100
FXUS65 KBYZ 181232
AFDBYZ

Area Forecast Discussion...Updated
National Weather Service Billings MT
632 AM MDT Wed Sep 18 2024

.UPDATE...
A Wind Advisory was added for the Livingston area for current and
potential gusts to 60 mph. Lower confidence exists in the
persistence of these higher gusts compared to surrounding zones
as the overall pattern doesn`t favor continuous higher gusts. TS

.DISCUSSION...

Today through Thursday night...

Earlier this evening a wave pushed through southeast MT bringing
light precipitation and strong surface winds brought down from the
low levels. Currently, the upper level low is over south- central
MT and north- central WY bringing dry slotting to the east, while
the central and western zones are receiving light to moderate
rainfall. As this low slowly lifts north and east, CAMs have
precipitation spreading east through the day and letting up into
the overnight hours. Areas that have at least at least an
additional inch of precipitation are generally west of Rosebud Co.
Higher foothills and mountains north and west of Billings have at
least a 50% chance of 2 inches.

Biggest concern for this forecast is the strong winds. Winds in
the lower levels of the atmosphere (50-60 mph) are predicted to
reach the surface through the day today across much of the region.
One thing that makes this forecast difficult is the opposing
force of the ascent. Given the strong dynamics and placement of
the low over south-central MT as well as the strong low level
winds, this increased confidence in a high wind event. With this,
a High Wind Warning had been issued for much of south-central MT.
There is a possibility this could be extended eastward as low
level winds shift north and east and subsidence sets in over SE
MT. Will be something to reassess later today.

With regards to snow today, freezing levels are forecasted to get
down to around 9000 ft. Higher elevations (10,000 ft+) could see
12-18 inches of snow through this evening. With this, a Winter
Storm warning has been issued for the Beartooth Absaroka
Mountains. Localized areas as low as 7500 ft could see a few
inches through the early morning. Use caution if you have outdoor
or travel plans in the high country.

High temperatures will be in the 50s and 60s today. For Thursday,
dry and warmer conditions will dominate as westerly low takes
place. Highs will be in the 60s and 70s. TS


Friday through Tuesday...

Pacific flow w/ near normal heights will persist Friday thru
Monday. The general consensus among ensembles leans toward this
being a mostly dry period of weather, but there is some
uncertainty here. There are a couple of shortwaves embedded within
the flow. The first Friday and Friday night may bring some showers
(20-30% chance) along with a brief push of modest cold advection.
The second wave Sunday night and Monday may do the same. That
said, there are a few ensemble members (the least probable of
cluster analyses) that show one or both of these waves being
sharper and a bit wetter. Temperatures should be more or less
seasonable (highs in 60s & 70s) for the third week of September.

There is some confidence in a building ridge, and thus warmer and
drier conditions, toward the middle of next week. We could see
temps back near 80F.

JKL

&&

.AVIATION...

There will be widespread impacts to aviation today. Rain and
strong west winds will impact the region today. Heaviest precip
will be west of Rosebud County, and reductions to MVFR are likely.
A few embedded thunderstorms are possible. Strongest winds (gusts
of 40-55 knots) are expected from KBIL westward. Mountains will
be frequently obscured, with snow above 9,500 feet. Precipitation
and wind will gradually diminish tonight as the dynamic weather
system begins to depart to the northeast. JKL

&&

.PRELIMINARY POINT TEMP/POPS...

    Tdy Thu     Fri     Sat     Sun     Mon     Tue
-------------------------------------------------------
BIL 061 053/074 050/075 046/065 044/070 047/070 048/073
    +/T 60/U    01/U    31/B    11/U    12/W    21/U
LVM 060 044/072 042/073 039/065 038/070 041/068 041/072
    +/T 50/U    01/B    21/B    11/U    13/W    21/U
HDN 061 052/075 046/077 044/067 042/071 043/070 045/073
    +/T 70/B    01/U    31/B    11/U    12/W    21/U
MLS 064 055/072 049/076 046/064 044/068 045/069 046/070
    7/T 71/N    00/U    21/B    11/B    11/B    11/U
4BQ 065 054/072 047/078 045/065 043/067 045/069 045/069
    7/W 50/U    00/U    21/B    11/B    11/B    11/B
BHK 068 051/072 046/078 043/065 041/067 042/068 042/069
    7/T 51/N    00/U    21/B    11/B    11/B    11/B
SHR 069 048/076 043/080 040/066 038/070 038/070 041/072
    8/W 50/U    01/U    31/B    11/U    12/W    21/U

&&

.BYZ WATCHES/WARNINGS/ADVISORIES...
MT...High Wind Warning in effect until 9 PM MDT this evening FOR
      ZONES
      29>31-34-36-42-57-58-63-68-138-141-170-172-173-228-235.
     Wind Advisory in effect until 3 PM MDT this afternoon FOR
      ZONE 65.
     Wind Advisory in effect until 9 PM MDT this evening FOR ZONE
      66.
     Winter Storm Warning in effect until 6 PM MDT this evening
      FOR ZONE 67.
WY...None.

&&

$$
weather.gov/billings