Area Forecast Discussion
Issued by NWS Billings, MT

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FXUS65 KBYZ 222106

Area Forecast Discussion
National Weather Service Billings MT
306 PM MDT Sat Apr 22 2017

.SHORT TERM...valid for Sun and Mon...

Ridge quickly building over the region today with pleasant
conditions for most locations. There is a little instability in
the NW flow aloft affecting the eastern CWA. Satellite shows some
cumulus fields developing. Sprinkles or virga a possibility, but
by sunset it should all fade away. Fog a possibility tonight with
all the rain we have had. Added a mention to eastern sections and
along some river valleys over east central Montana.

Strong trough moving into Pacific NW will induce backing flow
aloft over our region Sunday. Short wave energy scoots across
central Montana Sunday afternoon and produces some lift to work on
the Pacific moisture ushered into our area. Scattered to isolated
showers and thunderstorms look like a decent bet as jet dynamics
will help support convection as well. Activity may extend into
the overnight hours as well, mainly in the east. More short wave
energy races into the SW mountains by Monday morning taking a
similar track as previous energy has the last few weeks...mainly
across the WYO/MT border. This should result in a rather unsettled
start to the work week persisting into Monday night, especially
over our southern zones.

The precipitation should pretty much remain rainfall for the
lower elevations through Sunday and Monday, but look for periods
of snowfall over the high country. Quick snow bursts of 3-6
inches above 6500 FT at times is possible based on model progs.
Some areas in the higher elevations could see 6-10 inches Sunday
evening through early Tuesday morning. We will issue a Hazardous
Weather Outlook due to cooler wet weather and maybe some travel
impacts over the mountains to start the week. BT

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

Unsettled pattern for the week with focused periods favoring
better chances for precipitation. First of these periods is
Tuesday as a system that moves over Monday evening begins to
deepen Tuesday morning as the trough deepens over the Dakotas.
This supports a window of heavier precipitation over southeast
Montana which could be mixed with snow or be all snow for Carter
and Fallon counties with places like Alzada seeing decent
accumulations. Will be clearing from west to east Tuesday
afternoon but would still expect some diurnal shower activity.

Wednesday is unsettled but less dynamic before a stronger period
of height falls moves in for Wednesday night into Thursday.
Models in disagreement in the rate of the height falls with the
GFS now the most aggressive model and developing a broad cutoff
low over Wyoming. The ECMWF carves out a trough but the main low
is over Saskatchewan. Either way its a unseasonably cool period
with a chance for wet. Lower elevation snowfalls could be possible
in this period especially for places like Sheridan. Models do not
break the colder and damp solution until later in the weekend.



Weak upper level ridge moving across the area bringing a period of
clearer skies to the region. Expect patches of fog to return
tonight to southeast Montana possibly impacting KMLS and KBHK.
Otherwise VFR and light winds expected. borsum


    Sun     Mon     Tue     Wed     Thu     Fri     Sat
BIL 042/064 042/058 041/054 038/054 037/051 036/053 038/058
    02/T    53/T    65/T    44/T    74/R    33/R    22/R
LVM 039/060 037/055 035/054 034/052 033/050 031/052 031/056
    05/T    65/T    66/T    36/T    44/R    43/R    22/R
HDN 039/068 042/061 040/055 038/057 038/052 036/055 037/059
    02/T    43/T    66/T    36/T    74/R    33/R    22/R
MLS 041/064 042/059 038/053 036/055 037/051 037/055 037/060
    01/E    42/W    34/R    24/R    24/R    33/R    21/B
4BQ 040/068 043/060 038/051 034/053 034/046 034/053 035/058
    00/B    32/W    56/R    23/R    46/R    33/R    22/R
BHK 037/058 036/054 030/049 029/051 031/050 032/053 032/057
    01/B    42/W    23/O    22/R    24/R    32/R    21/B
SHR 037/066 040/056 038/050 034/052 035/046 032/049 034/053
    01/B    34/T    77/T    35/T    46/R    33/R    22/R




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