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000
FXUS65 KBYZ 182130
AFDBYZ

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BILLINGS MT
230 PM MST THU DEC 18 2014

.SHORT TERM...VALID FOR FRI AND SAT...

SHORT WAVE TROUGH WILL MOVE ACROSS THE AREA TONIGHT. UPPER LEVEL
FORCING AND MOISTURE LACKING WITH THIS SYSTEM AND WE ONLY EXPECT
ISOLATED SNOW SHOWERS OVER THE MOUNTAINS. AREA DRYING OUT LATE
TONIGHT INTO FRIDAY NIGHT AS SHORT WAVE RIDGING MOVES ACROSS THE
AREA. INCREASED HEIGHTS OVER THE AREA ALONG WITH SOME MIXING ALOFT
WILL COMBINE TO PRODUCE AFTERNOON TEMPERATURES IN THE UPPER 30S
TO LOWER 40S FRIDAY. RIDGE SHIFTING EAST LATE FRIDAY NIGHT AS
ANOTHER TROUGH OF LOW PRESSURE MOVES IN FROM THE WEST. THIS TROUGH
WILL BE SPLITTING AS IT MOVES ACROSS MONTANA ON SATURDAY WITH THE
BEST FORCING STAYING NORTH OF OUR REGION. 850 MB TEMPERATURES
WILL BE WARM WITH A +2C AND WE WILL SEE A MIX OF RAIN AND SNOW
SHOWERS.

FAST ZONAL FLOW SETTING UP SATURDAY NIGHT WITH STRONG 100 KT JET
PUSHING INTO THE REGION. LEE-SIDE TROUGH SETTING UP AHEAD OF
ENERGY MOVING IN FROM THE WEST COAST. THIS ENERGY WILL BRING 700
MB WINDS OF 50 KTS INTO OUR WESTERN AREAS. MODEL CROSS SECTIONS
SHOWING STABLE LAYER TO SET UP AT MOUNTAINS TOP LEVEL AND THIS
WILL BRING GAP FLOW WINDS LATE SATURDAY NIGHT TO THE LIVINGSTON
AND NYE AREAS. PRESSURE GRADIENT WILL BE INCREASING NEAR BIG
TIMBER AND LOCAL WIND GUIDANCE ALSO SHOWING WINDS WILL BE CLOSE TO
ADVISORY LEVEL THERE. HAVE INCREASED WINDS FOR LIVINGSTON/NYE AND
BIG TIMBER SATURDAY NIGHT AND WILL COVER WIND POTENTIAL WITH AN
HWO. MODELS ARE ALL IN GOOD AGREEMENT IN MOVING Q VECTOR
CONVERGENCE ACROSS THE AREA SATURDAY NIGHT. THIS WILL BRING A FEW
SNOW SHOWERS TO THE AREA. STRONGEST LIFT WILL BE OVER OUR
SOUTHWEST MOUNTAINS WITH JET DYNAMICS/Q VECTOR CONVERGENCE AND
OROGRAPHIC LIFTING. SHOULD SEE 3 TO 5 INCHES OF SNOW ABOVE 7000
FEET. PRECIPITATION AMOUNTS WILL BE LIGHT OVER THE PLAINS WITH
STRONG DOWNSLOPE WINDS OVER THE AREA. RICHMOND

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

ACTIVE WEATHER IN STORE FOR THE EXTENDED PERIOD WITH SEVERAL
POTENTIAL IMPACTS TO CONSIDER.

DEEP PACIFIC MOISTURE PLUME WITH A PWAT STANDARDIZED ANOMALY NEAR
+2 EMBEDDED IN WNW FLOW ALOFT WILL IMPACT OUR WESTERN MOUNTAINS
SUNDAY AND MONDAY. THIS WILL RESULT IN A PERIOD OF ACCUMULATING
SNOWFALL AND POTENTIALLY HEAVY AMOUNTS FOR THE WEST ASPECTS OF
THE BEARTOOTH ABSAROKA AND CRAZY MOUNTAINS. LOWER ELEVATIONS WILL
SEE OCCASIONAL SHOWER ACTIVITY...AND CANNOT RULE OUT SOME LIGHT
FREEZING RAIN EAST OF SFC TROF EARLY SUNDAY MORNING AND AGAIN
MONDAY NIGHT.

SUNDAY WILL BEGIN WITH STRONG SW WINDS ALONG THE WESTERN FOOTHILLS
PER 50+ KTS OF 700MB FLOW AND FAIRLY DEEP LEE SIDE SFC TROFFING.
HAVE RAISED WIND SPEEDS FROM LIVINGSTON TO BIG TIMBER AND
HARLOWTON SUNDAY MORNING...WITH A DECREASE EXPECTED BY AFTERNOON
WITH CAA BEHIND MID LEVEL SHORTWAVE...THOUGH SHOULD BE NOTED THAT
W-NW WINDS WILL BECOME GUSTY ACROSS THE LOWER ELEVATIONS. THERE IS
A POSSIBILITY OF ANOTHER PERIOD OF STRONG FOOTHILLS WINDS BY
TUESDAY NIGHT BUT MODELS IN MORE DISAGREEMENT HERE.

TEMPERATURES SUNDAY THROUGH TUESDAY WILL STAY ABOVE NORMAL PER THE
WEST FLOW ALOFT AND PERSISTENT DOWNSLOPE GRADIENTS. HIGHS ON
SUNDAY WILL ACTUALLY PUSH 50F...WITH A BIT OF COOLING MONDAY AND
TUESDAY.

PATTERN SHIFT IS EXPECTED FOR THE MIDDLE OF THE WEEK AS RIDGE
BUILDS OVER THE NW PACIFIC AND TROF SLIDES FROM THE GULF OF AK
THROUGH THE NORTHERN ROCKIES...INTRODUCING NW FLOW TO OUR CWA BY
CHRISTMAS. CONFIDENCE IS HIGH IN THE OVERALL THEME HERE...COLDER
TEMPS AND A GOOD CHANCE OF SNOW...BUT MODELS ARE STILL EVOLVING IN
THE DETAILS. LATEST RUNS SUGGEST STRONGEST FORCING WILL STAY TO
OUR SOUTH WEDNESDAY AND WEDNESDAY NIGHT. THIS WOULD KEEP GREATEST
PCPN TO OUR SOUTH BUT STILL WITH SNOW SHOWERS IN OUR CWA PER THE
CYCLONIC FLOW AND WEAKER SHORTWAVE ACTIVITY. PREVIOUS ECMWF RUNS
HAD DEVELOPED A DEEP UPPER TROF OVER THE GREAT BASIN BUT THE
LATEST RUN HAS SHIFTED TOWARD THE GFS WITH LESS AMPLIFICATION
OVERALL. DIFFERENCES SEEM TO EMERGE FROM HANDLING OF WEAK LOW NEAR
30N 145W...SO EXPECT MORE MODEL CHANGES OVER THE NEXT COUPLE DAYS.
AS FOR THE ACTUAL FORECAST FOR OUR REGION...LOOKS LIKE A GREATER
THAN CLIMO CHANCE OF SNOW AND BELOW NORMAL TEMPS FOR CHRISTMAS...
WITH POTENTIAL FOR ADDITIONAL COOLING BY NEXT WEEKEND.

ANYONE PLANNING TO TRAVEL ANYTIME FROM CHRISTMAS EVE THROUGH NEXT
WEEKEND WILL WANT TO MONITOR THE FORECAST CLOSELY.

JKL
&&

.AVIATION...

VFR FLIGHT CONDITIONS WILL PREVAIL THROUGH TONIGHT WITH SCATTERED
TO BROKEN MID AND HIGH CLOUD. MOUNTAINS WILL BE OBSCURED AT TIMES
WITH A FEW SNOW SHOWERS OVER THE HIGH TERRAIN. SOUTHWEST WINDS
WILL BE GUSTY AT TIMES ALONG THE FOOTHILLS INCLUDING KLVM WITH
GUSTS OF 25-35 KTS. JKL

&&

.PRELIMINARY POINT TEMP/POPS...

    FRI     SAT     SUN     MON     TUE     WED     THU
-----------------------------------------------------------
BIL 025/041 029/040 029/049 037/046 028/042 022/034 016/026
    00/B    31/B    34/W    32/W    22/W    22/J    44/J
LVM 025/042 029/043 030/048 039/046 028/043 021/038 016/027
    11/N    31/N    35/W    44/W    32/W    34/J    44/J
HDN 015/037 020/039 020/049 031/044 019/040 017/034 015/027
    00/B    22/J    24/W    33/W    22/J    22/J    33/J
MLS 018/038 022/040 023/044 029/041 023/037 019/030 013/023
    00/U    13/J    25/W    22/W    22/J    22/J    22/J
4BQ 017/040 019/041 021/046 030/040 021/038 019/033 013/024
    00/B    12/J    14/W    23/W    22/J    22/J    33/J
BHK 017/037 019/041 020/043 025/037 021/035 017/028 011/019
    00/B    03/J    05/W    22/J    22/J    11/B    22/J
SHR 015/038 020/039 019/045 032/043 019/040 017/036 015/027
    01/U    12/J    23/W    33/W    22/J    22/J    44/J

&&

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

&&

$$
WEATHER.GOV/BILLINGS




000
FXUS65 KBYZ 182130
AFDBYZ

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BILLINGS MT
230 PM MST THU DEC 18 2014

.SHORT TERM...VALID FOR FRI AND SAT...

