737
FXUS65 KBOU 170805
AFDBOU

Area Forecast Discussion
National Weather Service Denver/Boulder CO
205 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 (<30%) for some isolated activity
in the afternoons. PWs do start to increase for the weekend, with
a little disturbance or two aloft, increasing our rain chances.

&&

.AVIATION /06Z TAFS through 06Z Tuesday/...
Issued at 1120 PM MDT Sun Aug 16 2026

Breezier southeast winds around 10 to 15kts at KAPA and KDEN will
gradually weaken and turn more to the southwest by 09Z. Drainage
winds should prevail for the rest of the overnight period at KDEN
and KAPA, before winds become light and variable in the late
morning. Southwest winds will turn more northerly and eventually
easterly by the early afternoon. Winds at KBJC will be more
northwesterly tonight, turning southwesterly by the early
morning, before becoming variable around 14Z. There is potential
for some patchy fog tonight, but it should be much more isolated
and less dense then this morning. Impacts from fog are not
expected at the TAF sites. Tomorrow there is a low chance for some
showers and thunderstorms (<20%) near the TAF sites, but coverage
is forecast to be too low to include in the TAF at this time. A
few models are hinting at stronger southeast winds impacting KDEN
and KAPA around 02Z to 05Z tomorrow. We`ll have to keep a close
eye on the gusty wind potential during that time to see if it
needs to be added to the TAF if confidence increases.

&&

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

&&

$$

DISCUSSION...AP
AVIATION...AP