Area Forecast Discussion
Issued by NWS Denver/Boulder, CO

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FXUS65 KBOU 062144

Area Forecast Discussion
National Weather Service Denver/Boulder CO
244 PM MST Tue Dec 6 2016

.SHORT TERM...(This evening through Wednesday)
Issued at 154 PM MST Tue Dec 6 2016

Light radar echoes have blossomed over the mountains and northern
Front Range...foothills...and northern front range.  Not much has
been reported at the ground...but the process has begun.  I had
considered delaying the start of the mountain advisory...but snow
will begin impacting roads during the afternoon. For the lower
elevations...the Ruc13 shows snow starting in the metro area
around 3z...the HRRR around 07z...the Nam after 03z...the GFS
after 03z. Will mention mid evening as a starting time...this is
good news because the evening rush should not be severely
impacted. The morning rush is another story, as snow is expected
to fall through mid morning Wednesday and roads will likely become

snow accumulations are another difficult forecast today...latest
SREF plume forecasts give a mean of 2-3 inches over much of
northeast Colorado...with barely an inch at Limon. In the Urban
Corridor the numbers were a bit higher. I was considering an
extension of the advisory to cover parts of northeast Colorado...but
these snow amounts in eastern Colorado were below criteria. snow
will begin to decrease across the area during the afternoon on

Temperatures will be frigid tonight and tomorrow. With clouds the
mountain valleys will be warmer...but eastern Colorado will have
lows in the single digits tonight...and mid teens on Wednesday.

.LONG TERM...(Wednesday night through Tuesday)
Issued at 154 PM MST Tue Dec 6 2016

By Wednesday night subsidence will be moving in over the region
bringing clearing skies and snow to an end by late Wednesday.
Winds will be light and combined with clear skies bring overnight
temperatures below zero over the forecast area. Mountains could
see temperatures fall overnight to -20...especially in the

On Thursday increasing NW flow aloft will bring a continual supply
of moisture to the mountains with some polar jet influence keeping
orographic snow possible. Temperatures will moderate on the plains
but with snow on the surface and some lingering cloud cover
expect temps to be slow to increase so kept highs lower then
guidance. by late Thursday the jet stream will drop south
bringing instability to the Northern Mountains and increase
snowfall intensity slightly. The strong westerly flow will create
downsloping off the foothills and keep the plains dry.
Temperatures on Thursday will continue to be below normal with
highs in the teens increasing back into the 40s by Friday.

Conveyer of moisture will continue to move into Colorado from the
NW as the jet moves south over the state by the weekend. This
will create increasing snow for the mountains with a slight chance
on the plains by Saturday evening with the passage of a cold
front late Saturday. The front will turn surface winds more
northerly...however, model guidance has just limited moisture for
the plains so do not expect much in the way of accumulation.
Temperatures for the weekend will drop once again but only into
upper 30s and lower 40s. winds will increase in the mountains with
the help of the upper jet with gusts up to 50 mph possible at
higher elevations. This will cause areas of blowing snow and
possible hazardous driving conditions for weekend travelers.

The weather pattern will remain active into the start of next week
with winds at lower elevations as the jet remains over the state.
Temperatures will average closer to normal by monday into Tuesday.


.AVIATION...(For the 18Z TAFS through 18Z Wednesday afternoon)
Issued at 154 PM MST Tue Dec 6 2016

Models have a different idea of starting time for snow in the
Metro area...right now it is looking like it will be after 03z.
But the general forecast is on track for lowering ceilings...reaching
ifr conditions in snow during the evening. snow will continue
through much of wednesday morning...with ceilings improving in
the afternoon.


Winter Weather Advisory from 6 PM this evening to noon MST
Wednesday for COZ035-036-038>041.

Winter Weather Advisory until noon MST Wednesday for COZ031-033-



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