307
FXUS65 KBOU 140600
AFDBOU

Area Forecast Discussion
National Weather Service Denver/Boulder CO
1100 PM MST Fri Nov 13 2026

.KEY MESSAGES...

- Above normal temperatures and dry conditions will prevail
  today, followed by more seasonable temperatures this weekend
  into next week.

- Chances for rain and snow showers across the high country
  Saturday, with a few showers possible over the eastern plains.

- A more active storm track looking likely for next week.

&&

.DISCUSSION /Through Friday/...
Issued at 138 PM MST Fri Nov 13 2026

The persistent upper-level ridge that has been parked over the
region, keeping above-normal temperatures and dry conditions in
place, is finally beginning to shift eastward today. This will
establish a more favorable storm track for approaching systems,
essentially opening the door to a more active weather pattern
heading into next week.

The first of what looks to be three separate disturbances
expected to move across the western CONUS this week can be seen on
water vapor imagery as an open trough moving through SoCal and
Arizona early this morning. As this approaches, we will see a
transition to southerly flow aloft over Colorado as the day
progresses. Today`s afternoon high temperatures are on track to
reach the low to mid 60s across the plains, outside of where
morning fog has limited the sun from heating things up so far
today. Therefore, areas in our far northeastern corner and Lincoln
County will be slightly cooler than our more densely populated
areas along the urban corridor, where only some high cirrus are in
place. Our mountain valleys should see temperatures warm into the
low to mid 50s.

Moisture is expected to increase overnight tonight as the trough
nears, bringing an increase to cloud cover as the night progresses.
Across the lower elevations, fog is expected to develop late tonight
that may make for some hazardous driving conditions through the
morning on Saturday, and may lead to some impacts at DIA with
decreased arrival and departure rates possible for those with early
morning flights. Overnight low temperatures are forecast to drop
into the 30s across the plains, 20s for the higher elevations.

Light mountain snow showers are expected to develop through the
morning tomorrow, with scattered rain showers forecast to move over
the plains for the afternoon and overnight as latest guidance shows
the trough closing off and becoming a closed low over southeastern
Colorado. Snow amounts are not expected to be very impressive with
this first round of moisture, but a few inches (1-3") are expected
for elevations above 10,000 feet, with less than an inch forecast
for our mountain valleys. Areas over the Palmer Divide and into
Lincoln County will cool enough overnight Saturday that we may end
up with some flakes falling before sunrise on Sunday, with the best
chance for any light accumulations to be over the Palmer Divide. Fog
is expected to develop again late Saturday night across Lincoln
County before spreading northward across the eastern plains and
along the urban corridor, where it will gradually burn off through
the morning on Sunday. Outside of the morning fog, quiet weather is
expected to return across the forecast area for Sunday afternoon,
where temperatures are expected to warm back up into the mid to
upper 50s across the urban corridor.

A brief period of upper-level ridging is expected to return over the
region on Monday that will bring a slight warmup and drier
conditions for the first few days of next week. By midweek, a second
disturbance is expected to approach the Intermountain West, though
ensemble guidance continues to show considerable spread and little
consensus. This is evident in all of the GEFS/AIFS-ENS/AIGEFS
spaghetti plots, where 500mb height contours look more like an
actual plate of spaghetti than a clear lock on any particular
outcome. The same can be said for the third potential disturbance
that may arrive by the end of next week. While confidence remains
low at this time, this system has the potential to be the most
impactful of the three, bringing a more substantial cooldown and
perhaps even our first accumulating snowfall across the lower
elevations. There is still much to unpack, so stay tuned!

&&

.AVIATION /06Z TAFS through 06Z Sunday/...
Issued at 1100 PM MST Fri Nov 13 2026

A Denver cyclone will strengthen overnight, bringing a wind shift
to the northwest at DEN and BJC between 09Z and 11Z. Moisture
increases with the wind shift and fog is expected to develop an
hour or two after the wind shift. APA is expected to maintain a
more westerly flow, limiting the fog threat, but it will be close
if fog moves in. The fog is expected to persist through at least
15Z and could linger as long as 17-18Z. Increasing mid and high
clouds will likely slow warming and the dissipation of the fog.
Low clouds persist through Saturday across the plains, and there`s
a 30 percent chance they linger through the day at BJC and DEN if
winds stay a northeast direction. There`s also about a 30 percent
chance for rain showers 20Z to 03Z with ceilings dropping to 4000
to 6000 feet. For late Saturday night and Sunday, more low clouds
and fog are likely (60-70% chance) at DEN and BJC.

&&

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

&&

$$

DISCUSSION...9
AVIATION...BM

NWS BOU Office Area Forecast Discussion