SHORT WAVE TROUGH WILL MOVE ACROSS THE AREA TONIGHT. UPPER LEVEL
FORCING AND MOISTURE LACKING WITH THIS SYSTEM AND WE ONLY EXPECT
ISOLATED SNOW SHOWERS OVER THE MOUNTAINS. AREA DRYING OUT LATE
TONIGHT INTO FRIDAY NIGHT AS SHORT WAVE RIDGING MOVES ACROSS THE
AREA. INCREASED HEIGHTS OVER THE AREA ALONG WITH SOME MIXING ALOFT
WILL COMBINE TO PRODUCE AFTERNOON TEMPERATURES IN THE UPPER 30S
TO LOWER 40S FRIDAY. RIDGE SHIFTING EAST LATE FRIDAY NIGHT AS
ANOTHER TROUGH OF LOW PRESSURE MOVES IN FROM THE WEST. THIS TROUGH
WILL BE SPLITTING AS IT MOVES ACROSS MONTANA ON SATURDAY WITH THE
BEST FORCING STAYING NORTH OF OUR REGION. 850 MB TEMPERATURES
WILL BE WARM WITH A +2C AND WE WILL SEE A MIX OF RAIN AND SNOW
SHOWERS.

FAST ZONAL FLOW SETTING UP SATURDAY NIGHT WITH STRONG 100 KT JET
PUSHING INTO THE REGION. LEE-SIDE TROUGH SETTING UP AHEAD OF
ENERGY MOVING IN FROM THE WEST COAST. THIS ENERGY WILL BRING 700
MB WINDS OF 50 KTS INTO OUR WESTERN AREAS. MODEL CROSS SECTIONS
SHOWING STABLE LAYER TO SET UP AT MOUNTAINS TOP LEVEL AND THIS
WILL BRING GAP FLOW WINDS LATE SATURDAY NIGHT TO THE LIVINGSTON
AND NYE AREAS. PRESSURE GRADIENT WILL BE INCREASING NEAR BIG
TIMBER AND LOCAL WIND GUIDANCE ALSO SHOWING WINDS WILL BE CLOSE TO
ADVISORY LEVEL THERE. HAVE INCREASED WINDS FOR LIVINGSTON/NYE AND
BIG TIMBER SATURDAY NIGHT AND WILL COVER WIND POTENTIAL WITH AN
HWO. MODELS ARE ALL IN GOOD AGREEMENT IN MOVING Q VECTOR
CONVERGENCE ACROSS THE AREA SATURDAY NIGHT. THIS WILL BRING A FEW
SNOW SHOWERS TO THE AREA. STRONGEST LIFT WILL BE OVER OUR
SOUTHWEST MOUNTAINS WITH JET DYNAMICS/Q VECTOR CONVERGENCE AND
OROGRAPHIC LIFTING. SHOULD SEE 3 TO 5 INCHES OF SNOW ABOVE 7000
FEET. PRECIPITATION AMOUNTS WILL BE LIGHT OVER THE PLAINS WITH
STRONG DOWNSLOPE WINDS OVER THE AREA. RICHMOND

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

ACTIVE WEATHER IN STORE FOR THE EXTENDED PERIOD WITH SEVERAL
POTENTIAL IMPACTS TO CONSIDER.

DEEP PACIFIC MOISTURE PLUME WITH A PWAT STANDARDIZED ANOMALY NEAR
+2 EMBEDDED IN WNW FLOW ALOFT WILL IMPACT OUR WESTERN MOUNTAINS
SUNDAY AND MONDAY. THIS WILL RESULT IN A PERIOD OF ACCUMULATING
SNOWFALL AND POTENTIALLY HEAVY AMOUNTS FOR THE WEST ASPECTS OF
THE BEARTOOTH ABSAROKA AND CRAZY MOUNTAINS. LOWER ELEVATIONS WILL
SEE OCCASIONAL SHOWER ACTIVITY...AND CANNOT RULE OUT SOME LIGHT
FREEZING RAIN EAST OF SFC TROF EARLY SUNDAY MORNING AND AGAIN
MONDAY NIGHT.

SUNDAY WILL BEGIN WITH STRONG SW WINDS ALONG THE WESTERN FOOTHILLS
PER 50+ KTS OF 700MB FLOW AND FAIRLY DEEP LEE SIDE SFC TROFFING.
HAVE RAISED WIND SPEEDS FROM LIVINGSTON TO BIG TIMBER AND
HARLOWTON SUNDAY MORNING...WITH A DECREASE EXPECTED BY AFTERNOON
WITH CAA BEHIND MID LEVEL SHORTWAVE...THOUGH SHOULD BE NOTED THAT
W-NW WINDS WILL BECOME GUSTY ACROSS THE LOWER ELEVATIONS. THERE IS
A POSSIBILITY OF ANOTHER PERIOD OF STRONG FOOTHILLS WINDS BY
TUESDAY NIGHT BUT MODELS IN MORE DISAGREEMENT HERE.

TEMPERATURES SUNDAY THROUGH TUESDAY WILL STAY ABOVE NORMAL PER THE
WEST FLOW ALOFT AND PERSISTENT DOWNSLOPE GRADIENTS. HIGHS ON
SUNDAY WILL ACTUALLY PUSH 50F...WITH A BIT OF COOLING MONDAY AND
TUESDAY.

PATTERN SHIFT IS EXPECTED FOR THE MIDDLE OF THE WEEK AS RIDGE
BUILDS OVER THE NW PACIFIC AND TROF SLIDES FROM THE GULF OF AK
THROUGH THE NORTHERN ROCKIES...INTRODUCING NW FLOW TO OUR CWA BY
CHRISTMAS. CONFIDENCE IS HIGH IN THE OVERALL THEME HERE...COLDER
TEMPS AND A GOOD CHANCE OF SNOW...BUT MODELS ARE STILL EVOLVING IN
THE DETAILS. LATEST RUNS SUGGEST STRONGEST FORCING WILL STAY TO
OUR SOUTH WEDNESDAY AND WEDNESDAY NIGHT. THIS WOULD KEEP GREATEST
PCPN TO OUR SOUTH BUT STILL WITH SNOW SHOWERS IN OUR CWA PER THE
CYCLONIC FLOW AND WEAKER SHORTWAVE ACTIVITY. PREVIOUS ECMWF RUNS
HAD DEVELOPED A DEEP UPPER TROF OVER THE GREAT BASIN BUT THE
LATEST RUN HAS SHIFTED TOWARD THE GFS WITH LESS AMPLIFICATION
OVERALL. DIFFERENCES SEEM TO EMERGE FROM HANDLING OF WEAK LOW NEAR
30N 145W...SO EXPECT MORE MODEL CHANGES OVER THE NEXT COUPLE DAYS.
AS FOR THE ACTUAL FORECAST FOR OUR REGION...LOOKS LIKE A GREATER
THAN CLIMO CHANCE OF SNOW AND BELOW NORMAL TEMPS FOR CHRISTMAS...
WITH POTENTIAL FOR ADDITIONAL COOLING BY NEXT WEEKEND.

ANYONE PLANNING TO TRAVEL ANYTIME FROM CHRISTMAS EVE THROUGH NEXT
WEEKEND WILL WANT TO MONITOR THE FORECAST CLOSELY.

JKL
&&

.AVIATION...

VFR FLIGHT CONDITIONS WILL PREVAIL THROUGH TONIGHT WITH SCATTERED
TO BROKEN MID AND HIGH CLOUD. MOUNTAINS WILL BE OBSCURED AT TIMES
WITH A FEW SNOW SHOWERS OVER THE HIGH TERRAIN. SOUTHWEST WINDS
WILL BE GUSTY AT TIMES ALONG THE FOOTHILLS INCLUDING KLVM WITH
GUSTS OF 25-35 KTS. JKL

&&

.PRELIMINARY POINT TEMP/POPS...

