808
FXUS65 KBOU 230617
AFDBOU

Area Forecast Discussion
National Weather Service Denver/Boulder CO
1217 AM MDT Fri Oct 23 2026

.KEY MESSAGES...

- Warm, dry, and breezy on Friday.

- Cooler weather returns this weekend with chances for rain. An
  overall drying trend emerging for most of the Denver metro and
  I-25 corridor.

- A cool start to next week, but a warming and drying trend likely
  by mid-week.

&&

.DISCUSSION /Through Thursday/...
Issued at 1125 PM MDT Thu Oct 22 2026

A deep plume of moisture extends from south central Colorado into
western New Mexico at the time of this AFD, and significant
rainfall totals have been reported across much of southwest and
southern Colorado over the past 24 hours. In our forecast area,
there`s been some scattered showers across the mountains and over
the eastern plains (mainly Lincoln and Washington counties),
though precipitation amounts have been very light so far. Guidance
does attempt to push some of that more organized precipitation
into our forecast area overnight, but the terrain blocking and
downslope off the Front Range will likely prevent any meaningful
rainfall from falling. The NAM is the only real exception to this
but doesn`t appear to be a very realistic scenario. A few light
showers will continue at times overnight with mostly cloudy skies
across the forecast area.

Friday will likely end up as the warmest (and breeziest) day of
the week, as the primary shortwave associated with the trough to
our west will lift off to the northwest. The flow aloft should
shift to a southwesterly direction, finally shunting the deeper
moisture plume off to the east of the state and advecting in the
much drier airmass currently over Arizona. There would still be
just enough moisture aloft to support a couple virga showers in
our forecast area, but most of the day will feature partly cloudy
skies. Mid-level temperatures will still be warm and the weak
subsidence and downslope should promote highs in the mid 70s to
mid 80s across most of the lower elevations. A broad lee trough
extending from Denver through eastern Wyoming will keep winds a
bit lighter for the northern I-25 corridor, while most of the
Denver metro and eastern plains see some gusts of 30-40 mph during
the afternoon hours. While we will see a drying trend, relative
humidity values should remain high enough to avoid any critical
fire weather conditions during the afternoon hours.

Saturday will feature quite the change from this period of warmer
weather. A cold front still looks likely to arrive just after
sunrise on Saturday morning, with steady northeast surface winds
expected through the day. As mentioned in numerous forecast
discussions prior to this one, a cutoff low is expected to develop
over the desert southwest (near the CA/AZ border) and lift into
southeast Utah by late Saturday night. We`ll see another period of
moisture advection into the area with stronger south-southwest
flow redeveloping during the day, leading to an increase in cloud
cover and chances for showers by late Saturday afternoon. Guidance
continues to hint at a near-surface dry layer that would prevent
significant precipitation across most of the mountains and
adjacent plains, with better chances for rain across far eastern
Colorado in the better warm air advection/isentropic lift Saturday
evening/night.

There is a bit more uncertainty for Sunday, as guidance begins to
split into two scenarios. Most of the extended range CAMs and
regional models keep moisture/stratus across the forecast area,
while some deterministic guidance (ECMWF) advects a drier airmass
back into the region. Those drier solutions are much warmer with
highs back in the 60s... while the moist/stratus solutions would
keep highs closer to 50F. The current forecast is a bit of a
compromise with a slight preference towards the cooler solutions
at this time. The upper low is expected to shear out as it lifts
through our forecast area Sunday night, but this could provide
another period of weak ascent... and guidance generally attempts
to produce some light rain and snow showers over the region Sunday
night into Monday morning.

Monday will be cool but generally dry in the wake of the trough,
with light flow aloft. The flow should turn southwesterly and
begin to strengthen by Tuesday or Wednesday ahead of the next
western CONUS trough. That approaching trough could lead to
another period of cooler/unsettled weather across the state by
late next week or next weekend... but that falls outside our
current forecast period.

&&

.AVIATION /06Z TAFS through 06Z Saturday/...
Issued at 1125 PM MDT Thu Oct 22 2026

Current observations show that some light rain showers have
finally held together enough to bring a few drops to KAPA late
tonight. Light rain will continue to be possible for the next few
hours, generally for KAPA/KDEN with KBJC seemingly slightly less
favored. Ceilings could drop as low as BKN060-BKN070 with any
passing showers for the next few hours (through 8Z-9Z). Gusty
south to southwesterly winds are expected to persist at KDEN/KAPA
through the day on Friday, with latest hi-res guidance showing
potential for a slight decrease in speeds at KAPA from 13Z-15Z
(down to 15-20kts) before increasing back up to 25-30kt gusts
through 0Z. KBJC is expected to remain slightly more sheltered
from the stronger gusts for the overnight period, with light south
to southeasterly winds likely through the morning, before
increasing around 18Z. Ceilings could drop as low as BKN060-BKN070
with any passing showers for the next few hours

A cold front is expected to pass over the TAF sites on Saturday
morning just outside of this TAF period. We should start to see
some lowering ceilings at the tail end of this TAF period (11-12Z),
but impactful CIG aren`t expected until the next TAF period, where
we are expecting CIG to drop to ~BKN050-BKN070 sometime late
Saturday morning.






&&

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

&&

$$

DISCUSSION...Hiris
AVIATION...9

NWS BOU Office Area Forecast Discussion