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Area forecast discussion 
National Weather Service Billings Montana
329 PM MDT Tuesday Oct 21 2014

Short term...valid for Wednesday and Thursday...

Surface observation are showing the cold front is moving into our far
western zones. A few thunderstorms have developed along and just
ahead of the front across Gallatin County and northern Park County
during the past couple of hours and are quickly moving to the
north and northeast. Clouds will continue to increase slowly
through the remainder of this afternoon and evening. Will continue
with just a slight shower chance and an isolated thunderstorm
chance along and west of a Sheridan- Billings- Roundup line this
afternoon with increasing chances this evening as better dynamics
are just behind the front. Precipitation chances will shift east during
the overnight hours but the strongest dynamics look to move to the
north of our forecast area across northeast Montana. Main impact
with this system will be gusty winds along and especially behind
the front. However...the system does not look as windy as last
weeks frontal passage. 700mb winds are only 25 to 35 kts tonight
through Wednesday with 850mb winds 25 to 35 kts tonight and 20 to
25 kts Wednesday. As a result...gusts across the area are expected
to be in the 35 to 45 miles per hour range with a few possibly close to 50
miles per hour.

The system will quickly exit into North Dakota by early afternoon
Wednesday but there will still be enough instability to warrant a
slight shower chance during the morning across the east. Next
system approaching the Pacific northwest Wednesday afternoon will
allow ridging to quickly build across Montana during the afternoon
and overnight hours. Although ridging begins to build during the
afternoon....high temperatures will be about 10 to 15 degrees
cooler today but still slightly above normal for this time of
year. By Thursday...a surface low will move across southern Canada
resulting in Lee-side troughing and a downslope surface flow
across our area. Mostly sunny skies combined with a downslope flow
will allow temperatures to warm back above normal with readings in
the upper 60s to lower 70s with dry conditions. Hooley

Long term...valid for Friday...Sat...sun...Mon...Tue...

Models are in very good agreement through the extended period
lending good confidence to the forecast. Changes to the going
forecast are of a minor nature. Overall a more progressive fall
pattern is starting to develop pushing systems through the area
every few days...though still no strong low pressure systems on
the horizon that could bring significant precipitation.

Zonal flow on Friday has a decent moisture feed associated with
it for possibly a few mountain showers and extensive cloud
cover...but downslope should keep lower elevations mainly dry.
Ridging develops aloft Saturday ahead of a strengthening West
Coast trough. This will bring dry and warmer conditions for
Saturday but as the upper trough slowly approaches will see
precipitation chances increase Sunday and Monday. However a
significant downslope gradient and the progressive nature of this
system will prevent more than a 20 to 30 percent chance for
precipitation for the lower elevations...though it could be
significantly higher for mountain locations where strong pulse of
Pacific moisture moves over the area. Temperatures will drop from
the 70s Saturday toward more seasonal levels as the upper trough
kicks through the region Sunday and Monday. Brief ridging develops
on Tuesday for slightly warmer temperatures before another shot of
Pacific moisture pushes over the area middle week. Chambers
&&

Aviation...

VFR conditions will prevail tonight. A cold front will move
through the area this evening with west to northwest winds gusting
30 to 40kts at times. Isolated shower and thunderstorm activity is
possible along and just behind the front...with local MVFR
conditions and wind gusts to 45kts associated with the stronger
cells. Occasional mountain obscuration can be expected tonight.
Winds will weaken during the early morning hours. Chambers
&&

Preliminary point temp/pops...

Wednesday Thursday Friday Sat sun Monday Tuesday
-----------------------------------------------------------
bil 045/065 042/070 047/066 041/073 044/057 036/055 035/058
31/b 00/u 00/b 00/u 12/west 21/b 11/b
lvm 040/061 039/067 043/065 041/072 041/055 031/053 032/055
51/b 00/north 01/b 10/u 13/west 21/b 11/b
hdn 043/067 038/073 043/070 038/074 040/060 034/057 032/059
21/b 00/u 00/b 00/u 11/b 21/b 11/b
mls 045/065 037/072 043/069 041/070 042/062 033/054 031/056
21/b 00/u 00/b 00/u 01/b 21/b 11/b
4bq 044/065 037/071 042/069 040/073 042/061 034/054 031/056
21/b 00/u 00/b 00/u 01/b 21/b 11/u
bhk 044/062 035/070 040/067 038/067 041/059 032/050 029/052
21/b 00/u 00/b 00/u 01/u 21/b 11/u
shr 041/065 034/072 040/071 037/076 038/060 030/055 027/057
21/b 00/b 00/b 00/u 11/b 22/west 11/b

&&

Byz watches/warnings/advisories...
Montana...none.
Wyoming...none.

&&

$$
Weather.Gov/Billings

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