026
FXUS65 KBOU 070543
AFDBOU

Area Forecast Discussion
National Weather Service Denver/Boulder CO
1143 PM MDT Sat Jun 6 2026

.KEY MESSAGES...

- Widespread critical fire weather conditions expected in fuel-
  prone areas by Tuesday and Wednesday.

- Hottest temperatures Sunday, and then again Tuesday and
  potentially Wednesday. Highs generally in the mid 90s across the
  I-25 Corridor and plains, but near 100 possible over the
  northeast plains Tuesday.

- Brief respite in the heat Monday, and then increasing heat
  relief late next week.

&&

.DISCUSSION /Through Saturday/...
Issued at 251 PM MDT Sat Jun 6 2026

Current water vapor imagery shows Colorado is currently sitting
between an upper-level low over TX/OK and an upper-level low
entering the Pacific Northwest this morning, placing Colorado on the
western side of an upper-level ridge. The main weather concerns for
today will be with developing critical fire weather conditions
across portions of the plains, and with gusty outflows from high-
based showers/storms. Things have taken a little longer to dry out
over the northeast plains after early morning fog, but relative
humidities are already moving towards the teens and winds are
simultaneously increasing. Today`s Red Flag Warning will continue
until 7 PM this evening when RH values are expected to increase to
above critical thresholds (More on fire weather in discussion
below). High temperatures are expected to be in the 90s across the
plains, and 70s to 80s in the mountain valleys.

We are already seeing convection form along the higher elevations
early this afternoon, with a boundary stretching from the Palmer
Divide northward across Douglas County and towards DIA that has
kicked up a few showers that are producing some gusty microbursts
but little precip. This is expected to be the outcome from most
showers that develop this afternoon as ACARS soundings show large
dewpoint depressions already in place, and forecast soundings show
inverted-v profiles (DALR up to 500mb), that would limit chances for
most precip to reach the surface. Hi-res guidance has persisted in
showing shower coverage expand this evening generally south and east
of the Denver area, so have increased PoPs to account for this
potential, with the greatest precip chances expected along and just
north of the Palmer Divide. We are expecting gusty outflows from
these with potential for some gusts to 50 mph.

For Sunday, hot temperatures are expected once again, but winds are
expected to slacken a bit across the lower elevations that would
limit any critical fire weather conditions from developing. The
approaching upper-level low over the Pacific Northwest is expected
to move eastward and into the Northern Rockies through the day and
lee troughing is expected to deepen as a response. This will enhance
compressional warming and we should see temps a few degrees warmer
than today`s. There should be enough mid-level moisture present to
see some afternoon showers, with the best chances for the
northeastern plains.

Monday will bring a slight cooldown, with afternoon highs expected
to drop back into the 80s for the urban corridor. A surface trough
is expected to increase low-level moisture and there will be enough
instability in place to allow for some afternoon convection.
Forecast soundings indicate enough MUCAPE (1200-1600 J/kg) and shear
(EBWD >30 kts) from increasing southwesterly flow aloft in place
for isolated strong to severe storms to develop, mainly for areas
east of I-25.

Tuesday and Wednesday are still on track to be hot, dry, and windy,
with critical fire weather conditions expected under well-above
normal temps. See Fire Discussion below for more details. Winds are
expected to increase with a strengthening pressure gradient both
aloft and at the surface. There are still some uncertainties with
the timing of an upper-level trough over the Northern Rockies, but
this will be the deciding factor on just how hot temperatures get on
both Wednesday and Thursday, as an associated cold front is
expected to drop south into Colorado. Latest guidance is trending
towards the faster trough ejection, which would move the hotter
temps to the east a little sooner, with near-normal temps
expected to end the week.

&&

.AVIATION /06Z TAFS through 06Z Monday/...
Issued at 1142 PM MDT Sat Jun 6 2026

Strong and gusty southerly winds were finally relaxing as of
0530Z, and will continue to diminish through 08Z with normal S-SW
winds then expected through 15Z. Winds may become VRB for a few
hours 15Z-21Z, although a trend to W-NW still expected with peak
heating and some mixing. However, that`s only about a 50-60%
chance since strong diurnal heating and resultant upslope will
offset the mixing component. What is more concerning is potential
for virga and thus VRB G35+ kt microburst winds. DCAPE is
advertised to be at least 1400 J/kg and still just enough
moisture to produce virga from about 17-18K ft MSL. Thus, we opted
for Prob30 to message that gust potential, most likely 20Z-24Z.

&&

.FIRE WEATHER...
Issued at 251 PM MDT Sat Jun 6 2026

A Red Flag Warning will remain in place until 7 PM this evening
across portions of the plains for low RH, gusty winds, and dry
lightning potential. Winds are expected to gradually increase
through the afternoon from east to west across the plains, with
gusts between 25-35 mph. Additional gusty winds will be possible
through the evening from outflows associated with showers/storms
(up to 50 mph possible).

For Sunday, we are expecting elevated fire weather conditions to
develop across the plains as RH values are forecast to drop into
the single digits to low teens in the afternoon. Winds are
expected to remain below critical thresholds for the majority of
the plains, but we are expecting winds to increase for our higher
mountains and valleys where fuels have yet to reach critical
dryness. No fire highlights are anticipated for Sunday.

We are still anticipating minimal fire weather concerns on Monday
as we see increased moisture and cooler temperatures, but things
will ramp up for the rest of the forecast period as winds are
expected to increase ahead of an approaching upper-level trough
amidst near record-high temperatures. HDWI still continues to show
Tuesday likely reaching above the 95th percentile and above the
90th for Wednesday. These are expected to be the two most critical
days for the majority of the forecast area as the forecast has RH
ranging from 8% to 12% (Tues) across all of the plains with
widespread 30-40 mph gusts, and 10-15% RH (Wed) with another day
of 30-40 mph gusts expected. There are still some uncertainties on
Thursday`s outcome with the timing of the approaching trough, but
critical fire weather conditions may persist, though there should
be some improvements to both RH and winds for Thursday, and the
HDWI does have the majority of its members dropping us down to the
below the 75th percentile.

&&

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

&&

$$

DISCUSSION...9
AVIATION...20
FIRE WEATHER...9

NWS BOU Office Area Forecast Discussion