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-- Discussion containing changed information from previous version are highlighted. --
000
FXUS65 KBOU 210207
AFDBOU

Area Forecast Discussion
National Weather Service Denver/Boulder CO
807 PM MDT Fri Oct 20 2017

.UPDATE...
-- Changed Discussion --
Issued at 754 PM MDT Fri Oct 20 2017

Pcpn was increasing across wrn CO and will gradually
move into the mtns as mid lvl qg ascent associated with
the upper level trough moves across overnight.  Snow amounts
over the higher mtns will range fm 2 to 6 inches.  Across
the plains, a band of showers may dvlp by 09z closer to the WY
border and then move quickly across the far nern plains by 14z
as a cdfnt moves across. Behind the fnt gusty NWLY winds will
occur with a few gusts fm 40 to 50 mph for a few hours especially
closer to the WY border.
-- End Changed Discussion --

&&

.SHORT TERM...(This evening through Saturday)
Issued at 340 PM MDT Fri Oct 20 2017

This evening a 700 mb front will move through bringing very
strong cold air advection. Late today into tonight, the higher
mountains are forecast to reach 45 kts, especially across the
northern mountains and Wyoming border. Lows tonight will drop
into the 40s on the plains and will be near 20-30 F over the
mountains. Highs Saturday will remain cooler, only expected to
reach 50-60 on the plains and 30-40 across the higher terrain.
Near the Wyoming border the gusts could return to around 40 kts.

Snow accumulation of 2 to 5 inches is expected Friday night into
Saturday morning above 8500 feet. At this point, we don`t feel
the need for any highlights.

.LONG TERM...(Saturday night through Friday)
Issued at 340 PM MDT Fri Oct 20 2017

Strong northwest flow overnight and a surface lee trough will
result in strong downsloping winds over the foothills. While the
rest of the plains will likely hit freezing or below, areas in and
along the foothills will remain warmer. Gusts of 40 to 50 mph
will be common, especially in the wind prone areas.

Northwest flow will continue Sunday through Wednesday bringing dry
weather to the area. After a warm up on Sunday, a shortwave
trough sinking down over the Great Plains and Great Lakes will
push in cooler air. Wednesday will warm up again as the next
system drops down out of western Canada.

Latest models have all trended much deeper and colder with the
expected system on Thursday. GFS, the Canadian and EC now will
have snow levels down over the plains with the quick moving
system. With it being in Day 7 and having the potential for more
differences in the models due to effects from Typhoon Lam that
gets caught up in the flow next week, have lowered the
temperatures for Thursday and Friday, but will keep it still warm
enough for rain over the plains during the day Thursday then down
to snow. The moisture will push south Friday for a dry day but
colder air will likely still linger.

&&

.AVIATION...
-- Changed Discussion --
(For the 00Z TAFS through 00Z Saturday evening)
Issued at 754 PM MDT Fri Oct 20 2017

Winds have switched back to SSW early this evening.  Overnight
latest data has winds becoming more NW around midnight and then N
or NE by 09Z lasting thru 12Z Sat. This is somewhat different
than what was shown earlier, so overall confidence is not high
for winds directions and speeds late tonight. On Sat gusty NWLY
winds should gradually dvlp after 15Z.
-- End Changed Discussion --

&&

.BOU WATCHES/WARNINGS/ADVISORIES...
None.
&&

$$

UPDATE...RPK
SHORT TERM...Sullivan
LONG TERM...Kriederman
AVIATION...RPK