Area Forecast Discussion
Issued by NWS Billings, MT

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FXUS65 KBYZ 241548

Area Forecast Discussion
National Weather Service Billings MT
948 AM MDT Sat Mar 24 2018


Relatively minor update this morning to make a few adjustments to
pops and weather.

First, expanded pops a bit further east for the
morning hours to account for current and possible showers through
the remainder of the morning. Areas with increased pops are
Musselshell and Stillwater Counties. Any showers precip that does
reach the ground should be light, with little accumulation, but
think is worth having in grids. Also, expanded pops eastward for
the afternoon period, dragging slight pops to eastern MT border.
Finally, added mention of ISOLD thunder for areas east of
Billings this afternoon/evening. Pretty good instability, laps
rates, and Low Level Jet in place, not to mention strong thermal
gradient developing due to open and snow covered ground. Combine
this with cold front crossing the region, and would be surprised
if we did not see some thunderstorms in the mix. Otherwise the
inherited short term forecast appears in good shape. AAG


.SHORT TERM...valid for Tdy and Sun...

Moisture streaming in from the southwest will bring increasing
shower chances to the western mountains this morning. A couple
inches of snow are possible. A shortwave and associated cold
front will move east through the area this afternoon, spreading
isolated to scattered showers across the plains. Showers look to
linger longest over eastern areas into this evening and night.
Winds will increase across the west this afternoon and early
evening as well with pressure falls to the east. Winds do not
appear to be advisory strength at this time, but will need to
watch closely.

An upper low and associated trough moves onto the West Coast and
east into the Great Basin on Sunday, allowing moisture and energy
to advect into the region. As a result, precipitation chances
increase on Sunday, with a change over from rain to snow expected
Sunday evening as widespread precipitation develops over
southeast Montana and north central Wyoming. Latest model runs
have trended a bit slower with spreading the precipitation north
into Montana Sunday evening, but remain consistent in the overall

High temperatures will range from the 40s and 50s today, to the
40s for most locations on Sunday. Low temperatures in the 20s can
be expected tonight and again Sunday night. We will continue to
monitor streams/rivers for ice jams and potential lowland
flooding. STP

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

Upper shortwave trough should continue to propagate northeastward
over the Northern Rockies during the day on Monday, causing snow
to continue over southeast MT /east and southeast of Billings/ and
north central WY. Models differ on liquid equivalent
precipitation amounts so the snowfall accumulation forecast is
still a bit uncertain at this time. That said, 4 to 8 inches of
snow are possible over southeastern Powder River County, much of
Carter County, and over Sheridan County, WY...with higher amounts
in the Bighorn Mountains. Ground is still snow-covered over SE MT,
so think that these accumulations are achievable away from
pavement. Accumulations on roadways are more likely during the
night...with daytime accumulations more limited to periods with
heavy snowfall rates.

Upper trough should exit the area to the east by Monday evening.
Shortwave ridging behind the trough will bring dry weather to the
region for Monday night and Tuesday. Then the weather turns
unsettled for the rest of the week as weak disturbances move
across the region in northwesterly flow aloft. A surface cold
front looks to meander over the CWA during Wednesday-Friday as
well, which could help to further support some light precipitation
/mainly light snow showers overnight and rain or wet snow showers
during the daytime/ with the coolest air northeast of Billings.

High temperatures will generally be in the 40s and lower 50s
during the work week, with the highest readings in the
Beartooth/Absaroka/Bighorn foothills and the coolest readings in
eastern MT. Temperatures in far SE MT likely will only reach the
lower to middle 30s on Monday under the falling wet snow. RMS


Southwest flow aloft with increasing moisture approaching the
region. Scattered snow showers are possible west of KBIL this
morning. Scattered rain showers are then possible across south
central MT this afternoon. The showers can bring brief MVFR
conditions. Western mountains will be obscured today in clouds and
snow showers. RMS/Borsum



    Tdy Sun     Mon     Tue     Wed     Thu     Fri
BIL 052 028/043 027/043 027/048 032/045 029/046 031/048
    2/W 22/W    33/W    11/U    34/W    43/W    31/E
LVM 050 025/042 023/043 025/050 032/048 030/049 032/052
    7/W 34/W    31/B    11/N    45/W    42/W    21/N
HDN 048 026/041 025/042 022/047 030/045 026/046 026/047
    3/T 32/W    43/W    10/U    44/W    43/W    22/W
MLS 046 027/041 027/040 024/045 030/040 025/040 025/042
    2/W 41/B    24/W    10/U    33/W    32/W    32/W
4BQ 049 027/041 026/038 020/043 029/043 023/042 025/045
    2/T 32/J    88/W    10/U    33/W    33/W    22/W
BHK 042 027/041 026/036 021/041 027/038 021/037 020/038
    2/W 31/B    26/W    10/U    32/W    13/W    22/W
SHR 058 029/043 025/039 020/046 028/044 026/045 027/049
    2/T 34/W    86/W    10/U    44/W    42/W    22/W


MT...Winter Storm Watch in effect from Sunday afternoon through
      Monday afternoon FOR ZONES 32-33-36>38-58.
WY...Winter Storm Watch in effect from Sunday afternoon through
      Monday afternoon FOR ZONES 98-99.


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