    FRI     SAT     SUN     MON     TUE     WED     THU
-----------------------------------------------------------
BIL 025/041 029/040 029/049 037/046 028/042 022/034 016/026
    00/B    31/B    34/W    32/W    22/W    22/J    44/J
LVM 025/042 029/043 030/048 039/046 028/043 021/038 016/027
    11/N    31/N    35/W    44/W    32/W    34/J    44/J
HDN 015/037 020/039 020/049 031/044 019/040 017/034 015/027
    00/B    22/J    24/W    33/W    22/J    22/J    33/J
MLS 018/038 022/040 023/044 029/041 023/037 019/030 013/023
    00/U    13/J    25/W    22/W    22/J    22/J    22/J
4BQ 017/040 019/041 021/046 030/040 021/038 019/033 013/024
    00/B    12/J    14/W    23/W    22/J    22/J    33/J
BHK 017/037 019/041 020/043 025/037 021/035 017/028 011/019
    00/B    03/J    05/W    22/J    22/J    11/B    22/J
SHR 015/038 020/039 019/045 032/043 019/040 017/036 015/027
    01/U    12/J    23/W    33/W    22/J    22/J    44/J

&&

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

&&

$$
WEATHER.GOV/BILLINGS





000
FXUS65 KBYZ 181630
AFDBYZ

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BILLINGS MT
930 AM MST THU DEC 18 2014

.UPDATE...
WEAK UPPER LEVEL LOW OVER SOUTH CENTRAL NORTH DAKOTA IS WEAKENING
RAPIDLY THIS MORNING. LIGHT SNOW OVER THE FAR EASTERN ZONES HAS
ENDED AND HAVE REMOVED POPS FOR THE REMAINDER OF THE MORNING.
LEE-SIDE TROUGH HAS SET UP AHEAD OF AN APPROACHING SHORT WAVE AND
THIS HAS ALLOWED WINDS TO INCREASE IN LIVINGSTON. OCCASIONAL
WINDS GUSTS OF 30 KTS CAN BE EXPECTED THROUGH THE DAY. DID LOWER
TEMPERATURES IN BILLINGS TODAY AS SURFACE ANALYSIS SHOWING COLD
AIR OVER THE BIGHORN BASIN IN WYOMING. SURFACE GRADIENT WILL ALLOW
THIS COLD AIR TO FEED INTO THE CLARKS FORK AND THIS WILL RESULT IN
COOLER AIR ADVECTING INTO BILLINGS. BUFKIT ALSO INDICATING
SOUTHWEST WINDS IN BILLINGS THROUGH THE DAY SO HAVE BACKED OFF ON
HIGHS TO THE UPPER 30S. REST OF THE FORECAST ON TRACK. RICHMOND

&&

.SHORT TERM...VALID FOR TDY AND FRI...

SATELLITE IS SHOWING AN UPPER LEVEL LOW SPINNING SOUTHEAST ACROSS
THE SOUTHEAST PORTIONS OF THE STATE. THIS WEAK DISTURBANCE WILL
BRING A SLIGHT CHANCE FOR SOME FLURRIES ACROSS THE FALLON AND
CARTER COUNTIES THROUGH MID MORNING. CAN`T RULE OUT SOME ISOLATED
POCKETS OF FOG AS WELL ACROSS THE EAST. HOWEVER...THERE IS A BIT
MORE MIXING THAN THE PAST FEW MORNINGS SO ONLY SOME ISOLATED AREAS
ARE EXPECTED THROUGH MID MORNING. OTHERWISE...WEAK LEE-SIDE
TROUGHING WILL SET UP ACROSS OUR FORECAST AREA TODAY RESULTING IN
SOME WIND FOR THE LIVINGSTON AREA AND ADJACENT BEARTOOTH/ABSAROKA
FOOTHILLS. HOWEVER...WINDS ARE NOT EXPECTED TO BECOME STRONG
THOUGH.

AN AMPLIFIED HIGH PRESSURE RIDGE WILL BE OVER THE STATE FRIDAY
BRINGING DRY CONDITIONS ALONG WITH SLIGHTLY WARMER TEMPERATURES. A
SURFACE LOW OVER SOUTHWEST CANADA WILL BRING CONTINUED LEE-SIDE
TROUGHING ACROSS OUR AREA THROUGH THE DAY KEEPING WINDY CONDITIONS
ACROSS THE FOOTHILLS LOCATIONS. AS THE LOW MOVES EAST FRIDAY NIGHT
INTO SATURDAY MORNING IT WILL SWING A PACIFIC FRONT ACROSS THE
AREA...BRINGING A CHANCE FOR SNOW SHOWERS FRIDAY NIGHT INTO
SATURDAY. THERE`S NOT MUCH IF ANY TEMPERATURE DIFFERENCE BEHIND
THE FRONT ON SATURDAY AS READINGS WILL BE SIMILAR TO TODAY AND
FRIDAY WITH MOST LOCATIONS IN THE UPPER 30S TO LOWER 40S. HOOLEY

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

AN ACTIVE EXTENDED PERIOD ESPECIALLY FOR AREA MOUNTAINS. STILL
LOOKS LIKE SOME POTENTIAL FOR SNOW CHRISTMAS EVE INTO CHRISTMAS
DAY.

FOR THIS WEEKEND...SURGE OF PACIFIC MOISTURE PLOWS INTO THE
NORTHERN ROCKIES ON THE NOSE OF A STRONG 160KT JET STREAM. THESE
STRONG JET STREAM WINDS EXTEND HALF WAY ACROSS THE PACIFIC OCEAN
SO WILL SEE A PROLONGED PERIOD OF MOISTURE ADVECTION INTO THE AREA
AS THIS FEATURE WILL PERSIST OVER THE AREA INTO WEDNESDAY. FOR
SATURDAY AND SUNDAY THE JET STREAM WILL BE ORIENTED IN A ZONAL
MANNER WHICH WILL ALLOW LEE SIDE TROFFING AND DOWNSLOPE WARMING TO
BOOST TEMPERATURES WELL ABOVE SEASONAL LEVELS. THIS WOULD NORMALLY
BE A FAIRLY DRY PATTERN BUT THE AMOUNT OF PACIFIC MOISTURE WILL
BRING AT LEAST A CHANCE OF PRECIPITATION TO MOST LOCATIONS...WITH
LIKELY POPS FOR AREA MOUNTAINS ON WEST FACING SLOPES. DESPITE THE
WARM NATURE OF THIS SYSTEM COULD STILL SEE 6 TO 12 INCHES OF SNOW
BY THE END OF THE WEEKEND ON THOSE WEST FACING SLOPES. FOR LOWER
ELEVATIONS THE WARMTH DURING THE DAY WILL PROVIDE MAINLY RAIN AS A
PRECIPITATION TYPE...HOWEVER OVERNIGHT AND INTO THE MORNING HOURS
CAN`T RULE OUT SOME VALLEY FREEZING RAIN OVER SOUTHEAST MONTANA.

EARLY NEXT WEEK...AS WE GET INTO EARLY NEXT WEEK THE ORIENTATION
OF THE JET VEERS MORE NORTHERLY THANKS TO A SUBTROPICAL RIDGE
SLIDING EAST OUT OF HAWAII INTO THE EASTERN PACIFIC OFF
CALIFORNIA. THE STRENGTH OF THE JET DENOTES THE PRESENCE OF COLDER
AIR OVER CANADA WHICH WILL BE ALLOWED TO DROP SOUTHWARD ONCE THE
JET ORIENTATION SHIFTS MORE NORTHERLY ACROSS THE AREA.
TEMPERATURES ON SUNDAY WILL BE NEAR 50 DEGREES IN SOME AREAS BUT
DROP INTO THE 30S BY TUESDAY AND INTO THE UPPER 20S TO LOWER 30S
ON WEDNESDAY. PACIFIC MOISTURE WILL CONTINUE TO FLOW OVER THE AREA
DURING THIS PERIOD KEEPING A CHANCE OF PRECIPITATION IN THE
FORECAST EACH DAY. BEST CHANCES WILL REMAIN IN THE MOUNTAINS BUT
WITH A SHIFT TOWARD THE NORTHERN SLOPES SEEING THE HIGHEST
POPS/SNOW ACCUMULATIONS.

CHRISTMAS EVE/CHRISTMAS DAY...SPLIT IN THE JET OVER THE CENTRAL
PACIFIC LOOKS TO DRIVE THE DEVELOPMENT OF A STRENGTHENING RIDGE
OVER ALASKA FROM WEDNESDAY INTO NEXT WEEKEND. THIS INFLUENCE
DEVELOPS A STRONG KINK IN THE JET OVER THE PACIFIC NORTHWEST ON
WEDNESDAY THAT DROPS INTO THE NORTHERN AND CENTRAL ROCKIES
WEDNESDAY NIGHT INTO THURSDAY AS A DEEPENING STORM SYSTEM. LATEST
PROGS HAVE TRENDED SOUTHWARD...WITH THE BULK OF THIS SYSTEM
HITTING WYOMING WITH THE HEAVIEST SNOWFALL ON THE 00Z RUNS.
HOWEVER THERE IS STILL PLENTY OF TIME FOR A SHIFT IN TRACK AND
STRENGTH WITH THIS SYSTEM. EVEN WHERE IT CURRENTLY IS PROGGED
THERE IS STILL A 20 TO 40 PERCENT CHANCE OF SOME SNOW CHRISTMAS
EVE INTO CHRISTMAS DAY WITH DIFFLUENT SOUTHERLY FLOW ALOFT
COMBINED WITH UPSLOPE SURFACE GRADIENT. WILL HAVE TO KEEP A CLOSE
EYE ON THIS SYSTEM AS THE DOOR TO COLD CANADIAN AIR IS OPEN AND
THERE IS PLENTY OF PACIFIC MOISTURE AVAILABLE TO DEVELOP A
SIGNIFICANT SNOWFALL SOMEWHERE IN THE INTER-MOUNTAIN WEST AND
FRONT RANGE...WHETHER THAT IS OVER MONTANA OR COLORADO IS STILL
IN QUESTION. THOSE PLANNING TRAVEL WEDNESDAY INTO THE WEEKEND
SHOULD BE ALERT TO CHANGES IN THE FORECAST THAT COULD IMPACT
TRAVEL CONDITIONS.

