393
FXUS65 KBOU 160024
AFDBOU

Area Forecast Discussion
National Weather Service Denver/Boulder CO
524 PM MST Mon Dec 15 2025

.KEY MESSAGES...

- Warm and dry through Tuesday, with breezy conditions tonight
  into Tuesday for the foothills and mountains.

- Remaining warm Wednesday with strong winds expected west of I-25.
  A High Wind Watch has been issued for Wednesday late morning
  through Wednesday evening.

- Near-critical to critical fire weather across portions of the
  foothills and plains on Wednesday. A Fire Weather Watch will
  be in effect from late Wednesday morning through early
  Wednesday evening.

- Friday may see critical fire weather conditions across portions
  of the plains and urban corridor.

- Light mountain snow potential Wednesday into Thursday and Friday
  into the weekend.

&&

.SHORT TERM /Through Monday/...
Issued at 302 PM MST Mon Dec 15 2025

Current satellite imagery shows mostly clear skies across the
forecast area. Temperatures are about 15 to 20+ degrees above normal
on the plains, ranging between low and high 60s, with a few stations
in the southern Denver metro reaching low 70s. We have officially
tied our record high temperature for DIA (68 set in 1921), and won`t
be surprised if we are able to warm up another degree or two to
break the record. Other than that, quiet conditions prevail for the
mountains and plains this evening and tonight.

It will be warm and mostly dry on Tuesday as upper level flow
flattens due to a shortwave trekking south of Colorado. With
increased flow aloft, expect breezy conditions along the high
terrain and areas off the Cheyenne Ridge. Cross-sections do indicate
moisture embedded in the flow, so can`t rule out a snow shower in
the northern mountains and an isolated light rain shower or two in
the northern plains and foothills, particularly in the morning.
For the rest of the day, downsloping winds will create elevated
fire weather conditions (see Fire Weather Discussion below) and
allow temperatures to rise into the mid-to-high 60s again. While
unlikely, we do have the potential to break the max temperature
(70 degrees set in 1980).

&&

.LONG TERM /Tuesday night through Monday/...
Issued at 302 PM MST Mon Dec 15 2025

Strong winds will return to the mountains and potentially the
I-25 corridor on Wednesday. The mid and upper level flow will
increase along the Front Range Wednesday morning and into the
afternoon. Winds are forecast to peak Wednesday afternoon and
evening with cross barrier flow around 60 to 70kts at mountain
top. Wind gusts in the higher elevations could approach 90 mph at
times Wednesday afternoon. The soundings from the global models
are missing a critical layer and the inversion above ridge top is
not at the ideal level for a downsloping event, both of which will
hinder the winds ability to push eastward into the lower
foothills and surrounding plains. However, some of the higher res
models, like the RRFS, are starting to show both a critical layer
and inversion, which helps increase our confidence that stronger
winds could move further east into the I-25 corridor Wednesday
afternoon. Also, a few ensemble members of both the GEFS and
European are showing gusts in the 60 to 75mph range in the
foothills and at the base of the foothills. We`ll get a better
idea on the potential for the winds to push further east as the
high res models continue to come in and we`ll continue to keep an
eye on the potential for a critical layer and inversion.

Another thing to watch for Wednesday is the cold front moving in
from the northwest Wednesday evening and overnight. Just ahead of
the front, we could see mountain wave enhancement, which would help
give the winds the extra push they need to reach Boulder and west
metro Denver. As the front moves in, the winds will turn from a
chinook event into more of a bora event, with decent northwest winds
behind the front. Right now, winds behind the front look to stay
around 20 to 30mph with gusts around 40mph. However, the GFS does
keep winds a bit higher behind the front, with some sustained speeds
closer to 40mph. Temperatures will be cooler and much closer to
normal for Thursday afternoon thanks to the front.  RH is expected
to drop to 15-20% across the I-25 corridor.  With the potential for
high winds several hours Wednesday afternoon, there are significant
fire weather concerns covered in in the fire weather discussion
below.

Winds will pick back up Thursday night into Friday. Wind gusts at
higher elevations could be in the 70 to 90mph range again Friday
morning. Once again, we have lower certainty in how far east the
stronger winds will push. Right now, we`re keeping the stronger wind
gusts (50+mph) generally above 7000ft. With the downsloping winds
again on Friday, temperatures will warm back up to potentially
record breaking highs. Weaker downsloping winds and the approach of
a low pressure system and cold front will keep temperatures a few
degrees cooler for the weekend, but highs will remain well above
normal.

Now onto precip chances. The mountains will have a few chances at
snow this week. The first round will be associated with the strong
west upslope flow, decent moisture, and frontal passage Wednesday
into Thursday. The higher elevations of the Front Range and Park
Range could see a around 2 to 6 inches of snow, with some higher
amounts on the peaks. The foothills and plains also have a chance of
precip with the frontal passage, but chances will be low (<30%) and
it should be primarily lighter rain amounts. The next chance for
precipitation in the mountains will be Friday through Sunday. The
Front and Park Ranges could see an additional few inches with this
activity.

&&

.AVIATION /00Z TAFS through 00Z Wednesday/...
Issued at 444 PM MST Mon Dec 15 2025

VFR conditions to persist through the TAF period. Winds are
currently beginning their transition back to the southeast early
this evening, with decreasing speeds expected to take hold once
they settle into a southerly component for the overnight hours.

Expecting winds to make a gradual transisition to the NE at
KDEN/KAPA through the morning Tuesday, with westerly winds
expected to remain at KBJC, with 20-30% chance the westerly winds
gust 25-35 kts between 12Z-16Z at KBJC.

&&

.FIRE WEATHER...
Issued at 302 PM MST Mon Dec 15 2025

Strong downsloping winds and marginal relative humidity values
will lead to near critical to critical fire weather Wednesday
afternoon. Minimum RH values will be around 15 to 30% in the
foothills and the plains. Wind gusts Wednesday afternoon could
approach 60mph at times in the I-25 corridor. Winds will be
lighter and RH higher on Thursday, limiting fire weather
potential. Winds will increase into the 15 to 30mph range for
Friday. Minimum RH values Friday will drop to 13 to 25%, leading
to elevated to near- critical fire weather. Smoke dispersal
conditions will be Fair to Very Good for the West Slope mountain
valleys Wednesday through Saturday.

&&

.BOU WATCHES/WARNINGS/ADVISORIES...
High Wind Watch from Wednesday morning through Wednesday evening
for COZ033>036-038-039.

Fire Weather Watch from Wednesday morning through Wednesday
afternoon for COZ238>240-242-243-245.

&&

$$

SHORT TERM.....12
LONG TERM...AP
AVIATION...9
FIRE WEATHER...AP