Area Forecast Discussion
Issued by NWS Billings, MT

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FXUS65 KBYZ 161532
AFDBYZ

Area Forecast Discussion
National Weather Service Billings MT
932 AM MDT Sat Sep 16 2017

.UPDATE...

Only update needed was to cancel the winter storm warning over the
Bighorn mountains in Wyoming. With warming temperatures, lighter
rain/snow, and good road conditions, believe winter storm
conditions are no longer occuring there. The highest elevations
of the Bighorns will continue to see isolated rain/snow showers
through the rest of the afternoon. These conditions could cause
minor difficulties through the remainder of the morning and early
afternoon.

Conditions still should dry out from west to east beginning later
this afternoon. Dobbs

&&

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

Water vapor imagery shows slowly-evolving trof over the region,
with one shortwave having departed to the northeast, another
centered near Malad (ID) and a third dropping southward on the
back side of the trof in central ID. Precipitation has become
lighter and with less coverage, but we aren`t quite through yet.
Ascent with passage of upper trof will bring another period of
precipitation from west to east from this morning into the
afternoon, then descent takes over as heights begin to rise from
the west. Have adjusted pops to show a decreasing trend through
the day. Our western parts will in all likelihood dry out by mid
afternoon, and our east by sunset. Beartooth Pass remains closed
and will make no changes to winter highlights in effect for the
Crazy, Beartooth, Absaroka and Bighorn Mountains. We recently
received a report of snow falling in Gardiner, and current temps
suggest some wet snow at places like Nye and Red Lodge, but the
deep upslope and strong forcing have faded so no need to issue any
additional highlights for the foothills. That being said, any
early morning travelers will want to use caution over places like
Bozeman Pass and Roscoe Hill.

Clearing skies and light winds associated with surface high, and
little boundary layer drying, will result in a good chance of fog
tonight. With low temps in the 30s we will also likely see some
frost. For much of the cwa tonight will be the coolest night we
have seen since last spring.

Today will again be much cooler than normal with high temps in
the upper 40s to lower 50s. Warming/drying trend begins Sunday
with temps back to the 60s.

JKL

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

Weak upper ridging early Monday will give way to cyclonic flow by
Monday evening. Expect temps to be a little above normal for
central and eastern zones Monday. Some eastern locations should
climb back to 80F on Monday, before temps drop once again.

A deep Pacific low will move into the region Monday night,
introducing cyclonic flow over the region. Models continue to be a
bit out of phase, but generally agree on unsettled cyclonic flow
dominating the remainder of the extended forecast period. This
will result in temps 10 to 15 degrees below normal for the
remainder of the extended period.

Best agreement is early in the period with the low and associated
cold front will bring a good chance of showers to the area into
Tuesday. A period of windy conditions is expected behind the cold
front Monday night. Models begin to diverge here, with pieces of
energy crossing the region at different times. Have continued
with, but slightly expanded, broadbrush type pops through the
remainder of the period. Expect rain across plains, but mountains
will likely see rain/snow showers as 700mb temps remain below
zero.

Anyone with outdoor plans in the high country next week should be
prepared for the cold.

AAG

&&

.AVIATION...

Light rain and high elevation snow will persist across the region
this morning, tapering off later this afternoon. Expect MVFR-
LIFR conditions for lower elevations, along with persistent
mountain obscurations to start the day, with conditions improving
steadily through the afternoon and evening. Clearing skies and
light wind overnight will result in rapidly cooling temps and a
good chance for fog across much of the region into Sunday
morning. BT

&&

.PRELIMINARY POINT TEMP/POPS...

    Tdy Sun     Mon     Tue     Wed     Thu     Fri
-------------------------------------------------------
BIL 051 038/068 046/076 045/057 040/061 041/060 041/061
    9/R 10/B    01/B    45/W    22/W    34/W    33/W
LVM 049 032/064 040/068 036/052 033/053 030/052 030/053
    7/R 10/B    01/N    45/T    33/T    34/W    33/W
HDN 052 034/069 040/080 043/059 036/065 036/062 037/064
    9/R 10/B    01/B    45/W    32/W    24/W    33/W
MLS 051 037/068 043/081 047/063 038/066 037/066 039/067
    8/R 10/B    00/U    34/W    22/W    24/W    33/W
4BQ 050 036/069 041/080 046/061 037/065 036/065 038/065
    5/R 10/B    00/U    25/W    42/W    24/W    43/W
BHK 049 035/066 040/079 047/065 039/066 038/067 040/066
    6/R 20/B    00/U    23/W    32/W    23/W    32/W
SHR 050 031/066 038/077 042/055 032/059 034/058 033/058
    7/R 10/U    00/U    35/T    43/W    34/W    33/W

&&

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

&&

$$
weather.gov/billings



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