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Area forecast discussion...updated 
National Weather Service Billings Montana
907 am MDT Tuesday Oct 6 2015


Locally dense fog has developed over most river valleys east of
Billings. Visibility has dropped to under a mile in Sheridan and
Miles City due to this fog. Given that the fog is localized to the
immediate river valleys have not gone with a dense fog
advisory...but drivers on I-90 around Sheridan and I-94 in the
Miles City area should slow down and be cautious when fog is
encountered. Extended fog mention until noon for those areas as
well. Outside of the morning fog should be a beautiful early fall
day with temperatures around 70...sunny skies and light winds.


Short term...valid for today and Wednesday...

Ridging will continue to work into the area through today. With
the clear skies overnight...patchy fog has developed across the
eastern zones. Near the Dakotas some areas dense fog are possible.
Today a weak wave of energy coming off the the cut off low over the
southwest. There will be enough moisture and energy with the wave
that the mountains could see some light rain. For the rest of the
area today should be dry with temperatures getting into the 70s.

For Wednesday the ridge becomes a weak wave will
flatten the ridge out some. This will give some instability to
create some more rain chances over the mountains. Temperatures
will continue their upward trend and will be well into the 70s.

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

Thursday will be a Post frontal environment and a narrow plume of
tropical moisture will be moving over the region with building
heights. Could see some mountain shower activity but plains should
stay dry with temperatures a bit cooler than Wednesday due to
clouds and weak mixing.

Friday and Saturday ridging tries to develop over the area but
energy streaming in from the Pacific will keep flow near zonal and
support leeside troughing. This brings a warm and breezy couple of
days. Sunday the ridging breaks down even more and pressure
gradients couple with strong mixing and a pre frontal environment
to bring the strongest periods of winds. European model (ecmwf) is a bit faster
with this front compared to GFS but in general the impacts are the
same just differences in timing. Saturday looks to be near record
high temperatures and Sunday could be as well depending on timing.

Behind this front flow aloft remains energetic and low level flow
downslope but surface high pressures are not as strong over
southeast Idaho and western Wyoming so winds should not be quite
as strong. Borsum



Mostly clear skies with light winds for most of the region. Fog
along the Montana Dakota border will impact Carter and Fallon
counties and some valley fog may be encountered near kmls and
kshr. Fog should dissapate by 16z but some isolated locations
could see some IFR visibilities until 17z. VFR conditions expected to
prevail by 18z. Borsum/Dobbs


Preliminary point temp/pops...

Today Wednesday Thursday Friday Sat sun Monday
bil 069 048/074 048/069 050/079 054/083 054/082 050/072
0/u 00/b 11/east 10/b 00/u 00/u 11/north
lvm 072 044/072 044/069 045/078 049/081 049/077 046/070
0/u 00/north 21/east 11/b 00/north 01/north 11/north
hdn 072 045/076 046/070 046/081 049/085 050/084 048/074
0/u 00/b 11/b 10/b 00/u 00/u 11/b
mls 070 048/076 045/069 048/079 053/084 052/082 049/073
0/u 00/b 11/b 00/b 00/north 00/u 11/b
4bq 071 049/076 047/068 047/079 051/084 051/084 048/073
1/b 10/b 11/b 00/b 00/u 00/u 11/b
bhk 067 047/074 044/066 045/076 050/081 050/080 047/070
0/u 11/b 00/b 00/b 00/north 00/u 10/north
shr 071 044/076 045/068 043/079 046/085 047/085 045/073
2/west 00/b 12/west 10/b 00/u 00/u 11/u


Byz watches/warnings/advisories...



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