712 
FXUS65 KBOU 132348
AFDBOU

Area Forecast Discussion
National Weather Service Denver/Boulder CO
548 PM MDT Tue Oct 13 2026

.KEY MESSAGES...

- Much cooler temperatures and wet conditions is still on track.

- Rain and mountain snow showers will become more numerous
  tonight, mainly west of I-25. More widespread rain and mountain
  snow still on schedule for Wednesday afternoon - Wednesday 
  night, before winding down Thursday. 

- Several inches (6-12") of snow expected for the mountains above
  9,000 to 10,000 feet with travel impacts late Wednesday thru 
  Thursday morning. Lighter snow and at least a dusting into the 
  mountain valleys and higher foothills. 

- Drier and warmer again for next weekend. 

&&

.DISCUSSION /Through Tuesday/...
Issued at 144 PM MDT Tue Oct 13 2026

Satellite imagery shows the upper level low diving southeast 
across Nevada. The low will bottom out over northern Arizona 
tonight and be centered over the Four Corners 18Z Wednesday. Water
vapor imagery and radar show an area of lift over eastern Utah 
and western Colorado, with widespread showers. This area of lift 
shifts eastward tonight bringing rain and mountain snow showers to
the western two-thirds of Colorado. Easterly low level flow will 
continue tonight and Wednesday around the low to our southwest and
a surface high to the north. Cross sections show that the low 
levels will become saturated overnight and Wednesday. This 
saturated layer becomes deep enough for drizzle late tonight and 
Wednesday. The upper level low tracks northeast across Colorado 
Wednesday afternoon through Wednesday night bringing widespread 
rain and high country snow. The best snowfall for the mountains 
comes later Wednesday and Wednesday night when flow becomes a 
favorable northwest direction (for orographic lift). We've issued 
a Winter Weather Advisory for the mountains where 6 to 12 inches 
of snow are expected. The snow level tonight will be 10,000 to 
11,000 feet dipping below 10,000 feet over the northern mountains 
towards sunrise Wednesday morning. Once the low moves over 
Colorado, the snow level falls to 8,000 feet around sunset 
Wednesday evening and 7,500 feet by Thursday morning.  Rain and 
snow linger into Thursday, especially across northern Colorado, 
wrapping up during the afternoon.  

Skies clear out around sunset Thursday night as a surface settles
over Colorado. This will bring the coldest night so far this 
fall. Many places will see a frost or freeze Thursday night and 
Friday morning. Overnight lows are on track to be in the upper 20s
to mid 30s over northeast Colorado. Typical low lying areas/cold 
spots are expected to fall into the mid to lower 20s.

An upper level high will be centered over the intermountain west,
with a closed low trapped beneath it off the coast of northwest 
Mexico on Friday. Cross sections show a very dry airmass, 
resulting in sunny skies all day on Friday. Cool air lingers with 
highs in the upper 50s to lower 60s, but light winds and sunny 
skies will make it feel warmer. The upper level ridge slides east 
of the region Saturday. Southwest flow aloft will prevail behind 
the ridge bringing warmer air to the area. Temperatures climb 
above normal with highs expected to reach upper 60s to lower 70s 
across northeast Colorado. 

A weak trough in the flow aloft tracks across the Central Rockies
on Sunday. It also absorbs the upper level low off the northwest 
Mexico coast.  Models indicate very little moisture will accompany
this trough, thus dry conditions are expected to continue Sunday.
Temperatures may take a small step back. 

Mild and dry conditions are expected for Monday and Tuesday as
southwest flow redevelops over the Central Rockies ahead of a
deepening trough along the west coast. This trough tracks eastward
mid to late next week bringing the next chance for rain, mountain
snow, and cooler temperatures.

&&

.AVIATION /00Z TAFS through 00Z Thursday/...
Issued at 538 PM MDT Tue Oct 13 2026

VFR conditions are expected this evening, before an extended
period of IFR/LIFR conditions tonight through Wednesday.

A few showers have developed across the foothills over the last
hour, which are attempting to push eastward into the Denver metro.
This largely matches output from high resolution guidance (though
the HRRR has struggled to place these properly)... and the general
consensus is that SHRA should become more widespread through
03-04z tonight. There should also be rapid development of low 
stratus between 03-06z, with IFR or LIFR cigs likely at the
terminals. There are some minor timing differences from this
afternoon's guidance but nearly all models have at least IFR cigs
by 06z.

Once stratus develops tonight, it will persist through the rest of
the TAF period, aided by consistent light easterly upslope winds.
Periods of rain are also likely tonight and Wednesday... with one
round expected overnight tonight and a more organized band of rain
possible Wednesday afternoon. 

&&

.BOU WATCHES/WARNINGS/ADVISORIES...
Winter Weather Advisory from noon Wednesday to 6 AM MDT Thursday 
for COZ031-033-034.

&&

$$

DISCUSSION...BM
AVIATION...Hiris