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Area forecast discussion 
National Weather Service Billings Montana
321 am MDT Friday Aug 29 2014

Short term...valid for today and Sat...

Strong divergence aloft related to a nice short wave tracking
across our region appears to be the driving force behind an area
of thunderstorms and frequent lightning early this morning across
our central zones. Q vector forcing associated with this wave
exits the state this morning...but look for some lingering showers
and lightning possible in the eastern sections of our forecast
area due to instability as cold pool moves over the region. We may
see some showers over the mountains in the afternoon as well from
differential heating/instability.

Another short wave and associated cold front sweep through the
area on Saturday...and are reinforced by some additional energy
carving out a path through the central rockies Saturday night.
Model proggs point to a risk over severe thunderstorms in the far
eastern counties late Saturday...though some strong storms are
possible over the west as well due to some moderate shear profiles
and decent forcing from upper jet dynamics. Based on the
considerable dynamic influences and tap of Pacific moisture I
have raised probability of precipitation a little more for Saturday afternoon and Saturday
evening. Bt

Long term...valid for sun...Mon...Tue...Wed...Thu...

Minimal changes once again to the extended period...with models
remaining in pretty good agreement throughout the extended period.

A low chance for showers and thunderstorms will finish up the
Labor Day weekend. Unseasonably cool temperatures around 10 degrees below
normal are also expected through Monday...as a broad upper level
trough crosses the region. Zonal flow with rising heights...and some
degree of shortwave ridging will prevail through
Wednesday...resulting in another short dry period...and a bit of a
warmup. Temperatures slowly climb back to about average by
Wednesday...with temperatures into the low 80s. By Thursday another
Pacific trough is bringing southwest flow into the region. This
southwest flow appears to stay intact through the remainder of
the period...as the trough deepens. Specifics with relation to this
trough impacting the region remain uncertain with regard to
shortwave activity through the region...but models have been
consistent in deepening trough along the coast over last few model
runs. At this time models are also indicating monsoonal flow into
the region by Thursday evening/night and persisting through
Friday. Have introduced broad brush chance probability of precipitation at this time...and
kept temperatures cool to end the workweek. Aag
&&

Aviation...

Scattered showers and thunderstorms continue to spread eastward
across the area this morning...mainly east of a line from Roundup
to Billings to Pryor. Localized MVFR to IFR flight conditions can
be expected in precipitation. The Big Horn Mountains will remain obscured
through the morning. Isolated to scattered are expected in area
mountains throughout the day today...with associated local
obscurations expected. Aag

&&

Preliminary point temp/pops...

Today Sat sun Monday Tuesday Wednesday Thursday
-------------------------------------------------------
bil 076 056/073 053/071 050/073 050/076 052/080 053/074
1/b 15/T 62/T 22/T 21/u 11/u 22/T
lvm 080 051/070 044/068 043/071 044/076 045/079 046/075
1/b 17/T 62/T 22/T 21/u 12/T 22/T
hdn 078 056/077 053/072 051/075 051/078 052/082 054/078
1/b 04/T 52/T 22/T 21/u 11/u 22/T
mls 077 058/079 055/073 052/075 053/078 054/082 055/077
3/T 03/T 43/T 22/T 21/u 11/u 22/T
4bq 078 057/085 054/071 051/074 052/078 053/083 056/078
2/T 03/T 43/T 22/T 21/b 11/u 23/T
bhk 075 055/080 054/071 048/073 049/076 051/080 053/076
3/T 14/T 52/T 22/T 21/b 11/u 23/T
shr 078 053/081 051/069 047/073 046/078 048/082 051/079
2/west 03/T 42/T 22/T 21/u 11/u 22/T

&&

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

&&

$$
Weather.Gov/Billings

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