837
FXUS65 KBOU 171152
AFDBOU

Area Forecast Discussion
National Weather Service Denver/Boulder CO
552 AM MDT Mon Aug 17 2026

.KEY MESSAGES...

- Warming trend for Monday and Tuesday, with isolated to scattered
  showers and thunderstorms.

- More active weather day shaping up for Wednesday with scattered
  severe thunderstorm threat.

- Warmer again through the coming weekend with above normal
  temperatures. Drier Thursday and Friday, but some monsoonal
  moisture likely returns by the weekend.

&&

.DISCUSSION /Through Sunday/...
Issued at 155 AM MDT Mon Aug 17 2026

Flow aloft has turned more zonal, bringing drier air into the area.
This, combined with lower dewpoints at the surface, will
decrease our precipitable water values to near normal for this
afternoon. High res models are showing a dryline forming this
afternoon somewhere near or to the east of the I-25 corridor.
Dewpoints will be in the 30s on the west side and 50s to low 60s
on the east side. Coverage of showers and storms looks much lower
for today, but if an isolated shower or storm can get going this
afternoon, the location of the dryline will play a role in the
potential hazards associated with that activity. To the west of
the dryline, we`ll be more worried about virga leading to gusty
winds. To the east of the dryline, better instability and shear
could allow for an isolated strong to severe storm to develop. The
main threats will be strong winds and hail, but we could also see
some heavy rainfall and localized flash flooding where the
dewpoints and moisture is the highest.

A weak cold front is forecast to move through the plains Tuesday
morning and afternoon. The cold front will help to limit warming
at the surface for a good portion of our area, even with the
expanding thermal ridge. The temperatures will warm the most in
our southern counties (especially southern Lincoln) due to the
delayed impact of the front. Moisture will be higher behind the
front and winds will be breezy from the east/northeast. This could
lead to some decent upslope in the mid to late afternoon. Shear
will be strong (~40kts at 0-6km) behind the front, but our potential
limiting factor when it comes to severe weather will be the lower
instability values. MLCAPEs are forecast to generally be below
500 J/kg, with the exception of our far eastern plains counties,
where there some potential for an isolated severe storm. A few
models are keeping isolated convective activity going into the
late evening and potentially even the overnight hours, as residual
boundaries lead to surface convergence. So, this is something
we`ll have to keep an eye on.

On Wednesday, temperatures will be slightly cooler and there`s
potential for scattered showers and thunderstorms. Low level
moisture will remain elevated behind the front and easterly surface
winds will provide another day of upslope flow. Aloft, an upper
level disturbance will move through providing additional lift.
Shear will remain high and instability looks to increase slightly,
so we could see a few strong to severe thunderstorms in the
plains.

Upper level ridging will build over the area Thursday into the
weekend. Temperatures will go back above normal, into the mid 80s to
mid 90s across the plains. Rain chances will decrease for Thursday
and Friday, with a low chance (

NWS BOU Office Area Forecast Discussion