LOOKING OUT JUST A BIT FURTHER THE LATEST ECMWF...AND TO AN
EXTENT THE GFS...HINTS AT AN ARCTIC INTRUSION ON THE HEELS OF
THIS POTENTIAL CHRISTMAS SYSTEM. CHAMBERS


&&

.AVIATION...

LINGERING PATCHY FOG/LOW CLOUD NEAR THE DAKOTAS BORDER WILL
DISSIPATE BY MIDDAY. VFR FLIGHT CONDITIONS WILL OTHERWISE PREVAIL
TODAY AND TONIGHT WITH SCATTERED TO BROKEN MID AND HIGH CLOUD.
MOUNTAINS WILL BE OBSCURED AT TIMES WITH A FEW SNOW SHOWERS OVER
THE HIGH TERRAIN. SOUTHWEST WINDS WILL BE GUSTY AT TIMES ALONG THE
FOOTHILLS INCLUDING KLVM WITH GUSTS OF 25-35 KTS. JKL

&&

.PRELIMINARY POINT TEMP/POPS...

    TDY FRI     SAT     SUN     MON     TUE     WED
-------------------------------------------------------
BIL 038 025/041 029/041 029/046 038/044 026/039 020/032
    0/B 00/B    22/W    24/W    32/W    22/W    22/J
LVM 041 025/042 029/045 030/048 039/047 026/043 019/038
    1/N 11/N    31/B    35/W    44/W    32/W    22/J
HDN 037 015/037 020/040 020/045 031/043 019/038 014/032
    0/B 00/B    22/W    14/W    32/W    22/J    22/J
MLS 038 018/039 022/041 023/044 030/040 023/037 018/030
    0/B 00/B    12/W    03/W    22/W    22/W    11/E
4BQ 041 017/040 019/042 021/046 030/042 021/038 016/033
    0/B 00/B    12/W    03/W    22/W    22/J    11/B
BHK 035 017/037 019/042 020/043 025/038 021/034 015/028
    1/B 00/B    12/J    03/W    22/J    22/J    11/E
SHR 040 015/038 020/040 019/043 032/042 019/039 015/036
    0/B 11/U    12/J    03/W    33/W    22/J    22/J

&&

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

&&

$$
WEATHER.GOV/BILLINGS




000
FXUS65 KBYZ 181630
AFDBYZ

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BILLINGS MT
930 AM MST THU DEC 18 2014

.UPDATE...
WEAK UPPER LEVEL LOW OVER SOUTH CENTRAL NORTH DAKOTA IS WEAKENING
RAPIDLY THIS MORNING. LIGHT SNOW OVER THE FAR EASTERN ZONES HAS
ENDED AND HAVE REMOVED POPS FOR THE REMAINDER OF THE MORNING.
LEE-SIDE TROUGH HAS SET UP AHEAD OF AN APPROACHING SHORT WAVE AND
THIS HAS ALLOWED WINDS TO INCREASE IN LIVINGSTON. OCCASIONAL
WINDS GUSTS OF 30 KTS CAN BE EXPECTED THROUGH THE DAY. DID LOWER
TEMPERATURES IN BILLINGS TODAY AS SURFACE ANALYSIS SHOWING COLD
AIR OVER THE BIGHORN BASIN IN WYOMING. SURFACE GRADIENT WILL ALLOW
THIS COLD AIR TO FEED INTO THE CLARKS FORK AND THIS WILL RESULT IN
COOLER AIR ADVECTING INTO BILLINGS. BUFKIT ALSO INDICATING
SOUTHWEST WINDS IN BILLINGS THROUGH THE DAY SO HAVE BACKED OFF ON
HIGHS TO THE UPPER 30S. REST OF THE FORECAST ON TRACK. RICHMOND

&&

.SHORT TERM...VALID FOR TDY AND FRI...

SATELLITE IS SHOWING AN UPPER LEVEL LOW SPINNING SOUTHEAST ACROSS
THE SOUTHEAST PORTIONS OF THE STATE. THIS WEAK DISTURBANCE WILL
BRING A SLIGHT CHANCE FOR SOME FLURRIES ACROSS THE FALLON AND
CARTER COUNTIES THROUGH MID MORNING. CAN`T RULE OUT SOME ISOLATED
POCKETS OF FOG AS WELL ACROSS THE EAST. HOWEVER...THERE IS A BIT
MORE MIXING THAN THE PAST FEW MORNINGS SO ONLY SOME ISOLATED AREAS
ARE EXPECTED THROUGH MID MORNING. OTHERWISE...WEAK LEE-SIDE
TROUGHING WILL SET UP ACROSS OUR FORECAST AREA TODAY RESULTING IN
SOME WIND FOR THE LIVINGSTON AREA AND ADJACENT BEARTOOTH/ABSAROKA
FOOTHILLS. HOWEVER...WINDS ARE NOT EXPECTED TO BECOME STRONG
THOUGH.

AN AMPLIFIED HIGH PRESSURE RIDGE WILL BE OVER THE STATE FRIDAY
BRINGING DRY CONDITIONS ALONG WITH SLIGHTLY WARMER TEMPERATURES. A
SURFACE LOW OVER SOUTHWEST CANADA WILL BRING CONTINUED LEE-SIDE
TROUGHING ACROSS OUR AREA THROUGH THE DAY KEEPING WINDY CONDITIONS
ACROSS THE FOOTHILLS LOCATIONS. AS THE LOW MOVES EAST FRIDAY NIGHT
INTO SATURDAY MORNING IT WILL SWING A PACIFIC FRONT ACROSS THE
AREA...BRINGING A CHANCE FOR SNOW SHOWERS FRIDAY NIGHT INTO
SATURDAY. THERE`S NOT MUCH IF ANY TEMPERATURE DIFFERENCE BEHIND
THE FRONT ON SATURDAY AS READINGS WILL BE SIMILAR TO TODAY AND
FRIDAY WITH MOST LOCATIONS IN THE UPPER 30S TO LOWER 40S. HOOLEY

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

AN ACTIVE EXTENDED PERIOD ESPECIALLY FOR AREA MOUNTAINS. STILL
LOOKS LIKE SOME POTENTIAL FOR SNOW CHRISTMAS EVE INTO CHRISTMAS
DAY.

FOR THIS WEEKEND...SURGE OF PACIFIC MOISTURE PLOWS INTO THE
NORTHERN ROCKIES ON THE NOSE OF A STRONG 160KT JET STREAM. THESE
STRONG JET STREAM WINDS EXTEND HALF WAY ACROSS THE PACIFIC OCEAN
SO WILL SEE A PROLONGED PERIOD OF MOISTURE ADVECTION INTO THE AREA
AS THIS FEATURE WILL PERSIST OVER THE AREA INTO WEDNESDAY. FOR
SATURDAY AND SUNDAY THE JET STREAM WILL BE ORIENTED IN A ZONAL
MANNER WHICH WILL ALLOW LEE SIDE TROFFING AND DOWNSLOPE WARMING TO
BOOST TEMPERATURES WELL ABOVE SEASONAL LEVELS. THIS WOULD NORMALLY
BE A FAIRLY DRY PATTERN BUT THE AMOUNT OF PACIFIC MOISTURE WILL
BRING AT LEAST A CHANCE OF PRECIPITATION TO MOST LOCATIONS...WITH
LIKELY POPS FOR AREA MOUNTAINS ON WEST FACING SLOPES. DESPITE THE
WARM NATURE OF THIS SYSTEM COULD STILL SEE 6 TO 12 INCHES OF SNOW
BY THE END OF THE WEEKEND ON THOSE WEST FACING SLOPES. FOR LOWER
ELEVATIONS THE WARMTH DURING THE DAY WILL PROVIDE MAINLY RAIN AS A
PRECIPITATION TYPE...HOWEVER OVERNIGHT AND INTO THE MORNING HOURS
CAN`T RULE OUT SOME VALLEY FREEZING RAIN OVER SOUTHEAST MONTANA.

EARLY NEXT WEEK...AS WE GET INTO EARLY NEXT WEEK THE ORIENTATION
OF THE JET VEERS MORE NORTHERLY THANKS TO A SUBTROPICAL RIDGE
SLIDING EAST OUT OF HAWAII INTO THE EASTERN PACIFIC OFF
CALIFORNIA. THE STRENGTH OF THE JET DENOTES THE PRESENCE OF COLDER
AIR OVER CANADA WHICH WILL BE ALLOWED TO DROP SOUTHWARD ONCE THE
JET ORIENTATION SHIFTS MORE NORTHERLY ACROSS THE AREA.
TEMPERATURES ON SUNDAY WILL BE NEAR 50 DEGREES IN SOME AREAS BUT
DROP INTO THE 30S BY TUESDAY AND INTO THE UPPER 20S TO LOWER 30S
ON WEDNESDAY. PACIFIC MOISTURE WILL CONTINUE TO FLOW OVER THE AREA
DURING THIS PERIOD KEEPING A CHANCE OF PRECIPITATION IN THE
FORECAST EACH DAY. BEST CHANCES WILL REMAIN IN THE MOUNTAINS BUT
WITH A SHIFT TOWARD THE NORTHERN SLOPES SEEING THE HIGHEST
POPS/SNOW ACCUMULATIONS.

