Area Forecast Discussion
Issued by NWS Billings, MT

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FXUS65 KBYZ 150937

Area Forecast Discussion
National Weather Service Billings MT
237 AM MST Sun Jan 15 2017

.SHORT TERM...valid for Tdy and Mon...

Very few changes were made to the short term forecast with this
issuance. Models continue to be in good agreement through Monday.
A split flow aloft will be over the forecast area today as upper
level energy remains well north and south of Montana. As a result,
skies will be mostly sunny today. A weak front and some
associated energy will move across the forecast area tonight but
dynamics and moisture are lacking so no precipitation is expected.
Weak lee- side troughing will be in place today resulting in
gusty west/southwest winds from Billings and areas west which will
aid in temperatures a few degrees warmer than Saturday.

For Monday, high pressure ridging and rising heights build across
the forecast area allowing for sunny skies and continued warming
temperatures. However, we will continue to undercut guidance for
highs at most locations today and Monday as guidance has not been
handling the current snow cover well. Stronger lee-side troughing
develops Monday night as low pressure across southern Canada and
high pressure across southern Idaho will result in tightening
pressure gradients across the upper Yellowstone and upper
Stillwater Valleys. Local wind guidance shows advisory wind
probabilities increasing by late Monday night. As a result, I did
increase winds to near advisory levels for these areas after
midnight Monday night. Hooley

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

Strong downsloping and much warmer temperatures expected across
our cwa Tuesday and Wednesday as ridge builds over the region with
40-50 kt winds at 700mb. Confidence is high that we`ll see
advisory level gusts at Livingston and Nye in the Monday night
through Wednesday night time frame, and have increased messaging
for the upcoming strong cross winds on I-90. Along with the wind
will be significant warming with 850mb temps rising to +8C to
+12C. As always it is a tough forecast with so much snow cover,
but the downsloping will be significant, so believe we will
finally scour out the shallow cold air in place. Above normal
temps will continue Thursday but gap winds should begin to
decrease as a more amplified trof approaches from the west.

Greatest chance of precipitation late next week looks to be from
late Thursday into Friday as splitting trof moves through the
northern and central Rockies. Precip type should be rain or mixed
rain/snow showers at lower elevations with a little snow
accumulation over the mountains, but nothing significant. Current
model trends suggest a period of drying Friday night into
Saturday, but ensemble spread is high. Temps should cool toward
normal by the end of the week per the trof passage and much lower

Regarding river ice, it is possible that a brief 3-day period of
above normal temperatures is not enough to generate widespread ice
jam issues, especially with cooler temps coming next weekend. On
the other hand, low temps along the western foothills may stay
above freezing for a couple nights, so believe rivers and streams
in our west will be important to monitor, initially. Stay tuned.




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



    Tdy Mon     Tue     Wed     Thu     Fri     Sat
BIL 031 016/033 021/042 032/047 032/045 027/037 017/030
    0/N 00/N    00/N    00/N    01/B    32/J    11/B
LVM 035 013/037 027/045 032/048 033/047 026/038 016/033
    0/N 00/N    10/N    11/N    12/W    32/W    12/J
HDN 028 007/028 011/039 024/045 025/042 021/034 011/030
    0/U 00/U    00/B    00/B    01/B    32/J    11/B
MLS 025 009/028 012/039 027/041 025/040 023/036 015/029
    0/U 00/B    00/B    00/B    01/B    22/J    11/B
4BQ 028 006/030 009/040 025/045 022/041 021/036 014/029
    0/U 00/B    00/B    00/B    00/B    22/J    21/B
BHK 028 009/026 010/040 027/044 026/041 023/035 017/028
    0/U 00/B    00/B    00/B    00/B    23/J    21/B
SHR 033 007/034 009/040 024/048 023/045 021/036 010/030
    0/U 00/U    00/B    00/B    00/B    32/J    11/B




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