Area Forecast Discussion
Issued by NWS Billings, MT

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000
FXUS65 KBYZ 271038
AFDBYZ

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BILLINGS MT
338 AM MST THU NOV 27 2014

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

TRANSITION TO A WARMER COUPLE OF DAYS BEGINNING THIS MORNING AS A
ENERGETIC FLOW ALOFT GOES THROUGH SUBTLE BACKING AND ALLOWS A WARM
FRONT TO CONTINUE PROGRESSING THROUGH THE REGION. WESTERN ZONES
AND HIGHER ELEVATIONS ALREADY REFLECT THIS TRANSITION WITH
TEMPERATURES IN THE 4OS WHILE COLD AIR LINGERS AS FAR WEST AS
REEDPOINT AND HARLOWTON. VWP PROFILE IN BILLINGS SHOWS 20 TO 25 KT
WESTERLY WINDS 2KFT ABOVE THE GROUND SO TRANSITION TO WARMER
TEMPS WILL PRETTY FAST WHEN IT BEGINS TO OCCUR AROUND DAYBREAK FOR
CENTRAL AREAS. THE SUBSTANTIAL MOISTURE RECEIVED TODAY IS CAUSING
FOG IN SHELTERED AREAS LIKE LIVINGSTON OR WHERE LOCAL UPSLOPE IS
OCCURRING LIKE BILLINGS. THIS SHOULD DISSIPATE AROUND 12Z WHEN THE
MIXING BEGINS TO STRENGTHEN.

FURTHER EAST THE ISENTROPIC LIFT IS STRONGER AND LIGHT
PRECIPITATION IS SHOWING UP ON RADAR BUT COVERAGE IS LIMITED. THIS
SHOULD BE MAINTAINED FOR THE MORNING HOURS BUT WILL DISSIPATE BY
AFTERNOON AS THE STRONG WARMFRONT BLOWS THROUGH THE REGION.
DESPITE SNOW COVER MANY AREAS WILL SEE MID TO UPPER 40S.

WEATHER STORY WILL BE WIND FOR THE NEXT 48 HOURS ALONG WITH
TEMPERATURES CLIMBING INTO THE 50S. LEESIDE TROUGHING DUE TO THE
STRONG WINDS ALOFT AND HIGH PRESSURE OVER SOUTHEAST IDAHO WILL
SUPPORT STRONG GAP FLOW WINDS FOR A LONG DURATION. CURRENT WIND
ADVISORY LOOKS GOOD EXTENDING ALL THE WAY INTO SATURDAY.

FRIDAY IS GOING TO BE A WARM DAY AND IN THE 50S WHICH COULD
APPROACH RECORDS. MOIST GROUND WITH SOME EVAPORATIVE COOLING COULD
HOLD TEMPERATURES INTO THE MID 50S WITH UPPER 40S OVER EXTREME
SOUTHEAST MONTANA. HEIGHTS FALLING OVER THE WESTERN ZONES BEGIN TO
ALLOW AN INCREASE IN MOUNTAIN SHOWER ACTIVITY.

FRIDAY NIGHT LOOKS MILD EARLY BUT AN ARCTIC FRONT WILL BEGIN
MOVING INTO THE NORTHERN ZONES AFTER MIDNIGHT AND REACH BILLINGS
AROUND 4 AM. THIS IS A MUCH MORE POTENT COLD FRONT THEN THE LAST
SYSTEM FROM A TEMPERATURE PERSPECTIVE. PRECIPITATION DOES LOOK TO
LAG INTO THE COLDER AIR SO EXPECT FRIDAY NIGHT TO BE DRY. BORSUM

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

BLAST OF COLD ALONG WITH SOME SNOW ACCUMULATION COMING FOR THIS
WEEKEND. VERY HIGH CONFIDENCE EXISTS IN THIS INITIAL PHASE OF THE
EXTENDED PERIOD...WITH MUCH MORE UNCERTAINTY BEYOND MONDAY.