CHRISTMAS EVE/CHRISTMAS DAY...SPLIT IN THE JET OVER THE CENTRAL
PACIFIC LOOKS TO DRIVE THE DEVELOPMENT OF A STRENGTHENING RIDGE
OVER ALASKA FROM WEDNESDAY INTO NEXT WEEKEND. THIS INFLUENCE
DEVELOPS A STRONG KINK IN THE JET OVER THE PACIFIC NORTHWEST ON
WEDNESDAY THAT DROPS INTO THE NORTHERN AND CENTRAL ROCKIES
WEDNESDAY NIGHT INTO THURSDAY AS A DEEPENING STORM SYSTEM. LATEST
PROGS HAVE TRENDED SOUTHWARD...WITH THE BULK OF THIS SYSTEM
HITTING WYOMING WITH THE HEAVIEST SNOWFALL ON THE 00Z RUNS.
HOWEVER THERE IS STILL PLENTY OF TIME FOR A SHIFT IN TRACK AND
STRENGTH WITH THIS SYSTEM. EVEN WHERE IT CURRENTLY IS PROGGED
THERE IS STILL A 20 TO 40 PERCENT CHANCE OF SOME SNOW CHRISTMAS
EVE INTO CHRISTMAS DAY WITH DIFFLUENT SOUTHERLY FLOW ALOFT
COMBINED WITH UPSLOPE SURFACE GRADIENT. WILL HAVE TO KEEP A CLOSE
EYE ON THIS SYSTEM AS THE DOOR TO COLD CANADIAN AIR IS OPEN AND
THERE IS PLENTY OF PACIFIC MOISTURE AVAILABLE TO DEVELOP A
SIGNIFICANT SNOWFALL SOMEWHERE IN THE INTER-MOUNTAIN WEST AND
FRONT RANGE...WHETHER THAT IS OVER MONTANA OR COLORADO IS STILL
IN QUESTION. THOSE PLANNING TRAVEL WEDNESDAY INTO THE WEEKEND
SHOULD BE ALERT TO CHANGES IN THE FORECAST THAT COULD IMPACT
TRAVEL CONDITIONS.

LOOKING OUT JUST A BIT FURTHER THE LATEST ECMWF...AND TO AN
EXTENT THE GFS...HINTS AT AN ARCTIC INTRUSION ON THE HEELS OF
THIS POTENTIAL CHRISTMAS SYSTEM. CHAMBERS


&&

.AVIATION...

LINGERING PATCHY FOG/LOW CLOUD NEAR THE DAKOTAS BORDER WILL
DISSIPATE BY MIDDAY. VFR FLIGHT CONDITIONS WILL OTHERWISE PREVAIL
TODAY AND TONIGHT WITH SCATTERED TO BROKEN MID AND HIGH CLOUD.
MOUNTAINS WILL BE OBSCURED AT TIMES WITH A FEW SNOW SHOWERS OVER
THE HIGH TERRAIN. SOUTHWEST WINDS WILL BE GUSTY AT TIMES ALONG THE
FOOTHILLS INCLUDING KLVM WITH GUSTS OF 25-35 KTS. JKL

&&

.PRELIMINARY POINT TEMP/POPS...

    TDY FRI     SAT     SUN     MON     TUE     WED
-------------------------------------------------------
BIL 038 025/041 029/041 029/046 038/044 026/039 020/032
    0/B 00/B    22/W    24/W    32/W    22/W    22/J
LVM 041 025/042 029/045 030/048 039/047 026/043 019/038
    1/N 11/N    31/B    35/W    44/W    32/W    22/J
HDN 037 015/037 020/040 020/045 031/043 019/038 014/032
    0/B 00/B    22/W    14/W    32/W    22/J    22/J
MLS 038 018/039 022/041 023/044 030/040 023/037 018/030
    0/B 00/B    12/W    03/W    22/W    22/W    11/E
4BQ 041 017/040 019/042 021/046 030/042 021/038 016/033
    0/B 00/B    12/W    03/W    22/W    22/J    11/B
BHK 035 017/037 019/042 020/043 025/038 021/034 015/028
    1/B 00/B    12/J    03/W    22/J    22/J    11/E
SHR 040 015/038 020/040 019/043 032/042 019/039 015/036
    0/B 11/U    12/J    03/W    33/W    22/J    22/J

&&

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

&&

$$
WEATHER.GOV/BILLINGS





000
FXUS65 KBYZ 181017
AFDBYZ

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BILLINGS MT
317 AM MST THU DEC 18 2014

.SHORT TERM...VALID FOR TDY AND FRI...

SATELLITE IS SHOWING AN UPPER LEVEL LOW SPINNING SOUTHEAST ACROSS
THE SOUTHEAST PORTIONS OF THE STATE. THIS WEAK DISTURBANCE WILL
BRING A SLIGHT CHANCE FOR SOME FLURRIES ACROSS THE FALLON AND
CARTER COUNTIES THROUGH MID MORNING. CAN`T RULE OUT SOME ISOLATED
POCKETS OF FOG AS WELL ACROSS THE EAST. HOWEVER...THERE IS A BIT
MORE MIXING THAN THE PAST FEW MORNINGS SO ONLY SOME ISOLATED AREAS
ARE EXPECTED THROUGH MID MORNING. OTHERWISE...WEAK LEE-SIDE
TROUGHING WILL SET UP ACROSS OUR FORECAST AREA TODAY RESULTING IN
SOME WIND FOR THE LIVINGSTON AREA AND ADJACENT BEARTOOTH/ABSAROKA
FOOTHILLS. HOWEVER...WINDS ARE NOT EXPECTED TO BECOME STRONG
THOUGH.

AN AMPLIFIED HIGH PRESSURE RIDGE WILL BE OVER THE STATE FRIDAY
BRINGING DRY CONDITIONS ALONG WITH SLIGHTLY WARMER TEMPERATURES. A
SURFACE LOW OVER SOUTHWEST CANADA WILL BRING CONTINUED LEE-SIDE
TROUGHING ACROSS OUR AREA THROUGH THE DAY KEEPING WINDY CONDITIONS
ACROSS THE FOOTHILLS LOCATIONS. AS THE LOW MOVES EAST FRIDAY NIGHT
INTO SATURDAY MORNING IT WILL SWING A PACIFIC FRONT ACROSS THE
AREA...BRINGING A CHANCE FOR SNOW SHOWERS FRIDAY NIGHT INTO
SATURDAY. THERE`S NOT MUCH IF ANY TEMPERATURE DIFFERENCE BEHIND
THE FRONT ON SATURDAY AS READINGS WILL BE SIMILAR TO TODAY AND
FRIDAY WITH MOST LOCATIONS IN THE UPPER 30S TO LOWER 40S. HOOLEY


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

AN ACTIVE EXTENDED PERIOD ESPECIALLY FOR AREA MOUNTAINS. STILL
LOOKS LIKE SOME POTENTIAL FOR SNOW CHRISTMAS EVE INTO CHRISTMAS
DAY.

FOR THIS WEEKEND...SURGE OF PACIFIC MOISTURE PLOWS INTO THE
NORTHERN ROCKIES ON THE NOSE OF A STRONG 160KT JET STREAM. THESE
STRONG JET STREAM WINDS EXTEND HALF WAY ACROSS THE PACIFIC OCEAN
SO WILL SEE A PROLONGED PERIOD OF MOISTURE ADVECTION INTO THE AREA
AS THIS FEATURE WILL PERSIST OVER THE AREA INTO WEDNESDAY. FOR
SATURDAY AND SUNDAY THE JET STREAM WILL BE ORIENTED IN A ZONAL
MANNER WHICH WILL ALLOW LEE SIDE TROFFING AND DOWNSLOPE WARMING TO
BOOST TEMPERATURES WELL ABOVE SEASONAL LEVELS. THIS WOULD NORMALLY
BE A FAIRLY DRY PATTERN BUT THE AMOUNT OF PACIFIC MOISTURE WILL
BRING AT LEAST A CHANCE OF PRECIPITATION TO MOST LOCATIONS...WITH
LIKELY POPS FOR AREA MOUNTAINS ON WEST FACING SLOPES. DESPITE THE
WARM NATURE OF THIS SYSTEM COULD STILL SEE 6 TO 12 INCHES OF SNOW
BY THE END OF THE WEEKEND ON THOSE WEST FACING SLOPES. FOR LOWER
ELEVATIONS THE WARMTH DURING THE DAY WILL PROVIDE MAINLY RAIN AS A
PRECIPITATION TYPE...HOWEVER OVERNIGHT AND INTO THE MORNING HOURS
CAN`T RULE OUT SOME VALLEY FREEZING RAIN OVER SOUTHEAST MONTANA.

EARLY NEXT WEEK...AS WE GET INTO EARLY NEXT WEEK THE ORIENTATION
OF THE JET VEERS MORE NORTHERLY THANKS TO A SUBTROPICAL RIDGE
SLIDING EAST OUT OF HAWAII INTO THE EASTERN PACIFIC OFF
CALIFORNIA. THE STRENGTH OF THE JET DENOTES THE PRESENCE OF COLDER
AIR OVER CANADA WHICH WILL BE ALLOWED TO DROP SOUTHWARD ONCE THE
JET ORIENTATION SHIFTS MORE NORTHERLY ACROSS THE AREA.
TEMPERATURES ON SUNDAY WILL BE NEAR 50 DEGREES IN SOME AREAS BUT
DROP INTO THE 30S BY TUESDAY AND INTO THE UPPER 20S TO LOWER 30S
ON WEDNESDAY. PACIFIC MOISTURE WILL CONTINUE TO FLOW OVER THE AREA
DURING THIS PERIOD KEEPING A CHANCE OF PRECIPITATION IN THE
FORECAST EACH DAY. BEST CHANCES WILL REMAIN IN THE MOUNTAINS BUT
WITH A SHIFT TOWARD THE NORTHERN SLOPES SEEING THE HIGHEST
POPS/SNOW ACCUMULATIONS.

