Area Forecast Discussion
Issued by NWS Billings, MT

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831
FXUS65 KBYZ 230309
AFDBYZ

Area Forecast Discussion
National Weather Service Billings MT
909 PM MDT Fri Sep 22 2017

.UPDATE...

Looking at recent upper level and radar trends, shifted the
highest POPs and rain amounts east into Big Horn and Southern
Rosebud county overnight as forcing for showers is further east
than previously forecast as it moves north from Wyoming.
Otherwise, much of the previous discussion remains valid.

Rain coverage (and snow in the higher elevations) is beginning to
develop and will continue to do so through the next few hours. By
3am the forcing will begin exiting north out of the region and
showers will begin to slowly dissipate. With this overnight rain,
can`t rule out some snow mixing-in in the lower elevations, but
any snow will likely be confined to the very high hills and along
foothill regions. Accumulations away from the foothills are not
expected aside from a possible dusting on the higher hills. Dobbs

&&

.SHORT TERM...valid for Sat and Sun...

Upper low centered over southwest Idaho this afternoon will
continue to transport moisture and energy over the region this
evening and overnight. Precipitation will increase over central
and western areas again this evening and spread north. Up to 0.40
inches of liquid precipitation can be expected with a few inches
of snow over the mountains and an inch or two along the foothills,
mainly near Red Lodge. Have continued the Winter Storm Warnings
for our western mountains through late tonight to account for the
next round of expected precipitation. Other locations out onto the
plains may see snow mix in later this evening and overnight with
a dusting on grassy surfaces possible. Will need to monitor for
fog potential overnight given the recent precipitation.

Showers will persist into Saturday as the aforementioned upper low
drops into the Great Basin region and continues to send waves of
energy through the area. Steadier precipitation develops during
the afternoon over eastern areas on Saturday as energy and
diffluence aloft increase over eastern Montana and into the
Dakotas. The upper low will slowly move north and east into
Wyoming on Sunday, continuing to generate periods of showers.
Best chances being for areas generally east of Billings. Rainfall
totals up to 0.50 inches are possible from Saturday through
Sunday, highest near the Dakota borders.

Below normal temperatures will persist through the short term with
highs in the 40s to 50s and lows at night in the lower 30s to 40s.
STP


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


A nice fall week ahead after the weekend cold/showers. Trof will
slowly push east Monday into Tuesday allowing drier west to
northwest flow to filter into the area. This will begin to dry out
the area from west to east and boost temperatures back into the
60s Tuesday afternoon. Heights continue to build through the week
with 586dm by Friday afternoon. Expect Thursday and Friday
temperatures near seasonal levels, around 70 degrees for the
Billings area. Building heights should keep conditions dry
Wednesday through Friday. Chambers
&&

.AVIATION...


Expect showers to continue mainly from Billings and Sheridan east,
with stratus and possible fog development due to the recent
precipitation and cold upslope surface winds. Conditions will
continue to be MVFR/IFR at most locations, with areas of
LIFR/VLIFR from around Billings south into the Sheridan vicinity.
Precipitation will turn to drizzle/flurries before sunrise but
expect poor flight conditions to persist into the mid/late morning
period Saturday. Conditions should improve during the afternoon,
but precipitation will linger across southeast Montana.
Chambers/Reimer

&&

.PRELIMINARY POINT TEMP/POPS...

    Sat     Sun     Mon     Tue     Wed     Thu     Fri
-----------------------------------------------------------
BIL 037/048 038/050 038/057 040/061 043/064 043/067 041/069
    83/W    33/W    32/W    11/B    11/B    11/U    00/U
LVM 031/048 031/049 032/055 035/057 037/061 036/065 037/070
    32/W    22/W    21/B    11/B    11/B    11/U    00/U
HDN 039/051 039/051 037/058 037/063 040/064 040/068 039/071
    84/W    44/W    32/W    11/B    11/B    11/U    10/U
MLS 038/051 040/051 038/055 038/062 041/064 041/066 039/069
    35/W    54/W    32/W    11/B    11/B    11/U    00/U
4BQ 039/046 039/048 037/050 037/059 038/062 039/064 037/067
    78/W    86/W    44/W    21/B    11/B    11/U    10/U
BHK 039/048 040/049 037/053 038/059 039/062 040/064 038/067
    48/W    85/W    33/W    21/B    11/B    11/U    10/U
SHR 036/044 035/045 034/051 033/058 036/060 036/064 035/067
    76/W    65/W    44/W    21/B    11/B    11/U    10/U

&&

.BYZ WATCHES/WARNINGS/ADVISORIES...
MT...Winter Storm Warning in effect until 6 AM MDT Saturday FOR
      ZONES 67-68.
WY...None.

&&

$$
weather.gov/billings



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