646
FXUS65 KBOU 120026
AFDBOU

Area Forecast Discussion
National Weather Service Denver/Boulder CO
626 PM MDT Sat Jul 11 2026

.KEY MESSAGES...

- Prolonged period of hot weather through the week ahead.

- Only hints of monsoon moisture reaching the high country by late
  next week.

- Prolonged hot and dry conditions will bring fire weather
  concerns although we`ll likely stay just shy of Red Flag
  criteria most days.

&&

.DISCUSSION /Through Saturday/...
Issued at 108 PM MDT Sat Jul 11 2026

Main concern for this entire forecast cycle will be the hot
weather. We will also have some fire weather concerns due to the
lengthy hot, dry spell.

In the short term, we are seeing some cumulus over the Front
Range but so far these have been pretty shallow thanks to a weak
stable layer near 500 mb. With further heating, it`s not
impossible we break the cap, with the elevated terrain of the
mountains south of I-70 and the Palmer Divide being the most
likely spots for isolated storms. They will produce gusty outflow
winds given high DCAPE and dry adiabatic lapse rates through 500
mb.

On Sunday, the heart of the upper level ridge will build northeast
across Wyoming and South Dakota. This means a deeper easterly flow
developing across the forecast area, but limited moisture and
instability. There could still be strong enough heating to break
the cap and allow for an isolated storm or two from the Palmer
Divide area into Park County. High temperatures will be nearly as
hot as today, although some models show a degree or two of
"cooling" on the east side of the Front Range with deeper
easterly flow.

There`s not a lot of change for Monday, but it appears this could
be one of the hottest days of the week ahead with high
temperatures tacking on a degree or two from Sunday. We`ll also be
starting off a few degrees warmer so there is still potential for
a Heat Advisory along the I-25 Urban Corridor as temperatures are
forecast to climb into the upper 90s. It should be a few degrees
cooler than that over the eastern plains, being farther away from
the mid level thermal ridge. Meanwhile, the mountains and points
west into northwest Colorado will be centered under the thermal
ridge, which given the amplitude of this heat dome we`ll be seeing
forecast maximums approaching all time records. A few examples
would be; in North Park (Walden - 94F), in Middle Park
(Kremmling - 94F and Grand Lake - 88F, in Summit County (Dillon -
89F), and in South Park (Fairplay - 84F). These will be
approached most afternoons for the entire week ahead as 700 mb
temperatures are forecast to reach an astonishing +23-24C.

As the heat and stress on vegetation builds, we`ll see increasing
risk of fire growth and potentially long burn periods well into
the evening hours each day. That`s despite staying just below Red
Flag conditions each day as the wind component will be lacking
slightly in the mountains, while the humidity component will be
slightly above thresholds over the breezier plains east of I-25.

For those looking for a change, unfortunately the main
change/trend over the last 24 hours was for a slower arrival of
monsoonal moisture. That is mainly the result of what is now
forecast to be a more elongated upper level ridge building back
into the Central Rockies and Great Basin. That would mean the
monsoonal moisture plume gets shunted farther west and we stay
under the influence of large scale subsidence and drying. As a
result, we may not see much uptick in shower or storm coverage
until next weekend or even sometime the following week.

&&

.AVIATION /00Z TAFS through 00Z Monday/...
Issued at 621 PM MDT Sat Jul 11 2026

VFR conditions expected through the TAF period. There is still a
concern (20% chance) of showers and thunderstorms for the next few
hours, mainly at DEN, if colliding wind boundaries occur over the
airport. However, due to continued low confidence of this
happening, have kept it out of the TAF. Winds will likely be from
the southeast this evening, with the exception of outflow
boundaries from surrounding convection. Overnight, winds should
transition to drainage.

Tomorrow, a weak cyclone may form, which would bring light (

NWS BOU Office Area Forecast Discussion