652
FXUS65 KBOU 270514
AFDBOU

Area Forecast Discussion
National Weather Service Denver/Boulder CO
1014 PM MST Fri Dec 26 2025

.KEY MESSAGES...

- One more mild day across lower elevations on Saturday before a
  cold front brings much colder temperatures Saturday night.

- The northern mountains will see snow beginning tonight and
  lasting through Sunday morning. The heaviest snow amounts will
  be in the Park and Gore Ranges where a Winter Storm Warning is
  in effect. Moderate amounts are expected across the Front Range
  mountains with a Winter Weather Advisory in effect.

- Lower elevations will see light snow Saturday night into Sunday
  morning, and there is a high amount of uncertainty. Anywhere
  from 0-3" of snow expected, but local banding up to 5" still
  possible in a couple spots.

&&

.DISCUSSION /Through Friday/...
Issued at 240 PM MST Fri Dec 26 2025

Water vapor imagery shows shortwave troughs over northern
California and northwest Washington state with a broader trough
over the western US. These shortwave troughs will combine and move
into Colorado Saturday night into Sunday. Ahead of this trough, a
stream of Pacific moisture will move into far northern Colorado
tonight. This will bring snow to the Park Range mountains and the
Winter Storm Warning begins at midnight tonight as a result. A lot
of that moisture will miss the Front Range Mountains tonight and
Saturday morning so PoPs and QPF amounts are on the lower side
there. It is not until around midday Saturday that better
moisture and orographic flow arrives in the Front Range Mountains
that snow will begin there. Therefore, a Winter Weather Advisory
was issued starting at 11AM. Strong frontogenesis ahead of the
shortwave trough will create bands of moderate to heavy snow in
the mountains Saturday afternoon through Saturday night. Travel
will be poor to hazardous especially Saturday night when the sun
sets and road temperatures decrease below freezing. Orographic
snow showers will continue through midday in the mountains before
coming to an end. Storm total snowfall amounts are expected to be
between 8-18 inches in the Park and Gore Ranges and 4-12" in the
Front Range.

Across the I-25 corridor and eastern plains, Saturday will be mild
with highs in the upper 50s to low 60s. A strong cold front at
the surface will move across the plains shortly before midnight
near the Wyoming border and around 2-4 AM near the Palmer Divide.
Behind the front, northeast winds will develop which will create
upslope flow. That low level forcing will combine with the upper
level forcing from the PVA ahead of the trough and the mid level
frontogenesis to create a couple brief bands of snow that will
spread across the area. The latest ensemble guidance has decreased
the QPF and snow amounts slightly. Roughly 0.10-0.15" QPF is
forecast on the east side of the I-25 corridor with between
0.15-0.30" on the west side of the I-25 corridor. The snow amount
forecast was decreased slightly for the eastern I-25 corridor with
1-3" now forecast. The western I-25 corridor is still expected to
receive 2-5" of snow. Across the eastern plains, 0-2" of snow is
forecast with the highest amounts around Akron to Last Chance.
Due to the uncertainty, no winter weather highlights were issued
at this time. However, highlights may be needed especially for the
Sunday morning travelers which are expected to encounter poor
road conditions.

Snow will end Sunday around midday with clearing skies. Single
digit to low teen lows are forecast across the plains.

Colorado will be on the eastern edge of a ridge aloft late Monday
through the rest of the work week. This will lead to dry
conditions with warming temperatures. Highs in the 50s are
forecast Tuesday through Friday across the plains. The next chance
for precipitation will be next weekend for our forecast area.

&&

.AVIATION /06Z TAFS through 06Z Sunday/...
Issued at 1014 PM MST Fri Dec 26 2025

VFR will persist through at least 06Z Sunday. Then areas of snow
expected to develop with MVFR/local IFR. Winds have transitioned
to a fairly normal south/southwest and are expected to hold through
about 18Z Saturday. After that, more uncertainty enters the
picture. Most short range higher resolution models bring a
stronger westerly component to the TAF sites by 18Z, while other
guidance is later or remaining VRB. We think the cirrus should be
thin enough to allow for mixing, and thus we`ve opted to go more
westerly with gusts around 20-24 kts possible but starting closer
to 20Z at KDEN and KBJC. KAPA could see them as early as 17-18Z,
and they`ll also have a chance of gusts >25 kts. Winds are then
most likely to turn west/northwest by 00Z in prefrontal mode, and
eventually north/northeast post initial weak front/surge by
03Z-04Z Sunday. A strong cold front will likely arrive by 06Z,
with lower ceilings and bands of snow behind it.

&&

.BOU WATCHES/WARNINGS/ADVISORIES...
Winter Storm Warning until 5 AM MST Sunday for COZ031.

Winter Weather Advisory from 11 AM Saturday to 11 AM MST Sunday
for COZ033-034.

&&

$$

DISCUSSION...Danielson
AVIATION...20

NWS BOU Office Area Forecast Discussion