350
FXUS65 KBOU 271117
AFDBOU

Area Forecast Discussion
National Weather Service Denver/Boulder CO
517 AM MDT Thu Aug 27 2026

.KEY MESSAGES...

- Thunderstorm coverage decreases Thursday and Friday with mainly
  isolated high-based showers/storms with gusty winds.

- Temperatures return to the 90s Friday andSaturday across the
  plains.

- Thunderstorm coverage increases for late Saturday and Sunday.

&&

.DISCUSSION /Through Wednesday/...
Issued at 228 AM MDT Thu Aug 27 2026

Throughout the day today, the axis of the upper level ridge will
shift east over Colorado, allowing warmer air to advect into the
region. 700-mb temperatures should reach up to 15-17 dg C which
roughly translates to temperatures in the high 80s to low 90s
across the plains. With the upper level ridge shifting eastward,
we will also start drying out over most the forecast area. This,
combined with warming aloft, will result in less thunderstorm
activity this afternoon, although CAMs still favor a few storms
developing over the Front Range and spilling onto the adjacent
plains. Given less moisture availability, main concerns for any
storm over the mountains and I-25 Corridor will be strong outflow
winds.

There is also a conditional threat for severe thunderstorms over the
far northeastern plains later in the afternoon/evening hours. Models
hint at a weak 700-mb shortwave north/northeast of Colorado,
which should provide forcing for thunderstorm activity over
Nebraska. While CAMs keep most of the storms out of Colorado
(with the 06Z runs less aggressive with thunderstorm activity
compared to the 00Z runs), can`t rule out an isolated storm
developing over the far northeastern plains (10-20% chance),
especially since that area will be able to hang onto the low-level
moisture and thus have better instability throughout the day.
Given MLCAPE values up to 1000-1500 J/kg and 0-6 Km bulk shear of
40 kts, storms would be capable of producing hail and strong
winds.

Warmer temperatures arrive by Friday and Saturday as the upper
level ridge continues shifting eastward, with highs reaching the
low-to- mid 90s both days. A strong upper level low over the
Pacific Northwest will cause flow aloft to increase and turn
west/southwest over Colorado. This will create breezy conditions
over the high terrain, but also re-introduce mid-level moisture
into the region. On Friday, we could see isolated high-based
showers and thunderstorms. But, Saturday afternoon looks better
for thunderstorm activity. Convection should be high-based, with
only a few storms producing beneficial rainfall.

Towards the end of the weekend/beginning of next week, the upper
level low will trek across the U.S./Canada border, with embedded
shortwaves moving over Colorado. "Cooler" temperatures (if you
consider 80s to be cooler) will arrive, along with better low-
level moisture. Ensemble guidance continues to favor storms
Sunday and Monday, but looks to have backed off for Tuesday due to
an exiting shortwave. This could still change depending on the
evolution of the multiple disturbances, so will keep an eye on it.

&&

.AVIATION /12Z TAFS through 12Z Friday/...
Issued at 507 AM MDT Thu Aug 27 2026

VFR conditions expected through the TAF period. Lighter winds have
begun filtering into the TAF sites a bit earlier than expected,
but expect generally a light southwest/westerly component
throughout the morning (more northwest for BJC). Surface
observations across the eastern plains have shown fog forming due
to low dewpoint depressions. There is a low chance (

NWS BOU Office Area Forecast Discussion