CHRISTMAS EVE/CHRISTMAS DAY...SPLIT IN THE JET OVER THE CENTRAL
PACIFIC LOOKS TO DRIVE THE DEVELOPMENT OF A STRENGTHENING RIDGE
OVER ALASKA FROM WEDNESDAY INTO NEXT WEEKEND. THIS INFLUENCE
DEVELOPS A STRONG KINK IN THE JET OVER THE PACIFIC NORTHWEST ON
WEDNESDAY THAT DROPS INTO THE NORTHERN AND CENTRAL ROCKIES
WEDNESDAY NIGHT INTO THURSDAY AS A DEEPENING STORM SYSTEM. LATEST
PROGS HAVE TRENDED SOUTHWARD...WITH THE BULK OF THIS SYSTEM
HITTING WYOMING WITH THE HEAVIEST SNOWFALL ON THE 00Z RUNS.
HOWEVER THERE IS STILL PLENTY OF TIME FOR A SHIFT IN TRACK AND
STRENGTH WITH THIS SYSTEM. EVEN WHERE IT CURRENTLY IS PROGGED
THERE IS STILL A 20 TO 40 PERCENT CHANCE OF SOME SNOW CHRISTMAS
EVE INTO CHRISTMAS DAY WITH DIFFLUENT SOUTHERLY FLOW ALOFT
COMBINED WITH UPSLOPE SURFACE GRADIENT. WILL HAVE TO KEEP A CLOSE
EYE ON THIS SYSTEM AS THE DOOR TO COLD CANADIAN AIR IS OPEN AND
THERE IS PLENTY OF PACIFIC MOISTURE AVAILABLE TO DEVELOP A
SIGNIFICANT SNOWFALL SOMEWHERE IN THE INTER-MOUNTAIN WEST AND
FRONT RANGE...WHETHER THAT IS OVER MONTANA OR COLORADO IS STILL
IN QUESTION. THOSE PLANNING TRAVEL WEDNESDAY INTO THE WEEKEND
SHOULD BE ALERT TO CHANGES IN THE FORECAST THAT COULD IMPACT
TRAVEL CONDITIONS.

LOOKING OUT JUST A BIT FURTHER THE LATEST ECMWF...AND TO AN
EXTENT THE GFS...HINTS AT AN ARCTIC INTRUSION ON THE HEELS OF
THIS POTENTIAL CHRISTMAS SYSTEM. CHAMBERS


&&

.AVIATION...

VFR CONDITIONS WILL PREVAIL WEST OF A MILES CITY TO BROADUS LINE
TODAY...THOUGH OCCASIONAL MOUNTAIN OBSCURATION CAN BE EXPECTED. TO
THE EAST OF THIS LINE MVFR CEILINGS WILL SLOWLY IMPROVE BY MID DAY
WITH VFR CONDITIONS ANTICIPATED BY 20Z. ISOLATED RAIN OR SNOW
SHOWERS CAN BE EXPECTED TODAY POSSIBLY MIXED WITH FREEZING RAIN
EARLY IN THE DAY EAST OF THE MILES CITY TO BROADUS LINE. SOUTHWEST
WINDS WILL BE GUSTY AT TIMES ALONG THE WESTERN FOOTHILLS WITH
OCCASIONAL GUSTS TO 30KTS. CHAMBERS
&&

.PRELIMINARY POINT TEMP/POPS...

    TDY FRI     SAT     SUN     MON     TUE     WED
-------------------------------------------------------
BIL 040 025/041 029/041 029/046 038/044 026/039 020/032
    0/B 00/B    22/W    24/W    32/W    22/W    22/J
LVM 041 025/042 029/045 030/048 039/047 026/043 019/038
    1/N 11/N    31/B    35/W    44/W    32/W    22/J
HDN 037 015/037 020/040 020/045 031/043 019/038 014/032
    0/B 00/B    22/W    14/W    32/W    22/J    22/J
MLS 038 018/039 022/041 023/044 030/040 023/037 018/030
    0/B 00/B    12/W    03/W    22/W    22/W    11/E
4BQ 041 017/040 019/042 021/046 030/042 021/038 016/033
    0/B 00/B    12/W    03/W    22/W    22/J    11/B
BHK 035 017/037 019/042 020/043 025/038 021/034 015/028
    1/M 00/B    12/J    03/W    22/J    22/J    11/E
SHR 040 015/038 020/040 019/043 032/042 019/039 015/036
    0/B 11/U    12/J    03/W    33/W    22/J    22/J

&&

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

&&

$$
WEATHER.GOV/BILLINGS




000
FXUS65 KBYZ 181017
AFDBYZ

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BILLINGS MT
317 AM MST THU DEC 18 2014

.SHORT TERM...VALID FOR TDY AND FRI...

SATELLITE IS SHOWING AN UPPER LEVEL LOW SPINNING SOUTHEAST ACROSS
THE SOUTHEAST PORTIONS OF THE STATE. THIS WEAK DISTURBANCE WILL
BRING A SLIGHT CHANCE FOR SOME FLURRIES ACROSS THE FALLON AND
CARTER COUNTIES THROUGH MID MORNING. CAN`T RULE OUT SOME ISOLATED
POCKETS OF FOG AS WELL ACROSS THE EAST. HOWEVER...THERE IS A BIT
MORE MIXING THAN THE PAST FEW MORNINGS SO ONLY SOME ISOLATED AREAS
ARE EXPECTED THROUGH MID MORNING. OTHERWISE...WEAK LEE-SIDE
TROUGHING WILL SET UP ACROSS OUR FORECAST AREA TODAY RESULTING IN
SOME WIND FOR THE LIVINGSTON AREA AND ADJACENT BEARTOOTH/ABSAROKA
FOOTHILLS. HOWEVER...WINDS ARE NOT EXPECTED TO BECOME STRONG
THOUGH.

AN AMPLIFIED HIGH PRESSURE RIDGE WILL BE OVER THE STATE FRIDAY
BRINGING DRY CONDITIONS ALONG WITH SLIGHTLY WARMER TEMPERATURES. A
SURFACE LOW OVER SOUTHWEST CANADA WILL BRING CONTINUED LEE-SIDE
TROUGHING ACROSS OUR AREA THROUGH THE DAY KEEPING WINDY CONDITIONS
ACROSS THE FOOTHILLS LOCATIONS. AS THE LOW MOVES EAST FRIDAY NIGHT
INTO SATURDAY MORNING IT WILL SWING A PACIFIC FRONT ACROSS THE
AREA...BRINGING A CHANCE FOR SNOW SHOWERS FRIDAY NIGHT INTO
SATURDAY. THERE`S NOT MUCH IF ANY TEMPERATURE DIFFERENCE BEHIND
THE FRONT ON SATURDAY AS READINGS WILL BE SIMILAR TO TODAY AND
FRIDAY WITH MOST LOCATIONS IN THE UPPER 30S TO LOWER 40S. HOOLEY


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

AN ACTIVE EXTENDED PERIOD ESPECIALLY FOR AREA MOUNTAINS. STILL
LOOKS LIKE SOME POTENTIAL FOR SNOW CHRISTMAS EVE INTO CHRISTMAS
DAY.

FOR THIS WEEKEND...SURGE OF PACIFIC MOISTURE PLOWS INTO THE
NORTHERN ROCKIES ON THE NOSE OF A STRONG 160KT JET STREAM. THESE
STRONG JET STREAM WINDS EXTEND HALF WAY ACROSS THE PACIFIC OCEAN
SO WILL SEE A PROLONGED PERIOD OF MOISTURE ADVECTION INTO THE AREA
AS THIS FEATURE WILL PERSIST OVER THE AREA INTO WEDNESDAY. FOR
SATURDAY AND SUNDAY THE JET STREAM WILL BE ORIENTED IN A ZONAL
MANNER WHICH WILL ALLOW LEE SIDE TROFFING AND DOWNSLOPE WARMING TO
BOOST TEMPERATURES WELL ABOVE SEASONAL LEVELS. THIS WOULD NORMALLY
BE A FAIRLY DRY PATTERN BUT THE AMOUNT OF PACIFIC MOISTURE WILL
BRING AT LEAST A CHANCE OF PRECIPITATION TO MOST LOCATIONS...WITH
LIKELY POPS FOR AREA MOUNTAINS ON WEST FACING SLOPES. DESPITE THE
WARM NATURE OF THIS SYSTEM COULD STILL SEE 6 TO 12 INCHES OF SNOW
BY THE END OF THE WEEKEND ON THOSE WEST FACING SLOPES. FOR LOWER
ELEVATIONS THE WARMTH DURING THE DAY WILL PROVIDE MAINLY RAIN AS A
PRECIPITATION TYPE...HOWEVER OVERNIGHT AND INTO THE MORNING HOURS
CAN`T RULE OUT SOME VALLEY FREEZING RAIN OVER SOUTHEAST MONTANA.