COLD AIR CURRENTLY POOLING IN NORTHERN BC/ALBERTA WILL PUSH
SOUTHWARD AND REACH OUR CWA SATURDAY. SNOW WILL DEVELOP BEHIND THE
FROPA AND CONTINUE INTO SUNDAY...WITH A TAPERING OFF BY AFTERNOON
AS UPPER TROF WEAKENS AND PUSHES EAST. UNCERTAINTY EXISTS WITH THE
FROPA TIMING BUT FAVOR THE FASTER ECMWF/CANADIAN WHICH SUGGEST
ARRIVAL INTO BILLINGS AROUND 12Z SAT MORNING. STRONG COLD
ADVECTION WILL COMMENCE AND GREATEST THREAT OF PCPN SHOULD LAG
THE FRONT BY SEVERAL HOURS...AND THIS SHOULD GREATLY REDUCE ANY
POTENTIAL FOR A FAST FREEZE OF WET ROADS. HAVE ALSO FAVORED THE
ECMWF WITH REGARD TO THE STRENGTH OF THE UPPER TROF...WITH A BIT
MORE AMPLIFICATION AND DYNAMICS LASTING INTO SUNDAY...SO HAVE
ADJUSTED POPS INTO SUNDAY IN OUR SOUTH TO ACCOUNT FOR THIS.
DENDRITIC LAYER WILL BE DEEP IN THE INITIAL STAGES OF SNOWFALL
BUT AS TEMPS TURN COLDER THE SNOW SHOULD BECOME FINER...IE LATE
SAT NITE INTO SUNDAY. OVERALL LOOKS LIKE A FEW INCHES OF SNOW
ESPECIALLY FOR OUR WEST AND SOUTH...ALONG WITH TEMPS FALLING HARD
TO NEAR ZERO SATURDAY NIGHT. COULD EVEN SEE SOME ISSUES WITH WIND
CHILLS IN OUR EAST BY LATE SAT NIGHT AS CORE OF SFC HIGH NOT
EXPECTED TO ARRIVE UNTIL DURING THE DAY ON SUNDAY. TEMPS ON SUNDAY
WILL BE ONLY IN THE SINGLE DIGITS AND TEENS.

SFC HIGH WILL RETREAT QUICKLY SUNDAY NIGHT AND MONDAY ALLOWING FOR
A MODERATION IN TEMPS...BUT TODAYS MODELS NOT QUITE AS AGGRESSIVE
WITH DOWNSLOPE WARMING/WINDS ON MONDAY WITH MORE ENERGY MOVING IN
QUICKLY FROM THE NW...KEEPING RIDGING SOMEWHAT SUPPRESSED. MODELS
DIVERGE A GREAT DEAL BEYOND MONDAY NIGHT CLIPPER...WITH THE GFS
TAKING WEAK ENERGY FROM THE PAC COAST THRU THE CENTRAL ROCKIES AND
THE ECMWF BUILDING A RIDGE AHEAD OF A WEAKENING PAC LOW. EITHER
WAY DO NOT SEE ANYTHING TOO DYNAMIC IN THE TUE-THU TIME FRAME...
AND WE SHOULD SEE GRADUAL MODERATION WITH TEMPS RETURNING TO NEAR
NORMAL BY THE MID WEEK.
&&

.AVIATION...

AREAS OF FOG...LOW CLOUDS AND LIGHT PCPN WILL PRODUCE MVFR OR
LOWER FLIGHT CONDITIONS EAST OF THE FOOTHILLS EARLY THIS MORNING.
A TRANSITION TO VFR CONDITIONS CAN BE EXPECTED THROUGH THE MORNING
FROM WEST TO EAST AS DRIER DOWNSLOPE WINDS DEVELOP OFF THE MTNS.
EXPECT IMPROVEMENT AT KBIL AND KSHR BY 11-13Z...THEN KMLS AND
KBHK BY 18Z. VFR WILL PREVAIL ACROSS THE AREA TONIGHT. MOUNTAINS
WILL BE OBSCURED OCCASIONALLY OVER THE NEXT 24 HOURS.

WINDS ALONG THE FOOTHILLS WILL BE STRONG TODAY AND TONIGHT WITH
GUSTS LIKELY TO EXCEED 50 KTS AT KLVM. WIND GUSTS TO 30 KTS CAN BE
EXPECTED AT KBIL.

JKL

&&

.PRELIMINARY POINT TEMP/POPS...

    TDY FRI     SAT     SUN     MON     TUE     WED
-------------------------------------------------------
BIL 049 037/054 027/029 902/010 004/031 019/035 015/033
    1/N 01/E    16/S    75/S    10/B    22/J    11/B
LVM 052 043/053 033/035 002/016 007/033 025/037 017/036
    1/N 11/N    37/O    74/S    11/B    22/J    11/B
HDN 050 031/054 024/030 901/010 001/031 014/035 012/034
    1/E 02/W    14/S    74/S    10/B    22/J    11/B
MLS 044 032/048 019/020 903/008 901/026 014/027 007/028
    3/R 11/E    25/S    52/S    10/U    12/J    11/B
4BQ 050 031/053 025/039 002/009 901/031 016/035 011/033
    1/E 11/E    12/S    53/S    10/B    12/J    11/B
BHK 038 029/046 022/024 902/006 903/024 014/026 006/026
    4/R 11/E    14/S    52/S    00/U    11/B    11/B
SHR 050 032/052 028/039 003/011 000/034 019/037 013/036
    1/N 01/E    12/S    76/S    10/B    22/J    11/B

&&

.BYZ WATCHES/WARNINGS/ADVISORIES...
MT...WIND ADVISORY IN EFFECT UNTIL NOON MST SATURDAY FOR ZONES
      65-66.
WY...NONE.

&&

$$
WEATHER.GOV/BILLINGS


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