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 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


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