105
FXUS65 KBOU 302037
AFDBOU

Area Forecast Discussion
National Weather Service Denver/Boulder CO
137 PM MST Tue Dec 30 2025

.KEY MESSAGES...

- Lower elevations remaining warm and dry through this weekend,
  with minor day-to-day temperatures fluctuations.

- Dry and mild pattern in the mountains will be interrupted
  Thursday afternoon into Friday, with light snow expected.
  Greatest potential for travel impacts will be in and near the
  Park Range.

&&

.DISCUSSION /Through Tuesday/...
Issued at 105 PM MST Tue Dec 30 2025

The tranquil weather pattern will continue into Wednesday as the
ridge axis expands into the Western Slope, pushing highs into the
lower 60`s for most of the plains/urban corridor and 40`s for our
mountain valleys. With this forecast, Denver is projected to wrap
up the month with its second warmest December on record, with
other Front Range locations including cities such as Dillon,
Boulder or Fort Collins making a run for top warmest December.

The mountains remain on track for a spell of winter weather
beginning Thursday afternoon and continuing through Friday, as the
ridge flattens and allows for a weak wave to advect some increased
moisture into the high country. Most of the snow will be
orographically-forced, generally limiting accumulations outside of
the more favored Park Range, where between 3 and 10" of
accumulation is expected. The I-70 corridor will be more hard-
pressed to see anything as significant, although minor
accumulations will still be capable of impacting travel over the
passes. Snow ratios will be on the lower end of what is typical
for the mountains given the warmer temperatures, and we may even
see more of a wintry mix at times for the valleys during the
warmer hours of the day Friday.

A weak front Thursday evening/night will brush the plains and
allow for slight cooling there, but the impact will diminish with
proximity to the I-25 corridor where downslope flow should dampen
the cooling effect and sustain above-average temperatures. There`s
slim potential for a few drop of rain or a wintry mix across the
Cheyenne Ridge with this feature, but with frontogenesis lacking,
precipitation potential for the lower elevations will be close to
zero during this period.

Transient ridging will move in for Saturday, for warm and dry
conditions regionwide. That looks to give way to a more zonal flow
pattern aloft for Sunday onwards, and increased southwest winds
with an approaching modest jet. Ensembles become much noisier at
this point with varying indications as far as jet positioning/wind
strength, moisture availability etc. Close to or slightly over
half favor a return of wetter conditions to our high country
(note: not the lowlands), and a similar proportion suggest
potential for enhanced downslope winds Sunday into early next
week, which could leave the door open to some fire weather
concerns under the warmer and drier scenarios (which the GEFS
HDWI control member alludes too). Either way, an uncertain pattern
past Saturday.

&&

.AVIATION /18Z TAFS through 18Z Wednesday/...
Issued at 1014 AM MST Tue Dec 30 2025

VFR conditions to persist through the TAF period. Current light
and variable winds will transition to the east by 20-21Z across
the TAF sites. Expecting generally light winds through the
overnight hours, with only some slight enhancement (10-12 kts)
with drainage winds after around 6Z.

A similar wind pattern is expected for tomorrow morning, with some
uncertainties concerning wind directions for the afternoon as an
anticyclone develops. Despite uncertainties with direction, winds
are expected to remain generally light (under 10 kts) as high
pressure dominates over the region. Guidance currently suggests an
E to ESE direction will develop by ~20Z, but this could easily
change depending on where the anticyclone sets up.

&&

.BOU WATCHES/WARNINGS/ADVISORIES...
None.

&&

$$

DISCUSSION...BRQ
AVIATION...9

NWS BOU Office Area Forecast Discussion