Area Forecast Discussion
Issued by NWS Billings, MT

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FXUS65 KBYZ 230330

Area Forecast Discussion
National Weather Service Billings MT
830 PM MST Thu Feb 22 2018

Water vapor and H5 analysis shows troffing/low heights across the
region, with Pacific NW shortwave digging to the Great Basin.
There is enough mid level moisture and instability to produce some
snow showers over our western mountains tonight, but that`s about
all. Our western lower elevations should remain dry (w/ some cloud
cover), and have adjusted pops accordingly. It will of course be
another cold night as weak reinforcing Canadian surface high
settles over eastern MT. Miles City, after a high of only 2 above,
has already fallen to 8 below, and coop reports at Hysham and
Brandenberg show temps below zero earlier this evening. Have
dropped expected low temps across our eastern valleys, where 20
below will be approached again. Miles City`s record low of 18
below on the 23rd will be challenged. Tomorrow will be continued
dry with high temps slightly warmer than today...which is to say
well below normal. JKL


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

Overall a quiet couple days in store across the forecast area
snow-wise but winds will begin to pick up along with increasing
chances for blowing and drifting snow. A weak cold front will drop
into the area by this evening allowing for winds to switch to a
northeasterly direction. However, these should be light so we are
not anticipating any blowing/drifting snow issues. High level
clouds will increase across the forecast area and these should
help temperatures to not drop as cold as the past 3 nights. Most
locations will drop below zero once again with the coldest
readings east of Billings. A few snow showers will be possible for
the Beartooth/Absaroka Mountains and foothills. Otherwise, no
snow is expected overnight.

A large upper low and trough will carve out across the four
corners region Friday and into the southern and central plains on
Saturday. This will bring a split flow aloft across our forecast
area Friday and a westerly flow aloft Saturday into Saturday
night. A few weak disturbances will move over the area but nothing
organized at this point. These disturbances will bring continued
chances for some mountain and adjacent foothills snow showers.

The main impact in the short term will be the return for strong
gusty winds for the Upper Yellowstone and Stillwater Valleys
Friday night into Saturday morning. Lee-side troughing will set up
along with tighter pressure gradients. Wind guidance shows the
possibility for advisory winds for the Livingston to Nye area
during this time, however, probabilities are not overly high. As a
result, we will hold off on issuing any wind advisories for those
areas at this time. These strong gusty winds will cause areas of
blowing and drifting snow from Billings and areas westward,
especially for areas prone to drifting. Temperatures will continue
to moderate with lower to middle 20s Friday, except far southeast
Montana will stay in the teens. For Saturday, most areas will see
upper 20s to lower 30s. Hooley

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

Several changes to the long term forecast this afternoon, with
models in relatively good agreement through the bulk of the
extended forecast period. The overall forecast for the extended
period looks like mainly dry conditions across the plains, with
mountain snows, and periods of gusty winds, especially in the
west. The concern over a large weather system crashing through the
region mid is a thing of the past, if current model runs hold
true, with potential system progged into the region some time next

A weak shortwave will complete passage through the region Sunday
morning, ushering in shortwave ridging for Sunday. A weak cold
front will move quickly into the region Sunday evening/night,
flattening the ridge, and brings our best chance for any
snow into the plains for the duration of the extended period, but
accumulations outside the mountains and near foothills looks
fairly minimal at this time. This front clears on Tuesday
morning, with a bringing dry northwest flow over the region, which
quickly transitions to zonal flow by Wednesday morning. This
should coincide with a period of strong gusty winds in the west
as downslope flow develops. Advisory strength (58mph) gusts are
possible around KLVM. Mainly zonal flow gives way to a developing
upper level ridge by Thursday morning, which persists into the
weekend. Through the period it appears that Pacific flow will
continue to stream in western mountains, resulting in at least
some periods of mountain snow. mountain

As for temperatures, expect to see highs around freezing each
day, with lows in the single digits to teens above zero. AAG



VFR conditions will prevail through the TAF period, with
continued potential for isolated to scattered mountain snow
showers, resulting occasional mountain obscurations. AAG



    Fri     Sat     Sun     Mon     Tue     Wed     Thu
BIL 906/022 009/033 012/034 019/034 013/033 012/034 015/033
    00/U    01/B    22/S    22/S    22/S    22/J    11/B
LVM 904/024 015/029 015/032 022/033 013/035 014/035 018/036
    11/N    14/S    42/S    34/S    32/S    22/J    22/J
HDN 913/021 001/030 006/032 016/033 011/031 008/031 011/032
    00/U    01/B    22/S    22/S    22/S    21/B    11/B
MLS 917/008 001/028 011/029 014/030 007/026 005/027 009/026
    00/U    01/B    21/B    12/S    11/B    11/B    11/B
4BQ 913/016 003/027 008/029 015/033 010/030 008/030 010/031
    00/U    10/B    11/B    12/S    21/B    11/B    11/B
BHK 911/016 002/028 011/027 013/031 008/027 005/027 008/028
    00/U    11/B    21/B    11/B    11/B    11/B    11/B
SHR 910/023 004/032 009/031 012/033 010/032 008/033 011/034
    00/B    01/B    22/S    12/S    22/S    21/B    11/B




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