EARLY NEXT WEEK...AS WE GET INTO EARLY NEXT WEEK THE ORIENTATION
OF THE JET VEERS MORE NORTHERLY THANKS TO A SUBTROPICAL RIDGE
SLIDING EAST OUT OF HAWAII INTO THE EASTERN PACIFIC OFF
CALIFORNIA. THE STRENGTH OF THE JET DENOTES THE PRESENCE OF COLDER
AIR OVER CANADA WHICH WILL BE ALLOWED TO DROP SOUTHWARD ONCE THE
JET ORIENTATION SHIFTS MORE NORTHERLY ACROSS THE AREA.
TEMPERATURES ON SUNDAY WILL BE NEAR 50 DEGREES IN SOME AREAS BUT
DROP INTO THE 30S BY TUESDAY AND INTO THE UPPER 20S TO LOWER 30S
ON WEDNESDAY. PACIFIC MOISTURE WILL CONTINUE TO FLOW OVER THE AREA
DURING THIS PERIOD KEEPING A CHANCE OF PRECIPITATION IN THE
FORECAST EACH DAY. BEST CHANCES WILL REMAIN IN THE MOUNTAINS BUT
WITH A SHIFT TOWARD THE NORTHERN SLOPES SEEING THE HIGHEST
POPS/SNOW ACCUMULATIONS.

CHRISTMAS EVE/CHRISTMAS DAY...SPLIT IN THE JET OVER THE CENTRAL
PACIFIC LOOKS TO DRIVE THE DEVELOPMENT OF A STRENGTHENING RIDGE
OVER ALASKA FROM WEDNESDAY INTO NEXT WEEKEND. THIS INFLUENCE
DEVELOPS A STRONG KINK IN THE JET OVER THE PACIFIC NORTHWEST ON
WEDNESDAY THAT DROPS INTO THE NORTHERN AND CENTRAL ROCKIES
WEDNESDAY NIGHT INTO THURSDAY AS A DEEPENING STORM SYSTEM. LATEST
PROGS HAVE TRENDED SOUTHWARD...WITH THE BULK OF THIS SYSTEM
HITTING WYOMING WITH THE HEAVIEST SNOWFALL ON THE 00Z RUNS.
HOWEVER THERE IS STILL PLENTY OF TIME FOR A SHIFT IN TRACK AND
STRENGTH WITH THIS SYSTEM. EVEN WHERE IT CURRENTLY IS PROGGED
THERE IS STILL A 20 TO 40 PERCENT CHANCE OF SOME SNOW CHRISTMAS
EVE INTO CHRISTMAS DAY WITH DIFFLUENT SOUTHERLY FLOW ALOFT
COMBINED WITH UPSLOPE SURFACE GRADIENT. WILL HAVE TO KEEP A CLOSE
EYE ON THIS SYSTEM AS THE DOOR TO COLD CANADIAN AIR IS OPEN AND
THERE IS PLENTY OF PACIFIC MOISTURE AVAILABLE TO DEVELOP A
SIGNIFICANT SNOWFALL SOMEWHERE IN THE INTER-MOUNTAIN WEST AND
FRONT RANGE...WHETHER THAT IS OVER MONTANA OR COLORADO IS STILL
IN QUESTION. THOSE PLANNING TRAVEL WEDNESDAY INTO THE WEEKEND
SHOULD BE ALERT TO CHANGES IN THE FORECAST THAT COULD IMPACT
TRAVEL CONDITIONS.

LOOKING OUT JUST A BIT FURTHER THE LATEST ECMWF...AND TO AN
EXTENT THE GFS...HINTS AT AN ARCTIC INTRUSION ON THE HEELS OF
THIS POTENTIAL CHRISTMAS SYSTEM. CHAMBERS


&&

.AVIATION...

VFR CONDITIONS WILL PREVAIL WEST OF A MILES CITY TO BROADUS LINE
TODAY...THOUGH OCCASIONAL MOUNTAIN OBSCURATION CAN BE EXPECTED. TO
THE EAST OF THIS LINE MVFR CEILINGS WILL SLOWLY IMPROVE BY MID DAY
WITH VFR CONDITIONS ANTICIPATED BY 20Z. ISOLATED RAIN OR SNOW
SHOWERS CAN BE EXPECTED TODAY POSSIBLY MIXED WITH FREEZING RAIN
EARLY IN THE DAY EAST OF THE MILES CITY TO BROADUS LINE. SOUTHWEST
WINDS WILL BE GUSTY AT TIMES ALONG THE WESTERN FOOTHILLS WITH
OCCASIONAL GUSTS TO 30KTS. CHAMBERS
&&

.PRELIMINARY POINT TEMP/POPS...

    TDY FRI     SAT     SUN     MON     TUE     WED
-------------------------------------------------------
BIL 040 025/041 029/041 029/046 038/044 026/039 020/032
    0/B 00/B    22/W    24/W    32/W    22/W    22/J
LVM 041 025/042 029/045 030/048 039/047 026/043 019/038
    1/N 11/N    31/B    35/W    44/W    32/W    22/J
HDN 037 015/037 020/040 020/045 031/043 019/038 014/032
    0/B 00/B    22/W    14/W    32/W    22/J    22/J
MLS 038 018/039 022/041 023/044 030/040 023/037 018/030
    0/B 00/B    12/W    03/W    22/W    22/W    11/E
4BQ 041 017/040 019/042 021/046 030/042 021/038 016/033
    0/B 00/B    12/W    03/W    22/W    22/J    11/B
BHK 035 017/037 019/042 020/043 025/038 021/034 015/028
    1/M 00/B    12/J    03/W    22/J    22/J    11/E
SHR 040 015/038 020/040 019/043 032/042 019/039 015/036
    0/B 11/U    12/J    03/W    33/W    22/J    22/J

&&

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

&&

$$
WEATHER.GOV/BILLINGS





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




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 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 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 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 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 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 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 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 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 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 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 160432
AFDBYZ

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE BILLINGS MT
932 PM MST MON DEC 15 2014

.UPDATE...
AREAS WHERE MOST MOISTURE FELL STILL UNDER THE INFLUENCE OF
STRATUS AND THIS IS DELAYING FOG DEVELOPMENT. HRRR SHOWS FOG
DEVELOPING BUT HANGING OVER THE LOWER ELEVATIONS AND NOT IMPACTING
KBIL UNTIL 09Z. THIS IS SUPPORTED BY MODELS SHOWING WINDS DYING
DOWN AT THAT POINT WHICH SHOULD ALLOW FOG LAYER TO DEEPEN. NO
UPDATES AS CURRENT FORECAST LOOKS GOOD. BORSUM

&&

.SHORT TERM...VALID FOR TUE AND WED...

WEAK UPPER LEVEL RIDGING MOVING ACROSS THE AREA TONIGHT. THIS
WILL KEEP DEFORMATION ZONE NORTH OF OUR AREA AND LITTLE CHANCE OF
PRECIPITATION OVERNIGHT. LOW LEVELS WILL REMAIN SATURATED
OVERNIGHT AND FOG WILL BE POSSIBLE FROM BIG TIMBER EAST OVER
NIGHT. A FEW AREAS MAY SEE DENSE FOG BUT THESE AREAS SHOULD BE
ISOLATED AND WILL NOT ISSUE ANY ADVISORY AT THIS TIME. UPPER RIDGE
WILL SHIFT EASTWARD ON TUESDAY WHICH WILL ALLOW PACIFIC ENERGY TO
MOVE IN FROM THE SOUTHWEST. THIS WILL BRING A FEW MOUNTAINS SNOW
SHOWERS. MODELS ARE ALL CONSISTENT IN DEVELOPING AN UPPER LOW
CIRCULATION OVER MONTANA TUESDAY NIGHT AND WEDNESDAY. BOTH
GFS/ECMWF BRING WEAK QG FORCING ACROSS THE AREA AND HAVE INCREASED
POPS OVER OUR WESTERN ZONES FOR THIS TIME PERIOD. MOISTURE WILL
ADVECT BACK INTO THE AREA BUT LOW LEVEL FORCING IS VERY MINIMAL
WITH WEAK WIND FIELD ALOFT. SNOWFALL FROM THIS SYSTEM WILL BE
VERY LIGHT. TEMPERATURES REMAINING NEAR OR SLIGHTLY BELOW SEASONAL
NORMALS FOR TONIGHT THROUGH WEDNESDAY NIGHT WITH LITTLE MIXING TO
TAKE PLACE. RICHMOND


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

WEAK FLOW STILL DOMINATES MUCH OF THE EXTENDED...AND WITH THAT
CONTINUED UNCERTAINTY IN THE MODELS. AS A WEAK WAVE MOVES THROUGH
THE AREA THURSDAY...PRECIP CHANCES REMAIN IN THE WESTERN
MOUNTAINS. FRIDAY A WEAK RIDGE MOVES IN AND THE AREA WILL DRY OUT.

