a disturbance embedded in the flow. This
set-up will bring gusty westerly downslope winds to much of the
area, but especially over the plains of north central Montana. In
fact, some areas along the Rocky Mountain Front could approach High
Wind criteria (40 mph sustained/58 mph gusts). Confidence is
increasing that High Wind highlights may be needed for this event.
There is also significant moisture with this disturbance, so have
increased the chance for precipitation out onto the plains. Although
the winds will decrease somewhat after the passage of the
disturbance, the northwesterly flow aloft will remain fairly moist,
so have kept the chance for precipitation above climatological
normals across the area into Tuesday. The breezy winds throughout
the period will keep temperatures around 10 degrees above normal.
The warmest day of the period appears to be Monday, when most lower
elevation locations should get well into the 40s.
Coulston

&&

.AVIATION...
UPDATED 1210Z.
Low clouds with areas of dense fog will likely begin to erode
somewhat after 16Z across the plains of north central today.
Ceilings will mostly be IFR/LIFR, but the dense fog over the
western plains (including KGTF KCTB) is causing VLIFR conditions.
Conditions should improve in the west first, then ceilings will
gradually lift and clouds will break up after 18Z. However, KLWT is
out of the fog/low clouds at this time, and they will likely stay
that way. A disturbance will move northeast into the area after 00Z,
bringing increasing high and mid level cloudiness from the southwest
after 18Z, then more mid level cloudiness and a chance of snow after
03Z in the southwest and after 06Z over central Montana. Occasional
MVFR conditions are possible with any snow.
Coulston

&&

.PRELIMINARY POINT TEMPS/POPS...
GTF  28  22  36  24 /   0  20  30  10
CTB  25  17  34  21 /   0  10  10  10
HLN  30  20  32  19 /  10  30  20  10
BZN  29  19  33  15 /  10  30  20  10
WEY  29  18  31  14 /  40  50  40  20
DLN  31  21  34  19 /  20  30  10  10
HVR  26  15  30  20 /   0  10  20  10
LWT  30  22  37  21 /   0  20  20  10

&&

.TFX WATCHES/WARNINGS/ADVISORIES...
FREEZING FOG ADVISORY until 11 AM MST this morning Cascade...
Eastern Glacier...Eastern Pondera...Eastern Teton...Judith
Basin...Northern Rocky Mountain Front...Southern Rocky Mountain
Front...Toole.

&&

$$

weather.gov/greatfalls
www.twitter.com/NWSGreatFalls
www.facebook.com/NWSGreatFalls








000
FXUS65 KBYZ 161143
AFDBYZ

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE BILLINGS MT
443 AM MST TUE DEC 16 2014

.SHORT TERM...VALID FOR TDY AND WED...

MAIN FORECAST PROBLEM FOR THE SHORT TERM CONCERNS CONSIDERABLE
AREAS OF FOG ACROSS THE FORECAST AREA...PARTICULARLY IN THE
LOWER ELEVATIONS OF THE WESTERN ZONES. THE PATTERN FAVORS THIS TO
CONTINUE WITH A RIDGE ALOFT AND SURFACE LOW PRESSURE TO OUR
WEST/SOUTHWEST THIS IS KEEPING A SOUTHEAST LOW LEVEL FLOW
UPSLOPING INTO SOUTH CENTRAL MONTANA. LOCAL OBSERVATIONS SHOW A
QUARTER MILE VISIBILITY OR LESS IN AREAS JUST WEST OF BILLINGS TO
LIVINGSTON AND UP TO JUDITH GAP. MESOSCALE CROSS SECTIONS SHOW
THIS PERSISTING THROUGH MUCH OF THE MORNING FOR THIS AREA...AND
PERHAPS EVEN INTO THE AFTERNOON FOR PARK COUNTY AROUND LIVINGSTON.
THIS WILL ALSO TEND TO PREVENT MUCH IF ANY SOLAR RADIATION FOR
MUCH OF THE DAY AND SINCE MOS GUIDANCE IS NOT TAKING IT INTO
ACCOUNT I WILL BE SURE TO UNDERCUT GUIDANCE IN THESE AREAS. MAIN
MESSAGE...FOGGY AND CONTINUED CHILLY MOST LOCATIONS TODAY.

DENSE FOG ADVISORY...ISSUED ACROSS AREAS GENERALLY FROM LIVINGSTON
TO BIG TIMBER AND UP TO JUDITH GAP WHERE OBSERVATIONS INDICATE
PERSISTENT DENSE FOG. LOCALLY ICY ROADS WILL MAKE THIS EVEN MORE
DANGEROUS. AS MENTIONED BEFORE PROGGS SUGGEST THE WIDESPREAD FOG
WILL LINGER IN THESE AREAS UNTIL ABOUT 18Z.

IN THE MEANTIME...THE 500MB RIDGE BUILDING OVER US NOW WILL
QUICKLY BREAK DOWN LATE TODAY AND TONIGHT AS ANOTHER BROAD SPLIT
FLOW TROUGH MOVES INTO THE WESTERN UNITED STATES. A WEAKER SHORT
WAVE IN THE MEAN FLOW WILL SPLIT FROM THE SOUTHERN BRANCH AND
TRACK OVER OUR REGION TONIGHT AND INTO WEDNESDAY. QPF PROGGS ARE
NOT IMPRESSIVE BUT SEEMS PRUDENT TO BUMP UP SOME OF THE POPS NOW
FOR THE HIGH COUNTRY. WE MAY SEE SOME FLURRIES OR LIGHT SNOW IN
THE EAST AS IT MOVES THROUGH WEDNESDAY MORNING AS WELL. LOOK FOR A
MODEST WARM UP TO AROUND SEASONAL AVERAGES FOR WEDNESDAY. BT

.LONG TERM...VALID FOR THU...FRI...SAT...SUN...MON...

ENSEMBLE FORECASTS FROM THE GFS AND ECMWF WERE SHOWING MORE
CONFIDENCE IN THEIR SOLUTIONS FOR THE EXTENDED PERIOD THAN THEY
HAVE IN PREVIOUS RUNS.

FLOW GENERALLY BECOMES MORE PROGRESSIVE WITH TIME. WEAK NORTHERN
STREAM OF A PACIFIC TROUGH WILL BE OVER THE REGION ON THU. THIS
WILL BE FOLLOWED BY A SHORTWAVE RIDGE ON FRI AND ANOTHER WEAK
TROUGH FOR SAT. WENT WITH SUPER BLEND POPS FOR THIS PERIOD WHERE
MOISTURE AFFECTS MAINLY THE MOUNTAINS. A STRONG PACIFIC JET WILL
MOVE INTO THE REGION LATE IN THE PERIOD WHICH RESULTS IN A FAST
WNW FLOW OVERTAKING THE AREA BEGINNING ON SUN. ENERGY WILL MOVE
THROUGH THIS FLOW ALONG WITH PERIODS OF PACIFIC MOISTURE. GEFS
SHOWED AN ATMOSPHERIC RIVER WILL AFFECT THE REGION SUN INTO MON
WHICH WILL CONTRIBUTE TO PRECIPITATION CHANCES. HAVE INCREASED
POPS OVER THE AREA BEGINNING ON SUN. MAY HAVE GAP WIND ISSUES SAT
NIGHT INTO MON AS MODELS AGREED ON STRONG LEE TROUGHING OVER THE
AREA. WILL CONTINUE TO HAVE STRONG WINDS IN THE FORECAST FOR THE
GAP AREAS. THE MODELS WERE IN GOOD AGREEMENT WITH TEMPERATURES
THROUGH THE EXTENDED AND SHOWED ABOVE NORMAL READINGS. ARTHUR
&&

.AVIATION...

LIFR TO VLIFR CONDITIONS IN STRATUS AND FOG WILL PERSIST FROM
ROSEBUD COUNTY W THROUGH MID-MORNING...THEN CONDITIONS WILL
IMPROVE TO MVFR/VFR. E OF ROSEBUD COUNTY...EXPECT MVFR/IFR
CONDITIONS WITH LITTLE IMPROVEMENT THROUGH THE DAY. MVFR TO IFR
CONDITIONS ARE EXPECTED TONIGHT ACROSS THE AREA WITH LOWER
CONDITIONS POSSIBLE. MOUNTAIN OBSCURATIONS WILL BE WIDESPREAD
THROUGH TONIGHT. ARTHUR
&&

.PRELIMINARY POINT TEMP/POPS...

    TDY WED     THU     FRI     SAT     SUN     MON
-------------------------------------------------------
BIL 027 020/036 022/039 023/039 026/042 025/043 035/045
    0/E 11/B    01/B    10/U    11/B    12/W    23/W
LVM 030 024/042 023/042 022/041 026/043 026/043 033/045
    1/F 22/J    11/E    11/U    11/B    13/W    33/W
HDN 029 014/033 015/037 017/038 019/040 019/041 028/043
    0/E 01/B    01/B    10/U    01/B    11/B    23/W
MLS 027 015/030 017/036 019/037 018/038 022/039 028/042
    0/E 01/B    01/B    10/U    01/U    11/U    23/W
4BQ 030 015/033 016/040 018/040 016/041 020/042 027/043
    0/E 02/J    01/B    10/U    01/U    11/B    23/W
BHK 024 012/028 015/035 019/037 016/038 020/039 025/041
    0/E 02/J    11/B    11/U    01/U    11/B    23/W
SHR 028 015/036 016/038 016/038 019/040 019/041 026/042
    0/E 01/B    01/B    10/U    01/B    12/J    33/W

&&

.BYZ WATCHES/WARNINGS/ADVISORIES...
MT...DENSE FOG ADVISORY IN EFFECT UNTIL 11 AM MST THIS MORNING FOR
      ZONES 28-34-40-41-63-65.
WY...NONE.

&&

$$
WEATHER.GOV/BILLINGS




000
FXUS65 KBYZ 161143
AFDBYZ

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE BILLINGS MT
443 AM MST TUE DEC 16 2014

.SHORT TERM...VALID FOR TDY AND WED...

MAIN FORECAST PROBLEM FOR THE SHORT TERM CONCERNS CONSIDERABLE
AREAS OF FOG ACROSS THE FORECAST AREA...PARTICULARLY IN THE
LOWER ELEVATIONS OF THE WESTERN ZONES. THE PATTERN FAVORS THIS TO
CONTINUE WITH A RIDGE ALOFT AND SURFACE LOW PRESSURE TO OUR
WEST/SOUTHWEST THIS IS KEEPING A SOUTHEAST LOW LEVEL FLOW
UPSLOPING INTO SOUTH CENTRAL MONTANA. LOCAL OBSERVATIONS SHOW A
QUARTER MILE VISIBILITY OR LESS IN AREAS JUST WEST OF BILLINGS TO
LIVINGSTON AND UP TO JUDITH GAP. MESOSCALE CROSS SECTIONS SHOW
THIS PERSISTING THROUGH MUCH OF THE MORNING FOR THIS AREA...AND
PERHAPS EVEN INTO THE AFTERNOON FOR PARK COUNTY AROUND LIVINGSTON.
THIS WILL ALSO TEND TO PREVENT MUCH IF ANY SOLAR RADIATION FOR
MUCH OF THE DAY AND SINCE MOS GUIDANCE IS NOT TAKING IT INTO
ACCOUNT I WILL BE SURE TO UNDERCUT GUIDANCE IN THESE AREAS. MAIN
MESSAGE...FOGGY AND CONTINUED CHILLY MOST LOCATIONS TODAY.

DENSE FOG ADVISORY...ISSUED ACROSS AREAS GENERALLY FROM LIVINGSTON
TO BIG TIMBER AND UP TO JUDITH GAP WHERE OBSERVATIONS INDICATE
PERSISTENT DENSE FOG. LOCALLY ICY ROADS WILL MAKE THIS EVEN MORE
DANGEROUS. AS MENTIONED BEFORE PROGGS SUGGEST THE WIDESPREAD FOG
WILL LINGER IN THESE AREAS UNTIL ABOUT 18Z.

