Area Forecast Discussion Issued by NWS Billings, MT
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000
FXUS65 KBYZ 281550
AFDBYZ
Area Forecast Discussion...Updated
National Weather Service Billings MT
950 AM MDT Thu Mar 28 2024
.UPDATE...
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A dynamic cold front, supported by strong forcing/instability
aloft, will move across the forecast area from west to east this
afternoon/evening. Timing into Livingston is around 1pm, Billings
3pm, Sheridan 6pm, Miles City 7pm. This cold front will be
supported by outflow winds from convection along it, and as such
will see the potential for 40 to 50 mph wind gusts with locally
stronger gusts possible. Adjusted forecast to add mention of
thunderstorms based on the latest CAM models, lining up with SPC`s
general thunderstorm outline which is areas generally west of a
Sheridan to Hardin to Forsyth line. Given the low freezing levels
this time of year small hail/graupel will be possible with any
storms along with brief heavy precipitation which may be a mix of
rain/snow. Ahead of the front, forecast in good shape with high
temperatures looking to push into the 50s to low 60s for most
locations. Chambers-- End Changed Discussion --
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.DISCUSSION...
Today through Friday...
Satellite imagery shows a ridge axis over eastern MT and dirty SW
flow in advance of a Pacific coast trof. The main shortwave of
interest (to affect us later today) is moving thru northern CA.
Surface analysis shows a modest lee side trof over central MT.
Latest IDA-LWT gradient is only 6mb, and YNP is not terribly cold,
but nonetheless Livingston flirted with 50 mph through the evening
into the overnight hours, with a peak of 55 mph. Now at 08z we
are seeing gusts starting to decrease, and this trend will
continue thru the morning.
Pre-frontal downslope warming will push temps into the 50s to
lower 60s most places today, with some inhibition possible due to
cloud cover. Pacific cold front is set to arrive in the early
afternoon in our west and mid to late afternoon in the Billings
area (and eastward thereafter). We will see showers along and
behind the front, and there may be enough instability (100-200j/kg
of cape) to produce a few rumbles of thunder, mainly for the west
half of our cwa. The combination of a fropa and convection/steep
lapse rates will produce a brief period of gusty W-NW winds, with
localized 40+ mph gusts. Furthermore, it looks as if wet bulb zero
heights will fall enough to change ptype to wet snow, or a
rain/snow mix, along the western foothills in the late afternoon
& evening. Lower elevation snow accumulation will be an inch or
less, but late day travelers should stay alert for rapid changes
and potentially poor visibility (along with the wind of course).
The Beartooth-Absarokas have picked up a little orographic snow
already - an inch or two at Fisher Creek Snotel over the last
several hours. As lapse rates steepen the snow in the mountains
will turn heavy for a few hours later today and this evening.
Totals for our western mountains should reach 4-8". A nice quick
addition of SWE where it`s really needed.
Shower activity will taper off late tonight. On Friday, with
building lee side pressures and another weaker shortwave emerging
from the SW flow aloft, winds will turn around to an upslope
direction. There is a good (40-50%) chance of rain/snow especially
close to the foothills by Friday afternoon. Expect temps to take
a step down tomorrow with highs in the 40s to around 50F.
Here are a few notable probabilities:
40+ mph wind gusts in our west today: 40%
4" of snow over the western mtns today/tonight: 85%
8" of snow over the western mtns today/tonight: 10%
0.10" of pcpn at lower elevations today/tonight: 40% west of
Rosebud County, 10% east.
JKL
Friday Night through Thursday...
The flow starts of the weekend becoming unsettled as heights
lower due to a system pushing south and east across southern
Canada. Its associated backdoor cold front swings through the area
Friday night, shifting winds to the east and cooling off the
area, with highs for the weekend being 5-10 F degrees below
normal. Some light rain/snow will occur on Saturday, but minimal
impacts are expected from it.
On Sunday, a dynamic trough cuts inward across the southwest
CONUS and brings heavy precipitation to much of the western CONUS.
Southern MT and northern WY stay on the far northern extend of
it, as this upper low looks to stay well south of us, and leaving
it`s ascent down south with it. That said, we do get a surge of
moisture to cut across the area, and combined with some usplope
flow and low-level divergence will bring some rain and snow to the
area. Confidence is increasing for it to stay mostly confined to
the foothills and far southeast MT. While most of the snow will
likely melt within a day of it falling, greatest impacts will be
for travel Sunday evening through Monday morning, especially along
US-212 and I-90 south of Crow Agency. Rain that falls before
switching over to snow could result in icy roads Sunday night as
well. Plan accordingly if you plan to travel along these roads
during this time frame.
High confidence in an upper ridge building back in for the start
of the work week and quickly bring temperatures roaring into the
low 60s by Tuesday afternoon. The mid to latter half of the week
is where uncertainty comes into play again. It`s about a 50/50
split if we stay under ridging on Wednesday and Thursday and keep
the warm and dry conditions, or if we start to re-introduce rain
and snow showers to the area due to some cyclonic flow and
lowering heights about 50% of ensemble members bring want to bring
in.
Vertz
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.AVIATION...
SW wind gusts of 30-40 knots will impact KLVM early today, then
winds will gradually decrease after sunrise. A moist Pacific flow
is producing snow over SW aspects of the Beartooth-Absarokas, and
these mountains will be frequently obscured. VFR will prevail
elsewhere through early afternoon.
A Pacific cold front will bring showers and gusty winds (and
perhaps a few rumbles of thunder) from mid afternoon through the
evening. Local MVFR is possible w/ the shower activity, and
mountains will be obscured in heavier snow. The front is expected
to produce a wind shift to W-NW winds gusting 25-35 mph along the
western foothills and eastward to KBIL. JKL
&&
.PRELIMINARY POINT TEMP/POPS...
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Tdy Fri Sat Sun Mon Tue Wed
-------------------------------------------------------
BIL 060 032/049 029/042 028/044 028/056 033/066 042/064
7/T 63/W 34/O 26/O 31/B 00/U 14/R
LVM 052 028/047 028/043 025/043 026/052 032/062 038/059
9/T 74/W 33/O 24/S 20/B 00/U 13/R
HDN 062 030/051 027/044 027/046 025/055 029/067 037/065
5/T 62/W 24/O 26/O 41/B 00/U 24/R
MLS 057 030/045 025/041 026/042 025/050 028/061 039/061
1/E 50/B 03/O 12/R 21/B 00/U 12/R
4BQ 063 032/048 027/044 028/043 027/048 029/061 039/064
1/B 30/B 14/O 24/O 41/B 00/U 12/R
BHK 050 027/043 021/040 023/039 021/046 024/056 034/060
0/N 51/B 03/O 22/S 21/B 00/U 11/U
SHR 063 030/048 026/044 025/043 026/049 027/061 035/064
2/T 43/W 35/O 47/O 62/S 00/U 13/R-- End Changed Discussion --
&&
.BYZ WATCHES/WARNINGS/ADVISORIES...
MT...None.
WY...None.
&&
$$
weather.gov/billings