Area Forecast Discussion
Issued by NWS Billings, MT

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000
FXUS65 KBYZ 310254
AFDBYZ

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE BILLINGS MT
854 PM MDT THU OCT 30 2014

.UPDATE...

MAIN UPDATE CONCERNS THIS EVENING ARE FOR SOUTHEAST MONTANA. COLD
HIGH PRESSURE OVER THE NORTHERN PLAINS IS INTERACTING WITH
DEVELOPING LOW PRESSURE LEE OF THE DIVIDE. THIS INTERACTION IS
TIGHTENING THE PRESSURE GRADIENT OVER SOUTHEAST MONTANA WHICH WILL
INCREASE WIND SPEEDS OVERNIGHT WITH GUSTS IN BAKER OF 30 TO 35 MPH
BY SUNRISE. HOWEVER...HAVE LOWERED WIND SPEEDS SOME FROM PREVIOUS
FORECAST FOR THE OVERNIGHT AND EARLY FRIDAY MORNING TIME FRAME.
LOWERED SPEEDS DUE TO CLOUD COVER TODAY HOLDING TEMPERATURES IN
THE 30S AND THUS HAVE A STRONG SURFACE INVERSION IN PLACE OVER
THIS AREA AND THUS WILL SEE SOME PROTECTION FROM STRONGER BOUNDARY
LAYER WINDS UNTIL LATE MORNING OR EARLY AFTERNOON. STILL EXPECT A
FEW GUSTS IN THE 45 TO 50 MPH RANGE FOR AREAS EAST OF A MILES CITY
TO BROADUS LINE DURING THE DAY TOMORROW.

STRATUS DECK REMAINS ALONG THE EASTERN BORDER THIS EVENING AND
MODELS NOT SHOWING MUCH OF A RETREAT OVERNIGHT. A FEW MODELS DRAG
THE STRATUS TO THE WEST SOME OVERNIGHT WHILE MOST ARE BASICALLY
HOLDING IT IN PLACE. THINK AS WINDS SHIFT TO THE SOUTHEAST LATE
TONIGHT COULD SEE A SURGE OF STRATUS TO THE WEST A BIT AND
INCREASED CLOUD COVER SOME INTO CUSTER AND POWDER RIVER COUNTIES.
CAN`T RULE OUT SOME PATCHY FOG FOR A FEW LOW LYING PROTECTED
LOCATIONS ALONG THE EASTERN STATE LINE EITHER...MAINLY BEFORE 3
AM.

FOR THE REST OF THE AREA MID TO UPPER LEVEL CLOUD COVER WILL
SPREAD OVER THE AREA THROUGH THE NIGHT WHICH WILL HELP HOLD
TEMPERATURES IN THE MID 30S FOR LOWS. CHAMBERS

&&

.SHORT TERM...VALID FOR FRI AND SAT...

HIGH PRESSURE RIDGE AND AXIS WILL HOLD IN PLACE OVER THE FORECAST
AREA TONIGHT RESULTING IN MOSTLY CLEAR TO PARTLY CLOUDY SKIES. THE
LOW STRATUS DECK ASSOCIATED WITH A BACKDOOR FRONT THAT WAS ACROSS
FALLON...AND MOST OF CARTER AND CUSTER COUNTIES MOST OF TODAY IS
SLOWLY RETREATING NORTHEAST THIS AFTERNOON AS JUST FALLON COUNTY
IS UNDER THIS CLOUD DECK NOW. SOME HIGH LEVEL CLOUDS ARE MOVING
ALONG THE PERIPHERY OF THE RIDGE ACROSS THE PACIFIC NORTHWEST INTO
WESTERN MONTANA AND THESE MAY SPILL EAST OF THE FRONT RANGE
OVERNIGHT. IN ANY CASE...CONDITIONS WILL BE DRY TONIGHT WITH
OVERNIGHT LOWS 2 OR 3 DEGREES OR SO WARMER THAN THIS MORNING.