IN THE MEANTIME...THE 500MB RIDGE BUILDING OVER US NOW WILL
QUICKLY BREAK DOWN LATE TODAY AND TONIGHT AS ANOTHER BROAD SPLIT
FLOW TROUGH MOVES INTO THE WESTERN UNITED STATES. A WEAKER SHORT
WAVE IN THE MEAN FLOW WILL SPLIT FROM THE SOUTHERN BRANCH AND
TRACK OVER OUR REGION TONIGHT AND INTO WEDNESDAY. QPF PROGGS ARE
NOT IMPRESSIVE BUT SEEMS PRUDENT TO BUMP UP SOME OF THE POPS NOW
FOR THE HIGH COUNTRY. WE MAY SEE SOME FLURRIES OR LIGHT SNOW IN
THE EAST AS IT MOVES THROUGH WEDNESDAY MORNING AS WELL. LOOK FOR A
MODEST WARM UP TO AROUND SEASONAL AVERAGES FOR WEDNESDAY. BT

.LONG TERM...VALID FOR THU...FRI...SAT...SUN...MON...

ENSEMBLE FORECASTS FROM THE GFS AND ECMWF WERE SHOWING MORE
CONFIDENCE IN THEIR SOLUTIONS FOR THE EXTENDED PERIOD THAN THEY
HAVE IN PREVIOUS RUNS.

FLOW GENERALLY BECOMES MORE PROGRESSIVE WITH TIME. WEAK NORTHERN
STREAM OF A PACIFIC TROUGH WILL BE OVER THE REGION ON THU. THIS
WILL BE FOLLOWED BY A SHORTWAVE RIDGE ON FRI AND ANOTHER WEAK
TROUGH FOR SAT. WENT WITH SUPER BLEND POPS FOR THIS PERIOD WHERE
MOISTURE AFFECTS MAINLY THE MOUNTAINS. A STRONG PACIFIC JET WILL
MOVE INTO THE REGION LATE IN THE PERIOD WHICH RESULTS IN A FAST
WNW FLOW OVERTAKING THE AREA BEGINNING ON SUN. ENERGY WILL MOVE
THROUGH THIS FLOW ALONG WITH PERIODS OF PACIFIC MOISTURE. GEFS
SHOWED AN ATMOSPHERIC RIVER WILL AFFECT THE REGION SUN INTO MON
WHICH WILL CONTRIBUTE TO PRECIPITATION CHANCES. HAVE INCREASED
POPS OVER THE AREA BEGINNING ON SUN. MAY HAVE GAP WIND ISSUES SAT
NIGHT INTO MON AS MODELS AGREED ON STRONG LEE TROUGHING OVER THE
AREA. WILL CONTINUE TO HAVE STRONG WINDS IN THE FORECAST FOR THE
GAP AREAS. THE MODELS WERE IN GOOD AGREEMENT WITH TEMPERATURES
THROUGH THE EXTENDED AND SHOWED ABOVE NORMAL READINGS. ARTHUR
&&

.AVIATION...

LIFR TO VLIFR CONDITIONS IN STRATUS AND FOG WILL PERSIST FROM
ROSEBUD COUNTY W THROUGH MID-MORNING...THEN CONDITIONS WILL
IMPROVE TO MVFR/VFR. E OF ROSEBUD COUNTY...EXPECT MVFR/IFR
CONDITIONS WITH LITTLE IMPROVEMENT THROUGH THE DAY. MVFR TO IFR
CONDITIONS ARE EXPECTED TONIGHT ACROSS THE AREA WITH LOWER
CONDITIONS POSSIBLE. MOUNTAIN OBSCURATIONS WILL BE WIDESPREAD
THROUGH TONIGHT. ARTHUR
&&

.PRELIMINARY POINT TEMP/POPS...

    TDY WED     THU     FRI     SAT     SUN     MON
-------------------------------------------------------
BIL 027 020/036 022/039 023/039 026/042 025/043 035/045
    0/E 11/B    01/B    10/U    11/B    12/W    23/W
LVM 030 024/042 023/042 022/041 026/043 026/043 033/045
    1/F 22/J    11/E    11/U    11/B    13/W    33/W
HDN 029 014/033 015/037 017/038 019/040 019/041 028/043
    0/E 01/B    01/B    10/U    01/B    11/B    23/W
MLS 027 015/030 017/036 019/037 018/038 022/039 028/042
    0/E 01/B    01/B    10/U    01/U    11/U    23/W
4BQ 030 015/033 016/040 018/040 016/041 020/042 027/043
    0/E 02/J    01/B    10/U    01/U    11/B    23/W
BHK 024 012/028 015/035 019/037 016/038 020/039 025/041
    0/E 02/J    11/B    11/U    01/U    11/B    23/W
SHR 028 015/036 016/038 016/038 019/040 019/041 026/042
    0/E 01/B    01/B    10/U    01/B    12/J    33/W

&&

.BYZ WATCHES/WARNINGS/ADVISORIES...
MT...DENSE FOG ADVISORY IN EFFECT UNTIL 11 AM MST THIS MORNING FOR
      ZONES 28-34-40-41-63-65.
WY...NONE.

&&

$$
WEATHER.GOV/BILLINGS




000
FXUS65 KBYZ 161143
AFDBYZ

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE BILLINGS MT
443 AM MST TUE DEC 16 2014

.SHORT TERM...VALID FOR TDY AND WED...

MAIN FORECAST PROBLEM FOR THE SHORT TERM CONCERNS CONSIDERABLE
AREAS OF FOG ACROSS THE FORECAST AREA...PARTICULARLY IN THE
LOWER ELEVATIONS OF THE WESTERN ZONES. THE PATTERN FAVORS THIS TO
CONTINUE WITH A RIDGE ALOFT AND SURFACE LOW PRESSURE TO OUR
WEST/SOUTHWEST THIS IS KEEPING A SOUTHEAST LOW LEVEL FLOW
UPSLOPING INTO SOUTH CENTRAL MONTANA. LOCAL OBSERVATIONS SHOW A
QUARTER MILE VISIBILITY OR LESS IN AREAS JUST WEST OF BILLINGS TO
LIVINGSTON AND UP TO JUDITH GAP. MESOSCALE CROSS SECTIONS SHOW
THIS PERSISTING THROUGH MUCH OF THE MORNING FOR THIS AREA...AND
PERHAPS EVEN INTO THE AFTERNOON FOR PARK COUNTY AROUND LIVINGSTON.
THIS WILL ALSO TEND TO PREVENT MUCH IF ANY SOLAR RADIATION FOR
MUCH OF THE DAY AND SINCE MOS GUIDANCE IS NOT TAKING IT INTO
ACCOUNT I WILL BE SURE TO UNDERCUT GUIDANCE IN THESE AREAS. MAIN
MESSAGE...FOGGY AND CONTINUED CHILLY MOST LOCATIONS TODAY.

DENSE FOG ADVISORY...ISSUED ACROSS AREAS GENERALLY FROM LIVINGSTON
TO BIG TIMBER AND UP TO JUDITH GAP WHERE OBSERVATIONS INDICATE
PERSISTENT DENSE FOG. LOCALLY ICY ROADS WILL MAKE THIS EVEN MORE
DANGEROUS. AS MENTIONED BEFORE PROGGS SUGGEST THE WIDESPREAD FOG
WILL LINGER IN THESE AREAS UNTIL ABOUT 18Z.

IN THE MEANTIME...THE 500MB RIDGE BUILDING OVER US NOW WILL
QUICKLY BREAK DOWN LATE TODAY AND TONIGHT AS ANOTHER BROAD SPLIT
FLOW TROUGH MOVES INTO THE WESTERN UNITED STATES. A WEAKER SHORT
WAVE IN THE MEAN FLOW WILL SPLIT FROM THE SOUTHERN BRANCH AND
TRACK OVER OUR REGION TONIGHT AND INTO WEDNESDAY. QPF PROGGS ARE
NOT IMPRESSIVE BUT SEEMS PRUDENT TO BUMP UP SOME OF THE POPS NOW
FOR THE HIGH COUNTRY. WE MAY SEE SOME FLURRIES OR LIGHT SNOW IN
THE EAST AS IT MOVES THROUGH WEDNESDAY MORNING AS WELL. LOOK FOR A
MODEST WARM UP TO AROUND SEASONAL AVERAGES FOR WEDNESDAY. BT

.LONG TERM...VALID FOR THU...FRI...SAT...SUN...MON...

ENSEMBLE FORECASTS FROM THE GFS AND ECMWF WERE SHOWING MORE
CONFIDENCE IN THEIR SOLUTIONS FOR THE EXTENDED PERIOD THAN THEY
HAVE IN PREVIOUS RUNS.

FLOW GENERALLY BECOMES MORE PROGRESSIVE WITH TIME. WEAK NORTHERN
STREAM OF A PACIFIC TROUGH WILL BE OVER THE REGION ON THU. THIS
WILL BE FOLLOWED BY A SHORTWAVE RIDGE ON FRI AND ANOTHER WEAK
TROUGH FOR SAT. WENT WITH SUPER BLEND POPS FOR THIS PERIOD WHERE
MOISTURE AFFECTS MAINLY THE MOUNTAINS. A STRONG PACIFIC JET WILL
MOVE INTO THE REGION LATE IN THE PERIOD WHICH RESULTS IN A FAST
WNW FLOW OVERTAKING THE AREA BEGINNING ON SUN. ENERGY WILL MOVE
THROUGH THIS FLOW ALONG WITH PERIODS OF PACIFIC MOISTURE. GEFS
SHOWED AN ATMOSPHERIC RIVER WILL AFFECT THE REGION SUN INTO MON
WHICH WILL CONTRIBUTE TO PRECIPITATION CHANCES. HAVE INCREASED
POPS OVER THE AREA BEGINNING ON SUN. MAY HAVE GAP WIND ISSUES SAT
NIGHT INTO MON AS MODELS AGREED ON STRONG LEE TROUGHING OVER THE
AREA. WILL CONTINUE TO HAVE STRONG WINDS IN THE FORECAST FOR THE
GAP AREAS. THE MODELS WERE IN GOOD AGREEMENT WITH TEMPERATURES
THROUGH THE EXTENDED AND SHOWED ABOVE NORMAL READINGS. ARTHUR
&&

.AVIATION...

LIFR TO VLIFR CONDITIONS IN STRATUS AND FOG WILL PERSIST FROM
ROSEBUD COUNTY W THROUGH MID-MORNING...THEN CONDITIONS WILL
IMPROVE TO MVFR/VFR. E OF ROSEBUD COUNTY...EXPECT MVFR/IFR
CONDITIONS WITH LITTLE IMPROVEMENT THROUGH THE DAY. MVFR TO IFR
CONDITIONS ARE EXPECTED TONIGHT ACROSS THE AREA WITH LOWER
CONDITIONS POSSIBLE. MOUNTAIN OBSCURATIONS WILL BE WIDESPREAD
THROUGH TONIGHT. ARTHUR
&&

.PRELIMINARY POINT TEMP/POPS...

    TDY WED     THU     FRI     SAT     SUN     MON
-------------------------------------------------------
BIL 027 020/036 022/039 023/039 026/042 025/043 035/045
    0/E 11/B    01/B    10/U    11/B    12/W    23/W
LVM 030 024/042 023/042 022/041 026/043 026/043 033/045
    1/F 22/J    11/E    11/U    11/B    13/W    33/W
HDN 029 014/033 015/037 017/038 019/040 019/041 028/043
    0/E 01/B    01/B    10/U    01/B    11/B    23/W
MLS 027 015/030 017/036 019/037 018/038 022/039 028/042
    0/E 01/B    01/B    10/U    01/U    11/U    23/W
4BQ 030 015/033 016/040 018/040 016/041 020/042 027/043
    0/E 02/J    01/B    10/U    01/U    11/B    23/W
BHK 024 012/028 015/035 019/037 016/038 020/039 025/041
    0/E 02/J    11/B    11/U    01/U    11/B    23/W
SHR 028 015/036 016/038 016/038 019/040 019/041 026/042
    0/E 01/B    01/B    10/U    01/B    12/J    33/W

&&

.BYZ WATCHES/WARNINGS/ADVISORIES...
MT...DENSE FOG ADVISORY IN EFFECT UNTIL 11 AM MST THIS MORNING FOR
      ZONES 28-34-40-41-63-65.
WY...NONE.

&&

$$
WEATHER.GOV/BILLINGS




000
FXUS65 KBYZ 161143
AFDBYZ

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE BILLINGS MT
443 AM MST TUE DEC 16 2014

.SHORT TERM...VALID FOR TDY AND WED...

