Area Forecast Discussion
Issued by NWS Denver/Boulder, CO

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FXUS65 KBOU 011038

Area Forecast Discussion
National Weather Service Denver/Boulder CO
338 AM MST Thu Dec 1 2016

.SHORT TERM...(Today and tonight)
Issued at 247 AM MST Thu Dec 1 2016

An upper level trough will move southward fm the nrn Rockies as an
upper level low develops over Utah by late tonight.  Ahead of this
system there will be an increase in mid lvl moisture.  Cross-
sections show the mid lvl flow will switch fm wly to more swly by
late in the aftn with weak orographic component. QG ascent is weak
as well although there will be some improvement in lapse rates.
Overall there will be a chc of light snow in the mtns mainly north
of I-70. Across nern CO outside of increasing cloud cover it will
be dry with highs similar to Wed.

For tonight wk swly mid lvl flow will continue in the mtns with a
continued chc of light snow.  Across nern CO the low lvl flow will
become light ese with a dry layer abv the sfc.  After 09z the lower
levles may become more saturated which may lead to a slight chc of
light snow in and nr the foothills.  Across the rest of nern CO it
will remain dry.

.LONG TERM...(Friday through Wednesday)
Issued at 247 AM MST Thu Dec 1 2016

The upper trof will continue to dig south and southeast into
southern Arizona during the day on Friday as the low becomes
closed off. Meanwhile over Colorado,  there is still some weak QG
ascent remaining while northern branch of the trof sweeps across
Colorado on Friday night and early Saturday. At the surface...high
pressure will build through region with light and shallow upslope
flow on Friday before shifting southeast Friday night. There is a
moist layer from 750-550mb and given shallow upslope component may
be enough for scattered snow showers especially in/near the
foothills. Not much in the way of orographic flow in the mountains
so any accumulations will be on the light side.

Drier conditions will move into Colorado on the weekend as a
moderate northwest flow pattern sets up. Could be a few lingering
snow showers in the mountains with the northwest flow and some
gusty winds over mountains and higher east slopes with speeds
generally under 35 mph. Expect some moderation in temperatures
across lower elevations with readings back into the 40s.

Next major system digs into the Great Basin early next week with
the next shot of much colder temperatures and the chance of snow.
Still some significant differences showing up between the GFS and
European solutions with the GFS now more progressive than earlier
runs while European is slower but still moves the trof across
Colorado as an open wave. Even GFS ensemble memers are quite
varied. Regardless temperatures will be much colder with this
system. Have lowered temperatures on the plains for Tuesday and
Wednesday while maintaining chances of snow.


.AVIATION...(For the 12Z TAFS through 12Z Friday morning)
Issued at 247 AM MST Thu Dec 1 2016

Winds will remain light sly this morning and then become more ely by
early aftn.  There will be a mid lvl cloud deck around 15000 ft thru
the aftn hours.

For tonight winds will be mainly sely in the evening and become
light ene after 06z. Ceilings will be around 12000 ft and may drop
to around 8000 ft by 12z.  At this time any threat for a little
light snow late tonight into Fri morning will likely focus closer to
the foothills.




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