862
FXUS65 KBOU 081142
AFDBOU

Area Forecast Discussion
National Weather Service Denver/Boulder CO
442 AM MST Thu Jan 8 2026

.KEY MESSAGES...

- Snow is expected to increase in coverage this morning and
  continue at times through Friday morning. Heaviest snowfall
  across the Front Range mountains and foothills today,
  potentially spreading into the Palmer Divide tonight.

- Winter Weather Advisories across most of the higher elevations
  including the Palmer Divide through late Friday morning.
  Trending less snowy, especially for the Denver metro along and
  north of I-70.

- Much colder for Thursday and Friday, with highs in the 30s.

- Moderating temperatures this weekend, with dry weather
  prevailing through early next week.

&&

.UPDATE...
Issued at 349 AM MST Thu Jan 8 2026

Shallow upslope flow continues to develop across the region this
morning. Both HRRR analysis data and KFTG VAD profiles suggest
that there`s roughly 10-15kt upslope through ~650mb this
morning... a good sign for those hoping for snow. The bad news?
there is a substantial amount of sfc-700mb dry air, and surface
T/Td spreads still sit near 20-25F this morning. It is clear that
we`re slowly moistening the column... as ceilings heights have
dropped a few thousand feet over the past few hours. Across
portions of the higher foothills, snow is beginning to fall,
though at this time it`s been fairly light.

What comes next? Guidance is in somewhat better agreement
regarding how the rest of the day`s snowfall potential plays out.
As the strengthening lee cyclone and its 700mb low track from
southeastern Colorado into northwestern Kansas this morning, that
should leave a period of at least modest upslope flow across the
I-25 corridor during the morning hours. Recent RAP/HRRR runs
produce at least some light snow across the foothills and I-25
corridor during the morning hours though impacts will be limited
by low/mid 30s surface temperatures. The upslope component weakens
and moisture diminishes a bit as the lead low races into the upper
Midwest, but at least a few snow showers should continue through
most of the afternoon hours with rather steep lapse rates aloft.
Total snow accumulation today is expected to be a a couple of
inches over the mountains and foothills with under an inch for the
lower elevations.

The forecast gets less clear this evening into Friday morning. The
second 500mb shortwave is expected to reach the Four Corners
region by 00-06z this evening, with a secondary mid-level low
developing over northern New Mexico in this timeframe. A secondary
push of colder air along with briefly deepening northerly upslope
may aid in the development of heavier snow rates along the
southern Foothills and Palmer Divide as the mid-level low
strengthens. ECMWF ensemble mean QPF in this period has actually
increased a bit... and joins a few other models that are bullish
in this period. However, the better QG ascent and mid-level
convergence is likely to set up well south of our CWA. Given the
continued run-to-run/model-to-model inconsistencies, confidence
remains quite low in this period.

Total snowfall forecast have been nudged down again, and lie
fairly close to the ECMWF ensemble and HREF mean. This means
generally about 1-4 inches across the Denver metro, 3-9" over
most of the higher elevations, and generally less than an inch or
two for the northern I-25 corridor. The previous Winter Storm
Watch was upgraded to a Winter Weather Advisory (with slightly
delayed timing) while the rest of the highlights were unchanged.
Further adjustments to the forecast and winter weather products
may be needed if any obvious near term trends emerge this
morning... but in general, the drier/less impactful storm
scenarios are looking increasingly likely.

&&

.DISCUSSION /Through Wednesday/...
Issued at 413 PM MST Wed Jan 7 2026

Today will be the last day of the week that we will see dry
conditions and above normal temperatures, as ridging aloft gets
pushed east by the two incoming systems. However, despite being 24
to 36 hours out, there are still some uncertainties and large
model spread with the evolution of the two shortwaves.

Current satellite imagery shows the first shortwave in Baja
California and the second one off the coast of the Pacific
Northwest. We expect the lead shortwave to eject into the Great
Plains by late Thursday morning, with moisture wrapping around the
700-mb closed low and favorable upslope flow aiding in rain/snow
mix (transitioning to snow) across the forecast area Thursday
morning and afternoon/evening. However, model trends have
continued to indicate unfavorable low-level NNW flow seeping in,
particularly for the northern foothills and plains. This will
promote downslope flow and dry air intruding into the plains,
which will inhibit snowfall amounts. The question is, how far will
the drier NNW flow make it? That will depend on the track of the
upper level low. There is a large spread in QPF amounts between
models due to this uncertainty, but consensus is that southern
Front Range/foothills and Palmer Divide will most likely receive
the best potential for accumulating snowfall.

The second shortwave will trek across northern New
Mexico/southern Colorado sometime Thursday night/Friday morning.
This will lead to another opportunity for widespread snowfall
across the area through Friday morning due to upslope flow.
However, this system will be battling stronger dry air intrusion
from the north. How much snow will we get with the second system?
That question again depends on the track of the 700-mb low, if we
get unfavorable NNW flow vs. favorable ENE flow. By late Friday
morning, any snowfall should diminish, with drier spreading across
the region.

Despite these uncertainties, we still think the majority of the
region will receive snowfall, with highest amounts confined to the
southern Front Range mountains (for the high country) and lower
foothills/Palmer Divide (for the lower elevations). Have opted in
for Winter Weather Advisories for the mountains and southern
foothills, with snowfall accumulations between 4-10 inches (lower
end in the northern mountains due to the unfavorable flow), with
localized higher amounts. In addition, added a Winter Storm Watch
for the Palmer Divide, with snowfall accumulations between 5-10
inches and the potential for localized higher amounts if we can
get stronger upslope flow. For Urban Corridor/Denver and east
still think 2-4" (less in the northern and northeastern plains) is
likely. However, there is a 10-20% chance for higher amounts (5+")
if the ingredients can come together.

Behind these systems, expect warmer and drier conditions as an
upper level ridge sets up in the southwester United States.
Temperatures will begin to rise above normal starting Sunday, with
forecasted highs in the 50s once again.

&&

.AVIATION /12Z TAFS through 12Z Friday/...
Issued at 432 AM MST Thu Jan 8 2026

Ceilings continue to gradually lower this morning. Modest upslope
is in place with reflectivity aloft also starting to gradually
lower. Guidance suggests that we`ll see MFVR cigs and some snow as
soon as 13z, continuing through around noon today before
transitioning to widely scattered snow showers. There is still
some potential for a more organized burst of snow later this
afternoon into tonight, especially at APA.

I continue to have low confidence in nearly aspect of the TAF, as
there is still considerable variability across guidance for wind
direction, ceilings, and snowfall potential through 12z Friday. In
general, MVFR to IFR conditions are anticipated through a majority
of the TAF period with winds out of the north to northeast.

&&

.BOU WATCHES/WARNINGS/ADVISORIES...
Winter Weather Advisory until 11 AM MST Friday for COZ031-033-
034.

Winter Weather Advisory until 11 AM MST Friday for COZ036.

Winter Weather Advisory from 2 PM this afternoon to 11 AM MST
Friday for COZ041.

&&

$$

UPDATE...Hiris
DISCUSSION...MAI
AVIATION...Hiris

NWS BOU Office Area Forecast Discussion