Area Forecast Discussion
Issued by NWS Denver/Boulder, CO

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FXUS65 KBOU 240350
AFDBOU

Area Forecast Discussion
National Weather Service Denver/Boulder CO
850 PM MST Thu Feb 23 2017

.UPDATE...
Issued at 849 PM MST Thu Feb 23 2017

Shallow upslope remains along the Front Range with areas of light
snow, but all of the heavier snow has ended. Could see another
inch in a couple spots south/southwest of Denver but overall the
majority of this light snow will be ending and diminishing to just
a few flurries through the midnight hour as upslope component
weakens. A few flurries may linger overnight into early Friday
morning.

In the mountains, best snow has been observed in the northern
Front Range and Rocky Mountain National Park area. Only light
snow has occurred the last few hours and more of the same
anticipated overnight with generally weak orographic lift.
Advisory looks good through Friday morning with another 2-4 inches
expected.

On the northeast plains, snow has tapered off this evening as
expected as stronger lift heads through Nebraska. We will see
wraparound moisture through Friday morning however, and enough to
produce another 1-3 inches over the far northeast corner. Extended
the winter weather advisory there, but let northern Weld and
Logan counties go with a stronger downslope component off the
Cheyenne ridge.

Cold temperatures on track tonight with teens expected over the
plains (already below 20F at DIA), and single digits/below zero
mountain and foothill areas.

Finally, for Friday afternoon most models show some convective
snow showers redeveloping over the mountains and foothills in the
afternoon. Still some weak upslope component so a couple more
inches possible in areas that see more persistent showers. A few
of these should spill onto the I-25 corridor in lighter fashion,
while most of the plains will stabilize and dry into the
afternoon.

&&

.SHORT TERM...(This evening through Friday)
Issued at 300 PM MST Thu Feb 23 2017

Upper level elongated trough will continue to move eastward
through Friday with the jet staying to the south. A surface low
over SW Wyoming combined with a surface trough extending over the
eastern portions of the state will bring increasing northerly
winds to the plains. Northerly flow will bring sustained moisture
and help to keep light snow showers over the plains through Friday
morning...especially over the northern counties bordering
Wyoming. In the mountains snowfall intensity will diminish but
expect some accumulation on west facing slopes and some orographic
snow on the divide through tomorrow. Snowfall amounts on the
plains have ranged from 1 inch up to 7 over the northern counties
and foothills. Expect another 1-2 inches through the evening with
locally higher amounts under more intense bands this afternoon.
These bands could drop up to an inch of snow in an hour with
reduced visibility. Temperatures will remain below freezing with
highs today only reaching into the lower 30s dropping into the
teens overnight. This will cause slick and snow laden roads to
become icy and hazardous for morning commuters. Temperatures will
continue to be cooler with highs only in the mid to upper 20s for
Friday.

.LONG TERM...(Friday night through Thursday)
Issued at 300 PM MST Thu Feb 23 2017

Models continue to be in reasonably good agreement at least
through the weekend. Upper low over Nebraska is progged to slowly
track east gradually losing its grip on northeast Colorado. Weak
orographics and ongoing cold air advection producing modest post
trough instability should continue to generate light snowfall
across the high country and give the nearby plains a slight chance
of snow through Saturday morning. Through the day...a drier and
more stable upstream flow should bring an end to most snowfall in
most areas by Saturday afternoon as temperatures aloft begin to
warm with a shift to a more zonal flow. This strengthening flow is
expected to produce stg and gusty wly winds on the mtn range and
east slopes of the front Range on Saturday. Speeds should remain
below high wind criteria. Even with less cloud cover, weekend
temperatures are expected to remain below seasonal norms.

Next week, models show another vigorous shortwave trough carving
out over the Great Basin and reaching Colorado by Sunday
morning.Some of the models show light precip developing in areas
west of the Continental Divide by afternoon generated by a moist
and unstable west-southwest flow. Sunday night into Monday the NAM
and GFS models show this trough moving across the state with most
of its energy and moisture passing to the south of the CWA Sunday
evening. While the European and Canadian models show a flat upper
ridge passing over the state at the same time. For now will lean
towards the wetter of the NAM and GFS and keep a chance of snow in
the high country, but with a drop off in snowfall towards Monday
morning.

For the first half of next week...models show Colorado and the
western CONUS under the influence of a broad upper level trough
and a colder Canadian airmass. Snow chances look better for the
fcst region, starting with the high country Monday and Tuesday
and for the entire CWA late Tuesday and Wednesday. However, at
this time significant snowfall is not anticipated.

&&

.AVIATION...(For the 06Z TAFS through 06Z Friday night)
Issued at 849 PM MST Thu Feb 23 2017

Light snow will continue to decrease through 06Z with just a few
flurries expected by then. KAPA could see light snow linger a bit
longer but overall only a dusting to one half inch and most of
that toward KAPA. MVFR ceilings should prevail through Friday
morning, although some breakup to VFR is possible at times as
slightly drier low level air moves in. Chance of snow showers
redevelops Friday afternoon mainly after 20Z, favoring locations
closer to the foothills including KBJC and KAPA. Any accumulation
with those should be under 1/2 inch. Otherwise ceilings should
gradualy lift through the afternoon with limited daytime heating.

&&

.BOU WATCHES/WARNINGS/ADVISORIES...
Winter Weather Advisory until 9 AM MST Friday for COZ031-033-050-
051.

&&

$$

UPDATE...Barjenbruch
SHORT TERM...Bowen
LONG TERM...Baker
AVIATION...Barjenbruch



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