941
FXUS65 KBOU 242342
AFDBOU

Area Forecast Discussion
National Weather Service Denver/Boulder CO
542 PM MDT Sat Oct 24 2026

.KEY MESSAGES...

- Cooler and unsettled for the rest of the weekend. A couple
  rounds of showers, one late this afternoon and evening and
  another tomorrow late afternoon through the night.

- Some snow accumulation (considerable spread in potential
  accumulations) for mountains above 9,000 feet, but generally
  minor travel impacts expected over the high mountain passes.

- Warming trend and mostly dry much of next week.

- Unsettled weather potentially returning next weekend.

&&

.DISCUSSION /Through Saturday/...
Issued at 116 PM MDT Sat Oct 24 2026

Satellite shows a broad upper low over the Desert Southwest with a
couple of embedded vorticity maximums circulating around it, the
most pronounced one in southwest Arizona. This latter feature
will end up being the main low which will drift slowly northeast
into eastern Utah on Sunday. Ahead of that, weak lift will be
present both from the QG aspect and an upper level speed max
ahead of this trough. One wave of energy is currently organizing
with a considerable amount of convection in southwest and south
central Colorado, and that will arrive late this afternoon/
evening as it advects north/northeast in the mean flow. While our
instability is marginal and S/SW flow is generally downslope for
us, the earlier frontal passage has brought deepening upslope to
about 11,000 ft MSL east of the Front Range. That will help offset
the substantial drying we`ve seen in this flow pattern over the
last couple days, and thus showers will have a greater chance of
surviving as they roll off the higher terrain and onto the plains
and I-25 Corridor. We`ve bumped PoPs up just a tad thanks to the
upslope component. We still think most precipitation amounts will
be light (0.10-0.20 inch or less), although the Mosquito Range and
south facing mountains along the Summit County/Park County line
including Hoosier Pass could easily pick up 3-5" of snow with some
travel impacts through this evening. Snow amounts tonight would
taper off rather quickly along/north of I-70 to just an inch or
so. One other location that stands a higher chance (30-60%) of
more meaningful precipitation near 0.5 inch rain would be over the
far eastern plains, roughly east of a line from Holyoke to Limon.

On Sunday and Sunday night, synoptic scale lift will gradually
increase as the upper level low moves east across the forecast
area. Models were still highly variable, with the synoptic scale
models still pointing toward better chances of more widespread
showers than today. However, we will be fighting a deeper
downslope component than today, as flow just off the deck is more
southerly. The only upslope component would be quite shallow and
north of a Denver Cyclone. Thus, the highest chances of rain late
Sunday afternoon and especially Sunday night will likely shift
toward the northern half of the forecast area. Probabilities of
>0.50" of rain are 30-50% near the Wyoming/Nebraska border, with
much lower probabilities farther south. In the mountains, snow
levels will likely hover near 9,000-10,000 feet which would
support a few more inches of snow for the high country. Again,
that favors the northern tier of mountains so another 1-5" is
expected there, but some high end solutions still show a small
chance (10-15%) of as much as 8-10".

By Monday morning, there is good agreement that the upper trough
will be moving east and northeast of the forecast area, taking the
precipitation with it. Temperatures will start to moderate with
Monday`s highs pushing back into the 60s for the lower
elevations. We`ll turn to a more zonal flow Tuesday which means
further warming and mostly dry weather, although a couple of the
ensemble members have just enough moisture for a few rain/snow
showers in the northern mountains.

Wednesday through Friday are shaping up to be dry and warmer as
southwest flow aloft and flat ridging develops across the
forecast area. Highs could push back to near 70F as ensembles
continue to trend to a warmer solution.

We`re still watching the next potential trough and/or return of
subtropical moisture as we head toward next weekend. While there
is considerable uncertainty in the details, it does appear we are
shaping up for more unsettled weather but again quite a bit of
blocking by the southern CO mountains.

&&

.AVIATION /00Z TAFS through 00Z Monday/...
Issued at 542 PM MDT Sat Oct 24 2026

Local radars showing light rain showers moving north across the
airfields. Coverage will continue to be spotty and rain itself
intermittent this evening. Expect the rain to move out or
dissipate by 04/05Z. Zero chance of lightning. We don`t expect any
VIS issues, but CIGs should be in the 025 to 030 range now
through around 12Z. Winds should remain around 10 kts at DEN,
going from currently about east to southeast by 04Z. Light winds
under 7 kts at APA and BJC should go to southeast after 04/05Z as
well, 5-8 kts.

CIGS should become VFR or close to VFR after 12Z tomorrow at all
terminals. Worst case they remain BKN030 to 040 through 16 or 17Z,
but that`s probably a 20% chance of happening. Winds will be
squirrelly but 7-12 kts with a Denver Cyclone in the area after
16Z. BJC should go north after 12Z and stay that way, per usual.
APA could be variable or south at 10 kts much of the morning
through 20Z. The cyclone may be just north and west of APA
through 18Z making the wind forecast tricky. By late afternoon
south is likely as the cyclone moves well north of APA. For DEN, a
period of VRB should follow SW winds, roughly 18-21Z but hard to
pin down the typical 2-3 hour period when winds are from all
directions but light. After 21Z, the cyclone should be north and
east of DEN resulting in northwest winds at DEN. CAMs are showing
a 40-60% chance of rain showers after 23Z, so we put a TEMPO in
the DEN TAF after 00Z. We`ll likely need to do the same at BJC and
APA for the 06Z TAFs. CIGs with those rain showers are expected
to drop to as low as BKN020.

&&

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

&&

$$

DISCUSSION...20
AVIATION...Schlatter

NWS BOU Office Area Forecast Discussion