898 
FXUS65 KBOU 130424
AFDBOU

Area Forecast Discussion
National Weather Service Denver/Boulder CO
1024 PM MDT Mon Oct 12 2026

.KEY MESSAGES...

- Change in the weather to cool, wet conditions is still on track.

- Showers will become more numerous in and near the mountains late
  Tuesday and Tuesday night, but then more widespread rain and
  mountain snow still on schedule for Wednesday - Wednesday night,
  before winding down Thursday. 

- Several inches of snow expected for the mountains above
  9,500-10,000 feet with some travel impacts late Wednesday -
  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 Monday/...
Issued at 1018 PM MDT Mon Oct 12 2026

An upper level low will be over central Nevada by 12z Tue and then 
will move to near the Four Corners area by 12z Wed.  Will gradually 
see a better chc of showers along with a few tstms by Tue aftn in 
the mtns.  Across the plains, cooler temps will occur behind a front 
as weak upslope flow develops.  Highs will drop into the lower to 
mid 60 across nern CO. Any chc of showers by late aftn will be 
confined to areas closer to the foothills.

By Tue night, will see widespread showers across the higher terrain 
with snow levels lowering to 9500 ft overnight.  Across the plains, 
best chc of showers overnight will be mainly along the I-25 Corridor 
with lessor chances further east.

For Wed thru Wed night, the main question is where will the upper
level low track, as it begins to move from swrn CO east northeast
towards ern CO. The Canadian, ECMWF and NAM have a more northern 
track as it moves into nern CO by 12z Thu. Meanwhile, the GFS has 
a more southern track with the upper level low being over east 
central CO. Looking at ensemble data from the ECMWF and GFS shows
a more northern solution with the low being over nern CO. 
Meanwhile, sfc high pres will continue to build into nern CO with 
the low level flow becoming ESE. Overall, with favorable QG ascent
should continue to see showers/isold tstms over the higher 
terrain thru the aftn with snow levels down to 9000 ft by late 
aftn. Across nern CO, should see showers thru the aftn, especially
along the I-25 Corridor with a chc across the plains. Highs on 
Wed, will only be in the mid 40's to lower 50's over nern CO.

By late Wed night into Thu, additional precipitation will depend on 
the exact track of the upper level low.  If it takes a more northern 
track across nern CO, then best chc of precipitation will be across 
the higher terrain along and north of I-70 and over nrn portions of 
the plains.  Naturally, if it were to take a more southern track 
across east central CO, then much of the area would have additional 
widespread precipitation late Wed night thru middday Thu. Meanwhile 
snow levels Wed night into Thu morning may drop down to 8000 ft or 
so. At this time, snow amounts look to be mainly in the advisory 
range for mtn areas, except over the higher peaks which may have 
higher amounts.

For Thu aftn into Thu night, the upper level low will weaken and 
move east of the area. Thus, will see precipitation gradually end
during the aftn hours in most areas. Highs on Thu will be in the 
50's across the plains. For Thu night into Fri morning, some areas
across the plains may see freezing temps with frost possible in 
those places that don't get down to freezing. 

Looking ahead to Fri and Sat, an upper level ridge will develop over 
the area.  This will lead to dry conditions with a warming trend. 
Highs will rise into the upper 50's to mid 60's on Fri, over nern 
CO, and then into the lower to mid 70's by Sat.   

On Sun, a very weak upper level trough will move across the area. 
Latest cross-sections show very little moisture associated with this 
feature. Thus it will remain dry with above normal temperatures. 

&&

.AVIATION /00Z TAFS through 00Z Wednesday/...
Issued at 642 PM MDT Mon Oct 12 2026

Winds are expected to stay predominantly south/southwesterly with 
gusts up to 20-25kts for the next several hours, through around 05Z, 
after which they should start to turn more northerly. Guidance is 
still in good agreement about low stratus moving into the area 
tonight, with ceilings starting to drop after 05Z. Ceilings are 
expected to lower to ~1,000-2,000 ft AGL at all three TAF sites and 
be at their lowest between 12-15Z. As of the latest model guidance, 
KDEN could see ceilings as low as 500 ft AGL (40-60% chance), with 
mist and slightly reduced visibilities also possible (40% chance) at 
the surface. Should any visibility reductions occur, we don't 
anticipate them to be any less than 4-5 SM, and we do not currently 
expect any visibility reductions KAPA or KBJC.

Ceilings should start to lift in the morning, around 17-18Z, with 
winds becoming more northeasterly. Winds should remain light and 
north/ northeasterly throughout most of the day, becoming more 
easterly with ~20-kt gusts behind the passage of a cold front in the 
afternoon. Thanks to this frontal passage, we could see some light 
precipitation over the area Wednesday evening, with the highest 
chances at KBJC starting at around 22Z.

&&

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

&&

$$

DISCUSSION...RPK
AVIATION...AGS