MAIN FORECAST PROBLEM FOR THE SHORT TERM CONCERNS CONSIDERABLE
AREAS OF FOG ACROSS THE FORECAST AREA...PARTICULARLY IN THE
LOWER ELEVATIONS OF THE WESTERN ZONES. THE PATTERN FAVORS THIS TO
CONTINUE WITH A RIDGE ALOFT AND SURFACE LOW PRESSURE TO OUR
WEST/SOUTHWEST THIS IS KEEPING A SOUTHEAST LOW LEVEL FLOW
UPSLOPING INTO SOUTH CENTRAL MONTANA. LOCAL OBSERVATIONS SHOW A
QUARTER MILE VISIBILITY OR LESS IN AREAS JUST WEST OF BILLINGS TO
LIVINGSTON AND UP TO JUDITH GAP. MESOSCALE CROSS SECTIONS SHOW
THIS PERSISTING THROUGH MUCH OF THE MORNING FOR THIS AREA...AND
PERHAPS EVEN INTO THE AFTERNOON FOR PARK COUNTY AROUND LIVINGSTON.
THIS WILL ALSO TEND TO PREVENT MUCH IF ANY SOLAR RADIATION FOR
MUCH OF THE DAY AND SINCE MOS GUIDANCE IS NOT TAKING IT INTO
ACCOUNT I WILL BE SURE TO UNDERCUT GUIDANCE IN THESE AREAS. MAIN
MESSAGE...FOGGY AND CONTINUED CHILLY MOST LOCATIONS TODAY.

DENSE FOG ADVISORY...ISSUED ACROSS AREAS GENERALLY FROM LIVINGSTON
TO BIG TIMBER AND UP TO JUDITH GAP WHERE OBSERVATIONS INDICATE
PERSISTENT DENSE FOG. LOCALLY ICY ROADS WILL MAKE THIS EVEN MORE
DANGEROUS. AS MENTIONED BEFORE PROGGS SUGGEST THE WIDESPREAD FOG
WILL LINGER IN THESE AREAS UNTIL ABOUT 18Z.

IN THE MEANTIME...THE 500MB RIDGE BUILDING OVER US NOW WILL
QUICKLY BREAK DOWN LATE TODAY AND TONIGHT AS ANOTHER BROAD SPLIT
FLOW TROUGH MOVES INTO THE WESTERN UNITED STATES. A WEAKER SHORT
WAVE IN THE MEAN FLOW WILL SPLIT FROM THE SOUTHERN BRANCH AND
TRACK OVER OUR REGION TONIGHT AND INTO WEDNESDAY. QPF PROGGS ARE
NOT IMPRESSIVE BUT SEEMS PRUDENT TO BUMP UP SOME OF THE POPS NOW
FOR THE HIGH COUNTRY. WE MAY SEE SOME FLURRIES OR LIGHT SNOW IN
THE EAST AS IT MOVES THROUGH WEDNESDAY MORNING AS WELL. LOOK FOR A
MODEST WARM UP TO AROUND SEASONAL AVERAGES FOR WEDNESDAY. BT

.LONG TERM...VALID FOR THU...FRI...SAT...SUN...MON...

ENSEMBLE FORECASTS FROM THE GFS AND ECMWF WERE SHOWING MORE
CONFIDENCE IN THEIR SOLUTIONS FOR THE EXTENDED PERIOD THAN THEY
HAVE IN PREVIOUS RUNS.

FLOW GENERALLY BECOMES MORE PROGRESSIVE WITH TIME. WEAK NORTHERN
STREAM OF A PACIFIC TROUGH WILL BE OVER THE REGION ON THU. THIS
WILL BE FOLLOWED BY A SHORTWAVE RIDGE ON FRI AND ANOTHER WEAK
TROUGH FOR SAT. WENT WITH SUPER BLEND POPS FOR THIS PERIOD WHERE
MOISTURE AFFECTS MAINLY THE MOUNTAINS. A STRONG PACIFIC JET WILL
MOVE INTO THE REGION LATE IN THE PERIOD WHICH RESULTS IN A FAST
WNW FLOW OVERTAKING THE AREA BEGINNING ON SUN. ENERGY WILL MOVE
THROUGH THIS FLOW ALONG WITH PERIODS OF PACIFIC MOISTURE. GEFS
SHOWED AN ATMOSPHERIC RIVER WILL AFFECT THE REGION SUN INTO MON
WHICH WILL CONTRIBUTE TO PRECIPITATION CHANCES. HAVE INCREASED
POPS OVER THE AREA BEGINNING ON SUN. MAY HAVE GAP WIND ISSUES SAT
NIGHT INTO MON AS MODELS AGREED ON STRONG LEE TROUGHING OVER THE
AREA. WILL CONTINUE TO HAVE STRONG WINDS IN THE FORECAST FOR THE
GAP AREAS. THE MODELS WERE IN GOOD AGREEMENT WITH TEMPERATURES
THROUGH THE EXTENDED AND SHOWED ABOVE NORMAL READINGS. ARTHUR
&&

.AVIATION...

LIFR TO VLIFR CONDITIONS IN STRATUS AND FOG WILL PERSIST FROM
ROSEBUD COUNTY W THROUGH MID-MORNING...THEN CONDITIONS WILL
IMPROVE TO MVFR/VFR. E OF ROSEBUD COUNTY...EXPECT MVFR/IFR
CONDITIONS WITH LITTLE IMPROVEMENT THROUGH THE DAY. MVFR TO IFR
CONDITIONS ARE EXPECTED TONIGHT ACROSS THE AREA WITH LOWER
CONDITIONS POSSIBLE. MOUNTAIN OBSCURATIONS WILL BE WIDESPREAD
THROUGH TONIGHT. ARTHUR
&&

.PRELIMINARY POINT TEMP/POPS...

    TDY WED     THU     FRI     SAT     SUN     MON
-------------------------------------------------------
BIL 027 020/036 022/039 023/039 026/042 025/043 035/045
    0/E 11/B    01/B    10/U    11/B    12/W    23/W
LVM 030 024/042 023/042 022/041 026/043 026/043 033/045
    1/F 22/J    11/E    11/U    11/B    13/W    33/W
HDN 029 014/033 015/037 017/038 019/040 019/041 028/043
    0/E 01/B    01/B    10/U    01/B    11/B    23/W
MLS 027 015/030 017/036 019/037 018/038 022/039 028/042
    0/E 01/B    01/B    10/U    01/U    11/U    23/W
4BQ 030 015/033 016/040 018/040 016/041 020/042 027/043
    0/E 02/J    01/B    10/U    01/U    11/B    23/W
BHK 024 012/028 015/035 019/037 016/038 020/039 025/041
    0/E 02/J    11/B    11/U    01/U    11/B    23/W
SHR 028 015/036 016/038 016/038 019/040 019/041 026/042
    0/E 01/B    01/B    10/U    01/B    12/J    33/W

&&

.BYZ WATCHES/WARNINGS/ADVISORIES...
MT...DENSE FOG ADVISORY IN EFFECT UNTIL 11 AM MST THIS MORNING FOR
      ZONES 28-34-40-41-63-65.
WY...NONE.

&&

$$
WEATHER.GOV/BILLINGS




000
FXUS65 KGGW 161051
AFDGGW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GLASGOW MT
351 AM MST TUE DEC 16 2014

.SHORT TERM...FOR NORTHEAST MONTANA...TODAY THROUGH THURSDAY...
SHALLOW STRATUS DECK REMAINS IN PLACE OVER EASTERN MONTANA THIS
MORNING. MOISTURE MOSTLY BELOW 850MB AS EVIDENCE BY 0Z GGW
SOUNDING AND SATELLITE SHOWING THE LITTLE ROCKIES AND BEARS PAWS
STICKING OUT OF THE CLOUD. MAIN FORECAST ISSUE WILL BE HOW LONG
DOES THE LOW CLOUD PERSIST. GIVEN THE INVERSION AND DRY AIR ALOFT
LITTLE MIXING IS EXPECTED BUT COULD SEE SOME SHALLOWING FOR MORE
OF THE HIGHER TERRAIN AREAS GETTING INTO THE CLOUD LAYER FOR FOG
OR GETTING ABOVE IT FOR CLEARING. SHORTWAVE MOVING TOWARD THE
REGION TONIGHT COULD RESULT IN ENOUGH TURBULENCE TO MIX OUT THE
LOW LEVEL MOISTURE.

SHORTWAVE DOES BRING TO ELEVATED MOISTURE AND LIFT ALONG A FRONTAL
BOUNDARY ON WEDNESDAY FOR A FEW SNOW SHOWERS. WESTERLY FLOW BEHIND
THE WAVE SHOULD RESULT IN SLIGHTLY WARMER TEMPERATURES IN THE
SOUTHWEST ZONES. EBERT


.LONG TERM...THURSDAY NIGHT THROUGH TUESDAY...

SYNOPTIC SET UP... WITH WEAK POOLED COLD AIR AT THE SURFACE OVER
THE EASTERN GREAT PLAINS. A RIDGE RUNS UP THE COAST FROM
CALIFORNIA TO SOUTHERN BRITISH COLUMBIA. NORTHEAST MONTANA LIES
BETWEEN THESE TWO FEATURES IN A UNENERGETIC WEAK NORTHWESTERN FLOW.
COLDEST AIR OF THE NORTHERN HEMISPHERE LIES BOTTLED UP OVER THE
ARCTIC.

THURSDAY NIGHT THROUGH SUNDAY... RIDGE TO THE WEST GAINS
INCREASING INFLUENCE AND PLACES NORTHEAST MONTANA UNDER PARTLY
CLOUDY AND DRY CONDITIONS DUE TO A STABLE ATMOSPHERE. SUBTLE
SHORTWAVES APPEAR IN THE FLOW... ESPECIALLY ON SATURDAY... BUT
REMAIN RELATIVELY UN-ENERGIZED AND SEEM INSUFFICIENT TO CAUSE
PRECIPITATION AT THIS TIME.

SUNDAY NIGHT ONWARD... WESTERN RIDGE WILL FINALLY MOVE THROUGH
THE AREA AND GENERATE CONDITIONS FOR A PREFRONTAL WARMING SPIKE
ON SUNDAY NIGHT. BY MONDAY AN ARCTIC INTRUSION IS ANTICIPATED TO
BEGIN AND WILL BRING A COLD FRONT THROUGH THE REGION. POSSIBLE
PACIFIC MOISTURE AT THE CREST OF THE EXITING RIDGE COULD HELP TO
GENERATE SHOWER STARTING DURING THIS PERIOD AND LASTING THROUGH
TUESDAY. AFTERWARD TEMPERATURES ARE EXPECTED TO BEGIN DROPPING
OFF.

GAH

&&

.AVIATION...

FLIGHT CATEGORY: MVFR

SYNOPSIS: TERMINALS WILL CONTINUE TO BE SOCKED IN BY WIDESPREAD LOW
LEVEL STRATUS. FUEL LOADING IS LIKELY FOR MOST SITES. SMALL
BREAKS IN THE STRATUS MAY BEGIN TO APPEAR  THIS AFTERNOON...
BUT FULL CLEARING MAY NOT OCCUR UNTIL MID WEEK.

AREA WINDS: LIGHT AND VARIABLE OVERNIGHT... BECOMING SOUTHEAST
AROUND 5 TO 10 KTS BY THE LATE MORNING.

GAH


&&

.GLASGOW WATCHES/WARNINGS/ADVISORIES...NONE.

&&

$$

WEATHER.GOV/GLASGOW






000
FXUS65 KGGW 161051
AFDGGW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GLASGOW MT
351 AM MST TUE DEC 16 2014

.SHORT TERM...FOR NORTHEAST MONTANA...TODAY THROUGH THURSDAY...
SHALLOW STRATUS DECK REMAINS IN PLACE OVER EASTERN MONTANA THIS
MORNING. MOISTURE MOSTLY BELOW 850MB AS EVIDENCE BY 0Z GGW
SOUNDING AND SATELLITE SHOWING THE LITTLE ROCKIES AND BEARS PAWS
STICKING OUT OF THE CLOUD. MAIN FORECAST ISSUE WILL BE HOW LONG
DOES THE LOW CLOUD PERSIST. GIVEN THE INVERSION AND DRY AIR ALOFT
LITTLE MIXING IS EXPECTED BUT COULD SEE SOME SHALLOWING FOR MORE
OF THE HIGHER TERRAIN AREAS GETTING INTO THE CLOUD LAYER FOR FOG
OR GETTING ABOVE IT FOR CLEARING. SHORTWAVE MOVING TOWARD THE
REGION TONIGHT COULD RESULT IN ENOUGH TURBULENCE TO MIX OUT THE
LOW LEVEL MOISTURE.

