Area Forecast Discussion
Issued by NWS Billings, MT

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FXUS65 KBYZ 110501

Area Forecast Discussion...Updated
National Weather Service Billings MT
1001 PM MST Sat Dec 10 2016


One more quick update for some patchy fog developing in central
zones along river valleys including in and around Billings. Don`t
expect much impact from this as there is fairly strong northwest
winds just off the surface but could see an hour or two of lower
visibilities in a few locations. This also indicates the heavy
variability of temperatures tonight with the Arctic boundary
trying to hold on in the face of increasing westerly flow scouring
it out. Billings went from 22 at 7pm to 10 at 9pm and will
probably fluctuate that way a couple of times tonight. Adjusted
lows one more time for current trends. Chambers


.SHORT TERM...valid for Sun and Mon...

Bands of snow showers continue across the area as the last push of
energy moves across with the trough axis moving through. Snow
will begin to clear out over the next couple of hours from west to
east. Given that some of the bands are still producing some quick
accumulations, advisories and warnings continue across the area.

Sunday still looks to be the warmest day in the forecast.
Temperatures for most of the area will be in the 20s to near 30
degrees as the arctic air mass continue to retreat east. However
there will be some stronger west winds that will move in as the
cold air moves out. With the light nature of the snow that has
been falling, these gusty winds could lead to some issue with
blowing and drifting snow.

Sunday night another arctic surge will begin to push into Montana.
By Monday morning the arctic should be through most of the state
bring temperatures back into the single digits for highs across
the area, and producing another quick couple of inches across the
area. Reimer

.LONG TERM...valid for Tue...Wed...Thu...Fri...Sat...

A very cold week was in store for the forecast area with chances for
snow increasing by midweek. Models were in good agreement until

Arctic high will be settled over the area on Tue. with low
chances for snow over and near the mountains. Temperatures will be
well below normal in the single digits to teens. A Pacific jet
will buckle northward on Wed. bringing divergence to the area
through Wed. night. Moisture moving north into the area will bring
a slight chance of snow to areas from KLVM to KBIL south Wed.
night. Temperatures will be similar to Tue. on Wednesday. Models
differed in how they handled incoming Pacific shortwaves for Thu.
and Thu. night. Both models had arctic fronts moving back south
into the region, but differed in their moisture depictions. Used
model blends for PoPs which resulted in chances for snow across
the SW part of the area on Thu., and across the entire area Thu.
night. Blended temperatures were in the single digits E to the
lower 20s W. Upper troughing with differences in model details
continued through Saturday. Went with a chance of snow for the
area on Fri. with slight chances for the rest of the period.
Friday looked very cold with 850 mb temperatures around -24
degrees c which resulted in highs above and below zero. Lows Fri.
night could reach the teens below zero to around 20 below zero.
Saturday looked even colder than Fri. with highs around zero.



Snow has just about cleared far SE Montana this evening with VFR
conditions filling in behind it across the rest of the area. MVFR
ceilings from Broadus to Miles City to Roundup will continue to
erode form west to east through the early morning hours. Patchy
fog is trying to develop in the central zones as well, mainly in
the river valleys and could pose an IFR threat in a few locations
including in the vicinity of KBIL. With fairly strong northwest
winds just off the surface don`t expect fog potential to be
widespread or dense at this time. The other hazard to aviation
will be some patchy blowing/drifting snow for areas from KBIL-KSHR
and west, where local MVFR visibilities may exist along with gusts
to 30kts. This includes KSHR, KBIL, and KLVM taf sites. Blowing
snow potential will continue through the day Sunday. Chambers



    Sun     Mon     Tue     Wed     Thu     Fri     Sat
BIL 010/029 007/009 902/012 906/012 001/012 901/004 913/000
    11/E    25/S    41/B    01/U    23/S    43/S    22/J
LVM 018/031 015/018 003/016 902/015 007/018 901/005 913/001
    12/S    46/S    52/J    11/B    23/S    43/S    22/J
HDN 009/029 007/009 902/013 907/014 901/014 902/006 914/000
    10/B    25/S    41/B    11/U    22/S    43/S    22/J
MLS 003/019 001/005 905/010 906/011 904/010 905/003 916/901
    20/B    35/S    21/B    00/U    01/B    33/S    22/J
4BQ 007/026 005/010 904/013 902/014 000/014 000/007 913/901
    30/B    14/S    21/B    00/U    12/S    33/S    22/J
BHK 002/015 901/003 907/006 906/006 907/007 906/002 916/906
    40/B    24/S    11/B    00/U    01/B    33/S    22/J
SHR 014/030 011/015 902/013 905/013 002/018 901/004 912/902
    21/B    14/S    31/B    11/B    22/S    33/S    22/J




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