786
FXUS65 KBOU 182344
AFDBOU

Area Forecast Discussion
National Weather Service Denver/Boulder CO
544 PM MDT Sat Oct 18 2025

.KEY MESSAGES...

- Widespread freeze expected for the rural plains and northern
  I-25 corridor Saturday night.

- Warmer Sunday with a slight reprieve in winds, but low humidity
  will keep fire weather conditions near critical.

- Another potent front arrives early Monday, bringing light
  mountain snow north of I-70, widespread strong winds, and
  critical fire weather conditions.

- Lighter winds will more seasonal temperatures Tuesday onward.
  Potential for some showers Wednesday night and Thursday, with
  best chances in the mountains.

&&

.DISCUSSION /Through Saturday/...
Issued at 148 PM MDT Sat Oct 18 2025

To the relief of many, winds have begun to ramp down for all areas
after this morning`s potent cold front. Still, we`ll hold onto
breezy conditions over the plains and mountains the rest of the
day, before the gusty winds subside more noticeably for the lower
elevations overnight. We saw a hefty temperature drop of 10 to
as much as 20 degrees, so it`s no surprise we`re still on track
for a relatively widespread freeze tonight across the plains. If
winds are able to calm sufficiently, some patchy freezing
conditions will likely also extend into traditionally colder
outlying areas of the Denver metro, mainly to the north.

The thermometer will bounce back Sunday as high pressure drifts
overhead, leading to a mild and dry day across the board. While
cross-barrier flow will remain near 45-50 knots and thus sustain
breezy conditions over the higher mountain terrain, we`ll see a
notable reprieve for the lower elevations in the absence of any
mountain wave amplification mechanism. Opted to cancel Sunday`s
Fire Weather Watch given these marginal wind conditions, although
still suspect we will see short spurts of localized fingers with
25-30 mph gusts over the urban corridor which will promote near-
critical conditions.

In true Fall fashion, the wind won`t take long to make a
reappearance. A jet max will arrive on Monday as an amplifying
trough clips the state, driving another potent cold front south
early morning. With the jet in place and healthy frontogenesis,
there`s a greater potential for some mountain snow accumulation
(mainly north of I-70) compared to this last system, though
amounts should still be on the minor side (~1-3"). Precipitation
elsewhere looks to be very limited, however the NBM`s 0% PoPs for
Monday morning don`t quite capture the potential that inherently
accompanies these frontogenic setups, so did introduce some slight
(15%) PoPs into the forecast for the plains and urban corridor.
The front will pack a punch, with gusts expected to hit 50 mph
over the plains and 40-45 mph for the urban corridor. Its passage
also looks early enough to allow for ample drying by the
afternoon and, with post-frontal winds remaining gusty, critical
fire weather conditions can be expected for much of the lower
elevations. A Fire Weather Watch has thus been issued, mainly for
areas south of I-76 where fuels are the most susceptible. Highs
will fall back below seasonal averages and into the 50`s and
lower 60`s for the lowlands.

Both temperatures and winds will moderate midweek (Tuesday into
Wednesday) as this trough exits eastward, replaced by weaker zonal
to slightly northwest flow aloft. By Wednesday night, a lifting closed
upper-level low will approach from the southwest and drift over
Colorado into Thursday. Ensembles have been fairly consistent in
showing a favorable track for at least some light mountain
snowfall. QG lift and potentially some brief northeasterly upslope
flow may promote a few showers for the urban corridor and plains
as well, favoring areas south and west of Denver, although
temperatures will generally be too warm to support snow for the
lower elevations. Drier conditions with seasonal temperatures
look to prevail as the low pushes east Friday into Saturday.

&&

.AVIATION /00Z TAFS through 00Z Monday/...
Issued at 536 PM MDT Sat Oct 18 2025

VFR conditions through the TAF period. Relatively light NE winds
will persist through the evening before turning SE by 02Z/03Z and
then drainage overnight.

Light winds will gradually turn W for all TAF sites. BJC could see
a stronger westerly push up to 15-20 kts by 20Z due to downslope
winds.

&&

.BOU WATCHES/WARNINGS/ADVISORIES...
Fire Weather Watch from Monday morning through Monday afternoon
for COZ216-239>241-245>247-249.

Freeze Warning from 10 PM this evening to 8 AM MDT Sunday for
COZ038-041>051.

Frost Advisory from 10 PM this evening to 8 AM MDT Sunday for
COZ039-040.

&&

$$

DISCUSSION...BRQ
AVIATION...MAI