SHORTWAVE DOES BRING TO ELEVATED MOISTURE AND LIFT ALONG A FRONTAL
BOUNDARY ON WEDNESDAY FOR A FEW SNOW SHOWERS. WESTERLY FLOW BEHIND
THE WAVE SHOULD RESULT IN SLIGHTLY WARMER TEMPERATURES IN THE
SOUTHWEST ZONES. EBERT


.LONG TERM...THURSDAY NIGHT THROUGH TUESDAY...

SYNOPTIC SET UP... WITH WEAK POOLED COLD AIR AT THE SURFACE OVER
THE EASTERN GREAT PLAINS. A RIDGE RUNS UP THE COAST FROM
CALIFORNIA TO SOUTHERN BRITISH COLUMBIA. NORTHEAST MONTANA LIES
BETWEEN THESE TWO FEATURES IN A UNENERGETIC WEAK NORTHWESTERN FLOW.
COLDEST AIR OF THE NORTHERN HEMISPHERE LIES BOTTLED UP OVER THE
ARCTIC.

THURSDAY NIGHT THROUGH SUNDAY... RIDGE TO THE WEST GAINS
INCREASING INFLUENCE AND PLACES NORTHEAST MONTANA UNDER PARTLY
CLOUDY AND DRY CONDITIONS DUE TO A STABLE ATMOSPHERE. SUBTLE
SHORTWAVES APPEAR IN THE FLOW... ESPECIALLY ON SATURDAY... BUT
REMAIN RELATIVELY UN-ENERGIZED AND SEEM INSUFFICIENT TO CAUSE
PRECIPITATION AT THIS TIME.

SUNDAY NIGHT ONWARD... WESTERN RIDGE WILL FINALLY MOVE THROUGH
THE AREA AND GENERATE CONDITIONS FOR A PREFRONTAL WARMING SPIKE
ON SUNDAY NIGHT. BY MONDAY AN ARCTIC INTRUSION IS ANTICIPATED TO
BEGIN AND WILL BRING A COLD FRONT THROUGH THE REGION. POSSIBLE
PACIFIC MOISTURE AT THE CREST OF THE EXITING RIDGE COULD HELP TO
GENERATE SHOWER STARTING DURING THIS PERIOD AND LASTING THROUGH
TUESDAY. AFTERWARD TEMPERATURES ARE EXPECTED TO BEGIN DROPPING
OFF.

GAH

&&

.AVIATION...

FLIGHT CATEGORY: MVFR

SYNOPSIS: TERMINALS WILL CONTINUE TO BE SOCKED IN BY WIDESPREAD LOW
LEVEL STRATUS. FUEL LOADING IS LIKELY FOR MOST SITES. SMALL
BREAKS IN THE STRATUS MAY BEGIN TO APPEAR  THIS AFTERNOON...
BUT FULL CLEARING MAY NOT OCCUR UNTIL MID WEEK.

AREA WINDS: LIGHT AND VARIABLE OVERNIGHT... BECOMING SOUTHEAST
AROUND 5 TO 10 KTS BY THE LATE MORNING.

GAH


&&

.GLASGOW WATCHES/WARNINGS/ADVISORIES...NONE.

&&

$$

WEATHER.GOV/GLASGOW






000
FXUS65 KGGW 161051
AFDGGW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GLASGOW MT
351 AM MST TUE DEC 16 2014

.SHORT TERM...FOR NORTHEAST MONTANA...TODAY THROUGH THURSDAY...
SHALLOW STRATUS DECK REMAINS IN PLACE OVER EASTERN MONTANA THIS
MORNING. MOISTURE MOSTLY BELOW 850MB AS EVIDENCE BY 0Z GGW
SOUNDING AND SATELLITE SHOWING THE LITTLE ROCKIES AND BEARS PAWS
STICKING OUT OF THE CLOUD. MAIN FORECAST ISSUE WILL BE HOW LONG
DOES THE LOW CLOUD PERSIST. GIVEN THE INVERSION AND DRY AIR ALOFT
LITTLE MIXING IS EXPECTED BUT COULD SEE SOME SHALLOWING FOR MORE
OF THE HIGHER TERRAIN AREAS GETTING INTO THE CLOUD LAYER FOR FOG
OR GETTING ABOVE IT FOR CLEARING. SHORTWAVE MOVING TOWARD THE
REGION TONIGHT COULD RESULT IN ENOUGH TURBULENCE TO MIX OUT THE
LOW LEVEL MOISTURE.

SHORTWAVE DOES BRING TO ELEVATED MOISTURE AND LIFT ALONG A FRONTAL
BOUNDARY ON WEDNESDAY FOR A FEW SNOW SHOWERS. WESTERLY FLOW BEHIND
THE WAVE SHOULD RESULT IN SLIGHTLY WARMER TEMPERATURES IN THE
SOUTHWEST ZONES. EBERT


.LONG TERM...THURSDAY NIGHT THROUGH TUESDAY...

SYNOPTIC SET UP... WITH WEAK POOLED COLD AIR AT THE SURFACE OVER
THE EASTERN GREAT PLAINS. A RIDGE RUNS UP THE COAST FROM
CALIFORNIA TO SOUTHERN BRITISH COLUMBIA. NORTHEAST MONTANA LIES
BETWEEN THESE TWO FEATURES IN A UNENERGETIC WEAK NORTHWESTERN FLOW.
COLDEST AIR OF THE NORTHERN HEMISPHERE LIES BOTTLED UP OVER THE
ARCTIC.

THURSDAY NIGHT THROUGH SUNDAY... RIDGE TO THE WEST GAINS
INCREASING INFLUENCE AND PLACES NORTHEAST MONTANA UNDER PARTLY
CLOUDY AND DRY CONDITIONS DUE TO A STABLE ATMOSPHERE. SUBTLE
SHORTWAVES APPEAR IN THE FLOW... ESPECIALLY ON SATURDAY... BUT
REMAIN RELATIVELY UN-ENERGIZED AND SEEM INSUFFICIENT TO CAUSE
PRECIPITATION AT THIS TIME.

SUNDAY NIGHT ONWARD... WESTERN RIDGE WILL FINALLY MOVE THROUGH
THE AREA AND GENERATE CONDITIONS FOR A PREFRONTAL WARMING SPIKE
ON SUNDAY NIGHT. BY MONDAY AN ARCTIC INTRUSION IS ANTICIPATED TO
BEGIN AND WILL BRING A COLD FRONT THROUGH THE REGION. POSSIBLE
PACIFIC MOISTURE AT THE CREST OF THE EXITING RIDGE COULD HELP TO
GENERATE SHOWER STARTING DURING THIS PERIOD AND LASTING THROUGH
TUESDAY. AFTERWARD TEMPERATURES ARE EXPECTED TO BEGIN DROPPING
OFF.

GAH

&&

.AVIATION...

FLIGHT CATEGORY: MVFR

SYNOPSIS: TERMINALS WILL CONTINUE TO BE SOCKED IN BY WIDESPREAD LOW
LEVEL STRATUS. FUEL LOADING IS LIKELY FOR MOST SITES. SMALL
BREAKS IN THE STRATUS MAY BEGIN TO APPEAR  THIS AFTERNOON...
BUT FULL CLEARING MAY NOT OCCUR UNTIL MID WEEK.

AREA WINDS: LIGHT AND VARIABLE OVERNIGHT... BECOMING SOUTHEAST
AROUND 5 TO 10 KTS BY THE LATE MORNING.

GAH


&&

.GLASGOW WATCHES/WARNINGS/ADVISORIES...NONE.

&&

$$

WEATHER.GOV/GLASGOW






000
FXUS65 KGGW 161051
AFDGGW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GLASGOW MT
351 AM MST TUE DEC 16 2014

.SHORT TERM...FOR NORTHEAST MONTANA...TODAY THROUGH THURSDAY...
SHALLOW STRATUS DECK REMAINS IN PLACE OVER EASTERN MONTANA THIS
MORNING. MOISTURE MOSTLY BELOW 850MB AS EVIDENCE BY 0Z GGW
SOUNDING AND SATELLITE SHOWING THE LITTLE ROCKIES AND BEARS PAWS
STICKING OUT OF THE CLOUD. MAIN FORECAST ISSUE WILL BE HOW LONG
DOES THE LOW CLOUD PERSIST. GIVEN THE INVERSION AND DRY AIR ALOFT
LITTLE MIXING IS EXPECTED BUT COULD SEE SOME SHALLOWING FOR MORE
OF THE HIGHER TERRAIN AREAS GETTING INTO THE CLOUD LAYER FOR FOG
OR GETTING ABOVE IT FOR CLEARING. SHORTWAVE MOVING TOWARD THE
REGION TONIGHT COULD RESULT IN ENOUGH TURBULENCE TO MIX OUT THE
LOW LEVEL MOISTURE.

SHORTWAVE DOES BRING TO ELEVATED MOISTURE AND LIFT ALONG A FRONTAL
BOUNDARY ON WEDNESDAY FOR A FEW SNOW SHOWERS. WESTERLY FLOW BEHIND
THE WAVE SHOULD RESULT IN SLIGHTLY WARMER TEMPERATURES IN THE
SOUTHWEST ZONES. EBERT


.LONG TERM...THURSDAY NIGHT THROUGH TUESDAY...

SYNOPTIC SET UP... WITH WEAK POOLED COLD AIR AT THE SURFACE OVER
THE EASTERN GREAT PLAINS. A RIDGE RUNS UP THE COAST FROM
CALIFORNIA TO SOUTHERN BRITISH COLUMBIA. NORTHEAST MONTANA LIES
BETWEEN THESE TWO FEATURES IN A UNENERGETIC WEAK NORTHWESTERN FLOW.
COLDEST AIR OF THE NORTHERN HEMISPHERE LIES BOTTLED UP OVER THE
ARCTIC.

THURSDAY NIGHT THROUGH SUNDAY... RIDGE TO THE WEST GAINS
INCREASING INFLUENCE AND PLACES NORTHEAST MONTANA UNDER PARTLY
CLOUDY AND DRY CONDITIONS DUE TO A STABLE ATMOSPHERE. SUBTLE
SHORTWAVES APPEAR IN THE FLOW... ESPECIALLY ON SATURDAY... BUT
REMAIN RELATIVELY UN-ENERGIZED AND SEEM INSUFFICIENT TO CAUSE
PRECIPITATION AT THIS TIME.

SUNDAY NIGHT ONWARD... WESTERN RIDGE WILL FINALLY MOVE THROUGH
THE AREA AND GENERATE CONDITIONS FOR A PREFRONTAL WARMING SPIKE
ON SUNDAY NIGHT. BY MONDAY AN ARCTIC INTRUSION IS ANTICIPATED TO
BEGIN AND WILL BRING A COLD FRONT THROUGH THE REGION. POSSIBLE
PACIFIC MOISTURE AT THE CREST OF THE EXITING RIDGE COULD HELP TO
GENERATE SHOWER STARTING DURING THIS PERIOD AND LASTING THROUGH
TUESDAY. AFTERWARD TEMPERATURES ARE EXPECTED TO BEGIN DROPPING
OFF.

GAH

&&

.AVIATION...

FLIGHT CATEGORY: MVFR

SYNOPSIS: TERMINALS WILL CONTINUE TO BE SOCKED IN BY WIDESPREAD LOW
LEVEL STRATUS. FUEL LOADING IS LIKELY FOR MOST SITES. SMALL
BREAKS IN THE STRATUS MAY BEGIN TO APPEAR  THIS AFTERNOON...
BUT FULL CLEARING MAY NOT OCCUR UNTIL MID WEEK.

AREA WINDS: LIGHT AND VARIABLE OVERNIGHT... BECOMING SOUTHEAST
AROUND 5 TO 10 KTS BY THE LATE MORNING.

