014
FXUS65 KBOU 011933
AFDBOU

Area Forecast Discussion
National Weather Service Denver/Boulder CO
133 PM MDT Thu Oct 1 2026

.KEY MESSAGES...

- Dry and unseasonably warm weather returns for the majority of
  the week ahead. Record/near record warmth next Monday.

- A few showers expected Monday night and Tuesday as a weak
  disturbance moves across.

&&

.DISCUSSION /Through Thursday/...
Issued at 133 PM MDT Thu Oct 1 2026

Much quieter weather will prevail through the next several days.
An upper level ridge begins to build into the state tonight as
the last storm system exits and weakens to the east. This means
clearing skies and cool autumn temperatures (coolest of the season
so far). However, a return southerly flow of moisture and hybrid
advection/radiation will mean some patchy fog/low clouds over
portions of the plains. For the most part, these should be
confined to the south facing slopes of the Palmer Divide and
Cheyenne Ridge, but a weak cyclone also supports a risk of patchy
fog along the I-25 Corridor north of Denver to Fort Collins. A
true autumn-like night is expected with lows dipping into the 40s
across the plains, and mid 20s to mid 30s in the mountains and
high valleys.

Temperatures on Friday will warm to above normal levels under the
ridging, with the strongest warmup along the I-25 Corridor. Highs
for metro Denver should push 80F, while inversions will still be
a little stronger farther east on the plains with generally upper
60s to mid 70s. Most foothills and high valleys should also reach
the upper 60s to mid 70s, and mostly 50s to mid 60s in the higher
mountains. On Saturday, we`ll tack on several more degrees for
the lower elevations due to improved mixing, despite the passage
of a weak front. No precipitation is expected with a dry autumn
airmass dominating underneath the ridge.

Slight moistening occurs in the column for Sunday into Monday,
with an isolated shower or weak storm possible over the high
country. While temperatures would likely slip a couple degrees in
the post-frontal airmass for Sunday, the dominating ridge means
more unseasonable warmth returning by Monday with highs forecast
into the mid to potentially upper 80s across the plains. There is
excellent agreement amongst the ensembles there, which means we`ll
be approaching record highs by next Monday (Denver`s record is
87F set in 2024).

A weak disturbance is still set to move across the state Monday
night and Tuesday, which will offer up slight cooling and a chance
of light showers. However, the persistence of the flat ridge
combined with weak downslope flow will support a continuation of
above normal temperatures and a return of dry weather for the
latter half of next week.

&&

.AVIATION /18Z TAFS through 18Z Friday/...
Issued at 1142 AM MDT Thu Oct 1 2026

Fairly straightforward looking TAFs for most of this period, but
monitoring a slight chance of fog impacts early Friday morning.

For the short term, ACARS and observations show moisture generally
at or above 11,000 ft MSL, while satellite shows gradual clearing
from the north. While we`ll likely see some redevelopment of
strato cu with daytime heating, for the most part it appears it
will only be SCT above 5,000-6,000 ft AGL. We do think the
majority of any BKN redevelopment and ILS requirements would be
confined to south of KDEN. Skies will clear by 00Z. North-
northeast winds will become more easterly 20Z-00Z, and then SE-S
with an enhanced southerly component by 03Z-06Z.

For overnight, we do expect enough radiational cooling for hybrid
advection/radiation fog development. Since it`s in almost due
southerly flow, we expect this mostly over the south facing
slopes of the Palmer Divide and Cheyenne Ridge. However, a weak
cyclone/shear zone is still expected to develop, but it should be
slightly farther north than typical. That means the main threat
of any fog/stratus would remain north of KDEN, but enough threat
on the fringe of the weak cyclone to bring fog to the vicinity
northwest of KDEN. Thus, we`ll have a couple hours of VCFG in the
TAF 12Z-15Z, but probability of direct impacts to the airport are
only about 20%.

&&

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

&&

$$

DISCUSSION...20
AVIATION...20

NWS BOU Office Area Forecast Discussion