Scientific Forecaster Discussion

Return to Local Conditions & Forecast

Without Abbreviations
With Abbreviations

Area forecast discussion 
National Weather Service Billings Montana
229 PM MST Monday Nov 30 2015

Short term...valid for Tuesday and Wednesday...

A quiet weather pattern is in store for the next several days.
The stubborn upper low that has been influencing our weather since
last Wednesday is currently over Iowa and Nebraska. This low
continues to wrap clouds westward into southeast Montana this
afternoon and will continue to do so through this evening. These
clouds are mainly middle level but they will bring a chance for a
snow shower across Fallon and Carter counties this evening with
the best chances after midnight. Elsewhere...expect a clear to
partly cloudy night. Overnight lows tonight will be a bit milder
than last night due to some clouds around but mainly as a result
of a downslope flow developing across the entire area especially
from Billings westward to the foothills locations.

Tuesday & Wednesday...the upper low finally shifts east into the
Great Lakes area Tuesday and Wednesday. This will allow upper
level ridging to begin to build across the northern rockies on
Tuesday. An upper low and trough across the eastern Pacific will
help the ridge to build more so during the day Wednesday. In
addition...Lee-side troughing will set up both days resulting in
breezy to windy conditions and a downslope flow...mainly across
the upper Yellowstone and Stillwater valleys. Pressure gradients
across this area tighten late tonight and again Tuesday night but
the orientation is more east/west and not conducive to strong
and/or high winds. Although it will be windy...we are not
expecting any wind highlights at this time through the short term
period. Temperatures will continue to moderate each day given
downslope flow with readings by Wednesday above normal in the
lower to middle 40s. Hooley

Long term...valid for Thursday...Fri...Sat...sun...Mon...

Thursday & Friday...the extended period looks to be mild with
periods of wind at times. Models are in fairly good agreement but
diverge by the end of next weekend into early next week. A large
trough will approach the West Coast Thursday and move onshore
Friday which will allow upper level ridging to continue across the
forecast area. At the same time...Lee-side troughing will be in
place resulting in periods of wind especially across the upper
Yellowstone and Stillwater valleys. A Pacific front will move
across the area Friday night but the only impact expected is a
gusty west wind and slightly cooler temperatures on Saturday.

Saturday into Monday...the Pacific trough moves across the
intermountain west Saturday but there won't be much if any energy
associated with it as it moves across our forecast area. The bulk
of the energy splits and shifts south across The Four Corners
region. Upper level ridging once again will build across the area
for Sunday. Another disturbance will move across the northern
rockies Monday flattening the ridge once again ushering in a fast
zonal flow aloft across our area. We are not expecting any precipitation
across the area through the extended with the exception of some
possible mountain snow showers. Temperatures will be above normal
through the period. Hooley



VFR conditions are expected through the taf period. Southwest
winds will continue in klvm...increasing overnight...with gusts
approaching 30 knots by Tuesday morning. Otherwise no aviation
hazards are expected across the region. Gilstad


Preliminary point temp/pops...

Tuesday Wednesday Thursday Friday Sat sun Monday
bil 018/038 023/044 026/045 030/048 028/046 026/047 030/047
00/north 00/u 00/b 00/b 11/u 00/b 01/b
lvm 019/035 022/041 030/047 031/047 025/042 026/045 028/045
00/north 00/north 00/north 01/north 11/north 00/north 11/north
hdn 011/038 012/040 016/044 020/047 024/044 019/044 023/046
00/b 00/u 00/b 00/b 11/u 00/u 01/b
mls 009/032 014/039 018/042 021/048 025/042 023/044 024/045
00/b 00/u 00/u 00/b 00/u 00/u 01/b
4bq 014/035 013/042 019/044 027/050 027/045 023/046 024/049
10/b 00/u 00/u 00/b 00/b 00/u 01/b
bhk 008/030 014/040 019/044 023/047 024/043 021/046 021/046
21/b 00/u 00/u 00/b 00/b 00/u 00/b
shr 012/038 015/041 019/043 023/047 022/043 020/046 024/047
00/b 00/u 00/u 01/b 11/b 00/u 01/b


Byz watches/warnings/advisories...



National Weather Service Glossary of Abbreviations