GAH


&&

.GLASGOW WATCHES/WARNINGS/ADVISORIES...NONE.

&&

$$

WEATHER.GOV/GLASGOW






000
FXUS65 KMSO 161041
AFDMSO

Area Forecast Discussion
National Weather Service Missoula MT
341 AM MST TUE DEC 16 2014

.DISCUSSION...A weak disturbance moving in from the southwest has
produced a few light snow showers over north-central Idaho
overnight and this morning, and is currently moving into western
Montana. Showers have generally been light in nature, though
webcams are showing a light coating on the roadway over Greer
Grade in Idaho and over Lost Trail Pass. So the morning commute
could be a little slick in spots. Most of what is falling in
western Montana is mainly flurries.

Another surge of light snow will move over Lemhi county and
southwestern Montana later today into Wednesday morning. Again,
the snow will be light and only up to an inch is possible in the
higher terrain like Gilmore Summit in Idaho, Georgetown Lake and
Philipsburg in Montana. A brief ridge of high pressure will build
over the region Wednesday that will help dry things out.
Temperatures will be around normal for most locations (upper 20s-low
30s).

a very weak disturbance will swing through the region on Wednesday
night into Thursday causing light widespread precipitation. The
best chance for moisture will be across northwest Montana. The
valleys could see up to an inch of snow accumulations while the
higher terrain could receive a couple of inches. A ridge quickly
moves through the region on Friday causing a drying trend to the
Northern Rockies. This ridge will be short lived as another
feature swings through the area Friday into Friday night. This
feature will be slightly more substantial than the previous
disturbance, but precipitation is still anticipated to be fairly
light and have minimal impacts to the area.

The models continue to trend to a very moist and fairly warm plume
of moisture starting to stream into the region Sunday through
Monday. Snow levels will be steadily climbing during the period
with the potential of snow be above area mountain passes by Sunday
afternoon. The area could receive significant precipitation from
this event. The upper level flow will transition to the northwest
causing snow levels to start dropping by Tuesday, but the bulk of
the moisture will be out of our region.


&&

.AVIATION...Breezy conditions overnight and this morning has kept
the formation of fog at bay for most locations around
area air terminals. Due to the breeze drying out the low-levels,
fog is not expected to form this morning. Otherwise a few mid-
levels clouds today may occasionally obscure the higher terrain.


&&

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

$$




000
FXUS65 KMSO 161041
AFDMSO

Area Forecast Discussion
National Weather Service Missoula MT
341 AM MST TUE DEC 16 2014

.DISCUSSION...A weak disturbance moving in from the southwest has
produced a few light snow showers over north-central Idaho
overnight and this morning, and is currently moving into western
Montana. Showers have generally been light in nature, though
webcams are showing a light coating on the roadway over Greer
Grade in Idaho and over Lost Trail Pass. So the morning commute
could be a little slick in spots. Most of what is falling in
western Montana is mainly flurries.

Another surge of light snow will move over Lemhi county and
southwestern Montana later today into Wednesday morning. Again,
the snow will be light and only up to an inch is possible in the
higher terrain like Gilmore Summit in Idaho, Georgetown Lake and
Philipsburg in Montana. A brief ridge of high pressure will build
over the region Wednesday that will help dry things out.
Temperatures will be around normal for most locations (upper 20s-low
30s).

a very weak disturbance will swing through the region on Wednesday
night into Thursday causing light widespread precipitation. The
best chance for moisture will be across northwest Montana. The
valleys could see up to an inch of snow accumulations while the
higher terrain could receive a couple of inches. A ridge quickly
moves through the region on Friday causing a drying trend to the
Northern Rockies. This ridge will be short lived as another
feature swings through the area Friday into Friday night. This
feature will be slightly more substantial than the previous
disturbance, but precipitation is still anticipated to be fairly
light and have minimal impacts to the area.

The models continue to trend to a very moist and fairly warm plume
of moisture starting to stream into the region Sunday through
Monday. Snow levels will be steadily climbing during the period
with the potential of snow be above area mountain passes by Sunday
afternoon. The area could receive significant precipitation from
this event. The upper level flow will transition to the northwest
causing snow levels to start dropping by Tuesday, but the bulk of
the moisture will be out of our region.


&&

.AVIATION...Breezy conditions overnight and this morning has kept
the formation of fog at bay for most locations around
area air terminals. Due to the breeze drying out the low-levels,
fog is not expected to form this morning. Otherwise a few mid-
levels clouds today may occasionally obscure the higher terrain.


&&

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

$$





000
FXUS65 KBYZ 161038
AFDBYZ

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BILLINGS MT
338 AM MST TUE DEC 16 2014

.SHORT TERM...VALID FOR TDY AND WED...

MAIN FORECAST PROBLEM FOR THE SHORT TERM CONCERNS CONSIDERABLE
AREAS OF FOG ACROSS THE FORECAST AREA...PARTICULARLY IN THE
LOWER ELEVATIONS OF THE WESTERN ZONES. THE PATTERN FAVORS THIS TO
CONTINUE WITH A RIDGE ALOFT AND SURFACE LOW PRESSURE TO OUR
WEST/SOUTHWEST THUS KEEPING A SOUTHEAST LOW LEVEL FLOW UPSLOPING
INTO SOUTH CENTRAL MONTANA. LOCAL OBSERVATIONS SHOW A QUARTER MILE
VISIBILITY OR LESS IN AREAS JUST WEST OF BILLINGS TO LIVINGSTON
AND UP TO JUDITH GAP. MESOSCALE CROSS SECTIONS SHOW THIS
PERSISTING THROUGH MUCH OF THE MORNING FOR THIS AREA...AND PERHAPS
EVEN INTO THE AFTERNOON FOR PARK COUNTY AROUND LIVINGSTON. THIS
WILL ALSO TEND TO PREVENT MUCH IF ANY SOLAR RADIATION FOR MUCH OF
THE DAY AND SINCE MOS GUIDANCE IS NOT TAKING IT INTO ACCOUNT I
WILL BE SURE TO UNDERCUT GUIDANCE IN THESE AREAS. MAIN
MESSAGE...FOGGY AND CONTINUED CHILLY MOST LOCATIONS TODAY.

DENSE FOG ADVISORY...ISSUED ACROSS AREAS GENERALLY FROM LIVINGSTON
TO BIG TIMBER AND UP TO JUDITH GAP WHERE OBSERVATIONS INDICATE
PERSISTENT DENSE FOG. LOCALLY ICY ROADS WILL MAKE THIS EVEN MORE
DANGEROUS. AS MENTIONED BEFORE PROGGS SUGGEST THE WIDESPREAD FOG
WILL LINGER IN THESE AREAS UNTIL ABOUT 18Z.

IN THE MEANTIME...THE 500MB RIDGE BUILDING OVER US NOW WILL
QUICKLY BREAK DOWN LATE TODAY AND TONIGHT AS ANOTHER BROAD SPLIT
FLOW TROUGH MOVES INTO THE WESTERN UNITED STATES. A WEAKER SHORT
WAVE IN THE MEAN FLOW WILL SPLIT FROM THE SOUTHERN BRANCH AND
TRACK OVER OUR REGION TONIGHT AND INTO WEDNESDAY. QPF PROGGS ARE
NOT IMPRESSIVE BUT SEEMS PRUDENT TO BUMP UP SOME OF THE POPS NOW
FOR THE HIGH COUNTRY. WE MAY SEE SOME FLURRIES OR LIGHT SNOW IN
THE EAST AS IT MOVES THROUGH WEDNESDAY MORNING AS WELL. LOOK FOR A
MODEST WARM UP TO AROUND SEASONAL AVERAGES FOR WEDNESDAY. BT


.LONG TERM...VALID FOR THU...FRI...SAT...SUN...MON...

ENSEMBLE FORECASTS FROM THE GFS AND ECMWF WERE SHOWING MORE
CONFIDENCE IN THEIR SOLUTIONS FOR THE EXTENDED PERIOD THAN THEY
HAVE IN PREVIOUS RUNS.

FLOW GENERALLY BECOMES MORE PROGRESSIVE WITH TIME. WEAK NORTHERN
STREAM OF A PACIFIC TROUGH WILL BE OVER THE REGION ON THU. THIS
WILL BE FOLLOWED BY A SHORTWAVE RIDGE ON FRI AND ANOTHER WEAK
TROUGH FOR SAT. WENT WITH SUPER BLEND POPS FOR THIS PERIOD WHERE
MOISTURE AFFECTS MAINLY THE MOUNTAINS. A STRONG PACIFIC JET WILL
MOVE INTO THE REGION LATE IN THE PERIOD WHICH RESULTS IN A FAST
WNW FLOW OVERTAKING THE AREA BEGINNING ON SUN. ENERGY WILL MOVE
THROUGH THIS FLOW ALONG WITH PERIODS OF PACIFIC MOISTURE. GEFS
SHOWED AN ATMOSPHERIC RIVER WILL AFFECT THE REGION SUN INTO MON
WHICH WILL CONTRIBUTE TO PRECIPITATION CHANCES. HAVE INCREASED
POPS OVER THE AREA BEGINNING ON SUN. MAY HAVE GAP WIND ISSUES SAT
NIGHT INTO MON AS MODELS AGREED ON STRONG LEE TROUGHING OVER THE
AREA. WILL CONTINUE TO HAVE STRONG WINDS IN THE FORECAST FOR THE
GAP AREAS. THE MODELS WERE IN GOOD AGREEMENT WITH TEMPERATURES
THROUGH THE EXTENDED AND SHOWED ABOVE NORMAL READINGS. ARTHUR
&&

.AVIATION...

LIFR TO VLIFR CONDITIONS IN STRATUS AND FOG WILL PERSIST FROM
ROSEBUD COUNTY W THROUGH MID-MORNING...THEN CONDITIONS WILL
IMPROVE TO MVFR/VFR. E OF ROSEBUD COUNTY...EXPECT MVFR/IFR
CONDITIONS WITH LITTLE IMPROVEMENT THROUGH THE DAY. MVFR TO IFR
CONDITIONS ARE EXPECTED TONIGHT ACROSS THE AREA WITH LOWER
CONDITIONS POSSIBLE. MOUNTAIN OBSCURATIONS WILL BE WIDESPREAD
THROUGH TONIGHT. ARTHUR
&&

.PRELIMINARY POINT TEMP/POPS...

    TDY WED     THU     FRI     SAT     SUN     MON
-------------------------------------------------------
BIL 027 020/036 022/039 023/039 026/042 025/043 035/045
    0/E 11/B    01/B    10/U    11/B    12/W    23/W
LVM 034 024/042 023/042 022/041 026/043 026/043 033/045
    1/F 22/J    11/E    11/U    11/B    13/W    33/W
HDN 029 014/033 015/037 017/038 019/040 019/041 028/043
    0/E 01/B    01/B    10/U    01/B    11/B    23/W
MLS 027 015/030 017/036 019/037 018/038 022/039 028/042
    0/E 01/B    01/B    10/U    01/U    11/U    23/W
4BQ 030 015/033 016/040 018/040 016/041 020/042 027/043
    0/E 02/J    01/B    10/U    01/U    11/B    23/W
BHK 024 012/028 015/035 019/037 016/038 020/039 025/041
    0/E 02/J    11/B    11/U    01/U    11/B    23/W
SHR 030 015/036 016/038 016/038 019/040 019/041 026/042
    0/E 01/B    01/B    10/U    01/B    12/J    33/W

&&

.BYZ WATCHES/WARNINGS/ADVISORIES...
MT...DENSE FOG ADVISORY IN EFFECT UNTIL 11 AM MST THIS MORNING FOR
      ZONES 28-34-40-41-63-65.
WY...NONE.

&&

$$
WEATHER.GOV/BILLINGS



000
FXUS65 KBYZ 161038
AFDBYZ

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BILLINGS MT
338 AM MST TUE DEC 16 2014

.SHORT TERM...VALID FOR TDY AND WED...

