Area Forecast Discussion
Issued by NWS Denver/Boulder, CO

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FXUS65 KBOU 161616

Area Forecast Discussion
National Weather Service Denver/Boulder CO
916 AM MST Mon Jan 16 2017

Issued at 915 AM MST Mon Jan 16 2017

Burst of heavier snow this morning is gradually tapering off per
latest radar returns. Appears drier working in from the north per
15 degree dewpoint depressions in Cheyenne and loss of lower
ceiling at KFNL. There has been a slight shift to almost due
northerly at KFNL and KGXY and we`re still in the deformation zone
so departure of snow could be delayed til at least the noon hour
for the Denver metro area. Additional accumulations from this
point forward should mostly be around an inch or less, with
perhaps up to 2 on the Palmer Divide area and points east where
more is deeper and northerly flow is more favorable for snowfall.


.SHORT TERM...(Today and tonight)
Issued at 355 AM MST Mon Jan 16 2017

Upper level low over Oklahoma will lift northeast across Kansas
today. The system will continue to move northeast and exit the
region this evening. Northeast upslope winds at 700 mb is helping
to produce snow along the Front Range at this time. Radar showing
the heaviest snow is occurring west of I-25. Moisture will
continue to wrap around the low move over northeast Colorado this
morning. With the low pulling away from the state moisture and
lift will decrease. Expect snow to end mid to late morning for
most locations. Upslope areas south and west of Denver and areas
closer to the low over the eastern plains will likely see light
snow linger into the early afternoon. Expect snow to end by sunset
everywhere as drier air moves in from the north. This drier air
will bring clearing skies. By 12z Tuesday, expect mostly clear
skies through out the forecast area. This will lead to chilly
overnight lows in the mountains valleys with lows approaching

As far as snowfall amounts go, temperatures in the mid 20s to
lower 30s should keep the liquid to snow ratio close to 10 to 1.
Expect 1 to 3 inches along the Front Range and across the eastern
plains. Upslope favored areas in and near the foothills could see
a little more snow, 2 to 5 inches. Will continue the Winter
Weather Advisory where additional snowfall should result in slick
roads this morning.

.LONG TERM...(Tuesday through Sunday)
Issued at 355 AM MST Mon Jan 16 2017

An elongated upper trough extending from the parent upper low over
the western Great Lakes to a lesser upper low just south of Arizona
may still provide sufficient mid-level shear...instability and
moisture for scattered to broken cloud cover over the srn third of
the fcst area to start the day on Tuesday. However any precip should
be south of the CWA by then. Through the day trough translates
eastward allowing drier and progressively warmer air to spread
eastward across the region beneath a strongly tilted upper ridge.
For the next two days daytime temperatures climb into the 50s at
lower elevations and into the 30s in the high country under
generally clear skies even as a weakly organized upper low ambers by
to our south. Models show this ridge east of the state Thursday
night which opens the door to a series of progressive shortwave
troughs...the first of these waves reaching western Colorado by
Friday morning. At this point it does not appear to be a prolific
snow producer with its relatively warm south-southwesterly mean
layer flow and near neutral QG forcing. As this wave swings out over
the northeast plains of Colorado could see a few light rain and/or
snow showers Friday afternoon and evening helped along by weak low-
level upslope flow. Then a break in precip with partial clearing
with a passing weak shortwave ridge early on Saturday...followed by
a return to a moist southwest flow as the next shortwave trough
moves in from Utah. Precip possibly heavier with this system but
still largely confined to higher terrain west of the Continental
Divide. Areas east of the mtns appear to miss out on most of this
precip with models showing the trough accelerating once it crosses
the Rockies. A moist and marginally unstable northwest flow on the
back side of this trough may continue to generate orographic
snowfall in the northern mtn ranges possibly until early Sunday
morning. Should then see rapid clearing and gradual warming from
west-to-east across the CWA on Sunday with a strong upper ridge
moving in from the Great Basin.


.AVIATION...(For the 18Z TAFS through 18Z Tuesday afternoon)
Issued at 915 AM MST Mon Jan 16 2017

Delayed departure of snow as discussed in updated section above.
Snow intensity is gradually decreasing and snow should be ending
between 19Z and 21Z. Additional accumulation less than an inch
from this point forward as heaviest snowfall is over, except at
KAPA where could see 1-2 more inches before decreasing and ending
an hour or so later than KDEN. IFR conditions in snow gradually
improving to MVFR and then VFR toward 21Z. Clearing skies
thereafter. Fog threat tonight should stay north of KDEN as long
as normal drainage winds pick up toward 06Z.


Winter Weather Advisory until 11 AM MST this morning for COZ041-



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