506
FXUS65 KBOU 010620
AFDBOU

Area Forecast Discussion
National Weather Service Denver/Boulder CO
1220 AM MDT Sun Nov 1 2026

.KEY MESSAGES...

- Areas of fog again through Sunday morning across portions of
  northeast and eastern Colorado.

- Unsettled weather returns late Sunday through early
  Tuesday.Mountain snow is likely (>70% chance) above 8500ft
  during thistime, with a few inches of snow expected.

- Scattered rain showers and cooler temperatures for the plains on
  Monday. A few snowflakes possible for the Palmer Divide on
  Monday night.

&&

.DISCUSSION /Through Saturday/...
Issued at 1204 AM MDT Sun Nov 1 2026

Current satellite imagery shows some mid-level clouds as well as
some patchy fog in Morgan County, eastern Elbert County, and
northern Lincoln County. Areas of dense fog or low stratus look
possible once again through this morning for northern Colorado and
along/near the Palmer Divide. This fog could make it as far south
as the northern Denver metro and east to DIA. Still some
questions about how widespread and/or dense the fog will be...A
Dense Fog Advisory may be needed later this morning if confidence
increases through the overnight. Otherwise, lows tonight will stay
in the 40s in the plains and 20s and 30s for the high country.

Sunday will be another nice afternoon with high temperatures in
the 60s for the plains, but there will be more clouds compared to
Saturday. Some wind gusts of 20-30 mph are possible in the
afternoon mainly across the eastern plains. Southwest flow aloft
through at least Monday midday continues to bring rich moisture to
our area. The trough to our west looks to move rather quickly
from the Great Basin on Sunday afternoon to eastern Colorado by
Monday evening. A low looks to form in southeast Colorado on
Monday evening, but the strongest energy continues moving off to
the northeast. At the surface, a cold front is progged to move
through early on Monday morning and make it through our southeast
counties by Monday afternoon. Therefore, temperatures on Monday
afternoon do not look to warm up very much from the low 50s and
possible even falling into the upper 40s on the plains. Have
nudged Monday afternoon temperatures down based on the latest
short-term guidance. Monday afternoon also looks windy for most of
the plains with some gusts of 30-40 mph and isolated wind gusts
up to 50 mph. Only slightly lower wind gusts are still possible
through Tuesday for the eastern plains.

In terms of precipitation: Light rain/snow showers should move
into the high country on Sunday afternoon with widely scattered
light rain showers by the evening for the plains given the
unfavorable southwest flow aloft initially. Snow levels look to
start rather high on Sunday afternoon (> 12,000 ft) and then
quickly drop by Sunday evening into the overnight to around 10,000
feet. We expect a further decrease in snow levels to 8,500 to
9,000 feet by Monday afternoon. Therefore, snow becomes
increasingly likely above about 8,500 to 9,000 ft for late Sunday,
through Monday, and lingering into early Tuesday morning. The
northern mountains look most favored for the higher snowfall
amounts in our area. Given the current snowfall forecasts and
limited scope of the heaviest totals, we have held off on issuing
a Winter Weather Advisory. One may be needed in a future forecast
package. The north flow behind the front introduces an upslope
component for the Palmer Divide where QPF could be maximized on
Monday evening. As we get into Monday night and early Tuesday
morning, colder air continues to filter in, so snow levels could
drop low enough (down to about 7,000-7,500 ft) for a few flakes on
the Palmer Divide. No snow accumulation is expected there given
the decreasing precipitation chances. Overall, we have slightly
increased QPF from the previous forecast for the next 48-60 hours
for locations in the high country and Palmer Divide.

Some ridging moves in for Tuesday with temperatures rebounding
into the upper 50s to low 60s for the plains. Another trough moves
through on Wednesday with another round of precipitation possible
though the signal for this remains murky. Some snow looks
possible again for the high country with rain showers possibly
spilling onto the plains once again. At this time, have low PoPs
for this potential starting Wednesday evening.

Once this system moves through, northwest flow aloft looks to
hold for Thursday and Friday keeping highs in the upper 50s to low
60s for the plains. Another cold front is possible as we get to
the weekend with unsettled weather looking to return as well.

&&

.AVIATION /06Z TAFS through 06Z Monday/...
Issued at 1204 AM MDT Sun Nov 1 2026

GOES nighttime microphysics RGB shows the edge of a fog/stratus
deck slowly drifting westward across Adams and Weld county. This
should continue to advect to the west-northwest over the next few
hours, but should remain north of the terminals where drainage
winds have managed to develop.

Main period of uncertainty comes later this morning, as guidance
pushes fog from north to south back into the Denver metro near
12z. Recent trends from the HRRR would suggest several hours of
1/4SM FG at BJC, while DEN remains very close to the edge. Did not
make significant changes to the previous TAF as it largely
reflects this, but it`s possible we end up seeing a longer period
of FG than the current TAF suggests. Any fog/stratus should clear
between 16-18z.

By the afternoon guidance develops some stronger southerlies at
DEN/APA, with a shear zone setting up closer to BJC. Southerlies
should prevail through most of the afternoon and evening, though
that boundary/shear zone may eventually push east of I-25 near
00z. Drainage winds are likely to start Sunday night, but there
are hints of more fog potential again by Monday morning.

&&

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

&&

$$

DISCUSSION...MV
AVIATION...Hiris