Area Forecast Discussion
Issued by NWS Billings, MT

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FXUS65 KBYZ 251021
AFDBYZ

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BILLINGS MT
321 AM MST TUE NOV 25 2014

.SHORT TERM...VALID FOR TDY AND WED...

SHORT TERM FORECAST IN GOOD SHAPE WITH PERIOD OF WINTRY WEATHER ON
TAP FOR THE NEXT COUPLE OF DAYS. SNOW-COVERED AND SLIPPERY
ROADS...WITH REDUCED VISIBILITIES WILL BE GREATEST CONCERNS OVER
THE NEXT FEW DAYS.

STRONG WINDS GUSTING TO 70 MPH ARE STILL OCCURRING IN THE
LIVINGSTON AND NYE AREAS...AND ARE EXPECTED TO CONTINUE UNTIL LATE
THIS MORNING...WHEN THE MOUNTAIN TOP LEVEL INVERSION BREAKS.
THE DISTURBANCE CROSS THE REGION TODAY IS MOVING THROUGH THE
REGION NOW...RADAR ECHO COVERAGE OF SOUTH CENTRAL AND SOUTHEAST
MONTANA INCREASING THROUGH THE NIGHT. THUS FOR WE ARE NOT SEEING
PRECIPITATION IN BILLINGS...BUT RADAR AND SATELLITE DO INDICATE
INCREASING COVERAGE IN THE AREA.

MODELS REMAIN IN GOOD AGREEMENT ON DISTURBANCE BRINGING SNOW
ACROSS THE REGION TODAY...ESPECIALLY IN SOUTHEASTERN WHERE 1 TO 2
INCHES OF SNOWFALL IS EXPECTED. 30 MPH WINDS ARE ALSO
EXPECTED...REDUCING VISIBILITY. ALTHOUGH SLOW TO GET STARTED THIS
MORNING...SNOW SHOULD GET GOING SOON...AS UPPER LEVEL SUPPORT
INCREASES QUICKLY THIS MORNING. THIS SYSTEM MOVES OUT PRETTY
QUICKLY...BUT NEXT SYSTEM IS QUICKLY ON ITS HEALS FOR
TONIGHT...AND WEDNESDAY.

THE SYSTEM MOVING IN TONIGHT ALSO STILL LOOKS ON TRACK...WITH 2
TO 5 INCH SNOWFALL EXPECTED OVER THE LOWER ELEVATIONS OF SOUTH
CENTRAL MT AND NORTH CENTRAL WY. THE TIMING HAS SLOWED
SLIGHTLY...WITH MORE OF THE SNOW EXPECTED WEDNESDAY MORNING THAN
PREVIOUSLY ANTICIPATED. THIS SNOW WILL DEVELOP DUE TO LOW- AND
MID- LEVEL FRONTOGENESIS...COMBINED WITH OVERRUNNING OF MOISTURE
ADVECTION ALOFT OVER THE TOP OF THE FRONTAL ZONE. THIS SYSTEM DOES
CONTINUE TO LACK MUCH IN THE WAY OF UPPER LEVEL SUPPORT...WITH
LITTLE JET SUPPORT AND A LACK OF QG-FORCING ASSOCIATED WITH THE
FRONT. GREATEST CONCERN IS NOT SNOW AMOUNTS...BUT SNOW PACKED AND
SLIPPERY ROAD CONDITIONS. MOUNTAINS WILL SEE MUCH MORE SIGNIFICANT
SNOWS WITH THIS EVEN AS OROGRAPHIC LIFT AS ADDITIONAL SNOW
POTENTIAL WITH MOISTURE ADVECTION. THIS SYSTEM SHOULD EXIT THE
REGION QUICKLY WEDNESDAY NIGHT. AAG

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

BACKING OF THE FLOW ALOFT ON THURSDAY WILL BRING RISING
TEMPERATURES FOR THANKSGIVING AND THE AMOUNT OF WARMTH MAY BE
DEPENDENT ON THE THE SNOW COVER GENERATED BY TUESDAY/WEDNESDAY
SYSTEM. SHOULD EASILY SEE MID 40S WITH SURFACE WINDS DOWNSLOPE
FROM THE SOUTHWEST PUSHING THE COLDER AIR COMPLETELY OUT OF
SOUTHERN MONTANA. FRIDAY STAYS ON THE WARMER SIDE AS THE NEXT
FRONT BEGINS TO MOVE INTO NORTHERN MONTANA SO DESPITE LIGHTER
SURFACE WINDS COMPRESSIONAL WARMING SHOULD HELP TEMPS AGAIN SEE
MID 40S.