SURFACE HIGH PRESSURE OVER SOUTHERN CANADA WILL MOVE SOUTH ACROSS
THE EASTERN DAKOTAS BY FRIDAY MORNING. THIS WILL SET UP TIGHT
PRESSURE GRADIENTS ACROSS EASTERN MONTANA. A LOW-LEVEL JET WILL
ALSO FORM ACROSS THE WESTERN HIGH PLAINS. THIS WILL ALL RESULT IN
STRONG SOUTHEAST WINDS TONIGHT THROUGH FRIDAY MORNING ACROSS FAR
SOUTHEAST MONTANA WHERE GUSTS OF 40 TO 50 MPH WILL BE POSSIBLE. AS
THE SURFACE HIGH SHIFTS EAST DURING THE DAY FRIDAY...PRESSURE
GRADIENTS WILL SLACKEN ALONG WITH THE STRONG WIND GUSTS DURING THE
AFTERNOON.

MODELS HAVE COME INTO FAIRLY GOOD AGREEMENT FOR THE STORM SYSTEM
THIS WEEKEND. UPPER LOW AND TROUGH MOVE ONTO THE WEST COAST FRIDAY
NIGHT AND INTO THE GREAT BASIN AREA SATURDAY AFTERNOON. AT THE
SAME TIME...A SURFACE LOW WILL DEVELOP OVER SOUTHWEST/SOUTH
CENTRAL MONTANA PULLING IN WARM AIR AHEAD OF THE SYSTEM SO
SATURDAY LOOKS TO BE ANOTHER WARM DAY. THE LOW WILL MOVE INTO
SOUTHEAST MONTANA SATURDAY EVENING AND INTO THE WESTERN DAKOTAS
SUNDAY MORNING. A COLD FRONT WILL SWEEP ACROSS THE FORECAST AREA
AS THE LOW MOVES EAST RESULTING IN WINDS BECOMING GUSTY FROM THE
NORTHWEST SATURDAY NIGHT AND SUNDAY. THE UPPER LOW IS STILL
PROGGED TO MOVE ACROSS SOUTHWEST MONTANA INTO NORTHEAST MONTANA
AND REMAIN JUST TO OUR WEST. AS A RESULT...AT THIS TIME...THE BULK
OF THE PRECIP LOOKS TO BE TO THE NORTHWEST OF OUR FORECAST AREA
CLOSER TO GREAT FALLS. HOWEVER...SHOWERS WILL STILL BE LIKELY
ACROSS OUR WEST AND NORTHWEST AREAS SATURDAY NIGHT INTO SUNDAY
WITH A CHANCE FOR SHOWER ELSEWHERE. A FEW INCHES OF SNOW WILL BE
LIKELY ACROSS THE BEARTOOTH/ABSAROKA AND CRAZY MOUNTAINS WITH SNOW
POSSIBLE FOR THE FOOTHILLS. HOWEVER...THE 0C LINE REMAINS WELL TO
OUR NORTH THROUGH DAYBREAK SUNDAY SO THE FOOTHILLS MAY BE A
RAIN/SNOW MIX SATURDAY NIGHT. WE WILL BE WATCHING THIS CLOSELY
DURING THE NEXT 48 HOURS. HOOLEY


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

MINIMAL CHANGES FOR THE EXTENDED FORECAST PERIOD THIS
AFTERNOON...AS GREATEST IMPACTS CONTINUE TO BE CENTERED AROUND
THE WEATHER SYSTEM CROSSING THE REGION THROUGH THE WEEKEND AND
INTO MONDAY.

THE WEATHER SYSTEM...CONSISTING OF UPPER LEVEL TROF AND SUPPORTING
UPPER LEVEL JET WILL CONTINUE ACROSS THE REGION SUNDAY...AND
SLOWLY MOVE OUT OF THE REGION MONDAY. THE BEST POTENTIAL FOR
PRECIP LOOKS LIKE SUNDAY...AS THE LEFT EXIT REGION OF THE JET
CROSSED THE REGION. PRECIP SHOULD BE MAINLY RAIN FOR THE LOWER
ELEVATIONS...WITH COLDER AIR TO NORTHEAST...BUT CANNOT RULE OUT
MIXED PRECIP...WITH NOD TO NIGHTTIME SNOW IN SOME AREAS. AS FOR
THE HIGH TERRAIN...EXPECT TO SEE AT LEAST A FEW INCHES OF NEW SNOW...WITH
LIGHTER ACCUMULATION IN FOOTHILLS REGIONS.