MAIN FORECAST PROBLEM FOR THE SHORT TERM CONCERNS CONSIDERABLE
AREAS OF FOG ACROSS THE FORECAST AREA...PARTICULARLY IN THE
LOWER ELEVATIONS OF THE WESTERN ZONES. THE PATTERN FAVORS THIS TO
CONTINUE WITH A RIDGE ALOFT AND SURFACE LOW PRESSURE TO OUR
WEST/SOUTHWEST THUS KEEPING A SOUTHEAST LOW LEVEL FLOW UPSLOPING
INTO SOUTH CENTRAL MONTANA. LOCAL OBSERVATIONS SHOW A QUARTER MILE
VISIBILITY OR LESS IN AREAS JUST WEST OF BILLINGS TO LIVINGSTON
AND UP TO JUDITH GAP. MESOSCALE CROSS SECTIONS SHOW THIS
PERSISTING THROUGH MUCH OF THE MORNING FOR THIS AREA...AND PERHAPS
EVEN INTO THE AFTERNOON FOR PARK COUNTY AROUND LIVINGSTON. THIS
WILL ALSO TEND TO PREVENT MUCH IF ANY SOLAR RADIATION FOR MUCH OF
THE DAY AND SINCE MOS GUIDANCE IS NOT TAKING IT INTO ACCOUNT I
WILL BE SURE TO UNDERCUT GUIDANCE IN THESE AREAS. MAIN
MESSAGE...FOGGY AND CONTINUED CHILLY MOST LOCATIONS TODAY.

DENSE FOG ADVISORY...ISSUED ACROSS AREAS GENERALLY FROM LIVINGSTON
TO BIG TIMBER AND UP TO JUDITH GAP WHERE OBSERVATIONS INDICATE
PERSISTENT DENSE FOG. LOCALLY ICY ROADS WILL MAKE THIS EVEN MORE
DANGEROUS. AS MENTIONED BEFORE PROGGS SUGGEST THE WIDESPREAD FOG
WILL LINGER IN THESE AREAS UNTIL ABOUT 18Z.

IN THE MEANTIME...THE 500MB RIDGE BUILDING OVER US NOW WILL
QUICKLY BREAK DOWN LATE TODAY AND TONIGHT AS ANOTHER BROAD SPLIT
FLOW TROUGH MOVES INTO THE WESTERN UNITED STATES. A WEAKER SHORT
WAVE IN THE MEAN FLOW WILL SPLIT FROM THE SOUTHERN BRANCH AND
TRACK OVER OUR REGION TONIGHT AND INTO WEDNESDAY. QPF PROGGS ARE
NOT IMPRESSIVE BUT SEEMS PRUDENT TO BUMP UP SOME OF THE POPS NOW
FOR THE HIGH COUNTRY. WE MAY SEE SOME FLURRIES OR LIGHT SNOW IN
THE EAST AS IT MOVES THROUGH WEDNESDAY MORNING AS WELL. LOOK FOR A
MODEST WARM UP TO AROUND SEASONAL AVERAGES FOR WEDNESDAY. BT


.LONG TERM...VALID FOR THU...FRI...SAT...SUN...MON...

ENSEMBLE FORECASTS FROM THE GFS AND ECMWF WERE SHOWING MORE
CONFIDENCE IN THEIR SOLUTIONS FOR THE EXTENDED PERIOD THAN THEY
HAVE IN PREVIOUS RUNS.

FLOW GENERALLY BECOMES MORE PROGRESSIVE WITH TIME. WEAK NORTHERN
STREAM OF A PACIFIC TROUGH WILL BE OVER THE REGION ON THU. THIS
WILL BE FOLLOWED BY A SHORTWAVE RIDGE ON FRI AND ANOTHER WEAK
TROUGH FOR SAT. WENT WITH SUPER BLEND POPS FOR THIS PERIOD WHERE
MOISTURE AFFECTS MAINLY THE MOUNTAINS. A STRONG PACIFIC JET WILL
MOVE INTO THE REGION LATE IN THE PERIOD WHICH RESULTS IN A FAST
WNW FLOW OVERTAKING THE AREA BEGINNING ON SUN. ENERGY WILL MOVE
THROUGH THIS FLOW ALONG WITH PERIODS OF PACIFIC MOISTURE. GEFS
SHOWED AN ATMOSPHERIC RIVER WILL AFFECT THE REGION SUN INTO MON
WHICH WILL CONTRIBUTE TO PRECIPITATION CHANCES. HAVE INCREASED
POPS OVER THE AREA BEGINNING ON SUN. MAY HAVE GAP WIND ISSUES SAT
NIGHT INTO MON AS MODELS AGREED ON STRONG LEE TROUGHING OVER THE
AREA. WILL CONTINUE TO HAVE STRONG WINDS IN THE FORECAST FOR THE
GAP AREAS. THE MODELS WERE IN GOOD AGREEMENT WITH TEMPERATURES
THROUGH THE EXTENDED AND SHOWED ABOVE NORMAL READINGS. ARTHUR
&&

.AVIATION...

LIFR TO VLIFR CONDITIONS IN STRATUS AND FOG WILL PERSIST FROM
ROSEBUD COUNTY W THROUGH MID-MORNING...THEN CONDITIONS WILL
IMPROVE TO MVFR/VFR. E OF ROSEBUD COUNTY...EXPECT MVFR/IFR
CONDITIONS WITH LITTLE IMPROVEMENT THROUGH THE DAY. MVFR TO IFR
CONDITIONS ARE EXPECTED TONIGHT ACROSS THE AREA WITH LOWER
CONDITIONS POSSIBLE. MOUNTAIN OBSCURATIONS WILL BE WIDESPREAD
THROUGH TONIGHT. ARTHUR
&&

.PRELIMINARY POINT TEMP/POPS...

    TDY WED     THU     FRI     SAT     SUN     MON
-------------------------------------------------------
BIL 027 020/036 022/039 023/039 026/042 025/043 035/045
    0/E 11/B    01/B    10/U    11/B    12/W    23/W
LVM 034 024/042 023/042 022/041 026/043 026/043 033/045
    1/F 22/J    11/E    11/U    11/B    13/W    33/W
HDN 029 014/033 015/037 017/038 019/040 019/041 028/043
    0/E 01/B    01/B    10/U    01/B    11/B    23/W
MLS 027 015/030 017/036 019/037 018/038 022/039 028/042
    0/E 01/B    01/B    10/U    01/U    11/U    23/W
4BQ 030 015/033 016/040 018/040 016/041 020/042 027/043
    0/E 02/J    01/B    10/U    01/U    11/B    23/W
BHK 024 012/028 015/035 019/037 016/038 020/039 025/041
    0/E 02/J    11/B    11/U    01/U    11/B    23/W
SHR 030 015/036 016/038 016/038 019/040 019/041 026/042
    0/E 01/B    01/B    10/U    01/B    12/J    33/W

&&

.BYZ WATCHES/WARNINGS/ADVISORIES...
MT...DENSE FOG ADVISORY IN EFFECT UNTIL 11 AM MST THIS MORNING FOR
      ZONES 28-34-40-41-63-65.
WY...NONE.

&&

$$
WEATHER.GOV/BILLINGS



000
FXUS65 KBYZ 161038
AFDBYZ

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BILLINGS MT
338 AM MST TUE DEC 16 2014

.SHORT TERM...VALID FOR TDY AND WED...

MAIN FORECAST PROBLEM FOR THE SHORT TERM CONCERNS CONSIDERABLE
AREAS OF FOG ACROSS THE FORECAST AREA...PARTICULARLY IN THE
LOWER ELEVATIONS OF THE WESTERN ZONES. THE PATTERN FAVORS THIS TO
CONTINUE WITH A RIDGE ALOFT AND SURFACE LOW PRESSURE TO OUR
WEST/SOUTHWEST THUS KEEPING A SOUTHEAST LOW LEVEL FLOW UPSLOPING
INTO SOUTH CENTRAL MONTANA. LOCAL OBSERVATIONS SHOW A QUARTER MILE
VISIBILITY OR LESS IN AREAS JUST WEST OF BILLINGS TO LIVINGSTON
AND UP TO JUDITH GAP. MESOSCALE CROSS SECTIONS SHOW THIS
PERSISTING THROUGH MUCH OF THE MORNING FOR THIS AREA...AND PERHAPS
EVEN INTO THE AFTERNOON FOR PARK COUNTY AROUND LIVINGSTON. THIS
WILL ALSO TEND TO PREVENT MUCH IF ANY SOLAR RADIATION FOR MUCH OF
THE DAY AND SINCE MOS GUIDANCE IS NOT TAKING IT INTO ACCOUNT I
WILL BE SURE TO UNDERCUT GUIDANCE IN THESE AREAS. MAIN
MESSAGE...FOGGY AND CONTINUED CHILLY MOST LOCATIONS TODAY.

DENSE FOG ADVISORY...ISSUED ACROSS AREAS GENERALLY FROM LIVINGSTON
TO BIG TIMBER AND UP TO JUDITH GAP WHERE OBSERVATIONS INDICATE
PERSISTENT DENSE FOG. LOCALLY ICY ROADS WILL MAKE THIS EVEN MORE
DANGEROUS. AS MENTIONED BEFORE PROGGS SUGGEST THE WIDESPREAD FOG
WILL LINGER IN THESE AREAS UNTIL ABOUT 18Z.

IN THE MEANTIME...THE 500MB RIDGE BUILDING OVER US NOW WILL
QUICKLY BREAK DOWN LATE TODAY AND TONIGHT AS ANOTHER BROAD SPLIT
FLOW TROUGH MOVES INTO THE WESTERN UNITED STATES. A WEAKER SHORT
WAVE IN THE MEAN FLOW WILL SPLIT FROM THE SOUTHERN BRANCH AND
TRACK OVER OUR REGION TONIGHT AND INTO WEDNESDAY. QPF PROGGS ARE
NOT IMPRESSIVE BUT SEEMS PRUDENT TO BUMP UP SOME OF THE POPS NOW
FOR THE HIGH COUNTRY. WE MAY SEE SOME FLURRIES OR LIGHT SNOW IN
THE EAST AS IT MOVES THROUGH WEDNESDAY MORNING AS WELL. LOOK FOR A
MODEST WARM UP TO AROUND SEASONAL AVERAGES FOR WEDNESDAY. BT


.LONG TERM...VALID FOR THU...FRI...SAT...SUN...MON...

ENSEMBLE FORECASTS FROM THE GFS AND ECMWF WERE SHOWING MORE
CONFIDENCE IN THEIR SOLUTIONS FOR THE EXTENDED PERIOD THAN THEY
HAVE IN PREVIOUS RUNS.

FLOW GENERALLY BECOMES MORE PROGRESSIVE WITH TIME. WEAK NORTHERN
STREAM OF A PACIFIC TROUGH WILL BE OVER THE REGION ON THU. THIS
WILL BE FOLLOWED BY A SHORTWAVE RIDGE ON FRI AND ANOTHER WEAK
TROUGH FOR SAT. WENT WITH SUPER BLEND POPS FOR THIS PERIOD WHERE
MOISTURE AFFECTS MAINLY THE MOUNTAINS. A STRONG PACIFIC JET WILL
MOVE INTO THE REGION LATE IN THE PERIOD WHICH RESULTS IN A FAST
WNW FLOW OVERTAKING THE AREA BEGINNING ON SUN. ENERGY WILL MOVE
THROUGH THIS FLOW ALONG WITH PERIODS OF PACIFIC MOISTURE. GEFS
SHOWED AN ATMOSPHERIC RIVER WILL AFFECT THE REGION SUN INTO MON
WHICH WILL CONTRIBUTE TO PRECIPITATION CHANCES. HAVE INCREASED
POPS OVER THE AREA BEGINNING ON SUN. MAY HAVE GAP WIND ISSUES SAT
NIGHT INTO MON AS MODELS AGREED ON STRONG LEE TROUGHING OVER THE
AREA. WILL CONTINUE TO HAVE STRONG WINDS IN THE FORECAST FOR THE
GAP AREAS. THE MODELS WERE IN GOOD AGREEMENT WITH TEMPERATURES
THROUGH THE EXTENDED AND SHOWED ABOVE NORMAL READINGS. ARTHUR
&&

.AVIATION...

