133
FXUS65 KBOU 291742
AFDBOU

Area Forecast Discussion
National Weather Service Denver/Boulder CO
1142 AM MDT Sun Mar 29 2026

.KEY MESSAGES...

- Well above normal temperatures continue today and Monday.

- Critical fire weather conditions becoming widespread Monday.

- Cooler by Tuesday with snow in the mountains and a chance of
  precipitation over the plains.

- Potential for a stronger system to impact the region by the end
  of the week.

&&

.UPDATE...
Issued at 300 AM MDT Sun Mar 29 2026

On Monday, we see the strongest winds generally along and west of
I- 25 with low (less than 15%) relative humidities in the
foothills and plains. Where the stronger winds and lower relative
humidities overlap, decided to issue a Fire Weather Watch for the
foothills and nearby plains. The approaching shortwave trough
increases mid level moisture with scattered high-based showers
during the afternoon and early evening. No rain is expected to
reach the ground under the showers, but wind gusts to 40 mph will
be possible under the microbursts. Relative humidities begin to
increase over the mountains and mountain valleys by mid afternoon,
so opted to leave them out of the Fire Weather Watch at this time
though wind gusts to 35 mph will be possible.

&&

.DISCUSSION /Through Saturday/...
Issued at 1135 PM MDT Sat Mar 28 2026

Significant changes are expected as we approach the end of the
month. This weekend`s anomalously high/record-breaking
temperatures will continue into Monday afternoon before the next
shortwave traverses the northern Rockies, and an associated cold
front slides south across Colorado Monday night into Tuesday
morning. This looks to be the initiation of a more active pattern
through the long term forecast period.

Starting Sunday, a persistent, flattened ridge pattern will remain
in place across the region. Lee troughing will continue to support
downsloping winds, bringing another day of record-breaking
temperatures, dry conditions, and elevated fire weather conditions
to the forecast area. RH is expected to drop below critical
thresholds across the plains and southern mountain valleys by the
early afternoon, however, our strongest winds are forecast for North
Park where RH is expected to remain in the upper teens. Should see
some patchy elevated to near critical fire weather conditions for a
few hours in the afternoon, but coverage and duration are not
sufficient to warrant any highlights. High-based virga showers may
develop once again, although slightly less moisture and instability
are expected compared to Saturday. Nonetheless, gusty outflows with
speeds up to 25-30 mph are possible as virga passes by.

Winds are expected to increase on Monday as our next shortwave moves
east out of the Pacific Northwest. This will track along the
northern tier and cross the northern Rockies in the afternoon and
evening. The aforementioned lee trough will continue to deepen as
the shortwave approaches, and an associated cold front is expected
to drop south across Colorado late Monday night into early Tuesday
morning. Ahead of the cold front, one last day of well-above-normal
temperatures is expected. With the strengthening winds, critical
fire weather conditions will likely become more widespread across
the plains, as RH values drop to around 10% for the afternoon. The
current forecast has Middle Park reaching critical thresholds, while
RH looks to be in the upper teens for North and South Park, so
things are more marginal in these areas. Given the warm and dry
conditions in the days leading up to this, fuels will be dry and
receptive. As a result, might need highlights in these areas despite
RHs being marginal.

Tuesday will be much cooler with ample moisture to support
widespread precipitation across the forecast area. Cross sections
show a deep moisture profile by Tuesday morning, with upslope
flow up to about 700 mb in place across the plains. Both the GEFS
and EPS ensembles show between .15" to .2" of QPF for the plains
and up to .5 to .6" for the mountains through Wednesday morning,
with southwesterly flow aloft expected to continue bringing
moisture into Colorado through Wednesday (PWAT anomalies show
values reaching up to 250% of normal on Wednesday). Cold air
behind the front will drop snow levels down to which would support
mixed precipitation for the plains, but snow is only expected to
accumulate in the mountains above roughly 10,000 feet, and as low
as 8,500 feet just in Larimer County, but we may see a dusting to
a few tenths for some of the lower elevations (NBM probabilities
has a 50% chance of .2" or greater for areas along the Wyoming
border). Another shortwave is expected to keep precipitation
chances through Wednesday, before a stronger upper-level trough
drops out of the Pacific Northwest on Friday that will impact the
region for the weekend. While there is still time for things to
change, current trends indicate that the northern mountains could
see up to a foot of new snow between Tuesday and Wednesday, with
more possible later in the week depending on the track of the next
system. This certainly won`t make up for the large snowpack
deficit, but it would allow for at least one more decent ski day
before the end of the season!

&&

.AVIATION /18Z TAFS through 18Z Monday/...
Issued at 1139 AM MDT Sun Mar 29 2026

Winds should stay west-northwesterly early this afternoon at DIA,
then become more northwesterly by late afternoon.  Models have
southeasterlies in by around 00Z-01Z for a few hours this evening
before light drainage winds kick in by 06Z-07Z. I left the VCSH in
with some of the models continuing to show weak convection later
this afternoon.  Precipitation is not expected.  There will be no
ceiling issues.

&&

.BOU WATCHES/WARNINGS/ADVISORIES...
Fire Weather Watch from Monday morning through Monday evening
for COZ215-216-238>240-242-243.

&&

$$

UPDATE...12
DISCUSSION...9
AVIATION...66

NWS BOU Office Area Forecast Discussion