Area Forecast Discussion
Issued by NWS Billings, MT

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FXUS65 KBYZ 191517

Area Forecast Discussion
National Weather Service Billings MT
917 AM MDT Mon Mar 19 2018

Snow has ended in our far east as shortwave exits to the central
plains. An area of low clouds with some fog remains across our
eastern cwa, and have extended mention of fog til midday.
Otherwise, we will remain under below normal heights today with a
weak trof over northwest MT. This trof will swing east today, and
the combination of weak synoptic forcing and diurnal instability
under cold pool aloft will bring the potential for rain/snow
showers this afternoon and evening, mainly across our west/central
areas. PV will track east overnight and there is a good chance of
snow showers from Miles City to Baker and Ekalaka late tonight
into early Tuesday. With the instability (showalters near +1C),
could see local accumulation to an inch.

For the update have adjusted pops to account for a bit more
coverage late this afternoon and evening, again per the
instability. Have also made minor adjustments to temps and winds.
Highs today should reach the mid-upper 40s in our west, but will
linger in the 30s to our east.

Today will be the 33rd consecutive day with a below normal average
temp at Miles City.



.SHORT TERM...valid for Tdy and Tue...

Area of upper divergence and differential vorticity across our far
eastern zones early this morning produced some good radar returns
along the Dakota border per Bowman Radar. However, the bulk of
this has moved over the border and any additional impacts to
Fallon and Carter look minimal. Thus we have opted to cancel the
Winter Weather Advisories.

Another shortwave will cross the region tonight into early Tuesday,
bringing another shot of ISOLD/SCT precip. This feature continues
to look weak with limited moisture. The best chance of any
measurable precipitation is over the mountains and nearby
foothills, and perhaps over Fallon county which catches the best
height falls and lift related to the short wave.

Some instability lingers across our Absaroka/Beartooth mountains
into Tuesday afternoon. So will keep a slight chance of snow
showers going there, but otherwise things look mostly dry for
late Tuesday/Tuesday night as high pressure gradually builds over
the region.

Temps will be trending up, but generally remain under seasonal
averages through Tuesday. BT

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

A ridge of high pressure will control the weather pattern through
the end of work week and keep most of the lower elevations,
outside the mountain foothills, dry through Thursday afternoon.
Expect frequent mountain snow showers through the period as Pacific
moisture works its way into the mountains. As for temperatures,
expect warmer conditions in place but temperatures will still
remain around or just above seasonal values and in the low to mid
50s in and west of Billings/Sheridan/Roundup. East of
Billings/Sheridan/Roundup, an east wind through much of the
period will limit the warmup and likely keep many of these
locations in the 40s through the rest of the week.

By Friday, and into the weekend, the ridge gets broken down by
several disturbances which will produce unsettled conditions.
There is good agreement that a disturbance will pass through the
region Friday afternoon giving much of the area a chance for rain
and snow showers. Will have to watch for hydrology concerns by the
end of the week as the snow melt from the warmer temperatures,
combined with some additional precip could produce a few ice jams
as river and stream flows increase. Could see a brief break in the
precipitation on Saturday before another system moves in Sunday,
but as of now the details are limited so just left a chance for
rain and snow showers through the remainder of the weekend, and
into the start of next week. Dobbs



VFR should prevail at most south central MT and north central WY
terminals today. Isolated to scattered rain or snow showers with
brief MVFR conditions are possible this afternoon from around
KRPX-KBIL-KSHR and west. Farther east, near KBHK, LIFR/IFR
conditions this morning should continue into the afternoon with
periods of MVFR conditions possible. MVFR/IFR can return to more
terminals east of KBIL, including KMLS, later tonight. Areas of
mountain obscuration will continue through the TAF period. RMS



    Tdy Tue     Wed     Thu     Fri     Sat     Sun
BIL 044 027/047 029/048 030/050 032/048 029/046 027/043
    2/W 20/U    00/B    12/W    32/W    13/W    32/W
LVM 046 028/049 029/052 032/057 033/051 028/045 025/042
    3/W 20/N    02/W    14/W    42/W    23/W    32/W
HDN 045 025/049 025/050 027/049 029/047 025/046 023/042
    2/W 20/U    00/B    12/J    32/W    13/W    32/J
MLS 035 023/039 021/040 025/041 029/041 023/041 023/038
    1/E 31/B    00/U    01/B    43/W    13/W    42/W
4BQ 037 020/044 022/047 026/047 031/047 025/046 023/040
    1/E 10/B    00/U    01/B    42/W    23/W    33/W
BHK 032 020/036 018/040 024/040 029/040 024/040 022/036
    1/E 32/S    00/U    00/B    64/J    22/W    43/J
SHR 042 022/047 022/050 028/053 033/050 027/048 024/042
    2/W 20/B    00/B    12/W    24/W    22/W    32/W




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