LIFR TO VLIFR CONDITIONS IN STRATUS AND FOG WILL PERSIST FROM
ROSEBUD COUNTY W THROUGH MID-MORNING...THEN CONDITIONS WILL
IMPROVE TO MVFR/VFR. E OF ROSEBUD COUNTY...EXPECT MVFR/IFR
CONDITIONS WITH LITTLE IMPROVEMENT THROUGH THE DAY. MVFR TO IFR
CONDITIONS ARE EXPECTED TONIGHT ACROSS THE AREA WITH LOWER
CONDITIONS POSSIBLE. MOUNTAIN OBSCURATIONS WILL BE WIDESPREAD
THROUGH TONIGHT. ARTHUR
&&

.PRELIMINARY POINT TEMP/POPS...

    TDY WED     THU     FRI     SAT     SUN     MON
-------------------------------------------------------
BIL 027 020/036 022/039 023/039 026/042 025/043 035/045
    0/E 11/B    01/B    10/U    11/B    12/W    23/W
LVM 034 024/042 023/042 022/041 026/043 026/043 033/045
    1/F 22/J    11/E    11/U    11/B    13/W    33/W
HDN 029 014/033 015/037 017/038 019/040 019/041 028/043
    0/E 01/B    01/B    10/U    01/B    11/B    23/W
MLS 027 015/030 017/036 019/037 018/038 022/039 028/042
    0/E 01/B    01/B    10/U    01/U    11/U    23/W
4BQ 030 015/033 016/040 018/040 016/041 020/042 027/043
    0/E 02/J    01/B    10/U    01/U    11/B    23/W
BHK 024 012/028 015/035 019/037 016/038 020/039 025/041
    0/E 02/J    11/B    11/U    01/U    11/B    23/W
SHR 030 015/036 016/038 016/038 019/040 019/041 026/042
    0/E 01/B    01/B    10/U    01/B    12/J    33/W

&&

.BYZ WATCHES/WARNINGS/ADVISORIES...
MT...DENSE FOG ADVISORY IN EFFECT UNTIL 11 AM MST THIS MORNING FOR
      ZONES 28-34-40-41-63-65.
WY...NONE.

&&

$$
WEATHER.GOV/BILLINGS



000
FXUS65 KBYZ 161038
AFDBYZ

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BILLINGS MT
338 AM MST TUE DEC 16 2014

.SHORT TERM...VALID FOR TDY AND WED...

MAIN FORECAST PROBLEM FOR THE SHORT TERM CONCERNS CONSIDERABLE
AREAS OF FOG ACROSS THE FORECAST AREA...PARTICULARLY IN THE
LOWER ELEVATIONS OF THE WESTERN ZONES. THE PATTERN FAVORS THIS TO
CONTINUE WITH A RIDGE ALOFT AND SURFACE LOW PRESSURE TO OUR
WEST/SOUTHWEST THUS KEEPING A SOUTHEAST LOW LEVEL FLOW UPSLOPING
INTO SOUTH CENTRAL MONTANA. LOCAL OBSERVATIONS SHOW A QUARTER MILE
VISIBILITY OR LESS IN AREAS JUST WEST OF BILLINGS TO LIVINGSTON
AND UP TO JUDITH GAP. MESOSCALE CROSS SECTIONS SHOW THIS
PERSISTING THROUGH MUCH OF THE MORNING FOR THIS AREA...AND PERHAPS
EVEN INTO THE AFTERNOON FOR PARK COUNTY AROUND LIVINGSTON. THIS
WILL ALSO TEND TO PREVENT MUCH IF ANY SOLAR RADIATION FOR MUCH OF
THE DAY AND SINCE MOS GUIDANCE IS NOT TAKING IT INTO ACCOUNT I
WILL BE SURE TO UNDERCUT GUIDANCE IN THESE AREAS. MAIN
MESSAGE...FOGGY AND CONTINUED CHILLY MOST LOCATIONS TODAY.

DENSE FOG ADVISORY...ISSUED ACROSS AREAS GENERALLY FROM LIVINGSTON
TO BIG TIMBER AND UP TO JUDITH GAP WHERE OBSERVATIONS INDICATE
PERSISTENT DENSE FOG. LOCALLY ICY ROADS WILL MAKE THIS EVEN MORE
DANGEROUS. AS MENTIONED BEFORE PROGGS SUGGEST THE WIDESPREAD FOG
WILL LINGER IN THESE AREAS UNTIL ABOUT 18Z.

IN THE MEANTIME...THE 500MB RIDGE BUILDING OVER US NOW WILL
QUICKLY BREAK DOWN LATE TODAY AND TONIGHT AS ANOTHER BROAD SPLIT
FLOW TROUGH MOVES INTO THE WESTERN UNITED STATES. A WEAKER SHORT
WAVE IN THE MEAN FLOW WILL SPLIT FROM THE SOUTHERN BRANCH AND
TRACK OVER OUR REGION TONIGHT AND INTO WEDNESDAY. QPF PROGGS ARE
NOT IMPRESSIVE BUT SEEMS PRUDENT TO BUMP UP SOME OF THE POPS NOW
FOR THE HIGH COUNTRY. WE MAY SEE SOME FLURRIES OR LIGHT SNOW IN
THE EAST AS IT MOVES THROUGH WEDNESDAY MORNING AS WELL. LOOK FOR A
MODEST WARM UP TO AROUND SEASONAL AVERAGES FOR WEDNESDAY. BT


.LONG TERM...VALID FOR THU...FRI...SAT...SUN...MON...

ENSEMBLE FORECASTS FROM THE GFS AND ECMWF WERE SHOWING MORE
CONFIDENCE IN THEIR SOLUTIONS FOR THE EXTENDED PERIOD THAN THEY
HAVE IN PREVIOUS RUNS.

FLOW GENERALLY BECOMES MORE PROGRESSIVE WITH TIME. WEAK NORTHERN
STREAM OF A PACIFIC TROUGH WILL BE OVER THE REGION ON THU. THIS
WILL BE FOLLOWED BY A SHORTWAVE RIDGE ON FRI AND ANOTHER WEAK
TROUGH FOR SAT. WENT WITH SUPER BLEND POPS FOR THIS PERIOD WHERE
MOISTURE AFFECTS MAINLY THE MOUNTAINS. A STRONG PACIFIC JET WILL
MOVE INTO THE REGION LATE IN THE PERIOD WHICH RESULTS IN A FAST
WNW FLOW OVERTAKING THE AREA BEGINNING ON SUN. ENERGY WILL MOVE
THROUGH THIS FLOW ALONG WITH PERIODS OF PACIFIC MOISTURE. GEFS
SHOWED AN ATMOSPHERIC RIVER WILL AFFECT THE REGION SUN INTO MON
WHICH WILL CONTRIBUTE TO PRECIPITATION CHANCES. HAVE INCREASED
POPS OVER THE AREA BEGINNING ON SUN. MAY HAVE GAP WIND ISSUES SAT
NIGHT INTO MON AS MODELS AGREED ON STRONG LEE TROUGHING OVER THE
AREA. WILL CONTINUE TO HAVE STRONG WINDS IN THE FORECAST FOR THE
GAP AREAS. THE MODELS WERE IN GOOD AGREEMENT WITH TEMPERATURES
THROUGH THE EXTENDED AND SHOWED ABOVE NORMAL READINGS. ARTHUR
&&

.AVIATION...

LIFR TO VLIFR CONDITIONS IN STRATUS AND FOG WILL PERSIST FROM
ROSEBUD COUNTY W THROUGH MID-MORNING...THEN CONDITIONS WILL
IMPROVE TO MVFR/VFR. E OF ROSEBUD COUNTY...EXPECT MVFR/IFR
CONDITIONS WITH LITTLE IMPROVEMENT THROUGH THE DAY. MVFR TO IFR
CONDITIONS ARE EXPECTED TONIGHT ACROSS THE AREA WITH LOWER
CONDITIONS POSSIBLE. MOUNTAIN OBSCURATIONS WILL BE WIDESPREAD
THROUGH TONIGHT. ARTHUR
&&

.PRELIMINARY POINT TEMP/POPS...

    TDY WED     THU     FRI     SAT     SUN     MON
-------------------------------------------------------
BIL 027 020/036 022/039 023/039 026/042 025/043 035/045
    0/E 11/B    01/B    10/U    11/B    12/W    23/W
LVM 034 024/042 023/042 022/041 026/043 026/043 033/045
    1/F 22/J    11/E    11/U    11/B    13/W    33/W
HDN 029 014/033 015/037 017/038 019/040 019/041 028/043
    0/E 01/B    01/B    10/U    01/B    11/B    23/W
MLS 027 015/030 017/036 019/037 018/038 022/039 028/042
    0/E 01/B    01/B    10/U    01/U    11/U    23/W
4BQ 030 015/033 016/040 018/040 016/041 020/042 027/043
    0/E 02/J    01/B    10/U    01/U    11/B    23/W
BHK 024 012/028 015/035 019/037 016/038 020/039 025/041
    0/E 02/J    11/B    11/U    01/U    11/B    23/W
SHR 030 015/036 016/038 016/038 019/040 019/041 026/042
    0/E 01/B    01/B    10/U    01/B    12/J    33/W

&&

.BYZ WATCHES/WARNINGS/ADVISORIES...
MT...DENSE FOG ADVISORY IN EFFECT UNTIL 11 AM MST THIS MORNING FOR
      ZONES 28-34-40-41-63-65.
WY...NONE.

&&

$$
WEATHER.GOV/BILLINGS



000
FXUS65 KTFX 161030
AFDTFX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREAT FALLS MT
330 AM MST Tue Dec 16 2014

.DISCUSSION...

Today through Thursday...Forecast for the short term period is
expected to remain foggy this morning. Have expanded the Freezing
Fog Advisory to include Cascade and Judith Basin Counties as well
as the Rocky Mountain based on latest observations and SPORT night
time microphysics RGB imagery. Shortwave energy is still on track
to push into southwest Montana today and then into central Montana
overnight. Have increased PoPs across portions of the forecast
area based upon NAM model run but do not anticipated that snowfall
will be widespread enough or heavy enough to require any type of
highlights. Temperatures will remain near or below seasonal
averages for this time of year but I have undercut office-derived
SuperBlend temperature guidance for today and Wednesday given poor
perfomance on Monday. Expect another lull in clouds and
precipitation Wednesday night into Thursday before the progressive
pattern aloft brings another shortwave into western portions of
the forecast area Thursday afternoon. mpj

Thursday Night through Tuesday...A weak upper level ridge of high
pressure will keep the forecast area mostly dry Thursday night and
Friday. A shortwave trough will then move into the area Friday night
into Saturday, bringing an increased chance of mountain snow.
However, breezy westerly downslope winds will keep the plains dry.
The weather pattern will change somewhat beginning on Sunday. An
upper level ridge of high pressure will strengthen off the
California coast and an upper level trough of low pressure will
deepen from Hudson Bay into the Great Lakes. This will put Montana
under the influence of a strong northwesterly flow aloft. The
strongest winds aloft (60 to 70 kt at 700 mb) will occur Sunday into
Monday with the passage of a disturbance embedded in the flow. This
set-up will bring gusty westerly downslope winds to much of the
area, but especially over the plains of north central Montana. In
fact, some areas along the Rocky Mountain Front could approach High
Wind criteria (40 mph sustained/58 mph gusts). Confidence is
increasing that High Wind highlights may be needed for this event.
There is also significant moisture with this disturbance, so have
increased the chance for precipitation out onto the plains. Although
the winds will decrease somewhat after the passage of the
disturbance, the northwesterly flow aloft will remain fairly moist,
so have kept the chance for precipitation above climatological
normals across the area into Tuesday. The breezy winds throughout
the period will keep temperatures around 10 degrees above normal.
The warmest day of the period appears to be Monday, when most lower
elevation locations should get well into the 40s.
Coulston

&&

.AVIATION...
UPDATED 0540Z.
Low clouds and dense fog will continue to affect portions of the
region over the next 24 hours. Cut Bank will see the greatest
impacts with widespread VLIFR conditions continuing through much of
the night. Patchy dense fog will be possible elsewhere...with
Bozeman and Great Falls being the 2nd best areas to see areas of
dense fog. Isolated snow showers will develop over far Southwest MT
mainly after 21z Tue...and spread northward into Central MT after
00z Wed. Brusda

&&

.PRELIMINARY POINT TEMPS/POPS...
GTF  28  22  36  24 /   0  20  30  10
CTB  25  17  34  21 /   0  10  10  10
HLN  30  20  32  19 /  10  30  20  10
BZN  29  19  33  15 /  10  30  20  10
WEY  29  18  31  14 /  40  50  40  20
DLN  31  21  34  19 /  20  30  10  10
HVR  26  15  30  20 /   0  10  20  10
LWT  30  22  37  21 /   0  20  20  10

&&

.TFX WATCHES/WARNINGS/ADVISORIES...
FREEZING FOG ADVISORY until 11 AM MST this morning Cascade...
Eastern Glacier...Eastern Pondera...Eastern Teton...Judith
Basin...Northern Rocky Mountain Front...Southern Rocky Mountain
Front...Toole.

