074
FXUS65 KBOU 261130
AFDBOU

Area Forecast Discussion
National Weather Service Denver/Boulder CO
530 AM MDT Wed Aug 26 2026

.KEY MESSAGES...

- Scattered afternoon and evening thunderstorms expected for the
  I-25 Corridor and plains. A few storms could become severe, with
  large hail and strong outflow winds possible.

- Another round of showers and thunderstorms expected on Thursday,
  however coverage will be more limited.

- Gradual drying and hotter temperatures by Friday and the
  weekend, but a few storms still possible especially on Sunday.

&&

.DISCUSSION /Through Tuesday/...
Issued at 226 AM MDT Wed Aug 26 2026

Current surface observations across the plains show low dewpoint
depressions due to outflow boundaries advecting low-level moisture
into the area. This could create areas of patchy fog as the sun
rises this morning, but expect it to quickly burn off with daytime
heating. Most model guidance has now backed off on a low stratus
deck this morning. However, with a cluster of storms moving through
the eastern plains early currently, will be keeping an eye on the
formation of that stratus deck for the next few hours. If these low
clouds do form, it will limit the severe weather threat later this
afternoon.

As of now, we are still on track for a round of thunderstorms this
afternoon across the forecast area, with the potential for some to
become severe across the I-25 Corridor and adjacent plains. A weak
shortwave will track across eastern Colorado this afternoon, which
should provide enough forcing to support scattered to numerous
storms. However, CAMs show a variety of solutions of storm
development over the I-25 Corridor, ranging from isolated-to-
scattered convection to numerous thunderstorms. This is likely
attributed to models backing off on instability immediately off the
foothills, with MLCAPE generally below 1000 J/kg (aside from the
NAM, which still shows MLCAPE up to 1200-1400 J/kg for the Denver
metro). Will need to keep an eye on how the environment evolves this
morning. Regardless, won`t be surprised if we see a few severe
thunderstorms over the I-25 Corridor given decent shear profiles.
These storms will be capable of producing hail and strong winds.

Models are in decent agreement of storms clustering further
east/southeast in the late afternoon/early evening as they tap into
better instability and shear profiles. As of right now, have better
confidence in the severe weather threat for areas south of
Interstate 76, where hail up to 1.5 inches and strong winds of 60-65
mph possible. There is also a flooding threat given PWAT values of
125-150% of normal. However, given the expected fast storm motion of
these storms, thinking it will be more of an isolated threat
associated with the strongest convection. Expect thunderstorms
activity to be completely out of the forecast area by 10/11 PM
tonight.

We will begin to warm up again on Thursday as the axis of the mid-
level thermal ridge shifts slightly towards the forecast area. It
looks like most of the plains will get up to the high 80s, but some
areas will likely reach the low 90s by the afternoon. Another
round of scattered showers and thunderstorms is possible. However,
expect coverage to be more limited compared to Wednesday, given
less moisture availability. A few storms could become severe
across the eastern plains with favorable instability and shear
profiles. However, warming aloft will likely suppress most
convection.

Ensemble guidance continues to favor heat rebuilding over the
area, with temperatures reaching back up to the mid-90s by Friday
and Saturday. With the upper level ridge shifting east over
Colorado, moisture will be cut of. However, there should still be
enough lingering low-level moisture to support a isolated
afternoon storms. Then, by the end of the weekend/beginning of
next week, a strong upper level shortwave will track from the
Pacific northwest across the northern United States. This will
likely bring cooler temperatures once again, and another round of
showers and thunderstorms.

&&

.AVIATION /12Z TAFS through 12Z Thursday/...
Issued at 523 AM MDT Wed Aug 26 2026

VFR conditions expected through the TAF period. Winds are
currently from the east/southeast due to an outflow boundary from
thunderstorms over the eastern plains. There is some uncertainty
with how these winds will evolve in the near future, but most
guidance has light drainage flow returning. For now, have opted in
to follow guidance, but winds could remain from the east through
the early morning hours. Patchy areas of fog and the low stratus
deck have not materialized over the plains yet, so have taken the
lower clouds out of the TAF. However, if easterly winds remain at
the airport, there is a chance (<30% at this time) that low
stratus deck could form. Will continue to monitor.

Scattered afternoon showers and thunderstorms are still expected
at all TAF sites this afternoon, with gusty outflow winds of 30-40
kts possible. Convection still looks on track to leave the
terminals by 01Z, however there could be nearby storms lingering
through 03Z. Behind convection, winds will likely be from the
southeast due to outflow boundaries, before drainage flow returns
to the terminals.

&&

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

&&

$$

DISCUSSION...MAI
AVIATION...MAI