829
FXUS65 KBOU 042043
AFDBOU

Area Forecast Discussion
National Weather Service Denver/Boulder CO
243 PM MDT Sat Oct 4 2025

.KEY MESSAGES...

- A few showers and storms with strong, gusty winds spreading
  across the northeastern plains into early evening. A threat of
  damaging winds of 60 mph or more with any of these.

- Another batch of showers Sunday night, with accumulating snow of
  a few inches becoming more likely (60%) in the northern Front
  Range Mountains and higher northern foothills.

- Much cooler Sunday through early next week...then warmer
  temperatures likely to return by mid/late week.

&&

.DISCUSSION /Through Saturday/...
Issued at 243 PM MDT Sat Oct 4 2025

Satellite shows a significant upper level trough lifting northeast
into Wyoming, with the trailing end of QG forcing moving across
the forecast area. The main batch of showers/storms is expected to
continue pushing eastward across the plains late this afternoon
and evening, bringing with them a threat of strong, damaging
winds. Strong mid level flow and a well mixed boundary layer with
pre-existing gusts to ~35 kts, means it won`t take much
acceleration to produce local storm scale severe winds of 50 kts
or greater. And, the existing DCAPE of 800-1200 J/kg on the plains
would be enough to support that so a couple severe storms still
expected mainly on the leading front of showers/storms. Most
showers/storms will exit rather quickly to the east and into
Nebraska and Kansas by 8-9 pm, with only a few showers lingering
in the high country this evening due to orographic forcing.

Of other note for tonight, there`s a window of strong mountain
wave induced winds for the foothills after the trough passage.
Earlier, there was a hint of a mean state critical layer and
higher threat of strong winds 01Z-04Z, but that chance has now
diminished. However, there is still a rather strong mid level
gradient combined with a more favorable stability profile 03Z-09Z.
Therefore, with 40 kts cross mountain flow we still expect some
60+ mph gusts over the higher foothills and eastern slope of the
Front Range mountains tonight, but shy of any High Wind Criteria.

For Sunday, we`ll see another frontal surge push across northeast
Colorado during the mid to late morning. This will usher in even
cooler air, with temperatures steadying out or even slowly falling
during the afternoon. Easterly anticyclonic upslope will deep
through Sunday afternoon and evening, leading to deepening
moisture profile and eventually saturation below 600 mb. As a
result, we expect precipitation to develop and expand in coverage
during this period, with the highest coverage in/near the Front
Range along/north of I-70. Snow levels also lower during this
period, and QPF amounts have increased a couple more tenths from
previous runs. We think the snow level will come down closer to
8,000 feet in the northern foothills, with at least some light
snow accumulations of a couple inches above that. Given the recent
trends, there`s a 60-70% chance that a few spots get several
inches of snow. This could cause some travel impacts for Trail
Ridge Road in Rocky Mountain National Park and Highway 14
approaching Cameron Pass.

The lower clouds, showers, and cool high pressure building in
through Sunday night means Monday will be quite chilly. At this
time, we expect a high probability (>80%) that high temperatures
only make it into the 50s across all of the plains and I-25
Corridor, and that could very well only be the lower to mid 50s!  We
probably won`t clear out that much or have too much low level
moisture for much of a frost threat for Monday night, but
nonetheless it will be quite chilly through this period.  There
should be just slight moderation by Tuesday.

The bigger warmup is still on track for the middle to end of next
week. There are some slight differences with weak embedded
shortwaves riding around the ridge, but overall there is good
agreement that general ridging occurs over the Central Rockies,
supporting a return of above normal temperatures and mostly dry
conditions.

&&

.AVIATION /18Z TAFS through 18Z Sunday/...
Issued at 1151 AM MDT Sat Oct 4 2025

Winds have steadily increased through the morning, with a
persistent southerly component in place across the TAF sites.
ACARS soundings show mixing is well underway with 35-40kt winds
measured at the top of the mixed layer. Still expecting convection
across the TAF sites this afternoon capable of producing VRB wind
gusts between 40-45kts. Hi-res guidance suggests one line of
storms will pass across the area between the 20-24Z time frame,
with winds diminishing after they depart to the east.

There are some uncertainties with what winds will do this evening
behind the line of convection. The current TAF depicts winds
shifting to the west and gradually weakening through the evening
before settling into drainage by 5/6Z. The latest hi-res guidance
is suggesting that there will be a more northerly push beginning
to make its way from north to south across the TAF sites around
1Z to 3Z before turning to drainage. If the northerly scenario
plays out, expecting winds to be much lighter (5-9kts).
Additionally, winds at KBJC may become more ESE and remain under
10kts between the 4-9Z if the westerly winds don`t win out.

&&

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

&&

$$

DISCUSSION...Barjenbruch
AVIATION...Bonner