Area Forecast Discussion
Issued by NWS Denver/Boulder, CO

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FXUS65 KBOU 111801

Area Forecast Discussion
National Weather Service Denver/Boulder CO
1101 AM MST Thu Jan 11 2018

.SHORT TERM...(Today and tonight)
Issued at 1100 AM MST Thu Jan 11 2018

Web cameras showing a few pockets of light snow remaining in the
higher mountains. Don`t expect much in the way of additional
accumulation through mid evening with this snow. The snow will
increase in the mountains tonight as an upper level trough
approaches from the northwest. Moist adiabatic lapse rates and
mountain top winds of 30-50 knots will result in good orographic
lift over the mountains. Lift from the jet and the upper level
trough will also aid in lift tonight and Friday. Issued a Winter
Weather Advisory for late tonight through Friday. This system may
end up producing more snow in the mountains of Summit and Grand
county than the previous one. (About 3-6 inches fell in the last
storm). Updated the forecast to reflect the better chances for
snow and for the expected snow fall amounts. Expected snowfall is
expected to be in the 4-8 inch range with locally higher amounts
where orographic lift is best.

.LONG TERM...(Friday through Wednesday)
Issued at 413 AM MST Thu Jan 11 2018

A disturbance in NW flow aloft will move across the area on Fri.
Cross-sections show decent moisture in the mtns thru midday which
then decreases by aftn.  With favorable orographics and lapse rates
will see accumulating snowfall. Advisory amounts will be possible in
some places. In addition gusty winds will produce blowing snow
over the higher passes. Over nern CO there will be a chc of
rain/snow showers across the plains mainly in the morning hours as
the disturbance moves across. Winds will be gusty as well fm the
foothills across the plains. As for highs, downslope flow along
the front range will allow for highs close to 50 over the urban
corridor, while across the far nern plains readings will only be
in the 30s behind a cold front.

For Friday night into Saturday the flow aloft will remain Nwly with
only some mid and high lvl moisture embedded in the flow.  There
will still be enough moisture in the mtns to keep in a chc of
light snow thru Sat morning. Across the plains it will be dry with
aftn highs ranging fm the 30s over the far nern corner with lower
to mid 40s elsewhere.

On Sun dry Nwly flow aloft will be over nrn CO with no pcpn
expected.  Highs across nern CO will range fm the lower to mid 40s
over the far northeast corner with upper 40s to lower 50s elsewhere.
For Sun night into Mon NW flow aloft will remain in place,
however, a cold front will move across nern CO. Models seem to
warm with highs over nern CO based on 850-700 mb temps. Meanwhile
with an upper level jet over nern CO there could be some light
pcpn in association with the front on Mon.

For Tue into Wed a flat upper level ridge will build into the area
with dry conditions and a warming trend.


.AVIATION...(For the 12Z TAFS through 12Z Friday morning)
Issued at 1100 AM MST Thu Jan 11 2018

No aviation impacts are expected through the next 24 hours. Drier
air has moved over northeast Colorado which will remain in place
through Friday morning. Northwesterly flow aloft is producing an
anti-cyclonic eddy immediately downstream from the higher terrain
of the foothills. This will produce northeast winds around 18z.
These winds are expected to slowly turn clockwise and end up
southerly 03-06Z. Gusty west-northwest winds are expected after
15Z Friday with gusts to 30 knots possible.


Winter Weather Advisory from 11 PM this evening to 5 PM MST
Friday for COZ031-033-034.



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