Area Forecast Discussion
Issued by NWS Billings, MT

Home | Current Version | Previous Version | Text Only | Print | Product List | Glossary On
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50
000
FXUS65 KBYZ 020411
AFDBYZ

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE BILLINGS MT
911 PM MST SUN MAR 1 2015

.UPDATE...
A SHORTWAVE WAS SKIRTING ACROSS N MT THIS EVENING...AS SEEN IN
SATELLITE IMAGERY...BRINGING A FEW CLOUDS TO NW MT.
OTHERWISE...SKIES OVER THE REGION WERE CLEAR. WITH LIGHT WINDS AND
CLEAR SKIES...SOME TEMPERATURES HAD REACHED THEIR FORECAST
LOWS...SO HAVE LOWERED THESE MINS. OTHERWISE...WARM ADVECTION WAS
FORECAST OVERNIGHT IN ADVANCE OF THE ARCTIC FRONT...WHICH WAS
LOCATED FROM S BC TO CENTRAL ALBERTA AT 03Z.

MODELS HAD A GOOD HANDLE ON THE FRONT/S LOCATION THIS EVENING AND
WERE IN GOOD AGREEMENT IN BRINGING IT INTO THE JUDITH GAP AREA
AROUND 18Z...THROUGH KBIL AROUND 21Z AND KSHR AROUND 00Z. THE
SURFACE WIND SHIFT AND INCREASE IN WIND SPEEDS WILL PRECEDE THE
ONSET OF THE SNOW BASED ON THE MODELS...AND WHAT HAS BEEN
OCCURRING IN CANADA. AROUND 6 HOURS OF GOOD INSTABILITY AND A
PERIOD OF STRONG FRONTOGENESIS AS WELL AS Q-VECTOR CONVERGENCE WILL
FOLLOW THE FRONT BRINGING POSSIBLE SNOWFALL RATES OF GREATER THAN
2 IN/HR ACCORDING TO THE SREF...MAINLY W AND S OF KBIL. THE NEW
WRF BROUGHT PRESSURE RISES ON THE ORDER OF 3-5 MB/3 HR THROUGH THE
AREA MON NIGHT WHICH...COMBINED WITH THE INSTABILITY...WILL CREATE
GUSTY WINDS. THE PRESSURE RISES WILL KEEP THE FRONT MOVING AT A
STEADY CLIP WHICH SHOULD LIMIT THE DURATION OF THE HIGH SNOWFALL
RATES. MODEL QPF/S WERE NOT THAT DIFFERENT FROM EACH OTHER AND
SUPPORTED THE GOING FORECAST. NOTED THE SREF PLUMES HAD HIGHER
MEAN SNOWFALL TOTALS FOR THE AREA SO WILL HAVE TO WATCH TRENDS
CAREFULLY.

SNOW SHOULD TAPER OFF OVER MOST AREAS EARLY ON TUE. TUE NIGHT WILL
BE QUITE COLD WITH COLD ADVECTION AND WINDY CONDITIONS OVER THE
AREA. 850 MB TEMPERATURES BY 12Z WED WERE FORECAST TO BE FROM THE
TEENS BELOW ZERO W TO THE LOWER 20S BELOW ZERO E. THE GOING WINTER
STORM WATCHES WERE IN GOOD SHAPE...HIGHLIGHTING THE AREAS THAT
WILL HAVE THE HIGHEST IMPACTS AND/OR SNOW TOTALS FROM THIS SYSTEM.
THE BIGGEST IMPACT WILL BE ON PEOPLE TRAVELING DURING THE TIME OF
THE MOST INTENSE SNOWFALL COMBINED WITH THE GUSTY WINDS. ARTHUR

&&

.SHORT TERM...VALID FOR MON AND TUE...

A CALM AND QUIET NIGHT IS EXPECTED TONIGHT BEFORE A POWERFUL
ARCTIC FRONT SWEEPS SOUTH ACROSS THE AREA ON MONDAY. SKIES REMAIN
SUNNY ACROSS ALL BUT OUR FAR EASTERN AREAS THIS AFTERNOON AND THIS
TREND WILL CONTINUE THROUGH THIS EVENING. A DISTURBANCE MOVING
ACROSS THE DAKOTAS WILL CONTINUE TO BRING A SLIGHT CHANCE FOR SOME
LIGHT SNOW SHOWER ACTIVITY FOR THE REMAINDER OF THIS AFTERNOON BUT
IS EXPECTED TO EXIT THE AREA BY THIS EVENING. SKIES OVERNIGHT WILL
BE MOSTLY CLEAR BUT SOME MID LEVEL CLOUDS ASSOCIATED WITH THE NEXT
SYSTEM ACROSS WESTERN CANADA WILL ENTER AND MOVE ACROSS THE
WESTERN HALF OF OUR FORECAST AREA LATE TONIGHT. OVERNIGHT LOWS
WILL BE A FEW DEGREES WARMER THAN THIS MORNING WITH SINGLE DIGITS
ACROSS THE EAST AND TEENS ELSEWHERE.

