Area Forecast Discussion
Issued by NWS Billings, MT

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FXUS65 KBYZ 222137
AFDBYZ

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BILLINGS MT
237 PM MST SAT NOV 22 2014

.SHORT TERM...VALID FOR SUN AND MON...

ACTIVE WEATHER THROUGH THE SHORT TERM. WINDS WILL BE THE MAIN
ISSUE AS SEVERAL EVENTS LOOK TO UNFOLD. THE FIRST EVENT WILL
DEVELOP LATE THIS AFTERNOON AND THIS EVENING FROM BIG TIMBER TO
HARLOWTON. A STRONG COLD FRONT WILL PUSH ACROSS THE AREA AND THE
SURFACE PRESSURE GRADIENT WILL BE ORIENTATED JUST RIGHT TO DRIVE
VERY STRONG WINDS IN THIS CORRIDOR. THE GRADIENT SLACKENS UP A BIT
OVERNIGHT AND WINDS SHOULD DECREASE SOME. THAT BEING SAID...WINDS
WILL STAY UP ALL NIGHT. LIVINGSTON WILL HAVE GUSTY WINDS TOO BUT
WINDS SHOULD STAY BELOW ADVISORY CRITERIA BEHIND THE FRONT AS GAP
FLOW WILL NO LONGER BE A PLAYER.

STRONG WINDS WILL PUSH ACROSS CENTRAL AND EASTERN ZONES TONIGHT.
850MB WINDS INCREASE TO 50KTS OVER CENTRAL ZONES THIS EVENING AND
SPREAD INTO THE EAST TONIGHT. CHANNELED VORTICITY AFFECTS CENTRAL
ZONES AND PROVIDES SOME ASCENT FOR SHOWERS...THIS SHOULD KEEP
WINDS OFF THE SURFACE. THE STRONGER WINDS WILL BE OVER THE EAST
WITH SOME SUBSIDENCE WORKING IN THERE OVERNIGHT. NOT A CLIMATE
FAVORED TIME OF DAY FOR HIGH WINDS...SO WILL NOT ISSUE ANY
HIGHLIGHTS AT THIS TIME. THE STRONG WINDS WILL LINGER IN THE EAST
THROUGH SUNDAY MORNING...THEN DECREASE SUNDAY AFTERNOON AS THE
SURFACE PRESSURE GRADIENT RELAXES.

WINDS WILL INCREASE AGAIN AT LIVINGSTON AND NYE SUNDAY NIGHT.
GRADIENT DOES NOT LOOK TIGHT ENOUGH FOR HIGHLIGHTS AT THIS
TIME...BUT COULD BE CLOSE. BUMPED WINDS UP FOR THAT PERIOD. WINDS
WILL BECOME EVEN STRONGER AT LIVINGSTON AND NYE MONDAY NIGHT.
BUMPED WINDS UP MORE FOR THAT AND MAY HAVE TO ISSUE A HIGHLIGHT
FOR THE MONDAY NIGHT EVENT AT A LATER TIME IF THE MODELS STAY
CONSISTENT.

TEMPERATURES WILL BE COOLER SUNDAY BEHIND THE COLD FRONTAL
PASSAGE TONIGHT. SLIGHT MODERATION IN TEMPERATURES EXPECTED MONDAY
IN DOWNSLOPE FLOW. WILL KEEP SCATTERED POPS GOING TONIGHT AS A
COUPLE OF SHORTWAVES SHOOT ACROSS. THE NEXT STRONGER WAVE WILL
ARRIVE SUNDAY NIGHT AND MONDAY FOR ANOTHER CHANCE OF SHOWERS. TWH

.LONG TERM...VALID FOR TUE...WED...THU...FRI...SAT...

