Area Forecast Discussion
Issued by NWS Billings, MT

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125
FXUS65 KBYZ 010826
AFDBYZ

Area Forecast Discussion
National Weather Service Billings MT
226 AM MDT Wed May 1 2024

.DISCUSSION...

Today through Thursday...

Cyclonic flow associated with upper low to our north and below
normal heights will keep our area chilly through Thursday, w/
occasional rounds of mainly light precipitation. Mountains will
see a few more inches of snow, while snow levels are sufficiently
low to produce periodic wet snow showers along the foothills. It
should be noted that it has been snowing at Roscoe Hill and Red
Lodge over the past few hours, with a little accumulation on the
grass.

Satellite imagery shows an upstream PV max moving eastward thru
southcentral MT, and this feature is responsible for the area of
rain/snow from the Beartooth-Absarokas to near Billings, and just
recently we are starting to echoes form over the Pryors and
southern Bighorn County. Much of the region will see some light
showers around today, but with boundary layer winds turning to the
NW our southern upslope areas should be the "wettest" (0.15" or
less). Places like Pryor, Dayton and Sheridan could see a little
wet snow at times. Otherwise, it will be seasonably chilly today
with highs in the upper 40s to mid 50s. Winds will be breezy along
the western foothills (but much lighter than Tuesday).

Look for a period of drying tonight as the aforementioned wave
passes and downslope winds prevail. In fact, gusts from Big Timber
to Harlowton should see gusts increase to 30-40 mph late tonight
into Thursday as gradients tighten in response to the next wave
from the northwest.

Upper low drifting to southern SK and Pacific jet anchored well
to our south will allow for trowal moisture to wrap southward in
some fashion late tonight and Thursday. There is some uncertainty
here. Consensus suggests flow aloft will be too westerly for
anything more than light precip to reach our cwa on Thursday, and
most of that should be over our eastern cwa as western parts will
remain downsloped. That said, the lower air mass will remain
unstable and it is possible that some of the higher hills in our
east (Hysham Hills, Lame Deer Divide, Government Hill) could see a
little wet snowfall, especially early in the day when models show
850mb temps advecting to near 0C. Something to watch. Overall,
ptype will be a mix of rain & snow, and surface temps will likely
be too warm to produce much of a travel impact other than locally
reduced visibility where it does snow. Mixed NW winds will be
breezy as well on Thursday (20-30 mph gusts). Expect temps in the
mid 40s to mid 50s.

Over the next 36 hours, mountain locations have a 60% chance of
seeing 3" of snow, and a 25% of 6". These probabilities are
greatest over the Crazy Mountains which will be favored when the
NW flow trowal arrives. There is a 40% chance of 1" of snow along
the foothills.

JKL

Thursday night through Tuesday...

Cyclonic flow over northeast MT will slowly move northeast,
keeping most of the region in low PoPs (35% or less for lower
elevations) through Friday. Any precip that falls will likely be
less than a tenth of an inch. Friday night into Saturday, ridging
builds in for the weekend allowing for above average temperatures
and dry conditions. Sometime Sunday night into Monday, ensembles
depict a Pacific low tracking east, likely to providing unsettled
weather and increased chances for precipitation. The track and
timing of this system is uncertain at this time and there is much
spread in precip amounts between ensembles. If forcing comes in
place to favor our region, this and above normal precipitable
water values will bring beneficial moisture to the region. The
probability for half an inch of precip Mon-Tues is around 25-35%
for the region. The mountains will likely get a few inches of snow
above 6000-7000 ft during this same period.

High temperatures will be in the 50s Friday, 60s to low 70s
Saturday, 60s to low 80s Sunday and 60s for the remainder of the
period. TS

&&

.AVIATION...

Mostly light rain/snow showers near the foothills will produce
local MVFR today into this evening, possibly impacting KLVM & KSHR
at times. Mountains will be frequently obscured. VFR should
prevail north and east of the foothills (i.e. KBIl to KMLS &
KBHK), though there will be areas of light precip and mid level
clouds. W-NW winds will gust 15-25kts along the western foothills,
otherwise winds will be much lighter than Tuesday.

Tonight, much of the region will see drying, but areas of light
snow/rain will spread over the NW (invof KHWQ) after midnight.
Westerly gusts of 20-30kts will impact the western foothills
tonight.

JKL

&&

.PRELIMINARY POINT TEMP/POPS...

    Tdy Thu     Fri     Sat     Sun     Mon     Tue
-------------------------------------------------------
BIL 052 035/053 034/054 033/068 044/077 047/068 042/063
    5/W 25/W    34/W    00/B    03/T    45/W    33/W
LVM 048 029/050 030/053 030/065 041/068 041/062 037/059
    5/W 26/W    34/W    01/B    15/T    55/W    34/W
HDN 054 031/055 031/055 030/071 043/083 047/069 041/064
    5/W 26/W    33/W    10/U    02/T    45/W    33/W
MLS 054 033/053 033/052 030/067 044/081 051/070 044/066
    2/W 26/W    32/W    00/U    01/B    34/W    43/W
4BQ 055 031/055 031/053 029/069 046/083 049/070 042/064
    3/W 34/W    22/W    00/U    01/B    34/W    33/W
BHK 055 031/053 030/050 028/062 039/077 049/069 040/063
    2/W 35/W    23/W    10/U    01/N    35/W    43/W
SHR 052 026/053 027/052 028/068 041/080 043/065 037/063
    7/W 55/W    35/W    10/U    02/T    45/W    33/W

&&

.BYZ WATCHES/WARNINGS/ADVISORIES...
MT...None.
WY...None.

&&

$$
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