Area Forecast Discussion
Issued by NWS Billings, MT

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FXUS65 KBYZ 150404

Area Forecast Discussion
National Weather Service Billings MT
904 PM MST Sat Jan 14 2017


Not many changes to the forecast package tonight. Temperatures
will range from near zero in the river valleys to the upper teens
along the foothills with clear skies expected to continue through
the night. Adjusted winds up slightly in the Big Timber area for
the overnight period. Current observations showing westerly gusts
around 30 mph. As high pressure continues west of the divide,
slight pressure falls east of the divide will be enough to push
winds sporadically into the 30 to 40 mph range through tomorrow.


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

Quiet weather can be expected into Monday as split flow aloft
remains over the region bringing dry conditions to the area. West
to southwest winds of 15 to 35 mph will continue through Monday,
strongest across the western foothills. Blowing snow has become
less of a threat with warming temperatures. A weak clipper system
will cross eastern Montana on Monday. At this time, it looks like
it will bring just some increased cloud cover, but cannot rule out
a shower or two as the jet max associated with the wave moves
overhead. Behind the clipper, winds will begin to increase in the
gap flow areas Monday night as surface high pressure builds over
SE Idaho and lee side troughing develops over the area.

High temperatures in the 20s and 30s can be expected through
Monday. Warmest temperatures can be expected along the foothills
locations with surface pressure gradients supporting downslope
winds. Temperature forecast remains challenging with snowpack and
local drainage effects. Have had another large temperature spread
today with northeastern areas struggling to make it to the teens
and other locations along the foothills pushing 40 plus degrees.
Models continue to struggle with temperatures. Have continued to
undercut guidance by as much as 10 degrees in some locations. STP

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

Again, no significant adjustments to the extended period forecast
for this package. Strong lee side downsloping and much warmer
temperatures are expected in our CWA.

The primary impacts involve gap winds from LIvingston to Big
timber and Nye as lee side trof develops and deepens Monday night
and westerly mid level winds increase. The Gap Flow set up is
expected to last into Thursday. We expect gusts from 50 to over 60
mph during this time. Highlights will likely be issued if model
proggs do not diverge much from their current solutions.

There is a chance of snow over our western mountains Tuesday and
Wednesday, but lower elevations should remain at least mostly dry,
and latest models are drier even for our west aspects. Greater
chance of precipitation begins Thursday as a deeper Pacific trof
pushes inland. Will keep pops broadbrushed across our region
through Friday, but must note that jet forcing looks to sag well
to our south so do not see anything too dynamic for us in the
current model runs.

Regarding temperatures, strong downslope warming will push temps
into the 40s Tuesday through Thursday, and could see some places
reach 50F as 850mb temps approach +10 or +12C by Wednesday.
Nighttime lows could remain above freezing along the foothills and
over some other hills. Looks like gradual cooling as we approach
next weekend, though ensemble spreads are rather wide at this
point. However, we still do not feel there will be any arctic
intrusions during this spell.

Other potential issue could be ice jams by late week as we begin
to melt what is a significant lower elevation snow cover. We will
monitor to see how this unfolds. BT



VFR conditions will prevail across the forecast area through
tonight. Westerly winds gusting 20-30 kts along the foothills
will cause localized drifting snow near KLVM and K3HT. BT


    Sun     Mon     Tue     Wed     Thu     Fri     Sat
BIL 012/031 016/031 021/042 031/047 032/044 025/035 016/028
    00/N    00/U    00/N    00/N    01/B    32/J    11/B
LVM 009/035 013/037 022/044 032/048 032/046 023/036 015/031
    00/N    00/N    10/N    11/N    22/W    32/J    12/J
HDN 906/028 007/028 011/039 024/045 025/041 020/033 009/027
    00/U    00/U    00/B    00/B    01/B    32/J    11/B
MLS 908/025 009/028 012/038 027/045 025/040 022/035 015/028
    00/U    01/B    00/B    00/B    01/B    22/J    11/B
4BQ 901/028 006/030 009/039 025/045 022/040 020/034 012/029
    00/U    01/B    00/B    00/B    01/B    22/J    11/B
BHK 903/028 009/026 010/041 027/045 026/041 022/034 016/028
    00/U    01/B    00/B    00/B    01/B    22/J    11/B
SHR 901/033 007/033 009/043 024/048 023/044 018/035 011/030
    00/U    00/U    00/B    00/B    01/B    22/J    11/B




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