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Area forecast discussion 
National Weather Service Billings Montana
450 am MST Thursday Nov 26 2015

Short term...valid for today and Friday...

Updated to add patchy fog to locations along the Yellowstone

Water vapor imagery shows an upper low over northern Utah with a
shortwave lifting into north central Wyoming. This energy is helping to
reinforce some light precipitation in Sheridan County and far southeast
Montana...and spreading high cloud as north as lvm-bil-mls. Given the
lingering precipitation will let the winter weather advisories ride a bit longer
for these areas...but have cancelled southern Bighorn County. The
Wyoming energy is in competition with drier northern branch wave
dropping into Montana and the northern plains...the latter of which
will win out once 110kt jet in eastern Wyoming moves further east. Thus
a dry day is in store for US once the morning precipitation tapers off.
Upper low to our south will become cut off completely tonight
setting up an unusually strong Rex block over the western
Continental strong ridging builds over western Canada. This will
allow for our County Warning Area to remain under the influence of easterly flow
aloft and the cold Canadian surface ridge for the next couple days...
with dry conditions tonight through Friday night.

Temperatures will remain well below normal through Friday and have continued
to lean on the cool side of guidance given the freshly acquired
snow cover. Coldest air early this morning is in our N/ is
already six below at Wilsall and zero at Harlowton. By tonight surface
ridge will slide south and with clearing skies our S/southeast parts
should see colder temperatures with many locations dropping below zero.
Will be interesting to see how cold Sheridan will get...-10f or
colder is a possibility. Nighttime lows will begin to moderate by
Friday night.


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

As of this update several inconsistencies still exist in the
global guidance. Mostly in the handling of the upper level low
that brought snow to the forecast area on Wednesday.

Long term period will begin with split upper level flow over the
western US. This split flow will allow the upper level low to
remain over the region on Sunday before a disturbance approaching
the western Continental U.S. Disrupts the flow aloft late Sunday...helping
to kick the low to the east. While this happens some wrap around
moisture and some instability rotating around the low could help
kick off a round of snow showers late Sunday into the day Monday.
Model spread is large in the handling of placement...and amount of
precipitation...but it does appear locations near Miles
City...Hardin...Sheridan...and locations south and east...stand
the better chances for precipitation.

After Monday...and depending on the speed in which the stubborn
upper level low moves east...we should see the warmup trend
continue. This will be in association with and upper level ridge
moving into region. Model to model differences remain in the
placement and strength of the approaching ridge but we should be
able to break out of the freezing mark by Monday afternoon. Maximum
temperatures should warm to the middle 40s by Thursday of next week.
With cool morning lows in the 20s. Dobbs


VFR conditions prevail across the region except for occasional
MVFR ceilings near kshr and IFR ceilings at klvm...where low level
stratus is possible through 15z. Kshr should see conditions
improve by late morning...though lower level VFR ceilings could
occasionally yield MVFR conditions through 20z. Klvm should begin
clearing out around 15z as dry air advection slowly erodes the
broken stratus deck. A period of vlifr fog will impact kbil
through 14-15z. Dobbs


Preliminary point temp/pops...

Today Friday Sat sun Monday Tuesday Wednesday
bil 022 002/023 009/027 014/029 017/034 022/040 025/042
0/b 00/u 01/b 22/j 21/b 10/u 01/u
lvm 021 902/024 005/028 012/030 013/035 018/038 019/041
0/u 00/u 01/b 32/j 11/b 10/b 01/u
hdn 022 903/026 005/027 013/028 015/032 017/038 021/040
0/b 00/u 01/b 32/j 22/j 10/u 00/u
mls 024 000/026 008/030 017/030 018/032 017/036 021/040
0/b 00/u 01/b 22/j 22/j 10/b 00/u
4bq 021 905/026 007/030 016/029 015/032 016/036 020/038
2/S 00/u 12/j 42/j 22/j 10/b 01/u
bhk 022 901/027 008/032 016/030 018/032 015/034 020/040
0/b 00/u 01/u 22/j 32/j 10/b 00/u
shr 018 908/023 004/026 014/029 013/031 014/036 016/041
3/S 00/u 13/j 33/j 32/j 10/u 01/u


Byz watches/warnings/advisories...
Montana...Winter Weather Advisory in effect until 11 am MST this
morning for zones 36-37.
Wyoming...Winter Weather Advisory in effect until 11 am MST this
morning for zones 98-99.



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