Area Forecast Discussion
Issued by NWS Denver/Boulder, CO

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FXUS65 KBOU 051658

Area Forecast Discussion
National Weather Service Denver/Boulder CO
958 AM MST Tue Dec 5 2017

Issued at 958 AM MST Tue Dec 5 2017

Forecast on track with mostly sunny skies and temperatures
returning to near normal this afternoon. Next cold front is still
on track to reach the forecast area by early Wednesday morning.
Stronger northerly winds behind that front, and below normal
temperatures come Wednesday.


.SHORT TERM...(Today and tonight)
Issued at 227 AM MST Tue Dec 5 2017

A dry and subsident northwesterly flow aloft will be over the
region today. A weak upper level disturbance embedded in the flow
aloft will slip across the region tonight, bringing in a weak
frontal boundary from the north towards 12z Wednesday.
Temperatures will be near normal today, with no precipitation
expected. Mostly clear to partly cloudy overnight as well, with
limited moisture and no precipitation expected.

.LONG TERM...(Wednesday through Monday)
Issued at 227 AM MST Tue Dec 5 2017

A high amplitude ridge will remain parked along the west coast of
North America this week and into next week. Downstream, a long
wave trough will be over the eastern part of the U.S. and Canada.
North to northwest flow aloft will be the prevailing pattern over
Colorado for the upcoming week.

Wednesday and Thursday will be cool under a northerly flow aloft.
A short wave trough embedded in the northerly will bring a
reinforcing shot of cooler air Thursday. With this wave, there may
be enough moisture for light snow. The best chance will be over
the north central mountains where orographic lift with help
produce snowfall. Favored mountain locations could see 2-6 inches
of snow with less in the valleys and foothills. A light dusting
can`t be ruled out south of I-76. However, with this system coming
from the north, little moisture will accompany it and any
precipitation should be light where it occurs. Windy conditions
will be a good bet with a strong surface high over the Great
Basin. The mountains and eastern plains should experience the
strongest winds, while the Front Range will be somewhat sheltered
from the northwest winds.

Models are in good agreement showing the ridge shifting a little
eastward Friday and for the weekend. The cooler air is expected to
move east of the state. Highs will climb above normal Friday and
are expected to remain well above normal this weekend.
Breezy/windy conditions will remain possible through the weekend
due to the surface high remaining over the western states.

The ECMWF shows a weak short wave trough diving south across the
area Monday. The GFS doesn`t have this feature. If the ECMWF pans
out, this system should just bring a cool down.


.AVIATION...(For the 18Z TAFS through 18Z Wednesday afternoon)
Issued at 958 AM MST Tue Dec 5 2017

VFR conditions will prevail through Wednesday. Southerly winds
are expected to turn more southeasterly through this afternoon,
and perhaps northeasterly 22Z-00Z. Winds may not turn back to
normal south/southwest winds tonight and could stay a bit more
southeasterly, but speeds only 10 knots or less. Then cold front
Wednesday morning will bring gusty north winds 15-20 knots with
gusts around 30 knots, strongest at KDEN. Stronger winds should
arrive by 17Z Wednesday.




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