Area Forecast Discussion
Issued by NWS Denver/Boulder, CO

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FXUS65 KBOU 202140

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

.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...(For the 18Z TAFS through 18Z Saturday afternoon)
Issued at 340 PM MDT Fri Oct 20 2017

VFR conditions should persist through the next 24 hours. Winds
should be light from the southwest before a frontal passage. The
winds should begin gradually shifting to north/northwest with
speeds gusting up to 25 kts by 09Z. The front is expected to
occur around 09-11Z. This NNW direction is expected to persist
through much of the day Saturday and winds could gust as high as
30 kts.




SHORT TERM...Sullivan
LONG TERM...Kriederman
AVIATION...Sullivan is the U.S. government's official web portal to all federal, state and local government web resources and services.