130
FXUS65 KBOU 042127
AFDBOU

Area Forecast Discussion
National Weather Service Denver/Boulder CO
227 PM MST Wed Mar 4 2026

.KEY MESSAGES...

- Warm Thursday, with critical fire weather conditions across the
  Palmer Divide and Lincoln County in the afternoon.

- Moderate to locally heavy snow is expected to impact the
  mountains and foothills Thursday night through Friday.

- A few inches of snow increasingly likely for most of the lower
  elevations, favoring minor impacts. Continued uncertainty makes
  the forecast especially dynamic, and potential for locally
  moderate travel impacts does exist for portions of the I-25
  corridor and plains.

- Warmer and drier Saturday through Monday. Cooler and windier
  conditions favored as early as Tuesday, with some potential for
  the return of snow to the region.

&&

.DISCUSSION /Through Wednesday/...
Issued at 1246 PM MST Wed Mar 4 2026

Warm advection ahead of an approaching and shearing trough will
lead to a warm and dry day across the region Thursday as
temperatures rebound into the upper 60`s in the plains. Efficient
mixing will allow for development of breezy winds roughly along
and south of I-70 in the afternoon, producing critical fire
weather conditions around the Palmer Divide. More information in
the Fire Weather discussion below.

Eyes then turn to our incoming winter storm Thursday night into
Friday, which is poised to bring our first widespread snow in
quite some time (Denver`s most recent measurable snow occurred
January 25th). Unfortunately, the onslaught of guidance over the
past 24 hours has shed limited additional light on the finer
details of the forecast.

Snowfall is set to develop in the high country late Thursday
evening and increase overnight, although the heaviest snow will
hold off until after daybreak. Meanwhile, a well-defined cold
front will descend into the plains late Thursday evening, kicking
off our I-25 corridor shower potential shortly after midnight.
Although a brief rain or rain/snow mix is conceivable on the front
end, the changeover to snow should occur quickly if that`s the
case, with increasing confidence in precipitation remaining as
snow throughout the day for the urban corridor and most of the
plains. Abundant QG lift will be in place through Friday
afternoon, and will be accompanied by strong low and mid-level
frontogenesis, which would support potential for some banded snow
as well as snow squalls (for both the mountains and plains) under
moderately steep lapse rates and given healthy low-level winds.
Surface flow will be largely northerly however, substantially
limiting the upslope component along the base of the
foothills/urban corridor in particular, with exception of the
Palmer Divide. The foothills themselves may fair slightly better,
with some cross-sections favoring a shallow corridor of more
easterly flow aloft. Road temperatures further compound the
accumulation uncertainty for the lower elevations, as it may be
difficult to keep them near freezing outside of any heavier bands
with enhanced snowfall rates, particularly in the morning.

Synthesizing the above in terms of potential impacts, there`s
enough information to indicate we`ll see quite difficult travel
across the mountains and foothills in particular throughout the
day on Friday, where a broad axis of 4-12" accumulations is
expected and winter weather highlights have been issued. Such
impacts are likely to be present for parts of the plains/urban
corridor as well, but should be more localized and transient. The
Palmer Divide looks slightly better positioned for more impactful
accumulations exceeding 3-5", but model consistency and thus
confidence is just not there yet to move forward with any
headlines. Nonetheless, at least 1-2" of snow accumulation looks
quite reasonable (~70% chance) for a majority of the urban
corridor through Friday evening. Drier subsident flow will fill in
relatively quickly overnight, tapering off all snow by daybreak
Saturday.

Quieter weather is in store for the weekend and into Monday, with
a gradual transition to more zonal flow and a steady warming
trend, culminating in a potential return to highs in the 70`s come
Monday. Some change is then expected as early as Tuesday or
Wednesday with ensembles favoring an amplyfying trough to our
north. How far south it`s able to dig will determine the type and
extent of impacts. At the very least, some cooler and windier
weather appears to be on the horizon for the middle of next week.
Precipitation potential is more questionable.

&&

.AVIATION /18Z TAFS through 18Z Thursday/...
Issued at 1044 AM MST Wed Mar 4 2026

Normal diurnal wind patterns are expected today at DIA; with weak
east/southeasterlies this afternoon, then weak drainage winds from
late evening on into Thursday morning. There will be no ceiling
issues.

&&

.FIRE WEATHER...
Issued at 1246 PM MST Wed Mar 4 2026

South to southwest winds will increase on Thursday in advance of
the incoming storm system. Downslope flow off the Palmer Divide
will result in warm and dry conditions, with humidity falling into
the 10-15% range. Mixing heights should be quite elevated, and
help promote efficient mixing of winds aloft down to the surface.
The stronger flow aloft, however, likely won`t arrive until later
in the afternoon, thereby shortening the window of critical
conditions slightly (mainly mid and late afternoon), when gusts
25-30 mph will be most likely. Tuesday`s wetting rains were rather
localized and not widespread across the warned zones, so fuels
were deemed susceptible and the Fire Weather Watch was
consequently upgraded to a Red Flag Warning for the areas of
strongest winds (Palmer Divide into Lincoln County).

&&

.BOU WATCHES/WARNINGS/ADVISORIES...
Winter Weather Advisory from midnight Thursday night to 8 PM MST
Friday for COZ031.

Winter Storm Watch from late Thursday night through Friday
evening for COZ033-034.

Winter Weather Advisory from midnight Thursday night to midnight
MST Friday night for COZ035-036.

Red Flag Warning from noon to 6 PM MST Thursday for COZ241-246-
247.

&&

$$

DISCUSSION...BRQ
AVIATION...66
FIRE WEATHER...BRQ

NWS BOU Office Area Forecast Discussion