AS WE GO THROUGH THE DAY SUNDAY...THE FLOW ALOFT WILL INCREASE AS
A JET MOVES INTO THE PACIFIC NORTH WEST. OVER THE NEXT COUPLE OF
DAYS...THERE IS SOME DIFFERENCE IN THE MODELS IN HOW THEY HANDLE
EVOLUTION OF THE JET...WHICH WILL BE SOMETHING TO WATCH. THE
PRESSURE GRADIENT WILL START TO TIGHTEN UP AS A SURFACE LOW
DEVELOPS IN SOUTHERN CANADA. SUNDAY NIGHT INTO MONDAY WILL BE
WINDY FROM THE FOOTHILLS OUT TO AROUND BILLINGS.

THE MODELS CONTINUE TO SHOW A FRONT PUSHING THROUGH THE AREA
DURING THE DAY MONDAY. THE LATEST GUIDANCE...ESPECIALLY THE
GFS...HAS TRENDED TEMPERATURES WARMER MONDAY AHEAD OF THE
FRONT...DUE TO COMPRESSIONAL WARMING. HAVE CONTINUED THE CHANCE
POPS ACROSS THE AREA MONDAY AS THE FRONT MOVES THROUGH THE AREA.
TEMPERATURES WILL IN GENERAL BE ABOVE NORMAL. REIMER
&&

.AVIATION...

FOG HAS DEVELOPED IN BILLINGS...AND PATCHY FOG IS POSSIBLE ACROSS
MOST OF THE AREA OVERNIGHT...WITH THE EXCEPTION OF LIVINGSTON.
FOG WILL RESULT IN LOCALIZED IFR OR LOWER CONDITIONS. OTHERWISE
VFR CONDITIONS WILL PREVAIL. OCCASIONAL MOUNTAIN OBSCURATIONS ARE
EXPECTED THROUGHOUT THE NIGHT. AAG

&&

.PRELIMINARY POINT TEMP/POPS...

    TUE     WED     THU     FRI     SAT     SUN     MON
-----------------------------------------------------------
BIL 014/028 019/036 022/038 023/038 024/042 024/043 032/047
    00/B    11/B    11/B    10/U    01/N    11/N    13/W
LVM 015/034 023/042 024/041 023/041 025/043 024/042 033/046
    01/B    22/W    11/B    11/U    11/N    12/W    23/W
HDN 008/029 014/034 014/037 017/037 016/040 018/041 026/045
    00/B    12/J    11/B    10/U    01/B    11/B    13/W
MLS 012/027 015/030 017/037 020/037 018/038 021/040 028/044
    00/B    11/B    11/B    10/U    01/U    11/B    12/W
4BQ 012/030 016/034 017/039 018/040 017/041 020/042 026/046
    00/B    12/J    11/B    10/U    00/U    11/B    13/W
BHK 012/024 011/028 015/035 019/038 018/037 020/039 025/043
    00/B    01/B    11/B    11/U    00/U    11/B    13/W
SHR 009/030 016/036 015/037 016/038 017/040 018/041 024/044
    00/B    11/B    11/B    11/U    01/U    11/B    12/W

&&

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

&&

$$
WEATHER.GOV/BILLINGS




000
FXUS65 KBYZ 160432
AFDBYZ

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE BILLINGS MT
932 PM MST MON DEC 15 2014

.UPDATE...
AREAS WHERE MOST MOISTURE FELL STILL UNDER THE INFLUENCE OF
STRATUS AND THIS IS DELAYING FOG DEVELOPMENT. HRRR SHOWS FOG
DEVELOPING BUT HANGING OVER THE LOWER ELEVATIONS AND NOT IMPACTING
KBIL UNTIL 09Z. THIS IS SUPPORTED BY MODELS SHOWING WINDS DYING
DOWN AT THAT POINT WHICH SHOULD ALLOW FOG LAYER TO DEEPEN. NO
UPDATES AS CURRENT FORECAST LOOKS GOOD. BORSUM

&&

.SHORT TERM...VALID FOR TUE AND WED...

WEAK UPPER LEVEL RIDGING MOVING ACROSS THE AREA TONIGHT. THIS
WILL KEEP DEFORMATION ZONE NORTH OF OUR AREA AND LITTLE CHANCE OF
PRECIPITATION OVERNIGHT. LOW LEVELS WILL REMAIN SATURATED
OVERNIGHT AND FOG WILL BE POSSIBLE FROM BIG TIMBER EAST OVER
NIGHT. A FEW AREAS MAY SEE DENSE FOG BUT THESE AREAS SHOULD BE
ISOLATED AND WILL NOT ISSUE ANY ADVISORY AT THIS TIME. UPPER RIDGE
WILL SHIFT EASTWARD ON TUESDAY WHICH WILL ALLOW PACIFIC ENERGY TO
MOVE IN FROM THE SOUTHWEST. THIS WILL BRING A FEW MOUNTAINS SNOW
SHOWERS. MODELS ARE ALL CONSISTENT IN DEVELOPING AN UPPER LOW
CIRCULATION OVER MONTANA TUESDAY NIGHT AND WEDNESDAY. BOTH
GFS/ECMWF BRING WEAK QG FORCING ACROSS THE AREA AND HAVE INCREASED
POPS OVER OUR WESTERN ZONES FOR THIS TIME PERIOD. MOISTURE WILL
ADVECT BACK INTO THE AREA BUT LOW LEVEL FORCING IS VERY MINIMAL
WITH WEAK WIND FIELD ALOFT. SNOWFALL FROM THIS SYSTEM WILL BE
VERY LIGHT. TEMPERATURES REMAINING NEAR OR SLIGHTLY BELOW SEASONAL
NORMALS FOR TONIGHT THROUGH WEDNESDAY NIGHT WITH LITTLE MIXING TO
TAKE PLACE. RICHMOND


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

WEAK FLOW STILL DOMINATES MUCH OF THE EXTENDED...AND WITH THAT
CONTINUED UNCERTAINTY IN THE MODELS. AS A WEAK WAVE MOVES THROUGH
THE AREA THURSDAY...PRECIP CHANCES REMAIN IN THE WESTERN
MOUNTAINS. FRIDAY A WEAK RIDGE MOVES IN AND THE AREA WILL DRY OUT.

AS WE GO THROUGH THE DAY SUNDAY...THE FLOW ALOFT WILL INCREASE AS
A JET MOVES INTO THE PACIFIC NORTH WEST. OVER THE NEXT COUPLE OF
DAYS...THERE IS SOME DIFFERENCE IN THE MODELS IN HOW THEY HANDLE
EVOLUTION OF THE JET...WHICH WILL BE SOMETHING TO WATCH. THE
PRESSURE GRADIENT WILL START TO TIGHTEN UP AS A SURFACE LOW
DEVELOPS IN SOUTHERN CANADA. SUNDAY NIGHT INTO MONDAY WILL BE
WINDY FROM THE FOOTHILLS OUT TO AROUND BILLINGS.

THE MODELS CONTINUE TO SHOW A FRONT PUSHING THROUGH THE AREA
DURING THE DAY MONDAY. THE LATEST GUIDANCE...ESPECIALLY THE
GFS...HAS TRENDED TEMPERATURES WARMER MONDAY AHEAD OF THE
FRONT...DUE TO COMPRESSIONAL WARMING. HAVE CONTINUED THE CHANCE
POPS ACROSS THE AREA MONDAY AS THE FRONT MOVES THROUGH THE AREA.
TEMPERATURES WILL IN GENERAL BE ABOVE NORMAL. REIMER
&&

.AVIATION...

FOG HAS DEVELOPED IN BILLINGS...AND PATCHY FOG IS POSSIBLE ACROSS
MOST OF THE AREA OVERNIGHT...WITH THE EXCEPTION OF LIVINGSTON.
FOG WILL RESULT IN LOCALIZED IFR OR LOWER CONDITIONS. OTHERWISE
VFR CONDITIONS WILL PREVAIL. OCCASIONAL MOUNTAIN OBSCURATIONS ARE
EXPECTED THROUGHOUT THE NIGHT. AAG

&&

.PRELIMINARY POINT TEMP/POPS...

    TUE     WED     THU     FRI     SAT     SUN     MON
-----------------------------------------------------------
BIL 014/028 019/036 022/038 023/038 024/042 024/043 032/047
    00/B    11/B    11/B    10/U    01/N    11/N    13/W
LVM 015/034 023/042 024/041 023/041 025/043 024/042 033/046
    01/B    22/W    11/B    11/U    11/N    12/W    23/W
HDN 008/029 014/034 014/037 017/037 016/040 018/041 026/045
    00/B    12/J    11/B    10/U    01/B    11/B    13/W
MLS 012/027 015/030 017/037 020/037 018/038 021/040 028/044
    00/B    11/B    11/B    10/U    01/U    11/B    12/W
4BQ 012/030 016/034 017/039 018/040 017/041 020/042 026/046
    00/B    12/J    11/B    10/U    00/U    11/B    13/W
BHK 012/024 011/028 015/035 019/038 018/037 020/039 025/043
    00/B    01/B    11/B    11/U    00/U    11/B    13/W
SHR 009/030 016/036 015/037 016/038 017/040 018/041 024/044
    00/B    11/B    11/B    11/U    01/U    11/B    12/W

&&

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

&&

$$
WEATHER.GOV/BILLINGS





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