COLD FRONT MOVES THROUGH SOUTHERN MONTANA FRIDAY NIGHT WITH A MUCH
COLDER AIRMASS BEHIND IT. ALL MODELS IN PRETTY AGREEMENT IN THE
EXTENDED FORECAST UP THROUGH FRIDAY NIGHT WITH SNOWFALL EXPECTING
TO LAG BEHIND THE INITIAL FRONTAL PASSAGE. AGREEMENT CONTINUES ON
THE MODELS THAT A STREAM OF MOISTURE FLOWS OVER THE AREA ON
SATURDAY AND SATURDAY NIGHT SO WILL HAVE TO WATCH FOR THIS ROUND
OF WINTER WEATHER IMPACTING HOLIDAY RETURN TRAVEL.

SUNDAY THE COLD AIR BECOMES SUFFICIENTLY DEEP TO SHIFT THE BETTER
SNOWFALL SOUTH OF THE REGION SO JUST A COLD DAY. MONDAY THE COLD
AIR MAKES A SOLID RETREAT AS BOTH MODELS SHOW A STRONGER SYSTEM
DEVELOPING UPSTREAM CAUSING FLOW ALOFT TO BECOME SOUTHWESTERLY AND
DEVELOPING LEESIDE TROFFING. BORSUM
&&

.AVIATION...

COLD FRONT MOVING INTO THE REGION TODAY WILL BRING SNOW SHOWERS
PRODUCING BRIEF IFR CONDITIONS FOR SOUTHEAST MONTANA AND AREAS OF
MVFR CONDITIONS. THESE SNOW SHOWERS WILL BEGIN TO SPREAD INTO
CENTRAL AND WESTERN AREAS LATER THIS AFTERNOON. SNOW WILL BECOME
MORE WIDESPREAD FOR KBIL KLVM AND KSHR THIS EVENING FOR AREAS OF
IFR CONDITIONS.

STRONG WINDS OVER THE FOOTHILLS INCLUDING KLVM WILL CONTINUE
THROUGH THE DAY AND DECREASE THIS EVENING WHEN THE FRONT ARRIVES.

BORSUM

&&

.PRELIMINARY POINT TEMP/POPS...

    TDY WED     THU     FRI     SAT     SUN     MON
-------------------------------------------------------
BIL 040 024/036 025/046 034/048 019/020 001/015 009/031
    4/O 89/S    31/N    01/B    33/J    32/J    11/B
LVM 038 027/041 032/048 035/046 026/028 006/023 019/035
    6/O 83/O    21/N    02/W    34/J    42/J    21/B
HDN 039 019/035 019/047 028/048 017/022 002/018 007/029
    4/O 89/O    31/E    01/B    23/J    32/J    11/B
MLS 037 018/028 016/042 029/044 014/016 903/012 004/025
    7/O 48/S    61/E    11/B    33/J    21/B    11/B
4BQ 037 018/031 017/047 027/047 018/024 003/020 009/031
    7/O 46/S    41/E    11/B    23/J    22/J    11/B
BHK 033 014/024 014/037 027/042 015/017 902/011 003/025
    7/O 36/S    52/J    11/B    23/J    21/B    11/B
SHR 037 019/036 020/047 029/049 022/030 006/024 012/035
    6/O 67/S    20/E    00/B    12/J    22/J    11/B

&&

.BYZ WATCHES/WARNINGS/ADVISORIES...
MT...WINTER WEATHER ADVISORY IN EFFECT FROM NOON TODAY TO NOON MST
      WEDNESDAY FOR ZONES 28-40-41-56-63>66.
     WINTER WEATHER ADVISORY IN EFFECT FROM 6 PM THIS EVENING TO 6
      PM MST WEDNESDAY FOR ZONES 29>31-34-35-38-39-42-57-58.
     WIND ADVISORY IN EFFECT UNTIL NOON MST TODAY FOR ZONES 65-66.
     WINTER STORM WARNING IN EFFECT UNTIL NOON MST WEDNESDAY FOR
      ZONES 67-68.
WY...WINTER WEATHER ADVISORY IN EFFECT FROM 6 PM THIS EVENING TO 6
      PM MST WEDNESDAY FOR ZONE 99.
     WINTER WEATHER ADVISORY IN EFFECT UNTIL 6 PM MST WEDNESDAY
      FOR ZONE 98.

&&

$$
WEATHER.GOV/BILLINGS


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