249
FXUS65 KBOU 280613
AFDBOU

Area Forecast Discussion
National Weather Service Denver/Boulder CO
1213 AM MDT Wed Oct 28 2026

.KEY MESSAGES...

- Another night of fog with visibility below 1/4 mile in the South
  Platte River Valley and the far eastern plains of Colorado.

- Mild and mostly dry through the work week.

- Unsettled weather potentially returning late in the weekend and
  early next week. There are many scenarios for how the weather
  will turn out but snow in the mountains is the most likely
  impact from this system. One possibility results in the lower
  elevations seeing their first snowfall of the season.

&&

.DISCUSSION /Through Tuesday/...
Issued at 124 PM MDT Tue Oct 27 2026

Current observations show areas of fog over parts of the northeast
CO plains. A Dense Fog Advisory is currently in effect for Sedgwick
and Phillips counties, where visibilities have dropped below 1/2
mile. The Dense Fog Advisory may have to be extended later tonight
as the fog continues to expand west, with patchy fog reaching as far
west as Greeley. Subsidence and a patch of mid level clouds should
limit fog potential over the Denver metro. We expect fog to diminish
by mid morning due to daytime heating, with the South Platte River
valley likely clearing last.

Cross-barrier (west-southwest) flow will make Wednesday quite a
breezy day, particularly early in the day as mountain wave and
downsloping enhancement occurs. Wind gusts up to 35 mph will be
possible at the high elevations, with gusts up 55 mph possible above
12,000 ft MSL. Temperatures will run above average for the plains
and Denver metro, with highs reaching the upper 60s and low 70s. If
an opaque mountain wave cloud is able to persist into the afternoon,
as was seen on Monday, temperatures could stay a couple of degrees
cooler for areas directly under the cloud cover. Flow aloft weakens
and turns southwesterly on Thursday. Winds should remain light due
to the weakening pressure gradient, and this should be a sunny fall
day with temperatures only slightly above normal for the time of
year.

Moisture from the remnants of Tropical Storm Vance will be advected
north into our region on Friday. However, the bulk of the moisture
should remain well to our south and east, mainly over the Texas
Panhandle and central Plains. We have kept some 15-30% PoPs over the
easternmost counties of our CWA, where some light rain seems
reasonable late Friday evening. For the rest of our area, an
increase in high clouds may be all that transpires as a result of
this first plume of moisture.

Moisture remains elevated on Saturday, with precipitable water (PW)
values generally between the 75th and 90th percentile of climatology
over much of the state. A shortwave trough should bring enough QG
ascent for a few sprinkles (15-25% chance) over the eastern CO
plains, and rain/snow showers over the mountains (30-50% chance) in
the afternoon.

The synoptic pattern becomes more complex on Sunday as an upper
level trough and a subtropical jet approach the Four Corners. The
subtropical jet is set to channel impressive Pacific moisture to
parts of Arizona and New Mexico, akin to an atmospheric river. At
this time, the bulk of the moisture plume appears to stay well to
our south once again. Southwest flow aloft may still bring
anomalous moisture to north-central CO, although this regime would
primarily favor downsloping, which is not ideal for meaningful
precipitation over the mountains of our CWA or the Denver area.
Nevertheless, cloud cover and at least some light rain seems
increasingly likely for Sunday, with light snow above 10,000 ft
MSL.

A strong cold front is set to bring below average temperatures on
Monday, with model guidance suggesting quite a bit of spread in
solutions. With lingering moisture over the area, some mountain
snow accumulations are becoming increasingly likely during the day
on Monday. While a few deterministic and ensemble members do
hint at least some dustings or light snow accumulations over the
Palmer Divide and parts of the Denver metro, ensemble means
suggest temperatures that would not be supportive of snow
(40s-50s). This will be a system to watch as snow levels are
likely to reach the foothills.

&&

.AVIATION /06Z TAFS through 06Z Thursday/...
Issued at 1118 PM MDT Tue Oct 27 2026

VFR conditions expected to prevail for all terminals through the
TAF period. Latest guidance has backed off the westward extent of
stratus early Wed AM, and have thus removed the VCFG mention from
the TAFs. Expect light and variable winds after ~16Z Wed,
transitioning to E/SE winds early to mid afternoon, before
returning to drainage flow in the evening.

&&

.BOU WATCHES/WARNINGS/ADVISORIES...
Dense Fog Advisory until 10 AM MDT Wednesday for COZ050-051.

&&

$$

DISCUSSION...AA
AVIATION...BRQ

NWS BOU Office Area Forecast Discussion