Copper Mountain

000
FXUS65 KBOU 221753
AFDBOU

Area Forecast Discussion
National Weather Service Denver/Boulder CO
1153 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 /18Z TAFS through 18Z Sunday/...
Issued at 1131 AM MDT Sat Aug 22 2026

A boundary currently to the east of DEN and APA will continue to
move westward towards each of those terminals. It now appears
likely the boundary will get close enough to both of those
terminals to bring stronger easterly winds than previously
forecast. East winds could gust to around 20 knots. There is a
slight chance (20%), however, that a DCVZ develops just to the 
east of DEN and APA that keeps winds more out of the northeast 
with lighter speeds. 

Storms are expected to develop this afternoon with the earliest
possible storms at 19Z at BJC and 20Z at DEN and APA. The most
likely time for storms to impact all terminals is between 22-02Z.
Strong outflow winds are likely with gusts 40-45 knots. It is even
possible (20%) that severe gusts above 50 knots occur at DEN or 
APA. Besides winds, there is a chance (40%) that visibility will 
be reduced to 2-4 miles and ceilings drop to 4,000-6,000 feet if a
storm were to move directly overhead. 

In the evening, southerly winds are likely to develop at DEN and
APA with a small chance rain showers move overhead with little
impact. Drainage winds are expected for much of the night at all
terminals. 

Normal wind patterns are expected throughout the day on Sunday.
There will be less low level moisture in place and coverage of
showers and storms will be lower as a result. However, an outflow
boundary or two is still expected to impact the terminals late 
tomorrow afternoon and early evening. 

&&

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

&&

$$

DISCUSSION...9
AVIATION...Danielson