535
FXUS65 KBOU 240113
AFDBOU

Area Forecast Discussion
National Weather Service Denver/Boulder CO
613 PM MST Fri Jan 23 2026

.KEY MESSAGES...

- Arctic air now over the forecast area and to continue in place
  into Monday morning, with below zero wind chills for the
  plains.

- Areas of light snow for the plains late Friday night into
  Saturday morning.

- Mountains to see 4 to 12 inches of snow through Saturday,
  heaviest along and south of I-70.

- Second round of light snow (with accumulations 0.5-3") Sunday
  afternoon and evening for most areas.

- Warming trend returns Monday, with mostly dry and more seasonal
  conditions through the rest of the work week.

&&

.SHORT TERM /Through Saturday/...
Issued at 206 PM MST Fri Jan 23 2026

As expected, it`s cold. Temperatures across the foothills and
plains are generally in the single digits to mid 10s. Wind chill
values are near zero across most of the I-25 corridor and are a
bit lower across the northeast plains. The cold spot of our CWA is
currently an AWOS station northeast of Briggsdale in northeastern
Weld county, where the current temperature is a balmy 0F and the
wind chill is currently -22F. Across the metro, the most notable
feature is a persistent, well-defined Denver cyclone that has
helped produce some very light snow across the Denver metro most
of the day. While we have sufficient near-surface moisture, snow
has been limited by a very strong inversion near 700mb... which is
clearly evident in ACARS soundings today. Finally, snow is
gradually beginning to develop across the mountains. Boundary
layer moisture across the higher elevations is less impressive at
the moment but has been steadily improving through the day.

The general story in the short term period has not changed
significantly. As the shortwave and the accompanying mid-level
front sink southward this evening, moisture depths should increase
dramatically... leading to more widespread light to moderate
snowfall across the mountains. The better lift is still expected
to be along/south of the I-70 mountains tonight. Across the metro,
we`ll likely see a bit more coverage of snow late this evening
through the first half of Saturday morning. I suspect forecast QPF
is a little too low in some places where there could be some
enhanced convergence/upslope from the Denver Cyclone. With
dendritic growth zone depths as deep as around 9-10kft, it
wouldn`t be surprising to see someone in the I-25 corridor come in
with a few inches of very fluffy (high SLR) snow... though most
should only see around an inch.

The moisture axis should shift southward following the departing
shortwave, leading to a gradual decrease in snow from north to
south over the CWA. There`s still some question as to how quickly
we clear out during the day - and how much we manage to warm up as
a result - but in general forecast models haven`t changed
significantly in this period. Our afternoon forecast package was
generally a couple degrees cooler than the previous but did not
lead to any real changes to the overall forecast message.

&&

.LONG TERM /Saturday night through Friday/...
Issued at 206 PM MST Fri Jan 23 2026

Cold temperatures will remain anchored in place Saturday night,
trending colder in the high country given some fresh snow cover and
at least partial clearing, and conversely trending marginally
"milder" along the base of the foothills and I-25 corridor under
weak downslope flow. This flow should allow for locally moderated
daytime temperatures Sunday where west/southwest winds are more
persistent, but an approaching cold front will keep it limited in
scope and duration.

A second and quite robust shortwave will emerge over Montana
Saturday night, accelerating south through the day and driving a
cold front through northeastern Colorado beginning near midday
Sunday. Subtle timing uncertainty with the front reduces confidence
in Sunday`s high temperature forecast, especially for the southern
half of our forecast area where the frontal passage may be more
closely aligned with typical peak heating. In any case, parts of the
northern plains are unlikely to break out of the teens, while areas
roughly along and south of I-70 (outside of our mountains) look to
warm into the 20`s.

The likelihood of accumulating snow with/following Sunday`s front
has risen notably over the past 24 hrs, driven mostly by strong low-
level frontogenesis. Moisture amounts are relatively meager across
the board however (generally 0.05-0.15" of QPF for the mountains,
foothills and I-25 corridor, with upper-end potential of ~0.20" for
the most favored locations in/near the foothills), although healthy
lapse rates and cold temperatures will favor higher snow ratios of
15-20:1 providing a slight boost to accumulations. All that said,
expecting most of the region to see between 0.5-2" of snow, with
localized accumulations to 3" being within reach west of I-25,
falling almost entirely in the afternoon and early evening. Snow
will taper off from north to south and end by midnight. Sunday night
is progged to be the coldest of this arctic stretch thanks to the
frontal reinforcement, fresh snow, and rapidly clearing sky
conditions. Have thus opted to extend the Cold Weather Advisory
through Monday morning, when wind chill values of -10 to -20F will
be relatively widespread across the plains. It will be a
particularly cold night in our high valleys, with low temperatures
falling below -15F in the typical cold pool locations. Breezy winds
Sunday into Monday will also sustain very low wind chills in our
mountains including during daytime hours.

Seasonal temperatures and dry weather make a quick return by Monday
as the shortwave exits to our east and is replaced by weaker
northwest flow aloft and broad subsidence. The warming trend is set
to continue through midweek, with some stabilization as we enter the
latter half of the week. There is no indication of a significant
shift to our predominantly dry pattern through the first week of
February, with ensembles widely favoring generally dry conditions
regionwide and only punctuated by low chances for light mountain
precipitation, the first of which is centered around Thursday night-
Friday night.

&&

.AVIATION /00Z TAFS through 00Z Sunday/...
Issued at 558 PM MST Fri Jan 23 2026

The stratus clouds will not be going away for at least another 18
hours at all terminals. The majority of time this evening will be
spent with MVFR ceilings at all terminals. Snow is expected to
increase in intensity tonight but will still remain light overall.
Visibility down to 1 SM is expected between roughly 08-16Z with
the most likely time from 10-14Z. Snow will decrease throughout
the morning and visibility will return to P6SM around 17-18Z.

The most difficult part of the forecast is when the stratus clouds
will clear Saturday afternoon. Oftentimes in arctic airmasses, the
low clouds have a tough time clearing out. So there is uncertainty
in the forecast but the most likely time for VFR conditions to
return is between 20-23Z.

As for winds, a Denver cyclone will be persistent near DEN for
much of the night. The cyclone will most often be just to the east
of the airport so light northerly winds are expected. Overall wind
speeds will be very light throughout the TAF period.

&&

.BOU WATCHES/WARNINGS/ADVISORIES...
Winter Weather Advisory until 5 PM MST Saturday for COZ034.

Cold Weather Advisory from midnight Sunday night to 9 AM MST
Monday for COZ038-043.

Cold Weather Advisory until 9 AM MST Monday for COZ042-044>051.

&&

$$

SHORT TERM...Hiris
LONG TERM...BRQ
AVIATION...Danielson

NWS BOU Office Area Forecast Discussion