Brainard Lake Trail, Colorado Weather Forecast Discussion

736
FXUS65 KBOU 201115
AFDBOU
Area Forecast Discussion
National Weather Service Denver/Boulder CO
515 AM MDT Sat Sep 20 2025
.KEY MESSAGES...
- Seasonal temperatures for the weekend, with a chance of diurnal
  showers/storms mainly over the mountains.
- Cold front Monday with a good chance of showers late Monday,
  remaining cool with scattered showers Tuesday. High mountain
  snow likely Monday night into Tuesday.
- Turning warmer and drier again late next week.
&&
.DISCUSSION /Through Friday/...
Issued at 150 PM MDT Fri Sep 19 2025
High clouds continue to spread across the area this afternoon. Mid
level moisture will increase by Saturday, but low levels will
remain dry. There should be enough instability for scattered
showers/storms over the mountains, but the cloud cover will be a
limiting factor. It`s possible a few showers might drift off the
mountains late in the day. Sunday looks similar, there may be some
decrease in moisture from the west in the afternoon but that could
actually promote more shower activity with some sunshine.
The models continue to trend further southwest with the
Monday/Tuesday shortwave, though there`s quite a range in
solutions from northeast of us to southwest of us. In any event,
it looks likely that the cold pool aloft with this system will
pass over our area and bring some instability. A direct shot could
produce a period of rainfall late Monday followed by more mundane
showery weather Tuesday. If the system passes on either side of us
this could just be one clump of showers, and then some low grade
showers over the next day or two but in a somewhat stable air
mass. The NBM continues to trend upward with PoPs focused on
Monday afternoon and evening, and is bringing the impacts west of
the Front Range. It`s cold enough for snow above timberline, and
possible down to 9 or 10 thousand feet depending on where the
coldest air aloft goes. There`s still some discrepancy on plains
temperatures, but there are more runs keeping us in the 60s on
Tuesday now. We should get at least a 10 degree drop. It`s likely
too cloudy/windy for any frost threat Tuesday morning, but a few
coldest spots on the plains could have frost Wednesday. Most areas
will likely stay in the 40s.
After that system departs, we`ll be on the east side of a strong
ridge. Northerly flow aloft may slow our warming trend, but we
will likely be back close to seasonal normals by Thursday or
Friday.
&&
.AVIATION /12Z TAFS through 12Z Sunday/...
Issued at 510 AM MDT Sat Sep 20 2025
Winds have become light SW at DIA but light variable at APA and
BJC. Winds will become more NNE by 18z and then turn more easterly
by 21Z.  Still can`t rule out a chc of high based showers and
possibly an isold tstm by 22z. However, have kept in a prob30 for
-shra for now. Winds will gradually become more southerly by 03z
 and then may trend more SW by 06z. There will be abundant mid and
 high clouds moving across but ceilings should be mainly above
 12000 ft. If showers develop could see brief ceilings down to
 9000 ft thru 03z.
&&
.BOU WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
DISCUSSION...Gimmestad
AVIATION...RPK

NWS BOU Office Area Forecast Discussion