548
FXUS65 KBOU 152146
AFDBOU

Area Forecast Discussion
National Weather Service Denver/Boulder CO
246 PM MST Sat Nov 15 2025

.KEY MESSAGES...

- Well above normal temperatures through Sunday.

- Weak storm system still on track to bring mainly light snow to
  the mountains late Sunday into Monday, with generally minor
  travel impacts Sunday night to early Monday morning.

- Watching potential for a stronger early season storm next week,
  but considerable uncertainty. It will be cooler through the week
  ahead.

&&

.DISCUSSION /Through Saturday/...
Issued at 245 PM MST Sat Nov 15 2025

One more warm day is on tap for Sunday before the weather pattern
changes to a cooler and more unsettled regime.

Our current upper level ridge will shift east Sunday as the upper
low off SoCal opens up and lifts northeast into the Great Basin.
This will keep the mild airmass in place for one more day, and
there should be more sunshine as upper level moisture and
cloudiness decreases by early Sunday morning. Southerly gradients
increase over the eastern plains for breezy conditions there.

The upper trough ejects northeast from Utah into southern Wyoming
Sunday night. The best QG lift and moisture combination is staying
a bit farther north than advertised yesterday, so the chances of
showers on the adjacent plains has decreased in all but the
northern border area. Most of the mountains should still see a
round of snow starting Sunday evening, but the best backlash and
leftover moisture with stronger westerly orographics for Monday
morning appears to have shifted to near the Wyoming border area so
the higher storm totals (4 to locally 8+") will be confined to the
Park Range. Amounts of generally 2-5" expected for the northern
Front Range Mountains and RMNP, while Summit County and I-70
Mountain Corridor will be mostly shadowed during the best lift
Sunday evening - so look for 0.5-3" amounts there. Overall,
generally minor travel impacts expected Sunday night into early
Monday morning for the alpine areas above 9,000 feet, but enough
for slick and hazardous travel conditions due to temps falling
into the 20s Sunday night and allowing freeze-up.

Cooler air infiltrates the region Monday behind the upper level
trough/cold front, which will then stick around through Tuesday
despite dry conditions and upper ridging. It will also be windy
over the northern mountains and northeastern plains Monday in this
system`s wake. Potential gusts to 50-60 mph and some blowing snow
over the higher peaks Monday, while the northeast plains could
see gusts to 35-40 mph depending on how low level gradients
respond.

The main question that lies ahead is the track and intensity of
the next storm system that could impact the area anywhere from
late Wednesday into Friday. Operational models including the GFS
and ECMWF were trending more toward a solution of kicking the
next upper level low from southern California east/northeast
across the Southern/Central Rockies and into the adjacent High
Plains by Thursday or Thursday night, a rather favorable track for
significant precipitation. Ensembles were trending this way as
well, but at a much slower pace and a considerable amount of
those had differing tracks or much weaker solutions. Meanwhile, a
look at AI output over the last two runs showed much higher
probabilities (~80%) for measurable precipitation for the forecast
area including Denver and northeast plains Thursday to Friday,
with 35-50% having measurable snowfall for Denver. Operational
ensembles meanwhile, had about 10-20% lower odds but the trends
were higher over the last 12-24 hours. Considering the latest
trends, we have increased PoPs from previous forecasts.

This storm system bears watching given potential for a negatively
tilted system, which would spell incorporation of gulf moisture,
slower movement, deeper upslope, and significant precipitation. It
should also be noted that temperatures could end up on the
marginal side for snow. Finally, it needs to be stated that the
trough could get kicked out much faster and weaker than the latest
operational runs. There is a LOT of uncertainty at this point and
stay away from picking/choosing any one particular run. However,
given the potential noted above, this storm system and the latest
trends will be monitored closely over the next couple days.

&&

.AVIATION /18Z TAFS through 18Z Sunday/...
Issued at 1055 AM MST Sat Nov 15 2025

VFR through the TAF period. Winds are starting to become VRB at
this initial 18Z time, and trend should be for a more E or SE
component through 21Z-01Z with hints of a developing anticyclone.
Still some uncertainty of course, but that`s the most likely
outcome with lower probabilities of winds just staying VRB. After
01-02Z, it appears winds will start to trend more SE through 04Z,
and eventually S-SW 05Z-10Z. Most models are still in agreement
with more W/SW then occurring 10Z-18Z, before the gradual
transition back to a more easterly component by 21Z Sunday. Speeds
should stay mostly 10 kts or less, but a chance of 10-15 kt E/SE
winds 21Z-01Z this afternoon. It also appears KBJC winds have
finally decreased and they too should finally conform to lighter
diurnal wind patterns for this TAF period.

&&

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

&&

$$

DISCUSSION...20
AVIATION...20