&&

$$

weather.gov/greatfalls
www.twitter.com/NWSGreatFalls
www.facebook.com/NWSGreatFalls





000
FXUS65 KTFX 161030
AFDTFX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREAT FALLS MT
330 AM MST Tue Dec 16 2014

.DISCUSSION...

Today through Thursday...Forecast for the short term period is
expected to remain foggy this morning. Have expanded the Freezing
Fog Advisory to include Cascade and Judith Basin Counties as well
as the Rocky Mountain based on latest observations and SPORT night
time microphysics RGB imagery. Shortwave energy is still on track
to push into southwest Montana today and then into central Montana
overnight. Have increased PoPs across portions of the forecast
area based upon NAM model run but do not anticipated that snowfall
will be widespread enough or heavy enough to require any type of
highlights. Temperatures will remain near or below seasonal
averages for this time of year but I have undercut office-derived
SuperBlend temperature guidance for today and Wednesday given poor
perfomance on Monday. Expect another lull in clouds and
precipitation Wednesday night into Thursday before the progressive
pattern aloft brings another shortwave into western portions of
the forecast area Thursday afternoon. mpj

Thursday Night through Tuesday...A weak upper level ridge of high
pressure will keep the forecast area mostly dry Thursday night and
Friday. A shortwave trough will then move into the area Friday night
into Saturday, bringing an increased chance of mountain snow.
However, breezy westerly downslope winds will keep the plains dry.
The weather pattern will change somewhat beginning on Sunday. An
upper level ridge of high pressure will strengthen off the
California coast and an upper level trough of low pressure will
deepen from Hudson Bay into the Great Lakes. This will put Montana
under the influence of a strong northwesterly flow aloft. The
strongest winds aloft (60 to 70 kt at 700 mb) will occur Sunday into
Monday with the passage of a disturbance embedded in the flow. This
set-up will bring gusty westerly downslope winds to much of the
area, but especially over the plains of north central Montana. In
fact, some areas along the Rocky Mountain Front could approach High
Wind criteria (40 mph sustained/58 mph gusts). Confidence is
increasing that High Wind highlights may be needed for this event.
There is also significant moisture with this disturbance, so have
increased the chance for precipitation out onto the plains. Although
the winds will decrease somewhat after the passage of the
disturbance, the northwesterly flow aloft will remain fairly moist,
so have kept the chance for precipitation above climatological
normals across the area into Tuesday. The breezy winds throughout
the period will keep temperatures around 10 degrees above normal.
The warmest day of the period appears to be Monday, when most lower
elevation locations should get well into the 40s.
Coulston

&&

.AVIATION...
UPDATED 0540Z.
Low clouds and dense fog will continue to affect portions of the
region over the next 24 hours. Cut Bank will see the greatest
impacts with widespread VLIFR conditions continuing through much of
the night. Patchy dense fog will be possible elsewhere...with
Bozeman and Great Falls being the 2nd best areas to see areas of
dense fog. Isolated snow showers will develop over far Southwest MT
mainly after 21z Tue...and spread northward into Central MT after
00z Wed. Brusda

&&

.PRELIMINARY POINT TEMPS/POPS...
GTF  28  22  36  24 /   0  20  30  10
CTB  25  17  34  21 /   0  10  10  10
HLN  30  20  32  19 /  10  30  20  10
BZN  29  19  33  15 /  10  30  20  10
WEY  29  18  31  14 /  40  50  40  20
DLN  31  21  34  19 /  20  30  10  10
HVR  26  15  30  20 /   0  10  20  10
LWT  30  22  37  21 /   0  20  20  10

&&

.TFX WATCHES/WARNINGS/ADVISORIES...
FREEZING FOG ADVISORY until 11 AM MST this morning Cascade...
Eastern Glacier...Eastern Pondera...Eastern Teton...Judith
Basin...Northern Rocky Mountain Front...Southern Rocky Mountain
Front...Toole.

&&

$$

weather.gov/greatfalls
www.twitter.com/NWSGreatFalls
www.facebook.com/NWSGreatFalls





000
FXUS65 KTFX 161030
AFDTFX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREAT FALLS MT
330 AM MST Tue Dec 16 2014

.DISCUSSION...

Today through Thursday...Forecast for the short term period is
expected to remain foggy this morning. Have expanded the Freezing
Fog Advisory to include Cascade and Judith Basin Counties as well
as the Rocky Mountain based on latest observations and SPORT night
time microphysics RGB imagery. Shortwave energy is still on track
to push into southwest Montana today and then into central Montana
overnight. Have increased PoPs across portions of the forecast
area based upon NAM model run but do not anticipated that snowfall
will be widespread enough or heavy enough to require any type of
highlights. Temperatures will remain near or below seasonal
averages for this time of year but I have undercut office-derived
SuperBlend temperature guidance for today and Wednesday given poor
perfomance on Monday. Expect another lull in clouds and
precipitation Wednesday night into Thursday before the progressive
pattern aloft brings another shortwave into western portions of
the forecast area Thursday afternoon. mpj

Thursday Night through Tuesday...A weak upper level ridge of high
pressure will keep the forecast area mostly dry Thursday night and
Friday. A shortwave trough will then move into the area Friday night
into Saturday, bringing an increased chance of mountain snow.
However, breezy westerly downslope winds will keep the plains dry.
The weather pattern will change somewhat beginning on Sunday. An
upper level ridge of high pressure will strengthen off the
California coast and an upper level trough of low pressure will
deepen from Hudson Bay into the Great Lakes. This will put Montana
under the influence of a strong northwesterly flow aloft. The
strongest winds aloft (60 to 70 kt at 700 mb) will occur Sunday into
Monday with the passage of a disturbance embedded in the flow. This
set-up will bring gusty westerly downslope winds to much of the
area, but especially over the plains of north central Montana. In
fact, some areas along the Rocky Mountain Front could approach High
Wind criteria (40 mph sustained/58 mph gusts). Confidence is
increasing that High Wind highlights may be needed for this event.
There is also significant moisture with this disturbance, so have
increased the chance for precipitation out onto the plains. Although
the winds will decrease somewhat after the passage of the
disturbance, the northwesterly flow aloft will remain fairly moist,
so have kept the chance for precipitation above climatological
normals across the area into Tuesday. The breezy winds throughout
the period will keep temperatures around 10 degrees above normal.
The warmest day of the period appears to be Monday, when most lower
elevation locations should get well into the 40s.
Coulston

&&

.AVIATION...
UPDATED 0540Z.
Low clouds and dense fog will continue to affect portions of the
region over the next 24 hours. Cut Bank will see the greatest
impacts with widespread VLIFR conditions continuing through much of
the night. Patchy dense fog will be possible elsewhere...with
Bozeman and Great Falls being the 2nd best areas to see areas of
dense fog. Isolated snow showers will develop over far Southwest MT
mainly after 21z Tue...and spread northward into Central MT after
00z Wed. Brusda

&&

.PRELIMINARY POINT TEMPS/POPS...
GTF  28  22  36  24 /   0  20  30  10
CTB  25  17  34  21 /   0  10  10  10
HLN  30  20  32  19 /  10  30  20  10
BZN  29  19  33  15 /  10  30  20  10
WEY  29  18  31  14 /  40  50  40  20
DLN  31  21  34  19 /  20  30  10  10
HVR  26  15  30  20 /   0  10  20  10
LWT  30  22  37  21 /   0  20  20  10

&&

.TFX WATCHES/WARNINGS/ADVISORIES...
FREEZING FOG ADVISORY until 11 AM MST this morning Cascade...
Eastern Glacier...Eastern Pondera...Eastern Teton...Judith
Basin...Northern Rocky Mountain Front...Southern Rocky Mountain
Front...Toole.

&&

$$

weather.gov/greatfalls
www.twitter.com/NWSGreatFalls
www.facebook.com/NWSGreatFalls





000
FXUS65 KTFX 161030
AFDTFX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREAT FALLS MT
330 AM MST Tue Dec 16 2014

.DISCUSSION...

Today through Thursday...Forecast for the short term period is
expected to remain foggy this morning. Have expanded the Freezing
Fog Advisory to include Cascade and Judith Basin Counties as well
as the Rocky Mountain based on latest observations and SPORT night
time microphysics RGB imagery. Shortwave energy is still on track
to push into southwest Montana today and then into central Montana
overnight. Have increased PoPs across portions of the forecast
area based upon NAM model run but do not anticipated that snowfall
will be widespread enough or heavy enough to require any type of
highlights. Temperatures will remain near or below seasonal
averages for this time of year but I have undercut office-derived
SuperBlend temperature guidance for today and Wednesday given poor
perfomance on Monday. Expect another lull in clouds and
precipitation Wednesday night into Thursday before the progressive
pattern aloft brings another shortwave into western portions of
the forecast area Thursday afternoon. mpj

Thursday Night through Tuesday...A weak upper level ridge of high
pressure will keep the forecast area mostly dry Thursday night and
Friday. A shortwave trough will then move into the area Friday night
into Saturday, bringing an increased chance of mountain snow.
However, breezy westerly downslope winds will keep the plains dry.
The weather pattern will change somewhat beginning on Sunday. An
upper level ridge of high pressure will strengthen off the
California coast and an upper level trough of low pressure will
deepen from Hudson Bay into the Great Lakes. This will put Montana
under the influence of a strong northwesterly flow aloft. The
strongest winds aloft (60 to 70 kt at 700 mb) will occur Sunday into
Monday with the passage of a disturbance embedded in the flow. This
set-up will bring gusty westerly downslope winds to much of the
area, but especially over the plains of north central Montana. In
fact, some areas along the Rocky Mountain Front could approach High
Wind criteria (40 mph sustained/58 mph gusts). Confidence is
increasing that High Wind highlights may be needed for this event.
There is also significant moisture with this disturbance, so have
increased the chance for precipitation out onto the plains. Although
the winds will decrease somewhat after the passage of the
disturbance, the northwesterly flow aloft will remain fairly moist,
so have kept the chance for precipitation above climatological
normals across the area into Tuesday. The breezy winds throughout
the period will keep temperatures around 10 degrees above normal.
The warmest day of the period appears to be Monday, when most lower
elevation locations should get well into the 40s.
Coulston

&&

.AVIATION...
UPDATED 0540Z.
Low clouds and dense fog will continue to affect portions of the
region over the next 24 hours. Cut Bank will see the greatest
impacts with widespread VLIFR conditions continuing through much of
the night. Patchy dense fog will be possible elsewhere...with
Bozeman and Great Falls being the 2nd best areas to see areas of
dense fog. Isolated snow showers will develop over far Southwest MT
mainly after 21z Tue...and spread northward into Central MT after
00z Wed. Brusda

&&

.PRELIMINARY POINT TEMPS/POPS...
GTF  28  22  36  24 /   0  20  30  10
CTB  25  17  34  21 /   0  10  10  10
HLN  30  20  32  19 /  10  30  20  10
BZN  29  19  33  15 /  10  30  20  10
WEY  29  18  31  14 /  40  50  40  20
DLN  31  21  34  19 /  20  30  10  10
HVR  26  15  30  20 /   0  10  20  10
LWT  30  22  37  21 /   0  20  20  10

&&

.TFX WATCHES/WARNINGS/ADVISORIES...
FREEZING FOG ADVISORY until 11 AM MST this morning Cascade...
Eastern Glacier...Eastern Pondera...Eastern Teton...Judith
Basin...Northern Rocky Mountain Front...Southern Rocky Mountain
Front...Toole.

&&

$$

weather.gov/greatfalls
www.twitter.com/NWSGreatFalls
www.facebook.com/NWSGreatFalls





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