High Wind in Wyoming, February 9, 2017

Area Forecast Discussion...Updated
National Weather Service Billings MT
915 PM MST Thu Feb 9 2017

.UPDATE...

Windy and mild night in store across most of the forecast area.
Main impact tonight will be continued strong winds for the
Livingston area and adjacent Beartooth Foothills. High wind gusts
have not been reached yet in Livingston but a gust of 67 mph was
reported in Fishtail earlier this evening. As a result, the high
wind warning for these areas will continue through the night.
However, very strong winds have not materialized for the Big
Timber and Harlowton areas. Although 700mb winds are progged to be
around 60-65kts, pressure gradients are becoming less favorable
for these winds to mix down to the surface.

Current surface analysis places a surface low over the Lewistown
area allowing for a tight north/south pressure gradient across the
Upper Yellowstone and Upper Stillwater Valleys, but this is not
favorable for the Big Timber and Harlowton areas. As this surface
low moves east, we are expecting these pressure gradients to
slacken during the next few hours, and as a result, we have
decided to cancel the high wind warnings for the Harlowton and
Big Timber areas.

Elsewhere, expect a mostly cloudy night with much warmer
temperatures expected than last night. Given cloud cover and
continued windy conditions, temperatures are expected to stay
above freezing for most areas from Billings westward. Previous
forecast has this covered. Updated forecast has been sent. Hooley

&&

.SHORT TERM...valid for Fri and Sat...

Conditions have warmed over most of the forecast area as a ridge
axis moves over the region. Besides snow over the mountains, most
of the region was free from precipitation. Strong downslope
conditions have scoured out the arctic air mass from most
locations in eastern Montana. With the precipitation diminishing,
and temperatures warming, we canceled the freezing rian advisory.
Even with the cancellation, left a slight mention of freezing
rain in the forecast as ground temperatures are still near or
below freezing, and lower valleys in eastern Montana could
certainty see some light freezing rain if any precipitation
redevelops tonight.

Strong mid-level winds around 50 to 60 kts and continued pressure
falls over the lower elevations have strengthened the pressure
gradient over our western zones and thus we have seen an increase
in winds today. Wind gusts have neared 70 mph this afternoon in
Livingston. As conditions warm further east towards Big Timber and
north towards Harlowton, mixing has allowed the higher winds
above the surface to mix down and increase the winds there. The
strongest winds are still expected this evening and tonight in
Livingston, Big Timber, and Beartooth Foothills near Nye as the
strongest mid level winds, and strongest pressure gradients, will
be place across these areas. We expect routine wind gusts from 55
to 65 miles per hour with occasional wind gusts reaching 75 mph.
Further north in Harlowton, the strongest wind gusts will be this
afternoon and early tonight with occasional wind gusts nearing 60
mph. By early Friday morning, pressure falls will stop, and the
strong mid-level winds will begin to subside so the strong winds
should begin to lessen below 60 mph.

As the dangerous winds lessen on Friday morning, westerly flow
will still prevail over the region, along with mountain snow and
warm temperatures. Conditions will remain breezy across the
region, but we do not expect any highlight level winds with the
strongest gusts being around 35 to 45 mph in Livingston and nearby
foothills, and around 25 to 35 in the Plains.

As we move into Saturday a strong shortwave will quickly pass
through the region and bring cooler temperatures for the weekend.
At this point we could see a quick chance for snow but
accumulations appear light at this time. Dobbs.

...Hydrology Concerns...
With the warm conditions in place we are expecting some snow melt
across the area to continue through Friday evening. Significant
ice jam flooding is not expected, but some isolated minor flooding
is possible due to snow melt on frozen ground. This could cause
some minor issues with water on the roadways, but at this time,
widespread flooding is not expected. Dobbs/Chambers

.LONG TERM...valid for Sun...Mon...Tue...Wed...Thu...

Dry weather will prevail through the long term as an upper level
ridge settles in over the Northern Rockies. Pulses of downsloping
winds can be expected with weak bouts of lee-side troughing from
time to time. Temperatures will be near to about 5 degrees above
normal for this time of year. Some uncertainty exists with the
temperature forecast as they may be held back a bit by existing
snow cover and evaporative surface cooling. STP

&&

.AVIATION...

Showers will continue overnight over the Absaroka/Beartooth Ranges
as well as the Crazy Mtns producing obscurations. Elsewhere, VFR
will prevail. High winds in the KLVM vicinity will gradually
decrease overnight. Low to mid level wind speed shear of about
40kts should be expected over most routes. BT

&&

.PRELIMINARY POINT TEMP/POPS...

    Fri     Sat     Sun     Mon     Tue     Wed     Thu
-----------------------------------------------------------
BIL 037/046 027/038 018/037 023/041 023/041 026/044 028/043
    11/B    13/W    10/U    00/U    00/U    10/U    00/U
LVM 042/049 028/035 015/039 022/043 023/044 025/047 026/046
    33/W    24/J    10/N    00/N    00/U    11/B    00/N
HDN 033/046 023/038 010/037 016/039 016/041 018/042 020/041
    11/B    13/W    10/U    00/U    00/U    10/U    00/U
MLS 032/042 027/037 017/035 022/038 020/039 022/041 024/041
    10/B    11/B    10/U    00/U    00/U    00/U    00/U
4BQ 032/045 026/039 015/038 019/040 018/041 021/042 023/043
    01/E    23/W    10/U    00/U    00/U    00/U    00/U
BHK 033/042 027/037 016/034 020/037 019/037 020/039 022/039
    10/B    12/W    10/U    00/U    00/U    00/U    00/U
SHR 033/046 024/036 012/037 015/040 016/043 021/044 020/044
    01/B    23/W    20/U    00/U    00/U    10/U    00/U

&&

.BYZ WATCHES/WARNINGS/ADVISORIES...
MT...High Wind Warning in effect until 5 AM MST Friday FOR ZONES
      65-66.
WY...None.

&&

weather.gov/billings