508
FXUS65 KBOU 060714
AFDBOU

Area Forecast Discussion
National Weather Service Denver/Boulder CO
1214 AM MST Sat Dec 6 2025

.KEY MESSAGES...

- Scattered snow showers will continue across the mountains this
  afternoon with localized travel impacts over the high mountain
  passes. A brief break int the snow late this afternoon into the
  evening.

- Significant snow and wind event for the mountains begins tonight
  as snow redevelops. Heavy snow and gusty winds expected, with
  substantial travel impacts possible across most of the mountain
  corridors.

- Stronger winds at times into early next week.

- Milder temperatures ahead, with above normal temperatures by
  early next week.

&&

.SHORT TERM /Through Saturday/...
Issued at 232 PM MST Fri Dec 5 2025

Mountain snowfall has overperformed today. Several ski resort snow
stakes have recorded over 6 inches of snow today, and CDOT webcams
have also seen periods of moderate snow and travel impacts across
portions of the I-70 corridor. At least a couple more hours of
snow showers is expected this afternoon before drier air (as seen
by water vapor satellite imagery) works back into the region by
the early evening hours. However, this will be short lived as a
more impactful wave of snowfall arrives a few hours later.

The first significant winter storm of the season is expected to
reach the forecast area by late this evening as a plume of deeper
moisture arrives. Model cross sections are quite favorable for
orographic snowfall, with moisture depths reach 400mb in a well-
aligned west-northwesterly flow. We`ll also have some upper level
support as a 140kt upper jet streak slowly sinks south tonight
into Saturday. While the mountains will see the more significant
snowfall totals, it looks likely that light to moderate snowfall
will also spread into the high mountain valleys by Saturday
morning. Moisture gradually diminishes during the daytime, but
there should be enough lift from the upper jet to at least keep a
few bands of snow around through most of the day. HREF mean/PMM
QPF totals through 00z Sunday are generally around 1-2" for the
Park Range and 0.75-1.5" for the Front Range and Summit County
mountains. Snowfall ratios will likely be a little lower than
climatology would suggest with this storm due to initially warm
temperatures and impacts from the wind (more on that below), but
snowfall totals should range from 4-10" across the mountain
valleys, 7-15" across the I-70 mountains, and 1-2 feet over the
Park Range. One thing worth watching is if guidance is a little
too dry with QPF for the latter half of the day... which could
lead to some localized totals up to 30" in favored terrain.

Perhaps more impactful than the snow will be the wind with this
event. A 75kt 500mb speed max tracks almost directly over the
mountains Saturday... with even stronger flow closer to 350-450mb.
With subsidence increasing behind the passage of a weak shortwave,
we should see widespread strong wind gusts develop during the late
morning to early afternoon hours. Guidance is in reasonably good
agreement advertising gusts of 35-50 mph across the mountain
valleys and 50-75 mph gusts across the mountain passes. Depending
on how much overlap there is between the moderate/heavy snow and
the increasing winds, there could be a period of near blizzard
conditions across portions of the high country. We`ve expanded the
Winter Storm Warning into Middle Park and issued a Winter Weather
Advisory across North Park due to the potential for snow and
blowing snow there.

Across the plains, dry but breezy conditions should develop during
the afternoon as mid-level flow and subsidence increase. Guidance
favors wind gusts of 30-50 mph across the metro and plains. A few
rain or snow showers may attempt to make it across the mountains
during the day but chances for measurable precipitation remain
quite low (034.

&&

$$

SHORT TERM...Hiris
LONG TERM....12
AVIATION...Danielson

NWS BOU Office Area Forecast Discussion