951
FXUS65 KBOU 031139
AFDBOU

Area Forecast Discussion
National Weather Service Denver/Boulder CO
539 AM MDT Mon Aug 3 2026

.KEY MESSAGES...

- Hot again today, with temperatures reaching into the upper 90s
  and lower 100s before a cold front brings relief by this
  evening.

- Heat Advisory continues until 6PM tonight for the I-25 corridor
  and Weld County.

- Elevated fire weather conditions are expected across the eastern
  plains this afternoon.

- Cooler for Tuesday and Wednesday before temperatures gradually
  warm back to the triple digits by next weekend.

&&

.DISCUSSION /Through Sunday/...
Issued at 1243 AM MDT Mon Aug 3 2026

We will kick off the work week with one more day of hotter than
normal temperatures before a cold front brings some relief for
Tuesday and Wednesday. The Heat Advisory remains in place through
6 PM tonight along the I-25 corridor and Weld County. With poor
overnight recoveries (much of the lower elevations remain in the
70s and 80s as of 230 AM), it won`t take long for temperatures to
heat back up to uncomfortable values. Of course, there is the
possibility that the cold front picks up its pace and arrives
sooner than expected, which would prevent temperatures from
heating to the current forecast highs. Considering temperatures
are a few degrees warmer tonight compared to this time yesterday,
and most locations hit the mid 90s by early afternoon on Sunday,
confidence remains fairly high that most locations will reach the
triple digits before the front arrives, with highest confidence
for locations from Fort Collins and Greeley southward across
metro Denver. While most people will be happy to see a few days of
relief from the heat, we are expecting smoke concentrations to
increase with the approaching airmass from fires outside our
region.

Precipitation chances will remain fairly low today, with the
general expectation being that high-based showers will develop
early afternoon across the higher elevations and bring gusty
outflow winds and microburst potential as they pass by. DCAPE
values will range from 1500-2000 J/kg, which would make for
potential for an isolated severe gust, but expecting 35-45 mph
gusts with the majority of what develops. If any precipitation
does manage to make it to the ground, it is expected to remain
very light (a few hundredths). Winds are expected to become gusty
with the frontal passage that will likely see some localized
elevated to near-critical fire weather conditions until relative
humidity has time to improve behind the front. There is a slight
chance that a few thunderstorms develop along the front that could
lead to some dry lightning concerns as well since little
precipitation is expected. Overnight lows tonight are expected to
be about 10-15 degrees cooler than Sunday night across the lower
elevations.

On Tuesday, northern Colorado will sit on the southern edge of a
40 kt 500 mb jet that will increase winds across the higher
elevations. While the lower elevations will see much cooler
temperatures compared to the past few days, as 700 mb temperatures
cool by about 10C over the plains, there will be far less cooling
across the mountain valleys (700 mb temps only cool by a few
degrees C). Afternoon highs will struggle to get out of the 70s
across the lower elevations, where North and Middle park will warm
into the mid 80s. With the increasing winds expected across our
mountain valleys coinciding with relative humidities in the mid-
teens, we are expecting elevated to critical fire weather
conditions to develop in North and Middle Park in the afternoon.
The jet is expected to drop slightly southward on Wednesday that
will keep critical fire weather concerns in place for the higher
elevations once again, where relative humidities are expected to
drop into the single-digits.

Precipitation chances will remain limited through the week, with
the best chances for any accumulations expected over the Central
Mountains on Tuesday afternoon, and our northeastern corner on
Wednesday. By Thursday, the ridge is expected to rebuild over the
western CONUS and temperatures are expected to gradually increase
each day until they approach the triple-digits again by next
weekend.

&&

.AVIATION /12Z TAFS through 12Z Tuesday/...
Issued at 530 AM MDT Mon Aug 3 2026

There are three main topics to discuss for potential impacts
across the Denver TAF sites this TAF period. The first will be
with the potential for high-based virga showers developing over
the higher elevations by early afternoon and moving eastward over
the TAF sites by the 19/20Z time frame. The latest trend in
guidance has moved closer to the 20Z start time. DCAPE values are
expected to be fairly impressive (1500-2000 J/kg), and with
little moisture expected, the main concern will be with strong
gusty outflows/microbursts producing gusts between 35-45 kts as
they pass by. Timing for greatest potential will be between 20Z
to 0Z. The next concern is with the arrival of a cold front. There
is still some uncertainty with its exact arrival time, but gusty
northerly winds are expected beginning around 22-24Z for KDEN/KBJC
followed by KAPA about an hour after. The initial northerly push
is expected to bring 20-25 kt northerly winds, with winds expected
to increase by another 10-15 kts by 3/4Z. While there isn`t a lot
of moisture expected behind the front, there will be low
potential for an isolated thunderstorm to develop with the frontal
passage. Probabilities aren`t high enough to add in the TAF at
this point, but there is a nonzero chance that we see something
develop outside of the current PROB30. With north/northeasterly
flow expected behind the front, we could see a few hours of
ceilings drop to around BKN040-050 late tonight (around 6/7Z),
before gradually lifting early Tuesday morning.

Finally, smoke concentrations are expected to intensify
significantly behind the front that will likely bring visibility
concerns through the rest of the TAF period. Depending on the
exact timing of the front, there could be slant-range visibility
concerns as early as sunset tonight, but the greater
concentrations aren`t expected until 3/4Z tonight.

&&

.BOU WATCHES/WARNINGS/ADVISORIES...
Heat Advisory until 6 PM MDT this evening for COZ038>043.

&&

$$

DISCUSSION...9
AVIATION...9

NWS BOU Office Area Forecast Discussion