382
FXUS65 KBOU 271204
AFDBOU

Area Forecast Discussion
National Weather Service Denver/Boulder CO
604 AM MDT Tue Oct 27 2026

.KEY MESSAGES...

- Areas of fog, some dense, across the plains and I-25 Corridor
  tonight into Tuesday morning.

- Warmer and mostly dry much of this week.

- Unsettled weather potentially returning late in the weekend and
  early next week, with a 20-30% chance of season`s first snow in
  lower elevations toward Tuesday.

&&

.UPDATE...
Issued at 535 AM MDT Tue Oct 27 2026

Dense fog has developed overnight across the plains, with
visibility dropping as low as 1/4 mile in some locations. A Dense
Fog Advisory is in place until 9AM for the I-25 corridor and
adjacent plains, and until 10AM for the northeast corner, with
hazardous travel conditions expected for the morning commute. Take
it slow out there and remember to use your low beams!

&&

.DISCUSSION /Through Monday/...
Issued at 1149 PM MDT Mon Oct 26 2026

It`s relatively quiet across the forecast area this evening. We`re
just starting to see the first bit of fog/mist develop across
Lincoln county, and stratus/mist has slowly developed along the
northwest Denver metro/northern I-25 corridor over the past couple
of hours. We still expect fog to become more widespread across the
plains overnight tonight, with some dense fog likely over portions
of the I-25 corridor later tonight through the AM commute Tuesday.
Some dense fog advisories may be needed overnight, but would like
to see the fog actually develop before trying to pinpoint where
the dense fog is compared to the less impactful low stratus.

Fog and stratus should erode pretty quickly during the morning
hours Tuesday. Like today, temperatures will be slow to warm up
during the day, with highs generally in the low to mid 60s -
potentially a bit cooler for the northern I-25 corridor.

The rest of the upcoming week looks quiet, as dry
west/southwesterly flow aloft continues. A return to a more active
pattern begins towards the end of this week or this weekend. A
weak but well-defined shortwave lifts north out of New Mexico
into the central Great Plains on Friday. It looks like this will
track just to the east of our forecast area, but there should be
an increase in cloud cover along with a chance of showers along
the far eastern plains, with better chances in Kansas/Nebraska.
Around the same time, some moisture from the Pacific reaches
western Colorado either Friday or Saturday, leading to some
scattered light rain/snow showers across the mountains to start
the weekend.

A stronger, more organized system could approach the region by
the end of the weekend into next week. A strong upper trough is
projected to crash southeastward towards our forecast area,
potentially interacting with the moist subtropical jet streak. As
the previous shift noted, there is quite a bit of spread across
guidance. Several of deterministic models over the last 12 hours
have advertised the idea of a stronger upper low moving across
Colorado, though many still remain rather quiet across the state
with a disorganized trough quickly moving through. Ensemble
guidance continues to show a wide distribution of solutions,
ranging from almost no precip in our CWA to some rather juicy (and
at times, snowy) scenarios. Within the ensemble distribution,
there has not been a significant trend in any direction. Given
that we`re still several days out, most of these cycle to cycle
changes are simply noise, and it will take some time before a
clear trend emerges. Still, it`s worth monitoring for the few
days in an otherwise quite forecast period.

&&

.AVIATION /12Z TAFS through 12Z Wednesday/...
Issued at 535 AM MDT Tue Oct 27 2026

Low visibility down to 1/4SM due to fog is expected to persist for
the next few hours at KDEN/KBJC before starting to improve between
14Z-16Z. KAPA has been able to hold onto some stronger southerly
winds that have kept it from getting any closer than within the
vicinity of the airfield. This should also start to retreat from
within the vicinity around 14-15Z.

For the rest of the day, a Denver Cyclone is expected to make for
another tricky wind forecast, but winds are expected to remain
light (under 8kts) through around 20Z-21Z. After that, there is
decent agreement amongst this morning`s hi-res guidance that we
see some slightly increased easterly winds (9-11kts) for the late
afternoon until the cyclone moves north and east of the TAF sites
and drainage winds likely set in at KDEN/KAPA (S-SSW). KBJC should
see light and variable winds for the majority of the overnight
hours, with southerly winds possible by early Wednesday morning.

&&

.BOU WATCHES/WARNINGS/ADVISORIES...
Dense Fog Advisory until 9 AM MDT this morning for COZ038>040-
042>047.

Dense Fog Advisory until 10 AM MDT this morning for COZ048>051.

&&

$$

UPDATE...9
DISCUSSION...Hiris
AVIATION...9

NWS BOU Office Area Forecast Discussion