Area Forecast Discussion
Issued by NWS Billings, MT

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FXUS65 KBYZ 240311
AFDBYZ

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE BILLINGS MT
811 PM MST MON FEB 23 2015

.UPDATE...
CURRENT TEMPERATURES ABOUT AS COLD AS ITS GOING TO GET TONIGHT
MOST PLACES AS DEVELOPING LEESIDE TROF WILL KEEP WINDS UP ALL
NIGHT. NO UPDATES. BORSUM

&&

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

MADE A FEW MINOR CHANGES TO THE SHORT TERM FORECAST THIS
AFTERNOON...PRIMARILY CENTERED AROUND INCREASING POPS AND SNOW
OVER NORTH AND EAST FACING UPSLOPE AREAS LATER IN THE PERIOD.

WARMER TEMPERATURES AND GUSTY WINDS WILL CONTINUE THROUGH
TOMORROW. A LOBE OF THE UPPER LEVEL POSITIVELY TILTED PACIFIC
RIDGE STRETCHES OVER THE REGION...BRINGING INCREASING HEIGHTS TO
THE REGION. TUESDAY WILL SEE THE WARMEST TEMPS OF THE
PERIOD...WITH HIGHS AROUND 50 IN MOST AREAS. FORECAST TEMPERATURES
REMAIN ON THE HIGH SIDE OF GUIDANCE...BUT COULD BE A BIT HIGHER
OR LOWER DEPENDING ON TIMING OF THE SHORTWAVES INTO THE REGION.
PROGGED MIX DOWN NUMBERS POINT TO WARMER TEMPS...BUT TREND TOWARD
EARLIER SHORTWAVE AND FRONTAL PASSAGE POINT TOWARD COOLER HIGHS.

INCREASED SHORTWAVE ACTIVITY BEGINS LATE TUESDAY...BREAKING DOWN
THE RIDGE. SHORTWAVE ACTIVITY WILL USHERING COLDER AIR...AND
BRINGING INCREASED PRECIP POTENTIAL TO THE REGION. EXPECT TO SEE
RAIN ACROSS THE REGION LATE TUESDAY EVENING...WHICH WILL SWITCH
TO SNOW OVERNIGHT...AND CONTINUE WITH PRIMARILY SNOW THROUGH
WEDNESDAY NIGHT. TIMING OF PRECIP INTO AND OUT OF THE REGION
CONTINUES TO BE AN ISSUE...WITH RECENT MODEL TRENDS FAVORING
SIGHTLY FASTER ENCROACHMENT OF BACKDOOR FRONT AND PRECIP. THE SFC
HIGH PUSHING SOUTH INTO THE REGION OPENS UP A PERIOD OF NORTH TO
EASTERLY FLOW WEDNESDAY AFTERNOON AND NIGHT. DID RAISE POPS IN
NORTH AND EAST FACING UPSLOPE AREAS THROUGH THIS PERIOD...BUT KEPT
SNOW TOTALS IN THE ADVISORY RANGE AT THIS POINT.

ROAD CONDITIONS FOR THE WEDNESDAY MORNING COMMUTE ARE OF SOME
CONCERN...AS TIMING OF PRECIP TRANSITIONING TO SNOW REMAINS IN
QUESTION...AND TEMPERATURES CONTINUE TO FALL. AAG

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

SEASONABLY COLD AND RELATIVELY QUIET WEATHER IS EXPECTED IN THE
LONG TERM FORECAST PERIOD...WITH HIGHS MAINLY FROM 25 TO 35 F. THE
BEST CHANCE OF LIGHT SNOW LOOKS TO BE CENTERED ON SATURDAY AND
SATURDAY NIGHT OVER SOUTH CENTRAL MT AND NORTH CENTRAL WY...BUT
EVEN THAT/S LOOKING LIKE A LOW-IMPACT/LOW ACCUMULATION EVENT IF IT
OCCURS. THE 12 UTC MULTI-MODEL CONSENSUS WAS USED FOR ALL FORECAST
FIELDS WITH TODAY/S LONG TERM FORECAST GIVEN GOOD MODEL AGREEMENT
IN WHAT WILL LIKELY BE A RELATIVELY LOW-IMPACT WEATHER PATTERN.

ON THE LARGE-SCALE...A PATTERN SHIFT IS EXPECTED BY THE WEEKEND AS
A 500-MB TROUGH DEVELOPS ACROSS THE WESTERN UNITED STATES WHILE
SUB-TROPICAL RIDGING BUILDS INTO THE SOUTHEASTERN PORTION OF THE
COUNTRY. HOWEVER...THE 12 UTC GFS AND ECMWF /AND THEIR PREVIOUS
RUNS/ SHOW A SPLIT IN THE FLOW ALOFT WITH THE MORE DYNAMIC HEIGHT
FALLS DUMPING INTO THE FOUR CORNERS REGION THIS WEEKEND AND ONLY
WEAKER NORTHERN STREAM SHORTWAVE TROUGHING OVER OUR REGION. THAT/S
ENOUGH FOR SOME CHANCE OF LIGHT SNOW CENTERED ON SATURDAY AND
SATURDAY NIGHT...BUT AGAIN IMPACTS WILL BE LOW IF CURRENT MODEL
TRENDS ARE CORRECT. THE COLDEST WEATHER WILL LIKELY BE LATE THIS
WEEK INTO THE WEEKEND...BEFORE SOME RELATIVE WARMING OCCURS BY
MONDAY PER THE 12 UTC MULTI-MODEL BLEND. SCHULTZ

&&

.AVIATION...

VFR CONDITIONS WILL PREVAIL TONIGHT AND INTO THE DAY TUESDAY...BUT
CEILINGS COULD LOWER INTO THE MVFR CATEGORY OVER FAR SOUTHEAST MT
LIKE AROUND KBHK ON TUESDAY. GUSTY WEST-SOUTHWEST WINDS WILL
DIMINISH OVER SOUTHEAST MT BY THIS EVENING...BUT WILL LIKELY STAY
GUSTY INTO TUESDAY ACROSS SOUTH CENTRAL MT IN THE KBIL AND KLVM
AREAS. SCHULTZ

&&

.PRELIMINARY POINT TEMP/POPS...

    MON     TUE     WED     THU     FRI     SAT     SUN
-----------------------------------------------------------
BIL 004/037 026/051 031/037 011/021 002/026 012/025 010/029
    00/N    01/B    77/W    52/J    11/B    23/J    21/B
LVM 906/034 025/047 030/038 013/026 003/032 010/025 000/029
    00/U    01/N    45/W    52/J    22/J    34/J    42/J
HDN 005/040 024/052 030/037 010/022 002/026 009/025 008/029
    00/B    01/B    86/W    41/B    11/U    12/J    22/J
MLS 002/036 024/048 026/029 001/016 001/024 008/024 008/027
    00/B    02/W    36/J    21/U    00/U    11/E    11/B
4BQ 000/034 023/050 026/032 003/017 901/025 005/025 005/027
    00/U    01/B    47/J    31/B    00/U    11/E    21/B
BHK 903/035 021/044 019/022 906/010 905/021 004/022 003/025
    00/N    02/W    45/J    11/U    00/U    11/B    11/B
SHR 905/027 022/048 028/033 010/017 000/023 005/022 005/024
    00/U    01/B    37/J    62/J    11/B    22/J    42/J

&&

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

&&

$$
WEATHER.GOV/BILLINGS


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