THE ARCTIC FRONT WILL BE ON OUR DOORSTEP MONDAY MORNING AND IS
EXPECTED TO MOVE THROUGH JUDITH GAP BY LATE MORNING AND THE
SOUTHEAST CORNER OF THE STATE BY LATE AFTERNOON. HIGH TEMPERATURES
FOR MOST AREAS WILL WARM INTO THE MIDDLE AND UPPER 30S FOR MOST
AREAS AND WILL BE REACHED DURING THE MORNING WITH TEMPERATURES
FALLING QUICKLY DURING THE AFTERNOON AND EARLY EVENING. DYNAMICS
WITH THIS SYSTEM CONTINUE TO BE VERY STRONG FOR ABOUT A 6 TO 12
HOUR PERIOD. THE GFS REMAINS ROBUST IN QPF AMOUNTS BUT THE ECMWF
CONTINUES TO SHOW LESSER AMOUNTS. BELIEVE THE HARDEST IMPACTED
AREAS WILL BE JUDITH GAP...THE BEARTOOTH/RED LODGE FOOTHILLS...AND
SHERIDAN COUNTY. CONFIDENCE FOR WARNING CRITERIA SNOW REMAINS HIGH
FOR THE RED LODGE AREA AND POSSIBLY SOUTHERN BIG HORN COUNTY DOWN
INTO SHERIDAN COUNTY. REMAINING AREAS WITHIN THE CURRENT WINTER
STORM WATCH MAY BE MORE IN THE ADVISORY CATEGORY WITH BLOWING SNOW
AND REDUCED VISIBILITIES A FACTOR. WILL NOT BE MAKING ANY CHANGES
TO THE CURRENT WINTER STORM WATCHES. THE MAIN IMPACT CONTINUES TO
BE STRONG GUSTY WINDS COMBINED WITH HEAVY BURSTS OF SNOW WHICH
WILL SIGNIFICANTLY REDUCE VISIBILITIES FOR A TIME LATE MONDAY
AFTERNOON INTO MONDAY EVENING.

ALL MODELS SHOW THE SYSTEM QUICKLY MOVING SOUTH INTO WYOMING
TUESDAY MORNING. SNOW WILL QUICKLY TAPER OFF FROM NORTH TO SOUTH
TUESDAY MORNING BUT WILL LINGER ACROSS THE BEARTOOTH/BIG HORN
FOOTHILLS LOCATIONS AND SHERIDAN COUNTY. HIGHS TUESDAY WILL ONL
BE IN THE LOWER TEENS AT BEST WITH OVERNIGHT LOWS WEDNESDAY
MORNING IN THE SINGLE DIGITS BELOW ZERO. HOOLEY

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

FLOW BACKS STEADILY WEDNESDAY TO FRIDAY WITH A DRYING AND WARMING
TREND EXPECTED. FRIDAY EVENING INTO THE WEEKEND LOOKING AT THE
UPPER LEVEL RIDGE OVER CALIFORNIA LOSING A BIT OF ITS STRENGTH
WHICH MAY ALLOWS SOME DISTURBANCES TO MOVE ACROSS THE AREA IN
NORTHWEST FLOW ALOFT. SURFACE TRAJECTORIES SHOULD KEEP COLDER
SURFACE AIR AWAY FROM THE REGION. HAVE MOUNTAIN SHOWERS IN THE
FORECASTS AT TIMES DURING THE WEEKEND AND BOOSTED WINDS FOR
HARLOWTON AREA WEDNESDAY NIGHT DURING A KLONDIKE CHINOOK PHASE.
BORSUM
&&

.AVIATION...

VFR CONDITIONS ARE EXPECTED THE REST OF THE NIGHT AND INTO THE
DAY ON MONDAY. A STRONG COLD FRONT WILL PUSH THROUGH THE AREA
MONDAY AFTERNOON AND BRING STRONG NORTHWEST WIND GUSTS OF 30-35
KTS. THE FRONT SHOULD MOVE THROUGH KBIL/KLVM/KMLS BETWEEN 19-21Z
AND THROUGH KSHR BETWEEN 21-23Z. TWH
&&

.PRELIMINARY POINT TEMP/POPS...

    MON     TUE     WED     THU     FRI     SAT     SUN
-----------------------------------------------------------
BIL 015/036 004/014 903/027 015/044 029/047 027/050 029/051
    02/O    86/S    11/B    00/N    01/N    11/U    11/N
LVM 012/036 001/012 907/028 016/044 027/046 027/048 028/050
    04/O    96/S    11/B    00/N    12/W    11/U    11/N
HDN 007/038 008/017 903/025 012/045 025/049 024/051 026/052
    01/U    76/S    11/B    00/B    01/B    11/U    11/B
MLS 008/035 003/011 905/018 009/044 025/044 023/047 026/046
    01/B    42/S    21/B    00/B    11/B    11/U    11/B
4BQ 007/037 005/014 904/018 006/043 022/045 020/048 024/048
    00/U    76/S    11/B    00/B    01/B    10/U    11/B
BHK 001/033 001/010 909/013 004/042 022/041 020/044 023/044
    00/U    42/S    21/B    10/B    01/B    11/U    11/B
SHR 005/037 006/010 910/018 006/042 020/043 021/046 022/048
    01/B    97/S    11/B    00/B    01/B    11/U    11/B

&&

.BYZ WATCHES/WARNINGS/ADVISORIES...
MT...WINTER STORM WATCH IN EFFECT FROM MONDAY EVENING THROUGH
      TUESDAY MORNING FOR ZONES 34-38-39-41-56-64>67.
     WINTER STORM WATCH IN EFFECT FROM MONDAY MORNING THROUGH LATE
      MONDAY NIGHT FOR ZONE 63.
WY...WINTER STORM WATCH IN EFFECT FROM MONDAY EVENING THROUGH
      TUESDAY MORNING FOR ZONES 98-99.

&&

$$
WEATHER.GOV/BILLINGS



USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.