SHORTWAVE RIDGING DEVELOPS THROUGH THE DAY MONDAY...CLEARING
THINGS OUT PRETTY QUICKLY. UPPER LEVEL FLOW QUICKLY TRANSITIONS TO
ZONAL FLOW OVERNIGHT MONDAY. ZONAL TO SLIGHTLY NORTHWESTERL FLOW
ALOFT PERSISTS THROUGH THE REMAINDER OF THE EXTENDED FORECAST
PERIOD...WITH SEVERAL WEAK WAVES CROSSING THE REGION THROUGH
THURSDAY EVENING. MODELS VERY QUITE A BIT ON TIMING/STRENGTH OF
THESE WAVES. HAVE OPTED FOR SLIGHT MOUNTAIN POPS FROM TUESDAY
NIGHT THROUGH THURSDAY AT THIS TIME...THINKING THAT DOWNSLOPE
FLOW WILL SUPPRESS ANY DEVELOPMENT OFF THE MOUNTAINS. THERE IS
SOME INDICATION OF A STRONGER WAVE CROSSING THE REGION...WITH GFS BEGINNING
WEDNESDAY NIGHT...WHILE EC HOLDS OFF UNTIL ABOUT FRIDAY.

TEMPERATURES WILL BE MAINLY MILD FOLLOWING A COOL START TO THE
EXTENDED PERIOD. HIGHS IN THE 50S CAN BE EXPECTED FOR SUNDAY AND
MONDAY...BUT TEMPS AROUND 60 CAN BE EXPECTED FOR THE REMAINDER OF
THE PERIOD. AAG
&&

.AVIATION...

MVFR TO OCCASIONAL IFR CEILINGS WILL BE POSSIBLE EAST OF A MILES
CITY TO BROADUS LINE TONIGHT INTO TOMORROW MORNING. LOCAL AREAS OF
FOG ARE ALSO POSSIBLE IN THESE AREAS IN MORE SHELTERED LOW LYING
AREAS. VFR CONDITIONS WILL PREVAIL ELSEWHERE. SOUTHEAST WINDS WILL
INCREASE WITH GUSTS OVER 25KTS ACROSS FALLON AND CARTER COUNTIES
OVERNIGHT INTO EARLY TOMORROW MORNING...INCREASING TO 40KTS BY
MID DAY FRIDAY. CHAMBERS

&&

.PRELIMINARY POINT TEMP/POPS...

    FRI     SAT     SUN     MON     TUE     WED     THU
-----------------------------------------------------------
BIL 038/069 044/067 040/050 033/052 032/059 037/061 038/063
    00/B    00/B    66/W    42/W    11/B    11/B    11/B
LVM 036/070 041/067 038/048 028/046 026/051 036/058 036/060
    00/U    02/W    98/W    42/W    11/N    11/B    11/B
HDN 037/069 037/070 034/054 028/053 025/062 031/063 033/065
    00/B    00/B    34/W    42/W    11/U    11/U    11/B
MLS 033/061 034/066 036/051 029/047 026/058 034/059 032/061
    00/N    00/B    33/W    52/W    11/U    11/B    11/B
4BQ 033/060 036/070 039/052 031/047 027/058 035/061 035/062
    00/N    00/B    23/W    42/W    11/U    11/B    11/B
BHK 030/049 030/064 037/050 028/040 024/054 031/057 031/057
    00/N    00/B    12/W    42/W    11/U    11/B    11/B
SHR 036/071 037/073 038/055 028/051 021/062 028/063 030/064
    00/B    00/B    34/W    42/W    11/U    11/U    11/B

&&

.BYZ WATCHES/WARNINGS/ADVISORIES...
MT...NONE.
WY...NONE.

&&

$$
WEATHER.GOV/BILLINGS



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