495 
FXUS65 KBOU 270632
AFDBOU

Area Forecast Discussion
National Weather Service Denver/Boulder CO
1232 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. 

&&

.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 /06Z TAFS through 06Z Wednesday/...
Issued at 1149 PM MDT Mon Oct 26 2026

Uncertainties remain in the forecast for the next few hours as we 
are right on the verge of fog developing across our northern two TAF 
sites (KBJC just got there at the time of this writing), with 
dewpoint depressions hovering between one to two degrees at 
KDEN, and winds just reaching low enough speeds to increase fog 
development chances. Additionally, low stratus have already been 
advecting southward along the foothills of Larimer and Boulder 
Counties, having just gotten to KBJC airfield. While KDEN keeps a 
more southerly component we will have lower chances of the stratus
making their way into the airfield, but with some northerly winds
observed just north of KDEN, have moved up the timing of VCFG to 
the prevailing, as at this time, satellite nighttime microphysics
shows it steadily approaching the ten mile radius of KDEN's 
airfield, with KEIK showing ceilings down to BKN006 and KBJC now 
showing 1/4SM VIS and FG. KAPA continues to hold onto much 
stronger and slightly more SSE east winds that should keep them 
out of seeing fog or the low ceilings while this persists, but 
will still remain a wildcard if winds can manage to turn away from
their southern component or slow in speeds, which some guidance 
does show possible sometime between the 9Z-11Z time frame. 
Overall, the highest chances for the fog becoming more widespread 
still look good for the 9Z-10Z to 14-15Z time frame, with things 
looking to start clearing out between 15Z-16Z. 

With regards to Tuesday, winds are expected to be light and
variable through the morning before becoming easterly and
increasing in speeds between 21Z-22Z (10-12kts) at KDEN/KAPA, with
KBJC likely holding onto a lighter and more northerly component
through the afternoon and evening. 



&&

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

&&

$$

DISCUSSION...Hiris
AVIATION...9