233
FXUS65 KBOU 221155
AFDBOU

Area Forecast Discussion
National Weather Service Denver/Boulder CO
555 AM MDT Sat Aug 22 2026

.KEY MESSAGES...

- Heat eases, along with an increase in shower and storm coverage
  this weekend.

- Highest coverage of showers and storms expected today, along
  with a few severe storms on the plains this afternoon and
  evening and then again Sunday.

- Gradual drying next week, but continued storm chances through
  at least Wednesday or Thursday. Slight cooling but temperatures
  still above normal.

&&

.DISCUSSION /Through Friday/...
Issued at 249 AM MDT Sat Aug 22 2026

A slight cooldown is expected today after Friday`s record breaking
heat. While temperatures are still expected to remain above
normal, we should only see highs range from the mid 80s to the low
90s across the lower elevations before afternoon showers and
storms bring some heat relief. Not much has changed in today`s
forecast, as we still expect today to bring this week`s best
chance for wetting rains as PWATs are expected to be around 150%
of normal. Instability will increase today, with high-res models
showing a wide range of values (600-3500 J/kg of MLCAPE). Despite
these models having inconsistent MLCAPE values, they are in
fairly good agreement that the best environment for severe storms
will be along a line from the Cheyenne Ridge southeastward across
the plains, just east of DIA. As storms are expected to remain
high-based as they move off the higher terrain, they will be
capable of producing gusty outflows, with a few strong to severe
gusts expected throughout the afternoon and evening as storms move
across the plains. With the above normal PWATs in place, we could
have a few localized heavier rains too. Additionally, mid-level
lapse rates will be sufficiently steep (8-9 C/km) to support an
isolated hail threat. 0-6 km shear will be marginal (~30 kts), but
enough to support potential for storm organization.

The upper-level ridge is still expected to flatten out on Sunday
and Monday as a shortwave tracks east out of the Pacific
Northwest. While moisture isn`t expected to be as robust as today,
PWATs are still expected to be around 120% to 130% of normal each
afternoon that will support afternoon showers and storms, with a
few strong to severe storms possible each afternoon, and above
normal temperatures persisting before a chance at sub 90 degree
highs returns Tuesday and Wednesday.

The latest ensembles keep above normal PWATs in place through the
week though a gradual drying is still expected. This will keep
at least isolated to scattered afternoon showers and storms
possible through the week. The upper-level ridge is then expected
to rebuild, bringing temperatures right back into the 90s across
the plains to end the work week.

&&

.AVIATION /12Z TAFS through 12Z Sunday/...
Issued at 531 AM MDT Sat Aug 22 2026

Drainage winds are still expected to turn clockwise and land in
a northeast flow across all TAF sites by early this afternoon
(16-18Z). Greater storm coverage is expected this afternoon
compared to yesterday, with storms expected to move off the higher
elevations between 20-22Z and continue through late tonight
(5-6Z), though coverage and intensity will decrease significantly
between 2-3Z as the brunt of showers/storms move to the eastern
plains. Gusty winds are expected with passing storms, with gusts
between 35-45 kts possible, but can`t rule out a severe storm
passing over or near the TAF sites (most likely just east of KDEN).
Storms are expected to be high-based, with guidance showing CIG
staying above 8,000-9,000 feet AGL at their lowest. Like Friday
night, can`t rule out an outflow or two making their way across
the TAF sites after storms have diminished/pushed east that could
disrupt or delay drainage winds from taking hold, but south to
southwesterly winds are expected to settle in for the overnight
hours.


&&

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

&&

$$

DISCUSSION...9
AVIATION...9

NWS BOU Office Area Forecast Discussion