Area Forecast Discussion
Issued by NWS Billings, MT

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FXUS65 KBYZ 131100

Area Forecast Discussion
National Weather Service Billings MT
400 AM MST Mon Nov 13 2017

.SHORT TERM...valid for Tdy and Tue...

Weak high pressure ridging will be over the forecast area today.
This will result in a mostly sunny day. Current satellite showing
an area of clouds over southeast Montana exiting into the Dakotas
with mostly clear skies elsewhere across the forecast area.
Temperatures will be slightly warmer today as lee-side troughing
sets up bringing a downslope flow. Although many areas still have
at least a partial snow cover which has crusted over and this has
been hindering daytime highs the past couple of days. As a
result, we are still going below guidance with temperatures.

Pressure gradients tighten along the Upper Yellowstone and
Stillwater Valleys this afternoon and evening due to lee-side
troughing ahead of a Pacific cold front that will move across the
forecast area tonight. Local wind guidance and model guidance show
a short window of the possibility for advisory winds for the
Livingston area and Beartooth/Absaroka foothills this afternoon
and evening. However, latest guidance has come down just a bit and
pressure gradients do not look too impressive. In addition, the
window for strong wind gusts looks to be small. As a result, we
will hold off on a wind advisory at this time. In any case, we
will continue mention of this with the HWO and weather story. Best
timing for the strongest wind gusts looks to be in the 5pm-9pm

As for precip, expect some rain and snow showers along and just
behind the front tonight into Tuesday morning. Tuesday looks to be
dry by afternoon along with a gusty west to northwest wind behind
the front, especially during the afternoon for areas east of
Billings. Highs for Tuesday will be just a few degrees cooler than
today. Hooley

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

Models remain in pretty good agreement through Friday, with
consistency falling apart for the weekend into early next week.
Overall pattern is zonal to weak ridging which keeps temperatures
near to slightly above seasonal levels, with periods of
gusty/strong winds in the foothills and fairly consistent snow
chances for the mountains on west facing slopes.

Ridging on Wednesday will bring dry and seasonally warm conditions
to the area. Winds will increase in the western foothills heading
into Wednesday night. Thursday is a pre-frontal day so should be
warmer and windier than wednesday with highs possibly making it
into the lower 50s. Cold front pushes through sometime late
afternoon into the evening hours bringing a chance for rain/snow
showers to the lower elevations, with a good chance at
accumulating snow in the mountains. Models hinting at a couple of
inches of accumulation by Friday morning for the western
foothills. Friday looks cooler, and unsettled to start the day
but improving in the afternoon.

For the weekend there is some disagreement with how quickly to
erode the cooler air over the area with the GFS the more
aggressive solution. This also results in more wind for the area
in the GFS. By Monday the operational ECMWF dislodges a chunk of
very cold air and surges it southward across the Montana plains.
GFS is having none of that at this point and even the ensembles
are all over the place with 4 to 6 standard deviations between
high and low temperature members. So, confidence in the forecast
past Friday remains very low, especially heading into early next
week. Chambers



A few areas of fog may linger through 16z over SE MT this morning,
but this will be confined to right in the river valleys. Otherwise
VFR conditions expected today. Winds over western foothills will
increase with gusts to around 40kts by this evening at KLVM.



    Tdy Tue     Wed     Thu     Fri     Sat     Sun
BIL 050 032/046 026/045 033/049 030/041 027/042 029/047
    0/U 04/W    00/B    00/B    42/J    11/B    11/B
LVM 051 033/043 024/044 035/045 026/036 024/037 027/044
    0/N 34/W    10/N    26/W    52/J    11/N    11/N
HDN 053 029/048 023/047 030/052 029/043 026/043 026/049
    0/U 03/W    00/B    00/B    33/J    11/B    00/B
MLS 048 028/046 022/045 029/050 027/040 022/039 025/047
    0/U 02/J    00/B    00/B    33/J    11/B    11/B
4BQ 056 029/048 024/049 031/055 029/042 025/041 026/048
    0/U 02/W    00/U    00/B    12/W    11/B    00/B
BHK 052 027/045 021/041 026/051 026/038 020/035 022/046
    0/U 01/B    00/B    00/B    23/W    11/B    10/B
SHR 056 030/051 022/048 028/054 027/041 022/042 023/048
    0/U 02/W    00/U    00/B    33/J    11/B    00/B




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