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 (<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 /12Z TAFS through 12Z Tuesday/...
Issued at 545 AM MDT Mon Aug 17 2026

Winds this morning will be light generally from the
south/southwest. Winds will become more variable around 17Z, with
the winds turning clockwise before eventually becoming easterly
around 20Z to 21Z. Chances for showers or thunderstorms today is
low (<20%). Winds could become breezier at KDEN and KAPA for a 
few hours late this evening from the southeast around 10 to 15kts.
Winds at KBJC will become light and variable during this time.
Overnight, winds should turn more towards drainage, before turning
more northerly by the late morning. 

&&

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

&&

$$

DISCUSSION...AP
AVIATION...AP