High Wind in Montana, November 27, 2018

Area Forecast Discussion...Updated
National Weather Service Billings MT
857 PM MST Mon Nov 26 2018

.UPDATE...
Winds have already gusted to 64 mph at Livingston. This wind
speed a little earlier than forecast, so bumped winds for this
evening. Also, area of stratus firmly entrenched over far
southeast. Latest high resolution guidance keeps it in there for
the entire night. Adjusted sky grids for the entire area to better
reflect current satellite imagery and observations. Temperatures
will be held up due to cloud cover and adjusted hourly
temperatures to reflect this, as temperatures have not cooled
quite as aggressively as forecast this evening. TWH

&&

.SHORT TERM...valid for Tue and Wed...

Upper level ridge over western Montana will slowly weaken and
shift east tonight through Tuesday. Movement of the ridge being
driving by a strong southwest flow into the Pacific Northwest
which is helping induce leeside troughing over the Canadian
Rockies. This upstream flow moves into western Montana by late on
Tuesday and eventually pushes a Pacific cold front across the area
Tuesday evening.

Pattern is mainly dry for tonight through Tuesday shower activity
will be increasing over the mountains. Frontal passage and weak
shortwave will increase chance for showers Tuesday night and could
be a mix of rain or snow but significant snowfall not expected.

Main overnight story into Tuesday evening is the winds supported
by the leeside troughing over Canada and surface high pressure
over eastern Idaho western Wyoming. Winds aloft are northwesterly
early tonight trending westerly late tonight and becoming
southwesterly Tuesday afternoon briefly ahead of the front. This
will support 40 to 60 mph winds in the gap flow areas with
increasing winds Tuesday afternoon as they spread eastward as a
prefrontal trough moves through the area. Frontal passage expected
early Tuesday evening which will bring an end to the windier
period.

Wednesday airmass dries out a bit Wednesday over northern Montana
as a downslope westerly flow develops but a bit of divergence
aloft develops along the Montana Wyoming border Wednesday
afternoon in response to a strong jet moving through northern
Utah. This will support some precipitation over northern Wyoming
and southern portions of southeast Montana.

Temperatures will be 10 degrees above normal the next couple of
days due to favorable mixing and many areas will be in the 50s.
borsum

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

Medium range models are suggesting a split flow pattern across the
western CONUS after midweek. A trough or upper low is progged to
move through the Great Basin area of Nevada while troughiness
persists off the NW Pacific coast. In the meantime, we have a
short wave ridge over our region. Eventually, a series of short
wave troughs work into the inter-Rockies Friday and into the
weekend bringing Pacific moisture into our region. This will lead
to unsettled and seasonably cool weather for the latter part of
the week. All the energy moving through leads to a broad upper
trough and cyclonic pattern over the Rockies and high plains.

One item of special note...The 12Z deterministic ECMWF shows a
substantial precipitation event for our CWA late Friday and into
the weekend with a powerful upper low developing over Nebraska.
But this model has jumped around quite a bit over the last few
cycles so we are not inclined to lean much on it at this time.

Bottom line is the extended period will trend cooler and
unsettled through the weekend and into early next week. Persistent
snow showers at times are a good bet with accumulations possible,
especially in the foothills, but we do not yet see much evidence
of an organized system shaping up. Highs in the upper 20s and 30s
are expected, but pattern may open the door for much colder air
at some point next week.

For this package we have not made any significant changes in the
extended, but did cool off Sunday and Monday of next week. BT

&&

.AVIATION...

An area of low clouds will produce IFR conditions close to the
Dakotas border tonight through around 15z Tuesday, impacting KBHK
and locations east of K4BQ. VFR will prevail otherwise with
periods of mainly mid and high clouds. Mountains will be
occasionally obscured in scattered light rain/snow showers
Tuesday. Strong SW winds will persist at KLVM over the next 24
hours with frequent gusts of 40-55 kts. JKL

&&

.PRELIMINARY POINT TEMP/POPS...

    Tue     Wed     Thu     Fri     Sat     Sun     Mon
-----------------------------------------------------------
BIL 031/050 037/049 030/046 027/042 026/039 023/033 020/031
    10/N    32/W    10/U    02/W    32/W    23/J    32/J
LVM 030/047 034/044 027/043 026/039 022/036 019/030 017/028
    11/N    32/W    11/B    12/W    32/J    22/J    22/J
HDN 025/051 032/051 026/050 023/044 024/041 020/032 019/032
    10/B    33/J    10/U    02/W    32/W    23/J    33/J
MLS 023/049 034/051 029/049 025/043 025/038 021/031 019/029
    11/E    22/W    10/U    02/W    33/W    23/J    32/J
4BQ 027/051 035/050 029/050 023/044 025/039 020/031 017/029
    11/B    22/W    00/U    02/W    33/W    23/J    33/J
BHK 019/044 032/049 029/046 023/041 023/035 018/029 016/027
    01/E    21/B    10/U    02/W    34/J    33/J    32/J
SHR 024/049 030/046 024/046 020/040 023/037 016/030 016/029
    10/B    24/W    10/U    02/W    32/J    23/J    33/J

&&

.BYZ WATCHES/WARNINGS/ADVISORIES...
MT...Wind Advisory in effect until 1 AM MST Wednesday FOR ZONES
      65-66.
WY...None.

&&

weather.gov/billings

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE BILLINGS MT
1149 PM MST MON NOV 26 2018

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

1039 PM     NON-TSTM WND GST 6 ENE LIVINGSTON        45.70N 110.45W
11/26/2018  M58.00 MPH       PARK               MT   ASOS

&&

RMS

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE BILLINGS MT
306 AM MST TUE NOV 27 2018

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0248 AM     NON-TSTM WND GST 6 ENE LIVINGSTON        45.70N 110.45W
11/27/2018  M55.00 MPH       PARK               MT   ASOS

&&

RMS