MODELS HAVE BEGIN TO COME IN LINE...ESPECIALLY FOR MID WEEK
POTENTIAL COLD AND SNOW. CONFIDENCE IS SLOWLY INCREASING WITH THE
GFS/ECMWF AND CANADIAN MODEL ALL WITH VERY SIMILAR SOLUTIONS.
TIMING ISSUES STILL CONTINUE WITH THE ARRIVAL OF UPPER LEVEL
IMPULSES MOVING THROUGH. BIGGEST CHANGE TO THE EXTENDED FORECAST
WAS TO BEGIN TRENDING TEMPERATURES DOWNWARD FOR MID WEEK AND
INCREASING POPS.

VERY WINDY PERIOD STARTING OUT TUESDAY NIGHT INTO WEDNESDAY AS A
STRONG +100 KT JET MOVES ACROSS THE AREA. ENERGY MOVING IN FROM
THE NORTHWEST WILL BRING INCREASING MID LEVEL WINDS WITH 70KTS
EXPECTED BY TUESDAY NIGHT AT 700 MB. STABLE AIR AT MOUNTAIN TOP
LEVEL WILL ALLOW STRONG GAP FLOW WINDS TO DEVELOP TUESDAY NIGHT
INTO EARLY WEDNESDAY MORNING. ARCTIC FRONT IS EXPECTED TO MOVE
INTO THE AREA LATE ON WEDNESDAY WITH STRONG BAROCLINIC ZONES
SETTING UP EAST OF BILLINGS. MODELS CONTINUE TO BRING AMPLE
PACIFIC MOISTURE INTO THE AREA WEDNESDAY NIGHT WHICH COMBINED
WITH UPSLOPE FLOW...WILL OVERRIDE THE COLD AIR...GENERATING AREAS
OF SNOW. AS OF NOW...IT LOOKS LIKE OUR FOOTHILLS AND FAR WESTERN
ZONES WILL SEE SIGNIFICANT SNOWFALL BUT THIS AREA WILL MORE THAN
LIKELY EXPAND WITH LATER MODELS RUNS. RICHMOND

&&

.AVIATION...

GUSTY WINDS WILL CONTINUE OVER THE ENTIRE AREA TONIGHT ALONG WITH
SCATTERED RAIN SHOWERS OVER THE PLAINS WITH SNOW SHOWERS IN THE
MOUNTAINS. THE PRECIPITATION WILL BRING PERIODS OF MVFR TO IFR
CONDITIONS ALONG WITH MOUNTAIN OBSCURATIONS. STRONG WINDS WILL
CONTINUE OVER SOUTHEAST MONTANA ON SUNDAY ALONG WITH ISOLATED
SHOWERS REGION WIDE. RICHMOND

&&

.PRELIMINARY POINT TEMP/POPS...

    SUN     MON     TUE     WED     THU     FRI     SAT
-----------------------------------------------------------
BIL 030/042 025/040 027/042 029/042 018/028 016/028 011/033
    22/W    21/N    24/W    63/J    22/J    11/B    11/B
LVM 026/036 023/034 024/041 032/043 024/033 017/032 018/037
    22/J    31/N    24/W    62/W    22/J    11/B    11/B
HDN 028/041 022/039 022/041 024/040 017/029 012/029 010/034
    22/W    23/J    24/W    54/J    32/J    11/B    11/B
MLS 027/034 016/034 020/038 020/032 011/021 009/024 007/028
    44/J    22/J    23/W    34/J    42/J    11/B    11/B
4BQ 026/034 017/034 019/038 022/036 012/024 012/026 007/030
    43/J    23/J    23/W    44/J    32/J    01/B    11/B
BHK 025/028 011/027 018/034 016/025 006/018 008/022 007/025
    45/J    21/B    12/J    33/J    41/B    11/B    11/B
SHR 024/037 019/036 019/039 024/042 018/032 014/030 012/035
    43/W    22/J    24/W    63/J    21/B    11/B    11/B

&&

.BYZ WATCHES/WARNINGS/ADVISORIES...
MT...HIGH WIND WARNING IN EFFECT UNTIL 2 AM MST SUNDAY FOR ZONES
      28-63.
     WIND ADVISORY IN EFFECT UNTIL 2 AM MST SUNDAY FOR ZONE 41.
WY...NONE.

&&

$$
WEATHER.GOV/BILLINGS



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